JP2010066430A - Intermediate transfer body and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intermediate transfer body which has uniform electric characteristic, and maintains stable high-quality image over a long term without causing an abnormal image such as void due to line image scattering or reverse transfer regardless of variation of a bias condition of an image forming apparatus, to provide an intermediate transfer type image forming apparatus using the intermediate transfer body, especially, suitable for full color image formation, and to provide a method for efficiently manufacturing the intermediate transfer body. <P>SOLUTION: The intermediate transfer body, to which a toner image obtained by developing a latent image formed on an image carrier with toner is transferred, includes at least a formed film layer which is formed of a coating liquid for an intermediate transfer body containing resin material or precursor thereof, and base resin obtained by dispersing acetylene alcohol and carbon black in an organic solvent. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile, and the like. The present invention relates to an intermediate transfer device and an image forming apparatus using
Furthermore, the present invention relates to a method for producing an intermediate transfer member.

Conventionally, in electrophotographic apparatuses, seamless belts have been used as members for various purposes.
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 high-speed printing, a four-tandem tandem system is used in which photoconductors 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 positional 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 fluctuations 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 is applied with a high voltage for transfer, flame retardancy is also required.
Therefore, polyimide, polyamideimide resin, and the like, which are high elastic modulus and high heat resistance resins, are mainly used.

Since the intermediate transfer belt has a function of transferring a toner image, an electrical resistance value and uniformity thereof are important.
Therefore, so that a desired value of resistance by containing carbon black or other conductive additives to the resin have been adjusted by the content-production conditions, etc., as its resistance value, 10 ⁶ - About 10 ¹² Ω · cm is required, and the variation is also required within one order within the entire belt. When it becomes non-uniform, the voltage dependency increases.
When the voltage dependency becomes large, abnormal discharge occurs in the transfer nip depending on the transfer bias condition of the apparatus, and an abnormal image such as scattering of line images or white spots due to reverse transfer occurs.
Even if the dispersion of each region is reduced by dispersion of carbon black, there is not enough margin for fluctuations in transfer conditions due to process control corresponding to environmental fluctuations, etc. Is causing.

Polyimide resin is a resin excellent in heat resistance, mechanical properties, chemical resistance, radiation resistance, etc., so various molding materials such as films and sheets, paints such as enamel for electric wires, electronic materials, flexible printed circuit boards, Widely used in applications such as heat-resistant substrates, semiconductor encapsulating materials, adhesives, and organic-inorganic composites.
Attempts have been made to achieve the purpose of improving physical properties by adding insulating fine particles to the polyimide resin.
For example, improving heat resistance and reducing the coefficient of thermal expansion (see Patent Document 1), improving slipperiness and running durability (see Patent Documents 2 and 3), printability, heat resistance, and moisture-resistant adhesion Giving is disclosed (for example, see Patent Document 4).

As a method for producing a polyimide resin, a general method is that a solvent-soluble polyamic acid is first synthesized and then heated to 300 ° C. or higher to be converted into a polyimide.
Therefore, in order to disperse the insulating fine particles in the polyimide resin, it is necessary to disperse the insulating fine particles in the polyamic acid solution.
As a dispersion method, insulating fine particles are added to a polyamic acid solution and dispersed by a dispersing machine such as a sand mill or a ball mill, or insulating fine particles are added to a polyamic acid varnish in a semi-liquid state, and three rolls are used. A direct dispersion method of kneading and dispersing is conceivable.

