JP2024003341A - Electro-photographic belt, fixing device, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electro-photographic belt and a fixing belt the metal layers of which are hardly separable and the inner layers are hardly shaved, even when having been stored in a hot and humid environment.

SOLUTION: An electro-photographic belt comprises an endless shaped base that includes at least one of polyimide and polyamide imide, a metal layer that is provided on the outer circumferential face of the base, and a surface layer that is provided on the outer circumferential face of the metal layer, and further includes an inner surface layer that is provided in contact with the inner circumferential face of the base, the water vapor permeation of the inner surface layer being 10 g/(m² day) or less.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present disclosure relates to an electrophotographic belt, a fixing device, and an image forming apparatus used in an electrophotographic image forming apparatus such as a copying machine and a printer.

Generally, in a thermal fixing device (hereinafter also simply referred to as a "fixing device") used in an image forming apparatus, a rotating body serving as a fixing member, such as a pair of heated rollers and a roller, or a belt and a roller, is pressed into contact with each other. . Then, a recording medium holding an image of unfixed toner is introduced into a pressure contact area formed between the rotating bodies and heated, melting the toner and fixing the image on the recording medium.

The members for the fixing device include a fixing member, a pressure member, and the like. The rotating body with which the unfixed toner image held on the recording medium comes into contact is called a fixing member, and depending on its form, it is called a fixing roller, a fixing belt, etc. On the other hand, a rotating body that is not in contact with the unfixed toner image and is located on the opposite side of the recording medium is called a pressure member, and depending on its form, it is called a pressure roller, a pressure belt, or the like.

Patent Document 1 discloses that when a fixing belt having a circular polyimide resin base layer and a metal layer provided on the outer peripheral surface of the fixing belt is stored in a high temperature and high humidity environment, the polyimide resin base layer and the metal layer peel off. Discloses technology to prevent this. Furthermore, Patent Document 2 describes a fixing belt used in an electromagnetic induction heating type fixing device that has an annular resin base layer and a metal layer provided on the outer peripheral surface of the resin base layer in a high temperature and high humidity environment. Discloses a technique for suppressing peeling between a resin base layer and a metal layer when a toner image is repeatedly fixed thereon after long-term storage. Patent Document 1 and Patent Document 2 disclose that the problem of peeling between the resin base material layer and the metal layer is caused by moisture at the interface between the resin base material layer and the metal layer.

In order to solve the above problem, Patent Document 1 lowers the imidization rate of the outer circumferential surface of the polyimide resin base layer than the central part in the thickness direction, so that the plating solution and the outer circumferential surface of the polyimide resin base layer are It is described that the wettability becomes high and the adhesiveness between the polyimide resin base layer and the metal layer becomes high even under high temperature and high humidity conditions (paragraph [0019]).
In addition, Patent Document 2 addresses the above problem by suppressing the water absorption rate of the resin base layer to 3% or less, so that even if the fixing belt is stored in a high temperature and high humidity environment, the resin base layer and the metal layer will not overlap. It is stated that peeling between the resin base layer and the metal layer can be suppressed by reducing the amount of water present at the interface (paragraphs [0021]-[0022]).

JP 2021-71678 Publication Japanese Patent Application Publication No. 2021-71679

Patent Document 1 and Patent Document 2 disclose countermeasures against intruding moisture, but do not disclose countermeasures for preventing the intrusion of the moisture that causes the intrusion.
In the case of a fixing belt that uses a base material (polyimide resin) that has a new function mixed with filler, it may not be possible to suppress water absorption by controlling the imidization rate of the polyimide resin. .
One aspect of the present disclosure is directed to providing an electrophotographic belt and a fixing belt in which a metal layer is not easily peeled off from a base material and an inner layer is not easily scraped even after being stored in a high temperature and high humidity environment. be.
Further, another aspect of the present disclosure is directed to providing a fixing device that contributes to the formation of high-quality electrophotographic images. Furthermore, another aspect of the present disclosure is directed to providing an image forming apparatus that can form high-quality electrophotographic images.

