Fixing device and image forming apparatus

Abstract

A fuser and an image forming apparatus are provided. The fuser includes: a pair of pressing members that sandwich a recording material holding an unfixed image therebetween and apply pressure; a plurality of pressing mechanisms that transmit a force to at least one of the pair of pressing members to generate the pressure; and a plurality of elastic members that apply their respective elastic forces to a common portion of the pressing mechanisms to generate the pressure.

Description

Technical Field

[0001] The present disclosure relates to a fixing device and an image forming apparatus. Background Art

[0002] Conventionally, there have been known a fixing device that sandwiches a recording material holding an unfixed image in a biting area and fixes the image to the recording material by heating or non-heating, and an image forming apparatus including such a fixing device. In addition, as such a fixing device, there has also been known a fixing device having a structure in which pressure in the biting area is obtained by the force of an elastic member such as a spring.

[0003] For example, in Japanese Unexamined Patent Application Publication No. 2018-155803, there is disclosed a fixing device including a compression coil spring that functions as a biasing unit for forming a fixing bite portion, and the fixing bite portion presses a fixing member and a pressurizing rotating body at a prescribed pressure to sandwich a recording medium.

[0004] In addition, in Japanese Unexamined Patent Application Publication No. 2019-020520, there is disclosed a pressurizing mechanism including a first pressurizing rod that holds a pressurizing member, and a second pressurizing rod that operates in synchronization with a pressurizing cam and applies a pressing force to the first pressurizing rod via a first biasing member, and a fixing bite is formed by the fixing member and the pressurizing member.

[0005] In addition, in Japanese Unexamined Patent Application Publication No. 2012-013914, there is disclosed a fixing bite load changing unit including: a support member as a support unit that supports a rotation shaft of a pressure roller; a spring as a biasing unit whose upper end is pressed against the support member; a pressure plate that supports a lower end of the spring; an elliptical pressing cam that abuts against a bottom surface of the pressure plate; and a load changing motor that drives the pressing cam to rotate. Summary of the Invention

[0006] In a fixing device or an image forming apparatus, the space where an elastic member can be provided is narrow, and a short elastic member having a large elastic constant is usually used. However, in particular, a short elastic member having a large elastic constant deteriorates over time and is liable to cause so-called elastic weakening.

[0007] An object of the present disclosure is to provide a fixing device and an image forming apparatus that suppress elastic weakening of an elastic member as compared with the case where fixing pressure is obtained by the force of one elastic member.

[0008] According to a first aspect of the present disclosure, there is provided a fixing device, wherein

[0009] the fixing device includes:

[0010] A pair of pressing members that apply pressure while sandwiching a recording material holding an unfixed image therebetween;

[0011] A plurality of pressing mechanisms that transmit force to at least one of the pair of pressing members to generate the above pressure; and

[0012] A plurality of elastic members that apply their respective elastic forces to a common portion of the pressing mechanisms to generate the above pressure.

[0013] According to the second aspect of the present disclosure, the elastic member is an elastic member that applies a force to a common portion common to the plurality of elastic members at one end,

[0014] The fixing device further includes an adjustment mechanism having one adjustment member. The one adjustment member contacts a common portion of the plurality of elastic members common to the other end of the elastic member relative to the one end, and adjusts the magnitude of the above pressure by adjusting the position of the adjustment member.

[0015] According to the third aspect of the present disclosure, at least one of the plurality of elastic members is a hollow member, and the plurality of elastic members are arranged coaxially with each other.

[0016] According to the fourth aspect of the present disclosure, the fixing device further includes a restraining member that contacts the inner periphery or the outer periphery of the hollow member and restrains the movement of the hollow member in a direction intersecting the axis.

[0017] According to the fifth aspect of the present disclosure, the restraining member is a cylindrical member that surrounds the outer periphery of the hollow member arranged inside the hollow members.

[0018] According to the sixth aspect of the present disclosure, the plurality of elastic members are arranged side by side with each other.

