JP2002031978A - Pressurizing roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressurizing roll of low hardness with durability such that the release property for toner does not decrease even after the roll is continuously used for a long time and that sharp fixed images can be perpetually obtained. SOLUTION: A silicone rubber elastic layer 20 of 2 to 5 mm thickness, a fluorine rubber layer 30 of 12 to 40 μm thickness and a fluorocarbon resin layer 40 of 7 to 20 μm thickness are laminated on the outer circumference of a core metal 10. The elastic layer 20 exhibits 5 to 30 deg. JIS-A hardness and <=3 deg. changes in an absolute value in the JIS-A hardness after heated at 300 deg.C for 40 minutes in a sealed state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure roller used in a fixing device such as an electrophotographic image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art An image fixing apparatus such as a copying machine and a laser beam printer employs a method of fixing a toner image on paper by heat and pressure using a fixing roller and a pressure roller. For this reason, the pressure roller used must have an elastic layer to obtain an appropriate nip between the pressure roller and the fixing roller, and must have heat resistance to withstand use at a toner fixing temperature of about 200 ° C. It is. Furthermore, in order to suppress the toner from adhering to the roller surface,
Toner release properties are also required.

[0003] Therefore, as a structure of the pressure roller, conventionally, a silicone rubber elastic layer is formed on a cored bar, and a fluororubber layer and a fluororesin layer are coated on the outer periphery thereof to impart toner releasability. Or coated with a fluororesin tube.

The silicone rubber composition for forming the silicone rubber elastic layer of the pressure roller is required to withstand the above-mentioned use environment, ie, use at a fixing temperature of about 200 ° C. Material with reduced change in physical properties of rubber (JP-A-11-080)
No. 669) has been proposed.

However, when the release layer on the roller surface is formed by coating the fluororubber layer and the fluororesin layer, the dispersion of the raw material is applied to the surface of the silicone rubber elastic layer, and then the layer is formed. Therefore, it is necessary to perform the heat treatment at a temperature higher than the melting point of the fluororesin, that is, at a temperature of about 300 ° C.

[0006] Therefore, unless the silicone rubber composition suppresses the deterioration of the physical properties by the heat treatment at 300 ° C, the silicone rubber elastic layer of the pressure roller is thermally degraded at the time of processing, and the physical properties are reduced.

[0007] Even in the case of such a silicone rubber elastic layer, the silicone rubber composition of the silicone rubber composition is used for a relatively low-speed laser beam printer having a printing speed of about 6 sheets per minute and a total printing number of about 50K sheets. Commercialization was possible because of the high hardness and the small number of total sheets required for the product life.

However, in recent years, there has been a remarkable trend toward high speed and high durability in copiers, laser beam printers, and the like, and accordingly, the performance required of pressure rollers has become severe.

That is, by increasing the printing speed,
Since the fixing time per sheet is inevitably shortened, it is necessary to increase the nip width between the pressure roller and the fixing roller in order to obtain a clear fixed image. It is necessary to reduce the hardness of the layer.

On the other hand, by lowering the hardness of the silicone rubber elastic layer, the physical properties are greatly reduced due to the high-temperature heat treatment, and there is a case where the silicone rubber layer cannot be used for high-speed and high-durability models and is broken. As a result, the fluororubber layer and the fluororesin layer provided for ensuring the toner releasability may peel off, and the fixed image may be contaminated by the toner or cause paper jam.

One method for avoiding such a problem is to coat a fluororesin tube as a toner release layer. According to this method, since there is no high-temperature baking step at the time of processing the roller, there is no thermal deterioration of the silicone rubber elastic layer, and also, due to the thickness of the release layer itself,
Due to the increased strength of the roller, the hardness of the silicone rubber elastic layer can be reduced, and even in such a case, the roller can maintain the toner releasability without breaking.

However, in the pressure roller according to this method, since the thickness of the fluororesin tube is large, the microscopic hardness of the roller surface is increased, and the toner releasability is sometimes reduced. For this reason, in order to obtain a permanent clear image, a cleaning mechanism for the pressure roller and periodic maintenance may be required, which complicates the configuration of the fixing device and increases running costs. In some cases.

