JP2010237632A - Belt for electrophotography, method of manufacturing the same, and electrophotographic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt for electrophotography having a desired resistance value and high uniformity by stable additive amount of carbon, good in mechanical strength, superior in flame retardancy and yielding a high-durability, high quality and high function image regardless of a lot in a production process and a lot of material such as carbon black and resin. <P>SOLUTION: In the method of manufacturing the belt for electrophotography, the belt for electrophotography is manufactured by applying a coating liquid produced through a step of producing a dispersion liquid containing at least carbon black, resin and a solvent and a step of producing the coating liquid prepared by using the dispersion liquid to an outer surface of a metal mold or an inner surface of a cylindrical metal mold, and drying and/or curing it to form a film and removing it from the mold, wherein a dispersion liquid having black density being ≥2.200 and ≤2.500 by a spectral density meter of the film formed on a substrate by using the same is used as the dispersion liquid. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrophotographic belt installed in an image forming apparatus such as a copy printer, and an image forming apparatus using the belt, and more particularly to an intermediate transfer belt suitable for full-color image formation and an image forming apparatus using the belt.

  2. Description of the Related Art Conventionally, electrophotographic belts have been used as members for various purposes such as an intermediate transfer belt and a paper supply / discharge belt in an electrophotographic apparatus. Particularly in recent full-color electrophotographic apparatuses, an intermediate transfer belt that temporarily superimposes developed images of four colors of yellow, magenta, cyan, and black on an intermediate transfer medium and then collectively transfers them onto a transfer medium such as paper. The method is used.

  Such an intermediate transfer belt system has been used in a system that uses four color developing devices for one photoconductor, but has a drawback in that the printing speed is slow. As the high-speed printing, a four-tandem tandem system is used in which the photoreceptors are arranged for four colors and each color is continuously transferred to paper. However, in this method, there are fluctuations due to the environment of the paper, etc., and it is very difficult to match the position accuracy of overlapping each color image, causing a color misregistration image. Therefore, in recent years, it has become the mainstream to adopt the intermediate transfer method for the quadruple tandem method.

  For this reason, it has become necessary for the intermediate transfer belt to satisfy characteristics corresponding to requirements such as high speed and positional accuracy. In particular, for positional accuracy, it is required to suppress fluctuation due to deformation such as elongation of the belt itself due to continuous use. Further, since the intermediate transfer belt is laid out over a wide area of the apparatus and a high voltage for transfer is applied, flame retardancy is also required. Accordingly, polyimide resins, polyamideimide resins, and the like that are high elastic modulus and high heat resistance resins are mainly used.

Further, in the intermediate transfer belt system, it is necessary to adjust to a certain resistance value in order to transfer an image of charged toner by the action of an electric field.
The resistance value is generally adjusted to about 1 × 10 ⁷ to 1 × 10 ¹³ Ω / □ as the surface resistance value and about 1 × 10 ⁵ to 1 × 10 ¹² Ωcm as the volume resistance value.

  Such a resistance value is adjusted by dispersing organic or inorganic conductive fine particles or by containing a material such as a conductive polymer or an ionic conductive agent in the resin. Among these, carbon black is most preferably used.

  When a polyimide resin or a polyamideimide resin is used as the resin for the intermediate transfer belt, carbon black is particularly preferably used. Polyimide resins and polyamideimide resins are formed by heat-curing a resin solution dissolved in a polar solvent. The polar solvent used for this, particularly N-methyl-2-pyrrolidone, preferably acts on the dispersibility of carbon black. Therefore, it is preferably used.

In order to disperse carbon black in a polyimide resin or a polyamideimide resin, carbon is dispersed in a fine particle state having a desired particle diameter in a solvent using a general-purpose disperser such as a bead mill, a ball mill, a paint shaker, or a planetary ball mill. Then, using the resin solution in which carbon is dispersed, a uniform intermediate transfer belt having a desired resistance value and no variation is manufactured.
In order to obtain a preferable electrical characteristic as an intermediate transfer belt, the following proposals have been made.

Patent Documents 1 to 6 propose a method capable of realizing suitable dispersion in a polyimide resin by using a carbon black surface treatment or a dispersant. Moreover, in patent document 7, the largest coarse particle diameter of carbon is prescribed | regulated. Patent Document 8 proposes to improve the dispersibility of carbon by the molecular weight of polyamideimide.
Patent Documents 9 to 10 propose that the variation of the particle size when a carbon dispersion is used as a coating solution is specified.
In patent document 11, the black density of the composition containing carbon is prescribed | regulated.

  However, in production, the problem is that the amount of carbon added and variations to obtain the desired resistance value vary depending on the production process lot and lots of materials such as carbon black and resin, resulting in defective products and unstable production. was there.

  The object of the present invention is to achieve a desired resistance value and a high uniformity with a stable carbon addition amount, a high mechanical strength, and a flame retardance regardless of the production process lot or the lot of materials such as carbon black and resin. An object of the present invention is to provide an electrophotographic belt capable of obtaining excellent, high durability, high quality and high performance images.

The said subject is solved by following (1)-(5) of this invention.
(1) “Produced by a step of preparing a dispersion liquid containing at least carbon black, a resin and a solvent on the outer surface of a mold or an inner surface of a cylindrical mold, and a step of preparing a coating liquid prepared using the dispersion liquid. In a method for producing an electrophotographic belt, which is produced by applying a coated coating solution, forming a film by drying and / or curing it, and demolding the coating solution. A method for producing an electrophotographic belt, characterized by using a dispersion having a black density of 2.200 or more and 2.500 or less in a spectral densitometer of the film when the film is formed ",
(2) "The method for producing an electrophotographic belt according to (1) above, wherein the electrophotographic belt is a polyimide resin or a polyamide-imide resin",
(3) “In an electrophotographic apparatus including an electrophotographic belt, the electrophotographic belt is manufactured by the manufacturing method according to the item (1) or (2)”. Electrophotographic device ",
(4) An electrophotographic apparatus using an intermediate transfer belt, wherein the intermediate transfer belt is manufactured by the manufacturing method according to the item (1) or (2). "
(5) “Electrophotographic apparatus according to item (4), wherein the carbon black content of the intermediate transfer belt is 15 wt% or more and 25 wt% or less”.

According to the present invention, there are provided a seamless belt, an electrophotographic belt such as an intermediate transfer belt, and an image forming apparatus using the electrophotographic belt, which are used in an image forming apparatus having the following effects which has improved the problems of the prior art. Provided.
According to the invention of (1), it is possible to obtain an electrophotographic belt having a desired resistance value and high uniformity with a stable carbon addition amount regardless of a lot of a production process or a lot of materials such as carbon black and resin. .
According to the invention of (2), an electrophotographic belt having high mechanical strength and high flame retardancy can be obtained.
According to the invention of (3), a highly durable and highly functional electrophotographic apparatus can be obtained.
According to the invention of (4), an electrophotographic apparatus using an intermediate transfer belt that provides an image with high durability and high quality can be obtained.
According to the invention of (5), it is possible to obtain an electrophotographic apparatus using an intermediate transfer belt that provides a higher durability and higher quality image.

FIG. 2 is a schematic diagram of a main part for explaining an intermediate transfer belt used for a belt member of the image forming apparatus according to the present invention and an image forming apparatus using the intermediate transfer belt. FIG. 2 is a schematic diagram of a main part illustrating a configuration example of an image forming apparatus in which a plurality of photosensitive drums are arranged in parallel along one intermediate transfer belt provided as a belt member of the image forming apparatus according to the present invention. 1 is a schematic view of a pass-type dispersion apparatus for producing a carbon black dispersion. FIG. The schematic diagram of the dispersion apparatus of the circulation system which manufactures the dispersion liquid of carbon black is shown.

In an electrophotographic apparatus, a seamless belt is used for several members, and an intermediate transfer belt is one of important members that require electrical characteristics.
Hereinafter, the electrophotographic belt of the present invention, particularly the intermediate transfer belt will be described.

  The intermediate transfer belt of the present invention includes, as a constituent material thereof, a general general-purpose resin containing a filler for adjusting electric resistance. The resin is preferably a fluorine-based resin such as PVDF or ETFE, polyimide or polyamideimide from the viewpoint of flame retardancy, but in terms of mechanical strength and dispersibility of the resistance control filler, polyimide resin or polyamide. An imide resin is preferred.

On the other hand, as the filler for adjusting electric resistance, organic or inorganic conductive fine particles such as metals, metal oxides, and carbon black, ionic conductive agents, and conductive polymers are used, but they are inexpensive and excellent in productivity. Carbon black is preferably used.
Examples of carbon black include ketjen black, furnace black, acetylene black, thermal black, and gas black.
Among these, those that are compatible with the solvent or resin to be used are selected and used.
Also, those obtained by appropriately surface-treating these carbon blacks can be used. Carbon black is used as the resistance adjusting agent, but other resistance adjusting agents described above may be used in combination.

When used as an intermediate transfer belt, carbon having a resistance value of preferably 1 × 10 ⁸ to 1 × 10 ¹³ Ω / □ and a volume resistance of 1 × 10 ⁶ to 1 × 10 ¹² Ω · cm is preferable. A black amount is contained, but from the viewpoint of mechanical strength, a material that can be achieved with an addition amount that is not brittle and does not easily break is selected.

  The carbon black content in the present invention is 10 to 30 wt%, preferably 15 to 25 wt% of the total solid content. If it is less than this, it is difficult to obtain uniformity in resistance value, and the withstand voltage is low, which is not preferable. On the other hand, if it exceeds this, the mechanical strength of the belt is lowered and the durability is inferior.

Next, the polyimide resin will be described.
<Polyimide>
The polyimide used in the present invention is obtained via a polyamic acid (polyimide precursor) by a reaction between a generally known aromatic polycarboxylic acid anhydride or derivative thereof and an aromatic diamine. That is, polyimide is insoluble in solvents due to its rigid main chain structure, and has infusible properties, so it is first soluble in organic solvents from aromatic polycarboxylic anhydrides and aromatic diamines. A new polyimide precursor (polyamic acid or polyamic acid), and at this stage, molding is performed by various methods, and then the polyamic acid is dehydrated by heating or chemical methods to cyclize (imidize) And polyimide. The outline of the reaction is shown in the following formula (1).

（式中、Ａｒ^１は少なくとも１つの炭素６員環を含む４価の芳香族残基を示し、Ａｒ^２は少なくとも１つの炭素６員環を含む２価の芳香族残基を示す。）

(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 polycarboxylic acid anhydride include, for example, cyclopentanetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride 2,2 ′, 3,3′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic Acid 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-dicarboxypheny ) Methane dianhydride, 2,2-bis (3,4-dicarboxylphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 2,3,6,7-naphthalenetetra Carboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic acid Dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride Examples of other polyvalent carboxylic acid anhydrides include ethylene tetracarboxylic dianhydride. 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. In order to effectively express the physical properties of the present invention, it is particularly preferable to use 4,4'-diaminodiphenyl ether as at least one of the components.

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 for 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 hexa Chill phosphoramide, .gamma.-butyrolactone, etc. may be mentioned, it is desirable to use them alone or as a mixed solvent. The solvent is not particularly limited as long as it dissolves polyamic acid, but N, N-dimethylacetamide and N-methyl-2-pyrrolidone are particularly preferable.

  As an example in the case of producing a polyimide precursor, first, one or a plurality of diamines are dissolved in the above organic solvent or dispersed in a slurry state in an inert gas atmosphere such as argon or nitrogen. When at least one aromatic polycarboxylic acid anhydride or derivative thereof is added to this solution (either in a solid state, in a solution state dissolved in an organic solvent, or in a slurry state), it generates heat. A ring-opening polyaddition reaction occurs, and the viscosity of the solution rapidly increases, and a high molecular weight polyamic acid solution is obtained. In this case, the reaction temperature is usually controlled to −20 ° C. to 100 ° C., desirably 60 ° C. or less. The reaction time is about 30 minutes to 12 hours.

  The above is an example. Contrary to the addition procedure in the reaction, the aromatic polycarboxylic acid anhydride or derivative thereof is first dissolved or diffused in an organic solvent, and the diamine may be added to this solution. Good. The diamine may be added in a solid state, in a solution state dissolved in an organic solvent, or in a slurry state. That is, the mixing order of the acid dianhydride component and the diamine component is not limited. Further, the aromatic tetracarboxylic dianhydride and the aromatic diamine may be simultaneously added to the organic polar solvent for reaction.

  As described above, an aromatic polyvalent carboxylic acid anhydride or derivative thereof and an aromatic diamine component are polymerized in about an equimolar amount in an organic polar solvent, so that the polyamic acid is uniformly dispersed in the organic polar solvent. A polyimide precursor solution is obtained in a dissolved state.

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

  A coating solution is prepared by mixing and dispersing a filler in the synthesized or obtained polyamic acid solution as necessary. 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.

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

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 resonance spectroscopy calculated from an integration ratio of 1H attributed to an amide group in the vicinity of 9 to 11 ppm and 1H attributed to an aromatic ring in the vicinity of 6 to 9 ppm. Various methods are used such as a method (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. Outer spectroscopy (FT-IR method) is the most common method.

In the Fourier transform infrared spectroscopy (FT-IR method), the imidization rate is defined as, for example, the following formula (a).
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.

この定義におけるイミド基のモル数は、ＦＴ−ＩＲ法により測定されるイミド基の特性吸収の吸光度比から求めることができる。例えば、代表的な特性吸収として、以下の吸光度比を用いてイミド化率を評価することができる。

The number of moles of the imide group in this definition can be determined from the absorbance ratio of the characteristic absorption of the imide group measured by the FT-IR method. For example, as a typical characteristic absorption, the imidization ratio can be evaluated using the following absorbance ratio.

(1) Absorbance ratio between 725 cm ⁻¹ (immobilization vibration band of imide ring C═O group) which is one of characteristic absorptions of imide and 1,015 cm ⁻¹ of characteristic absorption of benzene ring (2) Characteristics of imide to be one of absorbing 1,380Cm ^-1 (deformation vibration band of an imide ring C-N group), the absorbance ratio of the characteristic absorption 1,500Cm ^-1 benzene ring (3) one of the characteristic absorption of an imide Absorption ratio between 1,720 cm ⁻¹ (an azimuthal vibration band of the imide ring C═O group) and 1,500 cm ⁻¹ characteristic absorption of the benzene ring (4) 1, which is one of characteristic absorption of imide Absorbance ratio between 720 cm ⁻¹ and amide group characteristic absorption 1,670 cm ⁻¹ (interaction between amide group N—H bending vibration and CN stretching vibration) and amide group over 3000 to 3300 cm ⁻¹ Confirm that the multiple absorption bands from Further more reliable imidization complete if.

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

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

（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 Structural Formula (2) or Structural Formula (3), examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom, with a chlorine atom being preferred. Most representative is trimellitic anhydride chloride.
A derivative halide of a trivalent carboxylic acid compound having an acid anhydride group represented by the structural formula (2) or the structural formula (3) is an example of a raw material for obtaining an aromatic polyamideimide. Is not something
In addition to the aromatic trivalent carboxylic acid compound represented by the structural formula (2) or structural formula (3), a derivative halide of a trivalent carboxylic acid compound having an aliphatic acid anhydride group can also be used. Yes, it can be used in combination with aromatic derivatives.

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.

A polyamic acid is prepared by applying a coating liquid containing carbon black, which is prepared using the polyamide / polyamic acid solution obtained as described above, and well dispersed to a support (molding mold), and then treating it with heating. Is converted to polyimide (imidation).
Examples of the imidization method include a method of dehydrating and ring-closing by heat treatment, and a method of chemically ring-closing using a dehydrating and ring-closing catalyst. When dehydrating and ring-closing by heat treatment, for example, the reaction temperature is 150 to 400 ° C., preferably 180 to 350 ° C., and the heat treatment time is 30 seconds to 10 hours, preferably 5 minutes to 5 hours. When a dehydration ring closure catalyst is used, the reaction temperature is 0 to 180 ° C., preferably 10 to 80 ° C., and the reaction time is several tens of minutes to several days, preferably 2 to 12 hours. Examples of the dehydration ring closure catalyst include acid anhydrides such as acetic acid, propionic acid, butyric acid, and benzoic acid.

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

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

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

  After applying a solution containing a polyamideimide precursor obtained by adjusting the above-described trivalent carboxylic acid derivative having an acid anhydride group and an aromatic polyisocyanate in an organic polar solvent, heat treatment is performed. By doing so, the conversion from the polyamideimide precursor to the polyamideimide is performed. Upon conversion to polyamideimide by this method, polyamideimide is generated without generating a carbonic acid (generally generating carbon dioxide). The following formula (6) shows an example of polyamide imidization when trimellitic anhydride and aromatic isocyanate are used.

（式中、Ａｒは芳香族基を示す。）

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

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

Next, as a method of manufacturing an intermediate transfer belt using the coating liquid containing the polyimide precursor or the polyamideimide precursor, a method of forming a film by applying to the inner surface of a cylindrical mold, There is a method of forming a film by coating on the outer surface of the film.
In the present invention, both methods can be used.
Hereinafter, centrifugal molding, which is one of methods for forming a film on the inner surface, will be described.

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

Next, a method for preparing the coating solution used above will be described.
The coating liquid in the present invention is prepared by at least a step of preparing a dispersion liquid containing carbon black, a resin and a solvent, and a step of mixing the resin with the dispersion liquid and adjusting the content of carbon black to a predetermined amount. .

First, in the step of preparing a dispersion, a solution in which at least a polyimide or polyamideimide precursor solution and carbon black are mixed in a solvent is added to a carbon black using a disperser such as a bead mill, a ball mill, a nanomizer, a paint shaker, or a jet mill. To prepare a dispersion.
At this time, you may contain additives, such as various dispersing agents, as needed. Further, carbon black that has been subjected to some treatment in advance may be used.
Hereinafter, dispersion by a bead mill will be described as an example.

FIG. 3 shows a bead mill dispersing apparatus using a pass method.
The liquid to be dispersed is put into the tank A, and the liquid is sent to the disperser by a liquid feed pump. The disperser is filled with beads of a certain size, and this has a mechanism that rotates at high speed inside, and carbon black is atomized by the rubbing force by the beads by this rotation.
The atomized liquid is collected in the tank B, and one pass is completed. The dispersion force at this time is determined by the rotational speed in the disperser, the type of beads, the diameter, and the flow rate of the liquid feeding, and these are set to appropriate conditions. When the dispersion state of the liquid recovered in the tank B is insufficient, the liquid is again introduced into the tank A and dispersion is performed again. In the pass method, this is repeated until a sufficiently dispersed liquid is obtained.

FIG. 4 shows a bead mill apparatus using a circulation system.
Unlike FIG. 3, the liquid dispersed by the disperser returns to the tank A. Dispersion proceeds while the liquid before dispersion and the liquid after dispersion are sufficiently stirred. In this method, dispersion evaluates the state of the liquid returning from the disperser. In general, management is performed in the time required for dispersion.

The carbon black content of this dispersion is preferably 5 to 15%.
The smaller the carbon black content, the easier it is to disperse. However, considering production, it is wasteful and expensive, so the content is 5% or more. On the other hand, if it is 15% or more, the dispersion efficiency is greatly lowered, and the dispersion stability of the dispersion deteriorates due to reaggregation of the carbon black particles after dispersion, which is not preferable.

The precursor solid content of polyimide or polyamideimide is preferably 5 to 40 parts with respect to 100 parts of carbon black.
Carbon black can be dispersed even if it does not contain a polyimide or polyamide imide precursor. However, when it is produced without containing it, in the next step of adjusting the carbon black content, this dispersion and polyimide or When mixing the polyamideimide precursor solution, carbon black is not preferable because it causes shock aggregation.
Therefore, it is preferable to contain 5 parts or more of a precursor solid content of polyimide or polyamideimide with respect to carbon black. On the other hand, when it is 40 parts or more, the viscosity of the solution becomes too high, and the dispersion efficiency is lowered, which is not preferable.

  You may use suitably additives, such as various dispersing agents, to a dispersion liquid as needed. Moreover, in dispersion | distribution, processes, such as a pre-mixing process and the other stage dispersion | distribution by a different disperser, can also be taken.

In the present invention, the dispersion state of carbon in this dispersion is important. As an index representing the dispersion state of carbon black, there is generally a particle size.
As a method for measuring the particle size, measurement is performed with a measuring instrument such as a centrifugal separation method, a laser diffraction method, or a dynamic light scattering method. For example, the particle size measured with a dynamic light scattering method measuring instrument is preferably dispersed in a volume average particle size of about 150 to 300 nm.
However, even if the particle size is dispersed to this extent, it is often impossible to obtain a product of good quality. In particular, depending on the production lot of carbon black, quality often varies and becomes defective.

In the present invention, this dispersion liquid is formed into a film, and the black density on the film surface is measured. In a dispersion having poor quality, the black density is low, and the black density increases as the quality improves. The black density on the film surface can be measured with a reflective spectral density measuring device.
The black density of the film surface by the dispersion for realizing good electrical property quality is preferably 2.200 or more. On the other hand, if it exceeds 2.500, the electrical property quality is good, but since a large amount of carbon is required to develop the required resistance value, the belt becomes brittle and durability in the electrophotographic apparatus is improved. Inferior and undesirable.

Next, the dispersion liquid prepared above is adjusted to have a predetermined resistance value by mixing and diluting a polyimide or polyamideimide precursor solution.
The method of mixing the polyimide or polyamideimide precursor solution into the dispersion is performed by stirring and mixing by using a general stirring device. Since the precursor solution of polyimide or polyamideimide has high viscosity, a machine that can cope with this is selected.
Moreover, since many bubbles are generated in the liquid after stirring, it is preferable to sufficiently remove the bubbles by a method such as vacuum defoaming.
Moreover, in this process, additives, such as a solvent and a leveling agent, can be contained as needed.

  Next, the intermediate transfer belt used in the belt constituting unit provided in the image forming apparatus according to the present invention will be described in detail below with reference to a schematic diagram of a main part. 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 a main part of an image forming apparatus equipped with a belt member 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.

  Further, 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. The negatively charged Bk toner on the developing roller of the Bk developing device (231K) comes into contact with the Bk electrostatic latent image, so that the toner adheres to the portion where the charge on 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 C image forming process after the Bk image forming process, and reading of the C image data by the color scanner starts at a predetermined timing. A C 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 C electrostatic latent image reaches, the revolver developing unit (230) is rotated, and the C developing machine ( 231C) is set at the development position, and the C electrostatic latent image is developed with C toner. Thereafter, development of the C electrostatic latent image area is continued, but when the rear end portion of the C electrostatic latent image passes, the revolver developing unit is rotated as in the case of the previous Bk developing machine (231K). Then, the next M developing machine (231M) is moved to the developing position. This is also completed before the leading edge of the next Y electrostatic latent image reaches the developing position. Note that the M and Y image forming steps are the same as the Bk and C steps described above because the operations of reading color image data, forming an electrostatic latent image, and developing are the same as those described above.

The Bk, C, M, and Y 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).

On the upstream side of the belt cleaning blade (504) in the moving direction of the intermediate transfer belt (501), a toner seal member (502) contacting and separating from the belt outer peripheral surface of the intermediate transfer belt (501) is provided. Yes.
The toner seal member (502) receives the falling toner that has dropped from the belt cleaning blade (504) during cleaning of the residual toner, and prevents the falling toner from scattering on the transfer path of the transfer paper (P). It is preventing. The toner seal member (502) 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, in the case 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 (Y) 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 four drums including four photosensitive drums (21BK), (21Y), (21M), and (21C) for forming toner images of four different colors (black, yellow, magenta, and cyan). 1 shows an example of the configuration of a type digital color printer.

In FIG. 2, the printer 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, and corresponds to each color signal described above. There are four writing optical paths, and image carriers (photoconductors) (21BK), (21M), (21Y), and (21C) provided for each color of the image forming unit (13) according to the respective color signals. Perform image writing.

The image forming unit (13) is a photoconductor (21BK), (21M), (21Y) which is an image carrier for black (BK), magenta (M), yellow (Y), and cyan (C). ), (21C). As each photoconductor for each color, an OPC photoconductor is usually used.
Around each of the photoconductors (21BK), (21M), (21Y), and (21C), there is a charging device, a laser beam exposure unit from the image writing unit (12), black, magenta, yellow, and cyan. Developing devices for each color (20BK), (20M), (20Y), (20C), primary transfer bias rollers (23BK), (23M), (23Y), (23C) as a primary transfer unit, cleaning devices (Not shown), a photoconductor neutralizing device (not shown), and the like are provided.
The developing devices (20BK), (20M), (20Y), and (20C) use a two-component magnetic brush developing system. The intermediate transfer belt (22), which is a belt component, includes the photosensitive members (21BK), (21M), (21Y), and (21C) and the primary transfer bias rollers (23BK), (23M), and (23Y). , (23C), and the toner images of the respective colors formed on the respective photoreceptors 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). As a result, a color image is formed on the transfer paper (P).
The transfer paper (P) on which the color image is formed is conveyed to the fixing device (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.

Residual toner remaining on the intermediate transfer belt (22) without being transferred during the secondary transfer is removed from the intermediate transfer belt (22) by the belt cleaning member (25).
A lubricant application device (27) is disposed downstream of the belt cleaning member (25). The lubricant application device (27) 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.

EXAMPLES Hereinafter, the present invention will be described more specifically based on examples. However, the present invention is not limited by these examples, and these examples are appropriately modified without departing from the gist of the present invention. Is also within the scope of the present invention.
[Examples and Comparative Examples]
(Production of carbon dispersion)
Polyimide solution (U-varnish A (solid content 18%); Ube Industries) 11 wt%
Carbon black (Special Black 4; Evonik Degussa) 10wt%
Solvent (N-methyl-2-pyrrolidone; BASF) 79 wt%

  The solution in which the above mixture was well mixed was dispersed by a pass method using a bead mill (Apex Mill; Kotobuki Industries). As the beads, zirconia beads having a diameter of 1 mm were used, and the number of passes was 3 passes, 6 passes, 10 passes, 13 passes, 16 passes, and 20 passes.

The particle diameter and black density of each dispersion obtained in each pass were measured by the following method.
<Measurement of particle size>
A liquid obtained by diluting the obtained dispersion liquid 200 times with N-methyl-2-pyrrolidone was prepared, and measurement was performed with Microtrac UPA150EX (Nikkiso Co., Ltd.).
<Measurement of black density>
A dispersion obtained by casting the dispersion with an applicator on a PET film was dried with a dryer at 100 ° C. for 15 minutes. After cooling, the surface of the dried coating film was measured for black density with a spectral densitometer X-rite 520 (X-Rite).
Table 1 shows the particle size and black density results of each dispersion.

Next, the following coating solutions were prepared using the above dispersions.
Above dispersion X wt%
Polyimide solution (U-varnish A (solid content 18%); Ube Industries) Y wt%
Leveling agent (FZ2105; Toray Dow Corning) 0.02wt%

The ratio (X and Y) of the carbon dispersion and the polyimide solution in the above blending was such that the surface resistance value obtained when using each dispersion was approximately 1 × 10 ¹¹ Ω / □.

(Preparation of intermediate transfer belt)
Next, a metal cylinder having an inner diameter of 100 mm and a length of 300 mm having a mirror-finished inner surface is used as a mold, and the coating liquid is uniformly cast on the inner surface of the cylinder while rotating the cylinder at 50 rpm (times / minute). And then applied as if to flow.
When the predetermined amount was completely poured and the coating film spread evenly, the number of revolutions was increased to 100 rpm, the hot air circulating dryer was introduced, and the temperature was gradually raised to 110 ° C. and heated for 60 minutes.
Furthermore, the temperature is raised and heated at 200 ° C. for 20 minutes, and the rotation is stopped, gradually cooled, taken out, put into a heating furnace (baking furnace) capable of high temperature treatment, gradually heated to 320 ° C. and heated for 60 minutes. Heat treatment (firing) was performed.
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 an intermediate transfer belt having a film thickness of 80 μm.

The surface resistance values at a total of 12 points of 3 points in the axial direction and 4 points in the circumferential direction of the obtained various belts were measured, and the average value and standard deviation of the common logarithmic values were obtained.
The standard deviation value is preferably 0.20 or less.
Above this, the variation is large, which is not preferable.

  Further, each belt was mounted on an Image MPC4500 (Ricoh), which is an electrophotographic apparatus of the type shown in FIG. 2, and 10,000 test images were continuously output to evaluate the durability of the belt.

<Measurement of surface resistance value>
The surface resistance value 10 seconds after application of 500 V was measured with Hiresta (Dia Instruments) equipped with a URS probe.
Table 2 shows the amount of carbon added to the belt obtained with various dispersions, the average value of common logarithm values of the surface resistance value, the standard deviation, and the results of the presence or absence of belt abnormality in the 10,000 sheet output durability evaluation.

次に、上記実施例で作製した分散液に用いるカーボンブラックを、ことなる製造ロットのものに変更し、同様に分散液、塗布液、ベルトを作製し、評価を行なった。
表３には、各種パス回数における分散液のカーボンブラックの粒径及び黒濃度の結果を示した。

Next, the carbon black used in the dispersion prepared in the above example was changed to that of a different production lot, and similarly, a dispersion, a coating solution, and a belt were prepared and evaluated.
Table 3 shows the results of the carbon black particle size and black density of the dispersion at various numbers of passes.

Due to the difference in carbon lot, there is a difference in the particle size and black density depending on the number of passes.
Further, even when the same particle size is reached, there is a difference in black density.
Table 4 shows the evaluation results of the belts obtained with each dispersion.

  Based on the above results, a belt is produced using a dispersion state of a dispersion of carbon black as a resistance control agent and having a black density in a spectral densitometer of a film made of the dispersion of 2.2000 to 2.5000. Thus, regardless of the production lot of carbon black, it is possible to obtain a high-quality and highly durable belt with small variations in resistance value.

(About Figure 1)
P Transfer paper L Exposure means 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 transport device 230 Revolver development unit 231Y Y developing machine 231K Bk development Machine 231C C developing machine 231M M developing machine 270 fixing device 271 and 272 fixing roller 500 intermediate transfer unit 501 intermediate transfer belt 502 toner seal member 503 charging charger 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 51 3 Toner image 514 Optical sensor 600 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 (about 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 member 26 Belt driven roller 27 Lubricant application device 50 Transfer conveyor belt 60 Secondary transfer bias roller 70 Bias roller (FIG. 3)
301 Distributed input tank A
302 Dispersing machine 303 Liquid feed pump 304 Dispersing liquid discharge tank B
(About Figure 4)
401 Dispersion liquid tank A
402 Disperser 403 Liquid circulation pump 404 Stirrer

Japanese Patent No. 4175513 Japanese Patent No. 4189915 JP 2006-348094 A JP 2006-58516 A JP 2007-204531 A JP 2008-152055 A JP2007-140055 JP2007-127825A JP 2007-248786 (closest prior art) JP 2008-9248 (closest prior art) JP2004-123774 (closest prior art)

Claims (5)

  A coating liquid prepared by a step of preparing a dispersion liquid containing at least carbon black, a resin and a solvent on the outer surface of the mold or the inner surface of the cylindrical mold, and a step of preparing a coating liquid prepared using the dispersion liquid In the method for producing an electrophotographic belt, which is formed by applying and drying and / or curing the film, and removing the mold, when the film is formed on the substrate as the dispersion A method for producing an electrophotographic belt, comprising using a dispersion having a black density of 2.200 or more and 2.500 or less in a spectral densitometer of the film.   2. The method for producing an electrophotographic belt according to claim 1, wherein the electrophotographic belt is a polyimide resin or a polyamide-imide resin.   An electrophotographic apparatus equipped with an electrophotographic belt, wherein the electrophotographic belt is manufactured by the manufacturing method according to claim 1 or 2.   An electrophotographic apparatus using an intermediate transfer belt, wherein the intermediate transfer belt is manufactured by the manufacturing method according to claim 1.   The electrophotographic apparatus according to claim 4, wherein the carbon black content of the intermediate transfer belt is 15 wt% or more and 25 wt% or less.

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