JP2023154440A - Fixing device - Google Patents

Abstract

To suppress the positional deviation of a fixing belt in the width direction.SOLUTION: Provided is a fixing device that forms a nipple part together with a pressure rotor via a fixing belt. At the nipple part, the fixing belt and the pressure rotor apply heat and pressure to a recording material carrying a toner image, thereby fixing the toner image to the recording material. The fixing device has a suspension member that suspends the fixing belt, and also has a movement mechanism that, when the pressure rotor is located at a position to release a pressing force to the fixing belt, causes movement to a press position where the suspension member presses the fixing belt from the inner circumferential face toward the outer circumferential face of the fixing belt and a release position where the pressing force exerted to the fixing belt by the suspension member is released.SELECTED DRAWING: Figure 3

Description

The present invention relates to a fixing device that fixes a toner image onto a recording material.

Conventionally, an electrophotographic image forming apparatus includes a fixing device that fixes a toner image formed on a recording material to the recording material.

As one type of fixing device, a configuration using a fixing belt that is an endless belt is known (Patent Document 1). The fixing belt is suspended by a plurality of members including a heating roller having a heating source. The heating roller heats the fixing belt. One of the members that suspends the fixing belt includes a nip forming member. The nip forming member forms a nip portion together with the pressure rotating body via the fixing belt. When the recording material carrying the toner image is conveyed to the nip portion, heat and pressure are applied to the recording material to fix the toner image on the recording material.

Further, in the fixing device described in Patent Document 1, it is described that the position of the fixing belt is detected by a photosensor via a flag. Based on the detection results of the photo sensor, the widthwise position of the fixing belt is controlled by tilting the steering roller that suspends the fixing belt. In order to control the position of the fixing belt in the width direction of the fixing belt, a steering roller is pressed against the fixing belt.

JP2021-33204

In a fixing device configured such that a fixing belt is suspended by a plurality of suspension members, vibrations are applied to the fixing device when the fixing device is transported. The vibration causes the fixing device to shake. This may cause the suspended fixing belt to shift in the width direction.

Therefore, an object of the present invention is to suppress the positional shift of the fixing belt in the width direction.

In view of the above problems, the fixing device according to the present invention includes a rotatable endless fixing belt, a heating roller that contacts an inner circumferential surface of the fixing belt and applies heat to the fixing belt, and a suspension member that comes into contact with the inner peripheral surface of the fixing belt;
A pressure rotating body that presses the fixing belt, and the pressure rotating body can move between a position where it presses the fixing belt and a position where it releases pressure on the fixing belt, and the pressure rotating body presses the fixing belt. A nip forming member forms a nip portion together with a pressure rotating body, and in the nip portion, the fixing belt and the pressure rotating body apply heat and pressure to the recording material carrying the toner image, thereby transferring the toner image to the recording material. When the fixing belt is fixed to the fixing belt and the pressure rotating body is located at a position where it releases the pressure on the fixing belt, the suspension member presses the fixing belt from the inner circumferential surface of the fixing belt toward the outer circumferential surface. The present invention is characterized in that it has a moving mechanism that moves the suspension member to a pressing position, which is a position where the fixing belt is pressed, and a release position, which is a position where the suspension member releases the pressure on the fixing belt.

According to the fixing device of the present invention, it is possible to suppress misalignment of the fixing belt in the width direction.

FIG. 1 is a cross-sectional view of an image forming apparatus in this embodiment. FIG. 3 is a cross-sectional view of the fixing device in this embodiment. FIG. 3 is a partial perspective view of the fixing device in the first embodiment. FIG. 3 is a side view of one end side of the fixing device in the first embodiment. FIG. 3 is a perspective view of a fixing device in a second embodiment. FIG. 7 is a partial perspective view of one end side of the fixing device in the second embodiment.

<Example 1>
<Image forming device>
A first embodiment of this embodiment will be described. Although a full-color copying machine equipped with a plurality of photoconductor drums has been described as this embodiment, the present invention can also be applied to monochrome copying machines and printers equipped with one photoconductor drum. Therefore, this embodiment is not limited to full color laser beam printers. First, an outline of the image forming operation will be explained. FIG. 1 is a main sectional view showing the overall configuration of an image forming apparatus 100.