[0013]

In view of the above situation, the present invention employs a low-hardness silicone rubber elastic layer, and forms a fluororubber layer and a fluororesin thereon to provide a low-hardness silicone rubber layer. It is an object of the present invention to provide a pressure roller which has durability, does not deteriorate toner releasability even after long-term continuous use, and can permanently obtain a clear fixed image.

[0014]

According to the present invention, there is provided a pressure roller comprising at least a silicone rubber elastic layer, a fluororubber layer, and a fluororesin layer laminated on the outer periphery of a cored bar. The silicone rubber elastic layer has a thickness of 2 mm to 5 mm, a JIS-A hardness of 5 ° to 30 °, and an absolute value of a JIS-A hardness change after heating at 300 ° C. for 40 minutes in a sealed state. Is 3 ° or less, the fluoro rubber layer has a thickness of 12 μm to 40 μm, and the fluoro resin layer has a thickness of 7 μm to 20 μm.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS By setting the properties and shapes of the silicone rubber elastic layer, fluororubber layer and fluororesin layer within the above ranges, the toner releasability does not decrease even after long-term continuous use, and a clear fixed image is obtained. Can be obtained permanently. The details will be described below.

The JIS-A hardness of the silicone rubber composition for forming the silicone rubber elastic layer of the present invention is 5 ° or more and 30 or more.
° or less. For this reason, the hardness of the silicone rubber elastic layer is sufficiently low, a sufficient nip width can be secured between the pressure roller and the fixing roller, and a clear fixed image can be obtained.

For the same reason, the micro rubber hardness of the silicone rubber composition forming the silicone rubber elastic layer of the present invention is preferably 35 ° or more and 60 ° or less.

Further, the silicone rubber composition used in the present invention may be used at 300 ° C. in a state sealed with aluminum foil.
JIS-A before and after heat treatment (sealing aging test) for 40 minutes
Those having a change in hardness within ± 3 ° are used. By using such a silicone rubber composition, deterioration of the silicone rubber elastic layer is suppressed in the sintering step at the time of forming the fluororubber layer and the fluororesin layer, so that good properties are maintained even after long-term continuous use. A pressure roller can be manufactured.

For the same reason, the change in the micro rubber hardness of the silicone rubber composition forming the silicone rubber elastic layer of the present invention before and after the sealing aging test is preferably within ± 2 °.

In order to realize the above-mentioned properties relating to hardness, a silicone rubber composition is required to have an organopolysiloxane (A) having an alkenyl group directly bonded to at least two silicon atoms in a molecule; And an organohydrogenpolysiloxane (B) having a hydrogen atom (active hydrogen) directly bonded to at least two silicon atoms.

The silicone rubber raw material is excellent in processability, has good dimensional stability due to no generation of by-products due to the curing reaction, and has stable physical properties after curing. Thus, the addition reaction crosslinked silicone rubber, particularly the addition reaction crosslinked liquid silicone rubber, is preferred.

The organopolysiloxane (A) is a base polymer of a silicone rubber raw material, and its molecular weight is not particularly limited. However, from the viewpoints of processing characteristics, characteristics of the obtained silicone rubber composition, and the like, the viscosity of the organopolysiloxane (A) has a lower limit of 10P.
a · s or more is preferable, 50 Pa · s or more is more preferable, and the upper limit is preferably 300 Pa · s or less,
00 Pa · s or less is more preferable.

The alkenyl group of the organopolysiloxane (A) is selected from the group consisting of the organohydrogenpolysiloxane (B)
Is a site that reacts with active hydrogen to form a cross-linking point, and the type thereof is not particularly limited, but is preferably at least one of a vinyl group and an allyl group because of high reactivity with active hydrogen. And a vinyl group is particularly preferred.

The organohydrogenpolysiloxane (B) functions as a crosslinking agent for the addition reaction in the curing step. The number of silicon-bonded hydrogen atoms in one molecule is 2 or more, and the curing reaction is optimized. 3
More than one relatively low molecular weight polymer is preferred.

Here, the molar ratio of the hydrogen atom (active hydrogen) of the organohydrogenpolysiloxane (B) to the alkenyl group of the organopolysiloxane (A) is as follows:
It is preferably from 0.3 to 1.2.

