JP3032726B2 - Fixing part film and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic copying machine,
The present invention relates to a fixing or pressurizing film used for a heat fixing unit of a toner image of a film fixing method of a device such as a facsimile or a printer.

[0002]

2. Description of the Related Art In a printing apparatus for forming a toner image, such as an electrophotographic copying machine, a facsimile, a printer, etc., at the final stage of printing or copying, the toner of the toner image formed on the recording paper is heated and melted on the recording paper. In general, a heat fixing method for fixing a toner image is used.

In such a heat fixing method, a heat roller fixing method has been widely used. In the heat roller fixing method, a recording paper having an electric heater inside and a heat roller whose outer periphery is coated with rubber or resin having good releasability is pressed against another rubber roller, and a toner image is formed between the rollers. And heats and fuses the toner to fuse the toner on the recording paper.

In the heat roller fixing method, the entire heat roller is heated, so that it is easy to maintain the roller at a predetermined temperature, which is suitable for speeding up the processing. Since the time required for heating to the temperature is required, there is a disadvantage that the waiting time from when the power is turned on to when the operation becomes possible becomes long. Further, since the entire heat roller must be heated, the power consumption is large.

Therefore, in recent years, a heat fixing method of a film fixing method using a film-like endless belt has been proposed.

In this fixing method using an endless belt, an endless belt for a fixing portion is spread over a plurality of rollers, another rubber roller for a fixing portion is pressed against a predetermined position on the outer surface thereof, and the endless belt at the pressed position is pressed. The heater is placed inside the belt in contact with the belt. Then, while rotating the endless belt and the roller, the recording paper on which the toner powder image is formed passes between the endless belt and the roller, and the toner is fused on the recording paper. In this fixing method, substantially only the pressure contact portion of the thin film belt is directly heated by the heater, so that the waiting time at the time of turning on the power is almost zero, and this is called an on-demand type heat fixing method. .

Since the above-described mechanism is used in the on-demand type heat fixing method, the endless belt used in the heat fixing method has sufficient heat resistance, elasticity, strength, insulating property on the inner surface of the belt, and separation of the outer surface of the belt. Demands for moldability. In order to respond to this, a belt made of a film for a fixing unit composed of two layers, an inner layer made of a heat-resistant resin and an outer layer made of a resin having releasability, is generally used.

The releasable layer of such a film for a fixing portion is very thin due to the requirement of thermal conductivity and the like. Usually, after a primer layer is provided on the inner heat-resistant resin layer as necessary,
It has been manufactured by applying a dispersion of a fluororesin or the like, drying and applying a heat treatment.

However, since the releasable layer manufactured by such a manufacturing method is formed by applying a resin, defects such as pinholes and cracks are likely to remain on the surface of the layer, and furthermore, the durability and abrasion resistance are reduced. A high fixing film has been demanded.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a fixing part film comprising a heat-resistant resin layer and a release resin layer, wherein the outer release layer has high durability, especially abrasion resistance. An object of the present invention is to provide a film for a fixing portion exhibiting properties.

[0011]

As a result of the research conducted by the present inventors, in the above-mentioned film for a fixing section, a fluororesin molded as a tube on a release layer was applied onto a heat-resistant resin layer. It has been found that high abrasion resistance of the release layer can be obtained.

Accordingly, the present invention is directed to a fixing part film comprising a heat-resistant resin layer and a release resin layer, wherein the heat-resistant resin layer is made of a thermosetting polyimide resin and the release resin layer is made of a heat-resistant resin. What provides a film for a fixing part characterized by being formed by applying a tube mainly composed of a fluororesin having an inner diameter of not more than 95% of the outer diameter of the resin layer and heat-sealing the tube. It is.

The fluororesin molded as such a tube has a lower melt index and higher mechanical strength such as tensile strength and bending resistance than those used for fluororesin dispersion.

Therefore, the fluororesin tube used in the fixing portion film of the present invention preferably has a bending resistance of 1,000,000 times or more, for example, 1,000,000 to 2,000,000 times.

The above-mentioned fluororesin tube preferably contains a fluororesin having a melt index of 2 (g / 10 min) or less as a main component.

Further, the above fluororesin tube is preferably made of a tetrafluoroethylene resin, a tetrafluoroethylene / perfluoroalkoxyethylene copolymer, or a tetrafluoroethylene / hexafluoropropylene copolymer.

