JP2011164571A - Endless belt for image forming apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endless belt for an image forming apparatus which can retain releasing property for a longer time compared with the one includes fluorinated polyimide resin having no ether groups in the main chain. <P>SOLUTION: The surface layer is constituted in such a manner that at least the outer surface of the surface layer includes: a composite resin composition including 25-89.5 mass.% of fluorinated polyimide resin having an ether group in the main chain; 10-70 mass.% of fluororesin; and 0.5-5.0 mass.% of conductive particles. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an endless belt for an image forming apparatus and an image forming apparatus.

  In an image forming apparatus such as a copying machine, a printer, a facsimile, or an electrophotographic apparatus, an unfixed image or an untransferred image such as a toner image is fixed on a recording member such as a recording sheet by, for example, heating or electrostatic force. A fixing belt or an intermediate transfer belt made of a rotating body made of metal, plastic, rubber or the like to be transferred is used. With recent downsizing and higher performance of image forming apparatuses, it may be preferable that the above-mentioned rotating body is deformable, and such a rotating body is seamlessly made of a thin plastic film. An endless belt is used. As a material used for such an endless belt, a polyimide resin is preferably used in terms of strength, dimensional stability, heat resistance, and the like (hereinafter, polyimide may be abbreviated as “PI”).

  As a fixing device using an endless belt, for example, a belt nip type has been proposed (for example, see Patent Document 1). The fixing device mainly includes a rotatable fixing roll and an endless belt that is arranged to contact the fixing roll and rotate according to the fixing roll. The fixing operation using the fixing device having such a configuration is such that the toner image is transferred to the surface of the recording paper by passing the recording paper on which the toner image is formed through the contact portion between the fixing roll whose surface is heated and the endless belt. It is carried out by heating and fixing. At that time, in order to press the endless belt against the fixing roll at the contact portion (nip), a support body such as a pressure pad and a sliding sheet is provided on the inner peripheral surface of the endless belt.

  As a method for producing an endless belt made of PI resin, for example, as described in Patent Documents 2 and 3, a PI precursor solution is applied to the surface of a core body (base material layer) by a dip coating method, There is a method of forming a PI resin film on the outer surface of the core body by drying it in a hot air drying oven or the like and then baking it to a predetermined temperature.

  On the other hand, when an endless belt is used in an electrophotographic apparatus, an endless belt made of a PI resin composed of a plurality of layers having a release layer (surface layer) formed on the surface is used (for example, see Patent Document 4).

In this case, as the release layer, PFA resin (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) is mainly used. Depending on the application, a resin in which conductivity is improved by dispersing carbon, or SiO Resin or the like whose durability has been improved by mixing an inorganic filler such as ₂ or BaSO ₄ is used.

  On the other hand, when an endless belt is used in an electrophotographic apparatus, depending on the application in which the endless belt is used, the sliding resistance with a sliding sheet (support) disposed so as to be in contact with the inner peripheral surface of the endless belt is lowered. In addition, there are cases where it is required to suppress the sliding noise generated when the endless belt rotates. Also, an endless belt having different surface roughness between the outer peripheral surface and the inner peripheral surface, such that the outer peripheral surface is a smooth surface in terms of image quality and the inner peripheral surface is a rough surface in terms of belt running performance. May be required.

  As methods for not using PFA resin as the release layer, for example, methods using fluorinated polyimide having no ether group in the main chain are described in Patent Documents 5, 6, and 7.

JP-A-8-262903 Japanese Patent Laid-Open No. 61-273919 JP 2002-091027 A JP 2000-351466 A Patent publication 3069041 JP 2000-137396 A Patent Publication No. 4215492

  The present invention provides an endless belt for an image forming apparatus capable of maintaining releasability for a long period of time as compared with a case where the main chain is made of a fluorinated polyimide resin having no ether group. With the goal.

  In order to achieve the above object, according to the present invention, the following endless belt for an image forming apparatus and an image forming apparatus are provided.

[1] It has a surface layer, and at least the outer surface of the surface layer has 25 to 89.5% by mass of fluorinated polyimide resin having an ether group in the main chain, 10 to 70% by mass of fluororesin, and conductive An endless belt for an image forming apparatus comprising a composite resin composition containing 0.5 to 5.0% by weight of conductive particles.

  [2] The fluorinated polyimide resin having an ether group in the main chain is a fluorinated polyamic acid synthesized from at least a partially fluorinated acid anhydride and at least a partially fluorinated diamine. The endless belt for an image forming apparatus according to the above [1], which is a resin prepared from 1.

[3] The acid anhydride in which at least a part thereof is fluorinated and the diamine in which at least a part thereof is fluorinated are a fluorine group (—F) and / or a perfluoroalkyl group (—C _n F _{2n + 1).} : N is an integer of 1 or more) The endless belt for an image forming apparatus according to the above [2].

[4] The acid anhydride in which at least a part thereof is fluorinated is represented by the following chemical formulas (1) to (3):

  The diamines represented by the above and at least a part of which are fluorinated are represented by the following chemical formula (4):

The endless belt for an image forming apparatus according to [3], which is represented by

[5] The endless belt for an image forming apparatus according to [4], wherein the diamine having at least a part thereof fluorinated is one represented by the following chemical formulas (5) to (15).

[6] The endless belt for an image forming apparatus according to any one of [1] to [5], wherein the fluororesin has a particle size of 0.05 μm to 1.0 μm.

[7] The endless belt for an image forming apparatus according to any one of [1] to [6], wherein the fluororesin is a crosslinked polytetrafluoroethylene (PTFE) -containing fluororesin.

[8] The crosslinked PTFE-containing fluororesin may be a crosslinked PTFE alone, a resin composition of crosslinked PTFE and PTFE, or a resin composition of crosslinked PTFE and a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) resin. The endless belt for an image forming apparatus according to [7], which is a configured fluororesin.

[9] The cross-linked PTFE constituting the cross-linked PTFE-containing fluororesin is obtained by polymerizing a monomer in an acetone solvent by irradiation with an electron beam, according to the above [7] or [8]. Endless belt for image forming apparatus.
[10] A single-layer structure of only the surface layer, a two-layer structure of the surface layer and a base material layer formed so as to be in contact with the surface layer, or the surface layer, the surface layer, and the base material layer The endless belt for an image forming apparatus according to any one of [1] to [5], which has a three-layer structure including an intermediate layer formed between the substrate layer and the base material layer.
[11] In the case of having the two-layer structure or the three-layer structure, the base layer in the two-layer structure and the intermediate layer in the three-layer structure formed so as to be in contact with the surface layer each have conductivity. The endless belt for an image forming apparatus according to the above [10], which is a conductive base material layer and a conductive intermediate layer.
[12] The endless belt for an image forming apparatus according to [11], wherein the conductive base layer and the conductive intermediate layer are made of polyimide (PI) in which conductive particles are dispersed, or metal.
[13] The endless belt for an image forming apparatus according to [12], wherein the conductive particles are carbon black.

[14] An image forming apparatus using the endless belt for an image forming apparatus according to any one of [1] to [13].

    According to the inventions according to claims 1 to 6, an image forming apparatus capable of maintaining releasability over a long period of time as compared with a case where the main chain is made of a fluorinated polyimide resin having no ether group. An endless belt can be provided.

  According to the inventions according to claims 7 to 9, it is possible to provide an endless belt for an image forming apparatus with improved wear resistance in addition to the above-described mold release properties.

  According to the invention which concerns on Claims 10-13, compared with the case where the base material layer or intermediate | middle layer which contact | connects a surface layer is insulating, when the film thickness of the surface layer was set thin, or it became thin by abrasion etc. Even in this case, an endless belt for an image forming apparatus capable of maintaining predetermined conductivity while maintaining releasability and capable of retaining releasability over a long period of time is provided. be able to.

  According to the fourteenth aspect of the present invention, it is possible to provide an image forming apparatus in which contamination of an image is suppressed for a long period of time as compared with a case where an endless belt for an image forming apparatus having this configuration is not used.

1 is a perspective view showing an endless belt for an image forming apparatus according to a first embodiment of the present invention (when it has a single-layer structure with only a surface layer). 1B is a longitudinal sectional view of an endless belt for the image forming apparatus shown in FIG. 1A. FIG. It is a cross-sectional view of an endless belt for the image forming apparatus shown in FIG. 1A. It is a perspective view which shows the endless belt for the image forming apparatus which concerns on the 2nd Embodiment of this invention (when it consists of a multilayer of a surface layer and a base material layer). It is a longitudinal cross-sectional view of the endless belt for image forming apparatuses shown to FIG. 2A. It is a cross-sectional view of an endless belt for the image forming apparatus shown in FIG. 2A. FIG. 6 is a perspective view showing an endless belt for an image forming apparatus according to a third embodiment of the present invention (in the case of a multilayer of a surface layer, a base material layer, and an elastic layer). 3B is a longitudinal sectional view of an endless belt for the image forming apparatus shown in FIG. 3A. FIG. It is a cross-sectional view of an endless belt for the image forming apparatus shown in FIG. 3A. FIG. 1B is a perspective view showing a state where the endless belt for the image forming apparatus shown in FIG. 1A is supported by a support.

[Endless Belt for Image Forming Apparatus According to First Embodiment]
FIG. 1A is a perspective view showing an endless belt for an image forming apparatus according to a first embodiment of the present invention (in the case of a single layer consisting of only a surface layer). 1B is a longitudinal sectional view of an endless belt for the image forming apparatus shown in FIG. 1A. 1C is a cross-sectional view of the endless belt for the image forming apparatus shown in FIG. 1A.

  As shown in FIGS. 1A to 1C, an endless belt 10 for an image forming apparatus according to a first embodiment of the present invention is an image forming apparatus (not shown) that forms an image on a recording member (not shown). 2) is an endless belt 10 for an image forming apparatus used as a fixing belt or an intermediate transfer belt for fixing or transferring an unfixed image or an untransferred image on a recording member, and is in contact with the recording member at the time of fixing or transferring And at least the outer surface of the surface layer 11 has a fluorinated polyimide resin having an ether group in the main chain of 25 to 89.5% by mass, a fluororesin of 10 to 70% by mass, It is comprised from the composite resin composition containing 0.5-5.0 mass% of electroconductive particles.

  In FIGS. 1A to 1C, as described above, a case where a cylindrical surface layer 11 is used as the surface layer 11 is shown. However, for example, a cylindrical shape such as a rectangular tube or an elliptical cylinder, or a column shape such as a circular column may be used. Good. Moreover, although the case where the thing which has the single layer structure only of the surface layer 11 as mentioned above was used was shown, for example, even if the surface layer 11 itself consists of multiple layers, it consists of a single layer and is outside from the inside. A composite resin composition containing 25 to 89.5% by mass of a fluorinated polyimide resin having an ether group in the main chain, 10 to 70% by mass of a fluororesin, and 0.5 to 5.0% by mass of conductive particles The content of the product may be increased stepwise or stepwise. In these cases, the outer surface needs to be composed of the composite resin composition described above.

  Note that the endless belt 10 for an image forming apparatus according to the first embodiment has a layer other than the surface layer 11, for example, a base material layer 12 (described later), even if the surface layer 11 itself is composed of a plurality of layers. 2 (see FIG. 2A) and the like, it is included in “when it has a single-layer structure of only the surface layer 11” (that is, when it has no other layer such as a base material layer as the endless belt 10).

  As described above, at least the outer surface of the surface layer 11 of the endless belt 10 for the image forming apparatus according to the first embodiment has a fluorinated polyimide resin having an ether group in the main chain of 25 to 89.5% by mass. And a composite resin composition containing 10 to 70% by mass of a fluororesin and 0.5 to 5.0% by mass of conductive particles.

  As this composite resin composition, for example, as a precursor of a fluorinated polyimide resin having an ether group in the main chain, an acid anhydride that is at least partly fluorinated and a diamine that is at least partly fluorinated Prepared from a dispersion as a precursor of a composite resin composition, in which a fluororesin and conductive particles are dispersed in a solution of a fluorinated polyamic acid synthesized from the above (for example, an N-methylpyrrolidone solution). Can be mentioned.

  Moreover, as this composite resin composition, what was prepared by heating the above-mentioned dispersion liquid as a precursor of a composite resin composition can be mentioned, for example.

  Hereinafter, the fluorinated polyimide resin having an ether group in the main chain, the fluororesin, and the conductive particles constituting the composite resin composition will be described in order, and then the fluorinated polyimide resin having an ether group in the main chain will be described. An explanation will be given of preparing a dispersion as a precursor of a composite resin composition by dispersing a fluororesin and conductive particles in a solution of a fluorinated polyamic acid that is a precursor.

First, a fluorinated polyimide resin having an ether group in the main chain will be described. This fluorinated polyimide resin having an ether group in the main chain is used for enabling the endless belt 10 to maintain an appropriate releasability over a long period of time. Fluorinated polyamic acid as a precursor of fluorinated polyimide resin having an ether group in the main chain is synthesized from the above-mentioned acid anhydrides that are at least partly fluorinated and diamines that are at least partly fluorinated. As these acid anhydrides and diamines, those having a fluorine group (-F) and / or a perfluoroalkyl group (-C _n F _{2n + 1} : n is an integer of 1 or more) can be mentioned. be able to. _{N in the} perfluoroalkyl group (—C _n F _{2n + 1} ) is preferably 1 to 9, and specific examples include —CF ₃ , —C ₂ F ₅ , —C ₃ F _{7 and the} like. . In addition, at least one of the above-described acid anhydride at least partially fluorinated and diamines at least partially fluorinated must have an ether group in the main chain.

  Specifically, examples of the acid anhydride at least partially fluorinated include those represented by the above chemical formulas (1) to (3).

  The diamines at least partially fluorinated are generally represented by the above chemical formula (4), specifically, for example, those represented by the above chemical formulas (5) to (15). Can be mentioned.

As described above, at least a part of the fluorinated acid anhydride and at least a part of the fluorinated diamine used in the present invention are not only completely fluorinated but also partly fluorinated. Without being fluorinated (without being substituted with a fluorine group (—F) and / or a perfluoroalkyl group (—C _n F _{2n + 1,} where n is an integer of 1 or more)), remain a hydrogen group (—H) Can be used.

  The fluorinated polyimide resin having an ether group in the main chain is usually blended at a ratio of 25 to 89.5% by mass, preferably 35 to 75% by mass with respect to the entire composite resin composition. If it is less than 25% by mass, the endless belt 10 may be difficult to polymerize from a polyamic acid and have a problem of insufficient durability. If it exceeds 75% by mass, there may be a problem that it is difficult to achieve both releasability and electrical resistance control when used for fixing.

  Next, the fluororesin will be described. The fluororesin is used for improving the peelability (release property) on the surface of an endless belt for an image forming apparatus. For example, when the endless belt 10 is used as a fixing belt (fixing body, fixing film), it is effective for improving the releasability of the toner image adhering to the outer peripheral surface of the endless belt 10. A fluororesin is normally mix | blended in the ratio of 10-70 mass% with respect to the whole composite resin composition, Preferably, 20-60 mass%. If it is less than 10% by mass, the peelability of the surface of the endless belt 10 may be insufficient. If it exceeds 70% by mass, polymerization of polyamic acid may be hindered and durability may be insufficient.

  Such fluororesins include polytetrafluoroethylene (PTFE), cross-linked polytetrafluoroethylene (PTFE) -containing fluororesin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene. A copolymer (FEP) or the like is preferable. Among these, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and a crosslinked polytetrafluoroethylene (PTFE) -containing fluororesin are more preferable. Among these, a crosslinked polytetrafluoroethylene (PTFE) -containing fluororesin is particularly preferable. The fluororesin used as the dispersant is preferably a particle having an average particle diameter of 0.05 to 1 μm, more preferably 0.1 to 0.3 μm.

  Here, the above-mentioned crosslinked PTFE-containing fluororesin is preferably a fluororesin composed of a crosslinked PTFE alone, a resin composition of crosslinked PTFE and PTFE, or a resin composition of PFA resin. In this case, the particle diameter of the crosslinked PTFE-containing fluororesin is preferably 0.05 to 1.0 μm, and more preferably 0.1 to 0.3 μm. Further, the crosslinked PTFE constituting the crosslinked PTFE-containing fluororesin is preferably one obtained by polymerizing a monomer in an acetone solvent by irradiating with an electron beam (hereinafter sometimes referred to as “electron beam crosslinked PTFE”). .

  The above-mentioned crosslinked PTFE-containing fluororesin can improve the abrasion resistance in addition to the above-described improvement in peelability (releasability) on the surface of an endless belt for an image forming apparatus. And wear resistance can both be achieved. In addition, electron beam cross-linked PTFE is preferable as a dispersant because the particle size can be controlled to a small size of 1 μm or less.

  Next, the conductive particles will be described. For example, in the case of carbon black, the conductive particles are used to improve electrostatic offset. For example, when the endless belt 10 is used as a charging body using an electrostatic force such as a transfer belt (transfer body, transfer (contact charging) film), conductive particles are dispersed in the surface layer 11 of the endless belt 10. , Electrostatic offset can be reduced. The conductive particles are usually blended at a ratio of 0.5 to 5.0% by mass, preferably 1 to 3% by mass with respect to the entire composite resin composition. If it is less than 0.5% by mass, the electrical resistance may become unstable, and if it exceeds 5% by mass, the improvement in peelability (release property) on the surface of the endless belt may be hindered.

Examples of such conductive particles include carbon black, carbon beads obtained by granulating carbon black, carbon fibers, carbon-based materials such as graphite, metals or alloys such as copper, silver, and aluminum, tin oxide, indium oxide, Examples thereof include conductive metal oxides such as antimony oxide and SnO ₂ —In ₂ O ₃ composite oxide, and conductive whiskers such as potassium titanate. Among these, conductive particles used as a dispersant are preferable because predetermined conductivity can be obtained with a small amount of carbon black, particularly ketjen black. In addition, as an average particle diameter of such electroconductive particle, 20-100 nm is preferable. Moreover, it is preferable from a viewpoint of coexistence of mold release property and electrical resistance control that electroconductive particle can control electroconductivity with a small addition amount that it is what has a hollow shell-like structure.

  Compounding amount of fluororesin (PFTE) and conductive particles (carbon black) and composite resin composition of surface layer (when using fluorinated polyimide (10FEDA + 4FMPD) as fluorinated polyimide resin having ether group in main chain) The result of investigating the relationship with the peeling force of) is shown below. That is, in a system in which carbon black is not blended, the composite resin composition peels off as the blending amount of the fluororesin (PFTE) increases to 0 mass%, 5 mass%, 10 mass%, 20 mass%, and 30 mass%. It can be seen that the force [N] decreases to 1.4N, 0.9N, 0.4N, 0.3N, and 0.2N, and the peelability is improved. As described above, the peel force [N] when the blending amount of the fluororesin (PFTE) is 30% by mass is 0.2N, which is the case of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA). It can be seen that when the blending amount of the fluororesin (PFTE) is 30% by mass, the same peelability as PFA can be obtained. Further, in a system in which 5% by mass of carbon black was blended, when the blending amount of the fluororesin (PFTE) was 10% by mass, the peeling force [N] of the composite resin composition was about 0.4N and did not change. From this, it is preferable that the compounding quantity of the fluororesin in a composite resin composition is 10-70 mass% normally, and it is preferable that electroconductive particle is 0.5-5.0 mass% normally. I understand.

The outer surface of the surface layer 11 (or at least the outermost layer in the case of a plurality of layers) preferably has a surface resistivity of 10 ⁴ Ω / □ to 10 ¹² Ω / □. Specifically, the fixing belt is preferably 10 ⁴ Ω / □ to 10 ⁶ Ω / □, and the transfer belt is more preferably 10 ⁸ Ω / □ to 10 ¹² Ω / □. The surface resistivity of the surface layer 11 is measured according to JIS K6911 using a circular electrode (for example, “UR Probe” manufactured by Mitsubishi Oil Chemical Co., Ltd., Hiresta IP).

  In the present embodiment, the surface roughness Ra in the inner peripheral surface (inner surface) axial direction of the innermost layer of the surface layer 11 is preferably in the range of 0.5 μm to 3.0 μm, preferably 0.8 μm to The surface roughness Ra in the circumferential direction of the inner peripheral surface is more preferably in the range of 0.01 μm to 0.5 μm, and is preferably in the range of 0.01 μm to 0.3 μm. More preferably within the range

  In the present embodiment, the surface roughness Ra on the outer peripheral surface (outer surface) of the outermost layer of the surface layer 11 is smaller than the surface roughness Ra on the inner peripheral surface (inner surface) of the innermost layer. This is preferable in terms of suppressing motion noise.

[Endless Belt for Image Forming Apparatus According to Second Embodiment]
FIG. 2A is a perspective view showing an endless belt for an image forming apparatus according to a second embodiment of the present invention (when it has a two-layer structure of a surface layer and a base material layer). 2B is a longitudinal sectional view of an endless belt for the image forming apparatus shown in FIG. 2A. 2C is a cross-sectional view of the endless belt for the image forming apparatus shown in FIG. 2A.

  As shown in FIGS. 2A to 2C, the endless belt 20 for the image forming apparatus according to the second embodiment is a single layer in which the endless belt 10 for the image forming apparatus according to the first embodiment is only a surface layer. Compared to the case of having a structure, the difference is that it has a two-layer structure of a surface layer and a base material layer, but the other points are basically the same as in the case of the first embodiment. It is. Specifically, the endless belt 20 for an image forming apparatus according to the second embodiment is placed on a recording member in an image forming apparatus (not shown) that forms an image on a recording member (not shown). An endless belt 20 for an image forming apparatus that is used as a fixing belt or an intermediate transfer belt for fixing or transferring an unfixed image or an untransferred image on the substrate, and has a cylindrical substrate layer 22, and the substrate layer 22 There is a cylindrical surface layer 21 that contacts the recording member at the time of fixing or transferring (in other words, the base material layer 22 is provided on the back side of the surface layer 21), and at least the outer surface of the surface layer 21 is From a composite resin composition containing 25 to 89.5% by mass of a fluorinated polyimide resin having an ether group in the main chain, 10 to 70% by mass of a fluororesin, and 0.5 to 5.0% by mass of conductive particles. It is composed. Hereinafter, differences from the case of the first embodiment will be mainly described.

  The base material layer 22 used in the endless belt 20 for the image forming apparatus according to the second embodiment has a certain strength by separating the function from the surface layer 21 that requires releasability (releasability). Since the amount of the material used can be reduced while maintaining it, it is used to suppress an increase in cost when an expensive fluorinated polyimide resin is used. 2A to 2C, as described above, the case where a cylindrical material is used as the base material layer 22, for example, a cylindrical shape such as a rectangular tube or an elliptical cylinder, or a columnar shape such as a circular column. Also good. Further, as in the case of the surface layer 21, the base material layer 22 itself may be a plurality of layers. The thickness of the base material layer 22 is preferably 10 μm to 100 μm, and more preferably 20 μm to 80 μm. If it is less than 10 μm, the strength may be insufficient, and if it exceeds 100 μm, the flexibility may be insufficient.

  The base material layer 22 used in the endless belt 20 for the image forming apparatus according to the second embodiment is a conductive base material layer having conductivity, in order to release accumulated charges and to be semiconductive. It is preferable because the thickness of the surface layer can be reduced.

  In this case, the conductive base material layer is composed of polyimide (PI) in which conductive particles such as carbon black and ITO are dispersed. From the viewpoints of strength and conductivity control of the base material and cost. To preferred.

  Further, the conductive base material layer may be made of a metal.

  Moreover, it is preferable from an adhesive point that at least the inner surface of the base material layer 22 (which has the same meaning as the outer surface of the surface layer 21) is made of polyimide or polyamide.

  As in the case of the first embodiment, conductive particles are dispersed in the surface layer 21. In particular, the endless belt of the present embodiment is used as a transfer belt (transfer body, transfer (contact charging) film). When used as a charged body utilizing such an electrostatic force, it is preferable to disperse conductive particles in the base material layer 22 in the same manner as the surface layer 21. That is, it is preferable that conductive particles are dispersed in the polyimide or polyamide constituting the base material layer 22 described above.

Examples of the conductive particles include carbon black, carbon beads obtained by granulating carbon black, carbon fibers, carbon-based materials such as graphite, metals or alloys such as copper, silver, and aluminum, tin oxide, indium oxide, antimony oxide, Examples thereof include conductive metal oxides such as SnO ₂ —In ₂ O ₃ composite oxide, and conductive whiskers such as potassium titanate. Among these, carbon black is preferable from the viewpoint that predetermined conductivity can be obtained with a small addition amount.

  In the second embodiment, the surface roughness Ra in the inner surface axial direction of the base material layer 22 is preferably in the range of 0.5 μm to 3.0 μm, and in the range of 0.8 μm to 2.5 μm. Further, the surface roughness Ra in the inner surface circumferential direction is preferably in the range of 0.01 μm to 0.5 μm, and is preferably in the range of 0.01 μm to 0.3 μm. Is more preferable.

  In the present embodiment, the surface roughness Ra on the outer surface of the surface layer 21 is preferably smaller than the surface roughness Ra on the inner surface of the base material layer 22 from the viewpoint of suppressing sliding noise.

[Endless Belt for Image Forming Apparatus According to Third Embodiment]
FIG. 3A is a perspective view showing an endless belt (when it has a three-layer structure of a surface layer, an intermediate layer, and a base material layer) for an image forming apparatus according to a third embodiment of the present invention. 3B is a longitudinal sectional view of an endless belt for the image forming apparatus shown in FIG. 3A. 3C is a cross-sectional view of an endless belt for the image forming apparatus shown in FIG. 3A.

  As shown in FIGS. 3A to 3C, an endless belt 30 for an image forming apparatus according to the third embodiment has an endless belt 20 for the image forming apparatus according to the second embodiment having a two-layer structure. Compared to the case of the above, the first and second implementations are basically different in that the surface layer, the intermediate layer (elastic layer), and the base material layer have a three-layer structure. This is the same as the case of the form. Specifically, the endless belt 30 for the image forming apparatus according to the third embodiment is formed on the recording member in an image forming apparatus (not shown) that forms an image on the recording member (not shown). An endless belt 30 for an image forming apparatus that is used as a fixing belt or an intermediate transfer belt for fixing or transferring an unfixed image or an untransferred image on the substrate. A cylindrical surface layer 31 that contacts the recording member at the time of fixing or transferring is provided (in other words, the base material layer 32 is provided on the back side of the surface layer 31). Between the material layer 32, an elastic layer 33 is further provided as an intermediate layer, and at least the outer surface of the surface layer 31 includes 25 to 89.5% by mass of a fluorinated polyimide resin having an ether group in the main chain, and a fluororesin 10-70% by mass and conductive particles 0. It is made is composed of a composite resin composition comprising a 5.0% by weight. Hereinafter, differences from the first and second embodiments will be mainly described.

The intermediate layer (elastic layer) 33 used in the endless belt 30 for the image forming apparatus according to the third embodiment has conductivity as in the case of the conductive base material layer in the second embodiment. It is preferably a conductive intermediate layer, and the thickness of the surface layer 31 is reduced by separating the function from the surface layer 31 that requires releasability (releasability) and the base material layer 32 that requires strength. Even if it is set or thinned due to wear or the like, it is possible to maintain predetermined conductivity while maintaining releasability, and the amount of material used for the surface layer 31 can be reduced. Therefore, an increase in cost can be suppressed when an expensive fluorinated polyimide resin is used as the surface layer 31. In addition, about the means to provide electroconductivity to the intermediate | middle layer 33, it is the same as that of the case of the electroconductive base material layer in 2nd Embodiment. That is, the conductive intermediate layer is preferably composed of polyimide (PI) in which conductive particles such as carbon black are dispersed, and the conductive intermediate layer is composed of metal. It is preferable.
Used to improve the fixability to thick paper.

  3A to 3C, as described above, a case where a cylindrical member is used as the intermediate layer (elastic layer) 33 is shown. However, for example, a cylindrical shape such as a rectangular tube or an elliptical cylinder, or a columnar shape such as a circular column. It may be. Similarly to the case of the surface layer 31, the intermediate layer (elastic layer) 33 itself may be a plurality of layers.

  The intermediate layer (elastic layer) 33 is preferably, for example, silicone rubber or fluororubber from the viewpoints of heat resistance, cost, and the like.

[Support]
FIG. 4 is a perspective view showing a state in which the endless belt for the image forming apparatus according to the first embodiment shown in FIG. 1A is supported by a support.

  The support 50 is used to support the endless belt when manufacturing or using the endless belt for the image forming apparatus according to the present embodiment.

  Examples of the shape of the support 50 include a columnar shape such as a columnar shape or a cylindrical shape such as a cylindrical shape. In general, the cross section is preferably a circular one as described above, but may have another cross section such as an ellipse. Although there is no restriction | limiting in particular as thickness of the support body 50, For example, 0.3 mm-3 mm are preferable and 0.3 mm-1 mm are more preferable. In the present embodiment, the “support 50 surface” means the outer surface of the support 50 when the support 50 is cylindrical, unless otherwise specified. When it is columnar, it means a surface parallel to the axial direction of the column.

  The material of the support 50 is preferably a metal such as aluminum, copper, or stainless steel. In this case, in order to improve the peelability of the surface of the support 50, the surface of the support 50 is plated with chromium or nickel, the surface of the support 50 is coated with a fluororesin or silicone resin, or the surface of the support 50 is separated. A mold may be applied.

  On the other hand, when manufacturing an endless belt for an image forming apparatus according to the present embodiment, which will be described later, a coating film of the composite resin composition precursor dispersion is formed on the surface of the support 50 and the formed coating film is heated. In this case, the resulting composite resin composition film may be swollen or defective due to the gas generated by the evaporation of the solvent remaining in the film. From this, in order to effectively release the gas generated in the coating film when the heat treatment is performed, the surface of the support 50 is subjected to blasting so that A rough surface with a roughness Ra of about 0.8 to 1.0 μm may be formed, or cutting may be performed in the circumferential direction of the surface of the support 50.

  By performing cutting in the circumferential direction of the surface of the support 50, the above-described gas venting performance is secured, and the surface roughness Ra in the inner surface circumferential direction of the endless belt is set to the surface roughness in the inner surface axial direction. It can be made smaller than Ra.

  “Cutting is performed in the circumferential direction” means only a state in which the direction of the processing marks formed on the surface of the support 50 by cutting is substantially parallel to the circumferential direction of the support 50. It means not only that, but also includes a state formed slightly oblique to the circumferential direction. Further, the processing marks formed on the surface of the support 50 may be only those having a substantially constant angle with respect to the circumferential direction, or may be a mixture of those having a plurality of angles.

  In order to ensure the gas venting performance and to make the surface roughness Ra in the inner surface circumferential direction of the produced endless belt smaller than the inner surface axial direction of the endless belt, the axial direction of the surface of the support 50 Surface roughness Ra is in the range of 0.5 μm to 2.5 μm, and the surface roughness Ra in the circumferential direction of the surface of the support 50 is smaller than the surface roughness Ra in the axial direction of the surface of the support 50. Thus, it is preferable that a cutting process is given to the circumferential direction of the support body 50 surface.

  The surface roughness Ra in the circumferential direction of the surface of the support 50 is not particularly limited as long as it is smaller than the surface roughness Ra in the axial direction of the surface of the support 50, but it is 0.5 μm or less in the electrophotographic apparatus. In this case, the load (torque) during rotation of the endless belt is preferably reduced. The surface roughness Ra is an arithmetic average roughness which is one of the roughness measures, and a known stylus type surface roughness Ra measuring instrument (for example, Surfcom 1400A, manufactured by Tokyo Seimitsu Co., Ltd.) is used. Can be measured.

[Method for producing endless belt for image forming apparatus]
The method for producing an endless belt for an image forming apparatus according to the present embodiment includes an acid anhydride in which at least a part thereof is fluorinated as a precursor of a fluorinated polyimide resin having an ether group in the main chain, and at least a part thereof. As a precursor of a composite resin composition, a fluororesin and conductive particles are dispersed in a solution of a fluorinated polyamic acid synthesized from a fluorinated diamine (for example, an N-methylpyrrolidone solution). A dispersion liquid (varnish) is prepared, and a dispersion liquid (varnish) as a precursor of the obtained composite resin composition is applied to a base material layer or a support to form a coating film (hereinafter referred to as “composite resin composition”). A precursor precursor dispersion coating film forming step ”, and the formed coating film is heated to form a composite resin composition coating film constituting at least the outer surface of the surface layer (hereinafter referred to as“ a precursor precursor coating film forming step ”). ,"composite Including fat composition coating the sometimes abbreviated as (surface layer) formation process "). In addition to the above steps, other steps such as a drying step of the composite resin composition precursor dispersion coating film may be included as necessary.

  The method for producing an endless belt for an image forming apparatus according to the present embodiment can be broadly divided into a single layer in which the endless belt is only a surface layer 11 made of a composite resin composition, as in the first embodiment. When it has a structure (when a single film (surface layer) of the composite resin composition is directly formed on the metal support 50), and in the case of the second or third embodiment, it is endless. When the belt has a two-layer structure or a three-layer structure (for example, an endless belt made of an existing polyimide is coated with a composite resin composition precursor dispersion to form an endless belt having a plurality of layers. To be described separately.

<When the endless belt has a single-layer structure consisting only of the surface layer of the composite resin composition>
(Composite resin composition precursor dispersion coating film forming step)
In the composite resin composition precursor dispersion coating film forming step, a dispersion liquid (varnish) as a precursor of the composite resin composition is used to form a coating film on the surface of the support 50. As the fluorinated polyimide precursor having an ether group in the main chain, an acid anhydride which is represented by the above chemical formulas (1) to (3) and at least a part of which is fluorinated, and the above chemical formula (4) Specifically, a fluorinated polyamic acid synthesized from a diamine that is at least partially fluorinated represented by the above chemical formulas (5) to (15) is used. In addition, diamine is so preferable that a fluorination rate is high. In addition, as a solvent for dissolving a fluorinated polyamic acid (fluorinated PI precursor) having an ether group in the main chain (this solvent also functions as a dispersion medium for the fluororesin and conductive particles), N-methylpyrrolidone , N, N-dimethylacetamide, acetamide, N, N-dimethylformamide and the like, known aprotic polar solvents can be used. The concentration, viscosity, etc. of the fluorinated PI precursor solution should be appropriately selected so that the blended amount of the fluorinated polyimide resin in the finally obtained composite resin composition is 25 to 89.5% by mass. Can do. Next, a fluororesin and conductive particles are dispersed in the fluorinated PI precursor solution using a disperser to prepare a composite resin composition precursor dispersion.

  As a method for applying the composite resin composition precursor dispersion on the surface of the support 50, dip coating is performed by immersing the support 50 in the composite resin composition precursor dispersion and pulling it up, depending on the shape of the support 50. The composite resin composition precursor is installed on the surface of the support 50 which is installed so that the axial direction is substantially parallel to the horizontal direction and is rotated in the circumferential direction, from a nozzle or the like installed almost directly above the support 50. A flow coating method in which the support 50 or nozzle is translated in the axial direction while discharging the dispersion, and a blade coating method in which the coating film formed on the surface of the support 50 is metalized with a blade in this flow coating method. Can be used. In the above flow coating method and blade coating method, the coating film formed on the surface of the support 50 is formed in a spiral shape in the axial direction of the support 50, so that a seam can be formed, but the composite resin composition precursor dispersion Since the solvent contained in the liquid is slow to dry at room temperature, the seam is naturally smoothed.

(Drying step of composite resin composition precursor dispersion coating film)
In the drying step of the composite resin composition precursor dispersion coating film, it is preferable to remove the solvent contained in the coating film formed on the surface of the support 50 by heating and drying. The heating temperature is preferably not higher than the boiling point of the solvent to be used. For example, when the solvent is N-methylpyrrolidone (NMP, boiling point 202 ° C.), the range is preferably 70 to 201 ° C., and the solvent is dimethylacetamide (DMAC, boiling point 165 ° C. ), A range of 60 ° C. to 164 ° C. is preferable. More preferably, after heating at 60 ° C. to 125 ° C., which is 125 ° C. or less at which imidation starts, to remove water that adversely affects fluorination dissolved in the solvent, heating is performed at a temperature below the boiling point of the solvent. It is preferred to remove the solvent by step heating. As the temperature of the second stage, for example, when the solvent is N-methylpyrrolidone (NMP, boiling point 202 ° C.), a range of 125 ° C. to 201 ° C. is preferable, and the solvent is dimethylacetamide (DMAC, boiling point 165 ° C.). In some cases, a range of 125 ° C to 164 ° C is preferred. The heating time varies depending on the concentration and film thickness of the applied coating film, but the heating time at each stage is preferably about 10 to 120 minutes. When the coating film formed on the surface of the support 50 is dripped due to the influence of gravity during drying, the support 50 may be heated and dried while rotating at about 10 to 60 rpm with the axial direction horizontal. preferable.

(Composite resin composition film (surface layer) formation process)
Formation of the composite resin composition film by heating of the coating film dried through the drying step of the composite resin composition precursor dispersion coating film is performed at a temperature range from the boiling point of the solvent to about 400 ° C. to 20 to 120 ° C. It is preferable to carry out in about minutes. At that time, it is preferable that the temperature is increased stepwise or slowly at a constant speed until the above temperature is reached, and more preferably, heating and film formation are performed at two or three stages of temperature. In addition, since a firm film | membrane is formed, the one where final temperature is higher, it is preferable to heat at 340 degreeC or more. Next, the endless belt 10 is obtained by peeling the composite resin composition film (surface layer 11) formed on the surface of the support 50 through the above heat treatment from the support 50. The endless belt 10 thus obtained may be further subjected to end slit processing, punching drilling processing, tape winding processing, and the like as necessary.

<When the endless belt has a two-layer structure of a surface layer and a base material layer>
(PI precursor coating film forming process)
In the PI precursor coating film forming step, a polyimide precursor solution is used to form a coating film on the surface of the support 50. As the PI precursor contained in the polyimide precursor solution, a known one can be used. As the solvent for dissolving the PI precursor, known aprotic polar solvents such as N-methylpyrrolidone, N, N-dimethylacetamide, acetamide, N, N-dimethylformamide, and the like can be used. The concentration, viscosity, etc. of the PI precursor solution can be selected as appropriate, and other materials such as conductive particles, additives, etc. can be added to the PI precursor solution as necessary. Good.

  As a method for applying the PI precursor solution to the surface of the support 50, although depending on the shape of the support 50, a dip coating method in which the support 50 is immersed in the PI precursor solution and pulled up, the axial direction is in the horizontal direction. While the PI precursor solution is discharged from the nozzle or the like installed almost directly above the support 50 on the surface of the support 50 that is installed so as to be substantially parallel and rotates in the circumferential direction, A known method such as a flow coating method in which the nozzle is translated in the axial direction and a blade coating method in which the coating film formed on the surface of the support 50 is metalized with a blade can be used. In the flow coating method and the blade coating method, since the coating film formed on the surface of the support 50 is formed in a spiral shape in the axial direction of the support 50, a seam can be formed, but it is included in the PI precursor solution. Since the solvent is slow to dry at room temperature, the seam is naturally smoothed.

(PI precursor drying step)
In the PI precursor drying step, it is preferable to remove the solvent contained in the coating film formed on the surface of the support 50 as described above by heating and drying. The heating temperature is preferably equal to or lower than the boiling point of the solvent used. For example, when the solvent is N-methylpyrrolidone (NMP, boiling point 202 ° C.), the range is preferably 70 to 201 ° C., and the solvent is dimethylacetamide (DMAC, boiling point 165 In the case of (° C.), a range of 60 ° C. to 164 ° C. is preferable. More preferably, after heating once at 60 ° C. to 125 ° C., which is 125 ° C. or less at which imidation starts, and removing water that adversely affects fluorination dissolved in the solvent, heating is performed at a temperature below the boiling point of the solvent. It is preferred to remove the solvent by step heating. As the temperature of the second stage, for example, when the solvent is N-methylpyrrolidone (NMP, boiling point 202 ° C.), a range of 125 ° C. to 201 ° C. is preferable, and the solvent is dimethylacetamide (DMAC, boiling point 165 ° C.). In some cases, a range of 125 ° C to 164 ° C is preferred. Although the heating time varies depending on the concentration and film thickness of the applied coating film, the heating time at each stage is preferably about 10 to 120 minutes. When the coating film formed on the surface of the support 50 is dripped due to the influence of gravity during drying, the support 50 may be heated and dried while rotating at about 10 to 60 rpm with the axial direction horizontal. preferable.

(PI resin film (base material layer) formation process)
Formation of the PI resin film (base material layer 22) by heating the coating film dried through the PI precursor drying step is carried out in the temperature range from the boiling point of the solvent to about 400 ° C. for about 20 to 120 minutes. It is preferable to do. At that time, it is preferable that the temperature is increased stepwise or slowly at a constant speed until the above temperature is reached, and more preferably, heating and film formation are performed at two or three stages of temperature. In addition, since a firm film | membrane is formed when the final temperature is higher, it is preferable to heat at 340 degreeC or more. In this case, it is preferable that the base material layer is made a conductive base material layer using a polyimide precursor to which carbon black is added. In addition to using a polyimide precursor solution to which conductive fine particles are added, a conductive intermediate layer may be formed by forming a metal layer using electroless plating.

(Composite resin composition precursor dispersion coating film forming step)
Next, a composite resin composition precursor dispersion coating film is formed on the surface of the PI resin film (base material layer 22). As the fluorinated polyimide precursor having an ether group in the main chain, an acid anhydride in which at least a part thereof is represented by the above chemical formulas (1) to (3) and the above chemical formula (5) to (5) A fluorinated polyamic acid synthesized from a diamine that is at least partially fluorinated represented by (15) is used. In addition, diamine is so preferable that a fluorination rate is high. As a solvent for dissolving the fluorinated PI precursor, a known aprotic polar solvent such as N-methylpyrrolidone, N, N-dimethylacetamide, acetamide, N, N-dimethylformamide or the like can be used. The concentration, viscosity, etc. of the fluorinated PI precursor solution can be appropriately selected as described above. Next, a fluororesin and conductive particles are dispersed in the fluorinated PI precursor solution using a disperser to prepare a composite resin composition precursor dispersion.

  As a method for applying the composite resin composition precursor dispersion on the surface of the PI film (base material layer 22), the PI resin is installed such that the axial direction is substantially parallel to the horizontal direction and is rotated in the circumferential direction. While discharging the composite resin composition precursor dispersion from a nozzle or the like placed almost directly above the PI resin film (base material layer 22) on the surface of the film (base material layer 22), the PI resin film (base material) Layer 22) or a flow coating method in which the nozzle is translated in the axial direction, and in this flow coating method, a blade coating method in which a coating film formed on the surface of the PI resin film (base material layer 22) is metalized with a blade. Can be used.

(Composite resin composition precursor dispersion coating film drying step)
In the composite resin composition precursor dispersion coating film drying step, it is preferable to remove the solvent contained in the coating film formed on the surface of the PI film by heating and drying as described above. The heating temperature is preferably equal to or lower than the boiling point of the solvent used. For example, when the solvent is N-methylpyrrolidone (NMP, boiling point 202 ° C.), the range is preferably 70 to 201 ° C., and the solvent is dimethylacetamide (DMAC, boiling point 165 In the case of (C), a range of 60C to 164C is preferable. More preferably, after heating at 60 ° C. to 125 ° C., which is 125 ° C. or less at which imidation starts, to remove water that adversely affects fluorination dissolved in the solvent, heating is performed at a temperature below the boiling point of the solvent. It is preferred to remove the solvent by step heating. As the temperature of the second stage, for example, when the solvent is N-methylpyrrolidone (NMP, boiling point 202 ° C.), a range of 125 ° C. to 201 ° C. is preferable, and the solvent is dimethylacetamide (DMAC, boiling point 165 ° C.). In some cases, a range of 125 ° C to 164 ° C is preferred. Although the heating time varies depending on the concentration and film thickness of the applied coating film, the heating time at each stage is preferably about 10 to 120 minutes. When the coating film formed on the surface of the support 50 is dripped due to the influence of gravity during drying, the support 50 may be heated and dried while rotating at about 10 to 60 rpm with the axial direction horizontal. preferable.

(Composite resin composition film (surface layer) formation process)
Formation of the composite resin composition film (surface layer 21) by heating the coating film dried through the composite resin composition precursor dispersion coating film drying step described above is a temperature range from the boiling point of the solvent to about 400 ° C. It is preferable to carry out in about 20 to 120 minutes. At that time, it is preferable that the temperature is increased stepwise or slowly at a constant speed until the above temperature is reached, and more preferably, heating and film formation are performed at two or three stages of temperature. In addition, since a firm film | membrane is formed, the one where final temperature is higher, it is preferable to heat at 340 degreeC or more. Next, the PI resin film (base material layer 22) and the composite resin composition film (surface layer 21) formed on the surface of the support 50 through the above-described heat treatment are peeled from the support 50 to thereby endless belt 20. Get. The endless belt 20 obtained in this way may be further subjected to slit processing, punching drilling processing, tape winding processing, or the like as necessary.

<When the endless belt has a three-layer structure of a surface layer, an intermediate layer, and a base material layer>
Basically, it is the same as “when the endless belt has a two-layer structure of the surface layer and the base material layer” except that the “forming step of the elastic layer 33” described later is added. That is, “PI resin film (base material layer) forming step” and “composite resin composition precursor dispersion coating film forming step” in “when the endless belt has a two-layer structure of a surface layer and a base material layer” The following “elastic layer forming step” is performed between the “composite resin composition film (surface layer) forming step”.

(Formation process of intermediate layer (elastic layer))
After applying an adhesive layer for imparting adhesiveness to the surface of the PI resin film (base material layer) 32, a fluororubber solution was applied and air-dried, followed by vulcanization at 230 ° C. for 4 hours for a total of 180 μm. These fluororubber layers are laminated to form an intermediate layer (elastic layer) 33. The intermediate layer obtained (a precursor coating of a fluorine-containing aromatic ether ketone polymer on the surface of the elastic layer 33 is formed and heated to form a composite resin composition coating (surface layer 31), and finally In this case, the conductive intermediate layer 33 is formed on the surface of the PI resin film (base material layer) 32 by applying and baking a polyimide precursor solution to which conductive fine particles are added. In addition to using a polyimide precursor solution to which conductive fine particles are added, a conductive intermediate layer may be formed by forming a metal layer using electroless plating.

[Image forming apparatus]
Next, an image forming apparatus using the endless belt of the present embodiment will be described. The image forming apparatus according to the present embodiment may be any known image forming apparatus that can use the endless belt according to the present embodiment. Specifically, as an example, an image fixing apparatus having the following configuration will be described below. That is, the image forming apparatus (image fixing apparatus) according to the present embodiment includes at least one or more driving members, an endless belt that can be driven and rotated by the one or more driving members, and a pressing member. The driving member surface and the outer peripheral surface of the endless belt are disposed in contact with the inner peripheral surface of the endless belt, and the pressure contact portion (nip) is pressed by a pressing member that presses the outer peripheral surface of the endless belt against the driving member surface. In an image fixing apparatus that fixes an unfixed toner image on the surface of a recording sheet by heating the recording sheet that holds the unfixed toner image on the surface of the recording sheet and heating the recording sheet. It has a configuration using the endless belt of the embodiment.

  Since the image fixing apparatus according to the present embodiment uses the endless belt according to the present embodiment, the load torque of the driving member can be kept low, durability against high-speed rotation can be improved, and noise can be reduced. Note that the image fixing apparatus of the present invention may have other configurations and functions as necessary in addition to the configurations and functions as described above. For example, a lubricant may be applied to the inner peripheral surface of the endless belt. As the lubricant, a known liquid lubricant (for example, silicone oil) can be used. The lubricant can be continuously supplied via a felt or the like provided in contact with the inner peripheral surface of the endless belt.

  In the image fixing device of the present embodiment, it is preferable that the pressure distribution in the endless belt axial direction of the nip portion can be adjusted by the pressing member. For example, when a lubricant is used, the presence of the lubricant applied to the inner peripheral surface, such as bringing the lubricant to one end of the endless belt or collecting it at the center, is adjusted by adjusting the pressure distribution. Can be controlled. For this reason, for example, excess lubricant can be collected and collected at one end of the endless belt, or the lubricant can be moved to the center of the endless belt. Can prevent contamination in the device.

  Such adjustment of the pressure distribution is particularly useful when the lubricant is used and the above-described streak roughness is given to the inner peripheral surface of the endless belt to be further used. In this case, it is easier to control the presence state of the lubricant applied to the inner peripheral surface by adjusting the pressure distribution in the nip portion in consideration of the direction of the streaky roughness.

  Hereinafter, the endless belt for an image forming apparatus of the present invention and the manufacturing method thereof will be described more specifically with reference to examples. Note that the present invention is not limited in any way by the following examples.

  Here, Examples 1 to 5 are endless belts having a single-layer structure with only a surface layer, and Example 6 is Example 7 in the case of an endless belt having a two-layer structure of a surface layer and a base material layer. In the case of an endless belt having a three-layer structure of a surface layer, an intermediate layer and a base material layer, Comparative Examples 1 and 2 are compared when a resin having no ether group in the main chain is used as a fluorinated polyimide resin. In Examples 3 to 4, when the amount of partially fluorinated polyamic acid that is a fluorinated polyimide resin having an ether group in the main chain is blended outside the specified range, Comparative Examples 5 to 6 specify the fluororesin and conductive particles. When blended in an external blending amount, Examples 8 to 12 are examples 13 in the case of an endless belt having a single-layer structure having only a surface layer when cross-linked PTFE is used as the fluororesin constituting the composite resin composition. Are the constituents of the composite resin composition. In the case of an endless belt having a two-layer structure of a surface layer and a base material layer when cross-linked PTFE is used as the base resin, Examples 14 to 18 have a two-layer structure of a surface layer and a conductive base material layer. In the case of an endless belt, and Examples 19 and 20 show the case of an endless belt having a three-layer structure of a surface layer, a conductive intermediate layer, and a base material layer, respectively.

Example 1
Application | coating of the dispersion liquid (varnish) as a precursor of the composite resin composition to the support body 50 surface was implemented as follows using the flow coat apparatus. As a composite resin composition precursor dispersion (varnish), N-methylpyrrolidone as a solvent, an acid anhydride (10FEDA: 1,4-bis (3,4-dicarboxyl) represented by the above chemical formula (2) Trifluorophenoxy) tetrafluorobenzene dianhydride) and the aromatic diamine (6FBAPP: 2,2-bis (p- (p-aminophenoxy) phenyl-1,1,1,) represented by the above chemical formula (15) Polytetrafluoroethylene (PTFE) having an average particle size of 0.2 μm in a solution of partially fluorinated polyamic acid obtained by dissolving 69% by mass of partially fluorinated polyamic acid synthesized from 3,3,3-hexafluoropropane) 30% by mass of particles and 1% by mass of Ketjen Black (EC600JD: manufactured by Ketjen Black International) are dispersed. A dispersion liquid (varnish) was used, and as the support 50, an aluminum cylinder having an outer diameter of 30 mm and a length of 500 mm was used, and this surface was cut in the circumferential direction to obtain the surface of the support 50 surface. A surface roughness Ra of 2.0 μm in the axial direction and 0.3 μm in the circumferential direction was prepared, and a silicone mold release agent (trade name: KS700, manufactured by Shin-Etsu Chemical Co., Ltd.) was provided on the surface of the support 50. Then, baking treatment was performed for 1 hour at 300 ° C. Next, a dispersion (varnish) as a precursor of the composite resin composition was applied to the surface of the support 50 using a flow coat apparatus. Then, a heating film was formed using a nitrogen-substituted heating furnace (inert oven), after heating at 120 ° C. for 30 minutes, then at 200 ° C. for 30 minutes, at 250 ° C. for 30 minutes, and finally at 380 ° C. Method of heating for 30 minutes The composite resin composition film was formed on the surface of the support 50. After cooling to room temperature, the composite resin composition film was peeled off, and the belt film thickness was uniform as 50 μm and consisted of a single layer of the composite resin composition having no defects. An endless belt was obtained, and a release agent was applied to the surface of the support 50 in advance, so that the inner peripheral surface of the endless belt did not adhere to the support 50 during peeling.

(Example 2)
As a fluorinated PI precursor having an ether group in the main chain, an acid anhydride (6FDA: 2,2-bis (3,4-anhydrodicarboxyphenyl) -hexafluoropropane represented by the above chemical formula (3) ) And the aromatic diamine represented by the above chemical formula (15) (6FBAPP: 2,2-bis (p- (p-aminophenoxy) phenyl-1,1,1,3,3,3-hexafluoropropane) An endless belt made of a single layer of partially fluorinated polyimide having no defects was obtained in the same manner as in Example 1 except that the partially fluorinated polyamic acid synthesized from the above was used.

(Example 3)
As a fluorinated PI precursor, an acid anhydride represented by the above chemical formula (2) (10FEDA: 1,4-bis (3,4-dicarboxytrifluorophenoxy) tetrafluorobenzene dianhydride) and the above chemical formula Except for using a fully fluorinated polyamic acid synthesized from the aromatic diamine represented by (6) (6FMDA: 4,4 ′-(hexafluoroisopropylidene) dianiline), the same as Example 1 Thus, an endless belt made of a single layer of fully fluorinated polyimide having no defect was obtained.

Example 4
As a fluorinated PI precursor, an acid anhydride represented by the above chemical formula (2) (10FEDA: 1,4-bis (3,4-dicarboxytrifluorophenoxy) tetrafluorobenzene dianhydride) and the above chemical formula Example 1 except that a partially fluorinated polyamic acid synthesized from an aromatic diamine represented by (9) (13FPD: 1,4-diamino-2-tridecafluoro-n-hexylbenzene) was used. In the same manner as above, an endless belt composed of a single layer of partially fluorinated polyimide having no defect was obtained.

(Example 5)
As a fluorinated PI precursor, an acid anhydride represented by the above chemical formula (1) (P6FDA: 3,6-bis (trifluoromethyl) -1,2,4,5-benzenetetracarboxylic dianhydride) And an aromatic diamine represented by the above chemical formula (5) (8FODA: 2,2 ′, 3,3 ′, 5,5 ′, 6,6′-octafluoro-4,4′-diaminodiphenyl ether) An endless belt composed of a single layer of partially fluorinated polyimide having no defects was obtained in the same manner as in Example 1 except that the fully fluorinated polyamic acid thus obtained was used.

(Example 6)
After a solution containing the PI precursor on the surface of the support 50 is formed using a flow coat apparatus, a film is formed by heating to form a normal PI endless belt, and then a composite resin composition is further formed on the surface using a flow coat apparatus. An endless belt composed of two layers was obtained by applying a dispersion liquid (varnish) as a precursor and heating. Details will be described below. As the PI precursor solution, an N-methylpyrrolidone solution (trade name: U varnish, manufactured by Ube Industries, solid content concentration: 18%, viscosity: about 5 Pa · s) was used. Further, as the support 50, an aluminum cylinder having an outer diameter of 30 mm and a length of 500 mm is used, and by cutting the surface in the circumferential direction, the surface roughness Ra of the surface of the support 50 is in the axial direction. 2.0 μm and 0.3 μm in the circumferential direction were prepared. Further, a silicone mold release agent (trade name: KS700, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the surface of the support 50 and baked at 300 ° C. for 1 hour. Next, the N-methylpyrrolidone solution of the aforementioned PI precursor was applied to the surface of the support 50 using a flow coat apparatus. Next, heating film formation was performed using a heating furnace (inert oven) purged with nitrogen. After heating at 120 ° C. for 30 minutes, a PI resin film was formed on the surface of the support 50 by heating at 200 ° C. for 30 minutes, 250 ° C. for 30 minutes, and finally 340 ° C. for 30 minutes. After cooling to room temperature, the PI resin film was peeled off to obtain an endless belt consisting of a single layer of polyimide having a uniform belt film thickness of 50 μm and no defects. Next, the dispersion liquid (varnish) as a precursor of a composite resin composition was apply | coated to the surface which consists of a single layer of this polyimide using the same flow coat apparatus. As a precursor dispersion (varnish) of the composite resin composition, an acid anhydride (10FEDA: 1,4-bis (3,4-di) represented by the above chemical formula (2) is added to N-methylpyrrolidone as a solvent. Carboxytrifluorophenoxy) tetrafluorobenzene dianhydride) and aromatic diamine (6FBAPP: 2,2-bis (p- (p-aminophenoxy) phenyl-1,1,1) represented by the above chemical formula (15) , 3,3,3-hexafluoropropane) in a partially fluorinated polyamic acid solution containing 69% by mass of a partially fluorinated polyamic acid dissolved in polytetrafluoroethylene (PTFE) having an average particle size of 0.2 μm. ) Particles and ketjen black (EC600JD) 1% by mass dispersion (varnish) was used. The heating film was formed using the heating furnace (inert oven) which was heated at 120 ° C. for 30 minutes, then heated at 200 ° C. for 30 minutes, 250 ° C. for 30 minutes, and finally at 340 ° C. for 30 minutes. By this method, a composite resin composition film was formed on the surface of the support 50. After cooling to room temperature, the resin composed of two layers of PI resin and composite resin composition film was peeled off from the support 50, and the belt layer thickness was An endless belt composed of two layers coated with a 70 μm defect-free PI resin and a composite resin composition was obtained, and the adhesion between the PIs of each layer was strong and not peeled off, and the surface of the support 50 was previously separated from the mold Since the agent was applied, it was easy to peel the endless belt from the support 50.

(Comparative Example 1)
As the fluorinated PI precursor solution, an acid anhydride (6FDA: 2,2-bis (3,4-anhydrodicarboxyphenyl) -hexafluoropropane) represented by the above chemical formula (3) and the above chemical formula ( 5) Except for using an N-methylpyrrolidone solution of a partially fluorinated polyamic acid synthesized from an aromatic diamine represented by (TFDB: 2,2′-bis (trifluoromethyl) benzidine). In the same manner as in Example 1, an endless belt consisting of a single layer of fluorinated polyimide having no defects was obtained. However, this partially fluorinated polyimide film is rigid and lacks flexibility because it does not have an ether bond.

(Comparative Example 2)
The fluorinated PI precursor has the following chemical formula (16):

  An acid anhydride represented by the formula (NTCDA: naphthalene-1,4,5,8-tetracarboxylic dianhydride) and an aromatic diamine represented by the above chemical formula (4) (6FMDA: 2,2′-bis From a single layer of defect-free fluorinated polyimide in exactly the same manner as in Example 1, except that an N-methylpyrrolidone solution of partially fluorinated polyamic acid synthesized from (trifluoromethyl) benzidine) was used. A semiconductive endless belt was obtained. However, this partially fluorinated polyimide film is rigid and lacks flexibility because it does not have an ether bond.

(Comparative Example 3)
A single layer of only the surface layer of fluorinated polyimide having no defects in the same manner as in Example 1 except that the dissolved amount of the partially fluorinated polyamic acid is 20% by mass and the dispersed amount of the fluororesin is 79% by mass. A semiconductive endless belt having a structure was obtained.

(Comparative Example 4)
A single layer of only a surface layer of fluorinated polyimide having no defects in the same manner as in Example 1 except that the dissolved amount of the partially fluorinated polyamic acid is 92% by mass and the dispersed amount of the fluororesin is 7% by mass. A semiconductive endless belt having a structure was obtained.
(Comparative Example 5)
Except that the dissolved amount of the partially fluorinated polyamic acid was 64% by mass, and the carbon black was dispersed by 6% by mass of Ketjen Black (EC600JD: manufactured by Ketjen Black International Co., Ltd.). Thus, a semiconductive endless belt made of a single layer of fluorinated polyimide without defects was obtained.

(Comparative Example 6)
Example 1 except that the amount of partially fluorinated polyamic acid dissolved was 69.6% by mass, and carbon black was dispersed by 0.4% by mass of Ketjen Black (EC600JD: manufactured by Ketjen Black International). In the same manner, an endless belt made of a single layer of partially fluorinated polyimide having no defect was obtained.

(Example 7)
In Example 1, instead of polytetrafluoroethylene (PTFE) particles having an average particle diameter of 0.2 μm, the average particle diameter obtained by polymerizing the monomer in acetone solvent by irradiation with an electron beam is 0. An endless belt having a single-layer structure with only a surface layer of partially fluorinated polyimide having no defects was obtained in the same manner as in Example 1 except that 50% by mass of 2 μm crosslinked PTFE particles was used.

(Example 8)
As a fluorinated PI precursor having an ether group in the main chain, an acid anhydride (6FDA: 2,2-bis (3,4-anhydrodicarboxyphenyl) -hexafluoropropane represented by the above chemical formula (3) ) And the aromatic diamine represented by the above chemical formula (15) (6FBAPP: 2,2-bis (p- (p-aminophenoxy) phenyl-1,1,1,3,3,3-hexafluoropropane) An endless belt having a single-layer structure of only a surface layer of a partially fluorinated polyimide having no defect was obtained in the same manner as in Example 7 except that a partially fluorinated polyamic acid synthesized from was used.

Example 9
As a fluorinated PI precursor, an acid anhydride represented by the above chemical formula (2) (10FEDA: 1,4-bis (3,4-dicarboxytrifluorophenoxy) tetrafluorobenzene dianhydride) and the above chemical formula Except for using a fully fluorinated polyamic acid synthesized from an aromatic diamine represented by (6) (6FMDA: 4,4 ′-(hexafluoroisopropylidene) dianiline), the same as Example 7 Thus, an endless belt having a single-layer structure consisting of only a surface layer of fully fluorinated polyimide having no defect was obtained.

(Example 10)
As a fluorinated PI precursor, an acid anhydride represented by the above chemical formula (2) (10FEDA: 1,4-bis (3,4-dicarboxytrifluorophenoxy) tetrafluorobenzene dianhydride) and the above chemical formula Example 7 except that a partially fluorinated polyamic acid synthesized from an aromatic diamine represented by (9) (13FPD: 1,4-diamino-2-tridecafluoro-n-hexylbenzene) was used. In the same manner as above, an endless belt having a single layer structure of only a surface layer of partially fluorinated polyimide having no defect was obtained.

(Example 11)
As a fluorinated PI precursor, an acid anhydride represented by the above chemical formula (1) (P6FDA: 3,6-bis (trifluoromethyl) -1,2,4,5-benzenetetracarboxylic dianhydride) And an aromatic diamine represented by the above chemical formula (5) (8FODA: 2,2 ′, 3,3 ′, 5,5 ′, 6,6′-octafluoro-4,4′-diaminodiphenyl ether) Except for using the fully fluorinated polyamic acid thus obtained, an endless belt having a single layer structure of only the surface layer of partially fluorinated polyimide having no defect was obtained in the same manner as in Example 7.

(Example 12)
In Example 6, instead of polytetrafluoroethylene (PTFE) particles having an average particle diameter of 0.2 μm, the average particle diameter obtained by polymerizing the monomer in acetone solvent by irradiating with an electron beam is 0. Two layers of a surface layer and a base material layer coated with a defect-free PI resin and composite resin composition exactly as in Example 6 except that 50% by mass of 2 μm crosslinked PTFE particles were used An endless belt having a structure was obtained.

(Example 13)
A PI precursor solution containing conductive particles was applied to the surface of the support 50 using a flow coater, and then heated to form a conductive PI endless belt. Next, after applying a dispersion (varnish) as a precursor of the composite resin composition to the surface using a flow coater, the two-layer structure of the surface layer and the conductive substrate layer is heated. An endless belt having was obtained. Details will be described below.

  As a PI precursor solution containing conductive particles, an N-methylpyrrolidone solution of a PI precursor (trade name: U varnish, Ube Industries, solid content concentration: 18%, viscosity: about 5 Pa · s) A dispersion (varnish) in which 3% by mass of chain black (EC600JD: manufactured by Ketjen Black International) was dispersed was used. Further, as the support 50, an aluminum cylinder having an outer diameter of 30 mm and a length of 500 mm is used, and by cutting the surface in the circumferential direction, the surface roughness Ra of the surface of the support 50 is in the axial direction. 2.0 μm and 0.3 μm in the circumferential direction were prepared. Further, a silicone mold release agent (trade name: KS700, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the surface of the support 50 and baked at 300 ° C. for 1 hour. Next, the N-methylpyrrolidone solution of the PI precursor containing carbon black described above was applied to the surface of the support 50 using a flow coat apparatus. Next, heating film formation was performed using a heating furnace. After heating at 120 ° C. for 30 minutes, a PI resin film was formed on the surface of the support 50 by heating at 200 ° C. for 30 minutes, 250 ° C. for 30 minutes, and finally 340 ° C. for 30 minutes. After cooling to room temperature, the PI resin film was peeled off to obtain a conductive polyimide endless belt having a uniform belt film thickness of 50 μm and no defects. Next, the dispersion liquid (varnish) as a precursor of a composite resin composition was apply | coated to the surface of this polyimide using the same flow coat apparatus. As a precursor dispersion (varnish) of the composite resin composition, an acid anhydride (10FEDA: 1,4-bis (3,4-di) represented by the above chemical formula (2) is added to N-methylpyrrolidone as a solvent. Carboxytrifluorophenoxy) tetrafluorobenzene dianhydride) and aromatic diamine (6FBAPP: 2,2-bis (p- (p-aminophenoxy) phenyl-1,1,1) represented by the above chemical formula (15) , 3,3,3-hexafluoropropane) in a partially fluorinated polyamic acid solution containing 69% by mass of a partially fluorinated polyamic acid dissolved in polytetrafluoroethylene (PTFE) having an average particle size of 0.2 μm. ) Particles and ketjen black (EC600JD) 1% by mass dispersion (varnish) was used. The film was heated at 120 ° C. for 30 minutes, heated at 200 ° C. for 30 minutes, 250 ° C. for 30 minutes, and finally heated at 340 ° C. for 30 minutes. After cooling to room temperature, the resin composed of two layers of the PI resin and the composite resin composition film was peeled off from the support 50, and the surface layer having a defect with a belt layer thickness of 70 μm was formed. A conductive endless belt having a two-layer structure with a conductive base material layer was obtained, and the adhesion between PIs of each layer was strong and never peeled off, and a release agent was applied to the surface of the support 50 in advance. Therefore, the endless belt was easily peeled from the support 50.

(Example 14)
As a fluorinated PI precursor having an ether group in the main chain, an acid anhydride (6FDA: 2,2-bis (3,4-anhydrodicarboxyphenyl) -hexafluoropropane represented by the above chemical formula (3) ) And the aromatic diamine represented by the above chemical formula (15) (6FBAPP: 2,2-bis (p- (p-aminophenoxy) phenyl-1,1,1,3,3,3-hexafluoropropane) An endless belt having a two-layer structure of a surface layer having no defect and a conductive base material layer was obtained in the same manner as in Example 13 except that a partially fluorinated polyamic acid synthesized from was used.

(Example 15)
As a fluorinated PI precursor, an acid anhydride represented by the above chemical formula (2) (10FEDA: 1,4-bis (3,4-dicarboxytrifluorophenoxy) tetrafluorobenzene dianhydride) and the above chemical formula Except for using a fully fluorinated polyamic acid synthesized from an aromatic diamine represented by (6) (6FMDA: 4,4 ′-(hexafluoroisopropylidene) dianiline), the same as Example 13 Thus, an endless belt having a two-layer structure of a defect-free surface layer and a conductive base material layer was obtained.

(Example 16)
As a fluorinated PI precursor, an acid anhydride represented by the above chemical formula (2) (10FEDA: 1,4-bis (3,4-dicarboxytrifluorophenoxy) tetrafluorobenzene dianhydride) and the above chemical formula Example 13 except that a partially fluorinated polyamic acid synthesized from an aromatic diamine represented by (9) (13FPD: 1,4-diamino-2-tridecafluoro-n-hexylbenzene) was used. In the same manner as above, an endless belt having a two-layer structure of a surface layer having no defect and a conductive base material layer was obtained.

(Example 17)
As a fluorinated PI precursor, an acid anhydride represented by the above chemical formula (1) (P6FDA: 3,6-bis (trifluoromethyl) -1,2,4,5-benzenetetracarboxylic dianhydride) And an aromatic diamine represented by the above chemical formula (5) (8FODA: 2,2 ′, 3,3 ′, 5,5 ′, 6,6′-octafluoro-4,4′-diaminodiphenyl ether) An endless belt having a two-layer structure of a surface layer having no defects and a conductive substrate layer was obtained in the same manner as in Example 13 except that the fully fluorinated polyamic acid thus obtained was used.

(Example 18)
After the PI precursor is applied to the surface of the support 50 using a flow coat apparatus, the film is heated to form a normal PI endless belt, and then a solution containing the PI precursor containing conductive fine particles is flow-coated. After forming a conductive film by heating and forming a film to form a conductive substrate layer surface, a dispersion (varnish) as a precursor of a composite resin composition using a flow coater Was applied and heated to obtain an endless belt having a three-layer structure of a surface layer, a conductive intermediate layer, and a base material layer. Details will be described below.

  As the PI precursor solution, an N-methylpyrrolidone solution (trade name: U varnish, manufactured by Ube Industries, solid content concentration: 18%, viscosity: about 5 Pa · s) was used. Further, as the support 50, an aluminum cylinder having an outer diameter of 30 mm and a length of 500 mm is used, and by cutting the surface in the circumferential direction, the surface roughness Ra of the surface of the support 50 is in the axial direction. 2.0 μm and 0.3 μm in the circumferential direction were prepared. Further, a silicone mold release agent (trade name: KS700, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the surface of the support 50 and baked at 300 ° C. for 1 hour. Next, the N-methylpyrrolidone solution of the aforementioned PI precursor was applied to the surface of the support 50 using a flow coat apparatus. Next, heating film formation was performed using a heating furnace. After heating at 120 ° C. for 30 minutes, a PI resin film was formed on the surface of the support 50 by heating at 200 ° C. for 30 minutes, 250 ° C. for 30 minutes, and finally 340 ° C. for 30 minutes. After cooling to room temperature, the PI resin film was peeled off to obtain an endless belt consisting of a single layer of polyimide having a uniform belt film thickness of 50 μm and no defects. Next, a conductive film is formed on the surface of the polyimide single layer. The film was coated with a PI precursor solution containing conductive particles using the same flow coat apparatus and heated to form a conductive intermediate layer. As PI precursor solution containing conductive particles, N-methylpyrrolidone solution of PI precursor (trade name: U varnish, Ube Industries, solid content concentration: 18%, viscosity: about 5 Pa · s) A dispersion (varnish) in which 3% by mass of chain black (EC600JD: manufactured by Ketjen Black International) was dispersed was used. Next, the dispersion liquid (varnish) as a precursor of a composite resin composition was apply | coated to the surface which consists of two layers (a base material layer and an intermediate | middle layer) of this polyimide using the same flow coat apparatus. As a precursor dispersion (varnish) of the composite resin composition, an acid anhydride (10FEDA: 1,4-bis (3,4-di) represented by the above chemical formula (2) is added to N-methylpyrrolidone as a solvent. Carboxytrifluorophenoxy) tetrafluorobenzene dianhydride) and aromatic diamine (6FBAPP: 2,2-bis (p- (p-aminophenoxy) phenyl-1,1,1) represented by the above chemical formula (15) , 3,3,3-hexafluoropropane) in a partially fluorinated polyamic acid solution containing 69% by mass of a partially fluorinated polyamic acid dissolved in polytetrafluoroethylene (PTFE) having an average particle size of 0.2 μm. ) Particles and ketjen black (EC600JD) 1% by mass dispersion (varnish) was used. The film was heated at 120 ° C. for 30 minutes, heated at 200 ° C. for 30 minutes, 250 ° C. for 30 minutes, and finally heated at 340 ° C. for 30 minutes. A composite resin composition film (surface layer) was formed on the three-layer structure of the PI resin base material layer, the conductive PI layer conductive intermediate layer, and the composite resin composition film surface layer after cooling to room temperature. The endless belt having a three-layer structure of a defect-free surface layer, a conductive intermediate layer, and a base material layer having a belt layer thickness of 70 μm was obtained. Since the release agent was applied to the surface of the support 50 in advance, it was easy to peel the endless belt from the support 50.

(Example 19)
Three layers of a surface layer, a conductive intermediate layer, and a base layer are formed in the same manner as in Example 18 except that the conductive intermediate layer is made of metal instead of the PI layer in which conductive particles are dispersed. An endless belt having a structure was formed. For the formation of the metal layer, a 10 μm metal layer was formed using Ni electroless plating to form a conductive intermediate layer.

(Evaluation test)
An endless belt using each composite resin composition obtained in Examples 1 to 19 and an endless belt obtained in Comparative Examples 1 to 7 were used as pressure belts for fixing, respectively, as a color composite machine (trade name: DocuCenter C7600: Incorporated into a fixing device (made by Fuji Xerox Co., Ltd.), a durability test and an image quality evaluation were conducted by continuously feeding 200,000 sheets. In the fixing device incorporating the endless belts of Examples 1 to 19, good durability and image quality were obtained even after continuous feeding of 200,000 sheets. On the other hand, in the fixing devices incorporating the endless belts of Comparative Examples 1 to 2, 4 and 5, good durability was obtained even after continuous feeding of 200,000 sheets. A paper jam occurred in the back image with a large amount. For example, in the fixing device incorporating the endless belt of Comparative Example 4, the releasability at the time of fixing was insufficient, and a paper jam occurred on the third sheet. In the fixing device incorporating the endless belt of Comparative Example 5, the releasability at the time of fixing was insufficient, and a paper jam occurred on five sheets. Further, in the fixing device incorporating the endless belt of Comparative Example 6, the electric resistance was as high as 10 ¹⁴ Ω / □, and electrostatic offset occurred during fixing, and the image was distorted. From the initial stage, the 10th sheet was soiled, and good image quality could not be obtained over a long period of time. Also, the fixing device incorporating the endless belt of Comparative Example 3 had poor image quality and insufficient durability.

DESCRIPTION OF SYMBOLS 10 Endless belt 11 for image forming apparatuses Surface layer 20 Endless belt 21 for image forming apparatuses Surface layer 22 Base material layer 30 Endless belt 31 for image forming apparatuses Surface layer 32 Base material layer 33 Elastic layer (intermediate layer)
50 Support

Claims (14)

  It has a surface layer, and at least the outer surface of the surface layer has 25 to 89.5% by mass of fluorinated polyimide resin having an ether group in the main chain, 10 to 70% by mass of fluororesin, and conductive particles 0 An endless belt for an image forming apparatus comprising a composite resin composition containing 5 to 5.0% by mass.   The fluorinated polyimide resin having an ether group in the main chain is prepared from a fluorinated polyamic acid synthesized from an acid anhydride that is at least partially fluorinated and a diamine that is at least partially fluorinated. The endless belt for an image forming apparatus according to claim 1, wherein the endless belt is a resin. The acid anhydride having at least a part thereof fluorinated and the diamine having at least a part thereof having been fluorinated include a fluorine group (—F) and / or a perfluoroalkyl group (—C _n F _{2n + 1} : n is The endless belt for an image forming apparatus according to claim 2, having an integer of 1 or more. The acid anhydride, at least a part of which is fluorinated, has the following chemical formulas (1) to (3):



The diamines represented by the above and at least a part of which are fluorinated are represented by the following chemical formula (4):

The endless belt for an image forming apparatus according to claim 3, which is represented by: The diamines at least partially fluorinated are represented by the following chemical formulas (5) to (15).
The endless belt for an image forming apparatus according to claim 4, wherein










  The endless belt for an image forming apparatus according to claim 1, wherein the fluororesin has a particle size of 0.05 μm to 1.0 μm.   The endless belt for an image forming apparatus according to claim 1, wherein the fluororesin is a crosslinked polytetrafluoroethylene (PTFE) -containing fluororesin.   The cross-linked PTFE-containing fluororesin is composed of cross-linked PTFE alone, a resin composition of cross-linked PTFE and PTFE, or a resin composition of cross-linked PTFE and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) resin. The endless belt for an image forming apparatus according to claim 7, which is a fluororesin.   The endless belt for an image forming apparatus according to claim 7 or 8, wherein the crosslinked PTFE constituting the crosslinked PTFE-containing fluororesin is obtained by polymerizing a monomer in an acetone solvent by irradiation with an electron beam. .   A single-layer structure of only the surface layer, a two-layer structure of the surface layer and a base material layer formed so as to be in contact with the surface layer, or between the surface layer, the surface layer and the base material layer The endless belt for an image forming apparatus according to claim 1, wherein the endless belt has a three-layer structure including the formed intermediate layer and the base material layer.   In the case of having the two-layer structure or the three-layer structure, the base layer in the two-layer structure and the intermediate layer in the three-layer structure, which are formed so as to be in contact with the surface layer, are electrically conductive. The endless belt for an image forming apparatus according to claim 10, which is a base material layer and a conductive intermediate layer.   The endless belt for an image forming apparatus according to claim 11, wherein the conductive base material layer and the conductive intermediate layer are made of polyimide (PI) in which conductive particles are dispersed or a metal.   The endless belt for an image forming apparatus according to claim 12, wherein the conductive particles are carbon black.   An image forming apparatus using the endless belt for an image forming apparatus according to claim 1.