According to one aspect of the present disclosure,
an endless-shaped base material containing at least one of polyimide and polyamideimide;
a metal layer provided on the outer peripheral surface of the base material;
An electrophotographic belt comprising a surface layer provided on the outer peripheral surface of the metal layer,
further comprising an inner surface layer provided in contact with the inner peripheral surface of the base material,
An electrophotographic belt is provided in which the inner layer has a water vapor permeability of 10 g/(m ² ·day) or less.

According to another aspect of the present disclosure, there is provided the above-described fixing belt for electrophotography, in which the inner layer has a thickness of 10 μm or more and 20 μm or less.
According to another aspect of the present disclosure, a fixing device including the above-described fixing belt is provided.
Furthermore, according to another aspect of the present disclosure, a photoreceptor, a charging device that charges the photoreceptor, an exposure device that exposes the charged photoreceptor to form an electrostatic latent image, and a An image forming apparatus comprising: a developing device that develops the electrostatic latent image formed on the photoreceptor with toner to form a toner image; a transfer device that transfers the toner image formed on the photoreceptor to a recording medium; and the fixing device. The fixing device is a fixing device that heats an unfixed toner image on a recording medium with a fixing belt and fixes it onto the recording medium, and the fixing belt is the fixing belt described above. Equipment is provided.

The cause of peeling between the base material and the metal layer is that moisture in the atmosphere passes through the base material and reaches the interface between the base material and the metal layer. According to one aspect of the present disclosure, there are provided an electrophotographic belt and a fixing belt in which a metal layer is not easily peeled off from a base material and an inner layer is not easily scraped even when used for a long period of time in a high temperature and high humidity environment. Further, according to another aspect of the present disclosure, there are provided a fixing device and an image forming apparatus that can form high-quality electrophotographic images and have excellent paper passing durability.

1 is a schematic diagram of an image forming apparatus in an example. FIG. 2 is a schematic diagram of a fixing device in an example. FIG. 3 is a schematic diagram of a fixing film in an example.

Hereinafter, an electrophotographic belt having an endless belt shape according to at least one embodiment of the present disclosure will be described in detail. Note that the technical scope of the present disclosure is not limited to the following explanation.
The electrophotographic belt is used as a fixing belt in the image forming apparatus shown in FIG. 1, for example. FIG. 1 is a cross-sectional view of a color electrophotographic printer that is an example of an image forming apparatus according to the present embodiment, and is a cross-sectional view taken along the sheet conveyance direction. In this embodiment, the color electrophotographic printer is simply referred to as a "printer."

The printer shown in FIG. 1 includes image forming sections 10 for each color of Y (yellow), M (magenta), C (cyan), and Bk (black). The photosensitive drum (photosensitive body) 11 is charged in advance by a charger 12 . Thereafter, the photosensitive drum 11 is exposed to light by a laser scanner 13 to form an electrostatic latent image. The electrostatic latent image is turned into a toner image by the developing device 14. The toner images on the photosensitive drum 11 are sequentially transferred by a primary transfer blade 17 to an image carrier, for example, an intermediate transfer belt 31 . After the transfer, the toner remaining on the photosensitive drum 11 is removed by a cleaner 15. As a result, the surface of the photosensitive drum 11 becomes clean and ready for the next image formation.

On the other hand, the recording materials P are fed out one by one from the paper feed cassette 20 or the multi-sheet feed tray 25 and fed into the pair of registration rollers 23 . The registration roller pair 23 once receives the recording material P, and if the sheet is skewed, straightens it. Then, the registration roller pair 23 feeds the recording material P between the intermediate transfer belt 31 and the secondary transfer roller 35 in synchronization with the toner image on the intermediate transfer belt 31 . The color toner image on the intermediate transfer belt is transferred onto the recording material P by a transfer body, for example, a secondary transfer roller 35. Thereafter, the toner image on the sheet is fixed to the sheet by applying heat and pressure to the sheet by the fixing device 40.

Next, the fixing device 40 used in this embodiment will be explained.
The fixing device 40 is an electromagnetic induction type fixing device including the fixing belt according to the embodiment described above.
As shown in FIG. 2, a pressure roller (pressure member) 44 is arranged to press a part of the endless fixing belt 41, and from the viewpoint of efficient fixing, the fixing belt 41 and the pressure roller 44 are A fixing nip portion N is formed therebetween.

