JP2023154922A - Fixing device and image forming apparatus - Google Patents

Abstract

To provide a fixing device and an image forming apparatus that can provide heat resistance to a part to be regulated and prevent wear of the part to be regulated and/or a regulation part.SOLUTION: A fixing belt 31 is provided with a heat resistant member 42a on its inner peripheral surface 311 and further provided with a slidable member 42b on the heat resistant member 42a, a regulation part 43 is composed of a step part 43a, a part to be regulated 42 is composed of the heat resistant member 42a and the slidable member 42b, and at least part of a side face 42b1 of the slidable member 42b faces the step part 43a. Alternatively, the step part 44 is provided with the slidable member 43b, the fixing belt 31 is provided with the heat resistant member 42a on the inner peripheral surface 311, the regulation part 43 is composed of the slidable member 43b, the part to be regulated 42 is composed of the heat resistant member 42a, and a side face 42a1 of the heat resistant member 42a faces a side face 43b1 of the slidable member 43b.SELECTED DRAWING: Figure 6A

Description

The present invention relates to a fixing device and an image forming apparatus such as a copying machine, a multifunction device, a printer, and a facsimile machine.

A fixing device for fixing an unfixed toner image onto a sheet such as a recording paper includes a holding member fixed to a main body of the fixing device, and a fixing belt rotatably provided on the outer peripheral surface of the holding member around a rotation axis. There is something.

In such a fixing device, movement (shifting) of the fixing belt in the rotational axis direction occurs due to various factors. In this case, the end portion of the fixing belt and/or the wall surface of the holding member facing the fixing belt may be damaged or damaged.

In order to eliminate such inconveniences, conventionally, a regulating portion is provided on the outer circumferential surface of the holding member facing the fixing belt, and a regulating portion is provided on the inner circumferential surface of the fixing belt opposite to the holding member. A fixing device has been proposed in which the movement of the fixing belt in the rotational axis direction is restricted by having a portion to be restricted and the restriction portion coming into contact with the restriction portion (see, for example, Patent Document 1).

Specifically, in Patent Document 1, a meandering prevention member made of a material with excellent heat resistance, such as silicone rubber or fluororubber, is used as the regulated portion.

Japanese Patent Application Publication No. 2007-108525

However, although heat resistance can be imparted to the regulated part used in the fixing device described in Patent Document 1, sliding property (abrasion resistance) is not taken into account, and the regulated part is not regulated. If the regulated portion and/or the regulated portion come into contact with the regulated portion, the regulated portion and/or the regulated portion are likely to wear out.

Therefore, it is an object of the present invention to provide a fixing device and an image forming apparatus that can provide heat resistance to a regulated portion and suppress wear of the regulated portion and/or the regulating portion.

In order to solve the above problems, the present invention provides a fixing device and an image forming apparatus according to the following first and second aspects.

(1) Fixing device according to the first aspect The fixing device according to the first aspect of the present invention includes a holding member fixed to a main body of the fixing device, and a fixing member provided rotatably around a rotation axis on the outer peripheral surface of the holding member. A fixing device comprising a belt, wherein a regulating portion is provided on the outer peripheral surface of the holding member facing the fixing belt, and a regulating portion is provided on the inner peripheral surface of the fixing belt facing the holding member. A regulated portion is provided, and the regulated portion restricts movement of the fixing belt in the direction of the rotational axis by coming into contact with the regulating portion, and the outer peripheral surface of the holding member has a periphery of the fixing belt. A step portion along the direction is provided, a heat resistant member is provided on the inner peripheral surface of the fixing belt, a sliding member is further provided on the heat resistant member, and the regulating portion is composed of the stepped portion, and the regulated portion is composed of the heat-resistant member and the slidable member, and at least a part of the side surface of the slidable member faces the stepped portion. It is characterized by doing.

(2) Fixing device of second aspect The fixing device of the second aspect according to the present invention includes a holding member fixed to a main body of the fixing device, and a fixing member provided rotatably around a rotation axis on the outer peripheral surface of the holding member. A fixing device comprising a belt, wherein a regulating portion is provided on the outer peripheral surface of the holding member facing the fixing belt, and a regulating portion is provided on the inner peripheral surface of the fixing belt facing the holding member. A regulated portion is provided, and the regulated portion restricts movement of the fixing belt in the direction of the rotational axis by coming into contact with the regulating portion, and the outer peripheral surface of the holding member has a periphery of the fixing belt. A step portion along the direction is provided, a sliding member is provided on the step portion, a heat resistant member is provided on the inner circumferential surface of the fixing belt, and a heat resistant member is provided on the inner peripheral surface of the fixing belt. The part is made of the sliding member, and the regulated part is made of the heat-resistant member, and the side surface of the heat-resistant member faces the side surface of the sliding member. Features.

(3) Image Forming Apparatus An image forming apparatus according to the present invention is characterized in that it includes the fixing device according to the present invention.

According to the present invention, it is possible to impart heat resistance to the regulated portion, and it is also possible to suppress wear of the regulated portion and/or the regulating portion.

1 is a sectional view showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention. 2 is a perspective view of a fixing device in the image forming apparatus shown in FIG. 1. FIG. 2A is a cross-sectional view taken along line AA shown in FIG. 2A. FIG. FIG. 2B is a perspective view of one end portion of the fixing belt of the fixing device shown in FIGS. 1 to 2B in the rotational axis direction, viewed from the front side. 2B is a perspective view of the other end portion of the fixing belt in the rotational axis direction of the fixing device shown in FIGS. 1 to 2B, viewed from the back side. FIG. FIG. 3 is a perspective view of the fixing belt supported by one holding member and the other holding member, viewed from the front side. FIG. 3 is a perspective view of an example of one holding member in the fixing device viewed from the front side. FIG. 3 is a perspective view of an example of the other holding member in the fixing device, viewed from the front side. FIG. 3 is a cross-sectional view schematically showing a regulated portion and a regulated portion in the fixing device. FIG. 3 is a perspective cross-sectional view schematically showing a regulated portion and a regulated portion in the fixing device. FIG. 7 is a cross-sectional view schematically showing a regulated portion and a regulated portion in a fixing device according to a second embodiment-1. FIG. 7 is a perspective cross-sectional view schematically showing a regulated portion and a regulated portion in a fixing device according to a second embodiment-1. FIG. 7 is a cross-sectional view schematically showing a regulated portion and a regulated portion in a fixing device according to a second embodiment-2. FIG. 7 is a perspective cross-sectional view schematically showing a regulated portion and a regulated portion in a fixing device according to a second embodiment-2. FIG. 7 is a perspective view of one of the holding members in the fixing device according to the third embodiment, viewed from the front side. FIG. 7 is a perspective view of the other holding member in the fixing device according to the third embodiment, viewed from the front side. FIG. 7 is a perspective cross-sectional view schematically showing a regulated portion and a regulating portion in a fixing device according to a third embodiment corresponding to the first embodiment. FIG. 7 is a perspective cross-sectional view schematically showing a regulated portion and a regulating portion in a fixing device according to a third embodiment corresponding to the second embodiment-1. FIG. 7 is a perspective cross-sectional view schematically showing a regulated portion and a regulating portion in a fixing device according to a third embodiment corresponding to the second embodiment-2. It is a perspective view of another example of one holding member seen from the right side of the front side. FIG. 7 is a perspective view of another example of the other holding member viewed from the right side of the front side.