[0017]

[0018]

The heat-resistant resin layer of the fixing portion film of the present invention preferably contains thermally conductive inorganic particles.

The above-mentioned melt index 2 (g / 10
The fluororesin of min) or less can be made into a dispersion, but is not practical because of poor film formability. The film for a fixing section of the present invention is manufactured by fusing a fluororesin tube formed by extrusion or the like onto a heat-resistant resin layer.

In the method of manufacturing a fixing film as described above by fusing such a fluororesin tube on a heat-resistant resin layer, the fluororesin already formed into a tube shape is integrally formed on the heat-resistant resin layer. In addition, it has been found that it is effective to perform treatment at a specific temperature after laminating a fluororesin tube on a heat-resistant resin layer in order to perform fusion so that a defect such as unevenness does not occur on the surface.

Accordingly, the present invention is a method for producing a film for a fixing section comprising the heat-resistant resin layer of the present invention and the release resin layer as described above.
The above-mentioned manufacturing method, wherein a fluororesin tube having an inner diameter of 95% or less of the outer diameter of the heat-resistant resin layer is laminated and treated at a temperature at least 50 ° C. higher than the melting point of the resin of the fluororesin tube. Is what you do. Furthermore, in order to fuse the fluororesin molded into a tube shape as described above on the heat-resistant resin layer integrally and without causing defects such as irregularities on the surface, the fluororesin tube must be specified in the radial direction. It has also been found that it is preferable to laminate on the heat-resistant resin layer in a state of being stretched at the ratio.

Therefore, in the method of the present invention, a fluororesin tube having an inner diameter of 95% or less of the outer diameter of the heat-resistant resin layer is used.

In another preferred embodiment of the method of the present invention, the inner surface of the fluororesin tube is etched before laminating the fluororesin tube on the heat-resistant resin layer.

In still another preferred embodiment of the method of the present invention, an unfolded fluororesin tube is used.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The fixing portion film of the present invention comprises an inner layer (heat-resistant resin layer) made of a heat-resistant resin and an outer layer (release resin layer) made of a release resin.

As the heat-resistant resin used for the heat-resistant resin layer, a thermosetting heat-resistant resin is selected in order to obtain particularly high heat resistance. In particular, when a use temperature of 150 ° C. or higher is intended, or in a fixing portion, the thermoplastic resin is inconvenient because the fixing film or the like is elongated.

By using a thermosetting heat-resistant resin for the heat-resistant resin layer, the insulating properties and high heat resistance of the film for the fixing portion are ensured. Examples of such a thermosetting heat-resistant resin include, for example, thermosetting resins such as polyimide, polyamideimide, polybenzimidazole, polybenzoxazole, polyphenylene sulfide, polyetheretherketone, polyethersulfone, and polyetherimide. No. Among these thermosetting heat-resistant resins, thermosetting polyimide and polyamideimide are particularly preferable.

Further, since these resins alone have a low thermal conductivity, it is preferable to contain insulating and thermally conductive inorganic particles.

The substance itself constituting such heat conductive inorganic particles may be the same as that which has been proposed as a substance to be added to the heat-resistant resin layer of the fixing portion belt, for example, boron nitride. , Alumina, silicon carbide, potassium titanate, aluminum nitride, mica, silica, titanium oxide, talc, calcium carbonate and the like.
These substances can be used as a mixture of two or more kinds. As a material constituting the thermally conductive inorganic particles,
Boron nitride, alumina, silicon carbide, and aluminum nitride are preferred, and boron nitride is particularly preferred.

The average particle size of the inorganic particles as described above is not particularly limited, and may be the same as the inorganic filler added to the ordinary resin composition, but a dispersibility and a smooth layer are obtained. From the viewpoint of the above, it is usually about 0.5 to 10 μm, preferably about 0.5 to 7 μm. If it is less than 0.5 μm, the effect of improving the thermal conductivity is small, and irregularities may be formed on the film due to aggregation of particles. If the average particle size of the particles exceeds 10 μm, the mechanical strength required for the heat-resistant resin layer may not be obtained depending on the content.

The content of the heat-conductive inorganic particles in the heat-resistant resin layer is not particularly limited, either.
From the viewpoint of maintenance of mechanical strength and the like, it is usually about 5 to 30% by volume, preferably about 10 to 25% by volume. Within this range, it is possible to improve the thermal conductivity and the rigidity while securing substantially the same flexibility as the layer made of the resin alone. If the content is less than 5% by volume, a sufficient effect of improving thermal conductivity cannot be obtained. If the content exceeds 30% by volume, flexibility and strength become insufficient, and cracks and breakage occur when used as a belt for a fixing portion. Tends to occur.

