JP2003091188A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device where frictional resistance between a pressure imparting member and a belt member (especially, belt member having a rough inner surface) is made low and the low frictional resistance is kept. SOLUTION: This fixing device is equipped with a roll member (thermal fixing roll 2), a belt member (endless belt 3) rotating and traveling while coming into contact with the roll member, a heating source for heating at least either the roll member or the belt member, the pressure imparting member (pad member 4) arranged on the inside of the belt member in a non-rotating state and making the endless belt press-contact with the roll and powder (powder 101) intervening between the belt member and the pressure imparting member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device for heating and fixing a toner image in an image forming apparatus such as an electrophotographic copying machine or a laser printer, and more particularly to a fixing device having a pressure applying member in a belt nip type fixing device. Regarding the device.

[0002]

2. Description of the Related Art In order to reduce the size, improve performance, and save power of electrophotographic equipment, a fixing device is disclosed in, for example, Japanese Unexamined Patent Publication No.
A belt nip type as described in No. 262903 has been developed. The fixing device is, for example, arranged such that a fixing roll (roll member) is heated and rotated, and an endless belt (belt member) is brought into contact with the fixing roll to be driven to rotate, and a recording paper on which a toner image is formed is placed between them. The toner image is passed through and heat-fixed. At this time, a pressure applying member (pressure pad) arranged in a non-rotating state is provided inside the endless belt in order to form a nip and press-contact the endless belt with the fixing roll.

In the above publication, a polyimide resin film is used as an endless belt, and polytetrafluoroethylene (PTF) is used as a pressure applying member (pressure pad).
A member covered with a glass fiber sheet impregnated with E) is described. Since the pressure applying member (pressure pad) always slides on the inner surface of the rotating endless belt, a material that is hard to wear and has low frictional resistance is required. Further, it is described that a lubricant is applied to the inside of the endless belt in order to improve slidability. Silicone oil or the like is used as the lubricant.

However, when the pressure applying member (pressure pad) is used for a long time in the material having the above structure,
There is a problem that the frictional resistance gradually increases due to the abrasion of PTFE or the lubricant flowing out to the peripheral portion. In particular,
If the inner surface of the endless belt is rough, sliding with the pressure applying member (pressure pad) may cause abnormal noise.
A method of reducing the frictional resistance between the pressure applying member (pressure pad) and the endless belt and maintaining the frictional resistance is desired.

In addition, a method for producing a polyimide resin film is usually to apply a solution of a polyimide resin precursor on a substrate, dry the solvent, and then heat-cure it. To form an endless belt, a columnar or cylindrical core is used as a substrate, and the polyimide resin film is cured and then removed. In order to facilitate removal at that time or to prevent deformation of the coating film during curing, it is preferable to roughen the surface of the core body, but as a result, the inner surface of the endless belt formed becomes rough. In particular, when such an endless belt having a rough inner surface is used, the above-mentioned problems relating to slidability remarkably appear, and improvement is required.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the various problems in the prior art and achieve the following objects. That is, it is an object of the present invention to provide a fixing device that reduces the frictional resistance between a pressure applying member and a belt member (particularly, a belt member having a rough inner surface), and maintains it.

[0007]

The above problems can be solved by the following means. That is, the fixing device of the present invention includes a roll member, a belt member that rotates in contact with the roll member, a heating source that heats at least one of the roll member and the belt member, and the inside of the belt member. A fixing device comprising: a pressure applying member that is arranged in a non-rotating state and that presses the belt member against the roll member; and a powder that is interposed between the belt member and the pressure applying member. It is a device.

In the fixing device of the present invention, since the powder is interposed between the belt member and the pressure applying member, the powder avoids the direct contact between the pressure applying member and the belt member, and the powder is interposed. As a result, the contact area is reduced, so that the frictional resistance between the pressure applying member and the belt member can be reduced, and it can be maintained for a long period of time.

In the fixing device of the present invention, the powder is preferably spherical particles. Further, the powder is preferably polytetrafluoroethylene (PTFE) particles. Furthermore, the size of the powder has an average particle size of 0.1 to 10 μm.
It is preferable that it is m.

In the fixing device of the present invention, the base material of the belt member is preferably a polyimide resin. Further, as a combination of the inner surface roughness of the belt member and the size of the powder, the center line average roughness Ra ₇₅ of the inner surface of the belt member is 0.1 to 5.0 μm, and the size of the powder is average. The particle size is preferably 0.1 to 10 μm.