When the organopolysiloxane (A) and the organohydrogenpolysiloxane (B) are used in the silicone rubber composition, the molar ratio of active hydrogen to alkenyl group may be theoretically 1. However, from the viewpoint of the properties of the obtained silicone rubber composition, conventionally, it has been general that the active hydrogen is excessively in a range of 1.3 or more and 2.0 or less.

On the other hand, when the molar ratio of active hydrogen to alkenyl groups is 0.3 or more and 1.2 or less, changes in JIS-A hardness and micro rubber hardness before and after the sealing aging test can be suppressed.

Although the reason is not clear, in the present invention, since the alkenyl group is excessive relative to the active hydrogen in the present invention, the unreacted alkenyl group immediately after the formation of the silicone rubber elastic layer is formed. Is considered to remain.

For this reason, even if the silicone rubber elastic layer is thermally degraded in the step of producing the fluororubber layer and the fluororesin layer by heating and baking, unreacted alkenyl groups react to cause thermal degradation. It is speculated that this is to compensate for the decline in performance.

The silicone rubber raw material of the present invention may optionally contain an inorganic filler, a platinum catalyst, a curing reaction inhibitor and the like.

The inorganic filler is appropriately mixed in order to improve the mechanical strength, heat resistance, electrical properties, etc. of the cured silicone rubber composition. And alumina powder, and these can be used in combination.

Further, if necessary, the fumed silica subjected to the hydrophobizing treatment, the hydrophilic fumed silica not subjected to the hydrophobizing treatment, and the silanol groups on the surfaces of the fine particles of the dry silica are treated with an organosiloxane group and / or an organosiloxane group. Silica-based fillers such as those subjected to hydrophobic treatment by blocking with silyl groups; inorganic fillers such as calcium carbonate and diatomaceous earth; fillers for improving heat resistance such as iron oxide, zinc carbonate, titanium oxide and carbon black Etc. may be added.

In order to realize good characteristics of the pressure roller without deteriorating other characteristics, the amount of the filler is adjusted according to the amount of the organopolysiloxane (A) and the organohydrogenpolysiloxane (B). The amount is preferably from 0.1 part by mass to 100 parts by mass with respect to 100 parts by mass in total.

The platinum-based catalyst is used in the form of a platinum compound which can be easily dispersed in the raw material of silicone rubber, and its compounding amount is generally preferably from 1 ppm to 100 ppm as platinum, but is not limited to this range. Is appropriately selected depending on the pot life, curing time, product shape, and the like.

Examples of the curing reaction inhibitor include acetylene alcohols, cyclic methylvinylsiloxane, and siloxane-modified acetylene alcohols.

The viscosity of the silicone rubber raw material in which the necessary fillers and the like are blended is not particularly limited, but is preferably from 10 Pa · s to 300 Pa · s from the viewpoint of moldability.

The thickness of the silicone rubber elastic layer composed of the silicone rubber composition described above should be 2 mm or more and 5 mm or more.
mm or less. By setting the thickness of the silicone rubber elastic layer in this range, a sufficient nip width can be realized between the pressure roller and the fixing roller, the destruction of the silicone rubber elastic layer can be suppressed, and good characteristics of the pressure roller can be obtained. Can be maintained for a long time.

The thickness of the fluororubber layer in the present invention is 12
It is set to be at least 40 μm. By setting the thickness of the fluororubber layer to this range, good releasability of the toner can be realized, and destruction and peeling of the fluororubber layer can be suppressed.
Good characteristics of the pressure roller can be maintained for a long time.

The fluororubber layer is coated with a water-soluble paint in which a tetrafluoroethylene-hexafluoropropylene copolymer (FEP) and a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA) are dispersed in a fluororubber latex. Then, it can be formed by firing.

As the fluororubber latex, a latex of vinylidene fluoride-hexafluoropropylene copolymer (FKM) is preferably used.

The thickness of the fluororesin layer in the present invention is 7 μm.
m and 20 μm or less. By setting the thickness of the fluororesin layer in this range, it is possible to realize good toner releasability, suppress destruction and peeling of the fluororesin layer, and maintain good characteristics of the pressure roller for a long time. it can.

The fluororesin layer is made of an aqueous solution in which a tetrafluoroethylene-hexafluoropropylene copolymer (FEP), a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE) and the like are dispersed. It can be formed by applying a paint and firing.

