Fixing device

Abstract

To provide a fixing device in which the behavior of all bristles of a charge eliminating brush is stable.SOLUTION: A fixing device 1 comprises: a heater 10, a belt 40, and a charge eliminating brush 5. The belt 40 is endless and rotates around the heater 10. The charge eliminating brush 5 removes static charge from the belt 40. The charge eliminating brush 5 includes: a plurality of bristles 51 having a distal end 51A in contact with an outer peripheral surface 40B of the belt 40; and a holding frame 52 that holds a proximal end 51B of the plurality of bristles 51. The holding frame 52 holds the plurality of bristles 51 such that all of the plurality of bristles 51 contacting the belt 40 are oriented so that a direction from the proximal end 51B toward the distal end 51A is directed to a direction along a rotation direction of the belt 40.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a fixing device that fixes a toner image on a sheet. [Background technology]

[0002] A fixing device that fixes a toner image on a sheet is known (see Patent Document 1). This fixing device is provided with a static elimination brush having multiple bristles. The static elimination brush comes into contact with the outer surface of the belt to eliminate static electricity from the belt. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-171185 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional static eliminating brush of the fixing device has a problem in that the tips of the bristles do not face in a fixed direction, and the behavior of the bristles is unstable.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a fixing device in which the behavior of all the bristles of the charge eliminating brush is stable. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, a fixing device according to the present invention includes a heater, a belt, and a discharging brush. The heater extends in a first direction. The belt rotates around the heater. The belt is endless. The anti-static brush neutralizes the belt. The anti-static brush has a plurality of bristles whose tips contact the outer peripheral surface of the belt and a holding frame that holds the base ends of the bristles. The holding frame holds the bristles so that the direction from the base end to the tip end of all of the bristles in contact with the belt is aligned with the direction of rotation of the belt.

[0007] The holding frame holds the bristles so that the direction from the base end to the tip of all the bristles that come into contact with the belt is aligned with the direction of rotation of the belt, thereby stabilizing the behavior of all the bristles of the anti-static brush.

[0008] The apparatus may further include a pressure rotating body that contacts the belt and transports the sheet together with the belt. The outer peripheral surface of the belt may have a first contact area that contacts the sheet when transporting the sheet and a first non-contact area that does not contact the sheet when transporting the sheet. The bristles may be configured to contact the first non-contact area but not to contact the first contact area.

[0009] Since the bristles of the anti-static brush contact the first non-contact area but do not contact the first contact area, even if foreign matter adheres to the bristles, the foreign matter can be prevented from adhering to the sheet.

[0010] The sheet conveying device may further include a pressure rotating body that contacts the belt and conveys the sheet together with the belt. The outer peripheral surface of the belt may have a second contact area that contacts the pressure rotating body and a second non-contact area that does not contact the pressure rotating body. The bristles may be configured to contact the second non-contact area but not contact the second contact area.

[0011] Since the bristles of the anti-static brush contact the second non-contact area but do not contact the second contact area, even if foreign matter adheres to the bristles, the foreign matter can be prevented from adhering to the pressure rotating body.

[0012] The belt may have a base layer and a surface layer that covers the base layer and contacts the sheet, and the bristles may be configured to contact the base layer but not the surface layer.

[0013] Since the plurality of bristles come into contact with the base layer, the base layer can be stably neutralized. Furthermore, even if foreign matter adheres to the plurality of bristles, the foreign matter can be prevented from adhering to the surface layer.

[0014] The belt may have a base layer, a surface layer covering the base layer and in contact with the sheet, and an intermediate layer located between the surface layers. The bristles may be configured to be in contact with the base layer but not with the surface layer or the intermediate layer.

[0015] Since multiple bristles come into contact with the base layer, static electricity can be removed stably. Furthermore, even if foreign matter adheres to multiple bristles, the foreign matter can be prevented from adhering to the surface layer.

[0016] The cleaning device may further include a side guide that contacts the end face of the belt in the first direction and guides the end face of the belt in the first direction. The side guide may have an end face guide that contacts the end face and restricts movement of the belt in the first direction, and a restricting rib that protrudes from the end face guide in the first direction and is capable of contacting the plurality of bristles.

[0017] When multiple bristles move in the first direction, they come into contact with the restricting rib of the side guide, thereby preventing further movement.

