Fixing device, and image forming apparatus

Abstract

To prevent loosening of a winding member.SOLUTION: A fixing device comprises: a fixing roll; and a fixing barrel that rotates in a rotation direction while sandwiching, with the fixing roll, a recording medium on which an image is formed, and fixes the image to the recording medium. The fixing barrel has a barrel body that has a recess formed in its outer peripheral surface, and a sheet-like winding member that is wound around the outer peripheral surface and is attached to the barrel body with a portion on the downstream side in a rotation direction being bent inward in the radial direction of the barrel body at a corner of the recess.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 discloses a fixing device including a first roll on which an elastic layer is formed, and a second roll having a clamping portion for clamping a recording medium between the first roll and the first roll, an axially extending groove formed on the outer peripheral surface, and no elastic layer.

[0003] Patent Document 2 discloses a body member comprising a cylindrical body, a sheet member wrapped around the body, and an elastic adhesive interposed between the body and the sheet member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-31852 A [Patent Document 2] Patent Publication No. 2022-60837 Summary of the Invention [Problem to be solved by the invention]

[0005] The fixing device may include a fixing roll and a fixing copper which rotates in a rotational direction while sandwiching a recording medium on which an image has been formed between the fixing roll and the fixing copper, thereby fixing the image onto the recording medium, and the fixing copper may have a body having a recess formed on its outer peripheral surface, and a sheet-like wrapping member wrapped around the outer peripheral surface.

[0006] In this fixing device, when the entire winding member is wound only along the outer peripheral surface of the barrel body, the winding member may loosen when the fixing roll rotates in the rotational direction with the recording medium on which an image is formed being sandwiched between the fixing roll and the winding member.

[0007] The present disclosure aims to prevent the winding member from loosening, compared to when the entire winding member is wound only along the outer peripheral surface of the trunk body. [Means for solving the problem]

[0008] The first embodiment includes a fixing roll, and a fixing copper which rotates in a rotational direction while sandwiching a recording medium on which an image has been formed between the fixing roll and the fixing copper, thereby fixing the image to the recording medium. The fixing copper has a body having a recess formed on its outer peripheral surface, and a sheet-like winding member which is wrapped around the outer peripheral surface and attached to the body with the portion downstream in the rotational direction bent radially inward at the corner of the recess.

[0009] In the second aspect, in the first aspect, the portion downstream in the rotational direction has a first bent portion bent radially inward of the body at a corner of the recess, a second bent portion bent radially inward from the first bent portion, and an attachment portion attached to the body and provided on the opposite side of the first bent portion from the second bent portion.

[0010] In a third aspect, in the second aspect, the second bent portion is bent on the radially inner side with respect to the first bent portion from a direction toward the radially inner side toward a downstream side in the rotation direction.

[0011] In a fourth aspect, in the third aspect, a limiting portion is provided that limits extension of the second bent portion by sandwiching a portion on the downstream side in the rotation direction between the limiting portion and the trunk main body.

[0012] In a fifth aspect, in the third aspect, the downstream attachment portion attaches the attached portion to a radially inner bottom surface of the recess.

[0013] In a sixth aspect, in the second aspect, at least one of the first bent portion and the second bent portion is bent at an acute angle.

[0014] In a seventh embodiment, in the sixth embodiment, both the first bent portion and the second bent portion are bent at an acute angle.

[0015] In the eighth aspect, in the first aspect, a portion of the winding member upstream in the rotational direction is attached to the trunk main body, and an upstream mounting portion is provided which is movable in a pulling direction that pulls the portion upstream in the rotational direction toward the upstream side in the rotational direction.

[0016] In a ninth aspect, in the eighth aspect, the upstream mounting portion is disposed in plurality along the axial direction of the trunk main body.

[0017] A tenth aspect includes a transfer device that transfers an image to a recording medium, and the fixing device according to any one of the first to ninth aspects that fixes the image transferred to the recording medium by the transfer device onto the recording medium. Effect of the Invention

[0018] According to the configuration of the first aspect, loosening of the wrapping member is suppressed compared to when the entire wrapping member is wrapped around the trunk main body in a state where it is aligned only along the outer circumferential surface of the trunk main body.

[0019] According to the configuration of the second aspect, loosening of the winding member is suppressed compared to a case in which the portion on the downstream side in the rotation direction is bent at only one location.

[0020] According to the configuration of the third aspect, the second bent portion is bent radially inward from the first bent portion toward the upstream side in the rotation direction, making it easier to attach the attached portion to the trunk main body.

[0021] According to the configuration of the fourth aspect, loosening of the winding member is suppressed compared to a case in which the second bent portion is freely stretchable.

[0022] According to the configuration of the fifth aspect, the downstream mounting portion is less likely to interfere with other members than when the mounted portion is attached to the trunk main body radially outside of the radially inside bottom surface of the recess.

[0023] According to the configuration of the sixth aspect, loosening of the wound member is suppressed compared to a case in which both the first bent portion and the second bent portion are bent at an angle of 90 degrees or more.

[0024] According to the configuration of the seventh aspect, loosening of the wound member is suppressed compared to a case in which only one of the first bent portion and the second bent portion is bent at an acute angle.

[0025] According to the configuration of the eighth aspect, loosening of the winding member is suppressed compared to when the upstream attachment portion is fixed.

[0026] According to the configuration of the ninth aspect, loosening of the winding member is suppressed when the outer diameter of the trunk main body varies in the axial direction, compared to when the upstream attachment portion is disposed at only one location in the axial direction.

[0027] According to the configuration of the tenth aspect, image defects are suppressed compared to a case in which the entire winding member is wound in a state where it follows only the outer circumferential surface of the barrel main body. [Brief description of the drawings]

[0028] [Figure 1] 1 is a schematic diagram illustrating an image forming apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view showing a configuration around a transfer cylinder according to the embodiment. [Diagram 3] FIG. 2 is a perspective view showing a configuration around a fixing cylinder according to the embodiment. [Figure 4] FIG. 2 is a perspective view showing a gripper according to the embodiment. [Diagram 5] FIG. 2 is a partially enlarged side view of the fixing cylinder according to the embodiment. [Figure 6] FIG. 2 is a partially enlarged perspective view of a fixing cylinder according to the embodiment. [Figure 7] FIG. 4 is a side view showing the upstream attachment portion according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

[0030] <Image forming apparatus 10> The configuration of an image forming apparatus 10 according to this embodiment will be described. Fig. 1 is a schematic diagram showing the configuration of an image forming apparatus 10 according to this embodiment. Note that the arrow H shown in each figure indicates the vertical direction, which is the up-down direction of the apparatus, the arrow W indicates the horizontal direction, which is the width direction of the apparatus, and the arrow D indicates the horizontal direction, which is the depth direction of the apparatus (the front-rear direction of the apparatus). The dimensional ratios of the parts shown in each figure in the H direction, W direction, and D direction may differ from the actual dimensional ratios.

[0031] 1 is an image forming apparatus that forms a toner image (one example of an image) on a recording medium P. Specifically, the image forming apparatus 10 includes an image forming section 12, a fixing device 15, and a conveying mechanism 16. Each section of the image forming apparatus 10 (the image forming section 12, the fixing device 15, and the conveying mechanism 16) will be described below.

[0032] <Image forming unit 12> The image forming unit 12 is a component that forms a toner image on the recording medium P by an electrophotographic method. Specifically, as shown in Fig. 1, the image forming unit 12 has a toner image forming unit 20 that forms a toner image, and a transfer device 13 that transfers the toner image formed in the toner image forming unit 20 onto the recording medium P.

[0033] <Toner image forming unit 20> A plurality of toner image forming units 20 shown in Fig. 1 are provided so as to form toner images for each color. In this embodiment, toner image forming units 20 for a total of four colors, yellow (Y), magenta (M), cyan (C), and black (K), are provided. (Y), (M), (C), and (K) shown in Fig. 1 indicate components corresponding to the above-mentioned respective colors.

[0034] In addition, since the toner image forming units 20 of each color are configured in the same manner except for the toner used, in FIG. 1, the respective parts of the toner image forming unit 20(K) are denoted by reference numerals as a representative of the toner image forming units 20 of each color.

[0035] Specifically, each of the toner image forming units 20 for each color has a photoconductor 22 that rotates in one direction (for example, the counterclockwise direction in FIG. 1). Each of the toner image forming units 20 for each color also has a charger 23, an exposure device 24, and a developing device 25.

[0036] In the toner image forming unit 20 for each color, the charger 23 charges the photoconductor 22. Furthermore, the exposure device 24 exposes the photoconductor 22 charged by the charger 23 to light, thereby forming an electrostatic latent image on the photoconductor 22. Furthermore, the development device 25 develops the electrostatic latent image formed on the photoconductor 22 by the exposure device 24, thereby forming a toner image.

[0037] <Transfer device 13> 1 is a device that transfers a toner image onto a recording medium P. Specifically, the transfer device 13 performs primary transfer of the toner images on the photoconductors 22 of each color onto a transfer belt 30 serving as an intermediate transfer body, and performs secondary transfer of the superposed toner images onto the recording medium P. As shown in FIG. 1, the transfer device 13 includes the transfer belt 30, a primary transfer roll 32, and a transfer cylinder 40.

[0038] The primary transfer roll 32 is a roll that transfers the toner image of each color of the photoconductor 22 to the transfer belt 30 at a primary transfer position T1 between the photoconductor 22 and the primary transfer roll 32. In this embodiment, a primary transfer electric field is applied between the primary transfer roll 32 and the photoconductor 22, so that the toner image formed on the photoconductor 22 is transferred to the transfer belt 30 at the primary transfer position T1.

[0039] The toner image is transferred from the photoconductor 22 of each color to the outer peripheral surface of the transfer belt 30. As shown in Fig. 1, the transfer belt 30 is endless and is wound around a plurality of rolls 33 and an opposing roll 34 so as to assume an inverted triangular posture when viewed from the front (when viewed in the depth direction of the device). The transfer belt 30 rotates in the direction of arrow A when at least one of the plurality of rolls 33 is driven to rotate.

[0040] The transfer cylinder 40 has a function of transferring the toner image transferred onto the transfer belt 30 onto a recording medium P. As shown in Figures 1 and 2, this transfer cylinder 40 has a recess 41 formed on its outer circumferential surface 40A, and rotates in a rotation direction B. The recess 41 is elongated along the axial direction of the transfer cylinder 40, and has a depth along the radial direction of the transfer cylinder 40.

[0041] 1, the transfer cylinder 40 is disposed below the transfer belt 30 so as to face the transfer belt 30. Furthermore, the transfer cylinder 40 contacts the transfer belt 30 in the range of the outer peripheral surface 40A from the upstream end to the downstream end of the recess 41 in the rotation direction.

[0042] 2, a pair of sprockets 64 are provided on both axial ends of the transfer cylinder 40. The pair of sprockets 64 are arranged coaxially on the transfer cylinder 40.

[0043] The transfer cylinder 40 is rotated in a rotation direction B by a drive unit (not shown), and rotates in the rotation direction B together with the pair of sprockets 64.

[0044] In this embodiment, the transfer belt 30 and the transfer cylinder 40 convey the recording medium P in a sandwiched state at the secondary transfer position T2 (see FIG. 1). Then, the transfer cylinder 40 transfers the toner image transferred onto the transfer belt 30 to the recording medium P at the secondary transfer position T2 by applying a secondary transfer electric field between the opposing roll 34 and the transfer cylinder 40. Note that a gripper 60 and an attachment member 63 (described below) that hold the recording medium P are accommodated in a recess 41 when passing through the secondary transfer position T2, and are prevented from contacting the transfer belt 30.

[0045] <Fixing device 15> The fixing device 15 is a device that fixes the toner image transferred to the recording medium P by the transfer device 13 to the recording medium P. Specifically, as shown in Fig. 1, the fixing device 15 has a fixing cylinder 50 and a heating roll 52. The heating roll 52 is an example of a fixing roll.

[0046] In the fixing device 15, the heating roll 52 is disposed above the fixing cylinder 50. The fixing cylinder 50 has a larger diameter than the heating roll 52, and has a larger mass (i.e., moment of inertia) than the heating roll 52. The heating roll 52 has a heat source 52D such as a lamp inside (specifically, inside a main body 52A described later) and is heated by the heat source 52D.

[0047] Fixing cylinder 50 is a cylinder member that rotates in rotation direction E while sandwiching recording medium P on which a toner image has been formed between it and heating roll 52, and fixes the toner image to recording medium P. Fixing cylinder 50 has a recess 51 formed in its outer circumferential surface (specifically, outer circumferential surface 70A of cylinder main body 70 described below). Recess 51 houses gripper 60 and mounting member 63 described below. This prevents gripper 60 and mounting member 63 from coming into contact with heating roll 52 when passing through fixing position NP.

[0048] 3, a pair of sprockets 65 are provided on both axial ends of the fixing cylinder 50. The pair of sprockets 65 are arranged coaxially on the fixing cylinder 50. The fixing cylinder 50 is rotated in the rotation direction E by a drive unit (not shown), and thus rotates integrally with the pair of sprockets 65 in the rotation direction E.

[0049] In the fixing device 15, while the recording medium P is conveyed in a state in which it is sandwiched between the heating roll 52 and the fixing cylinder 50 at the fixing position NP, the heating roll 52 heats the recording medium P, and the heating roll 52 and the fixing cylinder 50 press the recording medium P, thereby fixing the toner image transferred to the recording medium P to the recording medium P. The specific configurations of the heating roll 52 and the fixing cylinder 50 will be described later.

[0050] <Transport mechanism 16> The transport mechanism 16 shown in Fig. 1 is a mechanism for transporting a recording medium P. As shown in Fig. 1 and Fig. 2, the transport mechanism 16 has a pair of chains 66 and a gripper 60. Note that Fig. 1 shows only one of the pair of chains 66, and the chain 66 and the gripper 60 are shown in a simplified form.

[0051] The pair of chains 66 are formed in a loop as shown in Fig. 1. The pair of chains 66 are arranged at an interval in the apparatus depth direction (direction D in the figure) as shown in Fig. 2. Each of the pair of chains 66 is wound around a pair of sprockets 64 provided on both axial ends of the transfer cylinder 40 and a pair of sprockets 65 (see Fig. 3) provided on both axial ends of the fixing cylinder 50. The transfer cylinder 40 is rotated in the rotation direction B (arrow B direction) and the fixing cylinder 50 is rotated in the rotation direction E, whereby the chain 66 rotates in the rotation direction C (arrow C direction).

[0052] 2, a mounting member 63 to which a gripper 60 is attached is hung between the pair of chains 66 in the device depth direction. A plurality of mounting members 63 are fixed to the pair of chains 66 at predetermined intervals along the circulating direction C of the chains 66.

[0053] As shown in Fig. 2, a plurality of grippers 60 are attached to the attachment member 63 at predetermined intervals along the depth direction of the device. The grippers 60 function as a holder that holds the leading end of the recording medium P. Specifically, as shown in Fig. 4, the gripper 60 has a claw 61 and a claw base 62. The gripper 60 is configured to hold the recording medium P by pinching the leading end of the recording medium P between the claw 61 and the claw base 62. In addition, the gripper 60 has a claw 61 pressed against the claw base 62 by a spring or the like, and the claw 61 opens and closes with respect to the claw base 62 by the action of a cam or the like.