Hereinafter, an example of a method of manufacturing the pressure roller disclosed in the present invention will be described with reference to FIG.

First, the silicone rubber raw material is heated and cured at 140 ° C. for 8 minutes, for example, at 140 ° C. using a cylindrical forming mold to form the silicone rubber elastic layer 20. As the core metal, any material such as aluminum, iron, and stainless steel may be used as long as there is no problem in mechanical strength.
Particularly, aluminum is preferably used because it can be reduced in weight and hardly corroded. Prior to forming the silicone rubber elastic layer, the core metal may be subjected to a primer treatment.

Next, heat treatment is performed at 200 ° C. for 4 hours, for example, to stabilize the physical properties of the silicone rubber elastic layer after curing, and to remove reaction residues and unreacted low molecular components in the silicone rubber elastic layer. .

Thereafter, on the surface of the obtained silicone rubber elastic layer, a dispersion in which a fluororubber and a fluororesin are dispersed in an aqueous paint is applied to a required film thickness by, for example, a spray method. Prior to the coating, the silicone rubber elastic layer may be subjected to a primer treatment.

Then, by baking by heat treatment at 300 ° C. for 40 minutes, for example, the fluororubber layer 30 and the fluororesin layer 40 are formed.

In the present invention, if necessary,
A primer layer, an adhesive layer, and the like can also be formed.
In addition, functional layers such as a base layer, a barrier layer, and a diffusion prevention layer can be formed.

If a pressure roller manufactured by the above method is used, a high-quality fixed image can be maintained for a long period of time. Therefore, the fixing roller of the present invention can be used in an image forming apparatus such as a copying machine and a laser beam printer. It is suitably arranged in the fixing device.

[0050]

The present invention will be described in more detail with reference to the following Examples, which do not limit the present invention in any way. Unless otherwise specified below, commercially available high-purity reagents were used.

First, JIS-A of the silicone rubber composition
The hardness and micro rubber hardness, and a method for evaluating a heat resistance test (sealing aging test) in a sealed state will be described.

(A) JIS-A of silicone rubber composition
Hardness (°): A silicone rubber raw material is charged into a test piece mold, cured at 120 ° C. × 10 minutes, and then heat-treated at 200 ° C. × 4 hours in an oven to produce a test piece having a thickness of 6 mm. . JI of the obtained test piece
The SA hardness was measured according to JIS K6301.

(A) Micro rubber hardness (°) of the silicone rubber composition: The silicone rubber raw material was cured by heating at 140 ° C. for 8 minutes on a metal core using a cylindrical mold, and then heated in an oven at 200 ° C. Heat treatment was performed at 4 ° C. × 4 hours to produce a roller-shaped test piece. The hardness of the obtained roller was measured using an Asker Micro Rubber Hardness Tester MD-1C (manufactured by Takaseki Keiki Co., Ltd.), and the result was taken as the micro rubber hardness of the silicone rubber composition.

(C) Sealing aging test: The test piece produced by the above method was wrapped in aluminum foil and placed in an oven for 30 minutes.
Heat treatment was performed at 0 ° C. × 40 minutes. After the heat treatment, the hardness was measured by the same method as above, and the change in hardness before and after the heat treatment was confirmed.

(Example 1) Pressure roller 1 An addition-reaction crosslinked liquid silicone rubber DY35-2063 (manufactured by Dow Corning Toray Silicone Co., Ltd.) was used as a silicone rubber raw material according to the above method (a).
A silicone rubber elastic layer was formed on an aluminum core having a diameter of φ12 mm.

Next, a primer GLP103SR (manufactured by Daikin Industries, Ltd.) is placed on the obtained silicone rubber elastic layer.
Is applied in a thickness of 4 μm, and a fluoro rubber dispersion GLS213 (manufactured by Daikin Industries, Ltd.) containing a fluororesin is spray-coated thereon so as to have a thickness of 30 μm.
Further, a fluororesin dispersion Teflon (registered trademark) 855-601 (manufactured by DuPont-Mitsui Fluorochemical Co.) was applied so as to have a film thickness of 8 μm. Thereafter, a heat treatment was performed in an oven at 300 ° C. for 40 minutes to form a fluororubber layer and a fluororesin layer.

