JP2008116632A - Endless belt, manufacturing method therefor, and image forming apparatus with endless belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endless belt in which peeling between a reinforcing layer and a base material is prevented and the occurrence of cracking of the reinforcing layer due to deformation is suppressed and to provide a manufacturing method for the endless belt and an image forming apparatus with the endless belt. <P>SOLUTION: The endless belt has the base material containing a filler and a resin, a projection provided at one end or both ends in the width direction of the base material on the inner circumferential surface side of the base material, and the reinforcing layer provided on the outer circumferential surface side of the base material at a position opposite to the projection through the base material, the reinforcing layer includes, as a main component, the resin comprising the same monomer as the monomer constituting the resin included in the base material as a main component, and the tensile yield strain in the peripheral direction of the reinforcing layer is larger than that in the peripheral direction of the base material. The manufacturing method for the endless belt and the image forming apparatus with the endless belt are provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an endless belt, a manufacturing method thereof, and an image forming apparatus including the endless belt.

When using a transfer belt or a transfer fixing belt in an image forming apparatus, in order to prevent meandering while the belt is running, a protrusion having a certain thickness called a protrusion is attached to the end in the width direction of the belt, A method is adopted in which the projection is fitted into a groove formed near the end of the driving roll or the vicinity of the end of the roll.
In the case of a system that drives while preventing the meandering by forming a protrusion at the belt end, a film thickness difference occurs between the protrusion forming part and the belt base material surface, and when the belt is driven, the protrusion end is Shear stress is applied in the film thickness direction. Therefore, there is a problem that cracks parallel to the circumferential direction of the belt are generated or cracks are generated in the protruding portion forming portion by repeating the belt driving for a long period or intermittently.

For this problem, a method of preventing cracking and cracking by joining a reinforcing member such as a tape to the end portion of the belt to improve the rigidity of the protruding portion forming portion and preventing deformation has been taken (for example, (See Patent Documents 1 to 3.)
However, measures such as attaching a reinforcing tape to the front or back of the belt incur extra costs, and the reinforcing tape peels off from the belt during use due to the shearing force acting between the belt and the reinforcing tape. As a result, cracks and cracks occur in the belt along the belt, which is not an essential improvement.
Further, since the reinforcing tape cannot be formed in an endless manner unlike the belt, the belt may be driven to peel off the joint portion at the end.
JP 2002-18873 A JP 2005-156581 A Japanese Patent Laid-Open No. 2004-177600

  An object of the present invention is to provide an endless belt that prevents peeling between the reinforcing layer and the base material and suppresses cracking of the reinforcing layer due to deformation, a method for manufacturing the endless belt, and the endless belt. An image forming apparatus is provided.

  Under such circumstances, as a result of intensive studies by the inventors, it has been found that the problems of the present invention can be solved by adopting the following means.

<1> A base material containing a filler and a resin, a protrusion provided at one end or both ends in the width direction of the base material on the inner peripheral surface side of the base material, and the base material A reinforcing layer provided on the outer peripheral surface side of the position facing the protrusion,
The reinforcing layer includes, as a main component, a resin composed of the same monomer as the monomer constituting the resin contained as a main component in the base material,
And the tensile yield strain in the circumferential direction of the reinforcing layer is larger than the tensile yield strain in the circumferential direction of the base material.

<2> The endless belt according to <1>, wherein the filler content of the base material is greater than the filler content of the reinforcing layer.

<3> The tensile yield strain in the circumferential direction of the reinforcing layer is 110% or more and 150% or less of the tensile yield strain in the circumferential direction of the base material. <1> or <2> It is an endless belt.

<4> Any one of <1> to <3>, wherein the number of folding times of the reinforcing layer according to the MIT test method is 105% to 200% of the number of folding times of the base material according to the MIT test method. The endless belt according to claim 1.

<5> The endless belt according to any one of <1> to <4>, wherein the reinforcing layer is endless in a circumferential direction of the endless belt.

<6> A resin film forming step of forming a resin film as a base material on the outer peripheral surface of the cylindrical mold,
A reinforcing layer forming step of forming a reinforcing layer at one end or both ends in the width direction of the resin film;
A protrusion forming step of forming a protrusion on a surface opposite to the surface on which the reinforcing layer is formed via the resin film;
The process for producing an endless belt according to any one of the above items <1> to <5>, wherein

<7> In the resin film forming step and the reinforcing layer forming step,
After applying a polyimide precursor solution or a polyamideimide solution containing a filler on the outer peripheral surface of a cylindrical mold to obtain a coating film, the coating film is dried to form a dry film for forming a substrate,
Then, after applying a polyimide precursor solution or a polyamideimide solution of the same type as the resin of the base material to the dry film surface to obtain a coating film, the coating film is dried to form a dry film for a reinforcing layer. Forming,
The method for producing an endless belt according to <6>, wherein the dry film for forming the base material and the dry film for forming the reinforcing layer are simultaneously imide-converted.

<8> The endless solvent according to <7>, wherein a residual solvent amount in the dry film for forming the substrate is 30% by mass or more and 60% by mass or less with respect to the total mass of the dry film. It is a manufacturing method of a belt.

<9> An image forming apparatus comprising the endless belt according to any one of <1> to <5>.

<10> Furthermore, it has a regulating member that regulates the movement of the protrusion provided on the endless belt,
<9> The image forming apparatus according to <9>, wherein the protrusion of the endless belt is regulated by regulating the protrusion by the regulating member.

<11> A charging device, an exposure device, a developing device, a transfer device, a transport device, and a fixing device, wherein the endless belt is attached to at least one of the transfer device, the transport device, and the fixing device. The image forming apparatus according to <9> or <10>, wherein the image forming apparatus is provided.

According to the inventions described in <1> to <5>, it is possible to provide an endless belt which prevents peeling between the reinforcing layer and the base material and suppresses the occurrence of cracking of the reinforcing layer due to deformation. it can.
According to the inventions described in <6> to 8>, there is provided a method for producing an endless belt that prevents peeling between the reinforcing layer and the base material and suppresses the occurrence of cracking of the reinforcing layer due to deformation. be able to.
According to the inventions described in <9> to <11>, the image forming apparatus includes an endless belt that prevents separation between the reinforcing layer and the base material and suppresses cracking of the reinforcing layer due to deformation. Can be provided.

  The endless belt of the present invention includes a base material containing a filler and a resin, protrusions provided at one end or both ends in the width direction of the base material on the inner peripheral surface side of the base material, and the base A reinforcing layer provided on the outer peripheral surface side of the position facing the protrusion through a material, and the reinforcing layer is the same monomer as the monomer constituting the resin contained as a main component in the base material And the tensile yield strain in the circumferential direction of the reinforcing layer is larger than the tensile yield strain in the circumferential direction of the base material.

The protrusion provided on the opposite surface side of the reinforcing layer through the base material is called a guide rib, and the rib is fitted into a groove formed near the end of the driving roll or near the roll end. To prevent the belt from meandering.
The conventional endless belt reinforces the belt by applying a reinforcing tape as the reinforcing layer. In the present invention, one end or both ends of the endless belt are made of the same resin as the outermost surface layer of the belt base material. Form and reinforce. As a result, the reinforcing layer and the belt base material become a single film, and the problem of peeling between the belt base material and the reinforcing layer as in the case of using the reinforcing tape is solved. Here, the “same resin” means that the monomers constituting the resin are the same.

  In this way, by forming a thickened film of the same resin as the belt base material at the belt width end, the rigidity at the belt end is improved, and the ribs run from the meandering regulating member. Can be prevented. Therefore, since it is possible to prevent a sudden bending stress from occurring at the end in the width direction of the endless belt, it is possible to prevent the reinforcing layer from being bent or cracked, and to maintain the reinforcing effect even after long-term use. it can.

On the other hand, as the rigidity of the belt end increases, the flexibility of the belt end decreases. Since the reinforcing layer is formed on the outer peripheral surface side of the endless belt, when the belt is stretched on the roll, the reinforcing layer may receive a bending stress larger than that of the base material on the roll, and the reinforcing layer may become a starting point of breakage.
Therefore, in the present invention, the tensile yield strain in the circumferential direction of the reinforcing layer is made larger than the tensile yield strain in the circumferential direction of the base material, so that even if the reinforcing layer receives bending stress larger than that of the base material, The generation of cracks in the layer can be prevented.

In order to make the tensile yield strain of the reinforcing layer larger than the tensile yield strain of the base material, the following methods or a combination thereof can be mentioned.
(1) The filler content of the reinforcing layer is made lower than the filler content of the substrate.
(2) The number average molecular weight of the resin contained as the main component in the reinforcing layer is made smaller than the number average molecular weight of the resin contained as the main component in the substrate.

Such an endless belt manufacturing method includes a resin film forming step of forming a resin film as a base material on the outer peripheral surface of a cylindrical mold, and a reinforcing layer at one end or both ends in the width direction of the resin film. And a protruding portion forming step of forming a protruding portion on a surface opposite to the surface on which the reinforcing layer is formed via the resin film.
In particular, when the base material and the reinforcing layer are formed with a polyimide resin or a polyamideimide resin as a main component, a resin film that becomes a base material and a resin film that becomes a reinforcing layer using a polyimide precursor solution or a polyamideimide precursor solution After forming the resin film, it is preferable to heat these resin films as one body and simultaneously convert them to imide. As a result, the bonding between the reinforcing layer and the belt base material becomes strong, and the problem of peeling of the reinforcing layer, which is observed when reinforcing with a conventional reinforcing tape, can be solved.
Furthermore, after the resin film for forming the base material is dried to form a dry film with a residual solvent amount within a certain range, a resin film for forming the reinforcing layer is formed, and the resin film for forming the base material is self-supporting. Therefore, the thickness of the reinforcing layer can be made constant.

  In the following, after describing the endless belt in more detail, the details of the manufacturing method of the endless belt will be described, and the image forming apparatus including the endless belt will be described.

