JP2008292616A - Electrophotographic seamless belt, method for manufacturing the same and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a clean electrophotographic seamless belt having excellent mechanical durability and no residual solvent, and a manufacturing method for obtaining the seamless belt with high manufacturing efficiency. <P>SOLUTION: The electrophotographic seamless belt is obtained by forming a film by applying and drying a coating liquid comprising a solution of a polyimide or polyamide-imide precursor in an organic polar solvent or a solvent-soluble polyimide solution, wherein the seamless belt is treated by contact with at least either supercritical carbon dioxide or subcritical carbon dioxide and has a residual solvent content of <0.1 wt.%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

In electrophotographic apparatuses, seamless belt members are used for various purposes in the apparatus. For example, a fixing belt, a transfer belt, a paper conveyance belt, and the like can be given.
Among them, in recent years, particularly in a full-color electrophotographic apparatus, a full-color image is formed on an intermediate transfer belt by once transferring the four-color toner images formed on the photosensitive member to the intermediate transfer belt, and then a paper or the like There is an intermediate transfer belt in a system for batch transfer to a transfer medium.

Further, in this method, in order to obtain high speed, a method called a tandem method in which color developing devices for respective colors facing the intermediate transfer belt are arranged in series is the mainstream. The intermediate transfer belt used in this process is required to have a high strength that can withstand repeated use without causing color overlap due to deformation during running.
Moreover, since a flame retardance is also requested | required, a polyimide and a polyamide-imide resin are used preferably.

In the intermediate transfer belt made of polyimide resin, in order to obtain the required mechanical strength, a device in the manufacturing method has been proposed, and we have already proposed some devices (for example, see Patent Documents 1 to 3).
As the organic solvent used for the polyimide resin, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like are generally used. Of these, N-methylpyrrolidone is most often used.
However, N-methylpyrrolidone is said to have a reproductive toxicity function, and it is not preferable that the N-methylpyrrolidone itself remains in the product in a large amount.

In Patent Document 4, after the coating film is dried for a long time at a low temperature of 100 to 200 ° C. to sufficiently evaporate and remove the solvent, it is heated at a high temperature of 300 ° C. or higher to be converted into a polyimide, whereby the residual solvent amount is 1 ppm. An intermediate transfer belt made of the following polyimide resin has been proposed. This describes the effect of preventing white spots in the image. However, since the intermediate transfer belt manufactured under the conditions for minimizing the residual solvent is inferior in flexibility, it is inferior in durability due to continuous repeated use in the apparatus, and cracks and cracks occur.
In Patent Documents 5 to 8, it is proposed to improve flexibility by allowing the residual solvent amount to remain to a specified value. For example, in Patent Document 7, the polyimide precursor on the side in contact with the mold is at a higher temperature. It is described that it is easy to be polyimideized and therefore the solvent is easily contained inside, but the solvent is easily evaporated from the opposite side of the polyimide precursor surface, so that the opposite side of the polyimide precursor surface is additionally heated. This is not preferable because of the large amount of residual solvent for the reasons described above.
In Patent Document 9, it is proposed that the flexibility is improved by drying at a low temperature in order to obtain a certain amount of residual solvent in the production process and then heating at a high temperature to contain the residual solvent in the formed polyimide structure. ing. However, those produced by this production method may result in an increase in the final residual solvent amount, which is not preferable.
Thus, since N-methylpyrrolidone has a high boiling point, it tends to remain relatively. Moreover, in order to obtain sufficient mechanical strength, it is said that it is necessary to imidize in a state where a certain amount of N-methylpyrrolidone remains, and there is a high possibility that a certain amount will finally remain.
In order to reduce the residual amount of N-methylpyrrolidone while ensuring the durability of the belt, it takes a very long time for the drying process to increase the production cost.
Patent Document 10 proposes to extract unnecessary low-molecular components from a polyimide film having a structure using supercritical carbon dioxide at a polyamic acid stage before polyimidization, and then heat to polyimidize. Has been. However, in this case, the supercritical carbon dioxide treatment is performed at the polyamic acid stage before polyimidation, and the solubility of the eluate in supercritical carbon dioxide decreases as the temperature of supercritical carbon dioxide treatment increases. It is described ([0029]) that supercritical extraction at a high temperature that accompanies polyimide formation should be avoided, and there is skepticism about the removal of residual solvent by supercritical carbon dioxide treatment after polyimide formation.

JP 2006-259405 A JP 2006-330242 A JP 2006-348094 A Japanese Patent Laid-Open No. 11-24427 JP 2006-53190 A JP 2005-345692 A JP 2001-96550 A JP 2000-313071 A JP 2005-254744 A JP 2002-167434 A

  The present invention solves the above-mentioned problems of the prior art, and provides a clean electrophotographic seamless belt excellent in mechanical durability and free of residual solvent, and a production method for obtaining it with high production efficiency. For the purpose.

  As a result of intensive studies, the present inventors have found that the above-described problem is that at least supercritical carbon dioxide and subcritical carbon dioxide are produced from a seamless belt produced by a method that sufficiently obtains mechanical properties using a polyimide resin or a polyamideimide resin. It has been found that this can be achieved by removing the solvent remaining in the film by performing a treatment for contacting with either of them.

That is, the said subject is solved by the following this invention.
(1) In the seamless belt for electrophotography formed by applying and drying a coating solution comprising at least an organic polar solvent solution of a polyimide precursor or a polyamideimide precursor, or a solvent-soluble polyimide solution, the seamless belt Is subjected to a treatment for contact with at least one of supercritical carbon dioxide or subcritical carbon dioxide, and the residual solvent amount is less than 0.1 wt%,
(2) “Seamless belt for electrophotography according to item (1), wherein the folding resistance of the seamless belt according to the MIT weather resistance test is 1000 times or more”,
(3) "Seamless belt for electrophotography according to item (1) or (2), wherein the seamless belt contains a resistance adjusting agent",
(4) “In a seamless belt for a belt constituting unit provided in an electrophotographic apparatus for transferring a toner developed image formed on an image carrier and forming an image on a recording medium, the belt is the first (1 ) To a belt constituting part according to any one of the items (3) to (3),
(5) “A plurality of color toner developed images sequentially formed on the image carrier are sequentially superimposed on the intermediate transfer belt for primary transfer, and the primary transfer images are collectively transferred to the recording medium. In the seamless belt for a belt constituting part provided in the electrophotographic apparatus, the intermediate transfer belt is the seamless belt according to any one of the items (1) to (3). Seamless belt for components ",
(6) In an electrophotographic apparatus equipped with a belt component, a toner developed image formed on an image carrier is transferred to form an image on a recording medium, and the belt includes the above items (1) to (1). An electrophotographic apparatus characterized by being a seamless belt according to any one of (3) ",
(7) “A plurality of color toner development images sequentially formed on the image carrier are sequentially superimposed on the intermediate transfer belt for primary transfer, and the primary transfer images are collectively transferred to the recording medium. In the electrophotographic apparatus equipped with the belt component, the intermediate transfer belt is the seamless belt according to any one of the items (1) to (3),
(8) “Applying step of applying a coating solution comprising at least an organic polar solvent solution of a polyimide precursor or a polyamideimide precursor or a solvent-soluble polyimide solution on the surface of the mold in a predetermined thickness, and drying the applied mold. A drying process for cooling, a cooling process for cooling the mold after drying, a demolding process for removing the film from the cooled mold, and a process for bringing the seamless belt obtained by demolding into contact with at least one of supercritical carbon dioxide or subcritical carbon dioxide A process for producing a seamless belt for electrophotography characterized by comprising a step ",
(9) “Applying step of applying a coating solution comprising at least a polyimide precursor or a polyamideimide precursor in an organic polar solvent solution or a solvent-soluble polyimide solution on the surface of the mold in a predetermined thickness, and drying the applied mold. A drying process for cooling, a cooling process for cooling the mold after drying, a demolding process for removing the film from the cooled mold, and a process for bringing the seamless belt obtained by demolding into contact with at least one of supercritical carbon dioxide or subcritical carbon dioxide In the process for producing a seamless belt for electrophotography having a process, the seamless belt is produced under the condition that the residual solvent amount of the solvent in the demolding process is 0.1 to 5 wt%, and 0.1 wt% by the treatment process. A process for producing a seamless belt for electrophotography, characterized by
(10) “At least a step of dispersing a resistance modifier in an organic polar solvent solution of a polyimide precursor or a polyamideimide precursor, or a solvent-soluble polyimide solution, and a coating solution prepared by the step on a mold surface to a predetermined thickness The coating process for coating, the drying process for heating and drying the coated mold, the cooling process for cooling the mold after drying, the demolding process for removing the film from the cooled mold, A method for producing an intermediate transfer belt for electrophotography, comprising a treatment step of contacting with at least one of carbon and subcritical carbon dioxide ",
(11) “A step of dispersing a resistance adjusting agent in an organic polar solvent solution of at least a polyimide precursor or a polyamideimide precursor, or a solvent-soluble polyimide solution, and a coating solution prepared by the step on the surface of the mold with a predetermined thickness The coating process for coating, the drying process for heating and drying the coated mold, the cooling process for cooling the mold after drying, the demolding process for removing the film from the cooled mold, In the method for producing an electrophotographic intermediate transfer belt having a treatment step of contacting with at least one of carbon and subcritical carbon dioxide, the intermediate transfer belt has a residual solvent amount of 0.1 to 5 wt% during the demolding step. The process for producing an intermediate transfer belt for electrophotography, characterized in that the amount is less than 0.1 wt% by the treatment step.
(12) “The method for producing an intermediate transfer belt according to the item (10) or (11), wherein the intermediate transfer belt has a folding resistance of 1000 or more times according to an MIT weather resistance test”. .

According to the first aspect, it is possible to obtain a seamless belt for electrophotography of polyimide or polyamideimide with very little residual solvent.
According to the second aspect of the present invention, it is possible to obtain an electrophotographic seamless belt having flexibility and high mechanical durability.
According to the third aspect, it is possible to obtain an electrophotographic seamless belt in which conductivity is imparted to an arbitrary resistance value.
According to a fourth aspect of the present invention, there is provided a seamless belt for a belt constituting portion provided in an electrophotographic apparatus for transferring a toner developed image formed on an image carrier and forming an image on a recording medium. Obtainable.
According to the fifth aspect of the present invention, a plurality of color toner developed images sequentially formed on the image carrier having the above effects are sequentially superimposed on the intermediate transfer belt to perform primary transfer, and the primary transfer image is recorded. It is possible to obtain an intermediate transfer belt for an electrophotographic apparatus that performs secondary transfer collectively on a medium.
According to the sixth aspect, an electrophotographic apparatus using a seamless belt having the above effects can be obtained.
According to the seventh aspect, it is possible to obtain a full-color electrophotographic apparatus using the intermediate transfer belt having the above effects.
According to the eighth aspect, it is possible to produce a polyimide or polyamide-imide seamless belt for electrophotography with very little residual solvent.
According to the ninth aspect of the present invention, it is possible to produce a polyimide or polyamideimide seamless belt for electrophotography with very little residual solvent with high productivity.
According to the tenth aspect, it is possible to produce a polyimide or polyamide-imide intermediate transfer belt for electrophotography with very little residual solvent.
According to the eleventh aspect, it is possible to produce an electrophotographic intermediate transfer belt of polyimide or polyamideimide with very little residual solvent with high productivity.
According to the twelfth aspect, it is possible to produce a polyimide or polyamide-imide electrophotographic intermediate transfer belt with extremely low residual solvent and excellent mechanical durability with high productivity.

The seamless belt made of polyimide or polyamideimide according to the present invention is obtained by applying a coating solution containing a polyimide precursor or polyamideimide precursor using an organic polar solvent, or a solvent-soluble polyimide to the mold. Molded.
Hereinafter, the coating liquid will be described.

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 first obtained via a polyamic acid (polyimide precursor) by reaction of a generally known aromatic polycarboxylic acid anhydride or derivative thereof with 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 chemical reaction formula.

(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- Phenolic 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 hex Methyl 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 a plurality of diamines are dissolved in the above organic solvent or diffused 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, the polyamic acid composition is dissolved in the organic polar solvent by polymerizing the aromatic polyvalent carboxylic acid anhydride or derivative thereof and the aromatic diamine component in about an equimolar amount of the organic polar solvent. A polyimide precursor solution is obtained in a uniformly 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.
Typical examples include Trenice (manufactured by Toray Industries, Inc.), U-Varnish (manufactured by Ube Industries, Ltd.), Optmer (manufactured by JSR), SE812 (manufactured by Nissan Chemical Industries), CRC8000 (manufactured by Sumitomo Bakelite Co., Ltd.), and the like. It is mentioned as a thing.

  The inorganic filler is mixed and dispersed in the synthesized or obtained polyamic acid solution, and the siloxane compound (polydimethylsiloxane or alkylene oxide-modified polymethylsiloxane) of 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.
However, recently, although it is a kind of the method (2), a method of promoting imidization at the time of drying by incorporating an amine such as imidazole or quinoline in the varnish as a catalyst is often employed. In order to demonstrate the intrinsic performance of polyimide, it is necessary to complete the imidization by heating above the glass transition temperature of the corresponding polyimide, but this promotes imidization at a lower temperature. It is said that mechanical durability is also improved. However, these catalysts are in very small amounts, and some of them decompose and sublime during drying, but some remain as impurities, which is not preferable.

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

In 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), It is.
Imidation rate = [(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 band of imide ring C═O group), which is one of characteristic absorptions of imide, and 1,015 cm ⁻¹ of characteristic absorption of benzene rings.
(2) Absorbance ratio between 1,380 cm ⁻¹ (inflection vibration band of imide ring C—N group), which is one of characteristic absorptions of imide, and 1,500 cm ⁻¹ of characteristic absorption of benzene rings.
(3) Absorbance ratio between 1,720 cm ⁻¹ (immobilization vibration band of imide ring C═O group) which is one of characteristic absorptions of imide and 1,500 cm ⁻¹ of characteristic absorption of benzene ring.
(4) 1,720 cm ⁻¹ which is one of characteristic absorptions of imide and 1,670 cm ⁻¹ (interaction between amide group N—H bending vibration and C—N stretching vibration) Absorbance ratio.
Moreover, if it is confirmed that the multiple absorption band derived from the amide group over 3000 to 3300 cm ⁻¹ disappears, the reliability of imidization completion is further increased.

In the present invention, not only the polyimide precursor solution as described above but also a so-called solvent-soluble polyimide that has been imidized in advance and is soluble in an organic polar solvent can be used.
Examples of such materials include Rika Coat (New Nippon Rika) and block copolymerized polyimide (PI Giken).

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.
In general, as a method for synthesizing a polyamideimide resin, (a) acid chloride method: a derivative halide of a trivalent carboxylic acid having an acid anhydride group, most typically a chloride compound of the derivative and a diamine as a solvent A known method (for example, Japanese Examined Patent Publication No. S42-15637) for producing by reacting in the process is known. Alternatively, as another method, (b) Isocyanate method: 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 general formula (I) and general formula (II) can be used.

（式中、Ｘはハロゲン元素を示す。）

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

（式中、Ｘはハロゲン元素を示し、Ｙは−ＣＨ_２−、−ＣＯ−、−ＳＯ_２−または−Ｏ−を示す。）

(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 treatment (heating, etc.) is performed to convert polyamic acid to polyimide (imidization).

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 a derivative of a trivalent carboxylic acid having an acid anhydride group used in the isocyanate method, for example, a compound represented by the following general formula (III) or the following general formula (IV) may be used. it can.

（式中、Ｒは水素、炭素数１〜１０のアルキル基またはフェニル基を示す。）

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

（式中、Ｒは水素、炭素数１〜１０のアルキル基またはフェニル基を示し、Ｙは−ＣＨ_２−、−ＣＯ−、−ＳＯ_２−または−Ｏ−を示す。）

(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 of the derivatives having the above general formula (III) and general formula (IV) 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 adjusting the derivative of the trivalent carboxylic acid having each acid anhydride group and the aromatic polyisocyanate in an organic polar solvent, the inorganic filler, and the present invention The coating solution is prepared by mixing with the siloxane compound (polydimethylsiloxane or alkylene oxide-modified polymethylsiloxane). 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). An example of polyamide imidation when trimellitic anhydride and aromatic isocyanate are used in the following chemical reaction formula is shown.

（式中、Ａｒは芳香族基を示す。）

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

<Measurement of residual solvent>
The measurement of the residual solvent in the present invention is as follows.
That is, a heat extraction gas chromatogram mass spectrometer was used for quantification of the residual solvent.
The belt was cut to about 2 to 3 mg, weighed accurately, and then placed in a heat extraction device (PY2020D: manufactured by Frontier Laboratories) and heated to 400 ° C. Volatile components were injected into a gas chromatogram mass spectrometer (GCMS-QP2010: manufactured by Shimadzu Corporation) via a 320 ° C. interface and quantified.
More specifically, helium gas is used as a carrier gas, 1/51 (split ratio 50: 1) of the amount volatilized from the sample is linear velocity 153.8 cm / second (carrier gas flow rate 1.50 ml at a column temperature of 50 ° C.) / Min, pressure 50 kPa), and injected into a column (capillary column UA-5 manufactured by Frontier Laboratories Inc.) having an inner diameter of 0.25 μmφ × 30 m. Next, after holding at 50 ° C. for 3 minutes, the column was heated to 400 ° C. at a rate of 8 ° C. per minute and held at that temperature for 10 minutes to desorb volatile components. Furthermore, a volatile component was injected into the mass spectrometer at an interface temperature of 320 ° C., and the peak area corresponding to the solvent was determined.
In quantification, a calibration curve was prepared in advance with a known amount of the same solvent (N-methyl-2-pyrrolidone). (N-methyl-2-pyrrolidone under these conditions corresponds to a peak with a retention time of 9.8 minutes (mass number 99).)

In the coating liquid of this invention, you may contain not only the said polyimide and polyamideimide but another resin component as needed.
Moreover, you may use various additives, such as a leveling agent, a lubricant, antioxidant, a catalyst.

Next, the resistance adjusting agent contained as a component of the coating liquid of the present invention will be described.
When used as a seamless belt in the present invention, particularly as an intermediate transfer belt, it is necessary to adjust to a predetermined resistance value, and the addition of a resistance adjusting agent is indispensable.
As the resistance control agent, 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 (sub) oxide powders such as indium oxide doped with tin. In addition, as an ion conductive resistance control agent, 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. Further, polyether amide, polyether ester amide, polypyrrole, polythiophene, polyaniline, or the like which is a conductive polymer may be used. In addition, the resistance control agent in this invention is not limited to these exemplary compounds.

In the present invention, carbon black is preferably used among the resistance control agents.
Examples of the carbon black include furnace black, acetylene black, ketjen black, channel black, and acetylene black. Oxidized carbon black obtained by oxidizing these surfaces is preferable.
Moreover, you may use a dispersion aid as needed. Furthermore, the surface functional group of carbon black and the surface treatment may be performed by reacting an organic compound having reactivity with the functional group.

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, a step of dispersing a resistance adjusting agent as necessary, a step of applying and casting a coating solution prepared by the step on a support (molding mold), and a coating film applied and cast on the support A step of removing the solvent therein by heating, a step of heating and promoting the imidation of the precursor contained in the coating film, a step of releasing the formed thin film from the support to form a seamless belt, It can be produced by a step of contacting with critical carbon dioxide or subcritical carbon dioxide.

In the step of dispersing the resistance adjusting agent, there are a method of dispersing and mixing the resistance control agent directly in the polyimide precursor solution or a method of dispersing the resistance control agent in a solvent in advance and then mixing with the polyimide precursor solution.
Here, a method of dispersing carbon black as a resistance control agent will be described as an example. Note that this is an example and the present invention is not limited to this.

N-methyl-2-pyrrolidone is mixed with a small amount of carbon black and a polyimide precursor, and dispersed in a ball mill, paint shaker, bead mill or the like for a predetermined time using zirconia beads. After being dispersed to a certain particle size, the liquid taken out is used as a dispersion.
The polyimide precursor solution is mixed with the dispersion to dilute to a predetermined carbon black concentration. As a mixing method at this time, a centrifugal stirrer, a Henschel mixer, a homogenizer, a planetary stirrer, or the like can be used.
If necessary, additives such as a leveling agent and a catalyst can be added at this time.
Further, after stirring, it is preferable to defoam using a vacuum defoamer or the like.

Next, the process of applying the coating solution prepared above will be described.
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 (forming a coating film) is performed so that the coating liquid is uniform throughout. . 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, and subjected to high temperature heat treatment (firing) at about 250 ° C. to 400 ° C. to imidize the polyimide precursor. To do. After completion of imidization and the like, the thin film is peeled off from the mold by slow cooling. A seamless belt is thus formed. In addition, it is preferable to form a mold release agent or a mold release layer on the mold so that it can be easily peeled off.

A process of bringing the seamless belt obtained by demolding after sufficiently cooling into contact with supercritical carbon dioxide will be described.
By placing the seamless belt in the supercritical fluid field, the residual solvent remaining in the seamless belt can be extracted into the supercritical carbon dioxide.
As a supercritical fluid, it exists as a non-condensable high-density fluid in the temperature and pressure range that exceeds the limit (critical point) where gas and liquid can coexist, does not cause condensation even when compressed, and exceeds the critical temperature. As long as the fluid is in a state of a critical pressure or higher, there is no particular limitation, and it can be appropriately selected according to the purpose.However, one having a low critical temperature is preferable, and the subcritical fluid is the critical point. As long as it exists as a high-pressure liquid in the temperature / pressure region in the vicinity, there is no particular limitation and can be appropriately selected according to the purpose. Examples of these fluids include carbon monoxide, carbon dioxide, ammonia, nitrogen, Preferable examples include water, methanol, ethanol, ethane, propane, 2,3-dimethylbutane, benzene, chlorotrifluoromethane, and dimethyl ether. Among these, carbon dioxide is particularly preferable in that the critical temperature is as low as about 31.3 ° C., the influence on polyimide and other additives is small, and the handling is excellent. Use of another liquid having a high critical temperature is not preferable because a part of the polyimide may be decomposed.

As preferable conditions for the supercritical carbon dioxide or subcritical carbon dioxide treatment, the temperature is 35 to 200 ° C, more preferably 40 to 100 ° C. The pressure is 7.1 to 60 MPa. From the viewpoint of belt material and processing efficiency, it is more preferable that the temperature is low and the pressure is high.
In addition to the supercritical carbon dioxide or the subcritical carbon dioxide, another liquid (entrainer) can be used in combination as necessary. As the entrainer, an organic solvent other than the above supercritical fluid may be used. However, in this case, since the liquid used as the entrainer remains on the final belt, it is necessary to remove this, and after the entrainer combined process, there is an extraction process of only supercritical carbon dioxide without using the entrainer. is necessary.
Therefore, it is not necessary to use an entrainer for applications that do not require an extract other than the residual solvent.

The apparatus used for the treatment is not particularly limited and may be appropriately selected according to the purpose. For example, a pressure vessel for performing the treatment shown in FIG. 3 and a pressure pump for supplying supercritical carbon dioxide And a separation tank having a decompression valve that separates the extracted gas containing the performance-decreasing component and the solvent into the extract and the solvent.
As a processing method using the apparatus, first, a seamless belt is charged into the pressure vessel, and the supercritical carbon dioxide is supplied into the pressure vessel by a pressure pump, and the supercritical carbon dioxide is brought into contact with the pressure vessel. A solvent and a performance-decreasing component are extracted, and supercritical carbon dioxide containing the component is discharged. Then, when the supercritical carbon dioxide is returned to room temperature and normal pressure, the supercritical carbon dioxide becomes a gas, so that removal of the solvent becomes unnecessary. At this time, the separation tank may be depressurized by the pressure reducing valve to separate the performance-decreasing component and the supercritical fluid, and the supercritical fluid may be reused.

The belt is prepared so that the residual solvent amount is 0.1 to 5 wt% before the supercritical carbon dioxide treatment, and 0.1 wt% after the supercritical carbon dioxide treatment. % Is preferable. When the residual solvent before the supercritical carbon dioxide treatment is small, although it depends on the drying conditions, if it is produced in a process time considering productivity, the mechanical durability is inferior.
In the present invention, the conditions for the residual solvent amount to be 0.1 to 5 wt% will be described. This is the polyimide raw material used, the initial solvent type and amount used, the addition amount of the resistance regulator, the presence or absence of an imidization catalyst, and the like. However, depending on many requirements, it cannot be generally stated, but depends mainly on the drying conditions and firing conditions of the coating film. In particular, primary drying conditions (as described above, it is preferable to heat and dry at low temperatures for a relatively long time avoiding the polyimide reaction as much as possible), and the rate of temperature increase from primary drying to firing (0.1 ° C. or more per minute) The heating rate is preferred), the firing temperature and the firing time (as described above, preferably 150 to 400 ° C. and 30 seconds to 10 hours) are the largest factors.

In particular, in the intermediate transfer belt containing carbon black, the solvent is more difficult to escape due to the carbon black contained, and more of the solvent tends to remain. Further, when carbon black is contained, it tends to be brittle, so that the mechanical durability is inferior to that when it is not contained.
If there is too much residual solvent in the belt before supercritical carbon dioxide treatment (exceeding 5 wt%), voids are formed in the belt after solvent extraction, it becomes easy to absorb moisture, and dimensional variation due to the humidity environment is undesirable. . Specifically, the belt stretches when the humidity is high, and an abnormal image such as color misregistration occurs due to poor running.
After the treatment with supercritical carbon dioxide, it is preferable that there is no residual solvent as much as possible.

  The mechanical durability is a bending performance, and can be evaluated by the number of bending times until the belt material is broken by an MIT weather resistance test. The measurement method conforms to JIS-P8115. As measurement conditions, a sample having a width of 15 mm is measured under the conditions of a load of 1 kgf, a bending angle of 135 degrees, a bending speed of 175 times / minute, and it is preferable that the measurement is performed 1000 times or more. More preferably, 5000 times or more is good.

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.
The intermediate transfer unit (500) including the belt member 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), there are a secondary transfer bias roller (605) as a secondary transfer charge applying means of the secondary transfer unit (600), and a belt cleaning blade (504) as an intermediate transfer body cleaning means. A lubricant application brush (505), which is a lubricant application member of the lubricant application means, is disposed so as to face each other.

  Also, position detection marks (not shown) are provided on the outer peripheral surface or 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. In this case, a position detection mark may be provided on the inner peripheral surface side of the intermediate transfer belt (501). The 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) on which the intermediate transfer belt (501) is stretched.

  The intermediate transfer belt (501) includes a primary transfer bias roller (507), a belt driving roller (508), a belt tension roller (509), a secondary transfer counter roller (510), which are primary transfer charge applying means, and a cleaning device. It is stretched between the counter roller (511) and the feedback current detection roller (512). Each roller is made of a conductive material, and each roller other than the primary transfer bias roller (507) is grounded. The primary transfer bias roller (507) is controlled by a primary transfer power source (801) controlled by a constant current or a constant voltage so that the current or voltage is controlled to a predetermined magnitude according to the number of superimposed toner images. A bias is applied.

The intermediate transfer belt (501) is driven in the direction of the arrow by a belt drive roller (508) that is driven to rotate in the direction of the arrow by a drive motor (not shown).
The intermediate transfer belt (501) as the belt member is usually a semiconductor or an insulator and has a single-layer or multi-layer structure, but in the present invention, a seamless belt is preferably used, thereby improving durability. In addition, excellent image formation can be realized. In addition, 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), which is a secondary transfer means, is in contact with / separating means, which will be described later, with respect to the belt outer peripheral surface of a portion of the intermediate transfer belt (501) stretched around the secondary transfer counter roller (510). It is comprised so that contact / separation is possible by the contact / separation mechanism. The secondary transfer bias roller (605) sandwiches the transfer paper (P) as a recording medium between the secondary transfer counter roller (510) and the intermediate transfer belt (501) stretched between the secondary transfer counter roller (510). A transfer bias having a predetermined current is applied by a secondary transfer power source (802) that is arranged and controlled at a constant current.

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

  In the color copying machine having such a configuration, when the image forming cycle is started, the photosensitive drum (200) is rotated in a counterclockwise direction indicated by an arrow by a driving motor (not shown), and the photosensitive drum (200) is rotated on the photosensitive drum (200). In addition, 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, 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 charged uniformly, 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 adheres to the portion where the charge of the photosensitive drum (200) remains. In other words, toner is attracted to a portion having no charge, that is, an 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 way is primary on the belt outer peripheral surface of the intermediate transfer belt (501) rotating at a constant speed while being in contact with the photosensitive drum (200). Transcribed. 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). Is done. On the photosensitive drum (200) side, the process proceeds to the Y image forming process after the Bk image forming process, and reading of Y image data by a color scanner starts at a predetermined timing. A Y electrostatic latent image is formed on the surface of the body drum (200).

  Then, after the rear end portion of the previous Bk electrostatic latent image passes and before the front end portion of the Y electrostatic latent image arrives, the revolver developing unit (230) is rotated, and the Y developing machine ( 231Y) is set at the development position, and the Y electrostatic latent image is developed with Y toner. Thereafter, the development of the Y electrostatic latent image area is continued, but when the rear end of the Y electrostatic latent image passes, the revolver developing unit is rotated in the same manner as in the previous Bk developing machine (231K). Then, the next 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 manner 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).
Then, on the intermediate transfer belt (501), the intermediate transfer belt (501) stretched around the secondary transfer counter roller (510) and the secondary transfer bias roller (605) form a nip. When the leading edge of the toner image approaches, 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 is transferred along the transfer paper guide plate (601). The paper (P) is conveyed and registration of the transfer paper (P) and the toner image is performed.

  In this way, when the transfer paper (P) passes through the secondary transfer portion, the intermediate transfer belt (501) is transferred by the transfer bias generated by the voltage applied to the secondary transfer bias roller (605) by the secondary transfer power source (802). ) The four-color superimposed toner image on the top is transferred onto the transfer paper (P) at once (secondary transfer). This transfer paper (P) is conveyed along the transfer paper guide plate (601) and passes through a portion facing the transfer paper neutralization charger (606) comprising a static elimination needle disposed downstream of the secondary transfer portion. After being neutralized by this, the belt is conveyed 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 portion 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). Stacked face up on a copy tray (not shown). 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). The 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 contact and separate at a predetermined timing with respect to the belt outer peripheral surface of the intermediate transfer belt (501) 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 moving direction of the intermediate transfer belt (501). Yes. The toner seal member (503) receives the falling toner dropped from the belt cleaning blade (504) during cleaning of the residual toner, and the falling toner is scattered on the transfer path of the transfer paper (P). It is preventing. 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 belt 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) 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 and out of contact with the outer peripheral surface of the intermediate transfer belt (501) at a predetermined timing by a contact / separation mechanism (not shown). It has become.

  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 image formation process for the fourth color (M) of the first sheet. The process proceeds to the image forming process for the first color (Bk). The intermediate transfer belt (501) has two sheets 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 Bk toner image of the eye is primarily 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 number of times. In the case of the single color copy mode, only the developing device of the predetermined color 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 moved to the intermediate transfer belt (501). The copy operation is performed with the touch panel kept in contact.

In the above embodiment, the copying machine having only one photosensitive drum has been described. However, in the present invention, for example, a plurality of photosensitive drums as shown in FIG. 2 are arranged side by side along one intermediate transfer belt. It can also be applied to an image forming apparatus.
FIG. 2 shows a four-drum type digital color printer having four photosensitive drums (21BK, 21Y, 21M, 21C) for forming toner images of four different colors (black, yellow, magenta, cyan). An example of the configuration is shown.

  In FIG. 2, the printer main body (10) includes an image writing unit (12), an image forming unit (13), and a paper feeding unit (14) for performing color image formation by electrophotography. Based on the image signal, the image processing unit converts the image into black (BK), magenta (M), yellow (Y), and cyan (C) color signals for image formation, and the image writing unit (12). Send to. The image writing unit (12) 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. Image writing corresponding to each color signal is performed on an image carrier (photoreceptor) (21BK, 21M, 21Y, 21C) provided for each color of the image forming unit (13).

  The image forming unit (13) includes photosensitive members (21BK, 21M, 21Y, and 21C) that are image carriers for black (BK), magenta (M), yellow (Y), and cyan (C). I have. As each photoconductor for each color, an OPC photoconductor is usually used. Around each photosensitive member (21BK, 21M, 21Y, 21C), there are a charging device, a laser beam exposure unit from the writing unit (12), and a developing device (20BK) for each color of black, magenta, yellow, and cyan. , 20M, 20Y, 20C), a primary transfer bias roller (23BK, 23M, 23Y, 23C) as a primary transfer unit, a cleaning device (not shown), a photoconductor neutralizing device (not shown), and the like. . The developing device (20BK, 20M, 20Y, 20C) uses a two-component magnetic brush developing system. The intermediate transfer belt (22), which is a belt component, is interposed between each photoconductor (21BK, 21M, 21Y, 21C) and each primary transfer bias roller (23BK, 23M, 23Y, 23C). The toner images of the respective colors formed on the photoconductor are sequentially superimposed and transferred.

  On the other hand, the transfer paper (P) is fed from the paper feeding section (14) and then carried on the transfer conveyance belt (50), which is a belt constituting section, via the registration rollers (16). When the intermediate transfer belt (22) and the transfer conveying belt (50) come into contact with each other, the toner image transferred onto the intermediate transfer belt (22) is transferred to a secondary transfer bias roller (60) as a secondary transfer unit. ) For secondary transfer (collective transfer). Thereby, 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 (15) by the transfer conveying belt (50). After the image transferred by the fixing device (15) is fixed, the transfer paper (P) is removed from the printer main body. To be discharged.

  The residual toner that is not transferred during the secondary transfer and remains on the intermediate transfer belt (22) is removed from the intermediate transfer belt (22) by the belt cleaning device (25). A lubricant application device (not shown) is disposed on the downstream side of the belt cleaning device (25). This lubricant application device includes a solid lubricant and a conductive brush that rubs the intermediate transfer belt (22) to apply the solid lubricant. The conductive brush is always in contact with the intermediate transfer belt (22) and applies a solid lubricant to the intermediate transfer belt (22). The solid lubricant has an effect of improving the cleaning property of the intermediate transfer belt (22), preventing the occurrence of filming and improving the durability.

  The seamless belt according to the present invention can be preferably applied to an intermediate transfer belt type image forming apparatus equipped with the intermediate transfer belt (501) or (22) as described above, and the intermediate transfer belt (501) or ( The present invention can also be applied to a transfer / conveying belt type image forming apparatus equipped with a transfer / conveying belt instead of 22). 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 without departing from the gist thereof.

Example 1
The following constituent materials were mixed and defoamed with a centrifugal stirring defoamer to obtain a coating solution.
<Coating liquid constituent material>
Polyimide solution U-Varnish A (Ube Industries; solid content 18 wt%) 50 parts by weight Polyimide solution U-Varnish S (Ube Industries; solid content 18 wt%) 50 parts by weight Polyether-modified silicon FZ2105 (Toray Dow Corning) 0.01 weight Part Using the coating solution, a seamless belt was produced as follows.

[Preparation of seamless belt 1]
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 coating has spread evenly after the predetermined amount has been flown, the number of rotations is increased to 500 rpm, the hot air circulating dryer is introduced, the temperature is raised to 120 ° C. at a heating rate of 5 ° C./min, and heating is performed for 30 minutes. did. Thereafter, the rotation was stopped, the mixture was put into a heating furnace (baking furnace) capable of high temperature treatment, heated to 320 ° C. at a heating rate of 5 ° C./min, and heated (baked) for 15 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 from the inner surface of the cylinder to obtain a seamless belt 1 having a film thickness of 80 μm.

[Supercritical carbon dioxide treatment of seamless belt 1]
The manufactured seamless belt is put into the extraction tank (4) of the apparatus in FIG. 3, and supercritical carbon dioxide is circulated at a flow rate of 400 ml / min (standard state conversion value), 45 ° C., 30 MPa, for 30 minutes, Residual N-methyl-2-pyrrolidone in the belt was extracted and removed, the inside of the container was returned to normal pressure, the belt was taken out, and belt 1-A was obtained.

(Comparative Example 1)
The seamless belt 1 was not subjected to the supercritical carbon dioxide treatment in Example 1.

(Comparative Example 2)
A seamless belt 2 was produced using the coating solution in Example 1 under the following conditions.
[Preparation of seamless belt 2]
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 coating has spread evenly after the predetermined amount has been flowed, the number of revolutions is increased to 500 rpm, the hot air circulating dryer is charged, the temperature is increased to 140 ° C. at a temperature increase rate of 3 ° C./min, and heating is performed for 90 minutes. did. Thereafter, the rotation was stopped, the mixture was put into a heating furnace (baking furnace) capable of high temperature treatment, heated to 400 ° C. at a heating rate of 2 ° C./min, and subjected to heat treatment (baking) for 30 minutes.
After stopping the heating 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 2 having a film thickness of 80 μm.

(Example 2)
The following constituent materials were mixed and defoamed with a centrifugal stirring defoamer to obtain a coating solution.
<Coating liquid constituent material>
Polyamideimide solution HR16NN (Toyobo; solid content 15 wt%) 100 parts by weight Polyether-modified silicone FZ2105 (Toray Dow Corning) 0.01 part by weight Using the above coating solution, a seamless belt was prepared as follows.

[Preparation of seamless belt 3]
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 coating has spread evenly after the predetermined amount has been flown, the number of rotations is increased to 500 rpm, the hot air circulating dryer is introduced, the temperature is raised to 120 ° C. at a heating rate of 5 ° C./min, and heating is performed for 30 minutes. did. Thereafter, the rotation was stopped, the mixture was put into a heating furnace (firing furnace) capable of high temperature treatment, heated to 260 ° C. at a heating rate of 5 ° C./min, and heat-treated (firing) for 15 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 3 having a film thickness of 80 μm.

[Supercritical carbon dioxide treatment of seamless belt 3]
The manufactured seamless belt is put into the extraction tank (4) of the apparatus in FIG. 3, and supercritical carbon dioxide is circulated at a flow rate of 400 ml / min (standard state conversion value), 45 ° C., 30 MPa, for 30 minutes, Residual N-methyl-2-pyrrolidone in the belt was extracted and removed, the inside of the container was returned to normal pressure, the belt was taken out, and belt 3-A was obtained.

(Comparative Example 3)
The seamless belt 3 was not subjected to the supercritical carbon dioxide treatment in Example 2.

(Comparative Example 4)
A seamless belt 4 was produced using the coating liquid in Example 2 under the following conditions.
[Preparation of seamless belt 4]
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 coating has spread evenly after the predetermined amount has been flowed, the number of revolutions is increased to 500 rpm, the hot air circulating dryer is charged, the temperature is increased to 140 ° C. at a temperature increase rate of 3 ° C./min, and heating is performed for 90 minutes. did. Thereafter, the rotation was stopped, the mixture was put into a heating furnace (firing furnace) capable of high temperature treatment, heated to 300 ° C. at a temperature rising rate of 2 ° C./min, and heat-treated (firing) 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 4 having a film thickness of 80 μm.

About the said various belts, the residual solvent was measured with the heat extraction gas chromatograph mass spectrometer.
Further, the number of bending breaks was measured with an MIT weather resistance tester DA (Toyo Seiki).
The measurement conditions are as follows.
<Measurement conditions for MIT weather resistance test>
Sample width: 15mm
Bending speed: 175 times / min Bending angle: 135 degrees Number of bendings: The number of bendings until the sample breaks is measured.
The results are shown in Table 1.

以上のように、超臨界二酸化炭素処理を行なうことで残留溶媒を確実に抽出することができた。また、残留溶媒を低減する乾燥条件にて作製したベルトに比べ、耐屈曲性に優れるシームレスベルトが得られた。

As described above, the residual solvent could be reliably extracted by performing the supercritical carbon dioxide treatment. In addition, a seamless belt excellent in bending resistance was obtained as compared with a belt produced under dry conditions for reducing residual solvent.

(Example 3)
[Preparation of coating solution]
First, the following constituent materials were mixed and dispersed using a zirconia bead of φ1 mm for 5 hours with a bead mill disperser to prepare a carbon dispersion.
<Dispersion composition material>
Polyimide solution U-varnish S (Ube Industries; solid content 18 wt%) 2 parts by weight Carbon black Special black 4 (Degussa) 10 parts by weight N-methyl-2-pyrrolidone (Mitsubishi Chemical) 88 parts by weight Using the above dispersion, The constituent materials were mixed, mixed and defoamed with a centrifugal stirring deaerator to obtain a coating solution.
<Coating liquid constituent material>
Carbon black dispersion 50 parts by weight Polyimide solution U-varnish A (Ube Industries; solid content 18 wt%) 50 parts by weight Polyimide solution U-varnish S (Ube Industries; solid content 18 wt%) 50 parts by weight Polyether-modified silicon FZ2105 ( Toray Dow Corning) 0.01 parts by weight

[Preparation of seamless belt 5]
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 coating has spread evenly after the predetermined amount has been flown, the number of rotations is increased to 500 rpm, the hot air circulating dryer is introduced, the temperature is raised to 120 ° C. at a heating rate of 5 ° C./min, and heating is performed for 30 minutes. did. Thereafter, the rotation was stopped, the mixture was put into a heating furnace (baking furnace) capable of high temperature treatment, heated to 300 ° C. at a heating rate of 5 ° C./min, and subjected to heat treatment (baking) for 40 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 5 having a film thickness of 80 μm.

[Supercritical carbon dioxide treatment of seamless belt 5]
The manufactured seamless belt is put into the extraction tank (4) of the apparatus in FIG. 3, and supercritical carbon dioxide is circulated at a flow rate of 400 ml / min (standard state conversion value), 45 ° C., 30 MPa, for 30 minutes, Residual N-methyl-2-pyrrolidone in the belt was extracted and removed, the inside of the container was returned to normal pressure, the belt was taken out, and belt 5-A was obtained.

(Comparative Example 5)
The seamless belt 5 was not subjected to the supercritical carbon dioxide treatment in Example 3.

(Comparative Example 6)
The production conditions of the seamless belt of Example 3 were the same except that the following conditions were used.
[Preparation of seamless belt 6]
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 coating has spread evenly after the predetermined amount has been flowed, the number of revolutions is increased to 500 rpm, the hot air circulating dryer is charged, the temperature is increased to 140 ° C. at a temperature increase rate of 3 ° C./min, and heating is performed for 90 minutes. did. Thereafter, the rotation was stopped, the mixture was put into a heating furnace (baking furnace) capable of high temperature treatment, heated to 400 ° C. at a heating rate of 2 ° C./min, 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 6 having a film thickness of 80 μm.

Example 4
[Preparation of coating solution]
First, the following constituent materials were mixed and dispersed using a zirconia bead of φ1 mm for 5 hours with a bead mill disperser to prepare a carbon dispersion.
<Dispersion composition material>
Polyamideimide solution HR16NN (Toyobo; solid content 15 wt%) 2 parts by weight Carbon black MA77 (Mitsubishi Chemical) 10 parts by weight N-methyl-2-pyrrolidone (Mitsubishi Chemical) 88 parts by weight Using the above dispersion, the following constitution The materials were mixed, mixed and defoamed with a centrifugal stirring defoamer to obtain a coating solution.
<Coating liquid constituent material>
Carbon black dispersion 50 parts by weight Polyamideimide solution HR16NN (Toyobo; solid content 15 wt%) 100 parts by weight Polyether-modified silicone FZ2105 (Toray Dow Corning) 0.01 part by weight

[Preparation of seamless belt 7]
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 coating has spread evenly after the predetermined amount has been flown, the number of rotations is increased to 500 rpm, the hot air circulating dryer is introduced, the temperature is raised to 120 ° C. at a heating rate of 5 ° C./min, and heating is performed for 30 minutes. did. Thereafter, the rotation was stopped, and the mixture was put into a heating furnace (baking furnace) capable of high temperature treatment, heated to 240 ° C. at a heating rate of 5 ° C./min, and subjected to heat treatment (baking) for 40 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 7 having a film thickness of 80 μm.

[Supercritical carbon dioxide treatment of seamless belt 7]
The manufactured seamless belt is put into the extraction tank (4) of the apparatus in FIG. 3, and supercritical carbon dioxide is circulated at a flow rate of 400 ml / min (standard state conversion value), 45 ° C., 30 MPa, for 30 minutes, Residual N-methyl-2-pyrrolidone in the belt was extracted and removed, the inside of the container was returned to normal pressure, the belt was taken out, and belt 7-A was obtained.

(Comparative Example 7)
The seamless belt 7 was not subjected to the supercritical carbon dioxide treatment in Example 4.

(Comparative Example 8)
The production conditions of the seamless belt of Example 3 were the same except that the following conditions were used.
[Preparation of seamless belt 8]
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 coating has spread evenly after the predetermined amount has been flowed, the number of revolutions is increased to 500 rpm, the hot air circulating dryer is charged, the temperature is increased to 140 ° C. at a temperature increase rate of 3 ° C./min, and heating is performed for 90 minutes. did. Thereafter, the rotation was stopped, the mixture was put into a heating furnace (firing furnace) capable of high temperature treatment, heated to 300 ° C. at a temperature rising rate of 2 ° C./min, and heat-treated (firing) 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 8 having a film thickness of 80 μm.

(Example 5)
A seamless belt was produced using the coating solution in Example 3 under the following conditions.
[Preparation of seamless belt 9]
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 coating has spread evenly after the predetermined amount has been flowed, the number of rotations is increased to 500 rpm, the hot air circulating dryer is introduced, the temperature is raised to 80 ° C. at a heating rate of 5 ° C./min, and heated for 20 minutes. did. Thereafter, the rotation was stopped, the mixture was put into a heating furnace (firing furnace) capable of high temperature treatment, heated to 280 ° C. at a temperature rising rate of 5 ° C./min, and heat-treated (firing) for 15 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 9 having a film thickness of 80 μm.

[Supercritical carbon dioxide treatment of seamless belt 9]
The manufactured seamless belt is put into the extraction tank (4) of the apparatus in FIG. 3, and supercritical carbon dioxide is circulated at a flow rate of 400 ml / min (standard state conversion value), 45 ° C., 30 MPa, for 30 minutes, Residual N-methyl-2-pyrrolidone in the belt was extracted and removed, the inside of the container was returned to normal pressure, the belt was taken out, and belt 9-A was obtained.

For the various belts, the residual solvent was measured in the same manner by pyrolysis gas chromatography.
Further, the number of bending breaks was measured with an MIT weather resistance tester DA (Toyo Seiki).
2 was mounted as an intermediate transfer belt of the apparatus of FIG. 2, and image evaluation and belt state confirmation were performed when 10,000 full-color images were output continuously in an environment of 25 ° C. and 50% and 30 ° C. and 80%.
The results are shown in Table 2.

As described above, it was possible to obtain an intermediate transfer belt excellent in mechanical strength from which residual solvent was reliably removed by supercritical carbon dioxide treatment. If the residual solvent is reduced without the supercritical carbon dioxide treatment, sufficient mechanical strength cannot be obtained, and there is a problem in practical use.
Further, if the amount of residual solvent before the supercritical carbon dioxide treatment is too large (exceeding 5 wt%), color shift occurs in a high humidity environment, which is not very practically preferable.

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. It is a schematic diagram of a supercritical carbon dioxide processing apparatus.

Explanation of symbols

(Figure 1)
P Transfer paper 70 Static elimination roller 80 Ground roller 200 Photosensitive drum 201 Photoconductor cleaning device 202 Static elimination lamp 203 Charging charger 204 Potential sensor 205 Toner image density sensor 210 Belt conveyor 230 Revolver developing unit 231Y Y developing machine 231K Bk developing machine 231C C Developer 231M M Developer 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 506 Lubricant 507 Primary transfer bias roller 508 Belt drive roller 509 Belt Tension controller 510 Secondary transfer counter roller 511 Cleaning counter roller 512 Feedback current detection roller 513 Toner image 514 Optical sensor 6 00 Secondary transfer unit 601 Transfer paper guide plate 605 Secondary transfer bias roller 606 Transfer paper neutralization charger 608 Cleaning blade 610 Registration roller 801 Primary transfer power source 802 Secondary transfer power source (FIG. 2)
P Transfer paper 10 Printer body 12 Image writing unit 13 Image forming unit 14 Paper feeding unit 15 Fixing device 16 Registration rollers 20BK, 20M, 20Y, 20C Developing devices 21BK, 21M, 21Y, 21C Photoconductor 22 Intermediate transfer belts 23BK, 23M , 23Y, 23C Primary transfer bias roller 25 Belt cleaning device 50 Transfer conveyance belt 60 Secondary transfer bias roller (FIG. 3)
1 High-pressure liquid feed pump 2 Stop valve 3 Filter 4 Extraction tank 5 Stirrer 6 Filter 7 Back pressure valve 8 Flow meter T Thermometer P Pressure gauge

Claims (12)

In an electrophotographic seamless belt formed by applying and drying a coating solution comprising at least a polyimide precursor or a polyamideimide precursor organic polar solvent solution or a solvent-soluble polyimide solution, the seamless belt is supercritical. A seamless belt for electrophotography, which is subjected to a treatment for contact with at least one of carbon dioxide and subcritical carbon dioxide, and has a residual solvent amount of less than 0.1 wt%. The seamless belt for electrophotography according to claim 1, wherein the seamless belt has a folding endurance of 1000 or more according to the MIT weather resistance test. The seamless belt for electrophotography according to claim 1, wherein the seamless belt contains a resistance adjusting agent. 4. A seamless belt for a belt constituting part provided in an electrophotographic apparatus for transferring a toner developed image formed on an image carrier to form an image on a recording medium, wherein the belt is any one of claims 1 to 3. A seamless belt for a belt component, which is the seamless belt described in 1. An electrophotographic apparatus for performing a 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 a secondary transfer of the primary transfer image collectively to a recording medium. 4. A seamless belt for a belt component according to claim 1, wherein the intermediate transfer belt is the seamless belt according to any one of claims 1 to 3. 4. An electrophotographic apparatus comprising a belt constituting unit that transfers a toner developed image formed on an image carrier to form an image on a recording medium, and the belt is a seamless belt according to any one of claims 1 to 3. An electrophotographic apparatus characterized by being a belt. 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 primary transfer image is collectively transferred to a recording medium and subjected to secondary transfer. 4. The electrophotographic apparatus according to claim 1, wherein the intermediate transfer belt is the seamless belt according to claim 1. An application step of applying a coating solution comprising at least a polyimide precursor or a polyamideimide precursor organic polar solvent solution, or a solvent-soluble polyimide solution on the surface of the mold at a predetermined thickness, a drying step of drying the applied mold by heating, A cooling process for cooling the dried mold, a demolding process for removing the film from the cooled mold, and a treatment process for bringing the seamless belt obtained by demolding into contact with at least one of supercritical carbon dioxide and subcritical carbon dioxide. A method for producing a seamless belt for electrophotography characterized by the above. An application step of applying a coating solution comprising at least a polyimide precursor or a polyamideimide precursor organic polar solvent solution, or a solvent-soluble polyimide solution on the surface of the mold at a predetermined thickness, a drying step of drying the applied mold by heating, An electron having a cooling process for cooling the mold after drying, a demolding process for removing the film from the cooled mold, and a processing process for bringing the seamless belt obtained by demolding into contact with at least one of supercritical carbon dioxide and subcritical carbon dioxide. In the method for producing a photographic seamless belt, the seamless belt is produced under the condition that the residual solvent amount of the solvent in the demolding step is 0.1 to 5 wt%, and the processing step is less than 0.1 wt%. A method for producing a seamless belt for electrophotography characterized by the above. A step of dispersing a resistance adjusting agent in an organic polar solvent solution of at least a polyimide precursor or a polyamideimide precursor, or a solvent-soluble polyimide solution, and a coating that applies a coating solution produced by the step to a mold surface with a predetermined thickness Process, drying process to heat-dry the coated mold, cooling process to cool the mold after drying, demolding process to take out the film from the cooled mold, seamless belt obtained by demolding is supercritical carbon dioxide or subcritical A process for producing an intermediate transfer belt for electrophotography, comprising a treatment step of contacting with at least one of carbon dioxide. A step of dispersing a resistance adjusting agent in an organic polar solvent solution of at least a polyimide precursor or a polyamideimide precursor, or a solvent-soluble polyimide solution, and a coating that applies a coating solution produced by the step to a mold surface with a predetermined thickness Process, drying process to heat-dry the coated mold, cooling process to cool the mold after drying, demolding process to take out the film from the cooled mold, seamless belt obtained by demolding is supercritical carbon dioxide or subcritical In the method for producing an electrophotographic intermediate transfer belt having a processing step of contacting with at least one of carbon dioxide, the intermediate transfer belt is subjected to a condition that a residual solvent amount in a demolding step is 0.1 to 5 wt%. A method for producing an intermediate transfer belt for electrophotography, which is produced and becomes less than 0.1 wt% by the treatment step. The method of manufacturing an intermediate transfer belt according to claim 10 or 11, wherein the intermediate transfer belt has a folding endurance of 1000 or more by an MIT weather resistance test.

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