[0019] According to the seventh aspect of the present disclosure, the plurality of elastic members are hollow members, and the fixing device further includes a restraining member that contacts the inner periphery or the outer periphery of each hollow member and restrains the movement of each hollow member in a direction intersecting the axis.

[0020] According to the eighth aspect of the present disclosure, the restraining member has rod-shaped protrusions that enter the ends of the respective hollow members.

[0021] According to the ninth aspect of the present disclosure, there is provided an image forming apparatus, which includes:

[0022] An image forming unit that forms an unfixed image on a recording material that holds an image; and a fixing device that fixes the unfixed image on the recording material. The fixing device includes: a pair of pressing members that sandwich the recording material holding the unfixed image therebetween and apply pressure; a plurality of pressing mechanisms that transmit a force to at least one of the pair of pressing members to generate the pressure; and a plurality of elastic members that each apply an elastic force to a common portion of the pressing mechanisms to generate the pressure.

[0023] Effects of the Invention

[0024] According to the first aspect and the ninth aspect, compared with the case where the fixing pressure is obtained by the force of one elastic member, the weakening of the elasticity of the elastic member is suppressed.

[0025] According to the second aspect, a plurality of elastic members can be adjusted at one time.

[0026] According to the third aspect, compared with the case where they are not coaxially arranged, space saving is achieved.

[0027] According to the fourth aspect, compared with the case where the suppressing member is not provided, the posture of the coil spring is stable.

[0028] According to the fifth aspect, compared with the case where the cylindrical member is not provided, the structure is simple.

[0029] According to the sixth aspect, the thickness in the direction intersecting the parallel direction and the axial direction is suppressed.

[0030] According to the seventh aspect, compared with the case where the suppressing member is not provided, the posture of the coil spring is stable.

[0031] According to the eighth aspect, compared with the case where the rod-shaped protrusion is not provided, the structure is simple. Description of the Drawings

[0032] Figure 1 is a schematic configuration diagram of a printer equivalent to an embodiment of an image forming apparatus.

[0033] Figure 2 is a cross-sectional view showing the structure of the fixing device.

[0034] Figure 3 is a view showing the pressing mechanism disposed on the inner end side in the first embodiment.

[0035] Figure 4 is a view showing the pressing mechanism disposed on the front end side in the first embodiment.

[0036] Figure 5It is a perspective view showing the detailed structure of the coil spring and the like in the pressure applying mechanism included in the fixing device according to the first embodiment.

[0037] Figure 6 It is a side view showing the detailed structure of the coil spring and the like in the pressure applying mechanism included in the fixing device according to the first embodiment.

[0038] Figure 7 It is a perspective view showing the detailed structure of a coil spring and the like in a pressure applying mechanism included in the fixing device according to the second embodiment.

[0039] Figure 8 It is a side cross-sectional view showing the detailed structure of a coil spring and the like in a pressure applying mechanism included in the fixing device according to the second embodiment.

[0040] Figure 9 It is a perspective view showing the detailed structure of a coil spring and the like in a pressure applying mechanism included in the fixing device according to the third embodiment.

[0041] Figure 10 It is a side cross-sectional view showing the detailed structure of a coil spring and the like in a pressure applying mechanism included in the fixing device according to the third embodiment. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0043] Figure 1 This is a schematic structural diagram of a printer corresponding to one embodiment of the image forming apparatus.

[0044] Figure 1 The printer 10 shown is a monochrome printer, and an image signal representing an image generated outside the printer 10 is inputted via a signal cable or the like (not shown). The printer 10 is provided with a control unit 11 for controlling the operation of each component in the printer 10, and the image signal is inputted to the control unit 11. Then, in the printer 10, an image is formed based on the image signal under the control of the control unit 11.