Embodiments according to the present invention will be described below with reference to the drawings. In the following description, the same parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[Image forming device]
FIG. 1 is a sectional view showing a schematic configuration of an image forming apparatus 100 according to an embodiment of the present invention.

As shown in FIG. 1, the image forming apparatus 100 is a multifunction device having a copy function, a scanner function, a facsimile function, and a printer function, and transmits an image of a document G read by an image reading apparatus 102 to the outside. Further, the image forming apparatus 100 forms an image of the document G read by the image reading apparatus 102 or an image received from an external source on a sheet P such as a sheet of paper, which is a recording medium, in color or monochrome. Image forming apparatus 100 may be a monochrome image forming apparatus. Further, the image forming apparatus 100 may be a color image forming apparatus of another type.

A document feeding device 160 (automatic document feeding device) is provided above the image reading section 130 and is supported so as to be openable and closable with respect to the image reading section 130 . The image reading device 102 reads the document G conveyed by the document feeder 160. The document feeder 160 includes a document placement tray 161 on which a document G is placed, and a document ejection tray 162 on which the ejected document G is placed. The document feeder 160 sequentially conveys one or more documents G placed on the document placement tray 161 onto the document reading section 130b of the image reading section 130 one by one, and discharges them onto the document output tray 162. . Further, the image reading section 130 is provided with a document placement table 130a on which the document G is placed. The image reading device 102 reads the original G placed on the original placing table 130a. In the image forming apparatus 100, when the document feeding device 160 is opened, the document placing table 130a above the image reading section 130 is opened, so that the document G can be placed manually. The image reading section 130 reads the document G conveyed by the document feeder 160 with the scanning optical system 130c positioned at a reading position below the document reading section 130b, or scans the document G by scanning the scanning optical system 130c. The document G placed on the mounting table 130a is read to generate image data.

The image forming apparatus main body 101 includes an optical scanning device 1, a developing device 2, a photosensitive drum 3, a drum cleaning device 4, a charger 5, an intermediate transfer belt device 70, a secondary transfer device 11, a fixing device 12, and a sheet conveyance path S. , a paper feed cassette 18, and a sheet discharge tray 141.

The image forming apparatus 100 generates an image corresponding to a color image using each color of black (K), cyan (C), magenta (M), and yellow (Y), or a monochrome image using a single color (for example, black). data is handled. The image forming unit 50 of the image forming apparatus 100 is provided with four developing devices 2, a photosensitive drum 3, a drum cleaning device 4, and a charger 5 for forming four types of toner images. Four image stations Pa, Pb, Pc, and Pd are configured to correspond to cyan, magenta, and yellow.

The charger 5 uniformly charges the surface of the photoreceptor drum 3 to a predetermined potential. The optical scanning device 1 exposes the surface of the photoreceptor drum 3 to form an electrostatic latent image. The developing device 2 develops the electrostatic latent image on the surface of the photoreceptor drum 3 to form a toner image on the surface of the photoreceptor drum 3 . The drum cleaning device 4 removes and collects residual toner on the surface of the photoreceptor drum 3. Through the series of operations described above, toner images of each color are formed on the surface of each photoreceptor drum 3.

The intermediate transfer belt device 70 includes an intermediate transfer roller 6 , an endless intermediate transfer belt 71 , an intermediate transfer drive roller 72 , an intermediate transfer driven roller 73 , and a cleaning device 9 . Four intermediate transfer rollers 6 are provided inside the intermediate transfer belt 71 so as to form four types of toner images corresponding to each color. The intermediate transfer roller 6 transfers the toner images of each color formed on the surface of the photoreceptor drum 3 to an intermediate transfer belt 71 that rotates in a rotation direction C.

The intermediate transfer belt 71 is stretched around an intermediate transfer drive roller 72 and an intermediate transfer driven roller 73. In the image forming apparatus 100, the toner images of each color formed on the surface of each photoreceptor drum 3 are sequentially transferred and superimposed on the surface of the intermediate transfer belt 71 to form a color toner image on the surface of the intermediate transfer belt 71. do.

The secondary transfer device 11 forms a transfer nip TN between the secondary transfer roller 11a and the intermediate transfer belt 71, and pinches the sheet P conveyed through the sheet conveyance path S into the transfer nip TN. transport. When the sheet P passes through the transfer nip TN, the toner image on the surface of the intermediate transfer belt 71 is transferred by the secondary transfer device 11 and the sheet P is conveyed to the fixing device 12 . The cleaning device 9 removes and collects waste toner remaining on the surface of the intermediate transfer belt 71 without being transferred to the sheet P.

The fixing device 12 includes a fixing belt 31 and a pressure roller 32 that rotate with the sheet P sandwiched therebetween. The fixing device 12 fixes the toner image on the sheet P by sandwiching the sheet P on which the toner image has been transferred between the fixing belt 31 and the pressure roller 32 and applying heat and pressure to the sheet P. Although not shown in FIG. 1, the fixing device 12 includes components other than the fixing belt 31 and the pressure roller 32. Details of the fixing device 12 will be described later.