However, since the affinity between the insulating fine particles and the polyamic acid is very poor, when they are mixed, the insulating fine particles are aggregated and it is difficult to uniformly disperse them.
The fact that the polyamic acid solution is very viscous also makes uniform dispersion difficult.
Therefore, a method of synthesizing polyamic acid in an insulating fine particle dispersion, that is, a method of preparing a polyamic acid solution by reacting a diamine compound and an acid anhydride compound in an organic polar solvent in which insulating fine particles are dispersed in advance is proposed. (See Patent Document 3).
However, even in this method, the agglomeration of the insulating fine particles occurs due to the strong cohesion between the insulating fine particles. The thus-aggregated insulating fine particles have a particle size of 10 μm or more and become a kind of foreign matter. For example, when formed into a film shape, the surface of the film becomes rough, the gloss is lost, and the appearance of the film is impaired. It adversely affects mechanical properties such as tensile strength and electrical properties such as electrical insulation.

Similarly, the main method of dispersing carbon black in a polyamic acid solution is as follows: (1) A method of adding carbon black to a polyamic acid solution and dispersing it with a disperser such as a sand mill or a ball mill; There are known a method in which carbon black is added to the polyamic acid varnish in this state and kneaded and dispersed with a three-roll, and (3) a method in which polyamic acid is synthesized in a carbon black dispersion.
However, in any of these methods, since the compatibility between carbon black and polyamic acid is very poor, when both are mixed, carbon black is aggregated and uniform dispersion is impossible. .
As a result, carbon black is agglomerated even in the polyimide film or coating obtained, and thus problems such as rough film surface, loss of gloss, and difficulty in controlling the electric resistance value occur.

As described above, in order to prevent the Benard cell on the surface of the coating film that occurs when the polyimide precursor solution in which conductive fine particles (for example, carbon black) are dispersed is heated to perform ring-closing imidization, a fluorosurfactant or silicone is conventionally used. It is known to mix a surfactant as a third component, but even if the surface properties of the coating are improved, the resistance uniformity is not sufficient because the aggregation of conductive fine particles occurs only by mixing. When this is loaded into an image forming apparatus, there has been a problem that transferability varies as a result.
We previously described Japanese Patent Application Laid-Open No. 2005-181753 in Patent Document 5, Japanese Patent Application Laid-Open No. 2005-181762 in Patent Document 6, Japanese Patent Application Laid-Open No. 2005-181762 in Patent Document 7, and Japanese Patent Application Laid-Open No. 2005-181765 in Patent Document 8. 1, 1, 3, 6, 8, 8-hexamethyl as an acetylene glycol surfactant for dispersing carbon black in a water-soluble resin. Although use of 5-in-4,7-di (polymethyleneoxy) ol is disclosed, these do not use a non-aqueous medium.

JP 63-172741 A JP-A-3-170548 JP-A-6-145378 Japanese Patent Laid-Open No. 1-1121364 JP 2005-181753 A JP 2005-181761 A JP 2005-181763 A JP 2005-181765 A JP-A-2005-181766 Japanese Patent Publication No.42-15637

An object of the present invention is to solve various problems in the prior art and achieve the following objects.
That is, according to the present invention, the electrical characteristics are uniform, and there is no occurrence of abnormal images such as line image scattering or white spots due to reverse transfer, regardless of fluctuations in the bias conditions of the image forming apparatus. It is an object of the present invention to provide an intermediate transfer member that can maintain a high-quality image and an intermediate transfer type image forming apparatus that uses the intermediate transfer member and is particularly suitable for full-color image formation.

  Further, the present invention provides a carbon black dispersion for forming an intermediate transfer member, which improves the compatibility between fine particles such as carbon black and polyimide or polyamideimide, and the fine particles are uniformly dispersed by being reduced in size. An object of the present invention is to provide a transfer medium coating solution and to provide an efficient method for producing an intermediate transfer body using the same.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, and as a result, an intermediate transfer member onto which a toner image obtained by developing a latent image formed on an image carrier with toner is transferred. The intermediate transfer member was found to be uniform in electric resistance of the intermediate transfer member characterized in that a solution containing acetylene alcohol and carbon black was applied and dried.

That is, the said subject is solved by following (1)-(14) of this invention.
(1) “An intermediate transfer member to which a toner image obtained by developing a latent image formed on an image carrier with toner is transferred, wherein the intermediate transfer member includes a resin material or a precursor thereof; An intermediate transfer member characterized in that it has at least a film-forming layer formed from an intermediate transfer member coating solution containing a base resin in which acetylene alcohol and carbon black are dispersed in an organic solvent, "
(2) "The intermediate transfer member according to (1) above, wherein the resin material or a precursor thereof is any one of a polyimide resin and a polyamide-imide resin, or a precursor thereof",
(3) The item (1), wherein the acetylene alcohol is represented by the following general formula (1), and R ₁ , R ₂ , and R ₃ each have 20 or less carbon atoms. Or the intermediate transfer member according to item (2) ",

（式中のＲ_１、Ｒ_２、Ｒ_３は水素原子または分岐してもよい１〜２０の炭素鎖を表わし、炭素鎖には不飽和結合を含んでいてもよい。）
（４）「アセチレンアルコールの含有量が、カーボンブラックに対して１〜１００重量％であることを特徴とする前記第（１）項乃至第（３）項のいずれかに記載の中間転写体」、
（５）「前記ベース樹脂が、ポリイミド樹脂及びポリアミドイミド樹脂のいずれかであることを特徴とする前記第（１）項乃至第（４）項のいずれかに記載の中間転写体」、
（６）「シームレスベルトであることを特徴とする前記第（１）項乃至第（５）項のいずれかに記載の中間転写体」、
（７）「樹脂材料又はその前駆体、アセチレンアルコール及びカーボンブラックを含んだカーボンブラック分散液を含む中間転写体用塗工液を用いて中間転写体を形成することを特徴とする中間転写体の製造方法」、
（８）「前記樹脂材料又はその前駆体が有機溶媒液の溶液であり、該有機溶媒液溶液に、前記カーボンブラック分散液が分散される段階を有することを特徴とする前記第（７）項に記載の中間転写体の製造方法」、
（９）「前記アセチレンアルコールが、下記一般式（１）で表わされるアセチレンアルコールのアルキル基（Ｒ_１、Ｒ_２、Ｒ_３）の炭素数がそれぞれ２０以下であることを特徴とする前記第（７）項又は第（８）項に記載の中間転写体の製造方法」、

(R ₁ , R ₂ and R ₃ in the formula represent a hydrogen atom or 1 to 20 carbon chains which may be branched, and the carbon chain may contain an unsaturated bond.)
(4) “Intermediate transfer member according to any one of items (1) to (3), wherein the content of acetylene alcohol is 1 to 100% by weight with respect to carbon black” ,
(5) "Intermediate transfer member according to any one of (1) to (4), wherein the base resin is any one of a polyimide resin and a polyamideimide resin",
(6) “Intermediate transfer member according to any one of (1) to (5) above, which is a seamless belt”,
(7) An intermediate transfer member characterized in that an intermediate transfer member is formed using a coating solution for an intermediate transfer member including a carbon black dispersion containing a resin material or a precursor thereof, acetylene alcohol and carbon black. Production method",
(8) The item (7), wherein the resin material or a precursor thereof is a solution of an organic solvent solution, and the carbon black dispersion is dispersed in the organic solvent solution. Production method of intermediate transfer member according to
(9) “The acetylene alcohol is characterized in that the carbon number of the alkyl group (R ₁ , R ₂ , R ₃ ) of the acetylene alcohol represented by the following general formula (1) is 20 or less, respectively ( 7) or method for producing an intermediate transfer member according to item (8) ",

（式中のＲ_１、Ｒ_２、Ｒ_３は水素原子または分岐してもよい１〜２０の炭素鎖を表わし、炭素鎖には不飽和結合を含んでいてもよい。）
（１０）「前記中間転写体用塗工液が、アセチレンアルコールとカーボンブラックの他にさらにベース樹脂又はその前駆体を分散してなるカーボンブラック分散液を前記樹脂材料又はその前駆体の液に分散したものであり、該ベース樹脂が、ポリイミド樹脂及びポリアミドイミド樹脂のいずれか、又はそれらの前駆体であることを特徴とする前記第（７）項又は第（８）項に記載の中間転写体の製造方法」、
（１１）「前記カーボンブラック分散液中に、前記樹脂材料又はその前駆体と同じ樹脂を含有することを特徴とする前記第（９）項に記載の中間転写体の製造方法」、
（１２）「前記カーボンブラック分散液中におけるカーボンブラックの体積平均粒径が、１０〜３００ｎｍであることを特徴とする前記第（７）項乃至第（１０）項のいずれかに記載の中間転写体の製造方法」、
（１３）「潜像が形成され、トナー像を担持可能な像担持体と、該像担持体上に形成された潜像をトナーで現像する現像手段と、該現像手段により現像されたトナー像が一次転写される中間転写体と、該中間転写体上に担持されたトナー像を記録媒体に二次転写する転写手段とを有してなり、前記中間転写体が前記第（１）項乃至第（６）項のいずれかに記載の中間転写体であることを特徴とする画像形成装置」、
（１４）「画像形成装置がフルカラー画像形成装置であって、各色の現像手段を有する複数の潜像担持体を直列に配置してなることを特徴とする前記第（１３）項に記載の画像形成装置」。

(R ₁ , R ₂ and R ₃ in the formula represent a hydrogen atom or 1 to 20 carbon chains which may be branched, and the carbon chain may contain an unsaturated bond.)
(10) “The coating liquid for the intermediate transfer member disperses a carbon black dispersion obtained by further dispersing a base resin or a precursor thereof in addition to acetylene alcohol and carbon black in the resin material or a precursor thereof The intermediate transfer member according to (7) or (8), wherein the base resin is any one of a polyimide resin and a polyamideimide resin, or a precursor thereof. Manufacturing method ",
(11) "The method for producing an intermediate transfer member according to (9) above, wherein the carbon black dispersion contains the same resin as the resin material or a precursor thereof",
(12) The intermediate transfer according to any one of (7) to (10), wherein the volume average particle diameter of carbon black in the carbon black dispersion is 10 to 300 nm. Body manufacturing method ",
(13) “An image carrier on which a latent image is formed and capable of carrying a toner image, a developing unit for developing the latent image formed on the image carrier with toner, and a toner image developed by the developing unit And an intermediate transfer member on which the toner image carried on the intermediate transfer member is secondarily transferred to a recording medium. The intermediate transfer member is the first to the first items. An image forming apparatus characterized in that it is an intermediate transfer member according to any one of Items (6), "
(14) The image forming apparatus according to item (13), wherein the image forming apparatus is a full-color image forming apparatus, and a plurality of latent image carriers having developing units for respective colors are arranged in series. Forming equipment ".

According to the present invention, it is possible to reduce the variation in resistance at an arbitrary position of the obtained belt and to reduce the voltage dependency.
Further, according to the present invention, the resistance uniformity can be further improved and the voltage dependency can be further reduced.
Furthermore, according to the present invention, an intermediate transfer member excellent in heat resistance, chemical resistance and radiation resistance can be obtained.
Furthermore, according to the present invention, a toner image can be efficiently transferred to paper.
Furthermore, according to the present invention, it is possible to efficiently produce an intermediate transfer member using a carbon black dispersion liquid in which carbon black is reduced in size and uniformly dispersed.
Furthermore, according to the present invention, an intermediate transfer member excellent in heat resistance, chemical resistance and radiation resistance can be produced efficiently.
Furthermore, according to the present invention, it is possible to produce an intermediate transfer body in which the strength of the prepared intermediate transfer body does not impair the original strength of the polyimide resin and the polyamideimide resin as the base resin.
Furthermore, according to the present invention, it is possible to perform high-quality image formation that does not generate an abnormal image over a long period of time.
The intermediate transfer member in the present invention is not limited to a tandem type image forming apparatus. In addition, for example, a transfer drum system and a transfer roll system are also applicable.
Furthermore, according to the present invention, it is possible to provide an image forming apparatus suitable for full color image formation adapted to higher speed while maintaining quality.