<Image forming device>
This image forming apparatus 100 transports a recording material P transported from a recording material storage section 103 to an image forming section 110, and forms a toner image on the recording material P. After that, the image forming apparatus 100 transports the recording material P on which the toner image has been formed in the image forming section 110 to the fixing device 200, and applies heat and pressure to remove the unfixed toner on the recording material P. Fix it on P. The recording material P is, for example, a sheet of paper, OHP, or the like.

The image forming apparatus 100 includes an image forming section 110. The image forming section 110 forms yellow, magenta, cyan, and black toner images on the intermediate transfer belt 115. The image forming section 110 forms four types of images along the moving direction of the intermediate transfer belt 115: a yellow image forming section 120a, a magenta image forming section 120b, a cyan image forming section 120c, and a black image forming section 120d. 110 is arranged.

The image forming process will be described using the yellow image forming section 120a as an example. A photosensitive drum 111 serving as an image carrier rotates counterclockwise in FIG. 1 . The primary charger 112 charges the photoreceptor drum 111 to a uniform surface potential. The laser unit 113 has a light source that outputs laser light, and forms a latent image on the photoreceptor drum 111. The developing device 114 uses a developer containing toner to develop the latent image formed on the photoreceptor drum 111 to form a toner image. Toner images are formed in the other image forming units 120b to 120d in the same way as in 120a.

The toner images formed by the image forming units 120a, 120b, 120c, and 120d are transferred onto the intermediate transfer belt 115. The transfer roller 116 transfers the toner image on the intermediate transfer belt 115 onto the recording material P conveyed from the recording material storage section 103.

The fixing device 200 fixes the toner image transferred to the recording material P onto the recording material P by applying heat and pressure to the recording material P. The fixing device 200 includes a fixing belt 201, a pressure roller 202, and the like.

In the case of single-sided printing, the image forming apparatus 100 discharges the recording material P, on which image formation has been completed, through the image forming section 110 and the fixing device 200, to the outside by guiding it to the discharge path 139 using the flapper 132. The flapper 132 is a guiding member that guides the recording material P that has passed through the image forming section 110 and the fixing device 200 to the conveyance path 134 or to the outside of the image forming apparatus 100 .

On the other hand, in the case of double-sided printing, the image forming apparatus 100 reverses the recording material P that has been printed on one side and conveys it to the image forming section 110 again. Specifically, the flapper 132 guides the fixed recording material P to a conveyance path 134 and conveys it to a reversing section 136. When the reversal sensor 135 detects the rear end of the recording material P, the flapper 133 switches the conveyance direction of the recording material P to the conveyance path 137. The image forming apparatus 100 transports the inverted recording material P via the transport path 137 to the image forming section 110 and further to the fixing device 200 again. The recording material P that has been printed on both sides is guided to a discharge path 139 by a flapper 132 and discharged to the outside.

The operation unit 180 includes a display screen and selection keys. The operation unit 180 displays the status of the image forming apparatus 100 on a display screen and accepts operation instructions from an operator (user) using selection keys.

The control board 150 includes a control section 151 and a memory 152, and controls each unit within the image forming apparatus 100 described above. The control unit 151 sends output signals to each electrical component in order to operate the electrical component at a desired timing and with a necessary amount of control, based on detection signals input from each sensor and information stored in the memory 152. Output to. Therefore, it is this control section 151 that actually controls the electrical components. The memory 152 stores information data necessary for controlling each unit section, and the control section 151 reads and writes the information data stored in the memory 152.

Next, details of the configuration of the fixing device in this embodiment will be described using FIGS. 2 and 3. FIG. 2 is a sectional view of a fixing device according to an embodiment of the present invention, and FIG. 3 is a partial perspective view of the fixing device 200.

<Fixing device>
FIG. 2 shows a schematic diagram of the overall configuration of a belt heating type fixing device 200 according to an embodiment of the present invention. In FIG. 2, the recording material P is conveyed from right to left. The fixing device 200 includes a heating unit 210 having a heat source and a pressure roller 202 as a pressure rotating body. First, the heating unit 210 will be explained. The heating unit 210 includes a fixing belt (hereinafter referred to as belt) 201 as an endless rotatable heating rotating body. A nip forming member (hereinafter referred to as a pad) 203 that forms a nip portion, a heating roller 204 having a halogen heater, and a steering roller 205 that controls the position of the belt are in contact with the inner peripheral surface of the belt 201. . The belt 201 is thereby suspended. The pad 203 forms a nip portion N with the pressure roller via the belt 201.

The belt 201 has thermal conductivity, heat resistance, etc., and has a thin cylindrical shape. This embodiment has a three-layer structure including a base layer, an elastic layer around the outer periphery of the base layer, and a releasable layer around the outer periphery of the base layer. The base layer has a thickness of 60 μm and is made of polyimide resin (PI). Silicone rubber with a thickness of 300 μm is used for the elastic layer. The releasable layer has a thickness of 30 μm and is made of PFA (tetrafluoroethylene/perfluoroalkoxyethylene copolymer resin) as a fluororesin. The pad 203 is a member that comes into pressure contact with the pressure roller 202 via the belt 201 to form a nip portion N of a predetermined width in the recording material conveyance direction. The belt 201 has a substantially rectangular cross section and is a long member along the width direction of the belt 201 . The material of the pad 203 needs to be heat resistant, and is made of LCP (liquid crystal polymer) resin.

A lubricating sheet 207 whose surface is coated with PTFE and silicone oil S (hereinafter referred to as oil S) are interposed between the pad 203 and the belt 201, so that the belt 201 is smoothly attached to the pad 203. It is designed to slide. The lubricating sheet 207 is formed by coating the surface of a polyimide base material with a thickness of 70 μm with PTFE. Note that the lubricating sheet 207 is arranged to improve the sliding properties between the pad 203 and the fixing belt 201, and can be substituted by applying a coating or the like to the surface layer of the pad 203 to improve sliding properties instead of the sliding sheet 207. It is possible.

The pressure roller 202 is a roller having an elastic layer formed around the outer periphery of the shaft and a release layer formed around the outer periphery. The shaft is made of stainless steel, the elastic layer is 5 mm thick and made of conductive silicone rubber, and the release layer is 50 μm thick and made of PFA as a fluororesin. The pressure roller 202 is axially supported by the fixing frame 380 of the fixing device 200, has a gear fixed to one end thereof, is connected to a drive source M via the gear, and is rotationally driven. The belt 201 is rotated in the R direction by being supported by the rotating pressure roller 202 and pad 203. Further, the pressure roller 202 is held by bearings at both ends, and can be moved to a position where it presses the belt 201 to form a nip N and a position where the pressure on the belt 201 is released by means of an attachment/detachment means (not shown). . At the position where the pressure roller 202 releases the pressure on the belt 201, the pressure roller 202 may be separated from the belt 201. It is assumed that the pressure on the belt 201 is released and the restraint force of the belt 201 on the belt 201 is weakened. When the nip portion N is formed between the pressure roller 202 and the belt 201, a pressing force of about 1000N acts.

If the pressure roller 202 forms a nip portion N while the rotation of the pressure roller 202 is stopped and this condition is left untreated, strain will occur in a portion of the rubber portion in the circumferential direction. As a result, uneven rotation of the pressure roller 202 and uneven surface properties may occur. Therefore, when the image forming apparatus is not used, for example when the image forming apparatus is transported from the manufacturer to the user, it is necessary to hold it in the position where the above-mentioned pressure is released (the state shown in FIG. 2). In this embodiment, in order to remove the fixing device 200 from the image forming apparatus 100, when a cover (not shown) is opened and when the power of the image forming apparatus 100 is turned off, the pressure roller 202 is It is moved to a separate position.

The oil supply roller 208 is formed by impregnating silicone oil into a roll-shaped member wound with a nonwoven fabric having a thickness of 100 μm. The oil supply roller 208 is brought into contact with the inner surface of the fixing belt 201 at 3.0 N by a pressure spring 209, and is supported by the frame of the heating unit 210 so as to be rotatable.

The oil S applied as a lubricant between the pad 203 and the belt 201 deteriorates as the fixing device 200 operates and decreases due to leakage to the outside. If the oil S between the pad 203 and the belt 201 cannot be held, the sliding resistance between the pad 203 and the belt 201 increases, which may cause problems such as poor rotation of the belt 201. The oil supply roller 208 comes into contact with the belt 201, thereby making it possible to supply the oil S to the inner peripheral surface of the belt 201. This makes it possible to maintain the oil S present between the belt 201 and the pad 203 (sliding sheet 207) for a longer period of time, and to maintain stable operation of the fixing device 200.