1. Endless belt 1-1. Configuration of Endless Belt As shown in FIG. 1, the endless belt 10 of the present invention includes a base material 12, protrusions (sometimes referred to as “ribs”) 14, and a reinforcing layer 16.
The protrusion 14 is provided along the circumferential direction at one end or both ends in the width direction of the inner peripheral surface 12 a of the endless base material 12. As shown in FIGS. 2 and 3, when the endless belt of the present invention is stretched around the roll 18, as shown in FIG. 3, a concave groove provided along the circumferential direction at the end of the roll 18 in the width direction. Since the protrusions 14 are fitted into 18a (regulating member), when the endless belt 10 is driven by the roll 18, the position of the endless belt 10 can be prevented from moving in the width direction and meandering.

The reinforcing layer 16 is located at one end or both ends in the width direction of the endless base material 12 at a position facing the protrusion 14 via the base material 12 and on the outer peripheral surface side 12 b of the base material 12. It is provided along the circumferential direction of the material 12.
When the reinforcing layer 16 is provided, the rigidity in the circumferential direction of the endless belt 10 is improved by the reinforcing layer 16, and as described above, the protruding portion 14 can be prevented from coming off the concave groove 18a and riding on the surface of the roll 18. Therefore, since it is possible to prevent a sudden bending stress from occurring at the end in the width direction of the endless belt, it is possible to prevent the reinforcing layer from being bent or cracked, and to maintain the reinforcing effect even after long-term use. it can. In the case where the reinforcing layer 16 is formed on the inner peripheral surface side of the substrate 12, the reinforcing effect cannot be exhibited when the endless belt 10 comes off the concave groove 18 a and rides on the roll surface.

Moreover, since the outermost surface layer of the base material 12 and the reinforcement layer 16 are comprised with the same resin, the reinforcement layer 16 and the base material 12 are made into a single film, and the reinforcement layer 16 does not peel from the base material 12.
Further, since the tensile yield strain of the reinforcing layer 16 is larger than the tensile yield strain of the base material 12, the reinforcing layer 16 receives a larger bending stress than the base material 12 on the roll 18, or the protrusion 14 is concave. Even if a sudden bending stress occurs due to the separation from the groove 18a, the reinforcing layer 16 is unlikely to crack.

  The reinforcing layer 16 is also preferably endless in the circumferential direction of the substrate 12. When having an end in the circumferential direction, due to shear stress generated between the reinforcing layer 16 and the base material 12 or contact with the cleaning member, the end part is a separation starting point between the base material 12 and the reinforcing layer 16. There is a possibility.

  Here, the reinforcing layer 16 is provided in such a size as to face the protruding portion 14 with the base material 12 interposed therebetween and to cover the entire bonding position of the protruding portion 14 in the width direction of the base material 12. Any of the embodiments shown in FIGS. 4A to 4C may be used. 4A to 4C show an example of the aspect of the reinforcing layer 16 and do not limit the shape of the reinforcing layer. When the reinforcing layer 16 does not cover the entire bonding position of the protruding portion 14, as described above, when the protruding portion 14 moves out of the concave groove 18 a formed on the stretching roll and rides on the roll surface, the endless belt 10. An abrupt load is applied in the width direction, and the reinforcing layer 16 may be broken or cracked.

  However, when the endless belt 10 is applied to a transfer belt or the like of the image forming apparatus, it is necessary not to form the reinforcing layer 16 up to the image forming portion. When the reinforcing layer 16 is formed in the image forming portion, an image quality defect occurs due to a step difference due to the thickness of the reinforcing layer 16.

  The thickness of the reinforcing layer 16 is desirably 10 μm or more and not more than the thickness of the substrate 12. When the thickness is smaller than 10 μm, the strength is not sufficient and the reinforcing effect cannot be sufficiently provided. Moreover, when it becomes thicker than the base material 12, since the film thickness of a belt edge part will become thick too much, the flexibility of a belt edge part will fall and it may bend and crack in a stretch roll shape.

Although the thickness of the base material 12 can be appropriately determined according to the purpose of use, it is generally preferably about 20 μm or more and 200 μm or less, and particularly preferably 50 μm or more and 100 μm or less, from mechanical properties such as strength and flexibility. It is.
The base material 12 constituting the endless belt 10 is appropriately set in material, shape, size and the like according to the use, function, etc. of the endless belt.

  When the endless belt 10 of the present invention is used in an image forming apparatus described later, the base material 12 containing a conductive filler has a common logarithmic value of surface resistivity of 8 (logΩ / □) to 15 (logΩ / □). It is preferably within the range, and more preferably within the range of 10 (logΩ / □) to 13 (logΩ / □). When the common logarithmic value of the surface resistivity is in the range of 8 (log Ω / □) to 15 (log Ω / □), the toner scatters when used as an intermediate transfer belt or a transfer conveyance belt in an image forming apparatus. It is preferable that high image quality can be obtained without contamination and contamination due to charge-up can be prevented even without a static eliminator.

  The protrusion 14 may be provided only on one side edge (one end in the width direction) of the base 12, but from the viewpoint of further meandering prevention effect, durability, reinforcement effect, and the like, More preferably, it is provided on the side edge. The adhesion position (distance from the side edge) of the protrusion 14 to the base material 12 is appropriately set according to the use and function of the endless belt 10, the apparatus using the endless belt 10, and the like.

  The shape of the protrusion 14 can be determined as appropriate depending on the use conditions of the endless belt 10, but the cross section is preferably substantially rectangular in order to obtain a sufficient meandering prevention effect. The width of the protrusion 14 is usually preferably about 1 mm or more and 10 mm or less, particularly preferably 4 mm or more and 7 mm or less, from the viewpoint of the meandering prevention effect and durability. The thickness is not particularly limited, but is usually preferably about 0.5 mm or more and 5 mm or less, particularly preferably 1 to 2 mm, from the viewpoint of the meandering prevention effect and durability.

  The endless belt 10 of the present invention is suitably used for a photosensitive device, an intermediate transfer device, a transfer separation device, a conveying device, a charging device, a developing device, etc. in an electrophotographic copying machine, a laser printer or the like.

1-2. Composition of member constituting endless belt <base material>
(resin)
The material of the substrate 12 according to the present invention is appropriately set according to the use, function, etc. of the endless belt, and polyimide resin, epoxy resin, acrylic resin, silicone resin, polyester resin, polycarbonate resin, polyamide resin, polyamideimide resin It can be selected from thermoplastic resins such as, thermosetting resins and the like.
Among these resins, it is preferable that a polyimide resin or a polyamideimide resin is a main component. Since the polyimide resin and the polyamideimide resin are high tensile modulus materials, deformation due to stresses such as a support roll and a cleaning blade is small during driving, and image defects such as color misregistration are unlikely to occur.
In the present invention, the “main component” means containing 50% by mass or more based on the entire resin contained in the member (for example, the base material or the reinforcing layer). Furthermore, it is preferable to contain 50% by mass or more of a polyimide resin or a polyamideimide resin, and it is particularly preferable that the resin is only a polyimide resin or a polyamideimide resin. Other thermoplastic resins and thermosetting resins can be used in combination.

-Polyimide-
A polyimide resin (hereinafter sometimes referred to as “PI resin”) is obtained by imidizing a polyimide precursor by heating. The polyimide precursor is usually obtained as a polyamic acid solution by polymerizing a substantially equimolar tetracarboxylic dianhydride or derivative thereof and a diamine in a solvent.
The tetracarboxylic dianhydride is not particularly limited. Specifically, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4 , 4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5 , 6-Naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2'-bis (3,4-dicarboxyphenyl) sulfonic dianhydride, perylene- Examples include 3,4,9,10-tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, ethylenetetracarboxylic dianhydride, and the like.

On the other hand, specific examples of the diamine include 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, 3,3′-dichlorobenzidine, 4,4′-diaminodiphenyl sulfide. 3,3′-diaminodiphenylsulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 3,3′-dimethyl4,4′-biphenyldiamine, benzidine, 3,3′-dimethylbenzidine 3,3′-dimethoxybenzidine, 4,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenylpropane, 2,4-bis (β-aminotert-butyl) toluene, bis (p-β-amino- Tert-butylphenyl) ether, bis (p-β-methyl-δ-aminophenyl) benzene, bi -P- (1,1-dimethyl-5-amino-benzyl) benzene, 1-isopropyl-2,4-m-phenylenediamine, m-xylylenediamine, p-xylylenediamine, di (p-aminocyclohexyl) Methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylene, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2,11-diaminododecane, 1,2-bis-3-aminopropoxyethane, 2,2-dimethylpropylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 3-methylheptamethylenediamine, 5-methylnonamethylenediamine 2 , 17-diaminoeicosadecane, 1,4-diaminocyclohexane, 1,10-diamino-1,10-dimethyldecane, 12-diaminooctadecane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane , _{piperazine, H 2 N (CH 2)} 3 O (CH 2) 2 O (CH 2) NH 2, H 2 N (CH 2) 3 S (CH 2) 3 NH 2, H 2 N (CH 2) 3 _{N (CH 3) 2 (CH} 2) 3 NH 2 and the like.

  As the solvent for the polymerization reaction of the tetracarboxylic dianhydride and diamine, a polar solvent is preferably used from the viewpoint of solubility. As the polar solvent, N, N-dialkylamides are preferable. Specifically, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide, N , N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethylsulfoxide, hexamethylphosphortriamide, N-methyl-2-pyrrolidone, pyridine, tetramethylenesulfone, dimethyltetramethylenesulfone and the like. These can be used singly or in combination.

In the case of a substrate, the number average molecular weight of the PI resin is preferably 10,000 or more and 45,000 or less. If the number average molecular weight is less than 10,000, the film formability tends to deteriorate and the flex resistance tends to decrease. If it exceeds 45,000, the dispersibility of the carbon black powder, the formability as a tubular film, the thickness accuracy, etc. tend to be inferior.
The number average molecular weight of the PI resin is sampled at the time of resin synthesis, measured by a gel permeation chromatograph (GPC) using a standard polyethylene calibration curve, and the synthesis is continued until the target number average molecular weight is reached. Therefore, it is managed within the above range. Hereinafter, since the measurement method and adjustment method of the number average molecular weight of the resin are the same, description thereof is omitted.

-Polyamideimide-
For the production of a polyamideimide resin (hereinafter sometimes referred to as “PAI resin”), a trivalent carboxylic acid component having an acid anhydride group and an isocyanate or diamine can be generally used. In the present invention, as the trivalent carboxylic acid component, trimellitic anhydride is preferable in terms of flexibility, storage stability, and cost. Further, the trimellitic anhydride and a derivative of a trivalent carboxylic acid having an acid anhydride group that reacts with another isocyanate group or amino group can be used in combination. Preferred structures include the following.

Here, R represents hydrogen, an alkyl group having 1 to 10 carbon atoms, or a phenyl group, and X represents —CH ₂ —, —CO—, —SO ₂ —, or —O—.

The mixing ratio of the isocyanate or diamine and the tricarboxylic acid component is such that the total ratio of isocyanate groups or amino groups to the total number of carboxyl groups and acid anhydride groups of the acid component is 0.6 or more and 1.4 or less. It is preferable to set it to 0.7 or more and 1.3 or less, and it is particularly preferable to set it to 0.8 or more and 1.2 or less. If it is less than 0.6 or exceeds 1.4, it tends to be difficult to increase the molecular weight of the resin.
The PAI resin used in the present invention can be obtained, for example, by the following production method when isocyanate is used.

(1) A method in which an isocyanate component and a tricarboxylic acid component are used at a time and reacted to obtain a PAI resin.
(2) A method in which an excess amount of an isocyanate component is reacted with an acid component to synthesize an amide-imide oligomer having an isocyanate group at a terminal, and then a tricarboxylic acid component is added and reacted to obtain a PAI resin.
(3) After reacting an excess amount of a tricarboxylic acid component with an isocyanate component to synthesize an amide-imide oligomer having a carboxylic acid or an acid anhydride group at the terminal, the acid component and the isocyanate component are added and reacted to obtain a PAI resin. Method.

  In the case of using an amine, it can be obtained by the same production method as in the case of using the isocyanate shown above, but in addition, by reacting an amine with tribasic acid anhydride monochloride as an acid component at a low temperature for several hours. It can also be obtained. As the solvent to be used, those described for the PI resin can be used as well.

  The number average molecular weight of the PAI resin thus obtained is preferably 10,000 to 45,000 in the case of a substrate. If the number average molecular weight is less than 10,000, the film formability tends to deteriorate and the flex resistance tends to decrease. If it exceeds 45,000, the dispersibility of the carbon black powder, the formability as a tubular film, the thickness accuracy, etc. tend to be inferior.

(Filler)
The base material 12 of the endless belt of the present invention contains a filler in order to improve conductivity, impact resistance, heat resistance, friction resistance, electrical insulation, etc. according to the use, function, etc. of the endless belt. To do. In particular, when the endless belt 10 is applied to an image forming apparatus, the filler is preferably a conductive filler in order to control the resistance value of the endless belt 10.
As the conductive filler, for example, as an electron conductive conductive agent, a metal or alloy such as carbon black, carbon nanotube, graphite, aluminum, nickel, copper alloy, tin oxide, zinc oxide, titanium oxide (TiO), tin oxide − Indium oxide composite oxide and the like can be mentioned.
Examples of other electron conductive conductive agents include polyaniline, polypyrrole, polyacetylene, polythiophene, polyisothianaphthene, and polyethylenedioxythiophene as conductive polymers. Examples of the ion conductive conductive agent include Group 1 metal salts such as LiCl, LiCF ₂ SO ₄ , NaClO ₄ , LiBF ₄ , NaCl, and various surfactants such as cationic, anionic, and nonionic surfactants.
Two or more kinds of these conductive agents may be mixed.

  Among these conductive fillers, carbon black is preferable from the viewpoint of low hygroscopicity and good dimensional stability of the formed substrate, mechanical stability over time, and electrical stability. .

As for the said electrically conductive filler, it is especially preferable that the surface is oxidized and adjusted to pH 5.0 or less. When the pH is 5.0 or less, the dispersibility in the binder resin is improved by the effect of the oxygen-containing functional group attached to the surface, and the resistance variation of the intermediate transfer member can be reduced.
In the endless belt of the present invention, from the viewpoint of resistance variation control, it is preferable to use acidic carbon black that has been subjected to an oxidation treatment as a conductive filler and has a carboxyl group, a quinone group, a lactone group, a hydroxyl group, or the like on the surface.

  The amount of filler added is not particularly limited. For example, when the filler is carbon black, the amount of the filler is preferably 5 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the base resin. In such a case, the range is preferably 1 part by mass or more and 50 parts by mass or less. Within the above range, the resistance value can be easily controlled.

  The filler may be directly dispersed in a polyimide precursor solution described later, or a method in which the filler is previously dispersed in a solvent at the time of polymerization of the polyimide precursor may be used. Further, the dispersion method is not particularly limited, and for example, there is a method of dispersing with a ball mill or ultrasonic waves.

  The substrate 12 may have a single layer structure made of a single composition or a multilayer structure made of two or more layers in which different compositions are laminated. In the case of a single layer structure, it is composed of a layer containing the above resin and filler. In the case of a multilayer structure, in addition to the layer containing the above-described resin, other layers can be set according to the use, function, etc. of the endless belt. However, in the case of a multilayer structure, the outermost surface layer contains the resin.

<Reinforcing layer>
(resin)
The resin of the reinforcing layer 16 is mainly composed of a monomer that constitutes the resin contained in the substrate 12 as a main component and a resin that is composed of the same monomer. With such a configuration, the boundary between the reinforcing layer 16 and the base material 12 disappears to form a single film, and the phenomenon of peeling between the base material 12 and the reinforcing layer 16 is eliminated. Bonding between the reinforcing layer 16 and the substrate 12 is also strong.
Therefore, the resin described in the base material 12 is applied as the resin of the reinforcing layer 16. However, the resin of the reinforcing layer 16 may have a composition different from that of the resin of the substrate 12 or a polymerization method. The types of monomers suitable as the resin for the reinforcing layer 16 and the method for producing the resin are also the same as those for the substrate 12.
If the resin of the reinforcing layer 16 is mainly composed of a monomer constituting the resin contained in the base material 12 as a main component and a resin composed of the same monomer, other thermoplastic resins, thermosetting resins, etc. Can be used together.

The number average molecular weight of the resin of the reinforcing layer 16 is preferably smaller than the number average molecular weight of the resin of the base material 12 from the viewpoint of making the tensile yield strain of the reinforcing layer 16 larger than the tensile yield strain of the base material 12.
In order to realize this, there can be mentioned a method of increasing the heating temperature or extending the heating time when polymerizing the resin of the base material 12 than when polymerizing the resin of the reinforcing layer 16.

When PI resin is applied to the reinforcing layer 16, the number average molecular weight of the PI resin is preferably 10,000 or more and 45,000 or less. If the number average molecular weight is less than 10,000, the film formability tends to deteriorate and the flex resistance tends to decrease. If it exceeds 45,000, the dispersibility of the carbon black powder, the formability as a tubular film, the thickness accuracy, etc. tend to be inferior.
When a PAI resin is applied to the reinforcing layer 16, the number average molecular weight of the PAI resin is preferably 10000 or more and 45000 or less. If the number average molecular weight is less than 10,000, the film formability tends to deteriorate and the flex resistance tends to decrease. If it exceeds 45,000, the dispersibility of the carbon black powder, the formability as a tubular film, the thickness accuracy, etc. tend to be inferior.

(Filler)
In order to make the tensile yield strain of the reinforcing layer 16 larger than the tensile yield strain of the base material 12, (1) it is preferable that the filler content of the reinforcing layer 16 is smaller than the filler content of the base material 12. is there.

  Therefore, in the present invention, the filler content of the reinforcing layer 16 is less than the filler content of the substrate 12. When the mass content of the filler in the substrate 12 relative to the resin in the substrate 12 is 100%, the mass content of the filler in the reinforcement layer 16 relative to the resin in the reinforcement layer 16 is 0% by mass or more and 50% by mass. % Or less, and more preferably 5% by mass or more and 30% by mass or less. If it is within the above range, a range of suitable mechanical property values described later can be satisfied.

The filler is used by being dispersed and mixed in the resin. The filler may be modified by chemical treatment on the surface of the filler in order to improve the dispersibility of the filler in the resin.
As the chemical treatment of the filler surface, a general method is used, and examples include treatment with a silane coupling agent and treatment with a treatment agent composed of an organic carboxylic acid or an organic carboxylate. Examples of the treatment method include a liquid phase treatment in which the filler particles are dispersed in water or an organic solvent and a surface treatment agent is allowed to act, or a gas phase treatment in which a vaporized surface treatment agent is caused to act on the filler particles.
As the silane coupling agent, generally used compounds are used, and specifically, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, etc. Is mentioned.

<Protrusions>
The protrusion 14 in the endless belt 10 of the present invention is provided at the end of the endless belt 10 in the width direction for the purpose of preventing meandering when the belt is stretched around the roll 18 and traveled in the circumferential direction. Mounted on both sides or one side. As long as the protrusion 14 in the present invention is a generally known meandering prevention protrusion, the material, shape, characteristic value, attachment method, and the like are not limited.
Specific examples of the material of the protrusion 14 include rubber materials such as silicon rubber, fluorine rubber, urethane rubber, EPDM, NBR, CR, chlorine-based polyisoprene, hydrogenated poly-protrusion tadiene, and butyl rubber. May be used alone or in a blend of two or more.

1-3. Relationship between mechanical properties of base material and reinforcing layer <Tensile yield strain>
In the endless belt 10 of the present invention, the tensile yield strain of the reinforcing layer 16 is larger than the tensile yield strain of the substrate 12. If the tensile yield strain in the circumferential direction of the reinforcing layer 16 is larger than the tensile yield strain in the circumferential direction of the substrate 12, cracks and cracks are less likely to occur with respect to the load in the belt width direction, and the protrusion for running guide Even if the unit 14 is attached and the electrophotographic image forming apparatus described later is run for a long time, it has excellent durability and can be used stably.
If the tensile yield strain in the circumferential direction of the reinforcing layer 16 is too larger than the tensile yield strain in the circumferential direction of the base material 12, the difference in tensile yield strain between the reinforcing layer 16 and the base material 12 is large. As a result, shear stress is generated and cracks may occur. In order to exhibit the above effect more effectively, the tensile yield strain in the circumferential direction of the reinforcing layer 16 is preferably 101% or more and 200% or less of the tensile yield strain in the circumferential direction of the substrate 12. % To 150% is more preferable.

  In the present invention, an average value measured five times according to JIS K7161 (1994 version, the same applies hereinafter) is taken as a measured value of tensile yield strain. More specifically, it is punched with dumbbell No. 3 to prepare a test piece (width 5 mm), and measured 5 times at a tensile speed of 20 mm / min using MODEL-1605N manufactured by Aiko Engineering Co., Ltd. To do. The measurement conditions at this time are an environment having a temperature of 22.5 ± 0.5 ° C. and a relative humidity of 55 ± 2% RH.

<Flexibility>
When the endless belt 10 is stretched around the roll 18, a bending load acts on the endless belt 10 on the roll 18. Therefore, the endless belt 10 needs to be flexible to withstand a bending load that repeatedly acts.
In the endless belt 10 of the present invention, the folding endurance of the reinforcing layer 16 in the MIT test is preferably 105% or more, more preferably 120% or more of the folding endurance of the base material 12 in the MIT test. When the folding endurance in the MIT test of the reinforcing layer 16 is 105% or more of the endurance folding in the MIT test of the base material 12 belt, it is difficult to generate a crack when bent by a roll. Even if the electrophotographic image forming apparatus described later is run for a long period of time, it has excellent durability and can be used stably.

The bending resistance in the present invention is evaluated by the number of foldings by the MIT test method. Folding resistance measurement by the MIT test method conforms to the measurement method described in JIS P8115 (1994). However, “paper and paperboard” in JISP8115 (1994) is replaced with “polyimide film” and measured using an MIT testing machine shown in FIG.
FIG. 5 is a schematic configuration diagram for explaining the MIT testing machine. The MIT testing machine shown in FIG. 5 has a bending device 6 attached to the bending device attachment surface 4 and having a radius of curvature of 0.38 mm for bending the test piece 2 and a load attached to the plunger 8. And a grip 9 for hanging.

The procedure for measuring the folding endurance by the MIT test method is as follows.
One of the test pieces 2 is sandwiched by a bending device 6. Further, the other one of the test pieces 2 is sandwiched by the gripping tool 9, and a load of 9.8 N (1 kgf) is applied to the test piece. Next, the bending device 6 is rotated at an angle of 135 ± 2 ° at a speed of 175 ± 10 times per minute, and the test piece 2 to which a load is applied is repeatedly bent at the curvature surface of the bending device 6 and stress is applied. To break.

The folding strength FE is obtained according to the following formula (1) from the number of times of folding N until breakage.
Formula (1): FE = log ₁₀ N

Further, the folding endurance number FN is obtained according to the following formula (2).
Formula (2): FN = 10 ^FE

2. Endless Belt Manufacturing Method The endless belt manufacturing method of the present invention includes a resin film forming step of forming a resin film for forming the substrate 12 on the outer peripheral surface of a cylindrical mold, and a width direction of the resin film. A reinforcing layer forming step for forming the reinforcing layer 16 at one end or both ends, and a protruding portion forming step for forming the protruding portion 14 on the surface opposite to the surface on which the reinforcing layer 16 is formed via the resin film. And having.

  As described above, since the base material 12 and the reinforcing layer 16 of the endless belt 10 of the present invention preferably include a polyimide or polyamideimide resin as a main component as a resin, a polyimide precursor solution or a polyamideimide precursor solution is used. It is preferable to form a base material or a reinforcing layer. In this case, after forming a coating film for forming a base material and drying the coating film to obtain a dry film for forming the base material, a coating film for forming a reinforcing layer is formed on the dry film, It is preferable to dry the coating film to form a dry film for forming the reinforcing layer, and then heat the dry film as a unit to simultaneously convert the imide.

  Hereinafter, the manufacturing method of the endless belt 10 when a polyimide resin or a polyamideimide resin is used as the resin of the base material 12 and the reinforcing layer 16 will be described for each step.

2-1. Resin film formation process In the resin film formation process, the resin film used as a substrate is formed.
First, a polyimide precursor in which a polyimide precursor (hereinafter sometimes referred to as “PI precursor”) or a polyimide amide precursor (hereinafter sometimes referred to as “PAI precursor”) is dissolved in an aprotic polar solvent. A solution (hereinafter may be referred to as “PI precursor solution”) or a polyamideimide precursor solution (hereinafter also referred to as “PAI precursor solution”) is prepared.

  As the PI precursor and the PAI precursor, those composed of various combinations listed above can be used. In addition, the PI precursor and the PAI precursor may be used as a mixture of two or more, or may be used as a copolymer obtained by mixing an acid or amine monomer.

  The PI precursor or PAI precursor is prepared as a PI precursor solution or PAI precursor solution by dissolving in the above-mentioned solvent. In addition, the selection of the mixing ratio, concentration, viscosity and the like of the PI precursor or PAI precursor in this preparation is performed by appropriately adjusting.

Next, a PI precursor solution or a PAI precursor solution (hereinafter sometimes referred to as “precursor solution”) is applied to the outer peripheral surface of the cylindrical mold.
As the cylindrical mold, aluminum or stainless steel is preferably used. In particular, it is preferable to use stainless steel from the viewpoint of workability and surface hardness. However, a material having a thermal expansion coefficient smaller than that of the resin film in relation to the PI resin film or PAI resin film (hereinafter sometimes referred to as “resin film”) to be produced is used as the cylindrical mold material. This is not preferable because it makes it difficult to remove the resin film.

  In the case where the cylindrical mold is aluminum, when heated to 350 ° C., the strength is lowered and deformation is likely to occur. Such thermal deformation of aluminum is likely to occur when strain is accumulated during cold working into a cylindrical mold shape. In order to remove such distortion, there is a method of annealing (annealing) aluminum. However, since thermal deformation also occurs by annealing, it is necessary to perform processing to a predetermined shape thereafter. Annealing includes a method in which an aluminum material is heated to a range of 350 ° C. or higher and 400 ° C. or lower and naturally cooled in air.

  Moreover, since there exists a possibility that a resin film may adhere | attach on the cylindrical mold surface, it is preferable that the mold release property is provided to the surface of the cylindrical mold. In particular, in the present invention, since the coating is peeled off by injecting pressurized air into the gap between the cylindrical mold and the resin coating, it is preferable that the above-mentioned release property is imparted.

  In order to provide releasability, the surface of the mold is released so that the surface of the cylindrical mold is plated with chromium or nickel, or the surface is covered with a fluorine resin or silicone resin, or the polyimide resin is not adhered to the surface. It is effective to apply an agent.

  If the residual solvent cannot be completely removed from the resin film of the base material when the precursor film described below is dried, or if the water generated during heating cannot be completely removed, the resin film will be partially lantern-shaped. Swelling may occur. This is a particularly serious problem when the thickness of the resin film exceeds 50 μm. In that case, it is effective to roughen the surface of the cylindrical mold to an arithmetic average roughness Ra of about 0.2 μm to 2 μm. As a result, the residual solvent or water vapor can be discharged to the outside through a slight gap formed between the cylindrical mold and the resin film, and swelling can be prevented. For roughening the surface of the cylindrical mold, a method such as blasting, cutting, sandpapering or the like is used.

  The method of applying the precursor solution to the surface of the cylindrical mold is not limited as long as the polyimide precursor solution or the polyamideimide precursor solution is applied in a direction parallel to the axis of the cylindrical mold. Specifically, a method of applying the precursor solution to the outer peripheral surface of the cylindrical mold by discharging the precursor solution from the nozzle in the direction of the axis of rotation of the cylindrical mold, or a precursor of the cylindrical mold. In addition to the immersion annular coating method in which the body solution is immersed and pulled up, there are a protruding annular coating method, a method in which the precursor solution is poured into the inner peripheral surface of the cylindrical mold in the axial direction, and the like.

FIG. 6 shows an outline of a coating apparatus that applies the precursor solution to the outer peripheral surface of the cylindrical mold by moving the precursor solution in the direction of the rotation axis of the rotating cylindrical mold while discharging the precursor solution from the nozzle.
Here, although not shown, the cylindrical mold 29 is disposed on a pedestal having an arm that is supported to be horizontally rotatable (arrow A) via a holding member. Although not shown, the cylindrical mold 29 is connected to a driving means (rotating means) for rotating the cylindrical mold 29 through a holding member.
In addition, as a flow-down device 14 that flows the precursor solution 26 down and attaches the precursor solution 26 to the cylindrical mold 29 around the cylindrical mold 29, the precursor solution 26 is supplied to the nozzle 23 and the nozzle 23. A container 22 and a pressurizing device 24 for flowing the precursor solution 26 from the nozzle 23 through the container 22 are provided. As the container 22, for example, a device using a meniscus cylinder, a screw, or the like is applied.
In FIG. 6, the nozzle 23 and the container 22 are integrally formed. However, the nozzle 23 and the container 22 are connected by a connecting pipe, and the nozzle 23 and the container 22 are separated and placed separately. It may be a form. In this case, the flow amount may be controlled by interposing a solenoid valve, for example, between the nozzle 23 and the container 22.

  Usually, the precursor solution 26 has a high viscosity of, for example, 1 MPa · s or more and does not flow down naturally. Since the film thickness of the coating film is determined by the discharge amount of the solution, the discharge amount must be constant during application. The solution may be discharged from the container 22 with pressurized air, but in order to ensure quantification, the solution may be supplied by a pump. The pump is preferably a MONO pump that can discharge a constant amount without interruption.

  The distance between the nozzle 23 and the cylindrical mold 29 may be arbitrary, but is preferably about 10 mm or more and 100 mm or less so that the falling liquid is not interrupted. If the liquid breaks off, bubbles may be involved.

  Around the cylindrical mold 29, a blade 25 is arranged as a smoothing means for smoothing the precursor solution 26 attached to the cylindrical mold 29. The blade 25 is abutted against and pressed against the cylindrical mold 29 to smooth the precursor solution 26 attached to the cylindrical mold 29. The tip of the blade 25 is curved (so as to be bent) and is pressed against the cylindrical mold 29.

  Here, as the pressure contact force of the blade 25 to the cylindrical mold 29, for example, according to the maximum deflection width (for example, 0 mm or more and 2 mm or less) during rotation of the cylindrical mold 29 having a roundness of 0 mm or more and 1 mm or less, 25 is in the range of 0.2N or more and 4N or less so that the fluctuation width can follow the fluctuation width, and the spiral coating is not generated on the coating film.

  As the nozzle 23 and the blade 25 adhere and smooth the precursor solution 26 on the cylindrical mold 29, the attached portion and the smoothed portion are relatively positioned at one end of the cylindrical die 29 every time the core body rotates. To the other end in the horizontal direction (arrow B). Although not shown, this configuration may be a configuration in which the nozzle 23 and the blade 25 are moved, or a configuration in which the cylindrical mold 29 is moved, and can be configured by a known technique.

  The application conditions are such that the rotational speed of the cylindrical mold 29 is 20 rpm or more and 200 rpm or less, and the coating speed V is 0.1 m / min or more and 2.0 m / min or less. Is preferred.

In this embodiment, first, the precursor solution 26 is attached to the cylindrical mold 29 by causing the precursor solution 26 to flow down from the nozzle 23 while rotating the cylindrical mold 29 in the direction of arrow A. Immediately after this, the blade 25 is abutted against the cylindrical mold 29 to smooth the precursor solution 26 adhering to the cylindrical mold 29. Then, each time the cylindrical mold 29 rotates, the attachment point (position of the nozzle 23) and the smoothing point (position of the blade 25) are moved horizontally from one end of the cylindrical mold 29 to the other end (arrow B). ).
Thus, the precursor solution 26 is apply | coated to the cylindrical metal mold | die 29 outer peripheral surface, a coating film is formed, and application | coating is complete | finished.

  The blade 25 is made of a plate having a thickness of about 0.1 mm to 1 mm made of a metal such as stainless steel or brass, or a resilient material such as fluororesin or polyethylene. The width needs to be wider than at least the pitch (horizontal movement speed / rotational speed), but even if it is too wide, streaks may remain. While the blade 25 is pressed against the precursor solution 26 and smoothed, the resin solution is present between the cylindrical mold 29 and the blade 25, so that they are not in direct contact with each other.

  Since the film thickness of the coating film P is determined by the discharge amount of the precursor solution 26, the discharge amount is adjusted by a liquid feed pump.

The precursor coating film for forming a substrate thus obtained is heated and dried, and the solvent is evaporated at a high temperature to form a dried film. The resin film obtained by making a dry film has self-supporting property. The amount of residual solvent in the dry film at this time is preferably 30% by mass or more and 60% by mass or less with respect to the total mass of the dry film. If the amount of residual solvent exceeds 60% by mass, sufficient self-supporting property of the substrate 12 cannot be obtained, and it may be difficult to stabilize the thickness of the reinforcing layer applied to the surface. Moreover, when the residual solvent amount is less than 30% by mass, the adhesion between the base material 12 and the reinforcing layer 16 may be insufficient.
Specifically, it is preferable to remove the residual solvent by heating and drying the precursor coating film at a temperature in the range of 150 ° C. to 200 ° C. for 30 minutes to 60 minutes.

  When the obtained dried film is further heated to be converted into an imide, and then a precursor solution for forming a reinforcing layer, which will be described later, is applied, the adhesion between the reinforcing layer 16 and the substrate 12 is significantly reduced. In the step of applying the precursor solution, it is preferable to keep the dry film for forming the base material 12 without imide conversion. The solvent in the dry film for forming the base material 12 and the precursor solution for forming the reinforcing layer are mixed to make the adhesion between the base material 12 and the reinforcing layer 16 after imide conversion very strong. it can.

2-2. Reinforcing layer forming step The reinforcing layer 16 forms a dry film for forming the base material 12 and then forms a precursor solution containing the same resin as the main component resin of the base material 12 as a main component. It is applied to a desired position on the dried film, followed by drying and imide conversion. Here, the same resin means that the constituent monomers are the same chemical species, and those having different compositions and different polymerization forms are also in the same range. By forming the reinforcing layer 16 with the same polyimide resin or polyamide-imide resin as the base material 12, there is no boundary between the reinforcing layer 16 and the base material 12, and the bondability can be further strengthened.

  The coating method is a flow coating method as shown in FIG. 6 in which the coating liquid is applied directly from the nozzle while rotating the mold on which the belt is installed, and the coating liquid is spirally applied while being flattened by the blade. An ink jet method in which fine droplets are applied while being discharged can be applied.

  When applying the precursor coating solution for forming the reinforcing layer by applying the flow coating method, the method described in the method for applying the precursor coating solution for forming the base material can be similarly applied.

2-3. Imide Conversion In the method for producing an endless belt of the present invention, as described above, in the step of applying the precursor layer forming solution, the resin film for forming the base material is not converted to imide, and a part of the solvent evaporates. Preferably, the precursor solution for reinforcing layer formation is applied, and after obtaining the step of evaporating a part of the solvent of the precursor coating film for reinforcing layer formation, It is preferable to simultaneously convert the resin film and the resin film for forming the reinforcing layer to imide.

  The imide conversion reaction varies depending on the type of monomer to be applied, but preferably proceeds in the range of 300 ° C. to 450 ° C., more preferably around 350 ° C., by heating the precursor coating for 20 minutes to 60 minutes. As a result, a PI resin film or a PAI resin film can be formed. If the imide conversion reaction is insufficient, the mechanical properties and the electrical properties are inferior. Therefore, the temperature and time at which the imide conversion reaction proceeds sufficiently must be set.

If the solvent remains during imide conversion by heating reaction, the resin film may swell, so it is preferable to completely remove the residual solvent before reaching the final heating temperature It is preferable that the resin film is formed by heating at a constant or constant speed and heating.
At this time, the imide conversion reaction can be performed after removing the polyamic acid film from the mold and replacing it with another mold, or using the same cylindrical mold as it is.
The formed PI resin film or PAI resin film is removed from the cylindrical mold or the replaced mold and cut to an appropriate width, whereby the substrate 12 provided with the reinforcing layer 16 can be obtained.

2-4. Protrusion part formation process Protrusion part 14 can be obtained by preparing materials, such as an elastic member, and hardening and forming by a publicly known method.
As an example, the production method will be described by taking the case of using polyurethane as an elastic member as an example. First, an isocyanate component and a polyol component, which are raw materials for polyurethane, are prepared, then an isocyanate component is added, and this is heated and cured to urethane. It is obtained by preparing a sheet and forming it into a desired shape using a big mold or the like. It can also be pressed into a desired shape by a press machine and formed into a desired shape.

  There is no restriction | limiting also in the attachment method to the base material 12 of the projection part 14, The attachment method by the generally well-known adhesive agent excellent in adhesive strength and durability can be used. Specific examples of the adhesive include Silex 100 mainly composed of a specially modified silicon polymer manufactured by Konishi Co., Ltd., and Super X No. 1 mainly composed of a specially modified silyl-containing epoxy resin of Cemedine Co., Ltd. Adhesion by 8008 can be given.

  In addition, in the manufacturing method of the endless belt of the present invention, other steps can be appropriately performed, and the present invention is not limited to the above steps.

3. Image Forming Apparatus The endless belt of the present invention can be applied to a photosensitive device, an intermediate transfer device, a transfer separation device, a transport device, a charging device, a developing device, etc. in an electrophotographic copying machine, a laser printer or the like.
The image forming apparatus of the present invention is not particularly limited as long as it includes the endless belt of the present invention, and includes an endless belt 10 and a regulating member that regulates the movement of the protrusion 14 of the endless belt 10. If it has, since a projection part can be controlled by a control member, meandering of an endless belt can be controlled.

The image forming apparatus of the present invention includes a charging device, an exposure device, a developing device, a transfer device, a transport device, and a fixing device, and at least one of the transfer device, the transport device, and the fixing device. For example, a toner provided on an image carrier such as a normal monocolor image forming apparatus containing only a single color toner in a developing device or a photosensitive drum can be used. Examples thereof include a color image forming apparatus in which primary transfer is sequentially performed on an intermediate transfer body, and a tandem color image forming apparatus in which a plurality of image holding bodies each having a developing device for each color are arranged in series on the intermediate transfer body.
In the image forming apparatus of the present invention, specifically, the endless belt 10 can be applied to a transfer belt, an intermediate transfer belt, a transfer conveyance belt, a fixing belt, a paper conveyance belt, and the like.

Next, an example of the image forming apparatus of the present invention will be shown.
FIG. 7 is a schematic diagram for explaining a main part of a tandem type image forming apparatus using the intermediate transfer belt 46. Specifically, in FIG. 7, a charging roll 43 (charging device) that uniformly charges the surface of the photoconductor 39, a laser generator 38 (exposure device) that exposes the surface of the photoconductor 39 to form an electrostatic latent image, and a photoconductor The latent image formed on the surface 39 is developed using a developer, and a developer 45 (developing device) that forms a toner image, a transfer roll 40 that transfers the developed toner image to the intermediate transfer belt 46, and a photoconductor A photoconductor cleaner 44 (cleaning device) that removes adhered toner, dust, and the like, a fixing roll 32 that fixes a toner image on a transfer material, and the like can be optionally provided by a known method as necessary. By providing the endless belt of the present invention as the intermediate transfer belt 46, high-quality transfer image quality can be stably obtained even in the tandem image forming apparatus having the above-described configuration.

  Further, the configuration of the image forming apparatus shown in FIG. 7 will be described in detail. The image forming apparatus shown in FIG. 7 includes four toner cartridges 31, a pair of fixing rolls 32, a backup roll 33, a tension applying roll 34, a secondary transfer roll 35, a paper path 36, a paper tray 37, a laser generator 38, It includes four photoconductors 39, four primary transfer rolls 40, a drive roll 41, a transfer cleaner 42, four charging rolls 43, a photoconductor cleaner 44, a developing device 45, an intermediate transfer belt 46, and the like as main components. It becomes.

  First, around the photoconductor 39, a primary transfer roll 40 and a photoconductor cleaner 44 arranged via a charging roll 43, a developing device 45, and an intermediate transfer belt 46 are arranged counterclockwise. The member forms a developing unit corresponding to one color. Each developing unit is provided with a toner cartridge 31 for replenishing the developer in the developing unit 45. The photosensitive member 39 of each developing unit is exposed to a photosensitive member between the charging roll 43 and the developing unit 45. A laser generator 38 capable of irradiating the surface of the body 39 with laser light corresponding to image information is provided.

  Four developing units corresponding to four colors (for example, cyan, magenta, yellow, and black) are arranged in series in a substantially horizontal direction in the image forming apparatus. An intermediate transfer belt 46 is provided so as to pass through a contact portion with the transfer roll 40. The intermediate transfer belt 46 is stretched by a backup roll 33, a tension applying roll 34, and a driving roll 41 provided in the counterclockwise direction in the following order on the inner peripheral side thereof. The four primary transfer rolls are located between the backup roll 33 and the tension applying roll 34. A transfer cleaner 42 for cleaning the outer peripheral surface of the intermediate transfer belt 46 is provided on the opposite side of the drive roll 41 with the intermediate transfer belt 46 in contact with the drive roll 41.

  Further, on the opposite side of the backup roll 33 via the intermediate transfer belt 46, the toner formed on the outer peripheral surface of the intermediate transfer belt 46 on the surface of the recording paper conveyed from the paper placing member 37 via the paper path 36. A secondary transfer roll 35 for transferring an image is provided so as to be in pressure contact with the backup roll 33.

  In addition, a paper holder 37 that stocks recording paper is provided at the bottom of the image forming apparatus, and a backup roll 33 and a secondary transfer roll 35 that form a secondary transfer unit from the paper holder 37 via a paper path 36. It can supply so that it may pass through the press-contact part. The recording sheet that has passed through the pressure contact portion can be further transported by a transport means (not shown) so as to pass through the pressure contact portions of the pair of fixing rolls 32, and can finally be discharged out of the image forming apparatus.

  Next, an image forming method using the image forming apparatus of FIG. 7 will be described. The toner image is formed for each developing unit, and the surface of the photoconductor 39 rotating counterclockwise by the charging roll 43 is uniformly charged, and then the photoconductor 39 charged by the laser generator 38 (exposure device). A latent image is formed on the surface, and then the latent image is developed with a developer supplied from the developing unit 45 to form a toner image, which is conveyed to a pressure contact portion between the primary transfer roll 40 and the photoconductor 39. The transferred toner image is transferred to the outer peripheral surface of the intermediate transfer belt 46 rotating in the arrow A direction. The photosensitive member 39 after the toner image is transferred is cleaned with toner or dust attached to the surface thereof by the photosensitive member cleaner 44 to prepare for the formation of the next toner image.

  The toner images developed for each color development unit are sequentially superimposed on the outer peripheral surface of the intermediate transfer member 86 so as to correspond to the image information, and are conveyed to the secondary transfer unit by the secondary transfer roll 35. The image is transferred from the sheet placing member 37 to the surface of the recording sheet conveyed via the sheet path 36. The recording paper on which the toner image has been transferred is further fixed by being heated by pressure when passing through the pressure contact portion of a pair of fixing rolls 32 constituting the fixing portion, and after the image is formed on the surface of the recording medium. Then, it is discharged out of the image forming apparatus.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

[Example 1]
<Production of endless belt>
(Preparation of base material)
500% strength solution of a polyimide precursor prepared by synthesizing 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether in N-methyl-2-pyrrolidone 500 20 parts by mass of carbon black (SPECIAL BLACK 4 (manufactured by Degussa)) was added and dispersed in a sand mill for 6 hours at room temperature, and the viscosity of the carbon black-dispersed polyimide precursor solution was as follows: It was 45 Pa · s at room temperature (22 ° C.).

  On the other hand, an aluminum cylindrical mold having an outer diameter of 200 mm, a length of 400 mm, and a surface roughened by blasting to Ra 0.8 μm is prepared, and a silicone mold release agent (trade name: KS700, Shin-Etsu Chemical Co., Ltd.) is provided on the outer surface. Made) and baked at 300 ° C. for 1 hour.

Further, as a spin coating process, as shown in FIG. 6, the axial direction of the cylindrical mold 29 was horizontal and rotated at 40 rpm in the direction of arrow A. The blade 25 is made of polyethylene having a width of 220 mm and a thickness of 1 mm, and has elasticity. This was pressed against a cylindrical mold 29, and the polyimide precursor solution 26 was extruded from the container 22 through a nozzle 23 having a diameter of 3 mm at an air pressure of 0.8 MPa and a flow rate of 12 ml / min. When the polyimide precursor solution passed through the blade 25, the blade 25 was spread and a gap was formed between the blade 25 and the cylindrical mold 29.
Next, the nozzle 23 and the blade 25 were moved in the direction of arrow B at a speed of 60 mm / min. Under this condition, the nozzle 23 and the blade 25 move by 1.5 mm per rotation of the cylindrical mold 21. In addition, at the time of application | coating, the uncoated part of 5 mm was provided in the both ends of the cylindrical metal mold | die 29. FIG.

  Next, the cylindrical mold 29 coated with the polyimide precursor solution 26 was heated and dried at 120 ° C. for 35 minutes while being rotated at 6 rpm while being kept horizontal. After drying, a part of the obtained polyimide precursor film was cut out and the amount of residual solvent in the film was measured with a thermogravimetric measuring device DTG-50 manufactured by Shimadzu Corporation.

(Production of reinforcement layer)
Thereafter, carbon obtained by adding 10 parts by mass of the above-mentioned carbon black to 500 parts by mass of the above-described polyimide precursor 20% by weight concentration solution at both ends 33 mm of the film obtained by drying and dispersing in a sand mill for 6 hours. A black dispersion polyimide precursor solution was spin-coated. The coating conditions for the 20% by weight polyimide precursor solution were the same as the conditions for applying the carbon black-dispersed polyimide precursor solution described above. Then, the cylindrical mold 29 is kept horizontal and rotated at 6 rpm while being heated and dried at 120 ° C. for 35 minutes, and then heated at 360 ° C. for 30 minutes to form a polyimide resin film having a thickened end. did. The width of the polyimide resin film removed from the cylindrical mold 29 was adjusted to 350 mm.

(Production of protrusions)
Next, as an adhesive, a urethane resin (Tigers Polymer Co., Ltd. typelen TR100-70 (trade name)) of JIS K6253 (1997) type A durometer hardness A70 / S having a width of 5 mm and a height of 15 mm is used. Super X No. manufactured by Cemedine, a liquid room temperature curing adhesive A piece coated with 8008 so as not to protrude from the adhesive surface was affixed to the inner peripheral surface of both end portions in the width direction of the polyimide resin film to form protrusions, whereby an endless belt was obtained.

<Durability test>
The obtained endless belt was used as an intermediate transfer belt of the tandem type image forming apparatus shown in FIG.
As a result, it was not broken in a durability test of 3 × 10 ⁶ rotations.

<Preparation of mechanical property evaluation sample>
An evaluation sample of mechanical properties was produced by the following method.

(Preparation of evaluation sample of base material)
A 500 mass% solution of a polyimide precursor prepared by synthesizing 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether in N-methyl-2-pyrrolidone 500 20 parts by mass of carbon black (SPECIAL BLACK 4 (manufactured by Degussa)) was added and dispersed in a sand mill at room temperature for 6 hours, and as a spin coating process, as shown in FIG. The axial direction of the cylindrical mold 29 was horizontal and rotated at 40 rpm, a blade having a width of 220 mm and a thickness of 1 mm was pressed against the cylindrical mold, and the polyimide precursor solution 26 was passed through the nozzle 23 having a diameter of 3 mm from the container 22 to the air. The polyimide precursor solution was extruded at a flow rate of 12 ml / min at a pressure of 0.8 MPa. Pushed apart and a gap between the blade 25 and the cylindrical metal mold 29.

  Next, the nozzle 23 and the blade 25 were moved in the direction of arrow A at a speed of 60 mm / min. At the time of application, uncoated portions of 5 mm each were provided at both ends of the cylindrical mold 29. Thereafter, the cylindrical mold 29 was kept horizontal and rotated at 6 rpm while being heated and dried at 120 ° C. for 35 minutes, and then heated at 360 ° C. for 30 minutes to form a polyimide resin film.

(Preparation of evaluation sample for reinforcing layer)
A 500 mass% solution of a polyimide precursor prepared by synthesizing 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether in N-methyl-2-pyrrolidone 500 10 parts by mass of carbon black (SPECIAL BLACK 4 (manufactured by Degussa)) was added and dispersed in a sand mill for 6 hours at room temperature. Was applied to the cylindrical mold 29 in the same manner as the above, and then heated and dried at 120 ° C. for 35 minutes while rotating the cylindrical mold 29 at 6 rpm while being horizontal, and then heated at 360 ° C. for 30 minutes. Thus, a polyimide resin film was formed.

<Measurement of tensile yield strain>
From the base material part and the reinforcing layer part obtained as described above, a test piece (width 5 mm) was produced by punching with dumbbell No. 3, and using a MODEL-1605N manufactured by Aiko Engineering Co., Ltd., at a tensile speed of 20 mm / min. The measurement was made 5 times, and the average value was taken as the measurement value. The tensile yield strength was measured in an environment with a temperature of 22.5 ± 0.5 ° C. and a humidity of 55 ± 2%.
As a result, the obtained tensile yield strain was 37% for the base material portion and 48% for the reinforcing layer portion.

<MIT test>
The number of folding times is measured in accordance with JIS P8115 (1994), using a MIT testing machine shown in FIG. 5 with a material width of 15 mm and a tension of 9.8 N (1 kgf). The above formulas (1) and (2) The number of folding times was determined by the formula. A test piece having a length of 130 mm and a width of 15 mm was prepared from the polyimide resin film of the base material part and the polyimide resin film of the reinforcing layer part obtained as described above, and measurement was performed 5 times each, and the average value was measured. It was. Table 1 shows the physical properties of the base material portion and the reinforcing layer portion.

[Examples 2 to 4]
In Example 1, the endless belt and the mechanical member were the same as in Example 1 except that the amount of carbon black added to the polyimide precursor solution for preparing the reinforcing layer was changed to 5 parts by mass, 15 parts by mass, and 0 parts by mass. The resin film of the reinforcement layer part single-piece | unit for performing characteristic evaluation was produced, and it was set as Example 2, Example 3, and Example 4, respectively.
In the same manner as in Example 1, the mechanical properties of the obtained endless belt and resin film were evaluated. The durability test was also performed in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 1]
In Example 1, except that the amount of carbon black added to the polyimide precursor solution for preparing the reinforcing layer was 20 parts by mass, the protrusion-formed endless belt and mechanical property evaluation were performed in the same manner as in Example 1. For this reason, a resin film having a single reinforcing layer portion was prepared as Comparative Example 1.
In the same manner as in Example 1, the mechanical properties of the obtained endless belt and resin film were evaluated. The durability test was also performed in the same manner as in the examples. The results are shown in Table 1.

[Comparative Example 2] (Endless belt without reinforcing layer)
After producing a polyimide resin film by the same method as that for producing the base material of Example 1, both ends were trimmed to a width of 350 mm. Next, as an adhesive, a urethane resin (Tigers Polymer Co., Ltd. typelen TR100-70 (trade name)) of JIS K6253 (1997) type A durometer hardness A70 / S having a width of 5 mm and a height of 15 mm is used. Liquid room temperature curing type adhesive CEMEDINE Super XNo. A protrusion was formed by applying 8008 applied so as not to protrude from the adhesive surface to the inner peripheral surfaces of both end portions in the width direction of the polyimide resin film. The durability test was performed in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 3] (Belt reinforced with reinforcing tape)
After producing a polyimide resin film by the same method as that for producing the base material of Example 1, both ends were trimmed to a width of 350 mm. Thereafter, a polyester tape (model number NC31C manufactured by Nitto Denko) was bonded to the surfaces of both ends of the polyimide film to reinforce. Next, one part as an adhesive to urethane resin (Tigers Polymer Co., Ltd. typelen TR100-70 (trade name)) of JISK6253 (1997) type A durometer hardness A70 / S having a width of 5 mm and a height of 15 mm. Room temperature curable adhesive Cemedine Super XNo. A protrusion was formed by applying 8008 applied so as not to protrude from the adhesive surface to the inner peripheral surfaces of both end portions in the width direction of the polyimide resin film. The durability test was performed in the same manner as in Example 1. The results are shown in Table 1.

[Example 5] (Change of drying condition of substrate)
(Preparation of base material)
A polyimide resin film was produced in the same manner as in Example 1 except that the drying conditions were changed to 120 ° C. for 30 minutes in the production of the base material of Example 1. After drying, a part of the obtained polyimide resin film was cut out, and the amount of residual solvent in the film was measured with a thermogravimetric measuring device DTG-50 manufactured by Shimadzu Corporation. As a result, it was 47% by mass.

(Production of reinforcement layer)
Then, after spin-coating a carbon black-dispersed polyimide precursor solution on 33 mm on both ends of the polyimide resin film in the same manner as in Example 1, heating and drying at 120 ° C. for 35 minutes, heating at 360 ° C. for 30 minutes, A polyimide resin film was formed. The width of the polyimide resin film removed from the cylindrical mold 29 was adjusted to 350 mm.

(Production of protrusions)
Next, one part as an adhesive to urethane resin (Tigers Polymer Co., Ltd. typelen TR100-70 (trade name)) of JISK6253 (1997) type A durometer hardness A70 / S having a width of 5 mm and a height of 15 mm. Room temperature curable adhesive Cemedine Super XNo. An endless belt of Example 5 was obtained by pasting 8008 applied so as not to protrude from the adhesive surface to the inner peripheral surface of both end portions in the width direction of the polyimide resin film to form protrusions.

(Durability test)
The obtained endless belt was used as an intermediate transfer belt of the tandem type image forming apparatus shown in FIG. The evaluation results are shown in Table 2.

(Evaluation of mechanical properties)
A punched specimen (width 5 mm) of dumbbell No. 3 was prepared from the polyimide resin film of the base material part obtained by the method described in the preparation of the base material, and a tensile speed was obtained using MODEL-1605N manufactured by Aiko Engineering Co., Ltd. Measurement was performed 5 times at 20 mm / min, and the average value was taken as the measured value. The tensile yield strength was measured in an environment with a temperature of 22.5 ± 0.5 ° C. and a humidity of 55 ± 2%. As a result, the obtained tensile yield strain was 34% by mass.
In addition, the mechanical properties of the obtained endless belt and resin film were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Example 6]
A polyimide precursor film was produced in the same manner as in Example 1 except that the drying conditions were changed to 120 ° C. for 45 minutes in the production of the base material of Example 1. Thereafter, a reinforcing layer and protrusions were formed in the same manner as in Example 1 and then used as an intermediate transfer belt of the tandem type image forming apparatus shown in FIG. In addition, from the polyimide resin film obtained by heating the polyimide precursor film obtained by the above method at 360 ° C. for 30 minutes, a test piece was prepared in the same manner as in Example 1, and the tensile test and the MIT test were performed. I did it. The evaluation results are shown in Table 2.

[Examples 7 and 8]
After forming the polyimide precursor film in the same manner as in Example 1 except that the drying conditions were changed to 180 ° C. for 30 minutes and 120 ° C. for 25 minutes in the production of the base material of Example 1, the same as in Example 1 In this manner, a reinforcing layer and a protrusion were formed, which were designated as Example 7 and Example 8, respectively.
In Example 8, since the shape of the polyimide precursor film was not stable when the reinforcing layer was produced, the difference between the maximum value and the minimum value of the end film thickness of the polyimide resin film after forming the reinforcing layer was about 15 μm. It became bigger.
Next, a durability test was performed using the intermediate transfer belt of the tandem type image forming apparatus shown in FIG. Moreover, the test piece was produced from the polyimide resin film obtained by heating the polyimide precursor film | membrane obtained by the said method at 360 degreeC for 30 minutes, and the tension test and the MIT test were done. The evaluation results are shown in Table 2.

[Example 9]
(Production method of polyamide-imide belt)
(Preparation of base material)
An equivalent of trimellitic anhydride and 4,4′-diaminodiphenylmethane is dissolved in N-methyl-2-pyrrolidone to prepare a polyamideimide solution having a solid content of 20% by mass, and carbon black (SPECIAL BLACK) is prepared therein. 4 (manufactured by Degussa) was added in an amount of 22 parts by mass, and dispersed with a sand mill for 6 hours at room temperature, and the viscosity of this carbon black-dispersed polyamideimide solution was 45 Pa · s at room temperature (22 ° C.).
On the other hand, an aluminum cylindrical mold having an outer diameter of 200 mm, a length of 400 mm, and a surface roughened by blasting to Ra 0.8 μm is prepared, and a silicone mold release agent (trade name: KS700, Shin-Etsu Chemical Co., Ltd.) is provided on the outer surface. Made) and baked at 300 ° C. for 1 hour.
Furthermore, as a spin coating process, as shown in FIG. 6, the axial direction of the cylindrical mold 29 was horizontal and rotated at 40 rpm. The blade 25 is made of polyethylene having a width of 220 mm and a thickness of 1 mm, and has elasticity. This was pressed against a cylindrical mold 29, and the polyamideimide precursor solution 26 was extruded from the container 22 through a nozzle 23 having a diameter of 3 mm at an air pressure of 0.8 MPa and a flow rate of 12 ml / min. When the polyamideimide solution passed through the blade 25, the blade 25 was expanded and a gap was formed between the blade 25 and the cylindrical mold 29.

  Next, the nozzle 23 and the blade 25 were moved in the direction of arrow A at a speed of 60 mm / min. Subsequently, the cylindrical mold 29 coated with the polyamideimide precursor solution 26 was heated and dried at 120 ° C. for 20 minutes while rotating at 6 rpm while being horizontal. After drying, a part of the obtained polyamide-imide resin film was cut out and the amount of residual solvent in the film was measured with a thermogravimetric measuring device DTG-50 manufactured by Shimadzu Corporation.

(Production of reinforcement layer)
Thereafter, carbon black-dispersed polyamideimide obtained by adding 10 parts by mass of the above-mentioned carbon black to a 20% by weight concentration solution of the above-mentioned polyamideimide at 33 mm on both ends of the membrane obtained by drying, and dispersing for 6 hours with a sand mill. The solution was spin coated. The application conditions of the polyamideimide 20% by weight concentration solution were the same as those when the above-described carbon black-dispersed polyamideimide solution was applied. Thereafter, the cylindrical mold 29 was kept horizontal and rotated at 6 rpm while being heated and dried at 120 ° C. for 20 minutes, and then heated at 240 ° C. for 25 minutes to form a polyamideimide resin film. The width of the polyamideimide resin film removed from the cylindrical mold 29 was adjusted to 350 mm.

<Preparation of mechanical property evaluation sample>
An evaluation sample of mechanical properties was produced by the following method.