The paper feed cassette 18 is a cassette for storing sheets P used for image formation, and is provided below the optical scanning device 1. The sheet P is pulled out from the paper feed cassette 18 by the pickup roller 16 and conveyed to the sheet conveyance path S. The sheet P conveyed to the sheet conveyance path S passes through the secondary transfer device 11 and the fixing device 12, is conveyed to the discharge roller 17, and is discharged to the sheet discharge tray 141 in the discharge section 140. In the sheet conveyance path S, a conveyance roller 13, a registration roller 14, and a discharge roller 17 are arranged. The conveyance roller 13 urges the sheet P to be conveyed. The registration rollers 14 temporarily stop the sheet P and align the leading ends of the sheet P. The registration rollers 14 transport the once stopped sheet P in accordance with the timing of the toner image on the intermediate transfer belt 71.

In FIG. 1, the number of paper feed cassettes 18 is one, but the present invention is not limited to this, and a configuration may be provided in which a plurality of paper feed cassettes 18 are provided, and different types of sheets P may be stacked in each of them.

Further, when forming an image not only on the front side of the sheet P but also on the back side, the image forming apparatus 100 conveys the sheet P in the opposite direction from the discharge roller 17 to the sheet reversing path Sr. The image forming apparatus 100 turns the sheet P conveyed in the opposite direction upside down and guides it to the registration rollers 14 again. Further, the image forming apparatus 100 forms an image on the back side of the sheet P guided by the registration rollers 14 in the same manner as on the front side, and carries it out to the sheet discharge tray 141.

[Fusing device]
FIG. 2A is a perspective view of fixing device 12 in image forming apparatus 100 shown in FIG. 1. FIG. FIG. 2B is a cross-sectional view taken along line AA shown in FIG. 2A.

The fixing device 12 includes a support member 33 provided inside the fixing belt 31, a fixing pad 34, a sliding sheet 35, a heat source 36, a reflective plate 37, a temperature detection section 38 (thermopile in this example), a peeling plate 39, and a thermostat. 40.

The fixing belt 31 is an endless flexible belt, and is formed into a belt shape. The fixing belt 31 is provided so as to be rotatable around a rotation axis α along a direction orthogonal to the conveyance direction H of the sheet P.

The fixing belt 31 includes an elastic layer (for example, a silicone rubber layer) of a predetermined thickness (for example, about 100 μm to 300 μm) on a base of metal such as nickel or polyimide (PI) with a predetermined thickness (for example, about 30 μm to 100 μm). A mold release layer (e.g., fluororesin layer) with a thickness (e.g., about 20 μm to 30 μm) is formed on top of the mold release layer, specifically, a silicone rubber upper layer with a PFA tube, or a fluorocarbon resin. An example is one coated with In this example, the fixing belt 31 has a 40 μm thick nickel base coated with silicone rubber, and a PFA tube provided on the silicone rubber upper layer, and has a total thickness of 300 μm. Although the inner diameter of the fixing belt 31 is not limited thereto, in this example, it is 30 mm.

The fixing pad 34 is made of resin, for example, and is formed into a long plate shape extending along the rotation axis α direction (rotation axis direction W) of the fixing belt 31 , and has a long plate shape extending between the fixing pad 34 and the fixing belt 31 . A sliding sheet 35 is provided.

The support member 33 is a member that supports the fixing pad 34 while pressing the sliding sheet 35 against the inner peripheral surface of the fixing belt 31. Both ends of the support member 33 in the rotation axis direction W are fixed to a fixing frame (not shown). A reflective plate 37 is provided on the surface of the support member 33 on the heat source 36 side.

The heat source 36 is a member for heating the fixing belt 31 and extends along the rotation axis direction W of the fixing belt 31. The heat source 36 can be, for example, a lamp heater such as a halogen lamp. The fixing belt 31 is heated to a predetermined fixing temperature (for example, 160° C. to 250° C., 160° C. in this example) by a heat source 36. Therefore, not only the fixing belt 31 but also the sliding sheet 35 and the like have heat resistance to the above temperature.

Pressure roller 32 is arranged at a position facing fixing pad 34 with fixing belt 31 in between. The pressure roller 32 rotates around a rotational axis parallel to the rotational axis α of the fixing belt 31 and extends parallel to the fixing belt 31 . The pressure roller 32 forms a fixing nip FN between the fixing belt 31 and the fixing belt 31 by pressing the fixing belt 31 toward the fixing pad 34 (sliding sheet 35). Specifically, the pressure roller 32 can be constructed of a roller member having a cylindrical core made of metal such as aluminum, and the surface of which is covered with an elastic material such as rubber.

Driving force from a drive source (not shown) such as a motor is transmitted to the pressure roller 32 via a gear or the like (not shown). The pressure roller 32 is rotationally driven by receiving a driving force from a driving source. The fixing belt 31 is driven to rotate in a first rotation direction R1 that is opposite to the second rotation direction R2 of the pressure roller 32 as the pressure roller 32 is rotated. That is, the pressure roller 32 forms a fixing nip FN by contacting the outer circumferential surface of the fixing belt 31, and transmits driving force to the fixing belt 31 via the fixing nip FN, thereby tightening the fixing belt 31. Rotate driven.

The temperature detection unit 38 detects the surface temperature of the fixing belt 31. In the fixing device 12, the temperature of the heat source 36 is controlled so that the fixing belt 31 reaches the fixing temperature (160° C. in this example) based on the temperature detected by the temperature detection unit 38.

The peeling plate 39 is disposed on the downstream side of the fixing nip portion FN in the conveyance direction H of the sheet P, and prevents the sheet P from wrapping around the fixing belt 31.

The thermostat 40 cuts off power supply to the heat source 36 when the heat source 36 becomes abnormally heated. Specifically, the thermostat 40 is electrically connected to a power line (not shown) that supplies power to the heat source 36, and is configured to directly cut off the power supply to the heat source 36.

The temperature detection unit 38 is fixed to the image forming apparatus main body 101 (main body frame) (see FIG. 1). The temperature detection unit 38 detects the surface temperature of the fixing belt 31 in a non-contact manner. The thermostat 40 is fixed to the fixing device main body 12a (main body frame). The thermostat 40 operates to cut off the power supply to the heat source 36 when a predetermined reaction temperature (operating temperature, rated temperature) is reached.