Various characteristics of the obtained pressure roller 1 were evaluated, and the results are shown in Table 1. From Table 1, the following became clear.

First, JIS-
Since the A hardness is 20 ° and the molar ratio of active hydrogen to alkenyl groups in the silicone rubber raw material is 0.9,
The JIS-A hardness after the seal aging test did not change to 20 °. Further, the micro rubber hardness of the silicone rubber composition was 56.30 °, and after the seal aging test, it was 57.83 °, and the change was small.

Second, the thickness of the silicone rubber elastic layer is 2.35 mm, the thickness of the fluoro rubber layer is 30 μm, and the thickness of the fluoro resin layer is 8 μm. After passing 150,000 sheets, the pressing roller 1
Maintained good properties.

(Comparative Example 1) Pressure roller 2 Same as the case of pressure roller 1 except that an addition-reaction crosslinked liquid silicone rubber DY35-561 (manufactured by Dow Corning Toray Silicone Co., Ltd.) was used as a silicone rubber raw material. Thus, the pressure roller 2 was manufactured.

Various characteristics of the obtained pressure roller 2 were evaluated, and the results are shown in Table 1. As is clear from Table 1, since the molar ratio of active hydrogen to alkenyl groups in the silicone rubber raw material used in the production of the pressure roller 2 is 1.3, the JIS-A hardness after sealing aging test is 4 °. The micro rubber hardness also decreased by 3.93 °. Also,
At the time when 47,000 sheets were passed, the silicone rubber elastic layer was broken.

Comparative Example 2 Pressure Roller 3 The pressure roller 3 was manufactured in the same manner as the pressure roller 1 except that the thickness of the silicone rubber elastic layer was 1.85 mm.

Various characteristics of the obtained pressure roller 3 were evaluated, and the results are shown in Table 1. As is clear from Table 1, when 50,000 sheets were passed, the silicone rubber elastic layer was broken.

(Example 2) Pressure roller 4 An addition-reaction cross-linkable liquid silicone rubber DY35-1198 (manufactured by Dow Corning Toray Silicone Co., Ltd.) was used as a silicone rubber raw material according to the above method (a).
A silicone rubber elastic layer was formed on an aluminum core having a diameter of φ14 mm.

Next, the surface of the obtained silicone rubber elastic layer is treated with a primer, and a fluoro rubber dispersion GLS213 (manufactured by Daikin Industries, Ltd.) containing a fluoro resin is spray-coated thereon so as to have a thickness of 15 μm. Further, a fluororesin dispersion ENA020-29 (manufactured by DuPont-Mitsui Fluorochemicals Co.) was applied so as to have a film thickness of 8 μm. Thereafter, heat treatment was performed in an oven at 300 ° C. for 40 minutes to form a fluororubber layer and a fluororesin layer, and the pressure roller 4 was manufactured.

Various characteristics of the obtained pressure roller 4 were evaluated, and the results are shown in Table 1. From Table 1, the following became clear.

First, the JIS-
Since the A hardness is 11 ° and the molar ratio of active hydrogen to alkenyl groups in the silicone rubber raw material is 0.9,
The JIS-A hardness after the seal aging test decreased only 1 °. The micro rubber hardness of the silicone rubber composition was 41.90 °, and after the sealing aging test, it was 42.90 °.
80 ° and the change was small.

Second, the thickness of the silicone rubber elastic layer is 3.60 mm, the thickness of the fluororubber layer is 15 μm, and the thickness of the fluororesin layer is 8 μm. After passing 150,000 sheets, the pressure roller 4
Maintained good properties.

(Comparative Example 3) Pressure Roller 5 Except for using an addition-reaction cross-linkable liquid silicone rubber XE15-B7526 (GE Toshiba Silicone Co., Ltd.) as a silicone rubber raw material, the same procedure as in the case of the pressure roller 4 was used. The pressure roller 5 was manufactured.

Various characteristics of the obtained pressure roller 5 were evaluated, and the results are shown in Table 1. As is clear from Table 1, since the molar ratio of active hydrogen to alkenyl groups in the silicone rubber raw material used in the production of the pressure roller 5 is 1.3, the JIS-A hardness after sealing aging test is 4 °. The micro rubber hardness also decreased by 6.60 °. Also,
When 100,000 sheets were passed, the fluororubber layer peeled off.

