JP4480074B2 - Seamless belt for electrophotography, its manufacturing method, coating liquid, electrophotographic apparatus - Google Patents

Description

  The present invention relates to a seamless belt, and more particularly to a seamless belt used in a belt constituting unit equipped in an electrophotographic apparatus such as a copy printer.

  Conventionally, a solution containing a polyimide precursor or a polyamideimide precursor is applied and cast on a support (molding mold: rotating body, belt, etc.) to form a coating film (thin film), and then the precursor is heated. In the process of accelerating imidization, “coated skin or turtle shell pattern (hereinafter abbreviated to“ Yuzu skin or turtle shell pattern ”)” occurs on the surface of the thin film, or when a solution is applied, the substrate to be coated It is known that the material is unfamiliar with the material and causes a “flick” defect.

In order to improve such problems, for example, the following methods have been proposed.
It has been proposed to prevent itching by adding a fluorosurfactant to a polyimide, polyamideimide or polyamic acid solution (Patent Document 1). Further, it has been proposed to prevent repelling by including a surfactant containing a siloxane unit in the polyimide precursor solution (Patent Document 2). In addition, by adding a fluorosurfactant to a heat-resistant resin (polyimide resin, polyamideimide resin, polyamide resin) solution in which a filler is dispersed, repelling at the time of coating to a substrate (made of tetrafluoropolyethylene) or the like Prevention has been proposed (Patent Document 3). Furthermore, in order to form a semiconductive polyimide endless belt (two-layer structure), a conductive material such as carbon and a solution containing a polyimide precursor are mixed with a fluorosurfactant as a compatibilizing agent to make the conductivity. It has been proposed to improve the dispersion uniformity of substances (Patent Document 4).

According to each of the above proposals, it is possible to avoid the generation of the yuzu skin and the turtle shell pattern and to suppress the repelling.
However, a thick film (for example, 50 μm or more) film containing a filler is formed from a solution (coating liquid) containing a polyimide precursor or a polyamideimide precursor, a filler and a solvent (for example, N-methylpyrrolidone). When forming (for example, the centrifugal molding method), it is necessary to increase the viscosity of the coating liquid and to increase the solid content concentration. However, bubbles are likely to be generated in the coating liquid preparation process in which the filler is dispersed, the coating liquid application process, and the like, and the generated bubbles are difficult to escape. For this reason, there is a problem that bubbles remain in the coating film (coating film) to cause defects.

Moreover, in the use of this invention, it is necessary to fill with a filler in order to provide electrical resistance and thermal conductivity, and this dispersibility also becomes a problem.
Although this point is also described in Patent Document 4, there is a problem that bubbles are likely to be generated in a coating liquid preparation process in which a filler is dispersed, a coating liquid coating process, and the like.
In particular, carbon black is preferably used as the electrical resistance adjusting material. Generally, as a method for improving the dispersibility of carbon black, there is a method of treating carbon black with a coupling agent (Patent Documents 5 to 8). However, the coating solution for a seamless belt of the present invention has a problem that dispersion is still incomplete by this method and the cost is high.
In addition, there is a method of grafting the monomer component in the presence of carbon black (Patent Document 9 and Patent Document 10), but this method has poor grafting efficiency and is used as a coating liquid for the seamless belt of the present invention. It was found that the dispersion of carbon black after grafting was insufficient. Moreover, it has been found that even when the dispersibility in the solution is improved, the surface properties are often disturbed by aggregation during the formation of the coating film.

As a method for producing a polyimide or polyamideimide seamless belt, a molding method in which a coating solution is applied to the inner surface of a cylinder to form a film is widely used. In particular, centrifugal molding in which a cylinder is rotated is generally used. .
Japanese Patent Publication No. 5-8222 JP 2001-302913 A JP 2001-123066 A Japanese Unexamined Patent Publication No. 7-156287 JP-A 63-175869 Japanese Patent Laid-Open No. 63-158666 British Patent No. 1583564 GB 1583411 Specification JP-A 64-6965 German Patent No. 3102823

The present invention solves the above-mentioned problems of the prior art, and is free from defects (surface defects) generated on the surface such as yuzu skin and turtle shell pattern, the filler is uniformly dispersed, no bubbles remain, and smooth. Another object of the present invention is to provide a polyimide or polyamide-imide seamless belt in a film state that is homogeneous and can be efficiently peeled off from a mold.
Furthermore, the present invention provides the seamless belt used in a belt constituent part equipped in an electrophotographic apparatus, a method for producing the seamless belt, a coating liquid used therefor, and a belt constituent part using the seamless belt An object is to provide an electrophotographic apparatus equipped with (in particular, an intermediate transfer belt).

  As a result of intensive studies, the inventors of the present invention supported by using a coating liquid containing an unsaturated carboxylic acid polymer in an organic polar solvent solution of a polyimide precursor or a polyamideimide precursor in which a filler is dispersed. The present inventors have found that the above problem can be improved even when a thick film (for example, 50 μm or more) coating film is formed (for example, centrifugal molding) by applying and casting on a body. Hereinafter, the present invention will be specifically described.

(1) In a seamless belt formed using a coating liquid and containing a filler and polyimide or polyamideimide, the coating liquid includes at least a filler, a polyimide precursor or a polyamideimide precursor, and an organic material. A seamless belt comprising a polar solvent and an unsaturated carboxylic acid polymer.
(2) The seamless belt according to (1), wherein the unsaturated carboxylic acid polymer is a carboxylic acid polymer acid anhydride.
(3) The seamless belt according to (1), wherein the content of the unsaturated carboxylic acid polymer is 0.05 to 1.0 wt% with respect to the filler.
(4) The seamless belt according to any one of (1) to (3), wherein the seamless belt has a film thickness of 50 μm or more.
(5) In a seamless belt for a belt component used in an electrophotographic apparatus for transferring a toner developed image formed on an image carrier and forming an image on a recording medium, the seamless belt for the belt component is ( A seamless belt for a belt component, which is the seamless belt according to any one of 1) to (4).
(6) A plurality of color toner development images sequentially formed on the image carrier are sequentially superimposed on the intermediate transfer belt to perform primary transfer, and the obtained primary transfer images are collectively transferred to a recording medium for secondary transfer. An intermediate transfer belt used in an electrophotographic apparatus, wherein the intermediate transfer belt is constituted by the seamless belt according to any one of (1) to (4).
(7) A seamless belt characterized by producing a seamless belt using a coating liquid containing a filler, a polyimide precursor or a polyamideimide precursor, an organic polar solvent, and an unsaturated carboxylic acid polymer. Production method.
(8) A step of applying and casting a coating liquid containing a filler, a polyimide precursor or a polyamideimide precursor, an organic polar solvent, and an unsaturated carboxylic acid polymer on a support, and a support A step of removing the solvent in the coated and cast coating by heating, a step of further heating and heating to promote imidation of the precursor contained in the coating, and a support for the formed coating A process for producing a seamless belt, comprising a step of releasing from the mold to form a seamless belt.
(9) In an electrophotographic apparatus having a belt component that transfers a toner developed image formed on an image carrier and forms an image on a recording medium, the belt is any one of (1) to (4) An electrophotographic apparatus, which is the seamless belt described in 1.
(10) A plurality of color toner developed images sequentially formed on the image carrier are sequentially superimposed on the intermediate transfer belt to perform primary transfer, and the primary transfer image is collectively transferred to a recording medium. An electrophotographic apparatus having an intermediate transfer belt, wherein the intermediate transfer belt is an intermediate transfer belt constituted by the seamless belt according to any one of (1) to (4).
(11) In a coating liquid for seamless belt production containing a filler and polyimide or polyamideimide, the coating liquid comprises a filler, a polyimide precursor or a polyamideimide precursor, an organic polar solvent, and an unsaturated solvent. A coating liquid for producing a seamless belt, comprising a carboxylic acid polymer.
(12) The coating solution for seamless belt production according to (11), wherein the unsaturated carboxylic acid polymer is a carboxylic acid polymer acid anhydride.