[0045] The printer 10 has a paper tray 21 at the bottom thereof, and the paper P is stored in a stacked state on the paper tray 21. The paper tray 21 can be drawn out from the main body of the printer 10 to replenish the paper P. The paper tray 21 may include a plurality of paper trays 21 storing paper P of different sizes.

[0046] In each paper tray 21, as the medium described in the present disclosure, OHP sheets, plastic papers, envelopes, etc. can be accommodated instead of paper sheets P. In the present embodiment, the operation of the printer 10 is described in the case of accommodating the paper sheet P as the medium described in the present disclosure, but in the case of accommodating other media, the basic operation is the same.

[0047] The paper sheet P in the paper tray 21 is taken out by the pickup roller 22 and the separation roller 23 and sent to the standby roller 24 above. The paper sheet P that has reached the standby roller 24 is further conveyed upward after adjusting the conveyance timing.

[0048] In this printer 10, there is provided a cylindrical photosensitive member 12 that rotates in the direction shown by the arrow A. Around the photosensitive member 12, a charger 13, an exposure device 14, a developing device 15, a transfer device 16, and a photosensitive member cleaner 17 are arranged. The photosensitive member 12, the charger 13, the exposure device 14, the developing device 15, and the transfer device 16 together are an example of the image forming unit described in the present disclosure.

[0049] The charger 13 charges the surface of the photosensitive member 12, and the exposure device 14 exposes the surface of the photosensitive member 12 according to the image signal sent from the control unit 11 to form an electrostatic latent image. The electrostatic latent image is developed by the developing device 15 to form a toner image.

[0050] Here, the above-mentioned standby roller 24 sends out the paper sheet P in timing with the arrival of the toner image on the photosensitive member 12 at the transfer position facing the transfer device 16, so that the paper sheet P and the toner image reach the transfer position at the same time. Then, the toner image on the photosensitive member 12 is transferred onto the sent paper sheet P by the action of the transfer device 16. Thus, an unfixed toner image is formed on the paper sheet P.

[0051] The paper sheet P on which the unfixed toner image is formed further travels in the direction of the arrow B (upward) and is sent into the fixing device 18. The paper sheet P is heated and pressed in the fixing device 18, and the toner image is fixed on the paper sheet P. As a result, an image composed of the fixed toner image is formed on the paper sheet P. The paper sheet P heated and pressed by the fixing device 18 goes to the discharger 19. The paper sheet P going to the discharger 19 is further conveyed in the direction of the arrow D by the discharger 19 and discharged onto the paper discharge tray 20. The fixing device 18 corresponds to the first embodiment of the fixing device in the present disclosure.

[0052] Hereinafter, the structure of the fixing device 18 will be described in further detail.

[0053] Figure 2 It is a cross-sectional view showing the structure of the fixing device.

[0054] The fixing device 18 includes: having a generally roller-shaped appearance and along Figure 2A heating roller 31 extending in the depth direction; and a pressure roller 32 extending side by side with the heating roller 31 in the depth direction. The pressure roller 32 sandwiches the paper P between it and the heating roller 31 in a fixing area (also called a nipping area) and applies pressure, and conveys the paper P upward by rotation. Figure 2 The pressure roller 32 is a so-called rubber roller in which a rubber layer 34 is wound around a metal core 33. On the other hand, the heating roller 31 is an assembly assembled from a plurality of components, has a built-in heat source 35, and its outer peripheral surface is formed by a heating belt 36. The heating belt 36 moves in a cycle around the heating roller 31 to transport the heat of the heat source 35 to the fixing area. Figure 2 The paper P on which an unfixed image is formed passes between the heating roller 31 and the pressure roller 32, and thereby the image is fixed to the paper P. The combination of the heating roller 31 and the pressure roller 32 is an example of a pair of pressing members as described in the present disclosure.