3A and 3B are perspective views of end portions of one side W1 and the other side W2 in the rotational axis direction W of the fixing belt 31 of the fixing device 12 shown in FIGS. 1 to 2B, viewed from the front side and the back side, respectively. It is a diagram. FIG. 4 is a perspective view of the fixing belt 31 supported by one holding member 41a (41) and the other holding member 41b (41), viewed from the front side. 5A and 5B are perspective views of an example of one holding member 41a (41) and an example of the other holding member 41b (41) of the fixing device 12, respectively, viewed from the front side. Further, FIG. 6A is a cross-sectional view schematically showing the regulated portion 42 and the regulating portion 43 in the fixing device 12. FIG. 6B is a perspective cross-sectional view schematically showing the regulated portion 42 and the regulated portion 43 in the fixing device 12.

As shown in FIGS. 3A to 5B, the fixing device 12 includes a holding member 41 and a fixing belt 31 (see FIG. , see FIG. 3B). The holding member 41 is fixed to the fixing device main body 12a (main body frame) (see FIG. 2B).

In this example, the holding members 41 are a pair of holding members 41a and 41b, which hold both ends of the inner circumferential surface 311 of the fixing belt 31 in the rotational axis direction W. Among the pair of holding members 41a and 41b, one holding member 41a holds both ends of one side W1 (front side, operation side) in the rotational axis direction W of the inner peripheral surface 311 of the fixing belt 31, and the other holding member 41b holds both ends of the inner peripheral surface 311 of the fixing belt 31 on the other side W2 (rear side) in the rotational axis direction W. As shown in FIG.

As shown in FIGS. 5A and 5B, one holding member 41a and the other holding member 41b each have holding parts 41a1 and 41b1, and protrusion parts 41a2 and 41b2 connected to holding parts 41a1 and 41b1. are doing. The holding parts 41a1 and 41b1 hold the inner circumferential surface 311 of the fixing belt 31 on the outer circumferential surface 411. The holding portions 41a1 and 41b1 are circular arc-shaped portions that are partially cut out in the circumferential direction R. The shape of the holding portions 41a1 and 41b1 may be an arc of 180 degrees or more, more preferably an arc of 270 degrees or more, and in this example, the shape is an arc of about 270 degrees. The protrusions 41a2, 41b2 extend outward in the rotational axis direction W from the outer ends of the holding parts 41a1, 41b1 in the rotational axis direction W, and extend in the radial direction with respect to the outer circumferential surface 411 of the holding parts 41a1, 41b1. protrudes outward. The protrusions 41a2 and 41b2 have wall surfaces 41a3 and 41b3 that face the end surface 31a of the fixing belt 31 (see FIG. 6B).

As a material for the holding members 41 (41a, 41b), a heat-resistant resin material [for example, liquid crystal polymer (LCP)] can be used.

At least one (one or both) of the pair of holding members 41a and 41b (in this example, one holding member 41a) has a stepped portion 43a along the circumferential direction R of the fixing belt 31. In the example, side surfaces 43a1, 43a1) of the recess extending in the circumferential direction R (see FIGS. 5A and 6A) are provided. As shown in FIGS. 6A and 6B, at least one (one or both) of the pair of holding members 41a and 41b (one holding member 41a in this example) is attached to the inner peripheral surface 311 of the fixing belt 31. A regulated portion 42 is provided facing each other.

In the fixing device 12, the movement of the fixing belt 31 in the rotational axis direction W is regulated by the regulated part 42 (slidable member 42b in this example) coming into contact with the regulating part 43.

(First embodiment)
As shown in FIGS. 6A and 6B, a heat-resistant member 42a is provided on the inner peripheral surface 311 of the fixing belt 31, and a sliding member 42b is further provided on the heat-resistant member 42a. The regulating portion 43 is composed of a stepped portion 43a. The regulated portion 42 includes a heat-resistant member 42a and a slidable member 42b. At least a portion (all or a portion) of the side surfaces 42b1, 42b1 of the slidable member 42b opposes the step portion 43a (side surface 43a1, 43a1). In this example, the fixing belt 31 and the heat-resistant member 42a are bonded to each other using a heat-resistant adhesive (adhesive), and the heat-resistant member 42a and the sliding member 42b are bonded to each other using a heat-resistant adhesive (adhesive). It is glued.

According to the fixing device 12 according to the first embodiment, even if the fixing belt 31 moves in the rotation axis direction W when rotating around the rotation axis α, the regulated The portion 42 comes into contact with a restriction portion 43 provided on the outer circumferential surface 411 of the holding member 41, thereby restricting movement of the fixing belt 31 in the rotational axis direction W. A heat-resistant member 42 a constituting the regulated portion 42 is provided on the inner circumferential surface 311 of the fixing belt 31 . Therefore, the regulated portion 42 can be made heat resistant. Further, at least a part of the side surfaces 42b1, 42b1 of the sliding member 42b, which is provided on the heat-resistant member 42a and constitutes the regulated portion 42, is connected to the step portion 43a (side surface 43a1, 43a1) which constitutes the regulating portion 43. opposite. Therefore, when the fixing belt 31 rotates around the rotation axis α, at least a portion of the side surfaces 42b1, 42b1 of the slidable member 42b (restricted portion 42) is rotated by the side surfaces 43a1, 43a1 of the step portion 43a (regulating portion 43). Even if the sliding member 42b comes into contact with the sliding member 42b, the sliding property (wear resistance) of the sliding member 42b suppresses the wear of the sliding member 42b (regulated portion 42) and/or the stepped portion 43a (regulating portion 43). Can be done.

Here, as the heat-resistant member, for example, a heat-resistant resin member having a glass transition temperature of 80 degrees or higher can be used, including but not limited to, polyphenylene sulfide (PPS), polyether ether ketone ( Examples include heat-resistant resin members such as PEEK (Poly Ether Ether Ketone) and liquid crystal polymer (LCP). Further, as the sliding member, for example, a sliding resin member having a coefficient of friction (coefficient of dynamic friction) of 0.1 or less can be used, and is not limited thereto, such as polytetrafluoroethylene (PTFE). Sliding resin members such as fluororesin can be exemplified. The same applies to the second embodiment and third embodiment described later.

By the way, the slidability of the heat-resistant member 42a is smaller than the slidability of the slidable member 42b. Therefore, when the heat-resistant member 42a comes into contact with the holding member 41 when the fixing belt 31 rotates around the rotation axis α, the heat-resistant member 42a and/or the holding member 41 are likely to be damaged by friction. For this reason, it is preferable that the heat-resistant member 42a not come into contact with the holding member 41.

In this regard, in this embodiment, the width d1 (see FIG. 6A) (5.00 mm in this example) in the rotational axis direction W of the sliding member 42b is the width d2 (5.00 mm in this example) of the sliding member 42b in the rotational axis direction W. (see FIG. 6A) (for example, 4.00 mm or more and less than 5.00 mm, in this example, 4.00 mm). Both ends of the sliding member 42b in the rotation axis direction W protrude beyond both ends of the heat resistant member 42a in the rotation axis direction W. Specifically, the protrusion amounts d3, d3 (see FIG. 6A) on both sides of the sliding member 42b from the heat-resistant member 42a are predetermined protrusion amounts (0.50 mm, 0.50 mm in this example). Also, the gaps d4, d4 (see FIG. 6A) on both sides between the side surfaces 42b1, 42b1 of the slidable member 42b and the stepped portion 43a (side surfaces 43a1, 43a1) (0.50 mm, 0.50 mm in this example) are , from the gaps d5, d5 on both sides between the end surfaces 31a, 31a on both sides of the fixing belt 31 and the wall surfaces 41a3, 41b3 of the pair of holding members 41a, 41b (see FIG. 6B, only one side is shown in FIG. 6B). It's also small. That is, the gaps d4, d4 on both sides and the gaps d5, d5 on both sides are such that even if the side surfaces 42b1, 42b1 of the sliding member 42b abut against the stepped portion 43a (side surfaces 43a1, 43a1), the end surfaces 31a, 31a of the fixing belt 31 The pair of holding members 41a, 41b is dimensioned so as not to come into contact with the wall surfaces 41a3, 41b3. In the illustrated example, the fixing belt 31 is located at a predetermined position (center) in the rotation axis direction W, and at this time, the gaps d4, d4 on both sides are equal, and the gaps d5, d5 on both sides are equal.

By doing this, even if the fixing belt 31 moves in the rotation axis direction W when rotating around the rotation axis α, the slidable member 42b can be brought into contact with the holding member 41, and therefore the heat resistant member 42a contact with the holding member 41 can be effectively prevented. Thereby, damage to the heat-resistant member 42a and/or the holding member 41 due to friction can be suppressed.

By the way, since the fixing belt 31 reaches a high temperature, if the fixing belt 31 comes into contact with the holding member 41 when the fixing belt 31 rotates around the rotation axis α, the holding member 41 is likely to be damaged by the heat. For this reason, it is preferable to prevent the fixing belt 31 from coming into contact with the holding member 41.

In this regard, in the present embodiment, the top surface 42b2 of the slidable member 42b on the opposite side to the fixing belt 31, and the bottom surface 41c of the holding member 41 adjacent to the stepped portion 43a and facing the slidable member 43b. The distance d6 (see FIG. 6A) (0.25 mm in this example) is the distance d7 (see FIG. 6A) between the inner peripheral surface 311 of the fixing belt 31 and the outer peripheral surface 411 of the holding member 41. In the example, the diameter is smaller than 2.50 mm).

By doing so, even if the fixing belt 31 moves in the rotation axis direction W when rotating around the rotation axis α, it is possible to effectively prevent the fixing belt 31 from contacting the holding member 41. Thereby, damage to the holding member 41 due to heat can be suppressed.

In this embodiment, the outer circumferential surface 411 of the holding member 41 is provided with a recess extending in the circumferential direction R. The regulated portion 42 is inserted into the recessed portion, and the regulated portion 42 inserted therethrough is allowed to move in the circumferential direction R. The stepped portion 43a is configured at two locations: side surfaces 43a1 and 43a1 on both sides in the rotational axis direction W of the recessed portion. That is, the recessed portion is composed of the stepped portion 43a (side surfaces 43a1, 43a1) and the bottom surface 41c of the holding member 41. The recesses (43a1, 43a1, 41c) can be provided in one of the holding members 41a and 41b in the rotation axis direction W (one holding member 41a in this example). .

In this way, even if the recesses (43a1, 43a1, 41c) are provided in one of the holding members (one holding member 41a in this example), when the fixing belt 31 rotates around the rotational axis α, the rotational axis When the fixing belt 31 moves in the direction W, side surfaces 43a1 and 43a1 on both sides in the rotational axis direction W of the recesses (43a1, 43a1, 41c) in the holding member 41 cause the fixing belt 31 to be fixed on one side W1 and on the other side W2 in the rotational axis direction W. Movement in both areas can be regulated.

In the first embodiment, the stepped portion 43a is provided on one holding member 41a (41), but may be provided on the other holding member 41b (41). In this case, the regulated portion 42 is provided on the other side W2 of the inner peripheral surface 311 of the fixing belt 31 in the rotational axis direction W.

(Second embodiment)
<Second embodiment-1>
FIG. 7A is a cross-sectional view schematically showing the regulated portion 42 and the regulating portion 43 in the fixing device 12 according to the second embodiment-1. FIG. 7B is a perspective cross-sectional view schematically showing the regulated portion 42 and the regulated portion 43 in the fixing device 12 according to the second embodiment-1.

The fixing device 12 according to the second embodiment-1 has the same configuration as the fixing device 12 according to the first embodiment except that the regulated portion 42 and the regulating portion 43 are changed in the fixing device 12 according to the first embodiment. be. Therefore, in the second embodiment-1, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

A step portion 44 extending along the circumferential direction of the fixing belt 31 is provided on the outer peripheral surface 411 of the holding member 41 . Slidable members 43b, 43b are provided on the stepped portion 44 (side surfaces 44a, 44a). A heat-resistant member 42a is provided on the inner peripheral surface 311 of the fixing belt 31. The regulating portion 43 is composed of slidable members 43b, 43b. The regulated portion 42 is composed of a heat-resistant member 42a. Side surfaces 42a1 and 42a1 of the heat-resistant member 42a face side surfaces 43b1 and 43b1 of the sliding member 43b. In this example, the stepped portion 44 and the slidable members 43b, 43b are bonded to each other with a heat-resistant adhesive member (adhesive).

According to the fixing device 12 according to the second embodiment-1, even if the fixing belt 31 moves in the rotation axis direction W when rotating around the rotation axis α, the The regulated portion 42 comes into contact with a regulating portion 43 provided on the outer circumferential surface 411 of the holding member 41, thereby regulating movement of the fixing belt 31 in the rotational axis direction W. A heat-resistant member 42 a constituting the regulated portion 42 is provided on the inner circumferential surface 311 of the fixing belt 31 . Therefore, the regulated portion 42 can be made heat resistant. Further, the side surfaces 42a1, 42a1 of the heat-resistant member 42a constituting the regulated portion 42 are provided on the stepped portion 44 (side surfaces 44a, 44a), and the side surfaces 43b1, 43b1 of the sliding member 43b constituting the regulating portion 43 are opposite. Therefore, when the fixing belt 31 rotates around the rotation axis α, the side surfaces 42a1, 42a1 of the heat-resistant member 42a (regulated portion 42) contact the side surfaces 43b1, 43b1 of the sliding member 43b (regulating portion 43). Even when they are in contact with each other, the sliding properties (wear resistance) of the sliding member 43b suppress the wear of the heat-resistant member 42a (regulated part 42) and/or the sliding member 43b (regulating part 43). can.

In this embodiment, sliding members 43b, 43b are provided on both the stepped portion 44 (side surfaces 44a, 44a) and the bottom surface 41c of the holding member 41 adjacent to the stepped portion 44 and facing the heat-resistant member 42a. , 43b are provided.

By the way, since the fixing belt 31 reaches a high temperature, when the fixing belt 31 contacts the holding member 41 and the sliding member 43b when the fixing belt 31 rotates around the rotation axis α, the holding member 41 and the sliding member 43b is easily damaged by heat. For this reason, it is preferable to prevent the fixing belt 31 from coming into contact with the holding member 41 and the slidable member 43b.

In this regard, in the present embodiment, the difference between the top surface 42a2 of the heat-resistant member 42a on the side opposite to the fixing belt 31 and the slidable member 43b (bottom surface 43b2) provided on the bottom surface 41c of the holding member 41 is A distance d11 (see FIG. 7A) (0.25 mm in this example) is provided between the inner circumferential surface 311 of the fixing belt 31, the outer circumferential surface 411 of the holding member 41, and the stepped portion 44 (side surfaces 44a, 44a). It is smaller than the distance d12 (see FIG. 7A) (1.00 mm in this example) between the fixing belt 31 and the opposing top surfaces 43b3, 43b3 of the slidable members 43b, 43b. In this example, the outer peripheral surface 411 of the holding member 41 and the top surfaces 43b3, 43b3 of the slidable members 43b, 43b are flush with each other.

This effectively prevents the fixing belt 31 from contacting the holding member 41 and the sliding member 42b even if the fixing belt 31 moves in the rotation axis direction W when rotating around the rotation axis α. be able to. Thereby, damage to the holding member 41 and the slidable member 42b due to heat can be suppressed.

Specifically, the gaps d13, d13 (see FIG. 7A) on both sides between the side surfaces 42a1, 42a1 (see FIG. 7A) of the heat-resistant member 42a and the side surfaces 43b1, 43b1 of the sliding member 43b (see FIG. 7A) (0.50 mm in this example) , 0.50 mm) is smaller than the gaps d5, d5 on both sides (see FIG. 6B) between the end surfaces 31a, 31a on both sides of the fixing belt 31 and the wall surfaces 41a3, 41b3 of the pair of holding members 41a, 41b. That is, the gaps d13, d13 on both sides and the gaps d5, d5 on both sides are such that even if the side surfaces 42a1, 42a1 of the heat-resistant member 42a abut against the side surfaces 43b1, 43b1 of the sliding member 43b, the end surfaces 31a on both sides of the fixing belt 31 , 31a are dimensioned so that they do not come into contact with the wall surfaces 41a3, 41b3 of the pair of holding members 41a, 41b. In the illustrated example, the fixing belt 31 is located at the center in the rotation axis direction W, and at this time, the gaps d13, d13 on both sides are equal, and the gaps d5, d5 on both sides are equal. The width d14 (see FIG. 7A) of the heat-resistant member 42a in the rotation axis direction W is a predetermined distance (3.00 mm in this example). The thickness d15 (see FIG. 7A) of the heat-resistant member 42a in the radial direction V is a predetermined distance (2.00 mm in this example). The width d14 and thickness d15 of the heat-resistant member 42a are set to values that can maintain desired strength and heat resistance. The thicknesses d16, d16, d16 (see FIG. 7A) of the sliding member 43b are predetermined distances (0.50 mm, 0.50 mm, 0.50 mm in this example). The thickness d16 of the slidable member 43b is set to a value that can maintain desired strength.

<Second embodiment-2>
FIG. 8A is a cross-sectional view schematically showing the regulated portion 42 and the regulating portion 43 in the fixing device 12 according to the second embodiment-2. FIG. 8B is a perspective cross-sectional view schematically showing the regulated portion 42 and the regulated portion 43 in the fixing device 12 according to the second embodiment-2.

The fixing device 12 according to the second embodiment-2 is the fixing device 12 according to the second embodiment-1 in which the sliding member 43b is increased in height in the radial direction V.

By the way, the slidability of the holding member 41 is smaller than that of the slidable member 42b. Therefore, when the fixing belt 31 contacts the holding member 41 when the fixing belt 31 rotates around the rotation axis α, the fixing belt 31 and/or the holding member 41 are likely to be damaged due to friction. For this reason, it is preferable to prevent the fixing belt 31 from coming into contact with the holding member 41.

In this regard, in the present embodiment, the slidable member 43b protrudes from the outer peripheral surface 411 of the holding member 41 toward the fixing belt 31 side. Between the top surface 42a2 of the heat-resistant member 42a on the side opposite to the fixing belt 31 and the sliding member 43b provided on the bottom surface 41c of the holding member 41 adjacent to the stepped portion 44 and facing the heat-resistant member 42a. The distance d11 (see FIG. 8A) (1.00 mm in this example) is the distance between the inner circumferential surface 311 of the fixing belt 31 and the top surfaces 43b3, 43b3 of the sliding member 43b facing the fixing belt 31. d121 (see FIG. 8A) (0.25 mm in this example). Specifically, the protrusion amount d17 of the slidable member 43b from the outer circumferential surface 411 of the holding member 41 is greater than 0 mm, and the distance between the inner circumferential surface 311 of the fixing belt 31 and the outer circumferential surface 411 of the holding member 41 is greater than 0 mm. It is smaller than the distance d122 (see FIG. 8A).

By doing so, even if the fixing belt 31 moves in the rotation axis direction W when rotating around the rotation axis α, it is possible to effectively prevent the fixing belt 31 from contacting the holding member 41. Thereby, damage to the fixing belt 31 and/or the holding member 41 due to friction can be suppressed.

(Third embodiment)
9A and 9B are perspective views of one holding member 41a (41) and the other holding member 41b (41) in the fixing device 12 according to the third embodiment, respectively, viewed from the front side. 10A to 10C schematically illustrate a regulated portion 42 and a regulated portion 43 in a fixing device 12 according to a third embodiment corresponding to the first embodiment, second embodiment-1, and second embodiment-2, respectively. FIG. Note that in FIGS. 10A to 10C, end portions on both sides in the rotational axis direction W are shown in one diagram.

The fixing device 12 according to the third embodiment is the same as the fixing device 12 according to the first embodiment except that the step portion 43a is configured at two locations in the fixing device 12 according to the first embodiment, second embodiment-1, and second embodiment-2. The configuration is the same as that of the fixing device 12 according to the second embodiment. Therefore, in the third embodiment, similar configurations in the first embodiment, second embodiment-1, and second embodiment-2 are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, both the one holding member 41a (41) and the other holding member 41b (41) are provided with a stepped portion 43a that is lower on the outside in the rotation axis direction W and higher on the inside. ing. In this way, when the step portions 43a, 43a are provided on both the one holding member 41a (41) and the other holding member 41b (41), the regulated portions 42, 42 are provided on both sides in the rotational axis direction W of the fixing belt 31. can be provided.

(Common embodiment from the first embodiment to the third embodiment)
In this regard, in the first to third embodiments, the widths d1 and d14 of the regulated part 42 in the rotation axis direction W are the insertion widths of the regulated part 42 into the regulation part 43 in the rotation axis direction W (d1+d4+d4). , (d14+d13+d13).

By doing so, when the fixing belt 31 rotates around the rotation axis α and comes into contact with the holding member 41, the frequency of sliding contact of the regulated portion 42 with the regulating portion 43 can be suppressed. Thereby, wear of the regulated portion 42 and/or the regulating portion 43 can be suppressed.

In the first to third embodiments, the regulated portion 42 may be formed on the inner peripheral surface 311 of the fixing belt 31 over the entire circumference. In other words, the regulated portion 42 is formed continuously (endlessly) along the circumferential direction R on the inner circumferential surface 311 of the fixing belt 31 .

In this way, movement of the fixing belt 31 in the rotational axis direction W can be reliably regulated by the regulated portion 42.

Here, in the first to third embodiments, the holding parts 41a1 and 41b1 of one holding member 41a (41) and the other holding member 41b (41) are circular arcs with a part cut out in the circumferential direction R. Although it is set as a shaped part, it may be made into a cylindrical shaped part.

FIGS. 11A and 11B are perspective views of another example of one holding member 41a (41) and another example of the other holding member 41b (41), respectively, viewed from the right side of the front side.

The holding portion 41a1 of one holding member 41a (41) shown in FIG. 11A and the holding portion 41b1 of the other holding member 41b (41) shown in FIG. 11B are cylindrical portions.

Note that one holding member 41a (41) shown in FIG. 11A shows a configuration example of the first embodiment, second embodiment-1, and second embodiment-2; In the case of Embodiment-1 and Second Embodiment-2, the other holding member 41b (41) having the cylindrical holding portion 41b1 is the same as that of the first embodiment, Second Embodiment-1, and Second Embodiment-2. An example of the configuration may be as follows. Further, the other holding member 41b (41) shown in FIG. 11B shows an example of the third embodiment, but in this case, one holding member 41a (41) having a cylindrical holding portion 41a1 also has a cylindrical holding portion 41a1. The configuration example is similar to the third embodiment.

In the first to third embodiments, when the holding portions 41a1 and 41b1 of the pair of holding members 41a and 41b are circular arc-shaped portions with a portion cut out in the circumferential direction R, the regulating portion 43 ( It is preferable that the step portions 43a, 44) are formed entirely on the outer peripheral surfaces 411, 411 of the holding portions 41a1, 41b1. In other words, the regulating portions 43 (43a, 44) are preferably formed continuously along the circumferential direction R between one end and the other end in the circumferential direction R on the outer circumferential surface 411 of the holding portions 41a1, 41b1. .

By doing so, the movement of the fixing belt 31 in the rotational axis direction W can be reliably restricted by the restriction portion 43.

Further, in the first to third embodiments, when the holding portions 41a1, 41b1 of the pair of holding members 41a, 41b are cylindrical portions, the regulating portion 43 (step portions 43a, 44) is It is preferable that they are formed on the outer peripheral surfaces 411, 411 of the holding parts 41a1, 41b1 over the entire circumference. In other words, the regulating portions 43 (43a, 44) are preferably formed continuously (in an endless manner) along the circumferential direction R on the outer peripheral surfaces 411, 411 of the holding portions 41a1, 41b1.

By doing so, the movement of the fixing belt 31 in the rotational axis direction W can be reliably restricted by the restriction portion 43.

Note that the regulated portion 42 may be partially formed at one or more locations on the inner circumferential surface 311 of the fixing belt 31. And/or the restriction portion 43 may be partially formed at one or more locations on the outer peripheral surfaces 411, 411 of the holding portions 41a1, 41b1. Moreover, when the regulated part 42 is partially formed at one place or multiple places, and the regulating part 43 is partially formed at one place or multiple places, and when the regulated part 42 is partially formed at one place or multiple places, When the holding portions 41a1 and 41b1 are arc-shaped portions, the regulated portion 42 is partially formed at one or more locations in the first rotation direction R1. A taper may be provided at the downstream end, and/or a taper may be provided at the upstream end in the first rotation direction R1 of the regulating portion 43 partially formed at one or more locations.