[0018] The belt may further include an inner circumferential guide that contacts an end of the inner circumferential surface of the belt in the first direction to guide the rotation of the belt. The belt may have a third contact region that contacts the inner circumferential guide and a third non-contact region that does not contact the inner circumferential guide. The bristles may be configured to contact the third contact region but not the third non-contact region.

[0019] Since multiple bristles come into contact with the third contact area, it is possible to prevent the belt from becoming unstable.

[0020] The sheet conveying device may further include a heating rotator having a heater and a belt, and a pressure rotator in contact with the belt and transporting the sheet together with the belt. The sheet conveying device may further include a movement mechanism for moving the heating rotator relative to the pressure rotator, the movement mechanism moving the heating rotator between a first position where a pressing force at a nip portion between the heating rotator and the pressure rotator is a first pressing force and a second position where the pressing force at the nip portion is a second pressing force smaller than the first pressing force. All of the bristles in contact with the belt may be configured such that the direction from the base end to the tip end is aligned with the rotation direction of the belt at both the first and second positions.

[0021] The tufts of bristles may be longer in the direction of rotation of the belt than in the first direction.

[0022] The belt may have one end and the other end in the first direction, and the anti-static brush may be disposed closer to the one end of the belt than the other end. All of the bristles may be inclined so that the direction from the base end to the tip end faces from one end of the belt to the other end.

[0023] Furthermore, all of the bristles may be configured so that the direction in which they extend from the holding frame at their base ends faces downstream in the belt rotation direction with respect to a first line connecting the base ends and the center of rotation of the belt.

[0024] Furthermore, for all the multiple bristles, the straight line along which the bristles extend from the holding frame may be closer to a second straight line that passes through the base end and touches the belt in a region downstream of the first straight line in the direction of rotation of the belt than to a first straight line that connects the base end and the center of rotation of the belt. [Effects of the Invention]

[0025] According to the present invention, it is possible to provide a fixing device in which the behavior of all the bristles of the charge eliminating brush is stable. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 2 is a cross-sectional view showing the fixing device according to the embodiment. [Figure 2] 3 is a view of the static elimination brush and side guide of the first embodiment as viewed from a first direction. FIG. [Figure 3] 3 is a diagram showing a state in which the heating unit has been moved from the state in FIG. 2 to a second position. [Figure 4] FIG. [Figure 5] FIG. 2 is a diagram showing a first contact area, a first non-contact area, a second contact area, and a second non-contact area of ​​a belt. [Figure 6] 4A is a cross-sectional view showing a state in which the static elimination brush in the first embodiment is in contact with the surface layer of the belt, and FIGS. 4B and 4C are views showing a state in which the static elimination brush is in contact with the base layer. [Figure 7] 1A is a perspective view of a side guide of the first embodiment, and FIG. 1B is a cross-sectional view showing the positional relationship between the side guide, a belt, and a static elimination brush. [Figure 8] FIG. 2 is a cutaway perspective view of the fixing device at the position of the charge removal brush. [Figure 9] FIG. 10 is a perspective view of a side guide according to a second embodiment. [Figure 10] 10 is a view of the static elimination brush and side guide of the second embodiment as viewed from a first direction. FIG. [Figure 11] FIG. 10 is a cutaway perspective view of a fixing device according to a second embodiment, taken at the position of a discharging brush. [Figure 12] 10A and 10B are diagrams showing the arrangement of the anti-static brush in other forms, in which (a) the tip faces inward and (b) the tip faces outward. [Figure 13] 10A and 10B are diagrams showing the arrangement of the static elimination brush in another embodiment, in which the static elimination brush is arranged at an angle as a whole; DETAILED DESCRIPTION OF THE INVENTION

[0027] Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1, the fixing device 1 is a device that fixes a toner image on a sheet S. The fixing device 1 is installed in an image forming apparatus such as a printer. The fixing device 1 includes a heating unit 2 as an example of a heating rotor having a belt 40, a pressure roller 3 as an example of a pressure rotor, a frame 4, a discharging brush 5, and a movement mechanism 6.

[0028] The pressure roller 3 is rotatable about a third axis X3. The pressure roller 3 conveys the sheet S by nipping it between itself and the heating unit 2 at the nip portion NP. The pressure roller 3 has a shaft 3A and an elastic layer 3B. The shaft 3A extends in the axial direction. The elastic layer 3B covers the outer peripheral surface of the shaft 3A.