[0055] In such a fixing device 18, the pressure in the fixing area is an important parameter that determines the image quality of the fixed image and the transport ability of the transported paper P. The pressure in the fixing area is called fixing pressure, nipping pressure, etc. In the fixing device 18 of the present embodiment, for example, the fixing pressure is obtained by pressing the heating roller 31 toward the pressure roller 32 side. The fixing device 18 is provided with a pressing mechanism for pressing the heating roller 31 toward the pressure roller 32 side.

[0056] A support member 37 for supporting the entire heating roller 31 as an assembly is incorporated in the heating roller 31, and the support member 37 protrudes toward both sides in the depth direction. The pressing mechanism applies forces to both ends of the protruding support member 37 respectively.

[0057] FIGS. Figure 2 and

[0058] Figure 3 are diagrams showing the pressing mechanism in the first embodiment. Figure 4 For example, a pair of pressing mechanisms 40 are arranged relative to the heating roller 31, and the pressing mechanisms 40 are distributively arranged at both ends in the depth direction of the figure.

[0059] FIG. Figure 3 shows the pressing mechanism 40 arranged on the inner end side in the figure of the heating roller 31, and Figure 4 shows the pressing mechanism 40 arranged on the front end side in the figure of the heating roller 31. These pressing mechanisms 40 are an example of the pressing mechanism as described in the present disclosure.

[0060] The pressing mechanism 40 includes: a lever 42 rotatable around a fulcrum 41; a coil spring 43 pressing the lever 42 at one end; a support plate 44 supporting the other end of the coil spring 43; and a support screw 45 which has a head 45a provided on the support plate 44 and a foot 45b screwed into a housing (not shown) to determine the position of the support plate 44.

[0061] The coil spring 43 supported by the support screw 45 and the support plate 44 presses the rod 42 upward in the figure. As a result, the rod 42 rotates counterclockwise in the figure around the fulcrum 41, and the rod 42 presses the support member 37 of the heating roller 31 toward the pressure roller 32. The above-mentioned fixing pressure is generated by this pressing force. Regarding the spring load of the coil spring 43 that generates the fixing pressure, by adjusting the screwing amount of the support screw 45 and the position of the support plate 44 for each product at the production site, the spring load is adjusted to an appropriate value.

[0062] The spring load is adjusted to a so-called full bite state in which the required maximum fixing pressure is generated in the fixing area. However, in the fixing device 18, it is not limited to always maintaining the full bite state. For example, in order to ensure the removability of the paper P when the paper P jams, or for example, in order to obtain the transportability of thick paper P, etc., it is also necessary to move the heating roller 31 away from the pressure roller 32 as needed compared to the full bite state. In the pressing mechanism 40, as a structure for moving the heating roller 31 away from the pressure roller 32, a cam 46 and a cam follower 47 are provided.

[0063] The cam 46 has a rotating shaft held on the housing side of the fixing device 18, and in Figure 4 the state shown, the cam surface is separated from the cam follower 47 and becomes the full bite state. When the cam 46 rotates from the Figure 4 state shown, the cam surface comes into contact with the cam follower 47 and presses the cam follower 47. The cam follower 47 is fixed to the rod 42, and the cam follower 47 is pressed by the cam surface, so that the rod 42 moves in a direction away from the pressure roller 32. As a result, the heating roller 31 pressed by the rod 42 also moves in a direction away from the pressure roller 32, and the fixing pressure decreases. When the cam surface presses the cam follower 47 to the maximum extent, the heating roller 31 is separated from the pressure roller 32, and it becomes easy to remove the paper P jammed due to paper clogging.

[0064] In this way, in the pressing mechanism 40, the fixing pressure is generated by the elastic force of the coil spring 43. However, when the spring constant of the coil spring 43 is large, the raw material of the coil spring 43 becomes a harder raw material, and it is easy for the elasticity of the coil spring 43 to weaken. In addition, when the spring constant of the coil spring 43 is large, a strong drive system is required as a drive system for the cam 46 for changing the fixing pressure, which leads to an increase in cost.