In the fixing device of the present invention, as the combination of the inner surface roughness of the belt member and the size of the powder, the center line average roughness Ra ₇₅ of the surface of the pressure applying member is 0.1 to 5.0 μm.
m, and the size of the powder is 0.1 to 0.1
It is preferably 10 μm.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a fixing device of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic sectional view showing an example of the fixing device of the present invention. As shown in FIG. 1, the fixing device 1 includes a heat fixing roll (roll member) 2 having a built-in heat source, and an endless belt (belt member) stretched between three supporting rolls and pressed against the heat fixing roll 2. 3, and a pad member (pressure applying member) 4 that is in contact with the inner surface side of the endless belt 3 and presses the endless belt 3 along the surface of the heat fixing roll 2 constitutes a main part. Further, as shown in FIG. 2, powder is further interposed between the endless belt 3 and the pad member 4.

In the fixing device 1, the endless belt 3 also rotates as the heating and fixing roll 2 rotates. By passing the sheet 19 between the endless belt 3 and the heat fixing roll 2, the unfixed toner 20 on the sheet 19 is fixed. In such a fixing method, the heat conducted from the heating and fixing roll 2 is not easily dissipated, and the amount of heat taken from the heating and fixing roll 2 is small even when the rotation of the endless belt 3 is started. Therefore, it is possible to achieve power saving by being low in heat loss, which is economical, and also to reduce the temperature drop in the belt nip, thereby improving the fixing property of the toner.

In the fixing device 1, as shown in FIG. 2, the powder 1 is further provided between the pad member 4 and the endless belt 3.
By interposing 01, direct contact between the pad member 4 and the endless belt 3 is avoided, and the contact area is reduced through the powder 101, so that the frictional resistance between the pad member 4 and the endless belt 3 is reduced. , And it can last longer.

The powder 101 will be described. Powder 101
As a method of interposing between the pad member 4 and the endless belt 3, the powder 101 is directly attached to the surface of the pad member 4 (sliding surface with the endless belt 3) before the endless belt 3 is mounted on the fixing device. It can be done by dusting. The powder 101 is also preferably used together with various lubricants such as silicone oil. In this case, for example, the powder 101 is dispersed in a lubricant in advance, and the powder 101 is applied (lubricated) to the surface of the pad member 4 (sliding surface with the belt member). It can be interposed between the pad member 4 and the endless belt 3.

The powder 101 is specifically, for example, polytetrafluoroethylene (PTFE) particles, glass particles, aluminum nitride particles, acrylic particles, styrene particles, titanium oxide particles, crystalline polyamide particles, crystalline polyester particles. Etc. Among these, PT
FE particles are preferable from the viewpoints of durability, strength (hardness), and more effectively reducing frictional resistance. Each of these particles is a particle containing each material as a main component, and may be a particle containing an additive and the like as necessary. In particular, since it is preferable that the powder 101 has lubricity from the viewpoint of reducing frictional resistance, the PTF as the powder 101 is also preferable from this viewpoint.
E particles are preferred.

The shape of the powder 101 is spherical.
This is preferable from the viewpoint that the contact area between the pad member 4 and the endless belt 3 can be reduced, frictional resistance can be further reduced, and abnormal noise can be reduced. Specifically, the shape of the powder 101 is preferably a spheroidization rate of 60 to 100%.

The size of the powder 101 depends on the base material (inner layer) of the endless belt 3, the material of the surface of the pad member 4 and the surface roughness thereof, but is about 0.1 to 10 μm, and more preferably. , 0.2 to 5 μm, and more preferably 0.5 to 2 μm. If the size of the powder 101 is smaller than the above range, the effect of reducing the frictional resistance may not be sufficiently obtained, and if it is larger than the above range,
Not only is the effect of reducing frictional resistance not sufficiently obtained,
Abnormal noise may occur.

The endless belt 3 will be described. The endless belt 3 is arranged so as to come into pressure contact with the surface of the heat fixing roll 2 over a predetermined nip width. This endless belt 3 has, for example, a thickness of 75 μm and a width of 34 μm.
It is made of a polyimide resin film of 0 mm and a perimeter of 214 mm, and is formed by three rolls 15, 16 and 17.
It is stretched with a tension of about 5 kgf. The surface of the endless belt 3 may have various functional layers (for example, a release layer and an elastic layer made of a fluororesin), but a film made of a polyimide resin is preferable as the base material (inner layer), and others. , Polyamideimide, polybenzimidazole, polyetheretherketone, polyphenylenesulfide, polyetherimide and the like.