The stay 206 is a reinforcing member that is disposed inside the pad 203 (on the side opposite to the sliding sheet 207), backs up the pad 203, and has rigidity and is long in the width direction of the belt 201. The material used is drawn SUS304 material with a wall thickness of 3 mm, and its strength is ensured by forming it into a hollow shape with a square cross section. The stay 206 provides strength to the pad 203 and secures the pressing force at the nip portion N when the pad 203 is pressed against the pressure roller 202. Note that the material of the stay 206 is not limited to stainless steel as long as its strength can be ensured.

The heating roller 204 is a stainless steel pipe with a thickness of 1 mm and an outer diameter of 80 mm. A halogen heater (not shown) is disposed inside the roller and can generate heat up to a predetermined temperature. The belt 201 is heated by a heating roller 204 and controlled to a predetermined target temperature depending on the paper type based on temperature detection by a thermistor.

A steering roller 205 serving as a suspension member that suspends the belt 201 suspends the fixing belt 201 and is supported by the steer frame 213 via a steer bearing portion 221 . In this embodiment, the steering roller 205 is constructed by forming silicone rubber with a thickness of 200 μm on the surface layer of a hollow stainless steel roll portion with an outer diameter of 20 mm. Steering roller 205 is rotatably supported by steer roller shaft 223 via a bearing.

The steer roller shaft 223 is supported at both ends by a pair of steer bearings 221. The steer bearing part 221 is made of a resin material that can be used in high-temperature environments, such as PPS, and is movably attached along the side wall of the box-shaped steer frame 213. In addition, the steering roller 205 is biased toward the fixing belt 201 by pressing the steer shaft bearing portion 221 by the spring 211 supported by the steer frame 213 . Thereby, the fixing belt 201 is suspended with tension between the steering roller 205, the heating roller 204, and the pad 203. In this suspended state, the steering roller 205 is in contact with the fixing belt 201 with a force of 20 N by the spring 211.

The steer frame 213 rotates with respect to the frame of the heating unit 210 about the rotation shaft 212, thereby changing the alignment of the steering roller 205 with respect to other suspension members. Thereby, a tension difference is generated before and after the fixing belt 201, and the position of the belt 201 in the main scanning direction is controlled.

In the separated state where the fixing belt 201 and the pressure roller 202 are separated, the contact force between the pad 203 and the fixing belt 201 is weak. It will be held in the state. When the image forming apparatus is subjected to vibrations during transportation, the heating roller 204 and steering roller 205 also vibrate, and they also move in the main scanning direction, which is the width direction of the belt 201. At this time, the fixing belt 201 is held by the heating roller 204 with a large binding force and vibrates. However, compared to the heating roller 204, the steering roller 205, which has a smaller contact area with the belt 201, has a smaller binding force for restraining the belt 201. Then, due to the vibration, the position of the belt 201 in contact with the steering roller 205 shifts. Under the influence of the restraining force of the steering roller 205, a relative positional shift with respect to the heating roller 204 occurs. For example, if the belt 201 deviates significantly in the width direction, the positional deviation will be detected and an error will occur.

By using the tension release means in this embodiment, it is possible to reduce the pressing force of the steering roller 205 against the fixing belt 201, so it is possible to suppress the displacement of the fixing belt 201 caused by the above-mentioned difference in restraint force. Become. The details are described below.

The movement mechanism of the suspension member in this embodiment will be explained. FIG. 4 is a partial perspective view of the fixing device 200 for explaining a state in which the tension of the steering roller 205 is released by a steering lock arm 222, which will be described later. In order to achieve the states shown in FIGS. 3 and 4, it is necessary to remove the fixing device 200 from the image forming apparatus 100 and perform operations on the casing, such as removing the cover. Therefore, the pressure roller 202 is moved to a position where the pressure on the fixing belt 201 is released.

Steering lock arms 222 are held at both ends of the steer frame 213 in the longitudinal direction of the steering roller 205 . During image formation, the belt 201 must be suspended under tension. If image formation is performed with the tension loosened, the belt 201 will cause waving, paper wrinkles, and the like. Therefore, during image formation, the steering roller 205 presses against the belt 201. This causes the belt 201 to be suspended under tension. The position of the steering roller 205 pressing against the belt 201 is defined as a pressing position. The direction in which the steering roller 205 presses the belt 201 is from the inner peripheral surface of the belt 201 to the outer peripheral surface. The direction from the inner circumferential surface of the belt 201 to the outer circumferential surface means that there is only a component of force directed from the inner circumferential surface of the belt 201 toward the outer circumferential surface.

The steer lock arm 222 is formed of a wire spring with a wire diameter of 1 mm, and is rotatably attached to the steer frame 213. The support portion 221 is formed with a mounting surface 221a on which the steer lock arm 222 is mounted. By hanging the steer lock arm 222 on the mounting surface 221a while pressing the steering roller 205 in the opposite direction to the pressing direction by the spring 211, the steering roller 205 is held at a position removed from the position where the fixing belt 201 is suspended (released). position). This makes it possible to reduce the contact force against the fixing belt 201 and weaken the tension applied to the fixing belt 201 (the state shown in FIG. 4). In this embodiment, mounting surfaces 221a are provided at both ends of the steering roller 205. When the steering roller 205 is placed in the release position, the steer lock arms 222 are attached to the attachment surfaces 221a at both ends. Thereby, the tension can be weakened at both ends of the steering roller 205.

In this embodiment, the steering roller 205 can be moved in the direction away from the 5 mm belt 201 (in the direction of the arrow in FIG. 4) by hanging the steering lock arm 222 on the mounting surface 221a. Thereby, the steering roller 205 is separated from the belt 201. A position where the tension applied to the belt 201 by the steering roller 205 is weakened is defined as a release position. With the steering roller 205 located at the release position, the belt 201 can be easily removed and attached, so the fixing belt 201 can be replaced. As described above, when the steering roller 205 is located at the release position, it is in a state separated from the belt 201. However, it is not limited to this. The release position may be a position where the force with which the steering roller 205 presses the belt 201 is weaker than the pressing position. In other words, the inner peripheral surface of the belt 201 and the steering roller 205 may be in contact with each other. If the position is away from the belt 201, there is no force to press the belt 201, so it is better if the position is away from the belt 201.

When the steering roller 205 is located at the release position, the tension of the belt 201 decreases, so that the belt 201 sags due to its own weight. Therefore, when comparing the pressed position and the released position, the contact area between the belt 201 and the heating roller 204 is larger at the released position.

As described above, by positioning the steering roller 205 in the release position before transporting the fixing device, it is possible to suppress misalignment of the belt 201 that occurs during transport. Therefore, the position of the steering roller 205 before use of the fixing device is the release position.

Oil S is applied inside the fixing belt 201. The oil S is set to have a kinematic viscosity of 50 to 500 CST at high temperatures in order to satisfy the desired sliding performance at high temperatures during fixing operation. Since the heating unit 210 described above does not operate when the image forming apparatus is transported from the manufacturer to the user, the viscosity of the oil S increases. Therefore, the heating roller 204 and steering roller 205 that suspend the fixing belt 201 are in close contact with the fixing belt 201 via the oil S. Since the area where the fixing belt 201 contacts the heating roller 204 is wider than the area where the fixing belt 201 contacts the steering roller 205, the binding force of the heating roller 204 is also larger.

<Example 2>
A second embodiment of the present invention will be described. Note that the configurations and operations of the image forming apparatus 100 and the fixing device 200 are substantially the same as those in the first embodiment, and therefore description thereof will be omitted.

The details of the fixing device configuration in this embodiment will be described. FIG. 5 is a perspective view of a fixing device according to an embodiment of the present invention, and FIG. 6 is a partial perspective view of the fixing device 200. In order to achieve the states shown in FIGS. 5 and 6, it is necessary to remove the fixing device 200 from the image forming apparatus 100 and expose the housing portion such as the cover. Therefore, the pressure roller 202 is moved to a separated position away from the fixing belt 201.

When the cover of the image forming apparatus 100 is opened, the fixing device 200 is configured to be removable. In the fixing device 200, a fixing cover 250 covers a steering roller 205 suspended from a fixing belt 201. When maintaining the internal parts of the fixing device 200, the fixing cover 250 can be opened to access the fixing belt 201 and the like.

The fixing cover 250 is formed of a cover part 251 made of resin and a metal plate part 252 that holds the cover part. An opening 302 is formed in the cover portion 251 and the plate portion 252 so that the fixing member 301 can be connected and attached from the outside of the fixing device 200. FIG. 5 illustrates a state in which the fixing member 301 is attached. The fixing member 301 is an iron plate-like member, and is formed with a locking portion 301a that presses the steer bearing 221 and a regulating portion 301b that contacts the plate portion 250b. A guide hole 252a through which the fixing member 301 passes and a contact portion 252b that contacts the lock portion 301a are formed in the opening of the plate portion 250b.