The shape of the thermally conductive inorganic particles may be any of spherical, scale-like (flat), fibrous, etc. Among them, the flat-shaped particles are preferred to obtain a film with little unevenness and a smooth surface. It is particularly preferable because the stiffness is higher than that of the spherical particle filler.

Although the thickness of the heat-resistant resin layer is not particularly limited, it is usually 10 to 200 μm, preferably 30 to 100 μm.
It is about μm.

A fluororesin is used as the releasing resin constituting the outer layer of the fixing portion film. The fluororesin is preferably one having excellent heat resistance so that the fixing unit belt can be continuously used at a high temperature of about 200 ° C., for example, tetrafluoroethylene resin (PTFE), tetrafluoroethylene / perfluoroalkoxyethylene Copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP) and the like.
PFA is particularly preferred.

In the fixing film of the present invention, a fluorine resin having a melt index (measured according to ASTM D-2116) of 2 (g / 10 min) or less is used. Such a fluororesin generally has a molecular weight of about 150,000 to 1,000,000, though depending on the type of the resin, and has a molecular weight larger than that of the fluororesin usually contained in the fluororesin dispersion. Yes, a film (tube) formed by extrusion or the like is laminated on the heat-resistant resin layer by a specific method of the present invention as described later, and heat-treated to be integrated with the heat-resistant resin layer.

The fluororesin tube formed by such extrusion molding is different from those formed by applying a fluororesin dispersion on a heat-resistant resin layer, drying and firing, etc. Since there are no surface defects such as cracks and the molecular weight is larger than that of the fluororesin used for dispersion, higher durability such as abrasion resistance can be obtained. Such a fluororesin tube has a bending resistance of 1,000,000 times or more, for example, 1,000,000 to 2,000,000 times (bending according to ASTM D-2176-69 under a load of 1.25 kg using a sample of 13 mm × 90 mm × 0.2 mm). (Measure the number of repeated bends until cracks occur)
It is preferable to have

The fluororesin of such a release layer may contain a conductive filler to impart conductivity, thereby preventing offset due to charging.

The kind of the conductive filler used for such a purpose is not particularly limited, and examples thereof include carbon black such as Ketjen black and metal powder such as aluminum. The average particle size of the conductive filler is preferably 0.5 μm or less in order to obtain stable and uniform conductivity.

The content of the conductive filler is usually about 0.1 to 5% by weight based on the resin. However, if the conductivity of the release resin layer is too high, when the toner on the recording paper comes into contact with the release resin layer of the fixing unit belt, the charge of the toner flows into the release resin layer, and the recording paper The suction force between the toner and the toner may be lost. In order to prevent such a phenomenon, the surface resistivity of the outer layer is set to 1 × 10 ¹² to 1 × 10 ¹⁵ Ω /.
□ is preferred.

The thickness of the fluororesin release layer is not particularly limited either, but is usually 5 to 100 μm, preferably 10 to 30 μm.
It is about μm.

Between the heat-resistant resin layer and the release resin layer,
In order to enhance the adhesiveness between the two, an intermediate layer (primer layer) made of a resin having adhesiveness may be provided on both layers of the resin. The primer layer can be made of, for example, a mixture of a fluororesin and polyamideimide, a mixture of a fluororesin and polyethersulfone, or the like. Those obtained by dissolving or dispersing these resins in a solvent are commercially available as primers for fluororesins and can be suitably used. Examples of such commercially available primers for fluororesin include, for example, Primer 855-001, Teflon 855-300 manufactured by DuPont Japan, and Polyflon EK manufactured by Daikin Industries, Ltd.
-1700, polyflon EK-1800, polyflon E
K-1900. Such a primer layer may also contain the conductive filler as described above. The thickness of the primer layer is usually 0.1 to 20 μm, preferably 1 to 1 μm.
It is about 0 μm.

Further, the method for producing the fixing portion film of the present invention will be described.

First, a tubular heat-resistant resin layer is formed by a method similar to that of a known fixing unit belt. For example, on a cylindrical mold, apply a varnish containing a resin or a precursor thereof for forming a heat-resistant resin layer as described above in a solvent,
The solvent is removed by heat treatment or the like. Thereafter, a resin composition for forming a primer layer is arbitrarily applied and dried, and, if necessary, a heat-resistant resin is fired to produce the resin composition.

When the heat-resistant resin is a thermosetting polyimide,
As a precursor of the heat-resistant resin, for example, an aromatic tetracarboxylic acid component and an aromatic diamine component can be used,
These can be reacted in an organic polar solvent to obtain the resin. Examples of the aromatic tetracarboxylic acid component include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, and pyromellitic dianhydride. There are anhydrides and the like, and these may be used as a mixture. Examples of the aromatic diamine component include diphenyl ether diamines such as 3,3′-diaminodiphenyl ether, 3,3′-dimethoxy-4,4′-diaminodiphenyl ether, and 4,4′-diaminodiphenyl ether;
Diphenylthioethers, diphenylthioether-based diamines such as 4,4′-diaminodiphenylthioether,
Benzophenone diamines such as 4,4'-diaminobenzophenone, and other diphenylmethane diamines such as paraphenylenediamine and metaphenylenediamine can be given. Examples of the organic polar solvent include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, phenol, o-cresol, m-cresol, p-cresol, dimethyloxide and the like.

The primer layer can be formed from a fluororesin primer as described above.

A fluororesin tube is laminated on the heat-resistant resin layer (and optionally a primer layer) formed as described above, and is fused and integrated with the heat-resistant resin layer. In order to laminate the fluororesin tube on the heat-resistant resin layer, conventionally, a heat-shrinkable fluororesin tube is used, and a fluororesin tube having a diameter larger than the heat-resistant resin layer is fitted on the heat-resistant resin layer. However, a thin fluororesin layer as intended in the present invention, particularly a fluororesin film having a thickness of 10 to 30 μm, is difficult to obtain sufficient heat shrinkage, and a heat-resistant resin is used. It was found that the layer and the fluororesin layer could not be sufficiently adhered.
Therefore, as a result of various studies, a fluororesin tube having a diameter smaller than the diameter of the heat-resistant resin layer is laminated on the heat-resistant resin layer, and then heat treatment is performed at a specific temperature to cause defects such as wrinkles on the surface of the fluororesin tube. It was found that the two could be sufficiently fused and integrated without the need.

In order to laminate a fluororesin tube having a diameter smaller than the diameter of the heat-resistant resin layer on the heat-resistant resin layer as described above, the fluororesin tube is expanded in the radial direction within a range where permanent elongation does not occur. During this time, a heat-resistant resin layer may be inserted into the fluororesin tube, and then the stretched fluororesin tube may be returned to its original state.

Various methods are conceivable for fixing the fluororesin tube in a state of being extended in the radial direction in order to insert the heat-resistant resin layer into the fluororesin tube. For example, FIG. 1 is a schematic sectional view. As described above, the fluororesin tube 2 having an inner diameter smaller than the diameter of the heat-resistant resin layer is passed through the cylindrical mold 1 having an inner diameter slightly larger than the intended diameter of the heat-resistant resin layer, and both ends thereof are folded back to the outside of the mold. By pressing through the hole 3 provided in the mold 1 to reduce the pressure between the mold 1 and the tube 2 and bringing the tube 2 into close contact with the mold 1, the tube 2 can be extended in the radial direction and fixed. it can.

Thereafter, the heat-resistant resin layer 5 formed on the metal core 4 is inserted into the tube 2, the pressure between the mold 1 and the tube 2 is released, and the contraction force due to the restoring force of the tube 2 is used as the original. The tube 2 is returned to the diameter so that the heat resistant resin layer 5
In close contact. At this time, since the original inner diameter of the fluororesin tube 2 is smaller than the outer diameter of the heat-resistant resin layer, the fluororesin tube 2 is in close contact with the heat-resistant resin layer 5 in a state of being expanded in the radial direction and expanded.

When the fluororesin tube is adhered to the heat-resistant resin layer by the contraction force of the fluororesin tube, the inner diameter of the tube made of the fluororesin is 95% or less of the outer diameter of the heat-resistant resin layer, preferably 93% or less. %, It was found that sufficient adhesion between both layers could be obtained together with the subsequent heat treatment. However, if the elongation is too large, the fluororesin tube will be permanently plastically deformed and no shrinkage force will be obtained, so the inner diameter of the fluororesin tube must be at least 80% of the outer diameter of the heat-resistant resin layer.