[0029] The frame 4 supports the heating unit 2 and the pressure roller 3. The frame 4 has a first frame 41 that supports the heating unit 2 and a second frame 42 that supports the pressure roller 3.

[0030] The movement mechanism 6 is a mechanism for moving the heating unit 2 relative to the pressure roller 3. The moving mechanism 6 is a mechanism that moves at least one of the first frame 41 and the second frame 42. The moving mechanism 6 moves the heating unit 2 between a first position shown by a solid line in Fig. 1 and a second position shown by a virtual line (in Fig. 1, only the belt 40 located at the second position is shown by a virtual line, and other parts are omitted). When the heating unit 2 is located at the first position, the pressing force at the nip portion NP between the heating unit 2 and the pressure roller 3 becomes a first pressing force. When the heating unit 2 is located at the second position, the pressing force at the nip portion NP becomes a second pressing force that is smaller than the first pressing force.

[0031] In the following description, the axial direction of the pressure roller 3 is referred to as the "first direction." The direction in which the heating unit 2 and the pressure roller 3 are aligned and which is perpendicular to the first direction is referred to as the "second direction." The conveying direction of the sheet S at the nip portion NP is referred to as the "third direction." In this embodiment, the third direction is a direction perpendicular to the first and second directions. In the drawings, arrows indicating directions will point to one side.

[0032] 2, the static elimination brush 5 is a member that eliminates static electricity from the belt 40. Specifically, the static elimination brush 5 is attached to the first frame 41 of the frame 4. The static elimination brush 5 is grounded by an earth member (not shown).

[0033] The anti-static brush 5 has a plurality of bristles 51 and a holding frame 52 .

[0034] The bristles 51 are made of conductive fibers. In this embodiment, the bristles 51 have a plurality of fiber bundles of several tens to several hundreds of fibers, and the fiber bundles are aligned in the rotation direction of the belt 40. That is, in this embodiment, the bundles of the bristles 51 are longer in the rotation direction of the belt 40 than in the first direction (see also FIG. 6). The bristles 51 have a tip end 51A and a base end 51B.

[0035] Base end 51B refers to the base of the portion of bristles 51 that is not fixed to holding frame 52. In other words, the portion of bristles 51 that can bend freely is from base end 51B to tip end 51A.

[0036] Tips 51A of the bristles 51 contact the outer peripheral surface 40B of the belt 40. The direction from base end 51B to tip end 51A of all of the bristles 51 contacting the belt 40 is oriented in the direction of rotation of the belt.

[0037] Here, a line passing through the rotation center X1 of the belt 40 and perpendicular to the conveying direction of the sheet S is defined as a center line C. The bristles 51 are arranged only upstream of the center line C in the conveying direction of the sheet S in the third direction. The bristles 51 extend from the base end 51B along the second direction. The rotation center X1 of the belt 40 is determined by the shape of the member that guides the belt 40. In this embodiment, the rotation center X1 of the belt 40 is the center of the inner guide 61 of the side guide 60.

[0038] The direction in which all of the bristles 51 extend from the holding frame 52 at the base end 51B (see the straight line L2 in Figure 2) faces downstream in the rotation direction of the belt 40 with respect to the first straight line L1 connecting the base end 51B and the rotation center X1 of the belt 40.

[0039] Furthermore, for all the multiple bristles 51, the straight line L2 along the direction in which the bristles extend from the holding frame 52 is closer to the first straight line L1 connecting the base end 51B and the rotation center X1 of the belt 40 than the second straight line L3 that passes through the base end 51B and touches the belt 40 upstream of the center line C in the conveying direction of the sheet S.

[0040] The holding frame 52 holds the plurality of bristles 51. More specifically, the holding frame 52 holds the plurality of bristles 51 so that the direction from the base end 51B to the tip end 51A of all of the plurality of bristles 51 in contact with the belt 40 is aligned with the rotation direction of the belt 40.

[0041] 3, even when the heating unit 2 is located at the second position, the direction from the base end 51B to the tip end 51A of the multiple bristles 51 is oriented in the direction along the rotation direction of the belt 40. In other words, whether the heating unit 2 is located at the first position or the second position, the direction from the base end 51B to the tip end 51A of the multiple bristles 51 is oriented in the direction along the rotation direction of the belt 40.