A facing member 43 is arranged inside the fixing belt 41 at a position facing the pressure roller 44 . The opposing member 43 is made of metal, heat-resistant resin, heat-resistant rubber, etc., and includes a pad 43b that contacts the inner peripheral surface of the fixing belt 41 to locally increase pressure, and a support 43a that supports the pad 43b. . An electromagnetic induction heating device 42 having a built-in electromagnetic induction coil (excitation coil) 42a is provided at a position facing the pressure roller 44 with the fixing belt 41 at the center.
The electromagnetic induction heating device (electromagnetic induction device) 42 applies an alternating current to an electromagnetic induction coil, changes the generated magnetic field with an excitation circuit, and generates an eddy current in a metal layer within the fixing belt 41 . This eddy current is converted into heat (Joule heat) by the electrical resistance of the metal layer, and as a result, the surface of the fixing belt 41 generates heat.

Note that the position of the electromagnetic induction heating device 42 is not limited to the position shown in FIG. It may be installed inside.
The pressure roller 44 is rotationally driven in a rotational direction 45 at a predetermined rotational circumferential speed by a driving means (not shown). This rotational drive of the pressure roller 44 causes a rotational force to act on the cylindrical fixation film 41 due to the pressure friction force between the pressure roller 44 and the fixing film 41 at the fixing nip portion N. Then, the fixing film 41 slides in close contact with the downward facing surface of the pad 43b and enters a driven rotation state in the same direction as the rotation direction 45. The facing member 43 also serves as a rotation guide member for the cylindrical fixing film 41.

The pressure roller 44 is rotationally driven, and the cylindrical fixing film 41 is brought into a driven rotation state, and the surface of the fixing belt 41 is rapidly heated by the electromagnetic induction heating device 42 to reach a predetermined temperature. It will be in a controlled state. In this state, the recording material P carrying the unfixed toner image T is introduced between the fixing film 41 and the pressure roller 44 in the fixing nip N. Then, at the fixing nip N, the toner image bearing side surface of the recording material P comes into close contact with the outer surface of the fixing film 41, and the recording material P is conveyed through the fixing nip T together with the fixing film 41. During this nipping and conveying process, the recording material P is heated by the heat of the fixing film 41 generated by the above-mentioned eddy current, and the unfixed toner image T on the recording material P is heated and pressurized onto the recording material P to be melted and fixed. be done. The recording material P that has passed through the fixing nip portion N is separated by curvature from the outer surface of the fixing film 41 and is discharged and conveyed.

Next, the fixing belt will be described in detail.
As shown in FIG. 3, the fixing belt 41 of the present disclosure has an inner surface layer 41a on the innermost peripheral surface, a base material (base layer) 41b, a metal layer 41c, an elastic layer 41d, and a surface layer 41e in this order. Note that in order to increase the adhesiveness between the metal layer 41c and the elastic layer 41d, and between the elastic layer 41d and the surface layer 41e, an adhesive layer (not shown) may be used to bond them.

(1) Inner layer 41a
The material of the inner layer 41a must be as impervious to moisture as possible, and must have heat resistance because the fixing belt 41 generates heat due to electromagnetic induction.
As a means of evaluating whether water permeates or not, JIS specifies a method for determining the water vapor permeability of plastic films and sheets (JIS K-7129-1) as follows.

WVTRs (g/( ^m2・day))=WVTRstd×TR/TS×AR/AS
WVTRs: water vapor permeability of test piece g/( ^m2・day)
WVTRstd: Water vapor permeability of standard test piece g/( ^m2・day)
TR: Time (s) required for the relative humidity in the low humidity chamber to increase from the initial level to the final level for the standard specimen.
TS: Time (s) required for the relative humidity in the low humidity chamber to increase from the initial level to the final level for the specimen.
AR: Transmission area of standard test piece (m ² )
AS: Transmission area of test piece (m ² )
Here, the standard test piece refers to a sample whose water vapor permeability is known.

Further, although there is no description regarding thickness in JIS K-7129-1, since thickness affects water vapor permeability, it is preferable to measure at the thickness actually used.
A heat-resistant resin or metal is used as a material having a water vapor permeability of 10 g/(m ² ·day) or less and having heat resistance.
Further, in order to improve adhesiveness with the base material 41b, the inner surface of the base material 41b may be coated with a primer or an adhesive (not shown).