Thereafter, the heat-resistant resin layer and the fluororesin tube laminated as described above are taken out of the mold and heated and fired to fuse and integrate the fluororesin tube with the heat-resistant resin layer.
At this time, the melting point of the fluororesin used should be at least 5
It has been found that sufficient fusion can be obtained by heating at a temperature higher than 0 ° C., preferably 70 ° C. or higher. For example, when the fluororesin is PFA, the melting point is about 310 ° C., so that the heating is performed at a temperature of 360 ° C. or more.

The heating time depends on the type of fluororesin, the thickness of the layer,
Depending on the thickness, material, heating temperature, etc. of the core, PFA should be 3
When heating at 60 ° C., it takes about 20 to 40 minutes.

After the above heat treatment, the two integrated layers are removed from the metal core to obtain the fixing film of the present invention.

In the above-described production, the adhesive strength between the two layers can be increased by etching the inner surface of the fluororesin tube before laminating the fluororesin tube on the heat-resistant resin layer. Etching can be performed by a conventionally known etching method, and can be performed by chemical etching such as sodium-naphthalene method and liquid ammonia method, and physical etching such as excimer laser method and low-temperature plasma method.

As the fluororesin tube used for producing the fixing film of the present invention, a commercially available fluororesin tube can be used, and such a commercially available fluororesin tube is folded into a tape shape. It is often distributed in a wound state. In such a tube, two folds are provided on the circumference in the length direction, and a portion outside the fold is in an extended state. When this is laminated on a cylindrical heat-resistant resin layer, the extended portion is likely to remain as a linear concave portion on the surface of the fluororesin layer, but surface defects due to such folds are also present as described above. According to the method of the invention, the problem can be solved because the tube is sufficiently stretched. However, when forming a relatively thick fluororesin layer (for example, about 30 to 100 μm),
It is preferable to use an unfolded fluororesin tube.

The fixing part film of the present invention produced as described above has a particularly excellent abrasion resistance because it has a release resin layer derived from a fluororesin tube obtained by extrusion molding. A significantly longer service life compared to conventional films.

[0059]

EXAMPLES Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited to only these Examples.

Example 1 A commercially available varnish containing a polyimide precursor (U Varnish S, manufactured by Ube Industries) was applied on a cylindrical metal core, and the inner diameter was 31 mm.
Was mounted on a core body and allowed to fall naturally to obtain a coating film.
The obtained coating film was heated to 300 ° C. for 30 minutes, and after cooling, pulled out of the core, and had a thickness of 50 μm, an outer diameter of 30 mm, and a length of 330.
mm polyimide tube was obtained. A cylindrical stainless steel shaft having a diameter of 29.97 mm was inserted into the polyimide tube to obtain a support.

On the other hand, the same shape as that shown in FIG.
A PFA tube with a diameter of 28 mm (93% of the outer diameter of the polyimide tube), a length of 380 mm, and a thickness of 10 μm (450HP-J, Mitsui Co., Ltd.) was placed inside a mold having an inner diameter of 31.5 mm and a hole with a diameter of 1 mm at the end. (Made of DuPont Fluorochemicals, PFA having a melt index of 2 (g / 10 min)), and both ends were folded back on a mold to be fixed. The PFA tube was expanded by reducing the pressure through the hole of the above mold, and was brought into close contact with the inner surface of the mold.

Thereafter, the shaft equipped with the polyimide tube was inserted into a mold, and the pressure was released to cover the polyimide tube with the PFA tube.

This was heat-treated at 380 ° C. for 30 minutes to obtain a fixing film of the present invention. The thickness of the release resin layer of the obtained film for the fixing part was about 10 μm.

Example 2 A commercially available polyimide tube (outer diameter 40 mm, length 325)
mm, thickness 75 μm, manufactured by Gunze Co., Ltd .;
3.8%), 325 mm long, 15 μm thick PFA tube (P76P, manufactured by Asahi Glass, melt index 2 (g)
/ 10 min) of PFA), and the polyimide tube was coated with the PFA tube in the same manner as in Example 1.

This was heat-treated at 390 ° C. for 25 minutes to obtain a fixing film of the present invention. The thickness of the release resin layer of the obtained film for the fixing portion was about 15 μm.

Comparative Example 1 A polyimide tube was molded in the same manner as in Example 1,
FA resin dispersion (530CL, manufactured by DuPont)
Was applied by spraying, and the film was heat-treated at 380 ° C. for 30 minutes to obtain a film for a fixing portion. The thickness of the release resin layer of the obtained film for the fixing part was about 10 μm.

