Fixing device and image forming device

Abstract

The fixing device and image forming apparatus of the present invention suppress deformation of a supporting member compared to a case where a large rotational torque acts on the supporting member. A fixing device includes: a belt member; a pressure member forming a passage portion between the belt member and the pressure member for allowing recording medium to pass while applying pressure to the recording medium; a first member contacting the belt member on the inner side of the belt member and receiving a pressing force in one direction from the pressure member; a second member disposed on the inner side of the belt member and receiving a pressing force from the pressure member via the first member; and a supporting member, clamped between the first and second members, supporting the first member so that a region supporting the first member overlaps a region supported by the second member in one direction.

Description

Technical Field

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

[0002] Patent Document 1 describes that the heater holder is made of a heat-resistant resin, holds the ceramic heater, and also partially contacts the fixing belt to guide the fixing belt.

[0003] [Prior art literature]

[0004] [Patent Document]

[0005] [Patent Document 1] Japanese Patent No. 6172925 Summary of the Invention

[0006] [Problems to be solved by the invention]

[0007] A fixing device is sometimes provided with a belt member and a support member that supports the belt member from the inside. Here, when the support member is subjected to an external force, a rotational moment may act on the support member. If the rotational moment acting on the support member is large, the support member is likely to be deformed.

[0008] An object of the present invention is to suppress deformation of a support member compared to a case where a large rotational moment acts on the support member.

[0009] [Technical means to solve the problem]

[0010] The invention described in Technical Solution 1 is a fixing device, comprising: a belt member; a pressure member, which forms a passage portion between the belt member and the belt member for pressurizing the recording medium while allowing the recording medium to pass through; a first member, which contacts the belt member on the inner side of the belt member and receives a pressing force in one direction from the pressure member; a second member, which is arranged on the inner side of the belt member and receives a pressing force from the pressure member via the first member; and a supporting member, which is clamped by the first member and the second member to support the first member in such a manner that the area supporting the first member and the area supported by the second member overlap in the one direction.

[0011] The invention described in Technical Solution 2 is a fixing device according to Technical Solution 1, wherein the supporting member is arranged from the upstream side to the downstream side of the center of the passing portion in the moving direction of the belt member, and has an upstream side supporting portion that supports the first member on the upstream side and a downstream side supporting portion that supports the first member on the downstream side, the second member supports the first area of the upstream side supporting portion and the second area of the downstream side supporting portion, the upstream side supporting portion supports the first overlapping area of the first member that overlaps with the first area in the one direction, and the downstream side supporting portion supports the second overlapping area of the first member that overlaps with the second area in the one direction.

[0012] The invention described in claim 3 is the fixing device according to claim 2 , wherein the first overlapping area and the second overlapping area overlap with the passing portion in the one direction.

[0013] The invention described in Technical Solution 4 is a fixing device according to Technical Solution 2, and further includes a heating component, which is clamped by the belt component and the first component, and is arranged on the inner side of the first overlapping area and the second overlapping area in the moving direction. The heating component is in contact with the belt component to heat the belt component.

[0014] The invention described in Technical Solution 5 is a fixing device according to Technical Solution 1, wherein the first member is a heating member and is a portion that is arranged along the moving direction of the belt member and is supported by the supporting member in such a manner that the front end portion on the upstream side of the moving direction overlaps with the area of the supporting member supported by the second member.

[0015] The invention described in Technical Solution 6 is a fixing device according to Technical Solution 5, wherein the heating component is arranged from the upstream side to the downstream side of the center of the passing portion in the moving direction, and the length of the portion arranged from the center to the downstream side in the moving direction is shorter than the length of the portion arranged from the center to the upstream side in the moving direction.

[0016] The invention described in Technical Solution 7 is a fixing device according to Technical Solution 5, wherein the heating component is arranged from the upstream side to the downstream side of the center of the passing portion in the moving direction, and the length of the portion arranged from the center to the downstream side in the moving direction is longer than the length of the portion arranged from the center to the upstream side in the moving direction.

[0017] The invention described in Technical Solution 8 is an image forming device, comprising: an image forming mechanism for performing image formation on a recording medium; and a fixing device for fixing the image formed on the recording medium by the image forming mechanism to the recording medium, and the fixing device includes a fixing device according to any one of Technical Solutions 1 to 7.

[0018] [Effects of the Invention]

[0019] According to the invention of claim 1 , deformation of the support member can be suppressed compared to a case where a large rotational moment acts on the support member.

[0020] According to the invention of claim 2 , deformation of the portion connecting the upstream support portion and the downstream support portion in the support member can be suppressed compared to a case where the rotational moment acting on the upstream support portion and the rotational moment acting on the downstream support portion are large.

[0021] According to the invention of claim 3 , compared with a case where the first overlapping region and the second overlapping region do not overlap with the passage portion in one direction, the rotational moment acting on the upstream support portion and the rotational moment acting on the downstream support portion can be reduced.

[0022] According to the invention of claim 4 , compared with a case where the first member is a heating member, it is possible to suppress the surface of the recording medium on which the image is formed from coming into contact with the belt member before the image is fixed to the recording medium.

[0023] According to the invention of technical solution 5, compared with the case where the heating member is set to the upstream side of the moving direction of the belt member relative to the area where the supporting member is supported by the second member, the surface of the recording medium on which the image is formed can be prevented from contacting the belt member before the image is fixed to the recording medium.