As the heat-resistant resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polyetheretherketone resin (PEEK), polyvinylidene chloride resin, high-density polyethylene resin (high-density PE), etc. are used. Among these, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) is particularly preferred.
As the metal, stainless steel is preferred because it has excellent strength, flexibility, and rust resistance, and does not generate heat due to eddy current during IH fixing.
Further, from the viewpoint of strength, flexibility, and heat capacity, the thickness is preferably 10 μm or more and 20 μm or less.

(2) Base material 41b
The material of the base layer 41b includes at least one of polyimide and polyamideimide from the viewpoint of excellent heat resistance, strength, flexibility, and heat capacity. In particular, it is preferable to include at least one of an aromatic polyimide resin and a polyamideimide resin. Further, the thickness of the base material is not particularly limited, but from the viewpoint of ensuring flexibility of the electrophotographic belt, it is preferably, for example, 20 μm or more and 100 μm or less.
The outer surface of the base material 41b may be subjected to surface treatment in order to provide adhesiveness with the metal layer 41c. For surface treatment, it is possible to use one or a combination of physical treatments such as blasting, lapping, and polishing, and chemical treatments such as oxidation, coupling agent treatment, and primer treatment. .

(3) Metal layer 41c
The metal layer 41c is a heat generating layer that has a function of generating heat by eddy current generated within this layer when a magnetic field is applied, and is made of a metal that produces an electromagnetic induction effect. Examples of metals that produce electromagnetic induction include single metals such as nickel, iron, copper, gold, silver, aluminum, chromium, tin, and zinc, or alloys containing two or more metals. Considering cost, heat generation performance, and workability, copper, nickel, aluminum, iron, and chromium are suitable, and among these, copper or an alloy containing copper as a main component is particularly preferable.

The optimal thickness of the metal layer 41c varies depending on the material of the metal. For example, when copper is used for the metal layer 41c, from the viewpoint of efficiently generating heat, the thickness of the metal layer 41c is preferably 3 μm or more and 50 μm or less, more preferably 3 μm or more and 30 μm or less, and 5 μm or more and 20 μm or less. It is more preferable that it is the following.
Further, as a method for forming the metal layer 41c, an electrolytic plating method is preferable, but when using the base material 41b made of resin, it is difficult to perform electrolytic plating directly, so a base material is applied to the outer peripheral surface of the base material layer 41b. It is necessary to form a metal layer (not shown).

Furthermore, in order to improve the film strength of the metal layer 41c, suppress cracks due to repeated deformation, oxidation deterioration due to long-term repeated heating, etc., and maintain heat generation characteristics, a metal protective layer (unprotected) in contact with the metal layer 41c is added. ) may also be provided. Specifically, it is often composed of copper or nickel, and in particular, oxidation-resistant metal nickel ( or nickel alloy).

(4) Elastic layer 41d
The material of the elastic layer is not particularly limited, and any known material used as an elastic layer of a fixing member such as a fixing rotating body can be used. It is preferable that the elastic layer contains silicone rubber which has excellent heat resistance. Furthermore, addition-curing liquid silicone rubber is preferably used as a raw material for silicone rubber.
The thickness of the elastic layer can be appropriately designed in consideration of the surface hardness of the fixing belt 41 and the width of the fixing nip to be formed. The thickness of the elastic layer is preferably 100 μm or more and 500 μm or less, more preferably 200 μm or more and 400 μm or less. By setting the thickness of the elastic layer within this range, a sufficient width of the fixing nip portion can be ensured when the fixing belt 41 is incorporated into a fixing device.

The elastic layer may contain filler. Fillers are added to control thermal conductivity, heat resistance, and elastic modulus.
Specifically, the following can be mentioned. Silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), silica (SiO ₂ ), boron nitride (BN), aluminum nitride (AlN), alumina (Al ₂ O ₃ ), iron oxide (Fe ₂ O ₃ ), Zinc oxide (ZnO), magnesium oxide (MgO), titanium oxide (TiO ₂ ), copper (Cu), aluminum (Al), silver (Ag), iron (Fe), nickel (Ni), carbon black (C), Carbon fiber (C), carbon nanotube (C), etc.
Furthermore, a reaction control agent called an inhibitor may be added to the material constituting the elastic layer to control the reaction start time. As the reaction control agent, known substances such as methylvinyltetrasiloxane, acetylene alcohols, siloxane-modified acetylene alcohols, and hydroperoxides are used.