The present invention is not limited to the embodiments described above, and can be implemented in various other forms. Therefore, such embodiments are merely illustrative in all respects, and should not be interpreted in a limiting manner. The scope of the present invention is indicated by the claims, and is not restricted in any way by the main text of the specification. Furthermore, all modifications and changes that come within the scope of equivalents of the claims are intended to be within the scope of the present invention.

100 Image forming apparatus 12 Fixing device 12a Fixing device main body 31 Fixing belt 311 Inner peripheral surface 31a End surface 41 Holding member 411 Outer peripheral surface 41a One holding member 41a Holding member 41a1 Holding section 41b Other holding member 41b1 Holding section 41c Bottom surface 42 Regulated Part 42a Heat-resistant member 42a1 Side surface 42b Sliding member 42b1 Side surface 43 Regulating portion 43a Step portion 43a1 Side surface 43b Sliding member 43b1 Side surface 44 Step portion 44a Side surface R Circumferential direction V Radial direction W Rotation axis direction W1 One side W2 Other side α Rotation axis

Claims (12)

A fixing device comprising: a holding member fixed to a fixing device main body; and a fixing belt rotatably provided around a rotation axis on an outer peripheral surface of the holding member,
A regulating portion is provided on the outer circumferential surface of the holding member to face the fixing belt, and a regulated portion is provided on the inner circumferential surface of the fixing belt to face the holding member, and the regulating portion is provided on the inner circumferential surface of the fixing belt to face the holding member. restricting movement of the fixing belt in the rotational axis direction by contacting the restricting portion;
The outer peripheral surface of the holding member is provided with a stepped portion along the circumferential direction of the fixing belt,
A heat resistant member is provided on the inner peripheral surface of the fixing belt, and a sliding member is further provided on the heat resistant member,
The regulating portion is configured with the stepped portion,
The regulated portion is composed of the heat resistant member and the slidable member,
A fixing device characterized in that at least a portion of a side surface of the slidable member faces the stepped portion. The fixing device according to claim 1,
The width of the sliding member in the rotational axis direction is larger than the width of the heat-resistant member in the rotational axis direction, and both ends of the sliding member in the rotational axis direction are aligned with the rotational axis of the heat-resistant member. A fixing device characterized by protruding beyond both ends in a direction. The fixing device according to claim 1 or 2,
The distance between the top surface of the slidable member opposite to the fixing belt and the bottom surface of the holding member adjacent to the stepped portion and facing the slidable member is the distance between A fixing device characterized in that the distance is smaller than the distance between an inner circumferential surface and the outer circumferential surface of the holding member. A fixing device comprising: a holding member fixed to a fixing device main body; and a fixing belt rotatably provided around a rotation axis on an outer peripheral surface of the holding member,
A regulating portion is provided on the outer circumferential surface of the holding member to face the fixing belt, and a regulated portion is provided on the inner circumferential surface of the fixing belt to face the holding member, and the regulating portion is provided on the inner circumferential surface of the fixing belt to face the holding member. restricting movement of the fixing belt in the rotational axis direction by contacting the restricting portion;
The outer peripheral surface of the holding member is provided with a stepped portion along the circumferential direction of the fixing belt,
A slidable member is provided in the stepped portion,
A heat-resistant member is provided on the inner peripheral surface of the fixing belt,
The regulating portion is composed of the slidable member,
The regulated portion is made of the heat resistant member,
A fixing device characterized in that a side surface of the heat-resistant member faces a side surface of the sliding member. The fixing device according to claim 4,
The sliding member is provided on both the step portion and the bottom surface of the holding member adjacent to the step portion and facing the heat-resistant member,
The distance between the top surface of the heat-resistant member opposite to the fixing belt and the sliding member provided on the bottom surface of the holding member is the distance between the inner circumferential surface of the fixing belt and the sliding member provided on the bottom surface of the holding member. A fixing device characterized in that the distance between the outer circumferential surface of the holding member and the top surface of the slidable member provided at the stepped portion facing the fixing belt is smaller. The fixing device according to claim 4 or 5,
The slidable member protrudes from the outer circumferential surface of the holding member toward the fixing belt, and extends from the top surface of the heat-resistant member on the side opposite to the fixing belt, and adjacent to the stepped portion of the holding member. The distance between the heat-resistant member and the sliding member provided on the bottom surface facing the fixing belt is determined by the distance between the inner peripheral surface of the fixing belt and the top surface of the sliding member facing the fixing belt. A fixing device characterized in that the fixing device is larger than the distance between the fixing devices. The fixing device according to claim 1, claim 2, claim 4, or claim 5,
The outer peripheral surface of the holding member is provided with a recess extending in the circumferential direction,
The fixing device is characterized in that the stepped portion is formed at two locations on both side surfaces of the recessed portion in the direction of the rotation axis. The fixing device according to claim 1, claim 2, claim 4, or claim 5,
A fixing device characterized in that a width of the regulated portion in the rotation axis direction is smaller than an insertion width of the regulated portion into the regulation portion in the rotation axis direction. The fixing device according to claim 1, claim 2, claim 4, or claim 5,
The fixing device characterized in that the regulated portion is formed on the inner peripheral surface of the fixing belt over the entire circumference. The fixing device according to claim 1, claim 2, claim 4, or claim 5,
The holding member has a holding portion that holds the inner circumferential surface of the fixing belt on the outer circumferential surface,
The holding portion is a circular arc-shaped portion,
The fixing device according to claim 1, wherein the regulating portion is formed entirely on the outer circumferential surface of the holding portion. The fixing device according to claim 1, claim 2, claim 4, or claim 5,
The holding member has a holding portion that holds the inner circumferential surface of the fixing belt on the outer circumferential surface,
The holding part is a cylindrical part,
The fixing device according to claim 1, wherein the regulating portion is formed on the outer peripheral surface of the holding portion over the entire circumference. An image forming apparatus comprising the fixing device according to claim 1, claim 2, claim 4, or claim 5.

Images