COMPARATIVE EXAMPLE 4 Pressure Roller 6 A pressure roller 6 was manufactured in the same manner as in the case of the pressure roller 4 except that the thickness of the fluorine rubber layer was changed to 10 μm.

Various characteristics of the obtained pressure roller 6 were evaluated, and the results are shown in Table 1. As is clear from Table 1, 10
The peeling of the fluororubber layer occurred when 10,000 sheets were passed.

Comparative Example 5 Pressure Roller 7 The pressure roller 7 was manufactured in the same manner as the pressure roller 4 except that the thickness of the fluororesin layer was 6 μm.

Various characteristics of the obtained pressure roller 7 were evaluated, and the results are shown in Table 1. As is clear from Table 1, peeling of the fluororesin layer occurred when 50,000 sheets were passed.

[0075]

[Table 1]

[0076]

According to the pressure roller of the present invention, the silicone rubber elastic layer has a thickness of 2 to 5 mm.
IS-A hardness is 5 ° to 30 ° and 30 in sealed state
The absolute value of the change in JIS-A hardness after heating at 0 ° C for 40 minutes is 3
° or less; the fluororubber layer has a thickness of 12 µm to 4 µm.
0 μm; the fluororesin layer has a thickness of 7 μm to 20 μm.
Since the thickness is set to μm, the toner has low hardness and durability, and does not decrease the toner releasability even after long-term continuous use, so that a clear fixed image can be obtained permanently.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view for explaining an example of a pressure roller of the present invention.

[Explanation of symbols]

 Reference Signs List 10 core metal 20 silicone rubber elastic layer 30 fluorine rubber layer 40 fluorine resin layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F16C 13/00 F16C 13/00 EF term (reference) 2H033 AA09 AA20 AA25 BB05 BB06 BB14 BB15 BB29 BB30 BB31 3J103 AA02 AA15 AA33 AA51 BA31 BA41 FA02 FA07 FA12 FA18 GA02 GA52 GA57 GA58 HA03 HA04 HA05 HA12 HA15 HA32 HA33 HA37 HA53 HA54 4J002 CP04X CP13W CP14W GM00

Claims (6)

[Claims] 1. A pressure roller in which at least a silicone rubber elastic layer, a fluororubber layer and a fluororesin layer are laminated on the outer periphery of a cored bar, said silicone rubber elastic layer having a thickness of 2 to 5 mm. The JIS-A hardness is 5 ° to 30 °, the absolute value of the JIS-A hardness change after heating at 300 ° C. for 40 minutes in a sealed state is 3 ° or less,
The fluororubber layer has a thickness of 12 μm to 40 μm,
A pressure roller, wherein the fluororesin layer has a thickness of 7 μm to 20 μm. 2. The micro rubber hardness of the silicone rubber elastic layer is 35 ° to 60 °, and 300 ° C. in a sealed state.
The absolute value of the change in micro rubber hardness after heating for 40 minutes is 2 °
The pressure roller according to claim 1, wherein: 3. The silicone rubber elastic layer comprises: an organopolysiloxane having an alkenyl group directly bonded to at least two silicon atoms in a molecule; and a hydrogen atom directly bonded to at least two silicon atoms in a molecule (active hydrogen). ) Is formed from a silicone rubber composition obtained by curing a silicone rubber raw material containing an organohydrogenpolysiloxane having a hydrogen atom (active hydrogen) mole ratio of 0.3 to the alkenyl group. To 1.
3. The pressure roller according to claim 1, wherein the pressure roller is 2. 4. The pressure roller according to claim 3, wherein the alkenyl group is at least one of a vinyl group and an allyl group. 5. The fluororubber layer is made of a tetrafluoroethylene-hexafluoropropylene copolymer (FEP).
5. The method according to claim 1, wherein a water-soluble paint in which a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA) is dispersed in a fluoro rubber latex is applied and fired. Pressure roller. 6. The fluororesin layer is formed of a tetrafluoroethylene-hexafluoropropylene copolymer (FE).
4. An aqueous coating material in which P), a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA) or polytetrafluoroethylene (PTFE) is dispersed, and formed by baking. 5. The pressure roller according to any one of 5.