[0042] As shown in FIG. 4, the heating unit 2 includes a heater 10, a holder 20, a stay 30, a belt 40, a side holder 50, and a side guide 60.

[0043] The heater 10 heats the sheet S via the belt 40. The heater 10 has a plate shape and extends in a first direction. The heater 10 is in sliding contact with an inner circumferential surface 40A of the belt 40. The heater 10 is a so-called ceramic heater.

[0044] As shown in FIGS. 1 and 4, the holder 20 supports the heater 10 and also functions to guide the belt 40. Specifically, the holder 20 has a recess 21 and a guide rib 22. The recess 21 is a recessed portion that accommodates the heater 10. A plurality of the guide ribs 22 are arranged in a line in the first direction and guide the belt 40. The holder 20 is made of, for example, resin.

[0045] The stay 30 is a U-shaped member that supports the holder 20. The stay 30 contacts the holder 20 from the side opposite the heater 10. Specifically, the stay 30 has a first wall 31, a second wall 32, and a third wall 33. The first wall 31 is a wall that is perpendicular to the third direction. One end of the first wall 31 in the second direction contacts the holder 20. The second wall 32 is a wall that extends parallel to the first wall 31 and is located on one side of the first wall 31 in the third direction. One end of the second wall 32 in the second direction contacts the holder 20. The third wall 33 connects the other end of the first wall 31 in the second direction to the other end of the second wall 32 in the second direction. The stay 30 is conductive. The stay 30 is made of, for example, metal.

[0046] The belt 40 is endless. The belt 40 is made of metal, resin, or the like. The belt 40 rotates around the heater 10 while being guided by the holder 20. The belt 40 forms a nip portion NP with the pressure roller 3. The belt 40 rotates in contact with the pressure roller 3 and transports the sheet S together with the pressure roller 3. The belt 40 has an inner peripheral surface 40A and an outer peripheral surface 40B.

[0047] The inner circumferential surface 40A comes into contact with the heater 10. Grease GR, which is an example of a lubricant, is disposed on the inner circumferential surface 40A of the belt 40. The type of grease GR is not particularly limited, but in this embodiment, grease GR containing fluorine oil as a base oil, a thickener, and additives is used.

[0048] The outer peripheral surface 40B comes into contact with the pressure roller 3 or the sheet S to be heated. 5, the outer peripheral surface 40B of the belt 40 has a first contact region R1 that comes into contact with the sheet S when the sheet S is being transported, and a first non-contact region R2 that does not come into contact with the sheet S when the sheet S is being transported. The bristles 51 of the static elimination brush 5 come into contact with the first non-contact region R2, but do not come into contact with the first contact region R1.

[0049] The outer peripheral surface 40B of the belt 40 has a second contact region R3 that contacts the pressure roller 3 and a second non-contact region R4 that does not contact the pressure roller 3. The bristles 51 of the static elimination brush 5 contact the second non-contact region R4 but do not contact the second contact region R3.

[0050] As shown in Fig. 6(a), the belt 40 has a base layer 40K and a surface layer 40S. The surface layer 40S is a layer that covers the base layer 40K. The surface layer 40S is a layer that comes into contact with the sheet S. In this embodiment, the bristles 51 of the static elimination brush 5 come into contact with the surface layer 40S, but do not come into contact with the base layer 40K.

[0051] As shown in FIG. 4, the side holders 50 are attached to both ends of the stay 30 in the first direction. The side holders 50 are attached to the ends of the stay 30. The two side holders 50 have the same shape. The side holders 50 have contact surfaces 50A that come into contact with the side guides 60. The side holders 50 are made of, for example, resin.

[0052] The side guides 60 are provided at both ends of the belt 40 in the first direction. The side guides 60 are attached to the stay 30 so as to be able to swing. The two side guides 60 are arranged so as to come into contact with the ends of the belt 40 in the first direction, and guide the ends of the belt 40 in the first direction. In this embodiment, the two side guides 60 have the same shape.

[0053] The side guide 60 includes an inner circumferential guide 61 , an end face guide 62 , a restricting rib 63 , and a protrusion 65 .