The endless belt 3 usually has a center line average roughness Ra ₇₅ of about 0.1 to 1.5 μm (preferably 0.2 to 1.5 μm) on its inner surface, and the inner surface is particularly preferable. When the endless belt 3 having a rough surface is used, the powder 101 uniformly enters the concave portion on the inner surface of the belt, and
The powder 101 separated from the belt nip portion (the contact portion between the inner surface of the endless belt 3 and the pad member 4 (however, the powder 101 intervenes)) is conveyed by the convex portion (fine protrusion) on the inner surface of the belt, and the powder 101 is again fed. Since it intervenes in the belt nip portion, it is possible to effectively and stably reduce the frictional resistance over a long period of time. Further, when the endless belt 3 having a rough inner surface is used, a very high abnormal noise is often generated. However, by interposing the powder 101, the generation of such an abnormal noise can be suppressed. Specifically as the magnitude of the relationship between the endless belt 3 center line average roughness Ra ₇₅ of the inner surface and the powder 101 exert such effects more effectively, the endless belt 3 inside surface center line average roughness Ra ₇₅ of 0.1-5.0 μm (preferably 0.2-1.5 μm,
More preferably 0.5 to 1.2 μm), and powder 10
It is preferable that the average particle size of 1 is 0.1 to 10 μm (preferably 0.5 to 2 μm). Here, the center line average roughness Ra ₇₅ means JIS B 0601-198.
It is a scale of surface roughness based on 2 (indicated here as Ra), and can be determined by using, for example, a surface shape measuring microscope (manufactured by Keyence Corporation). The same applies hereinafter.

When the polyimide resin film is used as the endless belt 3 as described above, the manufacturing method is usually a cylindrical or cylindrical core body used as the substrate, and the polyimide resin film is cured and then removed. .
In order to facilitate removal at that time or to prevent deformation of the coating film during curing, it is preferable to roughen the surface of the core body, and the inner surface thereof tends to be rough. When the endless belt 3 having the polyimide resin coating film thus produced as a base material (inner layer) is used, in particular, by interposing powder, the friction resistance is effectively reduced over a long period of time effectively, and abnormal noise is generated. Can be suppressed.

The endless belt 3 usually has a dynamic friction coefficient of about 0.06 to 0.08 on its inner surface (depending on the material type), but has a high dynamic friction coefficient of 0.09 to 0.12. Even if the endless belt 3 having the dynamic friction coefficient of the inner surface is used, the friction resistance between the endless belt 3 and the endless belt 3 can be reduced by interposing the powder 101 between the endless belt 3 and the pad member 4. It can last for a long time. Further, when the endless belt 3 whose inner surface has a very high dynamic friction coefficient is used, a very large abnormal noise is often generated, but such an abnormal noise can also be suppressed.

The diameter of the three rolls 15, 16 and 17 is
For example, they are set to 23 mm, 18 mm, and 18 mm, respectively. In addition, the above three rolls 15, 16, 17
Among them, the pressure roll 15 and the inlet roll 16 are made of, for example, stainless steel or the like in a crown shape, and the steering roll 17 is made of stainless steel or the like having a surface coated with silicon rubber, and has a cylindrical or columnar member. Is formed in.

The pressure roller 15 has a pressure of 60 kgf at the exit of the belt nip.
It is arranged so as to be in pressure contact with the surface of. The endless belt 3 is configured to be driven to rotate while being in pressure contact with the heating and fixing roll 2. Therefore, the elastic layer 6 of the heat fixing roll 2 is deformed, strain ε is generated on the surface thereof, and the recording medium can be separated due to its own rigidity. In the figure, reference numeral 18 denotes a halogen lamp for heating the endless belt 3, which is arranged inside the inlet roll 16 as needed. Also,
Reference numeral 19 denotes a recording element such as a recording sheet carrying an unfixed toner image 20.

The pad member will be described. Roll 15
A pad member 4 as a pressure applying member for pressing the endless belt 3 against the surface of the heat fixing roll 2 with a predetermined pressure is disposed between the roller 16 and the roll 16. As shown in FIG. 2, the pad member 4 includes a shim 22 made of a synthetic resin such as polyphenylene sulfide (PPS) on the surface of a base plate 21 made of a metal such as stainless steel.
Via the support plate 2 made of metal such as stainless steel
The elastic layer 24 laminated on the upper surface 3 is arranged. Further, the entire surface of the pad member 4 is covered with a pad sheet 25 as a sheet-shaped member. As the material for forming the pad sheet 25, any material can be used as long as it has heat resistance and abrasion resistance. Examples of the material for forming the pad sheet 25 include polyimide (PI), polybenzimidazole (PBI), polybenzoxazole (PB).
O), polyamideimide (PAI), peak (Pee)
k) and the like. The support plate 23 on which the elastic layer 24 is laminated is fixed to the base plate 21 via the shims 22 by the mounting screws 26 provided at both ends in the longitudinal direction. Further, the pad member 4 is pressed against the heating and fixing roll 2 with a pressing force of, for example, 50 kgf by a compression coil spring (not shown) arranged on the base plate 21 side. The base plate 21 is, for example, 20 mm in width (running direction of the belt), 360 mm in length (perpendicular to the paper surface),
A 7.5 mm thick stainless steel product is used.
The elastic layer 24 is made of silicone sponge (foam of silicone rubber) having a rubber hardness of 20 ° and has a thickness of 5 mm.
belongs to. In addition, the rubber hardness here is measured by an Asker C type sponge rubber hardness meter manufactured by Kobunshi Kagaku Co., Ltd.
This is the result of measurement with a load of 300 gf added.

Here, the elastic layer 24 is formed on the pad member 4.
By providing, the contact surface of the pad sheet 25 that contacts the inner surface of the endless belt 3 (however, the powder 101 is interposed) can be aligned with the outer peripheral surface of the heat fixing roll 2. That is, when the pad member 4 is pressed toward the heat fixing roll 2 with a load of a certain level or more, the elastic layer 24 is deformed and the contact surface of the pad sheet 25 is pressed against the outer peripheral surface of the heat fixing roll 2. It is designed to transform like this. Therefore, when the pad member 4 is pressed against the heating and fixing roll 2 by a compression coil spring (not shown), the endless belt 3 is pressed against the heating and fixing roll 2 without a gap.

The pad member 4 usually has a center line average roughness Ra ₇₅ of about 2.0 to 4.0 μm on the surface thereof. Particularly when the pad member 4 having a rough surface is used, It is possible to uniformly avoid the direct contact of the body 101 with the inner surface of the endless belt 4 by uniformly entering the concave portion on the surface of the pad member 4, and effectively and stably reduce the frictional resistance for a long period of time. Further, when the pad member 4 having a rough surface is used, a very high abnormal noise is often generated. However, by interposing the powder 101, the generation of such abnormal noise can be suppressed. The center line average roughness Ra of the surface of the pad member 4 that achieves such an effect more effectively
_As the relationship between ₇₅ and the size of the powder 101, specifically, the center line average roughness Ra _{75 of the} surface of the pad member 4 is 0.1 to 5.0.
μm (preferably 2.0 to 4.0 μm, more preferably 2.5 to 3.5 μm), and the size of the powder 101 is 0.1 to 10 μm (preferably 0.5 to 2. 0
μm) is preferred.

Even if the pad member 4 having a high coefficient of dynamic friction is used, the powder 101 is used for the endless belt 3
By interposing it between the pad member 4 and the pad member 4, the frictional resistance between the endless belt 3 and the pad member 4 can be reduced, and can be maintained for a long period of time. Further, when the pad member 4 whose surface has a very high dynamic friction coefficient is used, a very large abnormal noise is often generated, but such an abnormal noise can also be suppressed.

The surface of the pad member 4 indicates the contact surface with the endless belt 3 (however, the powder 101 is interposed),
In the case of the fixing device 1, it indicates the surface of the sheet member 25.

The heat fixing roll will be described. The heat fixing roll 2 is rotatably driven by a driving source (not shown) along the arrow direction at a predetermined speed, for example, a peripheral speed of 260 mm / sec. The heat fixing roll 2
Is, for example, an outer diameter of 62 mm, an inner diameter of 55 mm, and a length of 350
It is provided with a metal core 5 formed in a cylindrical shape of mm,
As the metal core 5, for example, one made of aluminum, stainless steel or the like is used. The surface of the metal core 5 is covered with HTV silicone rubber (rubber hardness of JIS-A 45 degrees) as the elastic layer 6 to a thickness of 2 mm, and the surface of the elastic layer 6 is Further, as the top coat layer 7, fluororubber is coated with a thickness of 50 μm, and the surface of the top coat layer 7 is finished in a state close to a mirror surface. The rubber hardness of the elastic underlayer 6 is measured by a spring type A hardness meter manufactured by Teclock Co., Ltd. according to JIS K630.
Based on 1, the value is the result of measurement with a load of 1,000 gf added. The metal core 5 may be made of a metal having a high thermal conductivity other than aluminum or stainless steel, and the top coat layer 7 may be any other elastic body having a high heat resistance. Materials can be used.

A halogen lamp 8 having an output of 1000 W is arranged inside the metal core 5 as a heating source, and the heating and fixing roll 2 is heated from the inside by the halogen lamp 8 so that the surface temperature becomes a predetermined temperature. It is supposed to be done. The surface temperature of the heat fixing roll 2 is detected by the temperature sensor 9 which contacts the surface of the heat fixing roll 2, and the surface temperature of the heat fixing roll 2 is, for example, 1
The temperature is controlled to 75 ° C. by a temperature controller (not shown).

On the surface of the heat-fixing roll 2, an amine-modified silicone oil having a viscosity of about 300 cs, for example, is uniformly supplied as a release agent by the release agent supply device 10. In the release agent supply device 10, the release agent 12 dropped from the oil pipe 11a is supplied to the pickup roll 11c via the oil wick 11b, and the excess release agent 12 supplied to the pickup roll 11c is removed. ,
Oil pan 1 scraped by the metering blade 11d
It is returned from 1e to an oil tank (not shown). The release agent 12 supplied to the surface of the pickup roll 11c is heated by the donor roll 11f to the heat fixing roll 2
It is designed to be applied to the surface of. It should be noted that the cleaning blade 11g removes adhered substances from the surface of the pickup roll 11c. An external heating roll 1 for heating the surface of the heat fixing roll 2 from the outside at a predetermined timing is provided on the surface of the heat fixing roll 2.
3 is provided.

The fixing device of the present invention is not particularly limited as long as it is a roll belt type fixing device as shown in FIG. 1, and is suitably applied to, for example, an electromagnetic induction heating type fixing device. be able to.

[0034]

EXAMPLES The present invention will be described more specifically below with reference to examples. However, each of these examples does not limit the present invention.

(Embodiment 1) After the pad member 4 is mounted on the fixing device 1 shown in FIG. 1, an appropriate amount of PTFE spherical particles is sprinkled on its surface (sheet surface) with gauze to give an appropriate amount of viscosity 3.
00cs amino-modified silicone oil (Shin-Etsu Chemical)
Was lubricated, and the endless belt 3 was attached. Further, in the fixing device 1, as the device for evaluating the endless belt 3 and the pad member 4 in the fixing device, only the heating fixing roll 2 and the endless belt 3 are heated and rotated, and the belt nip load, the number of rotations of the heating fixing roll, Prepare a free-running bench that can change the temperature of the heating and fixing roll 2 arbitrarily,
I put it on. Using such a fixing device, evaluation was performed as follows. The following materials were used as the endless belt 3, the pad member 4, and the powder 101.

-Evaluation-The belt nip load of the idle bench was set to 34 kgf, the number of revolutions of the heat fixing roll 2 was set to 74.4 rpm, the temperature of the heat fixing roll 2 was set to 175 ° C, and the heat fixing roll 2 was rotated. The measurement was carried out using the load torque to the bench motor and the noise level of the belt nip portion, and idling was continuously performed for 40 hours. The load torque measurement value is a value converted from the current flowing into the motor, and the noise level measurement is performed by placing a sound collecting microphone 30 mm away from the belt nip, and using an integral average precision noise meter (NL-made NL- 14), and the measurement was performed every 4 hours. The results are shown in Table 1.

—Endless Belt (Belt Member) 3— The endless belt 3 was manufactured as follows. N-methylpyrrolidone solution of polyimide precursor (trade name: U
Varnish S, Ube Industries, Ltd., solid content concentration 18%, viscosity was about 5 Pa · s) was used as the coating liquid. As core, outer diameter 30m
An aluminum cylinder with a length of m and a length of 500 mm is prepared, and 0.8 to 1 μmRa (JIS
Blasting (-94 calculation standard) was performed. Furthermore, a silicone-based release agent (trade name: KS70) is formed on the outer peripheral surface of the core body.
0, manufactured by Shin-Etsu Chemical Co., Ltd., and baked at 300 ° C. for 30 minutes.

A float 4 having a circular hole 48 as shown in FIG.
7 is floated on the polyimide precursor coating liquid 49, and then the core 4
1 was immersed in and pulled up from the coating liquid 48 through the circular hole 48, and the coating liquid 49 was applied to the surface of the core body 41 to form a polyimide precursor coating film 50. The coating film 50 was dried at 90 ° C. for 90 minutes to semi-cure the coating film. Then, a PFA dispersion liquid in which 2 parts by weight of carbon was dispersed was applied onto the semi-cured film, dried at 60 ° C. for 15 minutes, and further 380 ° C. 20
It was heated and baked for a minute. The film is removed from the core, and P is applied to the outer peripheral surface.
An endless belt coated with FA was produced. The polyimide base material average film thickness of this endless belt is 80 μm, the PFA average film thickness is 30 μm, and the inner surface roughness of the belt is center line average roughness R.
It was 0.6 μm at a ₇₅ . The coefficient of dynamic friction is 0.
It was 10. This endless belt was cut into a width of 330 mm to prepare an endless belt 3.

—Pad Member 4-— As the pad member 4, polytetrafluoroethylene (P
Glass fiber sheet impregnated with TFE (sheet member 2
The one covered by 5) (made by Chukoh Kasei) was prepared. The center line average roughness Ra ₇₅ of the surface of the pad member 4 (sheet surface) was 3.1 μm.

—Powder 101— As the powder 101, PTFE spherical particles having an average particle diameter of 2 μm (manufactured by Daikin Industries, Lubron L-2) were prepared. The spheroidization rate of the particles was about 90%.

(Comparative Example 1) The powder 1 is applied to the surface of the pad member 4.
Evaluation was performed in the same manner as in the example except that 01 was not applied. The results are shown in Table 1.

[0042]

[Table 1]

From Table 1, particles can be obtained by interposing PTFE spherical particles (powder) between the endless belt (endless belt (belt member): endless belt having a particularly rough inner surface) and the pad member (pressure applying member). It can be seen that the load torque is lower and the generation of noise is suppressed as compared with the case where no interposition is provided. This indicates that the friction between the endless belt and the pressure applying member is reduced due to the presence of the spherical particles. Further, it can be seen that the particles act continuously and the load torque and noise are stable for a long time.

[0044]

As described above, according to the present invention, it is possible to provide a fixing device in which the frictional resistance between a pressure applying member and a belt member (particularly, a belt member having a rough inner surface) is reduced and which is maintained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a fixing device of the present invention.

FIG. 2 is a schematic configuration diagram showing the vicinity of a belt nip portion of the fixing device of the present invention.

FIG. 3 is a schematic configuration diagram illustrating a step of applying a polyimide precursor solution to a core body.

[Explanation of symbols]

2 Heat fixing roll (roll member) 3 Endless belt (belt member) 4 Pad member (pressure applying member) 101 powder

Claims (7)

[Claims] 1. A roll member, a belt member that rotates while traveling in contact with the roll member, a heating source that heats at least one of the roll member and the belt member, and a non-rotating state inside the belt member. A fixing device comprising: a pressure applying member that is disposed and presses the belt member against the roll member; and a powder that is interposed between the belt member and the pressure applying member. 2. The fixing device according to claim 1, wherein the powder is spherical particles. 3. The fixing device according to claim 1, wherein the powder is polytetrafluoroethylene (PTFE) particles. 4. The powder has a mean particle size of 0.1 to 0.1.
The fixing device according to claim 1, wherein the fixing device has a thickness of 10 μm. 5. The fixing device according to claim 1, wherein the base material of the belt member is a polyimide resin. 6. The center line average roughness Ra ₇₅ of the inner surface of the belt member is 0.1 to 5.0 μm, and the size of the powder is 0.1 to 10 μm in average particle size. The fixing device according to claim 1, wherein the fixing device is a fixing device. 7. The center line average roughness Ra ₇₅ of the surface of the pressure applying member is 0.1 to 5.0 μm, and the size of the powder is 0.1 to 10 μm in average particle size. The fixing device according to any one of claims 1 to 6, wherein: