JP6361136B2 - Fixing belt, fixing device, and image forming apparatus - Google Patents

Description

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

  In an image forming apparatus using powdery toner, a toner image is formed by selectively transferring toner to a latent image formed on an image holding member due to a difference in electrostatic potential. After electrostatically transferring the toner image directly onto the recording medium, or after primary transfer to the intermediate transfer body and then secondary transfer to the recording medium, the recording medium is placed between the fixing member and the pressure member. The toner image is sandwiched and heated and pressed to be fixed on the recording medium.

  As a fixing device, for example, in Patent Document 1, a rotatable heat fixing roll having a heating source, an endless belt that is in pressure contact with the heat fixing roll and driven with the heat roll, and an inner side of the endless belt are disposed. And a pressing member that presses the endless belt against the heating roll and forms a pressure contact area (nip portion) between the endless belt and the heat fixing roll, and is fitted inside the both ends of the endless belt. And a belt guide member that rotatably guides the inner surface of the endless belt. By passing the sheet through the contact area, the unfixed toner image on the sheet is heated and pressure-fixed. A fixing device is disclosed.

For example, the following endless belts for fixing are known.
For example, Patent Document 2 discloses a polyimide tubular material comprising a polyimide resin base material, a primer layer on the surface thereof, and a fluororesin layer on the surface thereof. The resin contains an inorganic semiconductive material (for example, titanium oxide), or a highly conductive material (for example, carbon black) and an inorganic semiconductive material (for example, titanium oxide). A fixing belt having a thickness of 7 μm or less is disclosed.

  For example, Patent Document 3 discloses that a fluororesin on a base material, particularly a fluororesin having a melting point of 320 ° C. or lower, and a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer resin having a heat resistant resin having an average particle size of 10 μm or less. In particular, there is disclosed a fixing belt having a release layer formed by blending an aromatic polyimide resin powder, an aromatic polyimide resin obtained from an aromatic polyimide precursor, or an aromatic polyamide resin powder.

  For example, in Patent Document 4, a fluororesin layer is provided on the surface of a base material composed of a polyimide resin tubular material via a primer layer as an adhesion reinforcing layer, and an average particle diameter is included in the fluororesin layer. Discloses a fixing belt in which an inorganic particulate material having a particle size of 5 μm to 25 μm and a conductive material are blended.

Japanese Patent No. 3298354 JP 2001-125404 A Japanese Patent Laid-Open No. 2003-12885 JP 2005-258432 A

  An object of the present invention is to provide a fixing belt in which exposure of a base material layer due to local abrasion of a surface layer is suppressed.

In order to achieve the above object, the following invention is provided.
Invention of Claim 1 is provided on the outer peripheral surface of a base material layer, the said base material layer, The surface layer containing the 1st particle | grains whose hardness is higher than fluorine-containing resin and the said fluorine-containing resin, The said fluorine-containing And a second particle that is an inorganic material having a hardness higher than that of the resin and partially embedded in the outer peripheral surface of the base material layer.

  The invention according to claim 2 is the fixing belt according to claim 1, wherein an average particle diameter of the second particles is larger than an average particle diameter of the first particles.

  According to a third aspect of the present invention, in the fixing according to the first or second aspect, the ratio of the total area of the exposed portion of the second particles in the outer peripheral surface of the base material layer is 5% or more and 25% or less. It is a belt.

  According to a fourth aspect of the present invention, the first rotating body that is rotationally driven, the first rotating body and the outer peripheral surface of each of the first rotating body are in contact with each other, and the first rotating body rotates in accordance with the rotation of the first rotating body. A second rotating body including the fixing belt according to any one of claims 1 to 3 and a recording medium having an unfixed toner image in contact with the first rotating body and the second rotating body. And a heating unit that heats an unfixed toner image on the recording medium via the first rotating body when passing through the region to be processed.

  According to a fifth aspect of the present invention, there is provided an image carrier, a charging unit for charging the surface of the image carrier, and electrostatic latent image formation for forming an electrostatic latent image on the surface of the image carrier charged by the charging unit. Developing means for developing the electrostatic latent image formed on the surface of the image carrier with a developer containing toner to form a toner image; and the toner image formed on the surface of the image carrier. An image forming apparatus comprising: transfer means for transferring the toner image to a recording medium; and fixing means including the fixing device according to claim 4 for fixing the toner image transferred to the recording medium to the recording medium.

  According to the invention of claim 1, the substrate particles are exposed by local abrasion of the surface layer as compared with the case where the second particles adhere to the outer peripheral surface of the substrate layer or are not partially embedded. There is provided a fixing belt in which the toner is suppressed.

  According to the invention of claim 2, exposure of the base material layer due to local wear of the surface layer is suppressed as compared with the case where the average particle size of the second particles is equal to or less than the average particle size of the first particles. A fuser belt is provided.

  According to invention of Claim 3, exposure of the base material layer by local abrasion of a surface layer is suppressed compared with the case where the total area which the said 2nd particle accounts in the outer peripheral surface of the said base material layer is less than 5%. Thus, there is provided a fixing belt in which a secondary failure such as an image defect due to insufficient toner releasability due to an increase in the area occupied by the second particles is suppressed as compared with the case where it exceeds 25%.

  According to the invention of claim 4, the surface layer of the fixing belt is locally compared with the case where a fixing belt in which the second particles adhere to the outer peripheral surface of the base material layer or a part of which is not embedded is applied. A fixing device is provided in which the occurrence of poor fixing due to wear of the base material layer due to wear is suppressed.

  According to the invention of claim 5, the surface of the fixing belt is provided as compared with a case where a fixing device using a fixing belt to which the second particles adhere to the outer peripheral surface of the base material layer or a part of which is not embedded is provided. Provided is an image forming apparatus in which a layer is locally worn and occurrence of fixing failure due to exposure of a base material layer is suppressed.

FIG. 4 is a schematic diagram illustrating a part of a cross section in the thickness direction of the fixing belt according to the exemplary embodiment. FIG. 4 is a schematic diagram illustrating a part of a cross section in a thickness direction when a surface layer of the fixing belt according to the exemplary embodiment is locally worn. 1 is a schematic diagram illustrating an example of a configuration of an image forming apparatus according to an exemplary embodiment. 1 is a schematic diagram illustrating an example of a configuration of a fixing device according to an exemplary embodiment. FIG. 3 is a schematic diagram illustrating a structure of a fixing belt (pressure belt) side of the fixing device according to the present embodiment. FIG. 6 is a diagram illustrating a distribution of wear amount of a surface layer of a fixing belt in Examples and Comparative Examples. FIG. 6 is a schematic view showing a part of a cross section in the thickness direction of a conventional fixing belt.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are used for explaining the present embodiment and do not represent the actual size.

<Fixing belt>
The fixing belt according to this embodiment includes a base material layer, a surface layer that is provided on the outer peripheral surface of the base material layer, and includes a fluorine-containing resin and first particles having a hardness higher than that of the fluorine-containing resin, The second particles have higher hardness than the fluorine-containing resin and are bonded to the outer peripheral surface of the base material layer or partially embedded.

  FIG. 1 schematically shows a part of a cross section in the thickness direction of an example of a fixing belt according to this embodiment. The fixing belt according to the present embodiment is a tubular (cylindrical) endless belt, and the fixing belt 62 shown in FIG. 1 is formed by bonding the base material layer 5 and the surface layer 3 disposed on the base material layer 5. Configured. In the surface layer 3, first particles 4 having higher hardness than the fluorine-containing resin 2 are dispersed in the fluorine-containing resin 2. On the other hand, the second particles 6 having higher hardness than the fluorine-containing resin contained in the surface layer 3 are dispersed on the outer peripheral surface of the base material layer 5 in a state where a part of each particle 6 is embedded. Here, the second particle 6 is partially embedded in the outer peripheral surface of the base material layer 5, and a part of the second particle 6 is embedded in the surface layer portion constituting the outer peripheral surface of the base material layer 5. It means that the remaining portion is fixed in a state protruding from the outer peripheral surface of the base material layer 5.

A fixing belt for fixing an unfixed toner image on a recording medium usually has a surface layer having a good releasability laminated on a base material layer. The surface layer 3 includes a fluorine-containing resin 2 and a filler (filler) 104 as shown in FIG. 7 in order to ensure mechanical strength and improve slipperiness with respect to a recording medium such as paper. . However, in the fixing belt, a portion through which an edge of a recording medium such as paper passes is likely to be locally worn, and when the base material layer 5 is exposed, image defects due to toner sticking or the like are likely to occur.
On the other hand, in the fixing belt 62 according to the present embodiment, the first particles 4 having wear resistance are dispersed in the surface layer 3, and the second particles 6 having wear resistance are the base material layer. 5 is present at the interface with the surface layer 3 in a state of being bonded or partially embedded in the outer peripheral surface of the particle 5, so that the particle 6 having wear resistance even if the surface layer 3 is locally worn as shown in FIG. It is considered that the exposure of the base material layer 5 due to local wear of the fixing belt 62 is suppressed.

(Surface layer)
The surface layer 3 is a layer constituting the outer peripheral surface (contact surface with the recording medium) of the fixing belt 62 according to the present embodiment, and includes the fluorine-containing resin 2 and the first particles 4 that are harder than the fluorine-containing resin 2. It is configured to include.

-Fluorine-containing resin-
The fluorine-containing resin 2 is suitable in that it has heat resistance and is excellent in releasability from toner.
Examples of the fluorine-containing resin contained in the surface layer 3 include tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-perfluoromethyl vinyl ether copolymer (MFA), and tetrafluoroethylene-perfluoro. Ethyl vinyl ether copolymer (EFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyethylene-tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoride And ethylene fluoride (PCTFE), vinyl fluoride (PVF), and the like. Among these, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-perfluoromethyl vinyl ether copolymer (MFA), tetrafluoroethylene-perfluoroethyl, among others. A vinyl ether copolymer (EFA) or a modified product thereof is preferable in terms of heat resistance, mechanical properties, and the like.
These fluorine-containing resins are used alone or in combination of two or more. The molecular weight of the fluorine-containing resin is not particularly limited.

-First particle-
The surface layer 3 includes first particles 4 having a higher hardness than the fluorine-containing resin 2. By including the first particles 4 having higher hardness than the fluorine-containing resin 2 contained in the surface layer 3, the wear resistance and the slipperiness with respect to the recording medium such as paper are improved.

The size of the first particles 4 contained in the surface layer 3 is preferably in the range of 1 μm to 10 μm in average particle size, and more preferably in the range of 2 μm to 8 μm.
The shape of the 1st particle | grains 4 is not specifically limited, Particle | grains, such as an indefinite shape, flake shape, needle shape, and fibrous shape, are used. Among these, amorphous particles are more desirable.

Examples of the first particles 4 included in the surface layer 3 include a powder containing an inorganic material (inorganic material powder), a heat resistant resin powder, and the like.
The inorganic material powder is selected from known inorganic material powders. Specifically, lubricating fillers having a layered structure such as molybdenum disulfide, hexagonal boron nitride, mica, graphite, talc, graphite, etc .; aluminum oxide, titanium oxide, iron oxide, silicon oxide, cerium oxide, composite metal oxide Metal oxides such as silicon carbide; carbides such as silicon carbide and boron carbide; nitrides such as cubic boron nitride and silicon nitride; and glass powder, aluminum silicate, aluminum borate, metal powder, carbon fiber, potassium titanate, Examples thereof include barium sulfate and silicate compounds.

  Examples of the heat resistant resin of the heat resistant resin powder include (fluorinated) polyimide, polyamideimide, polybenzimidazole, wholly aromatic polyester resin, modified PTFE, and cross-linked PTFE.

Further, a powder obtained by microencapsulating an inorganic filler in a heat resistant resin may be used.
Moreover, in order to improve adhesiveness with the fluorine-containing resin contained in the surface layer, a filler surface-treated with a fluorine-based coupling agent may be used.

-Other additives-
In addition to the first particles 4, the surface layer 3 may contain other additives such as a conductive agent.
The conductive agent that can be included in the surface layer 3 is not particularly limited as long as the surface resistivity is adjusted depending on the blending amount thereof, and examples thereof include the following electron conductive conductive agents and ion conductive conductive agents.
Examples of the electron conductive conductive agent include carbon black, graphite, aluminum, nickel, copper alloy and other metals or alloys; tin oxide, zinc oxide, potassium titanate, tin oxide-indium oxide, and tin oxide-antimony oxide composite oxide. And metal oxides such as
Examples of the ion conductive conductive agent include sulfonates, ammonia salts, and various surfactants such as cationic, anionic, and nonionic surfactants.

  The thickness of the surface layer is usually 5 μm or more and 100 μm or less, preferably 10 μm or more and 50 μm or less, in order to ensure the long life of the belt, mechanical strength, flexibility and wear durability.

(Base material layer)
The base material layer 5 is a layer that supports the surface layer 3 and constitutes the inner peripheral surface of the fixing belt 62.
The base material layer 5 is made of a material having mechanical strength, flexibility, and the like as the fixing belt 62, and is selected from various known resin materials, metal materials, and the like.

As a resin material that can form the base material layer 5, a resin called engineering plastic is generally suitable.
Engineering plastics constituting the base material layer include, for example, fluororesin, polyimide (PI, thermosetting polyimide, thermoplastic polyimide), fluorinated polyimide, polyamideimide (PAI), polybenzimidazole (PBI), and polyether ether. Examples include ketone (PEEK), polysulfone (PSU), polyethersulfone (PES), polyphenylene sulfide (PPS), polyetherimide (PEI), wholly aromatic polyester (liquid crystal polymer), and the like. Among these, polyimide, fluorinated polyimide, polyamideimide, polyetherimide, and the like are preferable because they are excellent in mechanical strength, heat resistance, wear resistance, chemical resistance, and the like.

As a metal material which can comprise the base material layer 5, various metals, such as SUS, nickel, copper, aluminum, are mentioned, for example.
In addition, it is good also as a base material layer by laminating | stacking the resin material and metal material which were mentioned above.

  In order to have mechanical strength as the fixing belt 62 and to ensure flexibility, the thickness of the base material layer 5 is usually 20 μm or more and 150 μm or less, and desirably 40 μm or more and 100 μm or less.

(Second particle)
On the outer peripheral surface of the base material layer 5, the second particles 6 having higher hardness than the fluorine-containing resin 2 contained in the surface layer 3 are adhered, or a part of each particle 6 is embedded and dispersed. .

  Examples of the second particles 6 that are bonded or partially embedded in the outer peripheral surface of the base material layer 5 (hereinafter, may be referred to as “second particles fixed to the outer peripheral surface of the base material layer”) are, for example. The same kind of particles as the first particles 4 included in the surface layer 3 are used. That is, it is preferable that the second particles 6 have higher hardness and higher wear resistance than the fluorine-containing resin contained in the surface layer 3 like the first particles 4 contained in the surface layer 3. For example, a lubricious filler having a layered structure such as molybdenum disulfide, hexagonal boron nitride, mica, graphite, talc, graphite; aluminum oxide, titanium oxide, iron oxide, silicon oxide, cerium oxide, composite metal oxide, etc. Metal oxides; carbides such as silicon carbide and boron carbide; nitrides such as cubic boron nitride and silicon nitride; and glass powder, aluminum silicate, aluminum borate, metal powder, carbon fiber, potassium titanate, barium sulfate, A silicate compound etc. are mentioned.

  The second particles 6 fixed to the outer peripheral surface of the base material layer 5 are not limited to the inorganic material, and may be a resin powder having heat resistance. Examples of the resin that can form the second particles 6 include polyimide, polyamideimide, polybenzimidazole, wholly aromatic polyester resin, and the like.

The size of the second particles 6 fixed to the outer peripheral surface of the base material layer 5 is preferably in the range of 1 μm to 10 μm in average particle size, and more preferably in the range of 2 μm to 8 μm.
The shape of the 2nd particle | grains 6 is not specifically limited, Particle | grains, such as an indefinite shape, flake shape, needle shape, and fiber shape, are used. Among these, amorphous particles are more desirable.

  Examples of the method of bringing the second particle 6 into a state where the second particle 6 is adhered to the outer peripheral surface of the base material layer 5 or a state where a part of the particle 6 is embedded are, for example, a part of the second particle 6 being the outer peripheral surface of the base material layer 5. A method in which the surface layer 3 is directly laminated thereon after being formed so as to be directly embedded in and fixed to the substrate, and the adhesion between the resin material constituting the base layer 5 and the fluorine-containing resin constituting the surface layer 3 A heat-resistant adhesive of a material different from the resin material of the base material layer 5 is applied as a thin layer on the base material layer 5 so that a part of the second particles are embedded in the adhesive layer and the rest The surface layer 3 may be laminated after the portion is fixed in a state of protruding from the adhesive layer.

In addition, when fixing the 2nd particle | grains 6 using an adhesive agent on the outer peripheral surface of the base material layer 5, the material of the surface of the base material layer 5 may be a metal.
The adhesive layer is generally called a primer, and acts as an adhesive by heating and baking the surface layer including a heat-resistant resin or metal base layer and a fluorine-containing resin, and the base layer 5 and the surface layer 3 It is desirable to have a strong bond.

  The adhesive layer does not necessarily have to be heat-adhesive to the fluorine-containing resin, but when the adhesiveness between the base material layer 5 and the fluorine-containing resin 2 contained in the surface layer 3 is insufficient. Is formed such that a part of the second particle 6 is directly embedded and fixed to the outer peripheral surface of the base material layer 5 with respect to the base material layer 5, and then a primer is placed on the second particle 6. It is preferable to apply the film so as not to be buried.

  The material of the second particles 6 is preferably the same type of material as that of the first particles 4 included in the surface layer 3, but may be particles of a different material.

  The size of the second particles 6 may be the same as the size of the first particles 4 included in the surface layer 3, but a part of the second particles 6 is the outer peripheral surface of the base material layer 5. It is more preferable that the second particles 6 have a larger average particle size than the first particles 4 dispersed in the surface layer 3. The average particle size of the particles 4 and 6 is measured by a laser diffraction / scattering particle size distribution measuring device.

  The distribution density of the second particles 6 protruding in a convex manner on the outer peripheral surface of the base material layer 5 is such that the first particles dispersed in the surface layer 3 when the surface layer 3 laminated thereon is worn. It is desirable that the distribution density is the same as the distribution density at which 4 is exposed. Specifically, the ratio of the total area area (distribution density) of the exposed portion of the second particles 6 on the outer peripheral surface of the base material layer 5 is preferably in the range of 5% to 25%, and 10% or more. A range of 20% or less is more preferable. The distribution density of the second particles 6 on the outer peripheral surface of the base material layer 5 is obtained by observing with a digital optical microscope (digital microscope).

  In addition, from the viewpoint of improving wear resistance, it is exposed on the outer peripheral surface of the base material layer as compared with the distribution density of the first particles exposed at the time of wear from the outer peripheral surface of the surface layer within a range that does not impair the releasability to the toner. It is more preferable to increase the dispersion density of the second particles in the range of 5% to 10%.

  In addition to the surface layer of the fixing belt (base layer or adhesive layer), various additives are added depending on the purpose of conductivity, thermal conductivity, insulation, peelability, slidability, reinforcement, etc. May be. Examples of the various additives include additives added to the surface layer.

The fixing belt according to the present embodiment has a two-layer structure in which a surface layer containing a fluorine-containing resin and first particles is mainly laminated on a base material layer, but is not limited to a two-layer structure. An adhesive layer or other layer may be disposed between the layer and the surface layer.
Further, the fixing belt according to this embodiment is not particularly limited in shape, size, and the like.

(Fixing belt manufacturing method)
The method for manufacturing the fixing belt according to the present embodiment is not particularly limited, but for example, it is preferably manufactured by the following method.

-First manufacturing method-
First, a mold release agent is baked on the surface of a metal cylindrical tube as a mold, and then the N-methylpyrrolidone (NMP) dispersion solution (polyimide varnish) of a polyimide precursor is flow-coated (spiral winding coating) on the mold. Then, the coating liquid film containing the polyimide precursor is smoothed while being dried while rotating the mold, and a polyimide precursor coating film in a semi-dried state is obtained.

  Next, a dispersion solution in which filler particles (second particles) are dispersed in a solution obtained by further diluting the polyimide precursor solution (N-methylpyrrolidone dispersion solution) used for forming the semi-dried coating film with NMP. On the semi-dried polyimide precursor coating film (semi-dried film), overcoating is performed by a coating method such as flow coating or spray coating in the same manner as described above. Furthermore, it heat-drys in a rotation state, and the base material layer which the filler particle disperse | distributed in the state embedded to the base material layer partially on the surface of a base material layer is formed.

  Instead of applying the dispersion solution in which the filler particles are dispersed in the polyimide precursor solution, for example, after spraying the filler particles on the surface of the semi-dry film by a dry method, the particles are further pressed to coat a part of the particles. The base material layer may be formed by being buried in the surface.

  Next, a surface layer containing a fluorine-containing resin and filler particles (first particles) is formed on the base material layer dispersed in a state where a part of the filler particles are embedded in the surface of the base material layer. A coating solution for forming a surface layer containing a fluorine-containing resin and filler particles is applied onto the base material layer by a known coating method such as dip coating or spray coating. Furthermore, the endless belt according to the present embodiment is manufactured by performing drying and baking.

-Second manufacturing method-
After forming the polyimide base material, the filler particles (second particles) may be adhered to the polyimide base material with an adhesive, and then the surface layer may be formed.

  Specifically, an N-methylpyrrolidone dispersion solution of a polyimide precursor (polyimide varnish) is applied to the surface of a mold similar to that in the first manufacturing method, and further dried and baked to once form a belt-like polyimide base. A material film is produced.

After preparing the polyimide base material, the polyimide solution is prepared by dispersing filler particles (second particles) in the primer solution using the primer solution as an adhesive in order to ensure adhesion between the polyimide and the fluorine-containing resin on the base material. A base material layer is formed which is applied on a base material and dispersed in a state where a part of the filler particles are adhered to the surface of the polyimide base material.
Usually, after the primer layer has a thickness of several μm or less and the dispersion solution is applied and dried to evaporate the solvent, a part of the filler particles are buried in the primer layer, and the remaining part is on the surface of the polyimide substrate. It will be in the state which protruded in convex shape.

  A coating solution for forming a surface layer containing a fluorine-containing resin and filler particles (second particles) on the base material dispersed in a state where the filler particles are adhered to the surface of the polyimide base material as described above is a dip coating method. The fixing belt according to the present embodiment is manufactured by coating by a known coating method such as a spray coating method, followed by drying and baking.

<Image forming apparatus>
Next, an image forming apparatus to which the fixing belt according to the present embodiment is applied will be described.
The image forming apparatus to which the fixing belt according to the present embodiment is applied is not particularly limited as long as it fixes an unfixed toner image on a recording medium by applying heat and pressure. The fixing belt according to this embodiment is particularly preferably used as a pressure member (pressure belt).
Here, an intermediate transfer type image forming apparatus generally called a tandem type will be described as an example.

  As shown in FIG. 3, the image forming apparatus 100 according to the present embodiment includes a plurality of image forming units 1Y, 1M, 1C, and 1K that form toner images of respective color components by an electrophotographic method as an image forming unit. Further, as a transfer unit, a primary transfer unit 10 that sequentially transfers (primary transfer) toner images of each color component formed on the surface of each image carrier 11 by the image forming units 1Y, 1M, 1C, and 1K to the intermediate transfer belt 15. And a secondary transfer section 20 that collectively transfers (secondary transfer) the overlapping toner images transferred onto the intermediate transfer belt onto the paper P as a recording medium. Further, the image forming apparatus includes a fixing device 60 that fixes the secondary transferred image on the paper P as a fixing unit. Moreover, it has the control part 40 which controls operation | movement of each apparatus (each part).

  Each of the image forming units 1Y, 1M, 1C, and 1K includes an image carrier (photosensitive drum) 11 that rotates in the direction of arrow A, a charger 12 that charges the photosensitive drum 11, and an electrostatic image on the photosensitive drum 11. A laser exposure unit 13 that forms a latent image and a developing unit 14 that stores toner of each color component and visualizes the electrostatic latent image on the photosensitive drum 11 with the toner to form a toner image. In addition, a primary transfer roll 16 that transfers a toner image of each color component formed on the photosensitive drum 11 to the intermediate transfer belt 15 in the primary transfer unit 10, and a foreign matter removing member that removes residual toner on the photosensitive drum 11 ( Drum cleaner) 17. 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. ing.

  The intermediate transfer belt 15 is circulated and driven in the direction of arrow B shown in FIG. As various rolls, a drive roll 31 that drives the intermediate transfer belt 15, a support roll 32 that supports the intermediate transfer belt 15, a tension roll 33 that applies a certain tension to the intermediate transfer belt 15 and prevents meandering, a secondary roll A back roll 25 provided in the transfer unit 20 and a cleaning unit back roll 34 provided in a cleaning unit that scrapes residual toner on the intermediate transfer belt 15 are provided.

  The primary transfer unit 10 includes a primary transfer roll 16 that faces the photosensitive drum 11 with the intermediate transfer belt 15 interposed therebetween. The secondary transfer unit 20 includes a secondary transfer roll (transfer member) 22 disposed on the side of the intermediate transfer belt 15 that holds the toner image, and a back surface of the intermediate transfer belt 15 as a counter electrode of the secondary transfer roll 22. A back roll 25 disposed on the side, and a power supply roll 26 that applies a secondary transfer bias to the back roll 25.

  An intermediate transfer belt cleaner 35 for removing residual toner and paper dust on the intermediate transfer belt 15 is disposed downstream of the secondary transfer unit 20. A reference sensor (home position sensor) 42 that generates a reference signal for timing image formation in each of the image forming units 1Y, 1M, 1C, and 1K is disposed upstream of the yellow image forming unit 1Y. . An image density sensor 43 for adjusting image quality is disposed on the downstream side of the black image forming unit 1K.

  The paper transport system includes a paper storage unit 50, a pick-up roll 51 that takes out and transports the paper (P) in the paper storage unit 50, a transport roll 52 that transports the paper P, and the secondary transfer unit 20. A conveyance base 53 that conveys the paper P secondarily transferred by the secondary transfer roll 22 to the fixing device 60, and a fixing inlet guide 56 that guides the paper P to the fixing device 60.

Next, a basic process of the image forming apparatus 100 according to the present embodiment will be described.
In the image forming apparatus 100 according to the present embodiment, after image processing is performed on image data output from an image reading device (not shown) or the like, four color materials of Y, M, C, and K are used as the image data. It is converted into gradation data and output to the laser exposure unit 13. For example, each of the photosensitive drums that rotates the exposure beam Bm emitted from the semiconductor laser in the direction of arrow A of the image forming units 1Y, 1M, 1C, and 1K according to the input color material gradation data. 11 is irradiated. After the surface of each photosensitive drum 11 is charged by a charger, the surface is scanned and exposed by a 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.

Next, the toner image formed on the photosensitive drum 11 is sequentially superposed on the surface of the intermediate transfer belt 15 in the primary transfer unit 10 to perform primary transfer. The intermediate transfer belt 15 moves in the direction of arrow B and conveys the toner image to the secondary transfer unit 20. The paper transport system supplies the paper P from the paper storage unit 50 in synchronization with the timing of transporting the toner image to the secondary transfer unit 20.
In the secondary transfer unit 20, the unfixed toner image held on the intermediate transfer belt 15 is electrostatically transferred onto the paper P sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. Thereafter, the sheet P on which the toner image is electrostatically transferred is conveyed to the fixing device 60 by the conveying belt 55, and the fixing device 60 applies heat and pressure to the unfixed toner image on the sheet P to fix the toner image on the sheet P. To do. The paper P on which the fixed image is formed is conveyed to a paper discharge receiving portion (not shown) provided in the discharge portion of the image forming apparatus 100.

<Fixing device>
Next, the fixing device 60 will be described more specifically with reference to FIGS. 4 and 5. As shown in FIG. 4, the fixing device 60 includes a fixing roll (first rotating body) 61 that is driven to rotate in the rotational direction C, and a fixing belt that rotates in the rotational direction D (driven rotation) as the fixing roll 61 rotates. (Second rotating body) 62, disposed inside the fixing belt 62, and a pressure pad 64 (here, an elastic pressure pad 64b and a high-rigidity pad 64a) as a pressure member that presses the fixing belt 62 against the fixing roll 61 The main part is comprised from the sheet-like sliding member 68).
Further, a peeling assisting member 70 is installed on the downstream side of the contact area N as an auxiliary means for peeling the paper P from the fixing roll 61. The peeling assisting member 70 includes a peeling baffle 71 that is disposed in a direction facing the rotation direction C of the fixing roll 61 (counter direction) and close to the fixing roll 61, and a holder 72 that holds the peeling baffle 71. Has been.
Note that the present invention is not limited to this embodiment, and the pressure member may be disposed so that the fixing belt 62 and the fixing roll 61 are relatively pressurized. Accordingly, the fixing belt 62 side may be pressed by the fixing roll 61, and the fixing roll 61 side may be pressed by the pressure pad 64 via the fixing belt 62.

The fixing roll 61 is configured by laminating a heat-resistant elastic body layer 612 and a release layer 613 around a metal core (cylindrical cored bar) 611.
In this embodiment, the outer diameter and the wall thickness of the core 611 are usually 20 mm or more and 40 mm or less, for example, 1 mm or more and 3 mm or less in the case of aluminum, and 0.4 mm or more in the case of SUS or iron. It is about 5 mm or less.
Examples of the material of the heat resistant elastic layer 612 include silicone rubber and fluororubber having a hardness of about 15 ° to 45 ° (JIS-A).

  Examples of the material of the release layer 613 include a fluororesin. Specific examples include tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and the like. Moreover, you may use what mixed fillers, such as carbon, an alumina, barium sulfate, in those composite materials or those resin. The thickness of the release layer 613 is desirably 5 μm or more and 50 μm or less, and more desirably 10 μm or more and 40 μm or less. In this embodiment, a PFA tube having a thickness of 30 μm is covered.

  Inside the fixing roll 61, a halogen heater 66 is disposed as a heating unit. On the other hand, a temperature sensor 69 is disposed in contact with the surface of the fixing roll 61. The control unit 40 (see FIG. 3) of the image forming apparatus 100 controls the lighting of the halogen heater 66 based on the temperature measurement value by the temperature sensor 69, and the surface temperature of the fixing roll 61 sets the set temperature (for example, 170 ° C.). Adjust to maintain.

  The fixing belt 62 is rotatably supported by a pressure pad 64 and a belt travel guide 63 disposed inside, and a meandering prevention member 80 disposed at both ends as shown in FIG. The belt running guide 63 is formed of a low friction material, and the sliding resistance with the inner peripheral surface of the fixing belt 62 is reduced. Further, the belt running guide 63 is made of a low heat conductive material and suppresses heat conduction from the fixing belt 62.

The fixing roll 61 and the fixing belt 62 are in contact with each other on the outer peripheral surface to form a contact area N (pressing portion) to which the paper (P) is supplied. The fixing belt 62 is in contact with the fixing roll 61 in the contact area N. And are relatively pressurized. The sheet P is supplied to the contact area N via the fixing entrance guide 56.
The recording medium supplied to the contact area N is not limited to the paper P, and may be a sheet such as a plastic film. The sheet is not limited to a recording medium on which an image is recorded, and sheets for various purposes are used. Further, the number of sheets may be one, or a plurality of sheets as in the case of producing a laminate sheet.

The pressure pad 64 is disposed inside the fixing belt 62 and is pressed against the fixing roll 61 via the fixing belt 62, thereby forming a contact region N between the fixing roll 61 and the fixing belt 62. The pressure pad 64 is supported by the holder 65, and an elastic pressure pad (for pre-nip) 64b is arranged on the inlet side of the contact region N, thereby ensuring a wide contact region N. Further, a high-rigidity pad (for peeling nip) 64 a is disposed on the exit side of the contact area N, and the fixing roll 61 is distorted.
Examples of the material of the elastic pressure pad 64b include elastic bodies such as silicone rubber and fluorine rubber, and leaf springs. Further, it has a concave shape so as to follow the outer peripheral surface of the fixing roll 61.
Examples of the material of the high-rigidity pad 64a include heat-resistant resins such as polyphenylene sulfide (PPS), polyimide, polyester, and polyamide, materials that are reinforced by adding glass fibers to these resins, and metals such as iron, aluminum, and SUS. It is done.

A sliding member 68 is provided on the surface of the elastic pressure pad 64b and the high-rigidity pad 64a that contacts the fixing belt 62, and the sliding resistance between the inner peripheral surface of the fixing belt 62 and the pressure pad 64 is reduced. Examples of the material of the sliding member 68 include a sintered-molded PTFE resin sheet, a glass fiber sheet impregnated with a fluororesin, and a laminated sheet in which a fluororesin film sheet is heat-sealed and sandwiched between glass fibers.
The pressure between the pressure pad 64 and the fixing roll 61 is loaded by a member such as a spring (not shown), and the load is, for example, 100 N in an A4 size compatible (A4SEF paper passing width compatible) apparatus. 350N or less and 150N or more and 450N or less in an A3 size compatible device (A4LEF paper passing width compatible).

  In the holder 65, a lubricant application member 67 is disposed over the longitudinal direction of the fixing device 60. The lubricant application member 67 is disposed so as to be in contact with the inner peripheral surface of the fixing belt 62 and supplies an appropriate amount of lubricant such as amino-modified silicone oil. Thereby, the lubricant is supplied to the sliding portion between the fixing belt 62 and the sliding member 68, and the sliding resistance between the fixing belt 62 and the pressure pad 64 via the sliding member 68 is further reduced.

Further, the fixing device 60 according to the present embodiment includes a meandering prevention member 80 that contacts the end surface of the fixing belt 62 and prevents meandering thereof. FIG. 5 is a diagram illustrating a meandering prevention member.
As shown in FIG. 5, the meandering prevention member 80 includes a support portion 801, a flange portion 802, and an insertion portion 803. The insertion portions 803 are inserted from both ends of the fixing belt 62, and the flange portion 802 is inserted. When the fixing belt 62 meanders, the fixing belt 62 is disposed in a state of being separated by a certain distance so as to abut against the end face thereof.

The fixing belt 62 rotates along the outer peripheral surface of the belt traveling guide 63. Further, the fixing belt 62 is pressed against the fixing roll 61 by the pressure pad 64, and is rotated by the frictional force from the fixing roll 61 by the pressing force. At this time, it is affected by variations in component dimensions and the paper P passing through the contact area N. When the frictional force from the fixing roll 61 becomes non-uniform in the width direction, a force that moves in the axial direction acts on the fixing belt 62 and a so-called belt walk is generated that is offset to one of the ends. By providing the meandering prevention member 80, meandering of the fixing belt 62 is suppressed.
The meandering prevention member 80 is formed of a heat-resistant resin such as PPS, PET, PBT, or LCP, and further added with a filler for lowering durability and a friction coefficient.

  In the fixing device 60 having this configuration, when the paper P having an unfixed toner image is passed through the region N where the fixing roll 61 and the fixing belt 62 are in contact, the surface having the unfixed toner image is placed on the fixing roll 61. The opposite surface is in contact with the fixing belt 62 and pressed, and an unfixed toner image on the paper P is heated by the halogen heater 66 via the fixing roll 61 and fixed on the paper P.

  Hereinafter, the present invention will be described more specifically based on examples. In addition, this invention is not limited to a following example, unless it deviates from the summary.

<Paper passing test by image forming device>
The endless belt produced in Example 1 and Comparative Example 1 described later was mounted as a fixing belt on a fixing device having the configuration shown in FIG.
The fixing roll in the fixing device has a thickness of 0.6 mm and an outermost surface layer of silicone rubber (LSR manufactured by Shin-Etsu Chemical Co., Ltd.) on the surface of a carbon steel pipe having a wall thickness of 0.5 mm and an outer diameter of 25 mm. After inserting the PFA tube and carbon steel pipe into a mold having an inner diameter of about 26.2 mm so that a 30 μm thick PFA tube (PFA: copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether) is integrally coated, Silicone rubber was injected and molded into the gap between the tube and the carbon steel pipe. The PFA tube was formed by extruding PFA (950HP-Plus manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) and treating the inner surface with an excimer laser.

Further, this fixing device was attached to an image forming apparatus having the configuration shown in FIG. 3, and a paper passing test was conducted under the following conditions.
The paper used was XEROX 4200 paper (80 g / cm ² ) manufactured by Letter X Fuji Xerox Co., Ltd., and the image density was 5% for character images.
75,000 sheets of images were formed by the image forming apparatus, and the wear amount of the surface layer after running was evaluated.

  In the paper passing test, the pressure in the contact area between the fixing roll and the fixing belt (nip pressure) is increased 1.3 times the normal, and the amount of oil lubricant supplied to the inside of the fixing belt is as follows: The usual 30% was set. As described above, the evaluation conditions were set to be strict conditions, and the abrasion resistance of the fixing belt was evaluated.

<Maximum wear of surface layer>
The thickness of the fixing belt before image formation and the thickness after image formation of 75,000 sheets were measured, and the amount of change in thickness before and after image formation was defined as the amount of wear. The total length of the fixing belt was measured at intervals of 5 mm along the axial direction of the fixing belt. In addition, the measurement positions in the circumferential direction were set at four positions every 90 °. The maximum value among these measured values was defined as the maximum wear amount of the surface layer. In addition, the wear of the base material layer was very small and was within the range of the measurement variation accuracy, so it was set to 0.
The thickness of the surface layer was measured using an eddy current film thickness meter ISOSCOPE MP30 manufactured by Fisher Instruments.

Example 1
An endless belt was produced according to the following operation.
First, the surface of an aluminum cylindrical tube having an outer diameter of 30 mm and a length of 500 mm was roughened by blasting, and further a silicone release agent was applied and dried at 200 ° C. for 60 minutes. Thereafter, the mold was further heated and baked at 340 ° C. for 30 minutes, and a mold having a surface roughness Ra of 0.8 μm and a silicone mold release agent baked on the surface was prepared.

  Next, an N-methylpyrrolidone solution of a polyimide precursor adjusted to a viscosity of 120 Pa · s by a flow coating (spiral winding application) method on the surface center 400 mm of the prepared mold (manufactured by Ube Industries, Ltd .: trade name U) Varnish S) was applied. Next, the coating solution was dried while rotating the mold at 100 ° C. for 50 minutes to prepare a smoothed semi-dry film containing a polyimide precursor.

Next, 7.5 mass of N-methylpyrrolidone solution of polyimide precursor prepared by adjusting barium sulfate having an average particle diameter of 2.1 μm as a filler (manufactured by Sakai Chemical Co., Ltd .: trade name barium sulfate BMH) to a viscosity of 15 Pa · s. % Solution was applied on the semi-dry film by flow coating. Further, drying was performed to form a dry film for forming a base material layer.
When observed from the surface (outer peripheral surface) side of the dry film for forming the base layer, the total area of the convex portions by the filler particles on the surface is about 5%, and the average height of the convex portions is about 1.5 μm. Met.

On the other hand, in a fluororesin (PFA) dispersion solution (Mitsui / Dupont Fluorochemical Co., Ltd .: trade name 945HP-Plus), barium sulfate having an average particle diameter of 2.1 μm as a filler (manufactured by Sakai Chemical Co., Ltd .: trade name BMH) Was blended so that the ratio in the solid content was 20% by mass.
Next, carbon black (Ketjen Black dispersion manufactured by Lion Corporation) was blended as a conductive agent so that the ratio in the solid content was 2% by mass. Furthermore, the viscosity of the solution was adjusted with water and a thickener to prepare a surface layer forming coating solution.

  Next, the coating solution for forming the surface layer was applied by a dip coating method on the dry film for forming the base layer having a convex portion on the surface formed on the surface of the mold. Furthermore, the coating film was dried at 80 ° C. for 10 minutes. Furthermore, baking was performed at 380 ° C. for 60 minutes to cure the polyimide precursor in the dry film for forming the base material layer to form a film in which the base material layer and the surface layer were laminated.

  Next, the coating film formed on the surface of the mold was removed from the mold surface, and both ends were cut to obtain an endless belt. The obtained endless belt has a base material layer having a thickness of 70 μm containing a polyimide resin and a surface layer having a thickness of 23 μm formed on the outer peripheral surface of the base material layer. The endless belt has an inner diameter of 30 mm and a total length of 243 mm.

  The endless belt produced in this manner was attached to a fixing device as a fixing belt, and the paper passing test was performed using an image forming apparatus. The results are shown in FIG. The maximum wear amount of the belt surface layer was 21.1 μm.

(Example 2)
An endless belt was produced according to the following operation.
First, the surface of an aluminum cylindrical tube having an outer diameter of 30 mm and a length of 500 mm was roughened by blasting, and further a silicone release agent was applied and dried at 200 ° C. for 60 minutes. Thereafter, the mold was further heated and baked at 340 ° C. for 30 minutes, and a mold having a surface roughness Ra of 0.8 μm and a silicone mold release agent baked on the surface was prepared.

  Next, an N-methylpyrrolidone solution of a polyimide precursor adjusted to a viscosity of 120 Pa · s by a flow coating (spiral winding application) method on the surface center 400 mm of the prepared mold (manufactured by Ube Industries, Ltd .: trade name U) Varnish S) was applied. Next, the coating solution was dried while rotating the mold at 100 ° C. for 50 minutes to prepare a smoothed semi-dry film containing a polyimide precursor.

Next, an N-methylpyrrolidone solution of a polyimide precursor prepared by adjusting barium sulfate having an average particle diameter of 5.2 μm as a filler (manufactured by Sakai Chemical Co., Ltd .: trade name barium sulfate BMH-60) to a viscosity of 15 Pa · s is used. A 5% by mass dispersed solution was applied onto the semi-dry film by flow coating, and further dried.
When observed from the surface (outer peripheral surface) side of the dry film for forming the base layer, the total area of the convex portions by the filler particles on the surface was about 5%, and the height of the convex portions was about 3.5 μm. It was.

On the other hand, in a fluororesin (PFA) dispersion solution (Mitsui / Dupont Fluorochemical Co., Ltd .: trade name 945HP-Plus), barium sulfate having an average particle diameter of 2.1 μm as a filler (manufactured by Sakai Chemical Co., Ltd .: trade name BMH) Was blended so that the ratio in the solid content was 20% by mass.
Next, carbon black (Ketjen Black dispersion manufactured by Lion Corporation) was blended as a conductive agent so that the ratio in the solid content was 2% by mass. Furthermore, the viscosity of the solution was adjusted with water and a thickener to prepare a surface layer forming coating solution.

  Next, the coating solution for forming the surface layer was applied by a dip coating method on the dry film for forming the base layer having a convex portion on the surface formed on the surface of the mold. Furthermore, the coating film was dried at 80 ° C. for 10 minutes. Furthermore, baking was performed at 380 ° C. for 60 minutes to cure the polyimide precursor in the dry film for forming the base material layer to form a film in which the base material layer and the surface layer were laminated.

  Next, the coating film formed on the surface of the mold was removed from the mold surface, and both ends were cut to obtain an endless belt. The obtained endless belt has a base material layer having a thickness of 70 μm containing a polyimide resin and a surface layer having a thickness of 23 μm formed on the outer peripheral surface of the base material layer. The endless belt has an inner diameter of 30 mm and a total length of 243 mm.

  The endless belt produced in this manner was attached to a fixing device as a fixing belt, and the paper passing test was performed using an image forming apparatus. The results are shown in FIG. The maximum wear amount of the belt surface layer was 19.0 μm.

(Example 3)
An endless belt was produced according to the following operation.
First, the surface of an aluminum cylindrical tube having an outer diameter of 30 mm and a length of 500 mm was roughened by blasting, and further a silicone release agent was applied and dried at 200 ° C. for 60 minutes. Thereafter, the mold was further heated and baked at 340 ° C. for 30 minutes, and a mold having a surface roughness Ra of 0.8 μm and a silicone mold release agent baked on the surface was prepared.

  Next, an N-methylpyrrolidone solution of a polyimide precursor adjusted to a viscosity of 120 Pa · s by a flow coating (spiral winding application) method on the surface center 400 mm of the prepared mold (manufactured by Ube Industries, Ltd .: trade name U) Varnish S) was applied. Next, the coating solution was dried while rotating the mold at 100 ° C. for 50 minutes to prepare a smoothed semi-dry film containing a polyimide precursor.

Next, 22% by mass dispersion in an N-methylpyrrolidone solution of a polyimide precursor prepared by adjusting barium sulfate having an average particle size of 5.2 μm as a filler (manufactured by Sakai Chemical Co., Ltd .: trade name BMH-60) to a viscosity of 15 Pa · s. The obtained solution was applied on the semi-dry film by flow coating, and further dried.
When observed from the surface (outer peripheral surface) side of the dry film for forming the base material layer, the total area of the convex portions by the filler particles on the surface was about 15%, and the height of the convex portions was about 3.5 μm. It was.

On the other hand, in a fluororesin (PFA) dispersion solution (Mitsui / Dupont Fluorochemical Co., Ltd .: trade name 945HP-Plus), barium sulfate having an average particle size of 2.1 μm as a filler (manufactured by Sakai Chemical Co., Ltd .: trade name Barium sulfate) BMH) was blended so that the ratio in the solid content was 20% by mass.
Next, carbon black (Ketjen Black dispersion manufactured by Lion Corporation) was blended as a conductive agent so that the ratio in the solid content was 2% by mass. Furthermore, the viscosity of the solution was adjusted with water and a thickener to prepare a surface layer forming coating solution.

  Next, the coating solution for forming the surface layer was applied by a dip coating method on the dry film for forming the base layer having a convex portion on the surface formed on the surface of the mold. Furthermore, the coating film was dried at 80 ° C. for 10 minutes. Furthermore, baking was performed at 380 ° C. for 60 minutes to cure the polyimide precursor in the dry film for forming the base material layer to form a film in which the base material layer and the surface layer were laminated.

  Next, the coating film formed on the surface of the mold was removed from the mold surface, and both ends were cut to obtain an endless belt. The obtained endless belt has a base material layer having a thickness of 70 μm containing a polyimide resin and a surface layer having a thickness of 23 μm formed on the outer peripheral surface of the base material layer. The endless belt has an inner diameter of 30 mm and a total length of 243 mm.

  The endless belt produced in this manner was attached to a fixing device as a fixing belt, and the paper passing test was performed using an image forming apparatus. The results are shown in FIG. The maximum wear amount of the belt surface layer was 17.9 μm.

Example 4
An endless belt was produced according to the following operation.
First, the surface of an aluminum cylindrical tube having an outer diameter of 30 mm and a length of 500 mm was roughened by blasting, and further a silicone release agent was applied and dried at 200 ° C. for 60 minutes. Thereafter, the mold was further heated and baked at 340 ° C. for 30 minutes, and a mold having a surface roughness Ra of 0.8 μm and a silicone mold release agent baked on the surface was prepared.

  Next, an N-methylpyrrolidone solution of a polyimide precursor adjusted to a viscosity of 120 Pa · s by a flow coating (spiral winding application) method on the surface center 400 mm of the prepared mold (manufactured by Ube Industries, Ltd .: trade name U) Varnish S) was applied. Next, the coating solution was dried while rotating the mold at 100 ° C. for 50 minutes to prepare a smoothed semi-dry film containing a polyimide precursor.

Next, 35 mass in an N-methylpyrrolidone solution of a polyimide precursor in which barium sulfate having an average particle size of 5.2 μm as a filler (manufactured by Sakai Chemical Co., Ltd .: trade name barium sulfate BMH-60) was adjusted to a viscosity of 15 Pa · s. % Solution was applied on the semi-dry film by flow coating and further dried.
When observed from the surface (outer peripheral surface) side of the dry film for forming the base material layer, the total area of the convex portions by the filler particles on the surface was about 25%, and the height of the convex portions was about 3.5 μm. It was.

On the other hand, in a fluororesin (PFA) dispersion solution (Mitsui / Dupont Fluorochemical Co., Ltd .: trade name 945HP-Plus), barium sulfate having an average particle size of 2.1 μm as a filler (manufactured by Sakai Chemical Co., Ltd .: trade name Barium sulfate) BMH) was blended so that the ratio in the solid content was 20% by mass.
Next, carbon black (Ketjen Black dispersion manufactured by Lion Corporation) was blended as a conductive agent so that the ratio in the solid content was 2% by mass. Furthermore, the viscosity of the solution was adjusted with water and a thickener to prepare a surface layer forming coating solution.

  Next, the coating solution for forming the surface layer was applied by a dip coating method on the dry film for forming the base layer having a convex portion on the surface formed on the surface of the mold. Furthermore, the coating film was dried at 80 ° C. for 10 minutes. Furthermore, baking was performed at 380 ° C. for 60 minutes to cure the polyimide precursor in the dry film for forming the base material layer to form a film in which the base material layer and the surface layer were laminated.