When attaching the fixing member 301, the fixing member 301 is first passed through the aforementioned guide hole 252a, and the pressing surface 221c of the steer bearing 221 is pressed by the lock portion 301a. Next, the fixing member 301 is slid while the steering roller 205 is pressed in a direction opposite to the pressing direction by the spring 211, and the regulating portion 301b abuts against the contact portion 252b. Thereby, the spring force of the spring 211 that presses the steering roller 205 is received by the regulating portion 252b of the plate portion 252, and it becomes possible to hold the steering roller 205 in a pressed state.

In this embodiment, the steering roller 205 can be moved in the direction away from the 5 mm belt 201 (in the direction of the arrow in FIG. 4) by restraining the steer bearing 221 with the fixing member 301. Thereby, the steering roller 205 is separated from the belt 201. A position where the tension applied to the belt 201 by the steering roller 205 is weakened is defined as a release position. With the steering roller 205 located at the release position, the belt 201 can be easily removed and attached, so the fixing belt 201 can be replaced. As described above, when the steering roller 205 is located at the release position, it is in a state separated from the belt 201. However, it is not limited to this. The release position may be a position where the force with which the steering roller 205 presses the belt 201 is weaker than the pressing position. In other words, the inner peripheral surface of the belt 201 and the steering roller 205 may be in contact with each other. If the position is away from the belt 201, there is no force to press the belt 201, so it is better if the position is away from the belt 201. The effect of separating the steering roller 205 is the same as in the first embodiment.

Removal of the fixing member 301 can be performed in the reverse order as described above, but it can also be done by separating the fixing member 301 from the steer bearing 221 by, for example, opening the fixing cover.

Further, in this embodiment, a method for attaching the fixing member 301 using the fixing cover 250, which is a component of the fixing device 200, has been described, but it is sufficient to press and hold the steer bearing 221 with the fixing member 301. For example, the same effect can be obtained in the frame of the fixing device 200 or the cover of the image forming apparatus 100 if there is an opening for attaching the fixing member 301 and a fixing part.

100 Image forming apparatus 200 Fixing device 201 Fixing belt 202 Pressure roller 203 Pad 204 Heating roller 205 Steering roller 210 Heating unit 222 Steering lock arm 223 Steering roller shaft

Claims (7)

A rotatable endless fixing belt,
a heating roller that contacts an inner peripheral surface of the fixing belt and applies heat to the fixing belt;
a suspension member that comes into contact with the inner peripheral surface of the fixing belt together with the heating roller;
a pressure rotating body that presses the fixing belt;
The pressure rotating body can move between a position where it presses the fixing belt and a position where it releases the pressure on the fixing belt,
a nip forming member that forms a nip portion together with the pressure rotating body via the fixing belt;
In the nip portion, the fixing belt and the pressure rotating body apply heat and pressure to the recording material carrying the toner image to fix the toner image on the recording material,
When the pressure rotating body is located at a position where it releases pressure on the fixing belt, the suspension member is located at a position where it is pressing the fixing belt from the inner circumferential surface toward the outer circumferential surface of the fixing belt. A fixing device comprising a moving mechanism for moving the suspension member between a certain pressing position and a release position, which is a position where the suspension member releases the pressure on the fixing belt. The fixing device according to claim 1, wherein the suspension member is located at the release position before the fixing device is used. The fixing device according to claim 1, wherein the moving mechanism is provided at both ends of the suspension member in the longitudinal direction of the suspension member. The fixing device according to claim 1, wherein the suspension member is a steering roller that controls the position of the fixing belt in the width direction of the fixing belt. When the suspension member is located at the pressing position, an area in which the heating roller and the fixing belt are in contact is larger than an area in which the suspension member and the fixing belt are in contact. The fixing device according to claim 1. The contact area between the heating roller and the fixing belt is smaller when the suspension member is located at the pressing position than when the suspension member is located at the release position. The fixing device according to claim 1. The fixing device according to claim 1, wherein when the suspension member is located at the release position, the suspension member is in contact with an inner circumferential surface of the fixing belt.

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