[0054] In the transport mechanism 16, the leading end of the recording medium P sent from a storage unit (not shown) in which the recording medium P is stored is held by a gripper 60 as shown in Fig. 4. The gripper 60 holding the leading end of the recording medium P transports the recording medium P by rotating the chain 66 in the rotation direction C, and passes the secondary transfer position T2. ​​Then, at the secondary transfer position T2, the transfer cylinder 40 secondarily transfers the toner images of each color that have been primarily transferred and superimposed on the transfer belt 30 at the primary transfer position T1, onto the recording medium P at the secondary transfer position T2.

[0055] Furthermore, as the chain 66 rotates in the rotation direction C, the gripper 60 holding the leading end of the recording medium P conveys the recording medium P and passes through the fixing position NP. Then, in the fixing device 15, at the fixing position NP, the heating roll 52 sandwiches the recording medium P between the fixing cylinder 50 and the recording medium P, and the image of the recording medium P is fixed to the recording medium.

[0056] In addition, when gripper 60 passes through secondary transfer position T2, it is accommodated together with mounting member 63 in recess 41 formed on the outer peripheral surface of transfer cylinder 40, and when it passes through fixing position NP, it is accommodated together with mounting member 63 in recess 51 formed on the outer peripheral surface of fixing cylinder 50.

[0057] <Heating roll 52> As shown in FIG. 1, the heating roll 52 includes a cylindrical main body 52A, an elastic layer 52B covering the entire periphery of the main body 52A, and a release layer 52C covering the entire periphery of the elastic layer 52B.

[0058] Here, the elastic layer is a rubber layer or a resin layer, etc., with a lower elastic modulus than metal, and has a large amount of displacement with respect to force, and is a layer formed of a material with an elastic modulus (Young's modulus) of several MPa to several hundred MPa at 25° C., specifically, a layer formed of a material with an elastic modulus of 1 MPa or more and 60 MPa or less. In other words, the elastic layer functions as a deformation layer that deforms to fit the outer surface of the object when pressure is applied from the object.

[0059] <Fixing cylinder 50> As shown in Figures 1, 5 and 6, the fixing drum 50 has a drum main body 70 having a recess 51 formed on its outer peripheral surface 70A, and a sheet-like winding member 80 wrapped around the outer peripheral surface 70A of the drum main body 70.

[0060] In the following description, the rotation direction E of the fixing cylinder 50 (trunk main body 70) may be simply referred to as the "rotation direction E" or the "downstream side of the rotation direction E". The opposite side of the rotation direction E may be simply referred to as the "upstream side of the rotation direction E". The radial direction of the fixing cylinder 50 (trunk main body 70) may be simply referred to as the "radial direction". The direction from the center of the fixing cylinder 50 (trunk main body 70) toward the outside along the radial direction may be referred to as the "radial outer side", and the opposite side may be referred to as the "radial inner side". The axial direction of the fixing cylinder 50 (trunk main body 70) may be simply referred to as the "axial direction".

[0061] The trunk body 70 is formed in a substantially cylindrical shape. For example, a metal material such as stainless steel or aluminum is used for the trunk body 70. The recess 51 formed in the trunk body 70 is provided in a part of the circumferential direction of the outer circumferential surface 70A of the trunk body 70. As shown in Fig. 6, this recess 51 is elongated along the axial direction of the trunk body 70 and has a depth along the radial direction of the trunk body 70.

[0062] As described above, the winding member 80 is formed in a sheet shape. The sheet shape refers to a shape in which, when the winding member 80 is wound around the trunk main body 70, the dimension along the radial direction of the trunk main body 70 (i.e., the thickness) is at least smaller than the dimension along the axial direction of the trunk main body 70 and the dimension along the circumferential direction of the trunk main body 70, and the thickness is such that the winding member 80 can be curved along the outer peripheral surface 70A of the trunk main body 70. The sheet shape can also be called a band shape, a film shape, or a plate shape.

[0063] The winding member 80 is wound around the outer circumferential surface 70A in the range from the upstream corner 51A (see FIG. 5) to the downstream end 51B (see FIG. 5) in the rotational direction E of the recess 51 of the trunk main body 70. In other words, the winding member 80 is wound around a portion of the trunk main body 70 in the circumferential direction.

[0064] In this embodiment, when the winding member 80 is wound around the trunk main body 70, the upstream end and downstream end in the rotational direction E are not connected to form a ring (i.e., cylindrical) shape, but rather the upstream end and downstream end in the rotational direction E are separated to form a shape (approximately C-shaped when viewed in the axial direction of the trunk main body 70).

[0065] Furthermore, the winding member 80 functions as a release layer that promotes the peeling of the recording medium P, and is formed of a single layer. The winding member 80 is made of, for example, a glass cloth sheet material. The winding member 80 has a higher elastic modulus (Young's modulus) than the elastic layer 52B of the heating roll 52. The material of the winding member 80 is not limited to the above-mentioned, and various materials can be used. Unlike the heating roll 52, the fixing cylinder 50 has only the winding member 80 as a release layer, and does not have an elastic layer.

[0066] As shown in Figure 5, the winding member 80 is attached to the trunk body 70 with the downstream portion in the rotation direction E (hereinafter referred to as the downstream portion 84) bent radially inward of the trunk body 70 at the corner 51A of the recess 51.

[0067] The downstream portion 84 has a first bent portion 81 bent radially inward of the body main body 70 at the corner 51A of the recess 51, a second bent portion 82 bent radially inward from the first bent portion 81, and an attachment portion 83 provided on the opposite side of the second bent portion 82 from the first bent portion 81 and attached to the body main body 70.

[0068] Here, the bent portion is a corner formed by bending a part of the winding member 80, and is formed by two sides forming a side when viewed in the axial direction. The bent portion may have an R-shape (i.e., a rounded shape).

[0069] The first bent portion 81 is an angle formed by a side portion 85 along the outer peripheral surface 70A of the trunk main body 70 and a side portion 86 along the upstream side surface 51C of the recess 51 in the rotation direction E.

[0070] The second bent portion 82 is a corner formed by a side portion 86 along the side surface 51C of the recess 51 and a mounted portion 83 as a side portion along the radially inner bottom surface 51D of the recess 51.

[0071] The second bent portion 82 is bent from a direction toward the radially inner side toward the downstream side in the rotation direction E on the radially inner side with respect to the first bent portion 81 (specifically, on the radially inner side of the side portion 86).

[0072] Both the first bent portion 81 and the second bent portion 82 are bent at an acute angle. That is, among the angles formed by the side portion 85 and the side portion 86 constituting the first bent portion 81, the smaller angle θ1 (see FIG. 5) is an acute angle (i.e., an angle less than 90 degrees). Also, among the angles formed by the side portion 86 constituting the second bent portion 82 and the attached portion 83, the smaller angle θ2 (see FIG. 5) is an acute angle (i.e., an angle less than 90 degrees).

[0073] Furthermore, fixing cylinder 50 includes limiting portion 91 that limits extension of second bent portion 82 , and downstream side mounting portion 92 that mounts mounted portion 83 to bottom surface 51D of recess 51 .

[0074] The limiting portion 91 clamps the downstream portion 84 (specifically, the attached portion 83) between itself and the trunk main body 70, and limits the extension of the second bent portion 82. Specifically, the limiting portion 91 is made of sheet metal formed into an L-shape along the second bent portion 82 when viewed in the axial direction of the trunk main body 70. That is, the limiting portion 91 is bent from a direction toward the radially inward side toward the downstream side in the rotational direction E. As shown in FIG. 6, the limiting portion 91 is disposed along the axial direction of the trunk main body 70, and has a length in the axial direction. The dimension of the limiting portion 91 along the axial direction is equal to or greater than the dimension of the winding member 80 along the axial direction.

[0075] 5, the trunk main body 70 includes a plate body 59 that sandwiches the attached portion 83 between itself and the limiting portion 91. The dimension of the plate body 59 in the axial direction is equal to or greater than the dimension of the winding member 80 in the axial direction, and is equivalent to the dimension of the limiting portion 91 in the axial direction.

[0076] The limiting portion 91 clamps the downstream portion 84 between itself and the side surface 51C of the recess 51, and also clamps the downstream portion 84 (specifically, the attached portion 83) between itself and the radially outer surface of the plate body 59, thereby limiting the extension of the second bend portion 82.

[0077] 5 and 6, the downstream mounting part 92 is specifically configured with a plurality of screws (five in FIG. 6) arranged along the axial direction of the trunk main body 70. The downstream mounting part 92 attaches the mounting part 83 to the bottom surface 51D of the recess 51 by screwing together the limiting part 91 and the plate body 59, which sandwich the downstream section 84 (specifically, the mounting part 83).

[0078] 5 and 6, the fixing cylinder 50 further includes an upstream attachment portion 98 that attaches the portion of the winding member 80 upstream in the rotation direction (hereinafter referred to as the upstream portion 89) to the cylinder main body 70. This upstream attachment portion 98 is movable in a pulling direction that pulls the upstream portion 89 upstream in the rotation direction E. Multiple upstream attachment portions 98 (specifically, adjustment members 99, which will be described later) are arranged along the axial direction of the cylinder main body 70.

[0079] On the other hand, the trunk main body 70 has a main body mounting part 78 to which the upstream portion 89 is attached by an upstream mounting part 98. Specifically, the main body mounting part 78 is made of sheet metal formed into an L-shape when viewed in the axial direction. A plurality of main body mounting parts 78 (five in FIG. 6) are arranged at intervals along the axial direction of the trunk main body 70. A portion forming one side of the L shape of each of the plurality of main body mounting parts 78 is fixed by a fixing member 77 (e.g., a screw) to the downstream side surface 51E of the recess 51 in the rotation direction E. A portion forming the other side of the L shape of each of the plurality of main body mounting parts 78 is attached to the radially inner surface of a first mounting body 95 (described later) of the upstream mounting part 98 by an adjustment member 99 (described later).

[0080] The upstream attachment portion 98 specifically has a first attachment body 95, a second attachment body 96, an attachment member 97, and an adjustment member 99. The first attachment body 95 and the second attachment body 96 are components to which the upstream portion 89 is attached. The first attachment body 95 is disposed along the axial direction of the trunk main body 70, and has a length in the axial direction. The dimension of the first attachment body 95 in the axial direction is equal to or greater than the dimension of the winding member 80 in the axial direction. The first attachment body 95 is formed in a plate shape whose thickness direction is the radial direction of the trunk main body 70.

[0081] The second mounting body 96 is made of sheet metal formed into an L-shape when viewed in the axial direction. A plurality of second mounting bodies 96 (nine in FIG. 6 ) are arranged at intervals along the axial direction of the trunk main body 70. A portion forming one side of the L shape of each of the plurality of second mounting bodies 96 is arranged along the radially outer surface of the first mounting body 95, and this portion and this surface sandwich the upstream portion 89 therebetween.

[0082] The mounting member 97 is a member that mounts the upstream portion 89 to the first mounting body 95 and the second mounting body 96, and is configured by, for example, a screw. The mounting member 97 fixes the first mounting body 95 and the second mounting body 96 in a state in which the upstream portion 89 is sandwiched between them, thereby mounting the upstream portion 89 to the first mounting body 95 and the second mounting body 96.

[0083] The adjustment members 99 are members capable of adjusting the tension of the winding member 80, and are configured by, for example, screws. The adjustment members 99 are provided in the same number as the main body attachment parts 78. Each of the multiple adjustment members 99 passes through the first attachment body 95 and the second attachment body 96, and is screwed into each of the multiple main body attachment parts 78.

[0084] As shown in Fig. 7, the adjustment member 99 is movable in a pulling direction that pulls the upstream portion 89 upstream in the rotation direction by changing the amount of screwing into the body mounting portion 78. That is, the adjustment member 99 is capable of adjusting the tension of the winding member 80 by changing the amount of screwing into the body mounting portion 78. Note that in Fig. 7, when the amount of screwing of the adjustment member 99 into the body mounting portion 78 is changed, for example, the body mounting portion 78 before the change is shown by a two-dot chain line, and the body mounting portion 78 before the change is shown by a solid line. Also, the body mounting portion 78 shown by the solid line is the body mounting portion 78 when the amount of screwing is maximum.

[0085] Furthermore, in this embodiment, a plurality of adjustment members 99 are arranged along the axial direction of the trunk main body 70, so that the tension of the winding member 80 can be adjusted at each portion in the axial direction.

[0086] <Action according to this embodiment> In the fixing cylinder 50 according to this embodiment, the winding member 80 is attached to the cylinder body 70 in a state in which the downstream portion 84 is bent radially inward of the cylinder body 70 at the corner 51A of the recess 51.

[0087] Therefore, compared to when the entire winding member 80 is wound only along the outer peripheral surface 70A of the main body 70, even when the fixing drum 50 rotates in the rotational direction E with the recording medium P sandwiched between it and the heating roll 52 and fixes the toner image to the recording medium P, the winding member 80 is less likely to slip relative to the main body 70 due to friction with the main body 70, and loosening of the winding member 80 is suppressed.

[0088] The downstream portion 84 of the winding member 80 has a first bent portion 81 bent radially inwardly of the trunk main body 70 at the corner 51A of the recess 51, a second bent portion 82 bent radially inwardly from the first bent portion 81, and an attached portion 83 arranged on the opposite side of the first bent portion 81 from the second bent portion 82 and attached to the trunk main body 70.

[0089] Therefore, compared to when the downstream portion 84 is bent at only one location, the winding member 80 is less likely to slip relative to the trunk body 70 due to friction with the trunk body 70, and loosening of the winding member 80 is suppressed. As a result, image defects due to poor fixing caused by loosening of the winding member 80 are suppressed.

[0090] In addition, in this embodiment, the second bent portion 82 is bent radially inward from the first bent portion 81 (specifically, the radially inner side of the side portion 86) from a direction toward the radially inward toward the downstream side in the rotational direction E.

[0091] Therefore, compared to when the second bent portion 82 is bent radially inward from the first bent portion 81 toward the upstream side in the rotational direction, the attached portion 83 is exposed to the radial side (i.e., the opening side) of the recess 51, making it easier to attach the attached portion 83 to the trunk main body 70.

[0092] In this embodiment, the limiting portion 91 clamps the downstream portion 84 (specifically, the attached portion 83) between itself and the trunk main body 70, thereby limiting the extension of the second bent portion 82.

[0093] Therefore, compared to when the second bent portion 82 is freely stretchable, the state in which the winding member 80 is in contact with the trunk main body 70 is maintained, and loosening of the winding member 80 is suppressed.

[0094] In this embodiment, the downstream mounting portion 92 mounts the mounted portion 83 of the downstream portion 84 of the winding member 80 to the bottom surface 51D of the recess 51.

[0095] For this reason, the downstream mounting portion 92 is less likely to interfere with other components (such as the gripper 60 housed in the recess 51) compared to when the mounting portion 83 is attached to the trunk main body 70 radially outside the bottom surface 51D of the recess 51.

[0096] Both the first bent portion 81 and the second bent portion 82 are bent at an acute angle. Therefore, compared to a case where only one of the first bent portion 81 and the second bent portion 82 is bent at an acute angle, the winding member 80 is less likely to shift upstream in the rotation direction E, and loosening of the winding member 80 is suppressed.

[0097] The upstream attachment part 98, which attaches the upstream part 89 of the winding member 80 to the trunk main body 70, is movable in a pulling direction that pulls the upstream part 89 upstream in the rotation direction. Therefore, compared to when the upstream attachment part 98 is fixed, it is possible to pull the winding member 80 upstream in the rotation direction, and loosening of the winding member 80 is suppressed.

[0098] Furthermore, in this embodiment, multiple upstream attachment parts 98 are arranged along the axial direction of the trunk main body 70. Therefore, compared to a case in which the upstream attachment part 98 is arranged at only one location in the axial direction, loosening of the winding member 80 is suppressed when the outer diameter of the trunk main body 70 varies in the axial direction.

[0099] <Modification> In the present embodiment, the downstream portion 84 of the winding member 80 has the first bent portion 81 and the second bent portion 82, but is not limited to this. The downstream portion 84 may have, for example, only the first bent portion 81. In other words, the downstream portion 84 may be bent at only one location.

[0100] In the present embodiment, the second bent portion 82 is bent from a direction toward the radially inward side toward the downstream side in the rotation direction E at a radially inner side relative to the first bent portion 81 (specifically, at a radially inner side of the side portion 86), but is not limited thereto. The second bent portion 82 may be configured to be bent, for example, from a direction toward the radially inward side toward the upstream side in the rotation direction at a radially inner side relative to the first bent portion 81.

[0101] In the present embodiment, the limiting portion 91 restricts the extension of the second bent portion 82 by sandwiching the downstream portion 84 (specifically, the attached portion 83) between the limiting portion 91 and the trunk main body 70, but this is not limited thereto. For example, the second bent portion 82 of the downstream portion 84 may be configured to be freely extendable.

[0102] In addition, in this embodiment, the downstream mounting portion 92 mounts the mounted portion 83 of the downstream portion 84 of the winding member 80 to the bottom surface 51D of the recess 51, but this is not limited to the above. For example, the downstream mounting portion 92 may be configured to mount the mounted portion 83 to the trunk main body 70 on the radial outside of the bottom surface 51D of the recess 51.

[0103] In addition, in this embodiment, both the first bent portion 81 and the second bent portion 82 are bent at an acute angle, but this is not limited to this. For example, a configuration in which only one of the first bent portion 81 and the second bent portion 82 is bent at an acute angle may also be used. That is, in this embodiment, it is sufficient that at least one of the first bent portion 81 and the second bent portion 82 is bent at an acute angle.

[0104] By configuring at least one of the first bent portion 81 and the second bent portion 82 to be bent at an acute angle, the winding member 80 is less likely to shift upstream in the rotation direction E than when both the first bent portion 81 and the second bent portion 82 are bent at an angle of 90 degrees or more, and loosening of the winding member 80 is suppressed.

[0105] In addition, in this embodiment, the upstream attachment part 98 that attaches the upstream part 89 of the winding member 80 to the trunk main body 70 is movable in the pulling direction that pulls the upstream part 89 upstream in the rotation direction, but this is not limited to this. For example, the upstream attachment part 98 may be configured to be fixed (unmovable).

[0106] In addition, in the present embodiment, a plurality of upstream attachment parts 98 are arranged along the axial direction of the trunk main body 70, but this is not limited to the above. The upstream attachment part 98 may be arranged at only one location in the axial direction.

[0107] The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements are possible without departing from the spirit and scope of the present invention. For example, the above-described modified examples may be combined in combination as appropriate.

[0108] <Additional Notes> (((1))) A fixing roll; a fixing roller that rotates a recording medium on which an image has been formed in a rotation direction while sandwiching the recording medium between the fixing roller and the fixing roller, and fixes the image on the recording medium; Equipped with The fixed copper is A trunk main body having a recess formed on an outer peripheral surface thereof; a sheet-like winding member that is wound around the outer circumferential surface and is attached to the trunk body in a state in which a portion of the winding member that is downstream in the direction of rotation is bent toward the radial inside of the trunk body at a corner of the recess; have Fixing device.

[0109] (((2))) The portion downstream in the rotation direction is A first bent portion bent radially inwardly of the trunk main body at a corner of the recess; A second bent portion bent radially inward relative to the first bent portion; A mounting portion is provided on the opposite side of the first bent portion with respect to the second bent portion and is attached to the trunk main body; have The fixing device according to (((1))).

[0110] (((3))) The second bent portion is The first bent portion is bent from a direction toward the inside in the radial direction toward a downstream side in the rotation direction on the radially inner side with respect to the first bent portion. The fixing device according to (((2))).

[0111] (((4))) a limiting portion that limits the extension of the second bent portion by sandwiching the portion downstream in the rotation direction between the body and the limiting portion; The fixing device according to (((3))) is provided with:

[0112] (((5))) a downstream attachment portion that attaches the attached portion to a bottom surface on the radially inner side of the recess; The fixing device according to ((3))) or ((4))).

[0113] (((6))) At least one of the first bent portion and the second bent portion is bent at an acute angle. The fixing device according to any one of (((2))) to (((5))).

[0114] (((7))) Both the first bent portion and the second bent portion are bent at an acute angle. The fixing device according to (((6))).

[0115] (((8))) an upstream attachment portion that attaches an upstream portion of the winding member in a rotational direction to the trunk main body and is movable in a pulling direction that pulls the upstream portion of the winding member toward the upstream side in the rotational direction; Equipped The fixing device according to any one of ((1))) to (((7))).

[0116] (((9))) The upstream attachment portion is disposed in a plurality of portions along the axial direction of the trunk body. The fixing device according to (((8))).

[0117] (((10))) A transfer device for transferring an image onto a recording medium; A fixing device according to any one of ((1))) to (((9))) that fixes an image transferred to a recording medium by the transfer device onto the recording medium; An image forming apparatus comprising:

[0118] According to the configuration (((1))), loosening of the winding member is suppressed compared to when the entire winding member is wound in a state where it is wound only along the outer circumferential surface of the trunk main body.

[0119] According to the configuration (((2))), loosening of the winding member is suppressed compared to a case in which the portion on the downstream side in the rotational direction is bent at only one point.

[0120] According to the configuration (((3))), the second bent portion is bent radially inward from the first bent portion toward the upstream side in the direction of rotation, making it easier to attach the attached portion to the trunk main body.

[0121] According to the configuration (((4))), loosening of the winding member is suppressed compared to when the second bent portion is freely extendable.

[0122] According to the configuration (((5))), the downstream mounting portion is less likely to interfere with other components than when the mounting portion is attached to the trunk main body radially outward from the radially inner bottom surface of the recess.

[0123] According to the configuration (((6))), loosening of the winding member is suppressed compared to a case in which both the first bent portion and the second bent portion are bent at an angle of 90 degrees or more.

[0124] According to the configuration (((7))), loosening of the winding member is suppressed compared to a case in which only one of the first bent portion and the second bent portion is bent at an acute angle.

[0125] According to the configuration (((8))), loosening of the winding member is suppressed compared to when the upstream attachment portion is fixed.

[0126] According to the configuration (((9))), loosening of the winding member is suppressed when the outer diameter of the trunk main body varies in the axial direction, compared to when the upstream mounting portion is arranged at only one location in the axial direction.

[0127] According to the configuration of (((10))), image defects are suppressed compared to a case in which the entire winding member is wound only along the outer circumferential surface of the barrel body. [Explanation of symbols]

[0128] 10 Image forming device 12 Image forming section 13 Transcription device 15 Fixing device 16 Conveyor mechanism 20 Toner image forming unit 22 Photoreceptor 23 Charger 24 Exposure equipment 25 Developing device 30 Transfer belt 32 Primary transfer roll 33 Rolls 34 Opposing Roll 40 Transfer cylinder 40A outer surface 41 Recess 50 Fixed torso 51 Recess 51A Corner 51B Downstream end 51C side 51D Bottom 51E Side 52 Heating roll 52A Main Unit 52B Elastic layer 52C Release layer 52D heating source 59 Plate 60 Gripper 61 Nails 62 Nail stand 63 Mounting material 64 Sprocket 65 sprocket 66 Chain 70 Body 70A outer surface 77 Fixing member 78 Main body mounting part 80 Winding member 81 First bending part 82 Second bending part 83 Mounting part 84 Downstream part 85 Edge 86 Side 89 Upstream part 91 Restrictions 92 Downstream mounting part 95 First mounting body 96 Second mounting body 97 Mounting material 98 Upstream mounting part 99 Adjustment parts P Recording medium

Claims

1. A fixing roll; a fixing roller that rotates a recording medium on which an image has been formed in a rotation direction while sandwiching the recording medium between the fixing roller and the fixing roller, and fixes the image on the recording medium; Equipped with The fixed copper is A trunk main body having a recess formed on an outer peripheral surface thereof; a sheet-like winding member that is wound around the outer circumferential surface and is attached to the trunk body in a state in which a portion of the winding member that is downstream in the direction of rotation is bent toward the radial inside of the trunk body at a corner of the recess; have Fixing device.

2. The portion downstream in the rotation direction is A first bent portion bent radially inwardly of the trunk main body at a corner of the recess; A second bent portion bent radially inward relative to the first bent portion; A mounting portion is provided on the opposite side of the first bent portion with respect to the second bent portion and is attached to the trunk main body; have The fixing device according to claim 1 .

3. The second bent portion is The first bent portion is bent from a direction toward the inside in the radial direction toward a downstream side in the rotation direction on the radially inner side with respect to the first bent portion. The fixing device according to claim 2 .

4. a limiting portion that limits the extension of the second bent portion by sandwiching the portion downstream in the rotation direction between the body and the limiting portion; The fixing device according to claim 3 .

5. a downstream attachment portion that attaches the attached portion to a bottom surface on the radially inner side of the recess; The fixing device according to claim 3 .

6. At least one of the first bent portion and the second bent portion is bent at an acute angle. The fixing device according to claim 2 .

7. Both the first bent portion and the second bent portion are bent at an acute angle. The fixing device according to claim 6 .

8. an upstream attachment portion that attaches an upstream portion of the winding member in a rotational direction to the trunk main body and is movable in a pulling direction that pulls the upstream portion of the winding member toward the upstream side in the rotational direction; Equipped The fixing device according to claim 1 .

9. The upstream attachment portion is disposed in a plurality of portions along the axial direction of the trunk body. The fixing device according to claim 8 .

10. A transfer device for transferring an image onto a recording medium; a fixing device according to any one of claims 1 to 9, which fixes the image transferred to a recording medium by the transfer device onto the recording medium; An image forming apparatus comprising:

Images