When the MI of PFA contained in the PFA resin dispersion was separately measured, it was 13 (g / 10 min).
Met.

Comparative Example 2 A PFA resin dispersion (500CL, manufactured by Dupont) was spray-coated on the same polyimide tube as in Example 2, and the film was heat-treated at 390 ° C. for 25 minutes to obtain a film for a fixing portion. The thickness of the release resin layer of the obtained film for the fixing portion was about 15 μm.

When the MI of PFA contained in the PFA resin dispersion was separately measured, it was 13 (g / 10 min).
Met.

Comparative Example 3 A polyimide tube was formed in the same manner as in Example 1, and a PFA tube (450HP-J, 450 mm) having an inner diameter of 29 mm (97% of the outer diameter of the polyimide tube), a length of 325 mm, and a thickness of 10 μm was formed on the surface. (Manufactured by Du Pont-Mitsui Fluorochemicals) in the same manner as in Example 1. 380 ℃
For 30 minutes to obtain a fixing film.

The thickness of the release resin layer of the obtained film for the fixing portion was about 10 μm. Further, in this fixing portion film, a linear concave portion derived from the fold of the fluororesin tube was observed on the surface.

The fluororesin tubes used in the above Examples and Comparative Example 3 were all wound up in a tape shape, and had two folds in the length direction before use. However, after forming the fixing film, the concave portion derived from the crease of the tube was observed in Comparative Example 3.
Only those.

The fixing unit films obtained in Examples and Comparative Examples obtained above were incorporated into a printer, and an image test by printing at a copy speed of A4 paper at 20 sheets / min and a durability test by paper passing were performed. The results are shown in the table below.

[0074]

[Table 1] From the above results, the film for the fixing unit of the present invention is a release layer formed by applying a fluororesin dispersion,
Alternatively, the durability including abrasion resistance is remarkably improved as compared with a fixing film having a release layer derived from a fluororesin tube not expanded at a specific ratio found in the present invention. It is clear that.

[0075]

According to the film for a fixing portion of the present invention, a facsimile, a printer, and the like having significantly improved abrasion life as compared with a conventional fixing film and excellent durability can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a method for producing a fixing film of the present invention.

[Explanation of symbols]

 1. . . Mold 2. . . Fluororesin tube 3. . . 3. Hole in mold . . Core metal 5. . . Heat resistant resin layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-212837 (JP, A) JP-A-7-246671 (JP, A) JP-A-7-178741 (JP, A) JP-A-7-27 156287 (JP, A) JP-A-7-199699 (JP, A) JP-A-8-286536 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/20-15 / 20 101 B32B 27/00

Claims (8)

(57) [Claims] 1. A fixing unit film comprising a heat-resistant resin layer and the release resin layer, a heat-resistant resin layer is a thermosetting Po
Made of polyimide, the release resin layer is the outer diameter of the heat-resistant resin layer
A film for a fixing part, which is formed by applying a tube mainly composed of a fluororesin having an inner diameter of 95% or less of the above and heat-sealing the tube. 2. The fixing part film according to claim 1, wherein the fluororesin tube has a refraction resistance of 1,000,000 times or more. 3. The film for a fixing part according to claim 1, wherein the fluororesin tube contains a fluororesin having a melt index of 2 (g / 10 min) or less as a main component. 4. The fixing part film according to claim 1, wherein the heat-resistant resin layer contains thermally conductive inorganic particles. 5. The method according to claim 1, wherein the fluororesin of the release resin layer comprises a tetrafluoroethylene resin, a tetrafluoroethylene / perfluoroalkoxyethylene copolymer, or a tetrafluoroethylene / hexafluoropropylene copolymer. The fixing unit film according to any one of the above. 6. A method for producing a film for a fixing part comprising the heat-resistant resin layer and the release resin layer according to claim 1, wherein the heat-resistant resin layer has a tubular shape. Heat resistance
The method according to claim 1, wherein a fluororesin tube having an inner diameter of 95% or less of the outer diameter of the conductive resin layer is laminated and treated at a temperature at least 50 ° C. higher than the melting point of the resin of the fluororesin tube. 7. The method according to claim 6, wherein the inner surface of the fluororesin tube is pre-etched before the fluororesin tube is laminated on the heat-resistant resin layer. 8. The method according to claim 6, wherein an unfolded fluororesin tube is used.