(Preparation of evaluation sample of base material)
An equivalent of trimellitic anhydride and 4,4′-diaminodiphenylmethane is dissolved in N-methyl-2-pyrrolidone to prepare a polyamideimide solution having a solid content of 20% by mass, and carbon black (SPECIAL BLACK) is prepared therein. 22 (manufactured by Degussa) was added and dispersed in a sand mill at room temperature for 6 hours, and as a spin coating process, as shown in FIG. The blade 25 is made of polyethylene having a width of 220 mm and a thickness of 1 mm, and has elasticity, which is pressed against the cylindrical mold 29, and the polyamideimide precursor solution 26 has a diameter of 3 mm from the container 22. Extrusion was performed through the nozzle 23 at an air pressure of 0.8 MPa and a flow rate of 12 ml / min. When passing through the blade 25 is widened and a gap between the blade 25 and the cylindrical metal mold 29.
Next, the nozzle 23 and the blade 25 were moved in the direction of arrow A at a speed of 60 mm / min. Next, the cylindrical mold 29 coated with the polyamideimide precursor solution 26 is kept horizontal and rotated at 6 rpm while being heated and dried at 120 ° C. for 20 minutes, and then heated at 240 ° C. for 25 minutes to obtain a polyamideimide resin. A film was formed.

(Preparation of evaluation sample for reinforcing layer)
An equivalent of trimellitic anhydride and 4,4′-diaminodiphenylmethane is dissolved in N-methyl-2-pyrrolidone to prepare a polyamideimide solution having a solid content of 20% by mass, and carbon black (SPECIAL BLACK) is prepared therein. 4 (manufactured by Degussa) was added and dispersed in a sand mill for 6 hours at room temperature, and this carbon black-dispersed polyamideimide solution was applied to a cylindrical molded tube in the same manner as when the substrate was prepared, Then, the cylindrical molded tube was heated and dried at 120 ° C. for 20 minutes while rotating horizontally at 6 rpm, and further heated at 240 ° C. for 30 minutes to form a polyamideimide resin film.

(Production of protrusions)
Next, as an adhesive, a urethane resin (Tigers Polymer Co., Ltd. typelen TR100-70 (trade name)) of JIS K6253 (1997) type A durometer hardness A70 / S having a width of 5 mm and a height of 15 mm is used. Liquid room temperature curing type adhesive CEMEDINE Super XNo. A protrusion coated with 8008 applied so as not to protrude from the adhesive surface was affixed to the inner peripheral surface of both ends in the width direction of the polyimide resin film to form a protrusion-formed endless belt.
Thereafter, a durability test was conducted using the intermediate transfer belt of the tandem type image forming apparatus shown in FIG. As a result, it was not broken in a durability test of 2.8 × 10 ⁵ rotations.

<Evaluation of mechanical properties>
The mechanical properties were evaluated in the same manner as in Example 1 by conducting the tensile yield strain, tensile strength, and MIT test of the base material portion and the reinforcing layer portion. The evaluation results are shown in Table 3.

[Examples 10 to 12]
In the production of the reinforcing layer of Example 9, the endless belt and the mechanical properties were evaluated in the same manner as in Example 9 except that the amount of carbon black added to the polyamideimide solution was 5 parts by mass, 15 parts by mass, and 0 parts by mass. A polyamideimide resin film having a single reinforcing layer portion to be prepared was prepared as Example 10, Example 11, and Example 12, respectively.
In the same manner as in Example 1, the mechanical properties of the obtained endless belt and resin film were evaluated. The durability test was also performed in the same manner as in Example 1. The results are shown in Table 3.

[Comparative Example 4]
In the production of the reinforcing layer of Example 9, an endless belt and a single layer of the reinforcing layer for evaluating mechanical properties were obtained in the same manner as in Example 9 except that the amount of carbon black added to the polyamideimide solution was 22 parts by mass. A polyamideimide resin film was prepared and used as Comparative Example 4.
In the same manner as in Example 1, the mechanical properties of the obtained endless belt and resin film were evaluated. The durability test was also performed in the same manner as in Example 1. The results are shown in Table 3.

[Example 13]
A polyamide-imide resin film was prepared in the same manner as in Example 9 except that the drying conditions were changed to 120 ° C. for 16 minutes in the production of the base material of Example 9. After drying, a part of the obtained polyamideimide resin film was cut out, and the amount of residual solvent in the film was measured with a thermogravimetric measuring device DTG-50 manufactured by Shimadzu Corporation. As a result, it was 45% by mass.
A reinforcing layer and protrusions were produced on both ends of the polyamideimide resin film obtained as described above in the same manner as in Example 9 to obtain a protrusion-forming endless belt. Thereafter, a durability test was conducted using the intermediate transfer belt of the tandem type image forming apparatus shown in FIG. Moreover, a test piece was cut out from the polyamideimide resin film obtained in the same manner as described above, and a tensile test and an MIT test were performed. The evaluation results are shown in Table 3.

[Example 14]
A polyamide-imide resin film was prepared in the same manner as in Example 9 except that the drying condition was changed to 120 ° C. for 25 minutes in the production of the base material of Example 9. After drying, a part of the obtained polyamide-imide resin film was cut out, and the amount of residual solvent in the film was measured with a thermogravimetry apparatus DTG-50 manufactured by Shimadzu Corporation. As a result, it was 34% by mass.
A reinforcing layer and protrusions were produced on both ends of the polyamideimide resin film obtained as described above in the same manner as in Example 9 to obtain a protrusion-forming endless belt. Thereafter, a durability test was conducted using the intermediate transfer belt of the tandem type image forming apparatus shown in FIG. Moreover, a test piece was cut out from the polyamideimide resin film obtained in the same manner as described above, and a tensile test and an MIT test were performed. The evaluation results are shown in Table 3.

[Examples 15 and 16]
A polyamideimide resin film was formed in the same manner as in Example 9 except that the drying conditions were changed to 135 ° C. for 25 minutes and 100 ° C. for 19 minutes in the production of the base material of Example 9, and then Example 9 and In the same manner, a reinforcing layer and a protruding portion were formed, and were set as Example 15 and Example 16, respectively. In Example 16, since the shape of the polyamideimide resin film was not stable at the time of preparing the reinforcing layer, the difference between the maximum value and the minimum value of the end film thickness of the polyamideimide resin film after forming the reinforcing layer was about 15 μm. It became bigger.
Next, a durability test was performed using the intermediate transfer belt of the tandem type image forming apparatus shown in FIG. Moreover, a test piece was produced from the polyamideimide resin film of the base material part obtained by the above method, and a tensile test and an MIT test were performed. The evaluation results are shown in Table 3.

  From the above results, the endless belts of Examples 1 to 16 can withstand long-time use and are extremely excellent in durability.

It is a figure which shows the outline of the endless belt of this invention. It is a figure which shows a mode when the endless belt of this invention is stretched around the roll. It is sectional drawing which shows a mode when the endless belt of this invention is stretched around the roll. It is sectional drawing of the endless belt of this invention. It is a figure which shows the outline of a MIT testing machine. It is a figure explaining the coating device for flow coat methods. FIG. 3 is a schematic diagram illustrating a main part of a tandem image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Endless belt 12 Base material 14 Protrusion part 16 Reinforcement layer 23 Nozzle 25 Blade 26 Polyimide precursor solution 29 Cylindrical metal mold 31 Toner cartridge 32 Fixing roll 33 Backup roll 34 Tension roll 35 Secondary transfer roll 38 Laser generator 39 Photoconductor 40 Primary transfer roll 41 Drive roll 42 Transfer cleaner 43 Charging roll 44 Photoconductor cleaner 45 Developer 46 Intermediate transfer belt

Claims (11)

A base material containing a filler and a resin; a protrusion provided on one or both ends in the width direction of the base material on the inner peripheral surface side of the base; and the protrusion through the base material A reinforcing layer provided on the outer peripheral surface side of the position opposite to
The reinforcing layer includes, as a main component, a resin composed of the same monomer as the monomer constituting the resin contained as a main component in the base material,
An endless belt characterized in that a tensile yield strain in the circumferential direction of the reinforcing layer is larger than a tensile yield strain in the circumferential direction of the base material.   2. The endless belt according to claim 1, wherein the filler content of the base material is larger than the filler content of the reinforcing layer.   The endless belt according to claim 1 or 2, wherein a tensile yield strain in the circumferential direction of the reinforcing layer is 110% or more and 150% or less of a tensile yield strain in the circumferential direction of the base material. .   The number of times of folding resistance of the reinforcing layer according to the MIT test method is 105% to 200% of the number of times of folding resistance of the base material according to the MIT test method. Endless belt as described in.   The endless belt according to any one of claims 1 to 4, wherein the reinforcing layer is endless in a circumferential direction of the endless belt. On the outer peripheral surface of the cylindrical mold, a resin film forming step for forming a resin film as a base material,
A reinforcing layer forming step of forming a reinforcing layer at one end or both ends in the width direction of the resin film;
A protrusion forming step of forming a protrusion on a surface opposite to the surface on which the reinforcing layer is formed via the resin film;
6. The method of manufacturing an endless belt according to claim 1, wherein the endless belt is provided. In the resin film forming step and the reinforcing layer forming step,
After applying a polyimide precursor solution or a polyamideimide solution containing a filler on the outer peripheral surface of a cylindrical mold to obtain a coating film, the coating film is dried to form a dry film for forming a substrate,
Then, after applying a polyimide precursor solution or a polyamideimide solution of the same type as the resin of the base material to the dry film surface to obtain a coating film, the coating film is dried to form a dry film for a reinforcing layer. Forming,
The method for producing an endless belt according to claim 6, wherein the dry film for forming the base material and the dry film for forming the reinforcing layer are simultaneously imide-converted.   The method for producing an endless belt according to claim 7, wherein the amount of residual solvent in the dry film for forming the base material is 30% by mass or more and 60% by mass or less with respect to the total mass of the dry film. .   An image forming apparatus comprising the endless belt according to any one of claims 1 to 5. A regulating member that regulates the movement of the protrusion provided on the endless belt;
The image forming apparatus according to claim 9, wherein the meandering of the endless belt is regulated by regulating the protrusion by the regulating member.   A charging device, an exposure device, a developing device, a transfer device, a transport device, and a fixing device, wherein the endless belt is provided in at least one of the transfer device, the transport device, and the fixing device; The image forming apparatus according to claim 9, wherein the image forming apparatus is an image forming apparatus.

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