  Next, the coating film formed on the surface of the mold was removed from the mold surface, and both ends were cut to obtain an endless belt. The obtained endless belt has a base material layer having a thickness of 70 μm containing a polyimide resin and a surface layer having a thickness of 23 μm formed on the outer peripheral surface of the base material layer. The endless belt has an inner diameter of 30 mm and a total length of 243 mm.

  The endless belt produced in this manner was attached to a fixing device as a fixing belt, and the paper passing test was performed using an image forming apparatus. The results are shown in FIG. The maximum wear amount of the belt surface layer was 16.9 μm.

(Example 5)
An endless belt was produced according to the following operation.
First, the surface of an aluminum cylindrical tube having an outer diameter of 30 mm and a length of 500 mm was roughened by blasting, and further a silicone release agent was applied and dried at 200 ° C. for 60 minutes. Thereafter, the mold was further heated and baked at 340 ° C. for 30 minutes, and a mold having a surface roughness Ra of 0.8 μm and a silicone mold release agent baked on the surface was prepared.

  Next, an N-methylpyrrolidone solution of a polyimide precursor adjusted to a viscosity of 120 Pa · s by a flow coating (spiral winding application) method on the surface center 400 mm of the prepared mold (manufactured by Ube Industries, Ltd .: trade name U) Varnish S) was applied. Next, the coating solution was dried while rotating the mold at 100 ° C. for 50 minutes to prepare a smoothed semi-dry film containing a polyimide precursor.

Next, 43 masses in a N-methylpyrrolidone solution of a polyimide precursor in which barium sulfate having an average particle size of 5.2 μm as a filler (manufactured by Sakai Chemical Co., Ltd .: trade name barium sulfate BMH-60) was adjusted to a viscosity of 15 Pa · s. % Solution was applied on the semi-dry film by flow coating and further dried.
When observed from the surface (outer peripheral surface) side of the dry film for forming the base material layer, the total area of the convex portions by the filler particles on the surface was about 30%, and the height of the convex portions was about 3.5 μm. It was.

On the other hand, in a fluororesin (PFA) dispersion solution (Mitsui / Dupont Fluorochemical Co., Ltd .: trade name 945HP-Plus), barium sulfate having an average particle size of 2.1 μm as a filler (manufactured by Sakai Chemical Co., Ltd .: trade name Barium sulfate) BMH) was blended so that the ratio in the solid content was 20% by mass.
Next, carbon black (Ketjen Black dispersion manufactured by Lion Corporation) was blended as a conductive agent so that the ratio in the solid content was 2% by mass. Furthermore, the viscosity of the solution was adjusted with water and a thickener to prepare a surface layer forming coating solution.

  Next, the coating solution for forming the surface layer was applied by a dip coating method on the dry film for forming the base layer having a convex portion on the surface formed on the surface of the mold. Furthermore, the coating film was dried at 80 ° C. for 10 minutes. Furthermore, baking was performed at 380 ° C. for 60 minutes to cure the polyimide precursor in the dry film for forming the base material layer to form a film in which the base material layer and the surface layer were laminated.

  Next, the coating film formed on the surface of the mold was removed from the mold surface, and both ends were cut to obtain an endless belt. The obtained endless belt has a base material layer having a thickness of 70 μm containing a polyimide resin and a surface layer having a thickness of 23 μm formed on the outer peripheral surface of the base material layer. The endless belt has an inner diameter of 30 mm and a total length of 243 mm.

  The endless belt produced in this manner was attached to a fixing device as a fixing belt, and the paper passing test was performed using an image forming apparatus. The results are shown in FIG. The maximum wear amount of the belt surface layer was 15.2 μm. However, a slight image quality defect occurred due to toner adhering at the belt end wear part.

(Example 6)
An endless belt was produced according to the following operation.
First, the surface of an aluminum cylindrical tube having an outer diameter of 30 mm and a length of 500 mm was roughened by blasting, and further a silicone release agent was applied and dried at 200 ° C. for 60 minutes. Thereafter, the mold was further heated and baked at 340 ° C. for 30 minutes, and a mold having a surface roughness Ra of 0.8 μm and a silicone mold release agent baked on the surface was prepared.

  Next, an N-methylpyrrolidone solution of a polyimide precursor adjusted to a viscosity of 120 Pa · s by a flow coating (spiral winding application) method on the surface center 400 mm of the prepared mold (manufactured by Ube Industries, Ltd .: trade name U) Varnish S) was applied. Next, the coating solution was dried while rotating the mold at 100 ° C. for 50 minutes to prepare a smoothed semi-dry film containing a polyimide precursor.

Next, as a filler, barium sulfate having an average particle size of 5.2 μm (manufactured by Sakai Chemical Co., Ltd .: trade name barium sulfate BMH-60) is used as a primer solution for bonding polyimide and fluororesin (Mitsui / DuPont Fluorochemical Co., Ltd.) (Product name: PJ-YL902) 34% by weight dispersed solution was applied onto the polyimide substrate by flow coating, and further dried.
The total area of the convex portions by the filler particles in the substrate surface observed from the belt surface was about 25%, and the average height of the convex portions was about 4.0 μm.

  On the other hand, in a fluororesin (PFA) dispersion solution (Mitsui / Dupont Fluorochemical Co., Ltd .: trade name 945HP-Plus), barium sulfate having an average particle size of 2.1 μm as a filler (manufactured by Sakai Chemical Co., Ltd .: trade name Barium sulfate) BMH) was blended so that the ratio in the solid content was 20% by mass.

  Next, carbon black (Ketjen Black dispersion manufactured by Lion Corporation) was blended as a conductive agent so that the ratio in the solid content was 2% by mass. Furthermore, the viscosity of the solution was adjusted with water and a thickener to prepare a surface layer forming coating solution.

  Next, the surface layer forming coating solution was applied by a dip coating method on a polyimide base material having a convex portion on the surface formed on the mold surface. Further, the coating solution was dried at 80 ° C. for 10 minutes. Further, baking was performed at 380 ° C. for 60 minutes.

  Next, the coating film formed on the surface of the mold was removed from the mold surface, and both ends were cut to obtain an endless belt. The obtained endless belt has a base material layer having a thickness of 70 μm containing a polyimide resin and a surface layer having a thickness of 23 μm formed on the outer peripheral surface of the base material layer. The endless belt has an inner diameter of 30 mm and a total length of 243 mm.

  The endless belt produced in this manner was attached to a fixing device as a fixing belt, and the paper passing test was performed using an image forming apparatus. The results are shown in FIG. The maximum wear amount of the belt surface layer was 15.8 μm.

(Example 7)
An endless belt was produced according to the following operation.
First, the surface of an aluminum cylindrical tube having an outer diameter of 30 mm and a length of 500 mm was roughened by blasting, and further a silicone release agent was applied and dried at 200 ° C. for 60 minutes. Thereafter, the mold was further heated and baked at 340 ° C. for 30 minutes, and a mold having a surface roughness Ra of 0.8 μm and a silicone mold release agent baked on the surface was prepared.

  Next, an N-methylpyrrolidone solution of a polyimide precursor adjusted to a viscosity of 120 Pa · s by a flow coating (spiral winding application) method on the surface center 400 mm of the prepared mold (manufactured by Ube Industries, Ltd .: trade name U) Varnish S) was applied. Next, the coating solution was dried while rotating the mold at 100 ° C. for 50 minutes to prepare a smoothed semi-dry film containing a polyimide precursor.

Next, 35% by mass dispersion in an N-methylpyrrolidone solution of a polyimide precursor prepared by adjusting barium sulfate having an average particle size of 8.1 μm as a filler (manufactured by Sakai Chemical Co., Ltd .: trade name barium sulfate BA) to a viscosity of 15 Pa · s. The obtained solution was applied on the semi-dry film by flow coating, and further dried.
When observed from the surface (outer peripheral surface) side of the dry film for forming the base layer, the total area of the convex portions by the filler particles on the surface was about 25%, and the height of the convex portions was about 6.5 μm. It was.

On the other hand, in a fluororesin (PFA) dispersion solution (Mitsui / Dupont Fluorochemical Co., Ltd .: trade name 945HP-Plus), barium sulfate having an average particle size of 2.1 μm as a filler (manufactured by Sakai Chemical Co., Ltd .: trade name Barium sulfate) BMH) was blended so that the ratio in the solid content was 20% by mass.
Next, carbon black (Ketjen Black dispersion manufactured by Lion Corporation) was blended as a conductive agent so that the ratio in the solid content was 2% by mass. Furthermore, the viscosity of the solution was adjusted with water and a thickener to prepare a surface layer forming coating solution.

  Next, the coating solution for forming the surface layer was applied by a dip coating method on the dry film for forming the base layer having a convex portion on the surface formed on the surface of the mold. Furthermore, the coating film was dried at 80 ° C. for 10 minutes. Furthermore, baking was performed at 380 ° C. for 60 minutes to cure the polyimide precursor in the dry film for forming the base material layer to form a film in which the base material layer and the surface layer were laminated.

  Next, the coating film formed on the surface of the mold was removed from the mold surface, and both ends were cut to obtain an endless belt. The obtained endless belt has a base material layer having a thickness of 70 μm containing a polyimide resin and a surface layer having a thickness of 23 μm formed on the outer peripheral surface of the base material layer. The endless belt has an inner diameter of 30 mm and a total length of 243 mm.

  The endless belt produced in this manner was attached to a fixing device as a fixing belt, and the paper passing test was performed using an image forming apparatus. The results are shown in FIG. The maximum wear amount of the belt surface layer was 14.8 μm.

(Example 8)
An endless belt was produced according to the following operation.
First, the surface of an aluminum cylindrical tube having an outer diameter of 30 mm and a length of 500 mm was roughened by blasting, and further a silicone release agent was applied and dried at 200 ° C. for 60 minutes. Thereafter, the mold was further heated and baked at 340 ° C. for 30 minutes, and a mold having a surface roughness Ra of 0.8 μm and a silicone mold release agent baked on the surface was prepared.

  Next, an N-methylpyrrolidone solution of a polyimide precursor adjusted to a viscosity of 120 Pa · s by a flow coating (spiral winding application) method on the surface center 400 mm of the prepared mold (manufactured by Ube Industries, Ltd .: trade name U) Varnish S) was applied. Next, the coating solution was dried while rotating the mold at 100 ° C. for 50 minutes to prepare a smoothed semi-dry film containing a polyimide precursor.

Next, 37 mass% dispersion in an N-methylpyrrolidone solution of a polyimide precursor in which an aluminum oxide having an average particle diameter of 8.4 μm as a filler (manufactured by Fujimi Incorporated: trade name WA # 1500) was adjusted to a viscosity of 15 Pa · s. The obtained solution was applied on the semi-dry film by flow coating, and further dried.
When observed from the surface (outer peripheral surface) side of the dry film for forming the base layer, the total area of the convex portions by the filler particles on the surface was about 25%, and the height of the convex portions was about 6.7 μm. It was.

On the other hand, a fluororesin (PFA) dispersion (Mitsui / DuPont Fluoro Chemical Co., Ltd .: trade name 945HP-Plus) and an aluminum oxide having an average particle size of 2 μm as a filler (Fujimi Incorporated: trade name WA # 6000) Was blended so that the ratio in the solid content was 20% by mass.
Next, carbon black (Ketjen Black dispersion manufactured by Lion Corporation) was blended as a conductive agent so that the ratio in the solid content was 2% by mass. Furthermore, the viscosity of the solution was adjusted with water and a thickener to prepare a surface layer forming coating solution.

  Next, the coating solution for forming the surface layer was applied by a dip coating method on the dry film for forming the base layer having a convex portion on the surface formed on the surface of the mold. Furthermore, the coating film was dried at 80 ° C. for 10 minutes. Furthermore, baking was performed at 380 ° C. for 60 minutes to cure the polyimide precursor in the dry film for forming the base material layer to form a film in which the base material layer and the surface layer were laminated.

  Next, the coating film formed on the surface of the mold was removed from the mold surface, and both ends were cut to obtain an endless belt. The obtained endless belt has a base material layer having a thickness of 70 μm containing a polyimide resin and a surface layer having a thickness of 23 μm formed on the outer peripheral surface of the base material layer. The endless belt has an inner diameter of 30 mm and a total length of 243 mm.

  The endless belt produced in this manner was attached to a fixing device as a fixing belt, and the paper passing test was performed using an image forming apparatus. The results are shown in FIG. The maximum wear amount of the belt surface layer was 14.1 μm.

(Comparative Example 1)
An endless belt was produced in the same manner as in Example 1 except that the filler dispersion liquid for forming the convex portion on the surface of the base material layer was not applied in Example 1.
The obtained endless belt has a 70 μm-thick base material layer containing a polyimide resin and a 23 μm-thick surface layer formed on the outer periphery of the base material layer. The endless belt has an inner diameter of 30 mm and a total length of 243 mm.

  The endless belt produced as described above was used as a fixing belt in a fixing device in the same manner as in Example 1, and the paper passing test was performed using an image forming apparatus. The results are shown in FIG. The maximum amount of wear of the surface layer was about 23 μm, and the surface layer was worn at the locations where both edges of the paper passed, and part of the base material layer was exposed.

  From the results shown in FIG. 6, it can be seen that the wear amount of the surface layer is smaller in the fixing belt provided with the convex portion on the surface of the base material layer, and the maximum wear amount of the surface layer is effectively suppressed. .

  Table 1 below shows the main structures of the fixing belts produced in the examples and comparative examples and the evaluation results of the amount of wear.

  Although the embodiments and examples have been described above, the present invention is not limited to the above-described embodiments and examples, and various modifications may be made within the scope of the gist.

1Y, 1M, 1C, 1K Image forming unit 2 Fluorine-containing resin 3 Surface layer 4 First particle (filler particle)
5 Base material layer 6 2nd particle (filler particle)
DESCRIPTION OF SYMBOLS 10 Primary transfer part 11 Photoconductor drum 12 Charger 13 Laser exposure device 14 Developer 15 Intermediate transfer belt 16 Primary transfer roll 17 Drum cleaner 20 Secondary transfer part 22 Secondary transfer roll 25 Back roll 26 Power supply roll 31 Drive roll 32 Support Roll 33 Tension Roll 34 Cleaning Unit Back Roll 35 Intermediate Transfer Belt Cleaner 40 Control Unit 43 Image Density Sensor 50 Paper Storage Unit 51 Take-out Roll 52 Transport Roll 53 Guide Member 55 Transport Belt 56 Fixing Entrance Guide 60 Fixing Device 61 Fixing Roll 62 Fixing belt 63 Belt running guide 64 Pressure pad 64b High rigidity pad 64a Elastic pressure pad 65 Holder 66 Halogen heater 67 Lubricant application member 68 Sliding member 69 Temperature sensor 70 Peeling auxiliary member 80 Meandering prevention member 100 Image forming apparatus

Claims (5)

A base material layer;
A surface layer that is provided on the outer peripheral surface of the base material layer and includes a fluorine-containing resin and first particles having higher hardness than the fluorine-containing resin;
Second particles that are higher in hardness than the fluorine-containing resin and are inorganic materials partially embedded in the outer peripheral surface of the base material layer;
Having a fixing belt.   The fixing belt according to claim 1, wherein an average particle diameter of the second particles is larger than an average particle diameter of the first particles.   The fixing belt according to claim 1, wherein a ratio of a total area of a portion where the second particles are exposed to an outer peripheral surface of the base material layer is 5% or more and 25% or less. A first rotating body that is rotationally driven;
4. The fixing belt according to claim 1, wherein the first rotating body and the outer peripheral surface of the first rotating body are arranged in contact with each other, and the first rotating body rotates with the rotation of the first rotating body. A second rotating body;
When a recording medium having an unfixed toner image is passed through a region where the first rotating body and the second rotating body are in contact with each other, an unfixed image on the recording medium is passed through the first rotating body. Heating means for heating the toner image;
A fixing device provided with An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic latent image forming unit that forms an electrostatic latent image on the surface of the image carrier charged by the charging unit;
Developing means for developing the electrostatic latent image formed on the surface of the image carrier with a developer containing toner to form a toner image;
Transfer means for transferring the toner image formed on the surface of the image carrier to a recording medium;
A fixing unit including the fixing device according to claim 4, wherein the toner image transferred to the recording medium is fixed to the recording medium;
An image forming apparatus comprising: