JP6051763B2 - Fixing member, fixing device, and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing member, a fixing device, and an image forming apparatus.

In an image forming apparatus such as a copying machine or a printer using an electrophotographic system, an unfixed toner image formed on a recording sheet is fixed by a fixing device to form an image.
The fixing device includes, for example, a configuration including a heating roll and a pressure belt arranged in contact with the heating roll, or a pressure roll arranged in contact with the heating belt and the heating belt. There is known a fixing device called a belt nip system having a configuration.

For example, Patent Document 1 states that “the belt has a spiral groove on the inner surface, and a lubricant is applied between the belt and the sliding member, and at least the upstream side of the nip in the belt rotation direction slides with the belt. In a configuration having a space between the moving member and the support member, an image heating apparatus is disclosed in which the cross-sectional area of the space is different between the central portion and the end portion in the longitudinal direction.
Patent Document 2 states that “having at least a release layer, a metal layer provided on the inner surface of the release layer, and a sliding layer provided on the inner surface of the metal layer and forming a sliding surface, A “fixing belt whose sliding layer is made of a metal containing no nickel” is disclosed.
Patent Document 3 states that “a metal thin film formed on the inner peripheral surface of a cylindrical substrate via a release agent, and the inner peripheral surface of the metal thin film were closely stacked and laminated by centrifugal molding. An endless belt having a heat-resistant resin film is disclosed.

JP-A-2005-242113 JP 2005-241955 A Japanese Patent No. 3694890

  The subject of this invention is providing the fixing member which suppresses the raise of a sliding resistance with the member which contacts an internal peripheral surface.

The above problem is solved by the following means. That is,
The invention according to claim 1
A metal endless belt,
A heat-resistant resin layer provided on the inner peripheral surface of the endless belt and configured to include a heat-resistant resin;
Have
At least the inner peripheral surface of the heat resistant resin layer is composed of a porous structure having continuous pores,
A fixing member having a size of continuous pores of the porous structure and a size of continuous pores existing on an inner peripheral surface of the heat resistant resin layer is 1.0 μm or more and 100 μm or less.

The invention according to claim 2
The fixing member according to claim 1, wherein the heat-resistant resin layer has a thickness of 0.5 μm to 10 μm.

The invention according to claim 3
The fixing member according to claim 1, wherein a surface roughness Ra of an inner peripheral surface of the heat resistant resin layer is 0.1 μm or more and 3.0 μm or less.

The invention according to claim 4
A first rotating body made of a fixing member according to any one of claims 1 to 3
A second rotating body disposed in contact with the outer surface of the first rotating body;
A pressing member that is disposed inside the first rotating body and presses the first rotating body against the second rotating body from an inner peripheral surface of the first rotating body;
A fixing device.

The invention according to claim 5
An image carrier,
Charging means for charging the surface of the image carrier;
Latent image forming means for forming a latent image on the surface of the charged image carrier;
Developing means for developing the latent image with toner to form a toner image;
Transfer means for transferring the toner image to a recording medium;
Fixing means for fixing the toner image to the recording medium, the fixing means being the fixing device according to claim 4 ;
An image forming apparatus comprising:

According to the first aspect of the present invention, as compared with the case where the heat resistant resin layer is not provided on the inner peripheral surface of the metal endless belt, the fixing that suppresses the increase in the sliding resistance with the member in contact with the inner peripheral surface is suppressed. A member is provided.
According to the second aspect of the present invention, compared with the case where the thickness of the heat resistant resin layer is out of the above range, the increase in the heat capacity due to the heat resistant resin layer is suppressed, and the sliding resistance with the member in contact with the inner peripheral surface is reduced. A fixing member that suppresses the rise is provided.
According to the third aspect of the present invention, there is provided a fixing member that suppresses wear of the heat resistant resin layer as compared with the case where the surface roughness Ra of the inner peripheral surface of the heat resistant resin layer is outside the above range.
According to the first aspect of the present invention, there is provided a fixing member that suppresses the wear of the heat-resistant resin layer as compared with the case where at least the inner peripheral surface of the thermal resin layer is not configured with a porous structure.
According to the first aspect of the present invention, there is provided a fixing member that suppresses the wear of the heat resistant resin layer as compared with the case where the size of the continuous pores of the porous structure is outside the above range.

According to the inventions according to claims 4 and 5 , compared to a case where a fixing member not provided with a heat-resistant resin layer is provided on the inner peripheral surface of a metal endless belt, the fixing device and the image formation excellent in fixing maintenance An apparatus is provided.

It is a schematic cross-sectional view showing an example of a fixing member according to the present embodiment. 1 is a schematic configuration diagram illustrating an example of a fixing device according to a first embodiment. It is a schematic block diagram which shows an example of the fixing device which concerns on 2nd Embodiment. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment.

Embodiments that are examples of the present invention will be described below.
In addition, the same code | symbol is provided to the member which has the substantially same function throughout all the drawings, and the overlapping description may be abbreviate | omitted suitably.

[Fixing member]
The fixing member according to this embodiment will be described.
FIG. 1 is a schematic cross-sectional view showing an example of a fixing member according to the present embodiment.

The fixing member 110 (hereinafter referred to as “fixing belt 110”) according to the present embodiment includes, for example, a metal endless belt 110A (hereinafter referred to as “metal belt”), as shown in FIG. The belt 110A has the heat resistant resin layer 110B on the inner peripheral surface, and the metal belt 110A has the heat resistant elastic layer 110C and the heat resistant release layer 110D in this order.
In the fixing belt 110 according to the present embodiment, the heat-resistant elastic layer 110C and the heat-resistant release layer 110D are provided as necessary. When the heat-resistant elastic layer 110C and the heat-resistant release layer 110D are provided, image quality improvement and offset suppression (suppression of a phenomenon in which the toner image is fixed to the fixing belt) are easily realized during color fixing.

Here, it is known to use a metal endless belt as a fixing belt.
However, the fixing belt rotates while being contacted (or pressed) by a contact member (for example, a pressing member) from the inner peripheral surface thereof. For this reason, when a metal endless belt whose inner peripheral surface is a metal surface is used as a fixing belt, the sliding resistance with the contact member tends to increase. When this sliding resistance increases, it is difficult to achieve continuous fixing, and fixing maintenance tends to be reduced.

Therefore, in the fixing belt 110 according to the present embodiment, the heat resistant resin layer 110B is provided on the inner peripheral surface of the metal belt 110A. By providing the heat-resistant resin layer 110B, a member that contacts the inner circumferential surface of the fixing belt 110 is prevented from directly contacting the metal surface of the metal belt 110A, and the heat resistance that allows the sliding resistance to be easily maintained as compared with metal. It will be in the state which contacted the functional resin layer 110B.
For this reason, in the fixing belt 110 according to the present embodiment, an increase in sliding resistance with a member in contact with the inner peripheral surface is suppressed.
The fixing device and the image forming apparatus including the fixing belt 110 according to the present embodiment are excellent in fixing maintenance.

  Hereinafter, components of the fixing belt 110 according to the present embodiment will be described in detail. Note that the reference numerals are omitted.

(Metal belt)
The metal belt is composed of a metal endless belt.
Specifically, examples of the metal material constituting the metal belt include iron, nickel, titanium, copper, aluminum metal or alloys thereof, stainless steel, nickel alloy, titanium alloy, or copper alloy.

  The metal belt may have a single layer structure or a laminated structure of two or more layers. As a metal belt having a laminated structure, for example, a structure in which a metal layer (for example, a copper layer) is laminated on a base material layer (for example, a stainless steel layer), a metal layer (for example, a copper layer) on a base material layer (for example, a stainless steel layer). Layer) and a protective layer (for example, a stainless steel layer) are sequentially laminated.

  The thickness of the metal belt is, for example, preferably 30 μm or more and 70 μm or less, preferably 35 μm or more and 65 μm or less, more preferably 40 μm or more and 60 μm or less, from the viewpoint of maintaining the rigidity as the fixing belt.

(Heat resistant resin layer)
The heat resistant resin layer includes a heat resistant resin.
Examples of the heat resistant resin include polyimide, aromatic polyamide, liquid crystal material (for example, thermotropic liquid crystal polymer), polyester, polyethylene terephthalate, polyether sulfone, polyether ketone, polysulfone, polyimide amide, and the like. Is good.
Note that “heat resistance” means a characteristic that does not melt or decompose even when the temperature rises (for example, the fixing temperature) of the fixing device. The same applies hereinafter.

  Various additives may be blended in the heat resistant resin layer. Examples of additives include reinforcing agents (carbon black, etc.), fillers (calcium carbonate, etc.), softeners (paraffins, etc.), processing aids (stearic acid, etc.), anti-aging agents (amines, etc.), additives Examples include sulfurizing agents (sulfur, metal oxides, peroxides, etc.), functional fillers (alumina, etc.), and the like.

The surface roughness Ra of the inner peripheral surface of the heat resistant resin layer (the inner peripheral surface of the fixing belt) is preferably, for example, 0.1 μm or more and 3.0 μm or less, preferably 0.3 μm or more and 2.5 μm or less, More desirably, it is 0.5 μm or more and 2.0 μm or less.
When the surface roughness Ra is in the above range, when a release agent is interposed between the fixing belt and a member in contact with the inner peripheral surface thereof, the release agent is held on the inner peripheral surface of the heat resistant resin layer. As a result, reduction in sliding resistance with a member in contact with the inner peripheral surface of the fixing belt is maintained, and wear of the heat-resistant resin layer is easily suppressed.
The surface roughness Ra of the inner peripheral surface of the heat resistant resin layer is adjusted by, for example, the surface roughness Ra of the metal belt.

  The surface roughness Ra is measured using a surface roughness meter Surfcom 1400A (manufactured by Tokyo Seimitsu Co., Ltd.) according to JIS B0601-1994, with an evaluation length Ln of 4 mm, a reference length L of 0.8 mm, and a cutoff. The measurement is performed under the measurement conditions with a value of 0.8 mm.

The inner peripheral surface of the heat resistant resin layer (the inner peripheral surface of the fixing belt) is preferably configured with, for example, a porous structure having continuous holes. As a result, when a release agent is interposed between the fixing belt and a member in contact with the inner peripheral surface of the fixing belt, the release agent is easily held in the pores of the porous body. Reduction in sliding resistance with the member in contact with the inner peripheral surface is maintained, and wear of the heat resistant resin layer is easily suppressed.
The heat-resistant resin layer may have a single-layer structure in which the entire layer is composed of a porous structure (that is, a porous layer), or the outer peripheral surface (surface in contact with the metal belt) side is a non-porous layer. And a multilayer structure in which the inner peripheral surface side is formed of a porous layer.

The porous body constituting the inner peripheral surface of the heat-resistant resin layer shows a state in which a large number of continuous holes extend from the inner peripheral surface to the inside of the heat-resistant resin layer, and needs to be penetrated.
The size of the continuous pores of the porous body is, for example, from 0.01 μm to 100 μm, preferably from 0.05 μm to 80 μm, more preferably from 1.0 μm, from the viewpoint of holding the release agent and suppressing wear. It is 70 μm or less.
The size of the continuous hole means the opening diameter of the continuous hole existing on the inner peripheral surface of the heat resistant resin layer.
The size of the continuous hole is obtained by taking a part including the inner peripheral surface of the heat-resistant resin layer, using this as a measurement sample, and multiplying the surface of the measurement sample corresponding to the inner peripheral surface by a scanning electron microscope. The image is observed at 20,000 times, and the image is processed with image processing software (standard mode) to determine the maximum diameter of the opening of the continuous hole. This is calculated | required about 100 opening of a continuous hole, and let the average value be a magnitude | size of a continuous hole.
Here, the continuous hole is a hole formed by connecting at least two bubbles from the inner peripheral surface to the inside in the heat resistant resin layer, or continuously from the inner peripheral surface to the inside. It means the formed holes.

The thickness of the heat resistant resin layer is, for example, preferably from 0.5 μm to 10 μm, desirably from 0.7 μm to 8 μm, and more desirably from 1.0 μm to 7 μm.
When the thickness is within the above range, an increase in sliding resistance with a member in contact with the inner peripheral surface is easily suppressed while an increase in heat capacity due to the heat resistant resin layer is suppressed.

(Heat resistant elastic layer)
The heat resistant elastic layer includes, for example, a heat resistant elastic body.
Examples of the heat resistant elastic body include silicone rubber and fluororubber.
Examples of the silicone rubber include RTV silicone rubber, HTV silicone rubber, and the like. Specifically, polydimethyl silicone rubber (MQ), methyl vinyl silicone rubber (VMQ), methyl phenyl silicone rubber (PMQ), fluorosilicone. Rubber (FVMQ) etc. are mentioned.
Examples of the fluororubber include vinylidene fluoride rubber, tetrafluoroethylene / propylene rubber, tetrafluoroethylene / perfluoromethyl vinyl ether rubber, phosphazene rubber, and fluoropolyether.

  Various additives may be blended in the heat resistant elastic layer. Examples of additives include reinforcing agents (carbon black, etc.), fillers (calcium carbonate, etc.), softeners (paraffins, etc.), processing aids (stearic acid, etc.), anti-aging agents (amines, etc.), additives Examples include sulfurizing agents (sulfur, metal oxides, peroxides, etc.), functional fillers (alumina, etc.), and the like.

  The thickness of the heat resistant elastic layer is, for example, preferably from 0.1 mm to 0.5 mm, and more preferably from 0.15 mm to 0.3 mm.

(Heat-resistant release layer)
The release layer includes, for example, a heat resistant release material.
Examples of the heat-resistant release material include fluororubber and fluororesin (for example, polytetrafluoroethylene (PTFE), perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene hexafluoropropylene copolymer (FEP), etc.)) , Silicone resin, polyimide resin and the like.

  The thickness of the release layer is, for example, preferably from 10 μm to 50 μm, and preferably from 0.20 μm to 40 μm.

(Fixing belt manufacturing method)
There is no restriction | limiting in particular as a manufacturing method of the fixing belt which concerns on this embodiment, A well-known method is utilized.
Specifically, for example, first, a metal plate material is prepared, and the plate material is molded into a belt shape having a target thickness by a plastic working method to obtain a metal belt.
Examples of the plastic working method include a deep drawing method, a spatula drawing method, a pressing method, and a rotational plastic working method. An example of the rotational plastic working method is spinning.
In addition, you may heat-process a board | plate material before shape | molding a metal board | plate material.

Next, a heat resistant resin layer is formed on the inner peripheral surface of the metal belt. Examples of the method for forming the heat resistant resin layer include a centrifugal coating method, a spray coating method, and a flow coating method.
Next, a heat resistant elastic layer is formed on the outer peripheral surface of the metal belt as necessary. Examples of the method for forming the heat resistant elastic layer include a ring coating method, a dip coating method, and an injection molding method.
Then, a heat-resistant release layer is formed on the outer peripheral surface of the heat-resistant elastic layer. Examples of the method for forming the heat-resistant release layer include an electrostatic powder coating method, a spray coating method, a dip coating method, and a centrifugal coating method.
The order of forming the heat-resistant resin layer, the heat-resistant elastic layer, and the heat-resistant release layer is not particularly limited, and any of them may be first.

  Here, as an example of a method for forming a heat-resistant resin layer having at least an inner peripheral surface having a porous structure, for example, the following method is preferably exemplified.

(A) As a heat resistant resin layer, a polyimide precursor solution is applied to the inner peripheral surface of a metal belt to form a polyimide precursor coating film (hereinafter referred to as a “PI precursor coating film forming step”), and a polyimide precursor The surface of the body coating film is coated with a solvent displacement rate adjusting material having a large number of through holes, and the polyimide precursor coating film is brought into contact with the coagulation solvent to form a polyimide precursor coating film having a porous structure on the inner peripheral surface ( Hereinafter, the polyimide precursor coating film having a porous structure on the inner peripheral surface is thermally imidized to form a polyimide resin layer having a porous structure on the inner peripheral surface. (Hereinafter referred to as “PI resin layer forming step”) method (hereinafter, this method is referred to as the method (A)).
(B) A non-porous (hereinafter referred to as “bulk”) heat-resistant resin layer is formed on the inner peripheral surface of the metal belt as a heat-resistant resin layer using a heat-resistant resin coating solution (hereinafter referred to as “bulk-like”). A heat-resistant resin layer forming step), and a porous heat-resistant resin layer (hereinafter referred to as a “porous heat-resistant resin layer forming step”) using a heat-resistant resin coating solution containing a foaming agent on the surface of the bulk resin layer. (Referred to as method (B)).

Hereinafter, the method (A) will be described.
-PI precursor coating film formation process-
In the PI precursor coating film forming step, for example, a polyimide precursor coating film is formed by applying a polyimide precursor solution to the inner peripheral surface of the idle belt. Examples of the polyimide precursor used in the solution include polyamic acid obtained from a diamino compound and tetracarboxylic dianhydride. Examples of the solvent for dissolving the polyimide precursor include aprotic polar solvents such as N-methylpyrrolidone, N, N-dimethylacetamide, acetamide, and N, N-dimethylformamide.
Moreover, according to the objective, a lubricant, a plasticizer, electroconductive particle, antioxidant, and other additives may be added to the polyimide precursor solution.

A polyimide precursor solution is obtained by, for example, reacting an aromatic tetracarboxylic dianhydride and an aromatic diamine component in an organic polar solvent to synthesize a polyimide precursor.
The following are mentioned as a typical example of aromatic tetracarboxylic acid. For example, pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,3,4 , 4′-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2-bis ( 3,4-dicarboxyphenyl) ether dianhydrides, tetracarboxylic acid esters thereof, or mixtures of the above tetracarboxylic acids.
On the other hand, the aromatic diamine component is not particularly limited, and paraphenylenediamine, metaphenylenediamine, 4,4′-diaminodiphenyl ether, 4,4′-diaminophenylmethane, benzidine, 3,3′-dimethoxybenzidine, 4,4′-diaminodiphenylpropane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane and the like can be mentioned.

The amount of the polyimide precursor solution applied to the inner peripheral surface of the metal belt depends on the desired film thickness, but is preferably 200 g / m ² or more and 1800 g / m ² or less. If it is less than 200 g / cm ² , the film thickness may be insufficient. If it exceeds 1800 g / m ² , the film thickness may be excessive.

  The method for applying the polyimide precursor solution is not particularly limited. For example, the centrifugal molding application method described in JP-A-57-74131, the inner surface application method described in JP-A-62-19437, and JP-A-9 Examples thereof include a spiral coating method described in JP-A-85756.

-PI precursor precipitation process-
In the PI precursor deposition step, for example, when the polyimide precursor coating film is brought into contact with the coagulation solvent, a solvent substitution rate adjusting material having a large number of through holes is coated on the inner peripheral surface of the polyimide precursor coating film. This coagulation solvent is a solvent that is insoluble in the polyimide precursor and is compatible with the solvent of the polyimide precursor solution (aprotic polar solvent). For this reason, when the polyimide precursor coating film is brought into contact with a coagulation solvent, the solvent (proton polar solvent) exudes from the polyimide precursor coating film into the coagulation solvent, and the coagulation solvent penetrates instead. Since the polyimide precursor is insoluble in the coagulation solvent, the polyimide precursor is precipitated. When contacting the coagulation solvent, the surface of the polyimide precursor coating film is coated with a solvent replacement rate adjusting material, so that the coagulation solvent comes into contact with the polyimide precursor coating film only from the through hole of the adjusting material. Then, only in the contacted portion, the solvent (protonic polar solvent) oozes out into the coagulating solvent, and instead penetrates into the coagulating solvent, and in the polyimide precursor coating film, only the through hole portion of the adjusting material is fine. A hole is formed. For this reason, the polyimide precursor coating film which has a porous structure in an internal peripheral surface is formed. In addition, after forming the polyimide precursor coating film which has a porous structure on the surface, a solvent substitution rate adjusting material peels.

  The solvent substitution rate adjusting material may be any material as long as it has a structure that covers the surface of the polyimide precursor coating, but generally a sheet-like material is used. Specifically, examples of the solvent substitution rate adjusting material include nonwoven fabrics made of polyolefins such as polyethylene and polypropylene, cellulose, polyfluorinated ethylene fibers (for example, Teflon (registered trademark)), and porous membranes. . In addition, the solvent replacement rate adjusting material is provided with a large number of through-holes, and the number and size of the through-holes differ depending on the intended porous structure. The size (diameter) of the through hole is preferably set to be larger than the size of the continuous hole of the porous structure in the target polyimide resin layer.

  Examples of the coagulation solvent include water, alcohols (eg, methanol, ethanol, etc.), hydrocarbons (eg, hexane, heptane, etc.), ketones (eg, acetone, butanone, etc.), esters (eg, ethyl acetate, etc.). Water is the most convenient and preferable.

  As a method of bringing the polyimide precursor coating film into contact with the coagulation solvent, a method of immersing a metal belt having the polyimide precursor coating film formed on the inner peripheral surface in a tank filled with the coagulation solvent, and the like are suitable. In this method, the polyimide precursor coating film can be uniformly contacted with the coagulation solvent. In this dipping method, it is preferable to stir the coagulation solvent from the viewpoint of depositing the polyimide precursor more efficiently and forming a porous structure so that it can easily flow through the through-holes in the solvent substitution rate adjusting material.

  As another method for bringing the polyimide precursor coating film into contact with the coagulation solvent, the coagulation solvent may be allowed to flow down or sprayed onto the polyimide precursor coating film.

In the PI precursor deposition step, the elution amount of the aprotic polar solvent from the polyimide precursor coating varies depending on the time for which the polyimide precursor coating is brought into contact with the coagulation solvent. In other words, the size and depth (length) of the pores of the porous structure are controlled by this time.
In addition, since the elution amount of the aprotic polar solvent from the polyimide precursor coating film into the coagulation solvent usually increases as the temperature of the coagulation solvent increases, the size and depth of the continuous pores of the porous structure also depend on the temperature. Etc. are controlled.
Furthermore, since the amount of aprotic polar solvent eluted from the polyimide precursor coating can be adjusted by mixing the aprotic polar solvent with the coagulation solvent in advance, the porous structure can be adjusted accordingly. The size and depth of the pores are controlled.

-PI resin layer formation process-
In the PI resin layer forming step, first, drying is preferably performed for the purpose of removing the aprotic polar solvent. For example, the drying conditions may be 10 to 60 minutes at a temperature of 20 to 120 ° C. It is also effective to send warm air inside the metal belt. The drying temperature may be increased stepwise or at a constant rate.

  When drying is performed with the width direction of the metal belt being vertical (direction along the direction of gravity), streaks and unevenness may occur in a part of the coating film. In such a case, it is effective to further rotate the metal belt in the longitudinal direction. The rotation speed is preferably, for example, 10 rpm or more and 100 rpm or less, but depending on the rotating device, it may be faster or slower. Rotating the metal belt in the width direction is simpler in structure than the apparatus in which the metal belt is rotated in the width direction (the direction along the horizontal direction).

  In the PI resin layer forming step, after drying, for example, by heating the polyimide precursor coating film at a temperature of around 350 ° C. (desirably 300 ° C. or more and 450 ° C. or less) for 20 minutes or more and 60 minutes or less, a thermal imide And a polyimide resin layer is formed. During the thermal imidization treatment, if the solvent remains, the polyimide resin layer may be swollen. Therefore, the residual solvent is preferably removed before the thermal imidization treatment. It is preferable to heat and dry at a temperature of 200 ° C. or higher and 250 ° C. or lower for 10 minutes or more and 30 minutes or less prior to the crystallization treatment, and then the temperature is raised stepwise or at a constant rate to perform thermal imidization treatment Is good.

  Through the above steps, a polyimide resin layer (heat resistant resin layer) having a porous structure is formed at least on the inner peripheral surface.

  Hereinafter, the method (B) will be described. The method (B) will be described in accordance with a method of forming a polyimide resin layer using a polyimide precursor solution, but is not limited thereto.

-Bulk heat-resistant resin layer forming process-
In the bulk-like heat-resistant resin layer forming step, the bulk-like heat-resistant resin layer (polyimide resin layer) is the same as the above-described method (A) except that the solvent substitution rate adjusting material is not used in the PI deposition step. ). Here, “bulk shape” is a term for distinguishing from a resin layer having a porous structure, and means a heat-resistant resin layer having no porous structure. In some cases, the PI deposition step may not be performed.

-Porous resin layer formation process-
In the porous resin layer forming step, a foaming agent is added to the polyimide precursor solution in the method (A), and the solvent substitution rate adjusting material is not used in the polyimide precipitation step. Then, a bulk heat-resistant resin layer (polyimide resin layer) is formed. Thus, the porous heat-resistant resin layer is easily formed by heat-curing treatment (thermal imidization treatment) using a foaming agent together with the heat-resistant resin (polyimide precursor). In some cases, the PI deposition step may not be performed.

  Specific examples of the foaming agent include, for example, “Celmic C191 (manufactured by Sankyo Kasei Co., Ltd.)” (main component azodicarbonamide), “Celmic 417 (manufactured by Sankyo Kasei Co., Ltd.)” (inorganic), etc. Is mentioned.

  When the heat-resistant resin layer is composed of a plurality of layers as in the method (B), the lower heat-resistant resin layer is dried or semi-cured and heat-cured in the upper heat-resistant resin layer (thermal imidization) In addition to the treatment, it is also preferable to completely heat cure (thermal imidization treatment) the lower heat-resistant resin layer. By adopting such a method, the respective layers are melt-bonded and excellent adhesive strength is obtained, which is preferable.

(Application of fixing belt)
The fixing belt according to the present embodiment is applied to both a heating belt and a pressure belt, for example. In addition, as a heating belt, the heating belt which applies and heats the metal metal belt (or the metal layer which comprises it) which comprises a part of fixing belt as a metal layer heated by an electromagnetic induction system, Any of heating belts heated from an external heat source may be used.

[Fixing device]
The fixing device according to the present embodiment has various configurations, for example, a first rotating body, a second rotating body arranged in contact with the outer surface of the first rotating body, and an arrangement inside the first rotating body. And a pressing member that presses the first rotating body against the second rotating body from the inner peripheral surface of the first rotating body.
The fixing belt according to the present embodiment is applied as the first rotating body that is pressed from the inner peripheral surface to the second rotating body by the pressing member.

Hereinafter, as first and second embodiments, a fixing device including a heating belt to which a fixing belt according to this embodiment is applied and a pressure roll will be described.
The fixing device according to the present embodiment is not limited to the first and second embodiments, and includes a heating roll or a heating belt, and a pressure belt to which the fixing belt according to the present embodiment is applied. It may be.

(First Embodiment of Fixing Device)
The fixing device according to the first embodiment will be described. FIG. 2 is a schematic configuration diagram illustrating an example of a fixing device according to the first embodiment.

  As shown in FIG. 2, the fixing device 60 according to the first embodiment includes, for example, a heating belt 62 (an example of a first rotating body) and a pressure roller 64 (second rotation) that contacts the outer peripheral surface of the heating belt 62. An example of a body), a pressing pad 66 (an example of a pressing member) disposed at a position that contacts the inner peripheral surface of the heating belt 62 and opposes the pressing roller 64, and a support member 68 that supports the pressing pad 66; On the metal layer of the heating belt 62 (or the metal belt constituting a part of the fixing belt according to the present embodiment (or a part of the metal layer constituting the same)) in a state of non-contact with the outer peripheral surface side of the heating belt 62. An electromagnetic induction coil 70 (an example of a heating source) that generates an eddy current to generate heat on the outer peripheral surface of the heating belt 62 and a coil support member 72 that supports the electromagnetic induction coil 70 are provided.

  The pressure roller 64 is rotated in the direction of arrow R by a drive source (not shown). The heating belt 62 and the pressure roller 64 are in contact with each other so that the paper K (an example of a recording medium) is inserted, and the heating belt 62 is driven as the pressure roller 64 rotates in the arrow R direction. Rotate. A pressing pad 66 is disposed on the inner peripheral surface of the heating belt 62 so as to press the surface of the pressure roller 64 that is in contact with the outer peripheral surface of the heating belt 62, thereby forming a sandwiching region N. The pressing pad 66 is fixed by a support member 68 provided on the inner peripheral surface of the heating belt 62.

  On the other hand, the electromagnetic induction coil 70 is provided in a non-contact state on the outer peripheral surface side of the heating belt 62, and the electromagnetic induction coil 70 is fixed by a coil support member 72. The electromagnetic induction coil 70 is connected to a power source (not shown), and generates a magnetic field perpendicular to the outer peripheral surface of the heating belt 62 around the electromagnetic induction coil 70 when an alternating current is passed through the electromagnetic induction coil 70. The magnetic field fluctuates so as to generate an eddy current in the heat generating layer included in the heating belt 62 by an excitation circuit (not shown).

An image fixing operation by the fixing device 60 will be described.
As the pressure roller 64 rotates in the direction of arrow R, the heating belt 62 is driven to rotate in the direction of arrow S and is exposed to the magnetic field generated by the electromagnetic induction coil 70. At this time, an eddy current is generated in the heat generating layer included in the heating belt 62 around the electromagnetic induction coil 70, and the outer peripheral surface of the heating belt 62 is heated.

  The heating belt 62 heated in this way moves to the sandwiching area N with the pressure roller 64. On the other hand, a sheet K on which an unfixed toner image (not shown) is provided is conveyed in the direction of arrow P by a conveyance unit (not shown). When the sheet K passes through the sandwiching area N, an unfixed toner image (not shown) is heated by the heating belt 62 and is fixed on the surface of the sheet K to form a fixed image. The sheet K having the fixed image formed on the surface in this way is conveyed in the direction of arrow P by a conveying means (not shown). It is discharged from the fixing device 60.

  In addition, the heating belt 62 whose surface temperature on the outer peripheral surface has been lowered after the fixing process in the sandwiching region N is rotated in the direction of the electromagnetic induction coil 70 in order to be heated again in preparation for the next fixing process.

  The distance between the electromagnetic induction coil 70 and the heating belt 62 is not particularly limited, but from the viewpoint of increasing the coupling coefficient between the electromagnetic induction coil 70 and the metal layer of the heating belt 62 in order to increase the power factor. Is preferably set within 5 mm without contact.

(Second Embodiment of Fixing Device)
A fixing device according to the second embodiment will be described. FIG. 3 is a schematic configuration diagram illustrating an example of a fixing device according to the second embodiment.

  As shown in FIG. 3, the fixing device 80 according to the first embodiment, for example, presses the fixing belt module 86 including the heating belt 84 (an example of the first rotating body) and the heating belt 84 (the fixing belt module 86). And a pressurizing roll 88 (an example of a second rotating body) arranged. For example, a sandwiching region N (nip portion) where the heating belt 84 (fixing belt module 86) and the pressure roll 88 come into contact is formed. In the sandwiching area N, the sheet K (an example of a recording medium) is pressurized and heated to fix the toner image.

The fixing belt module 86 includes, for example, an endless heating belt 84 and a heating belt 84 wound around the pressure roll 88. The fixing belt module 86 is driven to rotate by a rotational force of a motor (not shown) and the heating belt 84 has an inner circumference. A heating and pressing roll 89 that is pressed from the surface toward the pressing roll 88 and a support roll 90 that supports the heating belt 84 from the inside at a position different from the heating and pressing roll 89 are provided.
The fixing belt module 86 is, for example, a support roll 92 that is disposed outside the heating belt 84 and defines a circulation path thereof, and a posture correction roll 94 that corrects the posture of the heating belt 84 from the heating pressure roll 89 to the support roll 90. And a support roll 98 for applying tension to the heating belt 84 from the inner peripheral surface on the downstream side of the sandwiching area N, which is an area where the heating belt 84 (fixing belt module 86) and the pressure roll 88 are in contact with each other. ing.

The fixing belt module 86 is provided, for example, such that a sheet-like sliding member 82 is interposed between the heating belt 84 and the heating press roll 89.
The sliding member 82 is provided, for example, so that its sliding surface is in contact with the inner peripheral surface of the heating belt 84, and is involved in holding and supplying oil existing between the sliding member 82 and the heating belt 84.
Here, the sliding member 82 is provided, for example, in a state in which both ends thereof are supported by the support member 96.

The heating and pressing roll 89 is a hard roll having a fluororesin film having a basis weight of 200 μm formed on the surface of the core metal as a protective layer for preventing metal wear on the surface of the cylindrical core metal made of aluminum.
Inside the heating and pressing roll 89, for example, a halogen heater 89A (an example of a heating source) is provided.

The support roll 90 is a cylindrical roll formed of aluminum, and a halogen heater 90A (an example of a heating source) is disposed therein, so that the heating belt 84 is heated from the inner peripheral surface side. Yes.
For example, spring members (not shown) that press the heating belt 84 outward are disposed at both ends of the support roll 90.

The support roll 92 is, for example, a cylindrical roll made of aluminum, and a release layer made of a fluororesin having a thickness of 20 μm is formed on the surface of the support roll 92.
The release layer of the support roll 92 is formed, for example, to prevent toner and paper powder from the outer peripheral surface of the heating belt 84 from accumulating on the support roll 92.
For example, a halogen heater 92A (an example of a heating source) is disposed inside the support roll 92, and the heating belt 84 is heated from the outer peripheral surface side.

  That is, for example, the heating belt 84 is heated by the heating press roll 89, the support roll 90, and the support roll 92.

The posture correction roll 94 is, for example, a cylindrical roll formed of aluminum, and an end position measuring mechanism (not shown) that measures the end position of the heating belt 84 is disposed in the vicinity of the posture correction roll 94. ing.
For example, the posture correcting roll 94 is provided with an axial displacement mechanism (not shown) that displaces the contact position in the axial direction of the heating belt 84 in accordance with the measurement result of the end position measuring mechanism. Configured to control.

  On the other hand, the pressure roll 88 has, for example, a cylindrical roll 88A made of aluminum as a base, and an elastic layer 88B made of silicone rubber and a release layer containing a fluororesin having a thickness of 100 μm are laminated in order from the base side. It has a configuration. The pressure roll 88 is rotatably supported, and is provided by being pressed against a portion where the heating belt 84 is wound around the heat pressing roll 89 by an urging means such as a spring (not shown). Thus, as the heating belt 84 (heating press roll 89) of the fixing belt module 86 rotates in the direction of arrow S, the pressing roll 88 is moved by the arrow R following the heating belt 84 (heating press roll 89). It is designed to rotate in the direction.

  Then, the sheet K having the unfixed toner image (not shown) is conveyed in the direction of the arrow P, and when guided to the sandwiching area N of the fixing device 80, it is fixed by the pressure and heat acting on the sandwiching area N. The

  In the fixing device 80 according to the second embodiment, the embodiment in which the halogen heater (halogen lamp) is applied as an example of the heating source has been described. However, the present invention is not limited to this. Etc.), resistance heating elements (heating elements that generate Joule heat by passing a current through the resistance: for example, a film having a thick film resistance formed on a ceramic substrate and fired) May be.

[Image forming apparatus]
Next, the image forming apparatus according to the present embodiment will be described.
The image forming apparatus of the present embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, a latent image forming unit that forms a latent image on the surface of the charged image carrier, and the latent image as a toner. Developing means for forming a toner image by developing, a transfer means for transferring the toner image to a recording medium, and a fixing means for fixing the toner image to the recording medium. The fixing device according to this embodiment is applied as the fixing unit.

The image forming apparatus according to the present embodiment will be described below with reference to the drawings.
FIG. 5 is a schematic configuration diagram showing the configuration of the image forming apparatus according to the present embodiment.

  As shown in FIG. 5, the image forming apparatus 100 according to the present embodiment is, for example, an intermediate transfer type image forming apparatus generally called a tandem type, and a plurality of toner images of each color component are formed by an electrophotographic system. Image forming units 1Y, 1M, 1C, and 1K, and a primary transfer unit 10 that sequentially transfers (primary transfer) the color component toner images formed by the image forming units 1Y, 1M, 1C, and 1K to the intermediate transfer belt 15. The secondary transfer unit 20 that collectively transfers (secondary transfer) the superimposed toner image transferred onto the intermediate transfer belt 15 onto the paper K that is a recording medium, and the fixing that fixes the secondary transferred image onto the paper K. Device 60. Further, the image forming apparatus 100 includes a control unit 40 that controls the operation of each device (each unit).

  This fixing device 60 is the fixing device 60 according to the first embodiment described above. Note that the image forming apparatus 100 may include the fixing device 80 according to the second embodiment described above.

  Each of the image forming units 1Y, 1M, 1C, and 1K of the image forming apparatus 100 includes a photoconductor 11 that rotates in the arrow A direction as an example of an image holding body that holds a toner image formed on the surface.

  A charger 12 for charging the photoconductor 11 is provided around the photoconductor 11 as an example of a charging unit, and a laser exposure device for writing an electrostatic latent image on the photoconductor 11 as an example of a latent image forming unit. 13 (the exposure beam is indicated by Bm in the figure) is provided.

  Further, around the photosensitive member 11, as an example of a developing unit, a developing device 14 that accommodates each color component toner and visualizes the electrostatic latent image on the photosensitive member 11 with the toner is provided. A primary transfer roll 16 for transferring the color component toner images formed thereon onto the intermediate transfer belt 15 by the primary transfer unit 10 is provided.

  Further, a photoconductor cleaner 17 for removing residual toner on the photoconductor 11 is provided around the photoconductor 11, and a charger 12, a laser exposure device 13, a developing device 14, a primary transfer roll 16, and a photoconductor cleaner. Seventeen electrophotographic devices are sequentially arranged along the rotation direction of the photoconductor 11. These image forming units 1Y, 1M, 1C, and 1K are arranged substantially linearly in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the upstream side of the intermediate transfer belt 15. Has been.

The intermediate transfer belt 15 as an intermediate transfer member is formed of a film-like pressure belt containing a resin such as polyimide or polyamide as a base layer and containing an appropriate amount of an antistatic agent such as carbon black. The volume resistivity is 10 ⁶ Ωcm or more and 10 ¹⁴ Ωcm or less, and the thickness is, for example, about 0.1 mm.

  The intermediate transfer belt 15 is circulated and driven (rotated) at a predetermined speed in the direction B shown in FIG. 5 by various rolls. As these various rolls, a drive roll 31 that is driven by a motor (not shown) having excellent constant speed to rotate the intermediate transfer belt 15, and an intermediate transfer belt that extends substantially linearly along the arrangement direction of the photoreceptors 11. 15, a support roll 32 that supports the intermediate transfer belt 15, a tension applying roll 33 that functions as a correction roll that applies a constant tension to the intermediate transfer belt 15 and prevents the intermediate transfer belt 15 from meandering, and a back roll provided in the secondary transfer unit 20. 25. A cleaning back roll 34 is provided in a cleaning unit that scrapes off residual toner on the intermediate transfer belt 15.

The primary transfer unit 10 includes a primary transfer roll 16 that is disposed to face the photoconductor 11 with the intermediate transfer belt 15 interposed therebetween. The primary transfer roll 16 includes a shaft and a sponge layer as an elastic layer fixed around the shaft. The shaft is a cylindrical bar made of metal such as iron or SUS. The sponge layer is a sponge-like cylindrical roll formed of a blend rubber of NBR, SBR, and EPDM containing a conductive agent such as carbon black and having a volume resistivity of 10 ^7.5 Ωcm or more and 10 ^8.5 Ωcm or less.

  The primary transfer roll 16 is placed in pressure contact with the photoreceptor 11 with the intermediate transfer belt 15 in between. Further, the primary transfer roll 16 has a voltage (primary polarity) opposite to the toner charging polarity (negative polarity; the same applies hereinafter). Transfer bias) is applied. As a result, the toner images on the respective photoconductors 11 are sequentially electrostatically attracted to the intermediate transfer belt 15 so that the superimposed toner images are formed on the intermediate transfer belt 15.

  The secondary transfer unit 20 includes a back roll 25 and a secondary transfer roll 22 disposed on the toner image holding surface side of the intermediate transfer belt 15.

The back roll 25 is made of a tube of EPDM and NBR blend rubber with carbon dispersed on the surface, and the inside is made of EPDM rubber. And it is formed so that the surface resistivity may be 10 ⁷ Ω / □ or more and 10 ¹⁰ Ω / □ or less, and the hardness is set to, for example, 70 ° (Asker C: manufactured by Kobunshi Keiki Co., Ltd., the same shall apply hereinafter). The The back roll 25 is disposed on the back side of the intermediate transfer belt 15 to constitute a counter electrode of the secondary transfer roll 22, and a metal power supply roll 26 to which a secondary transfer bias is stably applied is disposed in contact. ing.

On the other hand, the secondary transfer roll 22 includes a shaft and a sponge layer as an elastic layer fixed around the shaft. The shaft is a cylindrical bar made of metal such as iron or SUS. The sponge layer is a sponge-like cylindrical roll formed of a blend rubber of NBR, SBR, and EPDM containing a conductive agent such as carbon black and having a volume resistivity of 10 ^7.5 Ωcm or more and 10 ^8.5 Ωcm or less.

  The secondary transfer roll 22 is placed in pressure contact with the back roll 25 with the intermediate transfer belt 15 interposed therebetween. Further, the secondary transfer roll 22 is grounded and a secondary transfer bias is formed between the secondary transfer roll 22 and the back roll 25, and the secondary transfer roll 22 is grounded. The toner image is secondarily transferred onto the paper K conveyed to the transfer unit 20.

  Further, on the downstream side of the secondary transfer portion 20 of the intermediate transfer belt 15, an intermediate transfer belt that removes residual toner and paper dust on the intermediate transfer belt 15 after the secondary transfer and cleans the surface of the intermediate transfer belt 15. A cleaner 35 is provided so as to be able to contact and separate.

  The intermediate transfer belt 15, the primary transfer unit 10 (primary transfer roll 16), and the secondary transfer unit 20 (secondary transfer roll 22) correspond to an example of a transfer unit.

  On the other hand, on the upstream side of the yellow image forming unit 1Y, a reference sensor (home position sensor) 42 that generates a reference signal serving as a reference for taking image forming timings in the image forming units 1Y, 1M, 1C, and 1K. It is arranged. Further, an image density sensor 43 for adjusting image quality is disposed on the downstream side of the black image forming unit 1K. The reference sensor 42 recognizes a predetermined mark provided on the back side of the intermediate transfer belt 15 and generates a reference signal. Each image forming unit is instructed by an instruction from the control unit 40 based on the recognition of the reference signal. 1Y, 1M, 1C, and 1K are configured to start image formation.

  Further, in the image forming apparatus according to the present embodiment, as a transport unit that transports the paper K, the paper storage unit 50 that stores the paper K, and the paper K accumulated in the paper storage unit 50 is taken out and transported at a predetermined timing. A paper feed roll 51 that transports the paper K fed by the paper feed roll 51, a transport guide 53 that feeds the paper K transported by the transport roll 52 to the secondary transfer unit 20, and a secondary transfer roll 22. Are provided with a conveyance belt 55 for conveying the paper K conveyed after the secondary transfer to the fixing device 60, and a fixing entrance guide 56 for guiding the paper K to the fixing device 60.

Next, a basic image forming process of the image forming apparatus according to the present embodiment will be described.
In the image forming apparatus according to the present embodiment, image data output from an image reading device (not shown) or a personal computer (PC) (not shown) is subjected to predetermined image processing by an image processing device (not shown), and then image formation is performed. Image forming work is executed by the units 1Y, 1M, 1C, and 1K.

  The image processing apparatus performs predetermined image processing such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color editing, moving editing, and other various image editing on the input reflectance data. Is given. The image data that has been subjected to image processing is converted into color material gradation data of four colors Y, M, C, and K, and is output to the laser exposure unit 13.

  The laser exposure unit 13 irradiates each of the photoconductors 11 of the image forming units 1Y, 1M, 1C, and 1K with, for example, an exposure beam Bm emitted from a semiconductor laser in accordance with the input color material gradation data. . In each of the photoreceptors 11 of the image forming units 1Y, 1M, 1C, and 1K, the surface is charged by the charger 12, and then the surface is scanned and exposed by the laser exposure unit 13 to form an electrostatic latent image. The formed electrostatic latent images are developed as toner images of respective colors Y, M, C, and K by the respective image forming units 1Y, 1M, 1C, and 1K.

  The toner images formed on the photoconductors 11 of the image forming units 1Y, 1M, 1C, and 1K are transferred onto the intermediate transfer belt 15 in the primary transfer unit 10 where the photoconductors 11 and the intermediate transfer belt 15 are in contact with each other. The More specifically, in the primary transfer portion 10, a voltage (primary transfer bias) having a polarity opposite to the toner charging polarity (minus polarity) is applied to the base material of the intermediate transfer belt 15 by the primary transfer roll 16, and the toner image. Are sequentially superimposed on the surface of the intermediate transfer belt 15 to perform primary transfer.