[0024] According to the invention of technical solution 6, compared with the case where the length of the portion of the heating member extending from the center of the passing portion to the downstream side in the moving direction of the belt member is longer than the length of the portion extending from the center to the upstream side, the surface of the recording medium on which the image is formed can be prevented from contacting the belt member after the image is fixed to the recording medium.

[0025] According to the invention of technical solution 7, compared with the case where the length of the portion of the heating member extending from the center of the passing portion to the downstream side in the moving direction is shorter than the length of the portion extending from the center to the upstream side, the recording medium on which the image is fixed is easily peeled off from the member.

[0026] According to the invention of claim 8 , deformation of the support member can be suppressed compared to a case where the rotational moment acting on the support member is large. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a diagram showing the overall structure of an image forming apparatus.

[0028] Figure 2 It is a diagram showing the structure of the fixing device.

[0029] Figure 3 It is from Figure 2 A three-dimensional diagram when observing the supporting structure in the direction of arrow III.

[0030] Figure 4 yes Figure 2 Magnified view of area E.

[0031] Figure 5 It is a diagram showing a comparative example.

[0032] Figure 6 It is a diagram showing the configuration of a fixing device as a modified example.

[0033] Figure 7 It is a diagram showing the configuration of a fixing device as a modified example.

[0034] Figure 8 It is a diagram showing the configuration of a fixing device as a modified example.

[0035] Figure 9 It is a diagram showing the configuration of a fixing device as a modified example.

[0036] [Explanation of Reference Numerals]

[0037] 1: Image forming device

[0038] 10: Image forming unit

[0039] 40: Fixing device

[0040] 41: Fusing belt module

[0041] 46: Pressure roller

[0042] 420: Heating component

[0043] 430: Support frame

[0044] 440: With supporting structure DETAILED DESCRIPTION

[0045] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0046] <Description of Image Forming Apparatus>

[0047] Figure 1 1 is a diagram showing the overall structure of the image forming apparatus 1. Figure 1This is a diagram when the image forming apparatus 1 is viewed from the front side (front surface side) of the image forming apparatus 1 .

[0048] The image forming apparatus 1 is a so-called tandem color printer.

[0049] The image forming apparatus 1 includes an image forming unit 10 as an example of an image forming mechanism. The image forming unit 10 forms an image on a paper P as an example of a recording medium based on image data of each color.

[0050] Furthermore, the image forming apparatus 1 is provided with a control unit 30 and an image processing unit 35 .

[0051] The control unit 30 controls each functional unit provided in the image forming apparatus 1 .

[0052] The image processing unit 35 performs image processing on image data from the personal computer (PC) 3 or the image reading device 4 .

[0053] The image forming section 10 is provided with four image forming units 11Y, 11M, 11C, and 11K (hereinafter also simply collectively referred to as “image forming units 11 ”) arranged in parallel at regular intervals.

[0054] Each image forming unit 11 has the same configuration except for the toner stored in a developing unit 15 (described later). Each image forming unit 11 forms a toner image (image) of yellow (Y), magenta (M), cyan (C), and black (K).

[0055] Each image forming unit 11 is provided with a photosensitive drum 12 , a charger 200 for charging the photosensitive drum 12 , and a light emitting diode (LED) print head (LPH) 300 for exposing the photosensitive drum 12 .

[0056] The photosensitive drum 12 is charged by the charger 200 . Furthermore, the photosensitive drum 12 is exposed by the LPH 300 , and an electrostatic latent image is formed on the photosensitive drum 12 .

[0057] Furthermore, each image forming unit 11 is provided with a developing device 15 for developing the electrostatic latent image formed on the photosensitive drum 12 and a cleaner (not shown) for cleaning the surface of the photosensitive drum 12 .

[0058] In addition, the image forming unit 10 is provided with an intermediate transfer belt 20 and a primary transfer roller 21. The intermediate transfer belt 20 is used to transfer the toner images of each color formed on the photosensitive drum 12, and the primary transfer roller 21 transfers the toner images of each color formed on the photosensitive drum 12 to the intermediate transfer belt 20 in sequence (primary transfer).

[0059] In addition, the image forming unit 10 is provided with a secondary transfer roller 22 and a fixing device 40. The secondary transfer roller 22 transfers (secondary transfers) the toner image transferred to the intermediate transfer belt 20 to the paper P in a unified manner, and the fixing device 40 fixes the toner image transferred to the paper P to the paper P.

[0060] The fixing device 40 is provided with a fixing belt module 41 including a heating member and a pressure roller 46 .

[0061] The fixing belt module 41 is arranged on the left side of the paper conveyance path R1 in the figure. The pressure roller 46 is arranged on the right side of the paper conveyance path R1 in the figure. The pressure roller 46 is pressed against the fixing belt module 41.

[0062] The fixing belt module 41 includes a film-shaped fixing belt 411 that comes into contact with the paper P.

[0063] The fixing belt 411, an example of a belt member, includes, for example, a release layer, located on the outermost layer and in contact with the paper P; an elastic layer, located on one inner side of the release layer; and a base layer, which supports the elastic layer. The fixing belt 411 is formed endlessly and circulates counterclockwise in the figure. Furthermore, the fixing belt 411 is formed along the axial direction.

[0064] The fixing belt 411 contacts the paper P conveyed from below in the figure. The portion of the fixing belt 411 that contacts the paper P moves together with the paper P. The fixing belt 411 and the pressure roller 46 nip the paper P, and pressurize and heat the paper P.