(5) Surface layer 41e
The surface layer 41e includes a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) and perfluoropolyether (PFPE). A fluororesin material having a thickness of 100 μm or less, preferably 10 to 70 μm can be used. Examples of the fluororesin material include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), and PFA.

Next, a method for manufacturing the fixing member used in this example will be described. In this example, a fixing belt as shown in FIG. 3 was manufactured using a manufacturing method consisting of steps 1 to 7 below.

(Step 1)
A stainless steel mold with an inner diameter of 25 mm and a width of 400 mm was prepared. After applying a polyimide precursor paint (trade name: UPIA-AT, UBE Corporation) to the mold, it was baked at 390° C. for 60 minutes. By peeling off the polyimide film from the surface of the stainless steel mold, an endless belt-shaped polyimide resin base material having an inner diameter of 25 mm, a film thickness of 60 μm, and a length of 390 mm was obtained.

(Step 2)
After applying a liquid silicone rubber primer to the inner surface of the polyimide resin base material, dry it. After drying, apply an addition-curing silicone rubber adhesive (product name: SE1819CV, a mixture of equal amounts of "Liquid A" and "Liquid B" manufactured by Dow Corning Toray) to a substantially uniform thickness of approximately 20 μm. It was applied to. Cover the inner surface of the base material with a fluororesin tube (PFA, 5 μm thick, melting point 306°C, product name: NSE, Gunze Corporation) whose outer surface has been hydrophilized by laser etching, and evenly handle the belt surface from above the fluororesin tube. As a result, excess adhesive was removed from between the polyimide resin base material and the fluororesin tube. Then, it was placed in an electric furnace set at a temperature of 200° C. for 10 minutes to be cured. As a result, a polyimide resin base material having a PFA inner layer was obtained.

(Step 3)
The outer peripheral surface of the polyimide resin base material has been blasted (specifically, sandblasting using alumina abrasive grains, cutting, sandpapering, etc.) and then soaked in a sodium hydroxide aqueous solution adjusted to pH 11 at a temperature of 5°C for 50 minutes. Soaked for minutes.

(Step 4)
An electroless nickel plating layer with a film thickness of 0.3 μm as a base metal layer, a 10 μm electrolytic copper plating layer as a metal heat generating layer, and a 10 μm nickel layer as a metal protective layer were sequentially formed on the outer peripheral surface of the polyimide resin base material. .

(Step 5)
As a raw material for forming the elastic layer, an addition-curing liquid silicone rubber (trade name: DY35-1355, manufactured by Dow Corning Toray Industries, Inc.) containing a filler was prepared. After coating the outer circumferential surface of the base material using a ring coating method, the addition-curing silicone rubber composition layer is crosslinked by heating at 200°C for 1 hour to form an elastic layer with a thickness of 300 μm. did.

(Step 6)
While rotating the base material on which the elastic layer was formed at a moving speed of 20 mm/sec in the circumferential direction, an ultraviolet lamp placed at a distance of 10 mm from the surface of the elastic layer was used to apply air to the surface of the elastic layer. Ultraviolet rays were irradiated in an atmosphere. A low-pressure mercury ultraviolet lamp (trade name: GLQ500US/11, manufactured by Toshiba Lighting & Technology Co., Ltd.) was used as the ultraviolet lamp, and irradiation was performed so that the cumulative amount of light at a wavelength of 185 nm on the irradiated surface was 800 mJ/cm ² .
Next, an addition-curing silicone rubber adhesive (trade name: SE1819CV, a mixture of equal amounts of "Liquid A" and "Liquid B" manufactured by Dow Corning Toray Industries, Inc.) is applied to the surface of the elastic layer to a thickness of approximately 20 μm. It was applied almost uniformly.

(Step 7)
Cover the belt with a fluororesin tube (PFA-1, 20 μm thick, melting point 306°C, product name: NSE, Gunze Co., Ltd.) whose inner surface has been hydrophilized by laser etching, and evenly treat the belt surface from above the fluororesin tube. The excess adhesive was removed from between the elastic layer and the fluororesin tube.
Then, the elastic layer and the base layer coated with the surface layer were placed in an electric furnace set at a temperature of 200°C, and heated for 1 hour to harden the adhesive and bond the fluororesin tube onto the elastic layer. Both ends were cut to obtain a fixing belt with a width of 350 mm.

[Example 2]
A fixing belt was obtained in the same manner as in Example 1, except that in Step 2 of Example 1, a 10 μm thick fluororesin tube whose outer surface was subjected to hydrophilic treatment was used.

[Example 3]
A fixing belt was obtained in the same manner as in Example 1, except that in Step 2 of Example 1, a fluororesin tube with a thickness of 20 μm whose outer surface was subjected to hydrophilic treatment was used.

[Example 4]
A fixing belt was obtained in the same manner as in Example 1, except that in Step 2 of Example 1, a fluororesin tube having a thickness of 50 μm and having a hydrophilic outer surface was used.

[Example 5]
By the method described below, a polyimide resin base material having a stainless steel (SUS) cylindrical body (metal inner layer) instead of the PFA inner layer as an inner layer that can withstand the firing temperature of polyimide was obtained.

(Step 1)
A stainless steel cylindrical body with an inner diameter of 25 mm, a width of 390 mm, and a thickness of 20 μm was prepared. A stainless steel mold with an outer diameter of 25 mm and a width of 450 mm was fitted inside this cylindrical body, a polyimide precursor paint was applied to the surface of this cylindrical body to form a film, and the film was baked at a temperature of 390° C. for 60 minutes. By removing the stainless steel mold from the stainless steel cylindrical body, a polyimide resin base material having an endless belt-shaped metal inner layer was obtained. The sizes of the polyimide resin base material having the metal inner layer are as follows.
The inner diameter is 25 mm, the film thickness (total of the thickness of the polyimide resin base material and the metal inner layer) is 60 μm, and the length is 390 mm.
Thereafter, a fixing belt was obtained in the same manner as in Step 3 and subsequent steps of Example 1.

[Example 6]
Except that in Step 2 of Example 1, a polyether ether ketone resin tube (PEEK, seamless belt, Gunze Co., Ltd., thickness 10 μm) with a hydrophilic outer surface was used instead of a fluororesin tube with a hydrophilic outer surface. A fixing belt was obtained in the same manner as in Example 1.

[Example 7]
Same as Example 1 except that in step 2 of Example 1, a high-density polyethylene resin tube (Ube Film Co., Ltd., thickness 10 μm) with a hydrophilic outer surface was used instead of a fluororesin tube with a hydrophilic outer surface. A fixing belt was obtained.

[Comparative example 1]
A fixing belt was obtained in the same manner as in Example 1 except that Step 2 was not performed.

[Comparative example 2]
In Step 2 of Example 1, a polyether sulfone resin tube (PES, Sumika Excel, Sumitomo Chemical Co., Ltd., 20 μm thick) whose outer surface was treated with hydrophilic treatment was used instead of the fluororesin tube (PFA, 10 μm thick). A fixing belt was obtained in the same manner as in Example 1 except for this.

(Water vapor transmission rate measurement method)
The water vapor permeability of each fixing belt was measured according to the method described above.
For each sample for measurement, the water vapor permeability of the base material was measured by cutting the base material at the step 1 of Example 1, the PFA inner layer by cutting the fixing belt at the step 2 of Example 1, and the metal inner layer by cutting the base material at the step 2 of Example 1. The belt from Step 1 of Example 2 was cut and measured. The cut size was a square with each side of 7 cm.

The following were used as standard test pieces.
Known sample: Polystyrene film Water vapor permeability: 30g/( ^m2・day)
Thickness: 25μm
Furthermore, when measuring water vapor permeability for comparison of sheet functions, in the present disclosure, the comparison is made while the thicknesses of the base material and the inner layer are different. This is because peeling between the base material and the metal layer affects the amount of moisture that has reached between the base material and the metal layer, so if the thicknesses are aligned and measured, accurate evaluation will not be possible.

(Image formation evaluation)
The fixing belt of each example was stored for 96 hours under an environment of a temperature of 95° C. and a relative humidity of 100%. The stored fixing belt was attached to the fixing device of the image forming apparatus described above. The outer circumferential temperature of the fixing belt in the area in contact with the recording material was controlled to be 130°C.
Using this image forming apparatus, image formation was evaluated using GF-C081 (manufactured by Nippon Paper Industries, Ltd.) as an A4 paper recording material.

<Image formation evaluation 1>
In image formation evaluation 1, 10 halftone images with an image density of 50% were output. Visual observation was made for the presence or absence of poor image quality or paper wrinkles in the output images, and for the presence or absence of peeling at the interface between the base material layer and the metal layer of the fixing belt.
The judgment criteria were as follows.
A: When none of peeling at the interface, poor image quality, and paper wrinkles occur B: When one or more of peeling at the interface, poor image quality, and paper wrinkles occur

<Image formation evaluation 2>
In image formation evaluation 2, the lifespan of the inner layer was evaluated.
Evaluation was made as follows according to the number of prints in which the inner layer was scraped and the base material was exposed.
A: When the number of prints was 700,000 or more, the inner layer was scraped and the base material was exposed.
B: The number of prints was 500,000 or more and less than 700,000, and the inner layer was scraped and the base material was exposed.
C: The number of prints was less than 500,000, and the inner layer was scraped and the base material was exposed.

<Image formation evaluation 3>
In image formation evaluation 3, the time from when the power is turned on until the surface of the fixing belt reaches 160°C is defined as the "rise time", and the rise time is compared to the time when a fixing belt made by the conventional method (Comparative Example 1) is used. The results were compared and evaluated as follows.
A: When the rise time is within +5 seconds B: When the rise time is over +5 seconds but within +10 seconds Table 1 shows the evaluation results of the present example and comparative example.

From the above results, it can be seen that the fixing belt of this example suppresses peeling at the interface, suppresses the occurrence of poor image quality or paper wrinkles, and suppresses other adverse effects compared to the fixing belt of the comparative example. .

10: Image forming section 11: Photosensitive drum (photosensitive member)
12: Charger (charging device)
13: Laser scanner (exposure device)
14: Developing device (developing device)
15: Cleaner 17: Primary transfer blade 20: Paper feed cassette 25: Multi-sheet feed tray 23: Registration roller pair 31: Intermediate transfer belt 35: Secondary transfer roller 40: Fuser (fixing device)
41: Fixing belt 41a: Inner layer 41b: Base material 41c: Metal layer 41d: Elastic layer 41e: Surface layer 42: Electromagnetic induction heating device 42a: Electromagnetic induction coil 43: Opposing member 43a: Support 43b: Pad 44: Pressure Roller 45: Fixing belt/pressure roller Rotation direction N: Fixing nip P: Recording material T: Toner

Claims (6)

an endless-shaped base material containing at least one of polyimide and polyamideimide;
a metal layer provided on the outer peripheral surface of the base material;
An electrophotographic belt comprising a surface layer provided on the outer peripheral surface of the metal layer,
further comprising an inner surface layer provided in contact with the inner peripheral surface of the base material,
An electrophotographic belt, characterized in that the inner layer has a water vapor permeability of 10 g/(m ² ·day) or less. The electrophotographic belt according to claim 1, wherein the inner layer has a thickness of 10 μm or more and 20 μm or less. The electrophotographic belt according to claim 1, wherein the inner layer includes at least one selected from the group consisting of PFA, PEEK, and high-density PE. The electrophotographic belt according to claim 1, wherein the electrophotographic belt is a fixing belt. A fixing device that brings an unfixed toner image on a recording medium into contact with a fixing belt, heats the unfixed toner image with the fixing belt, and fixes the unfixed toner image on the recording medium,
A fixing device, wherein the fixing belt is an electrophotographic belt according to any one of claims 1 to 4. a photoreceptor;
a charging device that charges the photoreceptor;
an exposure device that exposes a charged photoreceptor to form an electrostatic latent image;
a developing device that develops the electrostatic latent image formed on the photoreceptor with toner to form a toner image;
a transfer device that transfers the toner image formed on the photoreceptor to a recording medium;
A fixing device according to claim 5;
An image forming apparatus comprising:

Images