  According to the present invention, it is possible to obtain a seamless belt and an electrophotographic apparatus which are used for electrophotography and the like having the following effects, which improve the problems of the prior art.

According to the invention of (1) or (2), surface defects such as yuzu skin and turtle shell pattern are prevented, the dispersion of the filler is uniform, and smooth and homogeneous heat resistance without bubbles remaining is excellent. A seamless belt is provided. And because it has excellent surface uniformity and no defects such as bubbles, it is durable for electrophotographic drive members equipped in electrophotographic devices that are subject to severe mechanical and electrical hazards, that is, belt components. It can be used as an excellent member.
According to the invention of (3), when forming a seamless belt, the effect of preventing the generation of the yuzu skin and the turtle shell pattern is further improved, the occurrence of the repelling phenomenon at the time of coating, In addition, it is possible to suppress the appearance of a wind pattern during drying by a hot air circulating dryer. Furthermore, the releasability from the mold is improved, and the seamless belt can be taken out without being damaged.
According to the invention of (4), various performances required for the belt constituent part equipped in the electrophotographic apparatus, for example, durability against mechanical / electrical repetitive hazards and stability of physical dimensions are satisfied and suitable. Become. Even in the case of a thick film of 50 μm or more, an excellent seamless belt can be provided.
According to the invention of (5), it is possible to improve durability against repeated mechanical and electrical severe hazards.
According to the invention of (6), it is possible to improve durability against repeated mechanical and electrical severe hazards.
According to the invention of (7) or (8), even in the case of a thick film (50 μm or more), there are no surface defects such as yuzu skin and turtle shell pattern, the dispersion of the filler is uniform, and there is no air bubbles. A seamless belt is provided.
According to the invention of (9) or (10), durability is improved, and a high-quality image can be stably provided even in image formation over a long period of time.
According to the invention of (11) or (12), even when the film thickness is 50 μm or more, there is no surface defects (such as yuzu skin and turtle shell pattern), the dispersion of the filler is uniformed, and no bubbles remain. It is possible to provide a smooth and uniform seamless belt.

  Molding of a seamless belt containing the filler of the present invention and polyimide or polyamideimide is a coating liquid containing a filler, a polyimide precursor or a polyamideimide precursor, an organic polar solvent, and an unsaturated carboxylic acid polymer. It is done using.

Hereinafter, the coating liquid will be described.
As described above, in the case of using a coating liquid prepared by simply using a filler, a polyimide precursor or a polyamideimide precursor, and a solvent (for example, N-methylpyrrolidone) as a component, thin film formation (centrifugation) When molding, etc.), the surface of the coating film becomes rough, such as a yuzu skin or a turtle shell pattern. This roughness adversely affects the dispersibility of the filler, resulting in non-uniform dispersion. In particular, when the filler is an electric resistance adjusting material (substantially, resistance adjusting material), if the dispersion is non-uniform, the resistance value also becomes non-uniform, and the seamless belt for the belt constituent part equipped in the electrophotographic apparatus described later is used. For example, a seamless belt that forms an image such as an intermediate transfer belt causes abnormal images. In addition, if a heating and heating process is performed to imidize the precursor while maintaining such a rough surface state, minute cracks are generated. When such micro cracks are formed, for example, when used for a drive member equipped in an electrophotographic apparatus, that is, a member for a belt component, it causes a belt crack in repeated use and lacks durability. Become.

  Furthermore, it is necessary to peel from the mold after the final firing step. Usually, the mold is subjected to a treatment that is easy to release, but the effect of the release layer may be reduced during repeated use at 250 ° C. or higher, making it difficult to release. Further, when meeting the demand for high mechanical durability such as the use of the present invention, the material system is more difficult to release.

Therefore, in the present invention, even in the case of forming a thick film (50 μm or more), the surface is not rough (Yuzu skin, turtle shell pattern, etc.), the filler is uniformly dispersed, and the generation of bubbles is suppressed. At the same time, in order to prevent crack formation, the problem is solved by including an unsaturated carboxylic acid polymer as a component of the coating liquid.
The unsaturated carboxylic acid polymer of the present invention is a polymer having an unsaturated bond and having a carbonyl group, such as an unsaturated polyester. By having a carbonyl group, the affinity with the filler is improved and the dispersibility is improved.
In order to disperse the unsaturated carboxylic acid polymer preferably, the acid value of the unsaturated carboxylic acid polymer is preferably 10 to 700 mgKOH / g.
Since NMP, DMF, DMAc, etc. are generally used for the resin solution of the polyimide or polyamideimide precursor, the unsaturated carboxylic acid polymer needs to be dissolved in these solvents. Further, the unsaturated carboxylic acid polymer needs to have high affinity with polyimide and polyamideimide resin. If the affinity with these resins is poor, the filler aggregates during dry film formation, which adversely affects electrical and mechanical properties.
It is preferable to have an acid anhydride structure such as maleic acid from the viewpoint of affinity with polyimide and polyamideimide resin.
Further, silicone oil or a surfactant may be used in combination in order to further prevent the formation of yuzu skin and turtle shell pattern.

Next, the filler contained as a component of the coating liquid of the present invention will be described.
As the filler, inorganic or organic materials of various materials and forms are used as necessary in order to obtain desired characteristics according to the purpose such as a reinforcing material, a lubricant, a heat conduction material, and a resistance control material. In particular, an inorganic filler is often used to heat and dry at a high temperature during film formation.
Moreover, what added the organic substance to the inorganic filler is also used.
In addition, a filler comprises a coating liquid in the state disperse | distributed to the organic polar solvent solution (containing the siloxane compound used for this invention) of a polyimide precursor or a polyamideimide precursor.
When a reinforcing material is used as the filler, for example, one or more selected from carbon black, silica, glass fiber, carbon fiber, aromatic polyamide fiber, silicon carbide fiber, potassium titanate fiber, glass beads and the like may be used. it can. In addition, a solid lubricant can be used for the purpose of adding or improving slipperiness, and for example, one or more selected from molybdenum disulfide, graphite, boron nitride, lead monoxide, lead powder and the like can be used.
In addition, one or more generally known additives such as an antioxidant, a heat stabilizer, an ultraviolet absorber, a lubricant, and a colorant can be added without departing from the object of the present invention.

When used as a seamless belt in the present invention, particularly as a seamless belt (electrophotographic seamless belt) for a belt component (driving unit) equipped in an electrophotographic apparatus, various components can be used depending on the application. However, the reinforcing material as described above is indispensable particularly from the viewpoint of mechanical strength.
In addition, examples of the electrophotographic seamless belt (electrophotographic seamless belt) used in the belt constituting unit provided in the electrophotographic apparatus include an intermediate transfer belt, a transfer conveyance belt, and a fixing belt. When used as a fixing belt, it is necessary to add a heat conductive material having high thermal conductivity. On the other hand, when used as a transfer conveying belt or an intermediate transfer belt, a resistance control material for controlling electric resistance. Is necessary.

  As the resistance control material, carbon black, graphite, or metal such as copper, tin, aluminum, indium, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin oxide doped with antimony, Examples thereof include fine metal oxide powders such as indium oxide doped with tin. In addition, as an ion conductive resistance control material, tetraalkylammonium salt, trialkylbenzyl, ammonium salt, alkylsulfonate, alkylbenzenesulfonate, alkylsulfate, glycerol fatty acid ester, sorbitan fatty acid ester, polyoxyethylene alkylamine Polyoxyethylene fatty alcohol ester, alkyl betaine, lithium perchlorate and the like may be used in combination. In addition, the resistance control material in this invention is not limited to these exemplary compounds.

Further, in the case of a coating liquid comprising the polyimide precursor or polyamideimide precursor of the present invention and an organic polar solvent such as N-methylpyrrolidone, carbon black is preferably used among the resistance control materials. It is done.
In general, carbon black has high cohesion between particles and weak affinity with resin components and solvents, so it is very difficult to uniformly mix or disperse, and it is necessary to take some measures.
For example, by reacting the surface functional group of carbon black with an organic compound having reactivity with the functional group, the affinity with the resin component and the solvent is increased, and it can be uniformly mixed or dispersed. It becomes like this.
Examples of the organic compound include vinyl acetate, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, p-methoxystyrene, p-bromostyrene, p-chlorostyrene, and p-styrene. Styrene compounds such as sodium sulfonate, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, glycidyl acrylate and other acrylate compounds, methyl methacrylate, methacryl Methacrylic acid ester compounds such as ethyl acetate, n-propyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, N-substituted acrylates such as acrylonitrile, acrylamide, N-isopropylacrylamide, N-piperylacrylamide Riruamido compounds, divinyl benzene, methylene bisacrylamide, 1,3-butane diol but dimethacrylate crosslinking monomer, etc. and the like, but is not limited thereto.

  Incidentally, as a method for improving the dispersibility of carbon black, there is a method of treating carbon black with a coupling agent (see Patent Documents 5 to 8). There is a problem that it is incomplete and the cost is high. Also, there is a method of grafting monomer components in the presence of carbon black (Patent Document 9 and Patent Document 10), but this method has poor grafting efficiency. In the coating liquid of the present invention, after grafting, The carbon black was not sufficiently dispersed.

Next, the polyimide precursor or polyamideimide precursor which is the composition of the coating liquid in the present invention and the polyimide or polyamideimide produced by heat treatment (imidization) of the precursor will be described in detail.
Hereinafter, description will be made in the order of polyimide and polyamideimide.

<Polyimide>
The polyimide used in the present invention is obtained via a polyamic acid (polyimide precursor) by a reaction between a generally known aromatic polycarboxylic acid anhydride or derivative thereof and an aromatic diamine. That is, polyimide is insoluble in solvents and the like due to its rigid main chain structure and has an infusible property. Therefore, a polyimide precursor that is soluble in an organic solvent from an acid anhydride and an aromatic diamine ( Polyamic acid or polyamic acid) is synthesized, and at this stage, molding is performed by various methods, and then the polyamic acid is subjected to dehydration reaction by heating or a chemical method to be cyclized (imidized) to obtain polyimide. The outline of the reaction is shown in the following formula (1).

(In the formula, Ar ¹ represents a tetravalent aromatic residue containing at least one carbon 6-membered ring, and Ar ² represents a divalent aromatic residue containing at least one carbon 6-membered ring.)

  Specific examples of the aromatic polyvalent carboxylic acid anhydride include, for example, ethylenetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4 ′. -Benzophenone tetracarboxylic dianhydride, 2,2 ', 3,3'-benzophenone tetracarboxylic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic dianhydride, 2,2 ', 3,3′-biphenyltetracarboxylic dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3 , 4-Dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride Bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxylphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 2 , 3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,2 , 3,4-benzenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7 , 8-phenanthrenetetracarboxylic dianhydride and the like. These may be used alone or in combination of two or more.

  Next, specific examples of the aromatic diamine to be reacted with the aromatic polycarboxylic acid anhydride include, for example, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, and p-aminobenzyl. Amine, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, bis (3-aminophenyl) sulfide, (3-aminophenyl) (4-aminophenyl) sulfide, bis (4-aminophenyl) sulfide, bis (3-aminophenyl) sulfide, (3-aminophenyl) (4-aminophenyl) sulfoxide, bis (3-aminophenyl) sulfone, (3-aminophenyl) (4-amino Phenyl) sulfone, bis (4-aminophenyl) Ruhon, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, Bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (3-aminophenoxy) phenyl] ethane, 1,1- Bis [4- (4-aminophenoxy) phenyl] -ethane, 1,2-bis [4- (3-aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) ) Phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] butane, 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3 3-hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 1,3-bis (3-aminophenoxy) Benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (3- Aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] Ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfoxide, bis [4- (4 -Aminophenoxy) phenyl] sulfoxide, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, Bis [4- (4-aminophenoxy) phenyl] ether, 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 4,4′-bis [3- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4′- [3- (3-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4′-bis [4- (4 -Amino-α, α-dimethylbenzyl) phenoxy] diphenylsulfone, bis [4- {4- (4-aminophenoxy) phenoxy} phenyl] sulfone, 1,4-bis [4- (4-aminophenoxy) phenoxy] -Α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene, and the like. These are used individually or in mixture of 2 or more types.

A polyimide precursor (polyamic acid) can be obtained by carrying out a polymerization reaction in an organic polar solvent using substantially equimolar amounts of the aromatic polycarboxylic anhydride component and the diamine component. Below, the manufacturing method of a polyamic acid is demonstrated concretely.
Examples of the organic polar solvent used in the polymerization reaction of polyamic acid include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide, N , N-dimethylacetamide, N, N-diethylacetamide and other acetamide solvents, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone and other pyrrolidone solvents, phenol, o-, m-, or p- Phenol solvents such as cresol, xylenol, halogenated phenol, catechol, ether solvents such as tetrahydrofuran, dioxane, dioxolane, alcohol solvents such as methanol, ethanol, butanol, cellosolve such as butyl cellosolve or hexa Chill phosphoramide, .gamma.-butyrolactone, etc. may be mentioned, it is desirable to use them alone or as a mixed solvent. The solvent is not particularly limited as long as it dissolves polyamic acid, but N, N-dimethylacetamide and N-methyl-2-pyrrolidone are particularly preferable.

As an example for producing a polyimide precursor, first, one or more kinds of diamines are dissolved in the above organic solvent or dispersed in a slurry state in an inert gas atmosphere such as argon or nitrogen. When at least one aromatic polycarboxylic acid anhydride or derivative thereof is added to this solution (either in a solid state, in a solution state dissolved in an organic solvent, or in a slurry state), it generates heat. A ring-opening polyaddition reaction occurs, and the viscosity of the solution rapidly increases, and a high molecular weight polyamic acid solution is obtained. The reaction temperature at this time is preferably controlled to −20 ° C. to 100 ° C., desirably 60 ° C. or less. The reaction time is about 30 minutes to 12 hours.
The above is an example. Contrary to the addition procedure in the reaction, the aromatic polycarboxylic acid anhydride or derivative thereof is first dissolved or diffused in an organic solvent, and the diamine may be added to this solution. Good. The diamine may be added in a solid state, in a solution state dissolved in an organic solvent, or in a slurry state. That is, the mixing order of the acid dianhydride component and the diamine component is not limited. Further, the aromatic tetracarboxylic dianhydride and the aromatic diamine may be simultaneously added to the organic polar solvent for reaction.
As described above, an aromatic polyvalent carboxylic acid anhydride or derivative thereof and an aromatic diamine component are polymerized in about an equimolar amount in an organic polar solvent, so that the polyamic acid is uniformly dispersed in the organic polar solvent. A polyimide precursor solution is obtained in a dissolved state.

As the polyimide precursor solution (polyamic acid solution) in the present invention, the one synthesized as described above can be used, but the so-called polyamic acid composition is simply dissolved in an organic solvent. What is marketed as a polyimide varnish can also be obtained and used.
Examples of this include Trenys (manufactured by Toray Industries, Inc.), U-Varnish (manufactured by Ube Industries), Rika Coat (manufactured by Nippon Nippon Chemical Co., Ltd.), Optmer (manufactured by JSR), SE812 (manufactured by Nissan Chemical Industries, Ltd.), CRC8000 ( Sumitomo Bakelite Co., Ltd.) is a typical example.

  The inorganic filler is mixed and dispersed in the synthesized or obtained polyamic acid solution, and the unsaturated carboxylic acid polymer in the present invention is added and mixed to prepare a coating solution. The coating liquid is applied to a support (molding mold) as described later, and then subjected to a treatment such as heating, whereby conversion (imidation) from polyamic acid, which is a polyimide precursor, to polyimide is performed.

That is, the polyamic acid can be imidized by a heating method (1) or a chemical method (2). The heating method (1) is a method of converting polyamic acid to polyimide by heat treatment at 200 to 350 ° C., and is a simple and practical method for obtaining polyimide (polyimide resin). On the other hand, the chemical method (2) is a method in which a polyamic acid is reacted with a dehydrating cyclization reagent (such as a mixture of a carboxylic acid anhydride and a tertiary amine) and then heat-treated to completely imidize, (1 The method (1) is often used because the method is more complicated and costly than the method of heating.
In order to exhibit the intrinsic performance of polyimide, it is necessary to complete imidization by heating to a temperature above the glass transition temperature of the corresponding polyimide.

The progress of imidization (degree of imidization) can be evaluated by a commonly performed method for measuring the imidization rate.
As a method for measuring such an imidization rate, for example, nuclear magnetic resonance spectroscopy calculated from an integration ratio of 1H attributed to an amide group in the vicinity of 9 to 11 ppm and 1H attributed to an aromatic ring in the vicinity of 6 to 9 ppm. Various methods such as the NMR method, the Fourier transform infrared spectroscopy (FT-IR method), the method for quantifying moisture accompanying imide ring closure, and the carboxylic acid neutralization titration method are used. -Lier transformation infrared spectroscopy (FT-IR method) is the most common method.

In the Fourier transform infrared spectroscopy (FT-IR method), the imidization rate is defined as follows, for example.
That is, assuming that (A) is the number of moles of imide groups at the firing stage (imidation treatment stage) and (B) is the number of moles of imide groups when 100% imidized (theoretical), Is done.
Imidation ratio = [(A) / (B)] × 100
The number of moles of the imide group in this definition can be determined from the absorbance ratio of the characteristic absorption of the imide group measured by the FT-IR method. For example, as a typical characteristic absorption, the imidization ratio can be evaluated using the following absorbance ratio.
(1) Absorbance ratio between 725 cm ⁻¹ (immobilization vibration band of imide ring C═O group) which is one of characteristic absorptions of imide and benzene ring characteristic absorption of 1,015 cm ⁻¹ (2) Characteristics of imide Absorbance ratio between 1,380 cm ⁻¹ (inflection band of imide ring C—N group) which is one of absorption and characteristic absorption of 1,500 cm ^{−1 of} benzene ring (3) One of characteristic absorption of imide Absorbance ratio between 1,720 cm ⁻¹ (an oscillating band of imide ring C═O group) and 1,500 cm ⁻¹ characteristic absorption of benzene ring (4) 1, which is one of characteristic absorption of imide Absorbance ratio between 720 cm ⁻¹ and amide group characteristic absorption 1,670 cm ⁻¹ (interaction between amide group N—H bending vibration and CN stretching vibration) and amide group over 3000 to 3300 cm ⁻¹ That the multiple absorption band of the origin has disappeared Reliability of addition imidization completed if certification is enhanced.

Next, polyamideimide will be described.
<Polyamideimide>
Polyamideimide is a resin having a rigid imide group and an amide group imparting flexibility in the molecular skeleton, and the polyamideimide used in the present invention may have a generally known structure. it can.
Generally, as a method for synthesizing a polyamideimide resin, an acid chloride method (a): a derivative halide of a trivalent carboxylic acid having an acid anhydride group, most typically a chloride compound of the derivative and a diamine are used as solvents. There is known a known method for producing it by reacting in the method (for example, see Japanese Examined Patent Publication No. 42-15637). Alternatively, as another method, an isocyanate method (b): a known method for producing a trivalent derivative containing an acid anhydride group and a carboxylic acid and an aromatic isocyanate in a solvent (for example, Japanese Patent Publication No. 44-19274). No.) are known, and any of them can be used. Each manufacturing method will be described below.

(A) Acid chloride method As a derivative halide compound of a trivalent carboxylic acid having an acid anhydride group, for example, compounds represented by the following formulas (2) and (3) can be used.

  (In the formula, X represents a halogen element.)

(Wherein X represents a halogen element and Y represents —CH ₂ —, —CO—, —SO ₂ — or —O—)

  In each of the above formulas, the halogen element is preferably chloride, and specific examples of derivatives include terephthalic acid, isophthalic acid, 4, 4 ′ biphenyl dicarboxylic acid, 4, 4 ′ biphenyl ether dicarboxylic acid, 4, 4 ′ biphenyl sulfone dicarboxylic acid. Acid, 4, 4 'benzophenone dicarboxylic acid, pyromellitic acid, trimellitic acid, 3, 3', 4, 4 'benzophenone tetracarboxylic acid, 3, 3,' 4, 4 'biphenylsulfone tetracarboxylic acid, 3, Polyvalent carboxylic acids such as 3 ′, 4 and 4 ′ biphenyltetracarboxylic acid, adipic acid, sebacic acid, maleic acid, fumaric acid, dimer acid, stilbene dicarboxylic acid, 1,4 cyclohexanedicarboxylic acid, and 1,2 cyclohexanedicarboxylic acid Of acid chloride.

On the other hand, the diamine is not particularly limited, and any of aromatic diamine, aliphatic diamine, and alicyclic diamine can be used, and aromatic diamine is preferably used.
Aromatic diamines include m-phenylenediamine, p-phenylenediamine, oxydianiline, methylenediamine, hexafluoroisopropylidenediamine, diamino-m-xylylene, diamino-p-xylylene, 1,4-naphthalenediamine, 1, 5-naphthalenediamine, 2,6-naphthalenediamine, 2,7-naphthalenediamine, 2,2′-bis- (4-aminophenyl) propane, 2,2′-bis- (4-aminophenyl) hexafluoro Propane, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl ether, 3,4-diaminobiphenyl, 4,4'-diaminobenzophenone 3,4-diaminodiphenyl ether, iso Propylidenedianiline, 3,3′-diaminobenzophenone, o-tolidine, 2,4-tolylenediamine, 1,3-bis- (3-aminophenoxy) benzene, 1,4-bis- (4-aminophenoxy) ) Benzene, 1,3-bis- (4-aminophenoxy) benzene, 2,2-bis- [4- (4-aminophenoxy) phenyl] propane, bis- [4- (4-aminophenoxy) phenyl] sulfone Bis- [4- (3-aminophenoxy) phenyl] sulfone, 4,4′-bis- (4-aminophenoxy) biphenyl, 2,2′-bis- [4- (4-aminophenoxy) phenyl] Examples include xafluoropropane, 4,4′-diaminodiphenyl sulfide, and 3,3′-diaminodiphenyl sulfide.

  Also, siloxane compounds having amino groups at both ends as diamines, such as 1,3-bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane, α, ω-bis (3-amino Propyl) polydimethylsiloxane, 1,3-bis (3-aminophenoxymethyl) -1,1,3,3-tetramethyldisiloxane, α, ω-bis (3-aminophenoxymethyl) polydimethylsiloxane, 1, 3, -bis (2- (3-aminophenoxy) ethyl) -1,1,3,3-tetramethyldisiloxane, α, ω-bis (2- (3-aminophenoxy) ethyl) polydimethylsiloxane, , 3-bis (3- (3-aminophenoxy) propyl) -1,1,3,3-tetramethyldisiloxane, α, ω-bis (3- (3-aminophenoxy) propi E) If polydimethylsiloxane or the like is used, a silicone-modified polyamideimide can be obtained.

  In order to obtain the polyamideimide (polyamideimide resin) in the present invention by the acid chloride method, the above-described trivalent carboxylic acid derivative halide and diamine having an acid anhydride group are used in the same manner as in the production of the polyimide resin. After dissolving in an organic polar solvent, it is reacted at a low temperature (0 to 30 ° C.) to obtain a polyamideimide precursor (polyamide-amic acid).

  The organic polar solvent that can be used is the same as that of the polyimide, and a formamide solvent (for example, a sulfoxide solvent such as dimethyl sulfoxide and diethyl sulfoxide, N, N-dimethylformamide, N, N-diethylformamide, etc.), Acetamide solvents (eg, N, N-dimethylacetamide, N, N-diethylacetamide, etc.), pyrrolidone solvents (eg, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, etc.), phenol solvents ( For example, phenol, o-, m-, or p-cresol, xylenol, halogenated phenol, catechol, etc.), ether solvent (eg, tetrahydrofuran, dioxane, dioxolane, etc.), alcohol solvent (eg, methanol, ethanol, butanol) etc , Cellosolve type solvents (e.g., butyl cellosolve, etc.), or hexamethylphosphoramide, γ- butyrolactone. These are preferably used alone or as a mixed solvent, and are not particularly limited as long as they dissolve polyamic acid. Particularly preferably used solvents are N, N-dimethylacetamide and N-methyl-2-pyrrolidone.

The polyamide / polyamic acid solution obtained above is mixed with the inorganic filler and the siloxane compound (polydimethylsiloxane or alkylene oxide-modified polymethylsiloxane) of the present invention to prepare a coating solution. After the coating liquid is applied to the support (molding die), the polyamic acid is converted to polyimide (imidation) by treatment such as heating.
Examples of the imidization method include a method of dehydrating and ring-closing by heat treatment, and a method of chemically ring-closing using a dehydrating and ring-closing catalyst. When dehydrating and ring-closing by heat treatment, for example, the reaction temperature is 150 to 400 ° C., preferably 180 to 350 ° C., and the heat treatment time is 30 seconds to 10 hours, preferably 5 minutes to 5 hours. When a dehydration ring closure catalyst is used, the reaction temperature is 0 to 180 ° C., preferably 10 to 80 ° C., and the reaction time is several tens of minutes to several days, preferably 2 to 12 hours. Examples of the dehydration ring closure catalyst include acid anhydrides such as acetic acid, propionic acid, butyric acid, and benzoic acid.

(B) Isocyanate method As the derivative of the trivalent carboxylic acid having an acid anhydride group used in the isocyanate method, for example, a compound represented by the formula (4) or the formula (5) can be used.

  (In the formula, R represents hydrogen, an alkyl group having 1 to 10 carbon atoms, or a phenyl group.)

(In the formula, R represents hydrogen, an alkyl group having 1 to 10 carbon atoms, or a phenyl group, and Y represents —CH ₂ —, —CO—, —SO ₂ —, or —O—).

  Any derivative having the above general formula can be used, but the most typical example is trimellitic anhydride. These trivalent carboxylic acid derivatives having an acid anhydride group can be used alone or in combination depending on the purpose.

Next, as one aromatic polyisocyanate used for the synthesis of the polyamideimide of the present invention, for example, 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, 4,4′-diphenyl ether diisocyanate, 4, 4 '-[2,2-bis (4-phenoxyphenyl) propane] diisocyanate, biphenyl-4,4'-diisocyanate, biphenyl-3,3'-diisocyanate, biphenyl-3,4'-diisocyanate, 3,3'-Dimethylbiphenyl-4,4'-diisocyanate,2,2'-dimethylbiphenyl-4,4'-diisocyanate,3,3'-diethylbiphenyl-4,4'-diisocyanate,2,2'-diethylbiphenyl-4 , 4'-Diisocyanate 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, 2,2'-dimethoxybiphenyl-4,4'-diisocyanate, naphthalene-1,5-diisocyanate, naphthalene-2,6-diisocyanate and the like. .
These aromatic polyisocyanates can be used alone or in combination. Hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, transcyclohexane-1,4-diisocyanate, hydrogenated m-xylylene diene as necessary. Aliphatic such as isocyanate and lysine diisocyanate, alicyclic isocyanate and trifunctional or higher polyisocyanate can also be used.

  In the solution containing the polyamideimide precursor obtained by dissolving the trivalent carboxylic acid derivative having each acid anhydride group and an aromatic polyisocyanate in an organic polar solvent, the inorganic filler, and the present invention. The coating solution is prepared by mixing with the unsaturated carboxylic acid polymer. After the coating liquid is applied to the support, the polyamideimide precursor is converted to polyamideimide by heat treatment. Upon conversion to polyamideimide by this method, polyamideimide is generated without generating a carbonic acid (generally generating carbon dioxide). The following formula (6) shows an example of polyamide imidization when trimellitic anhydride and aromatic isocyanate are used.

  (In the formula, Ar represents an aromatic group.)

The polyimide and polyamideimide shown above are usually used alone, but those selected in consideration of compatibility can also be used in combination.
Moreover, the copolymer which has a polyimide repeating unit and a polyamideimide repeating unit may be sufficient.

Next, a method for producing a seamless belt using the coating liquid containing the polyimide precursor or the polyamideimide precursor will be described.
That is, in the present invention, an inorganic filler, a polyimide precursor or polyamideimide precursor, N-methylpyrrolidone, a polydimethylsiloxane having a kinematic viscosity at 25 ° C. of 1 cSt or more and 20 cSt or less, or 30 cSt or more and 100 cSt or less. In the case where a seamless belt is produced using a coating solution containing an alkylene oxide-modified polymethylsiloxane, it can be achieved by roughly including the following steps. That is, a step (1) of applying and casting the coating liquid on a support (molding mold), a step of removing the solvent in the coating film applied and cast on the support by heating (2), It can be manufactured by the step (3) for promoting imidation of the precursor contained in the coating film by heating at elevated temperature, and the step (4) for releasing the formed thin film from the support to form a seamless belt. .
Depending on the process

First, a case where centrifugal molding is used as a support (molding mold) will be described as an example. The following description is an example and the conditions are not limited thereto.
Centrifugal molding is composed of a cylindrical rotating body. While this cylindrical rotating body is slowly rotated, coating and casting (coating film coating) is performed so that the coating liquid is uniform over the entire inner surface of the cylinder. Form. Thereafter, the rotation speed is increased to a predetermined speed, and when the predetermined speed is reached, the rotation speed is maintained at a constant speed and the rotation is continued for a desired time. And the solvent in a coating film is evaporated at the temperature of about 80-150 degreeC, heating up gradually while rotating. In this process, it is preferable to efficiently circulate and remove atmospheric vapor (such as a volatilized solvent). When a self-supporting film is obtained, it is returned to room temperature, transferred to a heating furnace (firing furnace) capable of high-temperature treatment, heated in steps, and finally heated at about 250 ° C. to 450 ° C. ( Calcination) and sufficiently imidization or polyamide-imidization of the polyimide precursor or polyamide-imide precursor. After completion of imidization or the like, the film is slowly cooled to peel the thin film from the mold. A seamless belt is thus formed. In addition, it is preferable to previously form a mold release agent or a mold release layer on the mold so that the mold can be easily peeled off.

Next, the seamless belt used in the belt constituting unit equipped in the electrophotographic apparatus according to the present invention will be described in detail below with reference to a schematic diagram of relevant parts. The schematic diagram is an example, and the present invention is not limited to this.
The schematic diagram of FIG. 1 shows a schematic configuration of the main part of an electrophotographic apparatus equipped with a belt component and the like.
An intermediate transfer unit 500 that is a belt component shown in FIG. 1 includes an intermediate transfer belt 501 that is an intermediate transfer member stretched around a plurality of rollers. Around the intermediate transfer belt 501, a secondary transfer bias roller 605 that is a secondary transfer charge applying unit of the secondary transfer unit 600, a belt cleaning blade 504 that is an intermediate transfer member cleaning unit, and a lubricant for a lubricant application unit. A lubricant application brush 505 or the like that is an application member is disposed so as to face each other.

  A position detection mark (not shown) is provided on the outer peripheral surface or the inner peripheral surface of the intermediate transfer belt 501. However, on the outer peripheral surface side of the intermediate transfer belt 501, it is necessary to devise a position detection mark that avoids the passing area of the belt cleaning blade 504, which may be difficult to arrange. A position detection mark may be provided on the inner peripheral surface side of the intermediate transfer belt 501. An optical sensor 514 serving as a mark detection sensor is provided at a position between the primary transfer bias roller 507 and the belt driving roller 508 where the intermediate transfer belt 501 is bridged.

  The intermediate transfer belt 501 includes a primary transfer bias roller 507 serving as a primary transfer charge applying unit, a belt driving roller 508, a belt tension roller 509, a secondary transfer counter roller 510, a cleaning counter roller 511, and a feedback current detection roller 512. It is stretched around. Each roller is formed of a conductive material, and each roller other than the primary transfer bias roller 507 is grounded. The primary transfer bias roller 507 is applied with a transfer bias controlled to a predetermined current or voltage according to the number of superimposed toner images by a primary transfer power source 801 controlled at a constant current or voltage. ing.

The intermediate transfer belt 501 is driven in the arrow direction by a belt driving roller 508 that is driven to rotate in the arrow direction by a drive motor (not shown).
The intermediate transfer belt 501 as a belt component is usually a semiconductor or an insulator and has a single-layer or multi-layer structure, but the seamless belt of the present invention is preferably used, thereby improving durability. Excellent image formation can be realized. Further, the intermediate transfer belt is set to be larger than the maximum sheet passing size in order to superimpose the toner images formed on the photosensitive drum 200.

  A secondary transfer bias roller 605 serving as a secondary transfer unit is attached to and separated from a belt outer peripheral surface of the intermediate transfer belt 501 in a portion stretched around the secondary transfer counter roller 510 by a contact / separation mechanism as described later. It is configured to be able to contact and separate. The secondary transfer bias roller 605 is disposed so as to sandwich the transfer paper P, which is a recording medium, between the portion of the intermediate transfer belt 501 stretched around the secondary transfer counter roller 510 and a constant current. A transfer bias having a predetermined current is applied by a secondary transfer power source 802 to be controlled.

  The registration roller 610 feeds the transfer sheet P, which is a transfer material, between the secondary transfer bias roller 605 and the intermediate transfer belt 501 stretched around the secondary transfer counter roller 510 at a predetermined timing. The secondary transfer bias roller 605 is in contact with a cleaning blade 608 as a cleaning unit. The cleaning blade 608 is for removing the adhering matter adhering to the surface of the secondary transfer bias roller 605 for cleaning.

  In the color copying machine having such a configuration, when an image forming cycle is started, the photosensitive drum 200 is rotated in a counterclockwise direction indicated by an arrow by a drive motor (not shown), and Bk ( Black) toner image formation, C (cyan) toner image formation, M (magenta) toner image formation, and Y (yellow) toner image formation are performed. The intermediate transfer belt 501 is rotated clockwise by the belt driving roller 508 as indicated by an arrow. As the intermediate transfer belt 501 rotates, the primary transfer of the Bk toner image, the C toner image, the M toner image, and the Y toner image is performed by the transfer bias by the voltage applied to the primary transfer bias roller 507. Finally, the respective toner images are formed on the intermediate transfer belt 501 in the order of Bk, C, M, and Y.

For example, the Bk toner image formation is performed as follows.
In FIG. 1, a charging charger 203 uniformly charges the surface of the photosensitive drum 200 to a predetermined potential with a negative charge by corona discharge. The timing is determined based on the belt mark detection signal, and raster exposure with laser light is performed based on the Bk color image signal by a writing optical unit (not shown). When this raster image is exposed, the charge proportional to the exposure light amount disappears in the exposed portion of the surface of the photosensitive drum 200 that is initially uniformly charged, and a Bk electrostatic latent image is formed. When the negatively charged Bk toner on the developing roller of the Bk developing device 231K comes into contact with this Bk electrostatic latent image, the toner does not adhere to the remaining portion of the photosensitive drum 200, and the charge is not charged. The toner is attracted to the nonexposed portion, that is, the exposed portion, and a Bk toner image similar to the electrostatic latent image is formed.

  The Bk toner image formed on the photosensitive drum 200 in this manner is primarily transferred onto the belt outer peripheral surface of the intermediate transfer belt 501 that is rotating at a constant speed while being in contact with the photosensitive drum 200. Some untransferred residual toner remaining on the surface of the photoreceptor drum 200 after the primary transfer is cleaned by the photoreceptor cleaning device 201 in preparation for reuse of the photoreceptor drum 200. On the photosensitive drum 200 side, the process proceeds to the Y image forming process after the Bk image forming process, and reading of the Y image data by the color scanner starts at a predetermined timing, and the photosensitive drum is written by laser beam writing with the Y image data. A Y electrostatic latent image is formed on the surface of 200.

  Then, after the rear end portion of the previous Bk electrostatic latent image passes and before the front end portion of the T electrostatic latent image reaches, the revolver developing unit 230 is rotated, and the Y developing device 231Y develops. The Y electrostatic latent image is developed with Y toner. Thereafter, the development of the Y electrostatic latent image area is continued. When the trailing edge of the Y electrostatic latent image passes, the revolver developing unit is rotated in the same manner as in the case of the previous Bk developing machine 231K, and the next The C developing machine 231C is moved to the developing position. This is also completed before the leading edge of the next C electrostatic latent image reaches the developing position. Note that the C and M image forming steps are the same as the Bk and Y steps described above because the color image data reading, electrostatic latent image forming, and developing operations are the same as those described above.

The Bk, Y, C, and M toner images sequentially formed on the photosensitive drum 200 in this way are sequentially aligned on the same surface on the intermediate transfer belt 501 and primarily transferred. As a result, a toner image having a maximum of four colors superimposed on the intermediate transfer belt 501 is formed. On the other hand, at the time when the image forming operation is started, the transfer paper P is fed from a paper feed unit such as a transfer paper cassette or a manual feed tray, and is waiting at the nip of the registration roller 610.
When the leading edge of the toner image on the intermediate transfer belt 501 reaches the secondary transfer portion where the nip is formed by the intermediate transfer belt 501 stretched around the secondary transfer counter roller 510 and the secondary transfer bias roller 605. Then, the registration roller 610 is driven so that the leading edge of the transfer paper P coincides with the leading edge of the toner image, and the transfer paper P is conveyed along the transfer paper guide plate 601, and the transfer paper P and the toner image are transferred. Resist alignment is performed.

  In this way, when the transfer paper P passes through the secondary transfer portion, the four-color superimposed toner image on the intermediate transfer belt 501 is transferred by the transfer bias applied by the secondary transfer power source 802 to the secondary transfer bias roller 605. Are collectively transferred (secondary transfer) onto the transfer paper P. After the transfer paper P is conveyed along the transfer paper guide plate 601 and passed through a portion facing the transfer paper neutralization charger 606 composed of a static elimination needle disposed on the downstream side of the secondary transfer portion, the transfer paper P is discharged. Then, it is sent toward the fixing device 270 by the belt conveying device 210 which is a belt component (see FIG. 1). Then, after the toner image is melted and fixed at the nip portions of the fixing rollers 271 and 272 of the fixing device 270, the transfer paper P is sent out of the apparatus main body by a discharge roller (not shown) and stacked on a copy tray (not shown) face up. Is done. Note that the fixing device 270 may be configured to include a belt component if necessary.

  On the other hand, the surface of the photosensitive drum 200 after the belt transfer is cleaned by the photosensitive member cleaning device 201 and is uniformly discharged by the discharging lamp 202. Further, residual toner remaining on the outer peripheral surface of the intermediate transfer belt 501 after the toner image is secondarily transferred to the transfer paper P is cleaned by the belt cleaning blade 504. The belt cleaning blade 504 is configured to be brought into contact with and separated from the belt outer peripheral surface of the intermediate transfer belt 501 at a predetermined timing by a cleaning member separating and contacting mechanism (not shown).

  A toner seal member 503 that contacts and separates from the belt outer peripheral surface of the intermediate transfer belt 501 is provided on the upstream side of the belt cleaning blade 504 in the movement direction of the intermediate transfer belt 501. The toner seal member 503 receives the falling toner dropped from the belt cleaning blade 504 when cleaning the residual toner, and prevents the falling toner from scattering on the transfer path of the transfer paper P. The toner seal member 503 is brought into contact with and separated from the belt outer peripheral surface of the intermediate transfer belt 501 together with the belt cleaning blade 504 by the cleaning member separating and contacting mechanism.

  The lubricant 506 scraped by the lubricant application brush 505 is applied to the outer peripheral surface of the intermediate transfer belt 501 from which the residual toner has been removed in this way. The lubricant 506 is made of, for example, a solid body such as zinc stearate, and is disposed so as to come into contact with the lubricant application brush 505. Further, residual charges remaining on the outer peripheral surface of the intermediate transfer belt 501 are removed by a neutralizing bias applied by a belt neutralizing brush (not shown) that is in contact with the outer peripheral surface of the intermediate transfer belt 501. Here, the lubricant application brush 505 and the belt neutralizing brush are brought into contact with and separated from the belt outer peripheral surface of the intermediate transfer belt 501 at a predetermined timing by respective contact and separation mechanisms (not shown). .

  Here, at the time of repeat copy, the operation of the color scanner and the image formation on the photosensitive drum 200 are performed at a predetermined timing following the first color (M) image formation process of the first sheet and the first color of the second sheet. The process proceeds to the image forming process (Bk). Further, the intermediate transfer belt 501 has a second Bk toner in the area cleaned by the belt cleaning blade 504 on the outer peripheral surface of the belt following the batch transfer process of the first four-color superimposed toner image to the transfer paper. The image is first transferred. After that, the operation is the same as the first sheet. The above is a copy mode for obtaining a four-color full-color copy. In the three-color copy mode and the two-color copy mode, the same operation as described above is performed for the designated color and the number of times. In the case of the single color copy mode, only the predetermined color developing machine of the revolver developing unit 230 is set in the developing operation state until the predetermined number of sheets is completed, and the belt cleaning blade 504 is kept in contact with the intermediate transfer belt 501. The copy operation is performed in the state.

In the above-described embodiment, the copying machine having only one photosensitive drum 1 has been described. However, the present invention may be configured such that, for example, a plurality of photosensitive drums as shown in FIG. The present invention can also be applied to the image forming apparatus.
FIG. 2 shows a configuration of a four-drum digital color printer including four photosensitive drums 921BK, 921Y, 921M, and 921C for forming toner images of four different colors (black, yellow, magenta, and cyan). An example is shown.

  In FIG. 2, the printer main body 910 includes an image writing unit 912, an image forming unit 913, and a paper feeding unit 914 for performing color image formation by electrophotography. Based on the image signal, the image processing unit performs image processing to convert the signal into black (BK), magenta (M), yellow (Y), and cyan (C) color signals for image formation, and transmits the signals to the image writing unit 912. To do. The image writing unit 912 is a laser scanning optical system including, for example, a laser light source, a deflector such as a rotary polygon mirror, a scanning imaging optical system, and a mirror group. An image writing unit (photosensitive body) 921BK, 921M, 921Y, and 921C that has a writing optical path and is provided for each color of the image forming unit 913 performs image writing corresponding to each color signal.

  The image forming unit 913 includes photoconductors 921BK, 921M, 921Y, and 921C that are image carriers for black (BK), magenta (M), yellow (Y), and cyan (C). As each photoconductor for each color, an OPC photoconductor is usually used. Around each of the photosensitive members 921BK, 921M, 921Y, and 921C, there are a charging device, a laser beam exposure unit from the writing unit 912, and developing devices 920BK, 920M, 920Y, black, magenta, yellow, and cyan. 920C, primary transfer bias rollers 923BK, 923M, 923Y, and 923C as primary transfer units, a cleaning device (not shown), and a photosensitive member discharging device (not shown) are arranged. The developing devices 920BK, 920M, 920Y, and 920C employ a two-component magnetic brush developing system. The intermediate transfer belt 922, which is a belt component, is interposed between the photosensitive members 921BK, 921M, 921Y, and 921C and the primary transfer bias rollers 923BK, 923M, 923Y, and 923C, and is formed on the photosensitive members. The toner images of each color are sequentially superimposed and transferred.

  On the other hand, the transfer paper P is fed from the paper feed unit 914 and then is carried by the transfer conveyance belt 950 which is a belt component through the registration roller 916. When the intermediate transfer belt 922 and the transfer conveyance belt 950 come into contact, the toner image transferred onto the intermediate transfer belt 922 is subjected to secondary transfer (collective transfer) by a secondary transfer bias roller 960 as a secondary transfer unit. ) As a result, a color image is formed on the transfer paper P. The transfer paper P on which the color image is formed is conveyed to the fixing device 915 by the transfer conveying belt 950, and after the image transferred by the fixing device 915 is fixed, it is discharged out of the printer main body.

  The residual toner that is not transferred during the secondary transfer and remains on the intermediate transfer belt 922 is removed from the intermediate transfer belt 922 by the belt cleaning device 925. A lubricant application device (not shown) is disposed on the downstream side of the belt cleaning device 925. This lubricant application device includes a solid lubricant and a conductive brush that rubs against the intermediate transfer belt 922 to apply the solid lubricant. The conductive brush is always in contact with the intermediate transfer belt 922 and applies a solid lubricant to the intermediate transfer belt 922. The solid lubricant has an effect of improving the cleaning property of the intermediate transfer belt 922, preventing the occurrence of filming and improving the durability.

  The seamless belt according to the present invention can be suitably applied to an intermediate transfer belt type image forming apparatus equipped with the intermediate transfer belt 501 or 922 as described above, and a transfer conveyance belt instead of the intermediate transfer belt 501 or 922. The present invention can also be applied to a transfer / conveying belt type image forming apparatus equipped with the above. Further, in the case of an image forming apparatus using a transfer / conveying belt system, the present invention can be applied to either the 1-photosensitive drum system or the 4-photosensitive drum system.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by these examples, and these examples are appropriately modified without departing from the gist of the present invention. Is also within the scope of the present invention (Example 1).
[Preparation of coating solution]
First, each equimolar amount of biphenyl-3,4,3 ′, 4′-tetracarboxylic anhydride and 4,4′-diaminodiphenyl ether was polymerized at room temperature in an N-methylpyrrolidone solvent to obtain a solid content of 17 wt. % Polyamic acid solution was obtained.
Next, N-methylpyrrolidone was charged with carbon black (BP-L manufactured by Cabot) and polysiloxane-containing unsaturated polycarboxylic acid polyester (BYK220S; manufactured by BYK Chemie), and a finely pulverized dispersion was prepared using a bead mill. In the above, the amount of unsaturated polycarboxylic acid polyester added was 0.1 wt% of carbon black.
Using this dispersion and the polyamic acid solution, the carbon content was adjusted to 22 wt% of the polyamic acid solid content, and well stirred and mixed to prepare a coating solution.
[Production of seamless belt]
Next, a metal cylinder having an inner diameter of 100 mm and a length of 300 mm having a mirror-finished inner surface is used as a mold, and the coating liquid is uniformly cast on the inner surface of the cylinder while rotating the cylinder at 50 rpm (times / minute). And then applied as if to flow. When the predetermined amount was completely poured and the coating film was evenly spread, the number of revolutions was increased to 100 rpm, the hot air circulating dryer was introduced, and the temperature was gradually raised to 120 ° C. and heated for 30 minutes. Thereafter, the rotation was stopped, the mixture was put into a heating furnace (baking furnace) capable of high temperature treatment, heated to 350 ° C., and subjected to heat treatment (baking) for 30 minutes.
After stopping the heating by treating for a predetermined time, the mold was taken out after gradually cooling to room temperature, and the formed coating film was peeled off from the inner surface of the cylinder to obtain a seamless belt having a film thickness of 90 μm.
[Internal property evaluation of seamless belt]
The surface state of the inner surface of the manufactured seamless belt was observed with a microscope (VH-8000 manufactured by Keyence).
[Evaluation of uniformity of surface resistance]
The surface resistance values of the inner and outer surfaces of the seamless belt were measured at 10 points each and evaluated by the difference in logarithm between the maximum value and the minimum value. If the difference is 0.5 or less, it can be said that it is good.
The surface resistance value was Hiresta (manufactured by Mitsubishi Chemical), and the value 10 seconds after applying a voltage of 500 V was defined as the surface resistance value.

(Example 2)
The same procedure as in Example 1 was conducted except that the polysiloxane-containing unsaturated polycarboxylic acid polyester (BYK220S; manufactured by BYK Chemie) in Example 1 was replaced with an unsaturated carboxylic acid polymer acid anhydride (BYK-P104; manufactured by BYK Chemie).

(Example 3)
The same as Example 1, except that the polysiloxane-containing unsaturated polycarboxylic acid polyester (BYK220S; manufactured by BYK Chemie) in Example 1 was replaced with the polysiloxane-containing unsaturated carboxylic acid polymer acid anhydride (BYK-P104S; manufactured by BYK Chemie). did.

(Examples 4 to 6)
Example 3 was the same as Example 3 except that the amount of polysiloxane-containing unsaturated carboxylic acid polymer anhydride added was 0.05, 0.5, and 1 wt%.

(Comparative Examples 1-2)
Example 1 was the same as Example 1 except that the addition amount of the unsaturated polycarboxylic acid polyester added to the coating solution in Example 1 was 0 and 2 wt%.

(Example 7)
[Preparation of coating solution]
First, an equimolar amount of trimellitic anhydride and 4,4′-diphenylmethane diisocyanate was polymerized at 150 ° C. in an N-methylpyrrolidone solvent to obtain a polyamideimide solution having a solid content of 15 wt%. To this solution, the carbon dispersion prepared in Example 1 was prepared such that the carbon content was 24 wt% of the solid content of the polyamideimide, and well stirred and mixed to prepare a coating solution.
[Production of seamless belt]
Next, as in Example 1, a metal cylinder having an inner diameter of 100 mm and a length of 300 mm having a mirror-finished inner surface was used as a mold, and the coating liquid was formed into a cylinder while rotating the cylinder at 50 rpm (times / minute). It flowed and applied so that it might be uniformly cast on the inner surface. When the predetermined amount was completely poured and the coating film was evenly spread, the number of revolutions was increased to 100 rpm, the hot air circulating dryer was introduced, and the temperature was gradually raised to 120 ° C. and heated for 30 minutes. Thereafter, the rotation was stopped, the mixture was put into a heating furnace (baking furnace) capable of high temperature treatment, heated to 250 ° C., and subjected to heat treatment (baking) for 30 minutes.
After stopping the heating by treating for a predetermined time, the mold was taken out after gradually cooling to room temperature, and the formed coating film was peeled off from the inner surface of the cylinder to obtain a seamless belt having a film thickness of 85 μm.

(Comparative Example 3)
Example 7 was the same as Example 7 except that the unsaturated polycarboxylic acid polyester added to the coating solution in Example 7 was not added.

  The results are shown in Table 1.

  From the above results, by adopting the constitution of the present invention, a belt having good properties can be obtained, and a durable, high-quality, highly stable seamless belt can be provided even when used for an electrophotographic member.

It is a principal part schematic diagram for demonstrating the seamless belt and apparatus used for the belt structure part of the electrophotographic apparatus which concerns on this invention. FIG. 3 is a schematic diagram illustrating a main part of a configuration example in which a plurality of photosensitive drums are arranged in parallel along one intermediate transfer belt provided in a belt configuration unit of the electrophotographic apparatus according to the present invention.

Explanation of symbols

P transfer paper 200 photoconductor drum 201 photoconductor cleaning device 202 static elimination lamp 203 charging charger 210 belt conveying device 230 revolver developing unit 231Y Y developing machine 231K Bk developing machine 231C C developing machine 231M M developing machine 270 fixing device 271, 272 fixing roller 500 Intermediate transfer unit 501 Intermediate transfer belt 503 Toner seal member 504 Belt cleaning blade 505 Lubricant application brush 507 Primary transfer bias roller 508 Belt drive roller 509 Belt tension controller 510 Secondary transfer counter roller 600 Secondary transfer unit 605 Secondary transfer Bias roller 606 Transfer paper static elimination charger 608 Cleaning blade 610 Registration roller 802 Secondary transfer power source 910 Printer main body 91 2 Image writing unit 913 Image forming unit 914 Paper feeding unit 915 Fixing device 916 Registration roller 920BK, 920M, 920Y, 920C Developing device 921BK, 921M, 921Y, 921C Photoconductor 922 Intermediate transfer belt 923BK, 923M, 923Y, 923C Primary Transfer bias roller 925 Belt cleaning device 950 Transfer conveyance belt 960 Secondary transfer bias roller

Claims (12)

  In a seamless belt formed using a coating solution and containing a filler and polyimide or polyamideimide, the coating solution includes at least a filler, a polyimide precursor or a polyamideimide precursor, and an organic polar solvent. And a seamless belt comprising an unsaturated carboxylic acid polymer.   The seamless belt according to claim 1, wherein the unsaturated carboxylic acid polymer is a carboxylic acid polymer acid anhydride.   The seamless belt according to claim 1, wherein the content of the unsaturated carboxylic acid polymer is 0.05 to 1.0 wt% with respect to the filler.   The seamless belt according to any one of claims 1 to 3, wherein the seamless belt has a film thickness of 50 µm or more.   A seamless belt for a belt component used in an electrophotographic apparatus for transferring a toner developed image formed on an image carrier and forming an image on a recording medium. 4. A seamless belt for a belt component, which is the seamless belt according to any one of 4 above.   An electrophotographic image in which a plurality of color toner development images sequentially formed on an image carrier are sequentially superimposed on an intermediate transfer belt to perform primary transfer, and the resulting primary transfer image is collectively transferred to a recording medium in a secondary transfer. An intermediate transfer belt used in the apparatus, wherein the intermediate transfer belt is constituted by the seamless belt according to claim 1.   A seamless belt manufacturing method comprising manufacturing a seamless belt using a coating liquid containing a filler, a polyimide precursor or a polyamideimide precursor, an organic polar solvent, and an unsaturated carboxylic acid polymer.   A step of applying / casting a coating liquid containing a filler, a polyimide precursor or a polyamideimide precursor, an organic polar solvent, and an unsaturated carboxylic acid polymer to the support; and applying / flowing to the support A step of removing the solvent in the extended coating film by heating, a step of further heating and heating to promote imidation of the precursor contained in the coating film, and releasing the formed coating film from the support And a process for producing a seamless belt comprising a step of making a seamless belt.   The seamless belt according to any one of claims 1 to 4, wherein the belt is an electrophotographic apparatus having a belt constituent part that transfers a toner developed image formed on an image carrier and forms an image on a recording medium. An electrophotographic apparatus, characterized in that   An intermediate transfer belt for performing primary transfer by sequentially superimposing a plurality of color toner developed images sequentially formed on an image carrier on an intermediate transfer belt, and performing secondary transfer of the primary transfer image collectively to a recording medium. The electrophotographic apparatus according to claim 1, wherein the intermediate transfer belt is an intermediate transfer belt constituted by the seamless belt according to any one of claims 1 to 4.   In a coating liquid for seamless belt production comprising a filler and polyimide or polyamideimide, the coating liquid comprises a filler, a polyimide precursor or a polyamideimide precursor, an organic polar solvent, and an unsaturated carboxylic acid polymer. And a coating solution for producing a seamless belt.   The coating solution for seamless belt production according to claim 11, wherein the unsaturated carboxylic acid polymer is a carboxylic acid polymer acid anhydride.

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