[0054] As shown in FIGS. 7(a) and 7(b), the inner circumferential guide 61 comes into contact with an end portion of the inner circumferential surface 40A of the belt 40 in the first direction, and guides the end portion of the inner circumferential surface 40A of the belt 40 in the first direction. The inner circumferential guide 61 extends in an arc shape. The inner circumferential guide 61 extends so as to guide a range of 50 to 80% of the end portion of the belt 40 in the circumferential direction. Grease GR is disposed between the inner circumferential guide 61 and the inner circumferential surface 40A of the belt 40.

[0055] The belt 40 has a third contact region R5 that contacts the inner circumferential guide 61 and a third non-contact region R6 that does not contact the inner circumferential guide 61. The bristles 51 of the static elimination brush 5 contact the third contact region R5 but do not contact the third non-contact region R6.

[0056] The end face guide 62 is capable of coming into contact with the first-direction end face 40T of the belt 40. The end face guide 62 guides the first-direction end face 40T of the belt 40 and restricts movement of the belt 40 in the first direction.

[0057] The end face guide 62 extends from the inner circumferential guide 61 in a direction perpendicular to the first direction. The end face guide 62 extends radially outward in a flange-like shape from the center of the arc of the inner circumferential guide 61. The end face guide 62 is not always in contact with the end face 40T of the belt 40, and may or may not come into contact depending on the behavior of the belt 40.

[0058] The restricting rib 63 is a rib that protrudes in the first direction from the end face guide 62. The restricting rib 63 extends in the third direction so as to cover only the upper part of the belt 40. The restricting rib 63 can come into contact with the multiple bristles 51 of the static elimination brush 5. Specifically, the restricting rib 63 can come into contact with the multiple bristles 51 of the static elimination brush 5 when they move in the first direction.

[0059] 4, the protruding portion 65 is a portion that protrudes in a first direction from the end face guide 62. The protruding portion 65 protrudes from the end face guide 62 on the side opposite to the inner circumferential guide 61. The arcuate surface of the protruding portion 65 comes into contact with the contact surface 50A of the side holder 50, allowing the side guide 60 to swing relative to the holder 20.

[0060] In the fixing device 1 described above, the operation of the charge removal brush 5 will be described with reference to FIG.

[0061] 8, the bristles 51 of the static elimination brush 5 extend from the base end 51B toward the belt 40, and the tips 51A are in contact with the outer peripheral surface 40B of the belt 40. The tips 51A of the bristles 51 are in contact with the belt 40, so that the bristles 51 are bent in the direction of rotation. In this way, the direction from the base end 51B to the tips 51A of all the bristles 51 in contact with the belt 40 is oriented in the direction of rotation of the belt 40. As the belt 40 moves in the first direction, the tips 51A of the bristles 51 may move to one side or the other in the first direction. If the bristles 51 move to one side in the first direction, the bristles 51 may come into contact with the restricting rib 63 of the side guide 60. If the bristles 51 come into contact with the restricting rib 63, their movement is restricted by the restricting rib 63, and the bristles 51 do not move any further to one side in the first direction.

[0062] As described above, the following effects can be obtained in this embodiment. According to the fixing device 1 of the first embodiment, the holding frame 52 of the static elimination brush 5 holds the bristles 51 so that the direction from the base end 51B to the tip end 51A of all of the bristles 51 in contact with the belt 40 is aligned with the rotation direction of the belt 40. This stabilizes the behavior of all of the bristles 51 of the static elimination brush 5.

[0063] Furthermore, since the multiple bristles 51 of the anti-static brush 5 contact the first non-contact area R2 but do not contact the first contact area R1, even if foreign matter adheres to the multiple bristles 51, the foreign matter can be prevented from adhering to the sheet S.

[0064] Furthermore, since the multiple bristles 51 of the anti-static brush 5 contact the second non-contact area R4 but do not contact the second contact area R3, even if foreign matter adheres to the multiple bristles 51, the foreign matter can be prevented from adhering to the pressure roller 3.

[0065] Furthermore, when the bristles 51 move in the first direction, they come into contact with the restricting rib 63 of the side guide 60, thereby preventing further movement.

[0066] Furthermore, since multiple bristles 51 contact the third contact area R5, even if the static elimination brush 5 contacts the belt 40, the static elimination brush 5 does not affect the behavior of the belt 40, and the behavior of the belt 40 can be prevented from becoming unstable.

[0067] Next, a second embodiment will be described. The second embodiment differs from the first embodiment in the shape of the side guide. The same reference numerals are used for the parts common to the first embodiment, and the description thereof will be omitted.

[0068] As shown in Figures 9 and 10, the side guide 60A in the second embodiment has a restricting rib 63B. While the restricting rib 63 in the first embodiment extends in the third direction so as to cover only the upper part of the belt 40 (see Figures 2 and 3), the restricting rib 63B extends so as to cover not only the upper part of the belt 40 but also the side parts thereof. Specifically, the restricting rib 63A extends in an arc shape. The restricting rib 63A extends in the same range as the inner circumferential guide 61, i.e., in a range of 50 to 80% in the circumferential direction.

[0069] 11, even with the side guide 60A of the second embodiment, if the bristles 51 move to one side in the first direction, they will come into contact with the restricting rib 63 of the side guide 60. When the bristles 51 come into contact with the restricting rib 63, further movement of the bristles 51 is restricted.

[0070] The present invention is not limited to the above-described embodiment, but can be used in various forms as exemplified below.

[0071] In the above-described embodiment, the belt 40 has a surface layer 40S and a base layer 40K, and the bristles 51 of the anti-static brush 5 are in contact with the surface layer 40S (see FIG. 6(a)). However, as shown in FIG. 6(b), the bristles 51 may be in contact with the base layer 40K but not with the surface layer 40S. In this configuration, the bristles 51 come into contact with the base layer 40K, and therefore, it is possible to stably neutralize the base layer 40K of the belt 40. Even if foreign matter adheres to the bristles 51, it is possible to prevent the foreign matter from adhering to the surface layer 40S.

[0072] In the above-described embodiment, the belt 40 is composed of the surface layer 40S and the base layer 40K. The belt 140 may further include an intermediate layer 40M located between the surface layer 40S and the base layer 40K. In this case, the bristles 51 of the static elimination brush 5 are in contact with the base layer 40K and are not in contact with the surface layer 40S and the intermediate layer 40M.

[0073] In the above-described embodiment, the bundle of multiple bristles 51 was configured to be longer in the rotation direction of the belt 40 than in the first direction, but the bundle of multiple bristles 51 may also be configured to be longer in the first direction than in the rotation direction of the belt 40 (not shown).

[0074] In the above-described embodiment, the static elimination brush 5 extends along the second direction when viewed from the third direction, but as shown in Fig. 12(a), the entire static elimination brush 5 may be tilted so that the tip 51A of the static elimination brush 5 faces one side in the first direction when viewed from the third direction. In other words, when the belt 40 has one end and the other end in the first direction and the static elimination brush 5 is positioned closer to one end of the belt 40 than the other end, all of the multiple bristles 51 of the static elimination brush 5 are tilted so that the direction from the base end 51B to the tip 51A faces from one end of the belt 40 to the other end.

[0075] Furthermore, as shown in FIG. 12(b), the entire static elimination brush 5 may be tilted so that the tip 51A of the static elimination brush 5 faces the other side in the first direction when viewed from the third direction.

[0076] In the above-described embodiment, for all the multiple bristles 51, the straight line L2 along the direction in which the bristles extend from the holding frame 52 is closer to the first straight line L1 connecting the base end 51B and the center of rotation X1 of the belt 40 than the second straight line L3 that passes through the base end 51B and touches the belt 40 upstream of the center line C in the conveying direction of the sheet S, but this is not limited to this. For example, in the anti-static brush 105 of Figure 13, for all of the multiple bristles 151, the straight line L2 along the direction in which the bristles extend from the holding frame 152 is closer to the second straight line L3 that passes through the base end 151B and is tangent to the belt 40 in the area downstream of the first straight line L1 in the rotation direction of the belt 40 than to the first straight line L1 that connects the base end 151B and the rotation center X1 of the belt 40. Even with this configuration, the holding frame 152 of the static elimination brush 105 holds the multiple bristles 151 so that all of the multiple bristles 151 in contact with the belt 40 are oriented such that the direction from the base end 151B to the tip end 151A is aligned with the rotation direction of the belt 40. This stabilizes the behavior of all of the bristles 151 of the static elimination brush 105.

[0077] In the above-described embodiment, the anti-static brush 5 is made of conductive fibers, but the anti-static brush 5 may be made of other materials, such as metals such as stainless steel, as long as the material is conductive.