[0065] In response to this, in the pressing mechanism 40 included in the fixing device 18 of the present embodiment, research has been conducted on reducing the spring constant of the coil spring 43.

[0066] Figure 5 and Figure 6 are diagrams showing the detailed structure of the coil spring and the like in the pressing mechanism included in the fixing device of the first embodiment.Figure 5 Shows a perspective view, Figure 6 Shows a side view.

[0067] As described above, the pressing mechanism 40 includes a rod 42, a coil spring 43, a support plate 44, and a support screw 45.

[0068] The rod 42 presses the support member 37 of the heating roller 31 through the cutout portion 42a (see Figure 3 ), and receives the force of the coil spring 43 through the blocking portion 42b. In the pressing mechanism 40, a plurality (here, two as an example) of coil springs 43 having the same diameter are provided in parallel, and one end of each of these plurality of coil springs 43 presses the blocking portion 42b of the rod 42. In addition, the other end of each of the plurality of coil springs 43 is supported by the support plate 44. By sharing the force by the plurality of coil springs 43, the spring constant of each coil spring 43 becomes smaller. These plurality of coil springs 43 are an example of the plurality of elastic members described in the present disclosure.

[0069] Here, the spring specifications are compared between a comparative example having only one coil spring and the present embodiment having two coil springs 43.

[0070] When the required spring load is, for example, 86 N, in the comparative example, for example, a spring having an outer diameter of 13.2 mm, a wire diameter of 2.3 mm, and a spring constant of 19.4 N / mm is required. In contrast, in the case of the present embodiment, the 86 N spring load is shared by the two coil springs 43. Therefore, each coil spring 43 bears a spring load of 43 N. Moreover, as each coil spring 43, for example, a spring having an outer diameter of 11 mm, a wire diameter of 1.5 mm, and a spring constant of 4.7 N / mm is used, and the spring constant is significantly reduced compared to the comparative example.

[0071] As described above, the position of the support plate 44 is adjusted by the support screw 45, and the spring load of the coil spring 43 is adjusted by adjusting the position of the support plate 44. That is, by adjusting the position of one support plate 44 with one support screw 45, the spring load is adjusted for the plurality of coil springs 43 at once, so the adjustment is easy.

[0072] Posture holding rods 49 are provided on the support plate 44 and the blocking portion 42b of the rod 42, respectively. The posture holding rods 49 project inward of the coil spring 43 and enter the end portions of the coil spring 43. The posture holding rods 49 keep the posture of the coil spring 43 in contact with the inner circumference of the coil spring 43. That is, the posture holding rods 49 suppress the movement of the coil spring 43 in a direction intersecting the central axis of the coil spring 43. By holding the posture of the coil spring 43 with these posture holding rods 49, the force of the coil spring 43 is transmitted to the blocking portion 42b in the correct direction.

[0073] Next, a second embodiment of the fixing device will be described. The second embodiment is the same as the first embodiment except for the peripheral structure of the coil spring. Therefore, the following description focuses on the differences, and redundant descriptions are omitted.

[0074] Figure 7 and Figure 8 FIGS. are diagrams showing the detailed structure of a coil spring and the like in the pressing mechanism included in the fixing device according to the second embodiment. Figure 7 FIG. shows a perspective view, Figure 8 FIG. shows a side cross-sectional view.

[0075] The pressing mechanism 50 in the second embodiment includes a rod 52 similar to the pressing mechanism 40 in the first embodiment. In addition, in the case of the pressing mechanism 50 in the second embodiment, a support adjustment member 55 is provided, and the support adjustment member 55 corresponds to the combined structure of the support plate 44 and the support screw 45 of the pressing mechanism 40 in the first embodiment.

[0076] In the pressing mechanism 40 of the first embodiment, two coil springs 43 having the same diameter are provided in parallel. In contrast, in the pressing mechanism 50 of the second embodiment, a large-diameter coil spring 53 and a small-diameter coil spring 54 are coaxially arranged. In the second embodiment, space saving is achieved by such coaxial arrangement.

[0077] One end of each of the large-diameter coil spring 53 and the small-diameter coil spring 54 presses the blocking portion 52b of the rod 52 side by side. An intermediate member 57 through which the support adjustment member 55 passes is provided on the side of the coil springs 53 and 54 of the blocking portion 52b, and the coil springs 53 and 54 press the blocking portion 52b via the intermediate member 57. In addition, the other ends of the large-diameter coil spring 53 and the small-diameter coil spring 54 are supported by the plate-like portion 55a of the support adjustment member 55, and by adjusting the screwing amount of the support adjustment member 55, the spring loads of the large-diameter coil spring 53 and the small-diameter coil spring 54 are adjusted simultaneously. Here, as the elastic members arranged coaxially, they are not limited to coil springs, and as long as they can be arranged coaxially, they may be hollow members.

[0078] Here, in the above comparative example having only one coil spring and the present embodiment having the large-diameter coil spring 53 and the small-diameter coil spring 54, the spring specifications are compared.

[0079] As described above, the spring specifications in the comparative example are, for example, an outer diameter of 13.2 mm, a wire diameter of 2.3 mm, and a spring constant of 19.4 N / mm. In contrast, in the case of the present embodiment, the spring load of 86 N is shared by two coil springs 53 and 54, and each coil spring 53, 54 bears a spring load of 43 N, for example. Moreover, as the large-diameter coil spring 53, a spring with an outer diameter of 14.5 mm, a wire diameter of 1.7 mm, and a spring constant of 4.3 N / mm is used, for example. In addition, as the small-diameter coil spring 54, a spring with an outer diameter of 9.8 mm, a wire diameter of 1.5 mm, and a spring constant of 6.2 N / mm is used, for example.

[0080] Cylindrical posture holding walls 58 that project between the large-diameter coil spring 53 and the small-diameter coil spring 54 are provided on the plate-like portion 55a of the support adjustment member 55 and the intermediate member 57, respectively. The posture holding wall 58 contacts the inner periphery of the large-diameter coil spring 53 to hold the posture of the large-diameter coil spring 53. That is, the posture holding wall 58 suppresses the movement of the large-diameter coil spring 53 in a direction intersecting the central axis of the large-diameter coil spring 53, preventing contact between the large-diameter coil spring 53 and the small-diameter coil spring 54. The posture holding wall 58 may also contact the outer diameter of the large-diameter coil spring 53 to hold the posture, but in the case of the posture holding wall 58 that contacts the inner periphery of the large-diameter coil spring 53, contact between the large-diameter coil spring 53 and the small-diameter coil spring 54 is more reliably prevented.

[0081] In addition, in the second embodiment, the small-diameter coil spring 54 penetrates through the support adjustment member 55 inside, and the outer peripheral surface of the support adjustment member 55 contacts the inner periphery of the small-diameter coil spring 54, thereby holding the posture of the small-diameter coil spring 54.

[0082] Next, a third embodiment of the fixing device will be described. The third embodiment is the same as the second embodiment except for the difference in the structure for holding the posture of the coil spring. Therefore, the following description focuses on the differences and repetitive descriptions are omitted.

[0083] Figure 9 and Figure 10 is a diagram showing the detailed structure of a coil spring and the like in the pressing mechanism included in the fixing device of the third embodiment. Figure 9 shows a perspective view, Figure 10 shows a side cross-sectional view.

[0084] In the pressing mechanism 60 of the third embodiment, similar to the pressing mechanism 50 of the second embodiment, the small-diameter coil spring 54 holds its posture by penetrating through the support member 55 inside.

[0085] On the other hand, as a member for maintaining the posture of the large-diameter coil spring 53, in the third embodiment, a cylindrical posture holding cylinder 61 inserted between the small-diameter coil spring 54 and the large-diameter coil spring 53 is provided. The posture holding cylinder 61 surrounds the outer periphery of the small-diameter coil spring 54, and the outer peripheral surface contacts the inner periphery of the large-diameter coil spring 53. By providing such a posture holding cylinder 61, contact between the small-diameter coil spring 54 and the large-diameter coil spring 53 is prevented. In addition, the structure of the pressing mechanism 60 having the posture holding cylinder 61 is simple and the assemblability is excellent.

[0086] In addition, in the above description, a heat-pressing type fixing device is illustrated as an embodiment of the fixing device of the present disclosure, but the fixing device of the present disclosure may also be a fixing device that presses in a non-heated manner.

[0087] In addition, in the above description, as the pressing mechanism described in the present disclosure, a mechanism that presses the heating roller toward the pressure roller side is illustrated, but the pressing mechanism described in the present disclosure may also press the pressure roller toward the heating roller side.

[0088] In addition, in the above description, coil springs are illustrated as the plurality of elastic members described in the present disclosure, but the plurality of elastic members described in the present disclosure may also be springs other than coil springs, and may also be rubber. In addition, in the above description, compression springs are illustrated as the plurality of elastic members described in the present disclosure, but the plurality of elastic members described in the present disclosure may also be members that use traction force.

[0089] In addition, in the above description, a combination of a roller member and a belt member is illustrated as a pair of pressing members described in the present disclosure, but the pair of pressing members described in the present disclosure may also be a combination of roller members with each other, or may also be a combination of belt members with each other.

[0090] In addition, in the above description, a monochrome printer is illustrated as an embodiment of the image forming apparatus of the present disclosure, but the image forming apparatus of the present disclosure may also be a color printer, a copying machine, a facsimile machine, or a multifunction machine.

[0091] In addition, in the above description, an electrophotographic printer is illustrated as an embodiment of the image forming apparatus of the present disclosure, but the image forming apparatus of the present disclosure may also be a device using a method other than the electrophotographic method.

[0092] In addition, the above description is disclosed for the purpose of solving the problems described at the beginning of the Summary of the Invention, but it does not prevent the structure of the present disclosure from being diverted to other purposes in a form that does not solve the problem, and a mode in which the structure of the present disclosure is diverted in this way is also an embodiment of the present disclosure.

Claims

1. A fixing device, wherein, the fixing device includes: a pair of pressing members that sandwich a recording material holding an unfixed image therebetween and apply pressure; a pressing mechanism that transmits a force to at least one of the pair of pressing members to generate the pressure; and two elastic members that apply their respective elastic forces to the pressing mechanism to generate the pressure, at least one of the two elastic members being a hollow member, and the two elastic members being arranged coaxially with each other; a first pressed member, wherein first ends of the two elastic members are always in contact with the first pressed member in all regions of an activatable region where the pair of pressing members apply pressure to the recording material, and the first pressed member receives pressing from both of the two elastic members; and a second pressed member, wherein second ends of the two elastic members are always in contact with the second pressed member in all regions of the activatable region where the pair of pressing members apply pressure to the recording material, and the second pressed member receives pressing from both of the two elastic members, the first pressed member has a first posture holding wall that protrudes toward the second end side and enters between the two elastic members; the second pressed member has a second posture holding wall that protrudes toward the first end side to a position where it is not in contact with the first posture holding wall and enters between the two elastic members.

2. The fixing device according to claim 1, wherein, the two elastic members are elastic members that apply a force to a common portion common to the two elastic members at one end, the fixing device further includes an adjustment mechanism having one adjustment member that commonly contacts the two elastic members at the other ends of the two elastic members relative to the one end, and the magnitude of the pressure is adjusted by adjusting the position of the adjustment member.

3. An image forming apparatus, wherein, the image forming apparatus includes: an image forming unit that forms an unfixed image on a recording material holding an image; and the fixing device according to claim 1 or 2 that fixes the unfixed image on the recording material.

Images