  After the toner images are sequentially primary transferred onto the surface of the intermediate transfer belt 15, the intermediate transfer belt 15 moves and the toner image is conveyed to the secondary transfer unit 20. When the toner image is transported to the secondary transfer unit 20, the transport unit rotates the paper feed roll 51 in accordance with the timing at which the toner image is transported to the secondary transfer unit 20. Paper K is supplied. The paper K supplied by the paper feed roll 51 is transported by the transport roll 52, and reaches the secondary transfer unit 20 through the transport guide 53. Before reaching the secondary transfer unit 20, the sheet K is temporarily stopped, and the registration roll (not shown) rotates in accordance with the movement timing of the intermediate transfer belt 15 on which the toner image is held. And the position of the toner image are aligned.

  In the secondary transfer unit 20, the secondary transfer roll 22 is pressed against the back roll 25 via the intermediate transfer belt 15. At this time, the sheet K conveyed at the same timing is sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. At this time, when a voltage (secondary transfer bias) having the same polarity as the toner charging polarity (negative polarity) is applied from the power supply roll 26, a transfer electric field is formed between the secondary transfer roll 22 and the back roll 25. Is done. The unfixed toner image held on the intermediate transfer belt 15 is collectively electrostatically transferred onto the paper K in the secondary transfer unit 20 pressed by the secondary transfer roll 22 and the back roll 25. The

  Thereafter, the sheet K on which the toner image has been electrostatically transferred is conveyed as it is while being peeled off from the intermediate transfer belt 15 by the secondary transfer roll 22, and is conveyed downstream of the secondary transfer roll 22 in the sheet conveyance direction. It is conveyed to the belt 55. The transport belt 55 transports the paper K to the fixing device 60 in accordance with the optimal transport speed in the fixing device 60. The unfixed toner image on the paper K conveyed to the fixing device 60 is fixed on the paper K by receiving a fixing process with heat and pressure by the fixing device 60. Then, the sheet K on which the fixed image is formed is conveyed to a paper discharge container (not shown) provided in the discharge unit of the image forming apparatus.

  On the other hand, after the transfer to the paper K is completed, the residual toner remaining on the intermediate transfer belt 15 is conveyed to the cleaning unit as the intermediate transfer belt 15 rotates, and is cleaned by the cleaning back roll 34 and the intermediate transfer belt cleaner 35. It is removed from the intermediate transfer belt 15.

  Although the embodiments of the present invention have been described above, the present invention is not construed as being limited to the above-described embodiments, and various modifications, changes, and improvements can be made, and a range that satisfies the requirements of the present invention. Needless to say, this is feasible.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

[Example 1]
(Production of metal belt)
First, a stainless plate (SUS304 plate) was prepared.
Next, the stainless steel plate was heat-treated in a nitrogen atmosphere under the conditions of a processing temperature of 1100 ° C. and a processing time of 60 minutes.
Next, after forming a stainless steel plate into a cylindrical container shape by pressing and deep drawing, an inner diameter of 30 mm, a length of 370 mm, a wall thickness of 50 μm, and a surface roughness Ra of 1.7 μm by a rotational plastic working method. A tubular body was obtained. Specifically, a metal belt formed into a cylindrical container shape by pressing / deep drawing (processing cup press) is adjusted by spinning, and then cut at both ends to form an endless metal belt. Obtained.

(Formation of heat-resistant resin layer)
First, as a polyimide precursor solution, an N, N-dimethylacetamide solution of polyamic acid which is a polyimide precursor (trade name: U Varnish, Ube Industries, Ltd.) was prepared. The solid content concentration was adjusted to 20%, and the viscosity was adjusted to about 1 Pa · s.
Next, a polyimide precursor solution was applied to the inner peripheral surface of the metal belt by a centrifugal coating method to form a polyimide precursor coating film.
Next, the metal belt with the polyimide precursor coating film formed on the inner peripheral surface was placed in a drying furnace. The set temperature was initially 30 ° C., and the temperature was gradually increased so as to reach 100 ° C. after 1 hour. After this drying, the film became transparent. Further, the film was dried by heating at 150 ° C. for 20 minutes and 200 ° C. for 20 minutes to completely remove N, N-dimethylacetamide and water from the film.
Thereafter, the film was heated at 350 ° C. for 30 minutes to heat imidize the film. Thus, a polyimide resin layer was formed as a heat resistant resin layer on the entire inner peripheral surface of the metal belt. The film thickness of the polyimide resin layer was 3.0 μm.

(Formation of heat-resistant elastic layer)
Liquid silicone rubber (KE1940-35, liquid silicone rubber 35) adjusted so that the hardness specified by JIS type A is 35 ° on the outer peripheral surface of a metal belt having a polyimide precursor coating film formed on the inner peripheral surface. A product, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to a film thickness of 200 μm and dried to form a heat-resistant elastic layer.

(Formation of heat-resistant release layer)
By applying a PFA dispersion (perfluoroalkyl vinyl ether copolymer, 500CL, manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) to a film thickness of 30 μm on the outer peripheral surface of the heat-resistant elastic layer, and baking at 380 ° C., A heat-resistant release layer composed of PFA (perfluoroalkyl vinyl ether copolymer) was formed on the elastic layer composed of silicone rubber.

  Through the above steps, a fixing belt was produced.

[Examples 2 to 8]
A metal belt having a material type, thickness and inner surface roughness Ra according to Table 1 was prepared, and a heat-resistant resin layer having a material and thickness according to Table 1 was formed on the inner surface of the metal belt. A fixing belt was produced in the same manner as in Example 1 except for the above.
However, in Table 1, the formation of the heat-resistant resin layer indicated as “PAI” or “liquid crystal polymer” as a material was performed according to the following method.
In Table 1, the notation “Cu / SUS304” indicates that the metal belt has a laminated structure of a SUS304 layer (inner layer) and a Cu layer (outer layer).

(Formation of heat-resistant resin layer labeled as “PAI” as material)
First, a solvent-soluble polyamideimide solution (HPC-9000, manufactured by Hitachi Chemical Co., Ltd., solid content rate: 18%, solvent: n-methyl-2-pyrrolidone) was prepared.
Next, the polyamideimide solution was applied to the inner peripheral surface of the metal belt by a centrifugal coating method to form a polyamideimide coating film.
Next, with respect to the polyamide-imide coating film, drying is performed for 30 minutes at a temperature of 120 ° C. (primary drying treatment), and after the primary drying treatment, the temperature is raised stepwise by 200 ° C. for 30 minutes and 260 ° C. for 30 minutes. Then, a secondary drying process was performed.
In this manner, a polyamideimide layer having a target thickness was formed as a heat resistant resin layer on the inner peripheral surface of the metal belt.

(Formation of heat-resistant resin layer labeled as “Liquid Crystal Polymer” as material)
First, an infrared absorber (CI Pigment Violet 19) is added to a resin component of 100 parts by mass to a mixture obtained by heating and kneading 27 mol% of 6-hydroxy-2-naphthoic acid units and 73 mol% of p-hydroxybenzoic acid units. A thermotropic liquid crystal polymer was prepared by adding 10 parts by mass to pellets. The melting point of this liquid crystal polymer is 280 ° C.
Next, the metal belt is placed in a centrifugal molding apparatus, an appropriate amount of liquid crystal polymer pellets is put inside the metal belt, and is rotated at 300 rpm while being heated at 200 ° C. At this time, the pellets were heated by heating the metal belt and irradiating the pellets with light at an illuminance of 5 J / cm ² to generate heat in the blended infrared absorber.
Then, when the pellets were sufficiently melted and became a uniform layer on the inner peripheral surface of the metal belt by the centrifugal force generated by the rotation of the metal belt, the heating was stopped, and the mixture was cooled to room temperature (25 ° C.).
In this way, a liquid crystal polymer layer having a desired thickness was formed as a heat resistant resin layer on the inner peripheral surface of the metal belt.

[Examples 101 to 104]
A metal belt having a material type, thickness and inner surface roughness Ra according to Table 1 was prepared, and a heat-resistant resin layer having a material and thickness according to Table 1 was formed on the inner surface of the metal belt. A fixing belt was produced in the same manner as in Example 1 except for the above.
However, the heat resistant resin layer formed the heat resistant resin layer in which the internal peripheral surface has a porous structure according to the method shown below.
In addition, in formation of the heat resistant resin layer shown below, the solvent substitution rate adjusting material used in each Example was as follows.
Example 101: Solvent replacement rate modifier (trade name “Toyoflon” (air permeability 50 seconds / 100 cc: manufactured by Toray Industries, Inc.))
Example 102: Solvent replacement rate regulator (trade name “Toyoflon” (air permeability 30 seconds / 100 cc: manufactured by Toray Industries, Inc.))
Example 103: Solvent replacement rate regulator (trade name “Toyoflon” (air permeability 100 seconds / 100 cc: manufactured by Toray Industries, Inc.))
Example 104: Solvent replacement rate modifier (trade name “Toyoflon” (air permeability 70 seconds / 100 cc: manufactured by Toray Industries, Inc.))

(Forms a heat-resistant resin layer whose inner peripheral surface has a porous structure)
First, as a polyimide precursor solution, an N, N-dimethylacetamide solution of polyamic acid which is a polyimide precursor (trade name: U Varnish, Ube Industries, Ltd.) was prepared. The solid content concentration was adjusted to 20%, and the viscosity was adjusted to about 1 Pa · s.
Next, a polyimide precursor solution was applied to the inner peripheral surface of the metal belt by a centrifugal coating method to form a polyimide precursor coating film.
Next, the inner peripheral surface of the polyimide precursor coating film was coated with a solvent replacement speed adjusting material having many through holes, and then the metal belt was immersed in water and left for 1 minute. When the metal belt was pulled up, the polyimide precursor coating surface had a porous structure with a large number of continuous holes. And the water droplet on the surface of a metal belt and a polyimide precursor coating film was wiped off.
Next, the metal belt with the polyimide precursor coating film formed on the inner peripheral surface was placed in a drying furnace. The set temperature was initially 30 ° C., and the temperature was gradually increased so as to reach 100 ° C. after 1 hour. After this drying, the film became transparent. Further, the film was dried by heating at 150 ° C. for 20 minutes and 200 ° C. for 20 minutes to completely remove N, N-dimethylacetamide and water from the film.
Thereafter, the film was heated at 350 ° C. for 30 minutes to heat imidize the film.
In this way, a polyimide resin layer having a target thickness and a porous structure on the inner peripheral surface was formed as a heat resistant resin layer on the inner peripheral surface of the metal belt. In addition,
When the inner peripheral surface of the polyimide resin layer was observed, it was confirmed that the porous structure was composed of continuous pores.

[Comparative Examples 1-8]
Example 1 except that a metal belt having a material type, thickness, and surface roughness Ra of the inner peripheral surface according to Table 2 was prepared, and a heat resistant resin layer was not formed on the inner peripheral surface of the metal belt. In the same manner, a fixing belt was produced.

[Evaluation]
(Characteristic evaluation)
The surface roughness Ra of the inner peripheral surface (the inner peripheral surface of the heat resistant resin layer) of the fixing belt obtained in each example was examined by the method described above.
For the fixing belt in which the inner peripheral surface of the heat-resistant resin layer has a porous structure, the size of continuous pores of the porous structure (indicated as “continuous pore diameter” in the table) is also as described above. It investigated by the method.

(Actual machine evaluation)
The fixing belt obtained in each example as a heating belt was attached to a heating type fixing device according to Tables 1 and 2.
Next, the fixing device equipped with the fixing belt was incorporated into an image forming apparatus (manufactured by Fuji Xerox, modified Docu Print C620).
Then, the following evaluation was performed using this image forming apparatus. However, the fixing temperature of the fixing device (indicated as set temperature in the table) was set as shown in Tables 1 and 2.

-Fixation maintenance evaluation-
Using the image forming apparatus, the fixing maintenance property was evaluated as follows.
Specifically, using a Fuji Xerox test pattern, a copy test of 200,000 sheets was performed to confirm the fixability and evaluate the fixability.
As a result, in each example, good fixability was realized up to 200000 sheets. On the other hand, in each comparative example, fixing failure occurred on 50000 sheets, and the test was completed.

-Evaluation of sliding resistance of fixing belt-
Using the image forming apparatus, the sliding resistance of the fixing belt was evaluated as follows.
Specifically, when copying up to 200,000 sheets using Fuji Xerox test pattern, the driving torque (N · m) of the fixing belt is measured every 50000 sheets, and this is regarded as the sliding resistance of the fixing belt. evaluated.
The sliding resistance of the fixing belt is shown before copying (indicated as “initial” in the table) and after copying up to 200000 sheets (indicated as “after running” in the table).

  The details of each example and the evaluation results are listed in Tables 1 and 2 below.

  From the above results, it can be seen that, in this example, better results were obtained for both the fixing maintenance property and the sliding resistance than the comparative example.

60 fixing device 62 heating belt 64 pressure roller 66 pressing pad 68 support member 70 electromagnetic induction coil 72 coil support member 80 fixing device 82 sliding member 84 heating belt 86 fixing belt module 88 pressure roll 88A cylindrical roll 88B elastic layer 89A Halogen heater 89 Heating and pressing roll 90A Halogen heater 90 Support roll 92A Halogen heater 92 Support roll 94 Posture correction roll 96 Support member 98 Support roll 100 Image forming apparatus 110 Fixing member 110A Endless belt 110B made of metal Heat resistant resin layer 110C Heat resistant elasticity Layer 110D Heat-resistant release layer

Claims (5)

A metal endless belt,
A heat-resistant resin layer provided on the inner peripheral surface of the endless belt and configured to include a heat-resistant resin;
Have
At least the inner peripheral surface of the heat resistant resin layer is composed of a porous structure having continuous pores,
A fixing member having a size of continuous pores of the porous structure and a size of continuous pores existing on an inner peripheral surface of the heat resistant resin layer is 1.0 μm or more and 100 μm or less.   The fixing member according to claim 1, wherein the heat-resistant resin layer has a thickness of 0.5 μm to 10 μm.   The fixing member according to claim 1, wherein a surface roughness Ra of an inner peripheral surface of the heat resistant resin layer is 0.1 μm or more and 3.0 μm or less. A first rotating body constituted by the fixing member according to claim 1;
A second rotating body disposed in contact with the outer surface of the first rotating body;
A pressing member that is disposed inside the first rotating body and presses the first rotating body against the second rotating body from an inner peripheral surface of the first rotating body;
A fixing device. An image carrier,
Charging means for charging the surface of the image carrier;
Latent image forming means for forming a latent image on the surface of the charged image carrier;
Developing means for developing the latent image with toner to form a toner image;
Transfer means for transferring the toner image to a recording medium;
Fixing means for fixing the toner image to the recording medium, the fixing means being the fixing device according to claim 4;
An image forming apparatus comprising:

Images