[0078] The elements described in the above-described embodiment and modifications may be implemented in any combination. [Explanation of symbols]

[0079] 1 Fixing device 2 heating units 3 Pressure roller 5 Anti-static brush 10 Heater 40 Belt 40A inner surface 40B Outer surface 51 Multiple Hairs 51A Tip 51B Proximal end 52 Retaining Frame

Claims

1. a heater extending in a first direction; an endless belt that rotates around the heater; a static elimination brush for eliminating static electricity from the belt, the static elimination brush having a plurality of bristles whose tips contact the outer peripheral surface of the belt and a holding frame that holds the base ends of the plurality of bristles; A fixing device characterized in that the holding frame holds the plurality of bristles so that all of the plurality of bristles that contact the belt are oriented in a direction from the base end to the tip end along the rotation direction of the belt.

2. The sheet conveying device further includes a pressure rotating body that contacts the belt and conveys the sheet together with the belt, the outer peripheral surface of the belt has a first contact area that comes into contact with the sheet when conveying the sheet, and a first non-contact area that does not come into contact with the sheet when conveying the sheet, The fixing device according to claim 1 , wherein the plurality of bristles contact the first non-contact area and do not contact the first contact area.

3. The sheet conveying device further includes a pressure rotating body that contacts the belt and conveys the sheet together with the belt, the outer peripheral surface of the belt has a second contact region that contacts the pressure rotating body and a second non-contact region that does not contact the pressure rotating body, The fixing device according to claim 1 , wherein the plurality of bristles contact the second non-contact area and do not contact the second contact area.

4. the belt has a base layer and a surface layer that covers the base layer and comes into contact with a sheet, 2. The fixing device according to claim 1, wherein the plurality of bristles contact the base layer but do not contact the surface layer.

5. the belt has a base layer, a surface layer covering the base layer and contacting a sheet, and an intermediate layer positioned between the surface layers, 2. The fixing device according to claim 1, wherein the bristles contact the base layer and do not contact the surface layer or the intermediate layer.

6. a side guide that contacts an end surface of the belt in the first direction and guides the end surface of the belt in the first direction; The side guide is an end face guide that contacts the end face and restricts movement of the belt in the first direction; The fixing device according to claim 1 , further comprising: a restriction rib that protrudes from the end surface guide in the first direction and is capable of coming into contact with the plurality of bristles.

7. an inner circumferential guide that contacts an end of the inner circumferential surface of the belt in the first direction to guide the rotation of the belt; the belt has a third contact region that contacts the inner circumferential guide and a third non-contact region that does not contact the inner circumferential guide, The fixing device according to claim 1 , wherein the plurality of bristles contact the third contact area and do not contact the third non-contact area.

8. a heating rotor including the heater and the belt; The sheet conveying device further includes a pressure rotating body that contacts the belt and conveys the sheet together with the belt, a moving mechanism that moves the heating rotator relative to the pressure rotating body, the moving mechanism moving the heating rotator between a first position where a pressing force at a nip portion between the heating rotator and the pressure rotating body is a first pressing force and a second position where the pressing force at the nip portion is a second pressing force that is smaller than the first pressing force; 2. The fixing device according to claim 1, wherein all of the bristles contacting the belt are oriented in a direction from the base end to the tip end along the direction of rotation of the belt, in both the first position and the second position.

9. The fixing device according to claim 1 , wherein the plurality of bristle bundles are longer in the rotation direction of the belt than in the first direction.

10. The fixing device according to claim 1 , wherein the plurality of bristle bundles are longer in the first direction than in the rotation direction of the belt.

11. The belt has one end and the other end in the first direction, the anti-static brush is disposed at a position closer to the one end of the belt than to the other end, 2. The fixing device according to claim 1, wherein all of the bristles are inclined such that the direction from the base end to the tip end is directed from the one end to the other end of the belt.

12. 2. The fixing device according to claim 1, wherein the direction in which all of the bristles extend from the holding frame at the base end faces downstream in the direction of rotation of the belt with respect to a first straight line connecting the base end and the center of rotation of the belt.

13. The fixing device described in claim 1, characterized in that for all of the multiple bristles, the straight line along the direction in which the bristles extend from the holding frame is closer to a second straight line that passes through the base end and is tangent to the belt in a region downstream of the first straight line in the direction of rotation of the belt, than to a first straight line that connects the base end and the center of rotation of the belt.

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