[0065] Furthermore, in the fixing belt module 41 , a heating member (described later) for heating the fixing belt 411 is provided inside the fixing belt 411 .

[0066] A pressure roller 46 , an example of a pressure member, is located on the right side of the paper transport path R1 in the drawing. The pressure roller 46 is pressed against the outer peripheral surface 411B of the fixing belt 411 , and applies pressure to the paper P passing between the fixing belt 411 and the pressure roller 46 (the paper P passing through the paper transport path R1 ).

[0067] The pressure roller 46 is rotated clockwise in the figure by a motor (not shown). When the pressure roller 46 rotates clockwise, the fixing belt 411 receives a driving force from the pressure roller 46 and rotates counterclockwise.

[0068] In the image forming apparatus 1 , the image processing section 35 performs image processing on image data from the PC 3 or the image reading device 4 , and the image data subjected to image processing is supplied to each image forming unit 11 .

[0069] For example, in the black (K) image forming unit 11K, the photosensitive drum 12 is charged by the charger 200 while rotating in the direction of arrow A, and is exposed by the LPH 300 that emits light based on image data sent from the image processing unit 35 .

[0070] As a result, an electrostatic latent image related to a black (K) image is formed on the photosensitive drum 12. The electrostatic latent image formed on the photosensitive drum 12 is then developed by the developer 15, thereby forming a black (K) toner image on the photosensitive drum 12.

[0071] Similarly, in the image forming units 11Y, 11M, and 11C, toner images of yellow (Y), magenta (M), and cyan (C) are formed.

[0072] The toner images of the respective colors formed by the image forming units 11 are sequentially electrostatically attracted by the primary transfer rollers 21 to the intermediate transfer belt 20 moving in the direction of arrow B, thereby forming a toner image in which the toners of the respective colors overlap on the intermediate transfer belt 20 .

[0073] The toner image formed on the intermediate transfer belt 20 is transported to the location of the secondary transfer roller 22 (secondary transfer section T) as the intermediate transfer belt 20 moves. Then, depending on the timing of the toner image being transported to the secondary transfer section T, the paper P is supplied from the paper storage section 1B to the secondary transfer section T.

[0074] In the secondary transfer portion T, the toner images on the intermediate transfer belt 20 are electrostatically transferred collectively to the conveyed paper P by a transfer electric field formed by the secondary transfer roller 22 .

[0075] Thereafter, the paper P onto which the toner image is electrostatically transferred is peeled off from the intermediate transfer belt 20 and conveyed to the fixing device 40 .

[0076] In the fixing device 40 , the fixing belt module 41 and the pressure roller 46 nip the paper P. Specifically, the paper P is nipped by the fixing belt 411 circulating counterclockwise and the pressure roller 46 rotating clockwise.

[0077] Thus, the paper P is pressed and heated, and the toner image on the paper P is fixed to the paper P. Then, the paper P after fixing is conveyed to the paper loading portion 1E by the discharge rollers 500 .

[0078] <Structure of the fixing unit>

[0079] Next, the structure of the fixing device 40 will be described.

[0080] Figure 2 It is a diagram showing the structure of the fixing device 40 .

[0081] The fixing belt module 41 is provided with a fixing belt 411 for fixing the toner image to the paper P. The fixing belt 411 is pressed against the surface of the paper P on which the toner image is formed.

[0082] The pressure roller 46 is pressed against the outer peripheral surface 411B of the fixing belt 411 , and presses the paper P passing between the fixing belt 411 and the pressure roller 46 .

[0083] Specifically, the pressure roller 46 is arranged in contact with the outer peripheral surface 411B of the fixing belt 411, and forms a nip N between the pressure roller 46 and the fixing belt 411, where the paper P passes while being pressed. Here, the nip N can be understood as a passage portion where the paper P passes while being pressed.

[0084] In this embodiment, the paper P is heated and pressurized while the paper passes through the nip N, so that the toner image is fixed to the paper P.

[0085] A heating member 420 for heating the fixing belt 411 is provided inside the fixing belt 411 .

[0086] The heating member 420, as an example of a first member, is formed in a plate shape and is arranged along the moving direction and axial direction of the fixing belt 411. More specifically, the heating member 420 is arranged from the upstream side to the downstream side of the center of the clamping portion N in the moving direction of the fixing belt 411. The heating member 420 is in contact with the fixing belt 411 and supplies heat to the fixing belt 411 to heat the fixing belt 411. The portion of the fixing belt 411 that is in contact with the heating member 420 becomes flat along the heating member 420. In addition, in this embodiment, the pressure roller 46 is pressed against the heating member 420 via the fixing belt 411. Therefore, the heating member 420 receives a pressing force in the direction of the arrow D in the figure from the pressure roller 46. In addition, even if the heating member 420 is set to be pressed against the pressure roller 46 via the fixing belt 411, the heating member 420 receives a pressing force in the direction of the arrow D in the figure from the pressure roller 46.

[0087] The fixing belt module 41 is also provided with a belt support member 440 that supports the fixing belt 411 from the inside. The belt support member 440, an example of a support member, is provided from upstream to downstream of the center of the nip portion N in the moving direction of the fixing belt 411. The belt support member 440 is provided with an upstream support portion 441 and a downstream support portion 445.

[0088] The upstream support portion 441 is provided upstream of the center of the nip portion N in the moving direction of the fixing belt 411. Furthermore, the upstream support portion 441 is provided along the axial direction of the fixing belt 411. The upstream support portion 441 contacts a portion of the inner circumferential surface 411A of the fixing belt 411 and supports the fixing belt 411 from the inside.

[0089] The downstream support portion 445 is provided downstream of the center of the nip portion N in the moving direction of the fixing belt 411. Furthermore, the downstream support portion 445 is provided along the axial direction of the fixing belt 411. The downstream support portion 445 contacts a portion of the inner circumferential surface 411A of the fixing belt 411 and supports the fixing belt 411 from the inside.

[0090] Furthermore, the fusing belt module 41 is provided with a support frame 430, an example of a second member. The support frame 430 is arranged along the axial direction of the fusing belt 411. The support frame 430 is positioned inside the fusing belt 411 and supports the belt support member 440. Furthermore, the support frame 430 is supported by a support mechanism (not shown) provided axially outside the fusing belt 411, thereby being positioned relative to the fusing belt module 41. The support frame 430 is made of, for example, metal.

[0091] The support frame 430 is provided with an upstream frame portion 431 and a downstream frame portion 432 .

[0092] The upstream-side frame portion 431 is provided upstream of the center of the nip portion N in the moving direction of the fixing belt 411 . The upstream-side frame portion 431 supports the upstream-side support portion 441 .

[0093] The downstream-side frame portion 432 is provided on the downstream side of the center of the nip portion N in the moving direction of the fixing belt 411 . The downstream-side frame portion 432 supports the downstream-side support portion 445 .

[0094] Furthermore, a sensor 450 is provided in the fixing belt module 41. The sensor 450 is disposed inside the support frame 430. The sensor 450 is controlled by the control unit 30. The sensor 450 is, for example, a temperature sensor that detects the temperature of the fixing belt module 41.

[0095] Figure 3 It is from Figure 2 A three-dimensional diagram when the support member 440 is observed in the direction of arrow III.

[0096] In the present embodiment, a recessed portion 440A having a notch is formed in the belt support member 440. In the present embodiment, the heating member 420 is positioned relative to the belt support member 440 by fitting the heating member 420 into the notch of the recessed portion 440A.

[0097] Furthermore, a plurality of openings H are provided in the recess 440A of the belt support member 440. An opening is formed in each of the plurality of openings H. This reduces the area of the portion of the heating member 420 that contacts the belt support member 440 compared to a case where no opening is formed in the recess 440A of the belt support member 440.

[0098] Figure 4 yes Figure 2 The enlarged view of region E. Figure 4 In the illustrated configuration, the configuration of the sensor 450 is omitted.

[0099] The upstream support portion 441 of the belt support member 440 is provided with a first protruding portion 442 , a second protruding portion 443 , and a connecting portion 444 .

[0100] The first protrusion 442 is provided upstream of the second protrusion 443 in the moving direction of the fixing belt 411. The first protrusion 442 protrudes toward the inner peripheral surface 411A of the fixing belt 411. More specifically, the first protrusion 442 protrudes upward in the figure.

[0101] The second protrusion 443 protrudes toward the inner peripheral surface 411A of the fixing belt 411. More specifically, the second protrusion 443 protrudes toward the upper side in the figure.

[0102] The first protrusion 442 is provided to extend upward in the figure relative to the second protrusion 443. More specifically, the protrusion length of the first protrusion 442 is longer than the protrusion length of the second protrusion 443 and shorter than twice the protrusion length of the second protrusion 443.

[0103] The connecting portion 444 connects the first protrusion 442 and the second protrusion 443 .

[0104] Furthermore, the downstream support portion 445 of the present embodiment is provided with a first protruding portion 446 , a second protruding portion 447 , and a connecting portion 448 .

[0105] The first protrusion 446 is provided on the downstream side of the second protrusion 447 in the direction of movement of the fixing belt 411. The first protrusion 446 protrudes toward the inner circumferential surface 411A of the fixing belt 411. More specifically, the first protrusion 446 protrudes upward in the figure. Furthermore, the first protrusion 446 is provided with a rib 446A extending upstream in the direction of movement of the fixing belt 411.

[0106] The second protrusion 447 protrudes toward the inner peripheral surface 411A of the fixing belt 411. More specifically, the second protrusion 447 protrudes upward in the figure. A rib 447A extending downstream in the moving direction of the fixing belt 411 is provided on the second protrusion 447.

[0107] The first protrusion 446 is provided to extend upward in the figure relative to the second protrusion 447. More specifically, the protruding length of the first protrusion 446 is longer than the protruding length of the second protrusion 447 and shorter than twice the protruding length of the second protrusion 447.

[0108] The connecting portion 448 connects the first protrusion 446 and the second protrusion 447 .

[0109] Inside the fixing belt 411, the upstream frame portion 431 of the support frame 430 supports the connecting portion 444 of the upstream support portion 441. Here, the upstream frame portion 431 is positioned between the first protrusion 442 and the second protrusion 443 of the upstream support portion 441. Furthermore, gaps are formed between the first protrusion 442 and the upstream frame portion 431, and between the second protrusion 443 and the upstream frame portion 431.

[0110] Furthermore, inside the fixing belt 411, the downstream frame portion 432 of the support frame 430 supports the connecting portion 448 of the downstream support portion 445. Here, the downstream frame portion 432 is sandwiched between the first protrusion 446 and the second protrusion 447 of the downstream support portion 445. More specifically, the downstream frame portion 432 is sandwiched between the rib 446A of the first protrusion 446 and the rib 447A of the second protrusion 447.

[0111] The upstream support portion 441 also supports the heating member 420, which is fitted into the recess 440A of the belt support member 440. More specifically, the upstream support portion 441 supports the front end portion of the heating member 420 on the upstream side in the direction of movement of the fixing belt 411. Hereinafter, the front end portion of the heating member 420 on the upstream side in the direction of movement of the fixing belt 411 is referred to as the upstream end portion 420A of the heating member 420.

[0112] The downstream support portion 445 also supports the heating member 420, which is fitted into the recess 440A of the belt support member 440. More specifically, the downstream support portion 445 supports the front end portion of the heating member 420 on the downstream side in the moving direction of the fixing belt 411. Hereinafter, the front end portion of the heating member 420 on the downstream side in the moving direction of the fixing belt 411 is referred to as the downstream end portion 420B of the heating member 420.

[0113] Here, in this embodiment, the belt support member 440 receives a pressing force from the pressure roller 46 via the heating member 420. More specifically, the upstream support portion 441 of the belt support member 440 receives a pressing force F1 from the upstream end 420A of the heating member 420. Furthermore, the downstream support portion 445 of the belt support member 440 receives a pressing force F2 from the downstream end 420B of the heating member 420. Both the pressing force F1 and the pressing force F2 act in the direction D in which the heating member 420 receives the pressing force from the pressure roller 46.

[0114] Furthermore, in this embodiment, as described above, the support frame 430 supports the belt support member 440, and the support frame 430 is subjected to the pressing force of the pressure roller 46 via the belt support member 440 and the heating member 420. In this case, the belt support member 440 is subjected to a reaction force from the support frame 430. More specifically, the upstream support portion 441 of the belt support member 440 is subjected to a reaction force F3 from the upstream frame portion 431. Furthermore, the downstream support portion 445 of the belt support member 440 is subjected to a reaction force F4 from the downstream frame portion 432.

[0115] Figure 5 It is a diagram showing a comparative example.

[0116] In the comparative example, the area where the belt support member 440 supports the heating member 420 does not overlap with the area where the belt support member 440 is supported by the support frame 430. More specifically, the area S1 where the upstream support portion 441 of the belt support member 440 supports the upstream end portion 420A of the heating member 420 and the area K1 where the upstream support portion 441 is supported by the upstream frame portion 431 do not overlap in the direction D in which the pressing force of the pressure roller 46 is exerted. Furthermore, the area S2 where the downstream support portion 445 of the belt support member 440 supports the downstream end portion 420B of the heating member 420 and the area K2 where the downstream support portion 445 is supported by the downstream frame portion 432 do not overlap in the direction D in which the pressing force of the pressure roller 46 is exerted.

[0117] In this case, the upstream support portion 441 receives a pressing force F1 from the upstream end portion 420A of the heating element 420 and a reaction force F3 from the upstream frame portion 431, resulting in a rotational moment acting on the upstream support portion 441. More specifically, a rotational moment M1 acts on the upstream support portion 441 with the portion of the upstream support portion 441 supported by the upstream frame portion 431 as the center of rotation. Furthermore, the downstream support portion 445 receives a pressing force F2 from the downstream end portion 420B of the heating element 420 and a reaction force F4 from the downstream frame portion 432, resulting in a rotational moment acting on the downstream support portion 445. More specifically, a rotational moment M2 acts on the downstream support portion 445 with the portion of the downstream support portion 445 supported by the downstream frame portion 432 as the center of rotation. Furthermore, when the rotational moment M1 acting on the upstream support portion 441 and the rotational moment M2 acting on the downstream support portion 445 are large, the portion connecting the upstream support portion 441 and the downstream support portion 445 in the belt support member 440 may be deformed.

[0118] Here, in this embodiment, similarly to the comparative example, the following configuration is also adopted: Figure 4 As shown, the upstream support portion 441 receives a pressing force F1 from the heating member 420 and a reaction force F3 from the upstream frame portion 431, so that a rotational moment can act on the upstream support portion 441. Furthermore, the downstream support portion 445 receives a pressing force F2 from the heating member 420 and a reaction force F4 from the downstream frame portion 432, so that a rotational moment can act on the downstream support portion 445.

[0119] However, in this embodiment, the region where the belt support member 440 supports the heating member 420 overlaps with the region where the belt support member 440 is supported by the support frame 430 , thereby reducing the rotational moment acting on the belt support member 440 .

[0120] More specifically, in this embodiment, the area S1 where the upstream support portion 441 supports the upstream end portion 420A of the heating member 420 overlaps with the area K1 where the upstream support portion 441 is supported by the upstream frame portion 431 in the direction D in which the pressing force of the pressure roller 46 is exerted. In other words, the upstream support portion 441 supports an area L1 of the heating member 420 that overlaps with the area K1 in the direction D in which the pressing force of the pressure roller 46 is exerted. Furthermore, the area S2 where the downstream support portion 445 supports the heating member 420 overlaps with the area K2 where the downstream support portion 445 is supported by the downstream frame portion 432 in the direction D in which the pressing force of the pressure roller 46 is exerted. In other words, the downstream support portion 445 supports an area L2 of the heating member 420 that overlaps with the area K2 in the direction D in which the pressing force of the pressure roller 46 is exerted. Hereinafter, the area L1 will be referred to as the first overlapping area L1. Furthermore, the area L2 will be referred to as the second overlapping area L2. The area S1 is an example of a first area. Furthermore, the area S2 is an example of the second area.

[0121] In this case, the portion of the upstream support portion 441 receiving the pressing force F1 from the upstream end portion 420A of the heating member 420 and the portion of the upstream support portion 441 receiving the reaction force F3 from the upstream frame portion 431 overlap in the direction D in which the pressing force of the pressure roller 46 is exerted. The rotational torque acting on the upstream support portion 441 decreases in accordance with the amount of this overlap.

[0122] Furthermore, the portion of the downstream support portion 445 receiving the pressing force F2 from the downstream end portion 420B of the heating member 420 and the portion of the downstream support portion 445 receiving the reaction force F4 from the downstream frame portion 432 overlap in the direction D in which the pressing force of the pressure roller 46 is exerted. The rotational torque acting on the downstream support portion 445 decreases in accordance with the amount of this overlap.

[0123] Furthermore, in this embodiment, the heating member 420 is supported by the belt supporting member 440 so that the front end portion on the upstream side in the moving direction of the fixing belt 411 overlaps with the region of the belt supporting member 440 supported by the supporting frame 430. In other words, in this embodiment, the upstream end portion 420A of the heating member 420 is supported by the upstream supporting portion 441, but the supported upstream end portion 420A overlaps with the region K1 supported by the upstream supporting portion 441 by the upstream frame portion 431.

[0124] For example, if the heating member 420 is provided up to a portion 420X upstream of the region K1 where the upstream support portion 441 is supported by the upstream frame portion 431 in the moving direction of the fixing belt 411, the flat portion 411X of the fixing belt 411 along the heating member 420 also becomes longer. In this case, the portion of the fixing belt 411 upstream of the nip portion N in the moving direction of the fixing belt 411 approaches the transport path of the paper P.

[0125] In contrast, if the upstream end portion 420A of the heating member 420 is not positioned upstream of the region K1 where the upstream support portion 441 is supported by the upstream frame portion 431 in the moving direction of the fixing belt 411, as in the present embodiment, the flat portion of the fixing belt 411 becomes shorter. In this case, the portion of the fixing belt 411 upstream of the nip portion N in the moving direction of the fixing belt 411 becomes further away from the transport path of the paper P.

[0126] <Variation 1>

[0127] Next, a modified example of the fixing device 40 will be described.

[0128] Figure 6 1 is a diagram showing a configuration of a fixing device 40 as a modified example. Components identical to those described above are denoted by the same reference numerals.

[0129] exist Figure 6 In the structure shown, the positional relationship between the first overlapping area L1 and the second overlapping area L2 and the clamping portion N is the same as Figure 4 More specifically, in Figure 6 In the illustrated configuration, the first overlapping region L1 and the second overlapping region L2 are located outside the nip N in the moving direction of the fixing belt 411 . That is, the first overlapping region L1 and the second overlapping region L2 do not overlap the nip N in the direction D in which the pressing force of the pressure roller 46 is applied.

[0130] Even with this configuration, the rotational moment acting on the upstream support portion 441 decreases as the first overlapping region L1 exists. Also, the rotational moment acting on the downstream support portion 445 decreases as the second overlapping region L2 exists.

[0131] Furthermore, in Figure 4 In the illustrated configuration, the first overlapping region L1 and the second overlapping region L2 overlap the nip portion N in the direction D in which the pressing force of the pressure roller 46 acts.

[0132] In this case, the pressing force from the pressure roller 46 on the heating member 420 is more easily dispersed to the upstream end portion 420A and the downstream end portion 420B than in a case where the first overlapping region L1 and the second overlapping region L2 are located further outward from the nip portion N in the moving direction of the fixing belt 411. In other words, the pressing force from the pressure roller 46 on the heating member 420 is more easily dispersed to the first overlapping region L1 and the second overlapping region L2 of the heating member 420.

[0133] <Variation 2>

[0134] Next, a modification (modification 2) of the fixing device 40 will be described.

[0135] Figure 7 1 is a diagram showing a configuration of a fixing device 40 as a modified example. Components identical to those described above are denoted by the same reference numerals.

[0136] In this modified example, the length of the portion of the heating member 420 extending from the center NC of the nip N to the upstream side in the direction of movement of the fixing belt 411 is denoted as length 420LA. Furthermore, the length of the portion of the heating member 420 extending from the center NC of the nip N to the downstream side in the direction of movement of the fixing belt 411 is denoted as length 420LB. Length 420LB is shorter than length 420LA.

[0137] In the case described, Figure 4 Compared to the configuration shown (see the dotted line portion in the figure), the flat portion of the fixing belt 411 along the heating member 420 is shortened by the amount of the shortened length 420LB. Therefore, the portion of the fixing belt 411 downstream of the nip portion N in the direction of movement of the fixing belt 411 is further away from the transport path of the paper P.

[0138] <Variation 3>

[0139] Next, a modification (modification 3) of the fixing device 40 will be described.

[0140] Figure 8 1 is a diagram showing a configuration of a fixing device 40 as a modified example. Components identical to those described above are denoted by the same reference numerals.

[0141] In this modified example, the length of the portion of the heating member 420 extending from the center NC of the nip N to the upstream side in the direction of movement of the fixing belt 411 is denoted as length 420LA. Furthermore, the length of the portion of the heating member 420 extending from the center NC of the nip N to the downstream side in the direction of movement of the fixing belt 411 is denoted as length 420LB. Length 420LB is longer than length 420LA.

[0142] In the case described, Figure 4 Compared to the configuration shown (see the dotted line portion in the figure), the flat portion of the fixing belt 411 along the heating member 420 is longer by the amount of the increase in length 420LB. In other words, after the image is fixed to the paper P, the section in which the paper P is cooled while being conveyed along the fixing belt 411 is longer.

[0143] <Variation 4>

[0144] Next, a modification (modification 4) of the fixing device 40 will be described.

[0145] Figure 9 1 is a diagram showing a configuration of a fixing device 40 as a modified example. Components identical to those described above are denoted by the same reference numerals.

[0146] exist Figure 9 In the illustrated configuration, a support plate 470 that supports the heating member 420 is provided in the fixing belt module 41 .

[0147] The support plate 470, an example of a first member, is formed in a plate shape and is arranged along the moving direction and axial direction of the fixing belt 411. The support plate 470 is made of, for example, a resin material. Alternatively, the support plate 470 may be made of, for example, a metal material. A first surface 470A of the support plate 470 is supported by the upstream support portion 441 and the downstream support portion 445 of the belt support member 440. Furthermore, a second surface 470B of the support plate 470, opposite to the first surface 470A, supports the heating member 420.

[0148] In addition, the heating member 420 is sandwiched between the support plate 470 and the fixing belt 411 , and is not directly supported by the belt supporting member 440 .

[0149] Here, in Figure 9 In the illustrated configuration, the belt support member 440 receives a pressing force from the pressure roller 46 via the support plate 470 and the heating member 420. More specifically, the upstream support portion 441 of the belt support member 440 receives a pressing force F5 from the support plate 470. Furthermore, the downstream support portion 445 of the belt support member 440 receives a pressing force F6 from the support plate 470. Furthermore, as described above, the upstream support portion 441 receives a reaction force F3 from the upstream frame portion 431, and the downstream support portion 445 receives a reaction force F4 from the downstream frame portion 432.

[0150] In addition, Figure 9In the illustrated configuration, the area where the belt support member 440 supports the support plate 470 overlaps with the area where the belt support member 440 is supported by the support frame 430. More specifically, the area U1 where the upstream support portion 441 of the belt support member 440 supports the support plate 470 overlaps with the area K1 where the upstream support portion 441 is supported by the upstream frame portion 431 in the direction D in which the pressing force of the pressure roller 46 is exerted. In other words, the upstream support portion 441 supports an area X1 of the support plate 470 that overlaps with the area K1 in the direction D in which the pressing force of the pressure roller 46 is exerted. Furthermore, the area U2 where the downstream support portion 445 of the belt support member 440 supports the support plate 470 overlaps with the area K2 where the downstream support portion 445 is supported by the downstream frame portion 432 in the direction D in which the pressing force of the pressure roller 46 is exerted. In other words, the downstream support member 445 supports an area X2 of the support plate 470 that overlaps with the area K2 in the direction D in which the pressing force of the pressure roller 46 is exerted. Furthermore, region X1 can be understood as the first overlapping region. Furthermore, region X2 can be understood as the second overlapping region. Furthermore, region U1 is an example of the first region. Furthermore, region U2 is an example of the second region.

[0151] In this case, the portion of the upstream support portion 441 receiving the pressing force F5 from the support plate 470 and the portion of the upstream support portion 441 receiving the reaction force F3 from the upstream frame portion 431 overlap in the direction D in which the pressing force of the pressure roller 46 is exerted. The rotational torque acting on the upstream support portion 441 decreases in accordance with the amount of this overlap.

[0152] Furthermore, the portion of the downstream support portion 445 receiving the pressing force F6 from the support plate 470 and the portion of the downstream support portion 445 receiving the reaction force F4 from the downstream frame portion 432 overlap in the direction D in which the pressing force of the pressure roller 46 is exerted. The rotational torque acting on the downstream support portion 445 decreases in accordance with the amount of this overlap.

[0153] In addition, Figure 9 In the structure shown, the heating member 420 is provided inside the region X1 and the region X2 in the moving direction of the fixing belt 411. Figure 4 Compared with the illustrated configuration, the heating member 420 is provided shorter.

[0154] In the case described, Figure 4 Compared to the configuration shown (see the dotted line portion in the figure), the flat portion of the fixing belt 411 along the heating member 420 is shortened by the amount of the shortened heating member 420. Therefore, in the moving direction of the fixing belt 411, the portion of the fixing belt 411 outside the nip portion N is away from the conveyance path of the paper P.

[0155] Furthermore, in Figure 9 In the illustrated configuration, the regions X1 and X2 overlap with the nip N in the direction D in which the pressing force of the pressure roller 46 is exerted. However, a configuration may be employed in which the regions X1 and X2 are provided outside the nip N in the direction of movement of the fixing belt 411. In other words, the regions X1 and X2 do not necessarily overlap with the nip N in the direction D in which the pressing force of the pressure roller 46 is exerted.

[0156] In addition, Figure 9 In the structure shown, the length of the portion of the support plate 470 extending from the center of the clamping portion N to the downstream side in the moving direction of the fixing belt 411 can be made longer than the length of the portion extending from the center of the clamping portion N to the upstream side, or can be made shorter than the length of the portion extending from the center of the clamping portion N to the upstream side.

[0157] In addition, the present invention is described in terms of an electronic photographic image forming apparatus, but is not limited to electronic photographic image forming apparatuses. For example, it can also be applied to an inkjet image forming apparatus, etc. The inkjet image forming apparatus maintains an undried image (unfixed ink image) formed by ink and contacts the conveyed paper to fix the unfixed ink image on the paper.

Claims

1. A fixing device, characterized in that: include: with components; a pressing member forming a passage portion for allowing the recording medium to pass therethrough while pressing the recording medium, between the pressing member and the belt member; a first member disposed inside the belt member and receiving a pressing force in one direction from the pressing member; a second member disposed inside the belt member and receiving a pressing force from the pressing member via the first member; as well as a supporting member, which is clamped by the first member and the second member so as to support the first member in such a manner that a region supporting the first member and a region supported by the second member overlap in the one direction, the supporting member being arranged from upstream to downstream relative to the center of the passing portion in the moving direction of the belt member, and comprising an upstream supporting portion supporting the first member on the upstream side and a downstream supporting portion supporting the first member on the downstream side, The second member supports the first region of the upstream support portion and the second region of the downstream support portion. The upstream support portion supports a first overlapping region of the first member that overlaps with the first region in the one direction. The downstream side support portion supports a second overlapping region of the first member that overlaps with the second region in the one direction. The fixing device further includes a heating member sandwiched between the belt member and the first member and disposed inward of the first overlapping region and the second overlapping region in the moving direction. The heating member contacts the belt member to heat the belt member.

2. The fixing device according to claim 1, wherein The first overlapping region and the second overlapping region overlap with the passing portion in the one direction.

3. A fixing device, characterized in that: include: with components; a pressing member forming a passage portion for allowing the recording medium to pass therethrough while pressing the recording medium, between the pressing member and the belt member; a first member in contact with the belt member on the inner side of the belt member and receiving a pressing force in one direction from the pressing member; a second member disposed inside the belt member and receiving a pressing force from the pressing member via the first member; as well as a supporting member, which is clamped by the first member and the second member, and supports the first member in such a manner that a region supporting the first member and a region supported by the second member overlap in the one direction; The first member is a heating member, and is the following portion: a portion arranged along the moving direction of the belt member, and supported by the support member in such a manner that the front end portion on the upstream side in the moving direction overlaps with the area of the support member supported by the second member, the heating member is arranged in the moving direction from the upstream side to the downstream side of the center of the passing portion, and the length of the portion arranged from the center to the downstream side in the moving direction is shorter than the length of the portion arranged from the center to the upstream side in the moving direction.

4. The fixing device according to claim 3, wherein The supporting member is provided from the upstream side to the downstream side relative to the center of the passing portion in the moving direction of the belt member, and includes an upstream side supporting portion supporting the first member on the upstream side and a downstream side supporting portion supporting the first member on the downstream side. The second member supports the first region of the upstream support portion and the second region of the downstream support portion. The upstream support portion supports a first overlapping region of the first member that overlaps with the first region in the one direction. The downstream-side support portion supports a second overlapping region of the first member that overlaps with the second region in the one direction.

5. The fixing device according to claim 4, wherein The first overlapping region and the second overlapping region overlap with the passing portion in the one direction.

6. A fixing device, characterized in that: include: with components; a pressing member forming a passage portion for allowing the recording medium to pass therethrough while pressing the recording medium, between the pressing member and the belt member; a first member in contact with the belt member on the inner side of the belt member and receiving a pressing force in one direction from the pressing member; a second member disposed inside the belt member and receiving a pressing force from the pressing member via the first member; as well as a supporting member, which is clamped by the first member and the second member, and supports the first member in such a manner that a region supporting the first member and a region supported by the second member overlap in the one direction; The first member is a heating member, and is the following portion: a portion arranged along the moving direction of the belt member, and supported by the support member in such a manner that the front end portion on the upstream side in the moving direction overlaps with the area of the support member supported by the second member, the heating member is arranged in the moving direction from the upstream side to the downstream side of the center of the passing portion, and the length of the portion arranged from the center to the downstream side in the moving direction is longer than the length of the portion arranged from the center to the upstream side in the moving direction.

7. The fixing device according to claim 6, wherein: The supporting member is provided from the upstream side to the downstream side relative to the center of the passing portion in the moving direction of the belt member, and includes an upstream side supporting portion supporting the first member on the upstream side and a downstream side supporting portion supporting the first member on the downstream side. The second member supports the first region of the upstream support portion and the second region of the downstream support portion. The upstream support portion supports a first overlapping region of the first member that overlaps with the first region in the one direction. The downstream-side support portion supports a second overlapping region of the first member that overlaps with the second region in the one direction.

8. The fixing device according to claim 7, wherein: The first overlapping region and the second overlapping region overlap with the passing portion in the one direction.

9. An image forming apparatus, characterized in that: include: An image forming mechanism for forming an image on a recording medium; and a fixing device that fixes the image formed on the recording medium by the image forming mechanism to the recording medium, wherein the fixing device includes the fixing device according to any one of claims 1 to 8.

Images