In the intermediate transfer member of the present invention, a toner image obtained by developing a latent image formed on an image carrier with toner is transferred, and the intermediate transfer member contains at least carbon black containing acetylene alcohol. It contains a base resin and, if necessary, other components.
In the method for producing an intermediate transfer member of the present invention, an intermediate transfer member is formed using a coating solution for an intermediate transfer member including a carbon black dispersion containing carbon black containing acetylene alcohol.

Hereinafter, the details of the method for producing an intermediate transfer member of the present invention will be clarified through the description of the intermediate transfer member of the present invention.
As described above, the intermediate transfer member of the present invention is not particularly limited as long as it contains at least carbon black containing acetylene alcohol, and can be appropriately selected according to the purpose. The thing suitably provided with the other structure suitably selected as needed is mentioned. Among these, those provided with a surface layer are particularly preferable.
There is no restriction | limiting in particular as a shape of the said intermediate transfer body, According to the objective, it can select suitably, For example, a drum shape (cylindrical shape), an endless belt shape, etc. are mentioned.
The structure of the intermediate transfer member is not particularly limited and can be appropriately selected according to the purpose. For example, a single layer structure including only the surface layer, a multilayer structure including the surface layer on a substrate, or Examples include a structure in which the surface or back surface of the single layer structure is subjected to processing such as polishing to adjust the properties of the front and back surfaces. Among these, a single layer structure including only the surface layer is particularly preferable.
Therefore, in the intermediate transfer member of the present invention, it is preferable that the surface layer contains at least carbon black containing acetylene alcohol, and further contains a base resin and, if necessary, other components. .

<Acetylene alcohol>
The acetylene alcohol is a nonionic surfactant having a hydroxyl group (—OH) on one of the carbon atoms next to the acetylene group (—C≡C—), and is represented by the following general formula (1). A compound having one hydroxyl group at each of the carbon atoms adjacent to the acetylene group is called acetylene glycol and is represented by the following general formula (2).
Both are used in water-based materials in various directions as antifoaming agents, wetting agents, and dispersing agents in liquid materials using aqueous media.

（式中のＲ_１、Ｒ_２、Ｒ_３は水素原子または分岐してもよい炭素鎖を表わし、炭素鎖には不飽和結合を含んでいてもよい。）

(Wherein R ₁ , R ₂ and R ₃ represent a hydrogen atom or a carbon chain which may be branched, and the carbon chain may contain an unsaturated bond.)

（式中のＲ_４、Ｒ_５、Ｒ_６は分岐してもよい炭素鎖を表わし、炭素鎖には不飽和結合を含んでいてもよい。）
これらの中でもアセチレンアルコールが好適である。

(R ₄ , R ₅ and R ₆ in the formula represent a carbon chain which may be branched, and the carbon chain may contain an unsaturated bond.)
Of these, acetylene alcohol is preferred.

The acetylene alcohol has a great effect on the dispersion of carbon black in the resin material or the precursor thereof in the present invention. Among them, R ₁ , R ₂ and R _{3 in} the general formula (1) each have 20 or less carbon atoms. It is particularly preferable from the viewpoint of being easily adsorbed on the surface of carbon black, suppressing aggregation between particles, and having a high effect as a dispersant, and more preferably having 0 to 10 carbon atoms.
When any one of R ₁ , R ₂ , and R ₃ has 21 or more carbon atoms, an increase in the particle size of the carbon black is observed when a polyamic acid is added to the carbon black dispersion to prepare a coating solution. Therefore, the effect as a dispersant is halved.
Examples of R include a hydrogen atom, a single bond, an alkylene group, and an aryl group.

Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group.
Examples of the aryl group include a phenyl group and a tolyl group.

  Acetylene glycol is also used as a dispersant in non-aqueous materials, but its affinity with carbon black is poor compared to acetylene alcohol, so it is not only difficult to finely disperse carbon black, but also when preparing a coating liquid. Since carbon black is very agglomerated, the stability is poor. From the above, it is preferable to use acetylene alcohol.

Examples of the acetylene alcohol include 3-butyn-2-ol, 1-octin-3-ol, 1,1,3-triphenyl-2-propyne-1-ol, 1,1-diphenyl-2-propyne-1 -Ol, 1-heptin-3-ol, 1-hexyn-3-ol, 1-octyn-3-ol, 1-pentyn-3-ol, 1-phenyl-2-propyn-1-ol, 2,2 , 8,8-tetramethyl-3,6-nonadiin-5-ol, 2-butyn-1-ol, 2-decyn-1-ol, 2-heptin-1-ol, 2-hexyn-1-ol, 2-methyl-4-phenyl-3-butyn-2-ol, 2-pentyn-1-ol, 2-propyn-1-ol, 3,4-dimethyl-1-pentyn-3-ol, 3,5- Dimethyl-1-hexyne -Ol, 3,6-dimethyl-1-heptin-3-ol, 3-ethyl-1-heptin-3-ol, 3-ethyl-1-pentyn-3-ol, 3-methyl-1-butyne-3 -Ol, 3-methyl-1-penten-4-in-3-ol, 3-methyl-1-pentyn-3-ol, 3-phenyl-2-propyn-1-ol, 4-ethyl-1-octyne -3-ol, 5-methyl-1-hexyn-3-ol, and the like.
The acetylene alcohol can be synthesized by using an addition reaction between a acetylene Grignard reagent or a lithium reagent and a carbonyl compound.

The carbon black is not particularly limited and may be appropriately selected depending on the intended purpose. However, acidic carbon is preferred, and specifically, ketjen black, furnace black, acetylene black, thermal black, gas Black etc. are mentioned. The carbon black preferably contains amounts of 1 × 10 ⁸ to 1 × 10 ¹³ Ω / □ in surface resistance and 1 × 10 ⁶ to 1 × 10 ¹² Ω · cm in volume resistance. Therefore, it is preferable to select a film that can be achieved with an addition amount that is not brittle and does not easily break.
Carbon black and acetylene alcohol are sufficiently dispersed in a polar organic solvent (for example, N-methyl-2-pyrrolidone), and then mixed with a polyimide precursor solution or a polyamideimide precursor solution to obtain a coating solution. Prepare.

The amount of the acetylene alcohol added is preferably 1 to 100% by weight (solid content), more preferably 5 to 75% by weight (solid content) with respect to the carbon black.
If the addition amount is less than 1% by weight, the effect as a dispersant is not sufficiently exhibited, so that carbon black cannot be finely dispersed. The increase is increased, and the effect as a dispersant is halved.

Furthermore, in order to more effectively suppress the shock aggregation of carbon black when the carbon black dispersion is mixed with the polyimide or polyamideimide precursor solution, a small amount of a base resin described later is further added and dispersed. With more favorable results.
The amount of the base resin added is preferably 0.05 to 50% by weight (solid content) and more preferably 0.1 to 20% by weight (solid content) with respect to the carbon black.
If the amount of the base resin added exceeds 50% by weight, the viscosity of the carbon black dispersion liquid becomes considerably high, which is not preferable because the dispersibility of the carbon black deteriorates.

The content of the carbon black in the intermediate transfer member is preferably 5 to 35% by weight, and more preferably 15 to 25% by weight.
When the content is less than 5% by weight, the effect of adding carbon black may not be sufficiently obtained. Sometimes.

Then, a dispersion | distribution process is demonstrated.
The disperser used in the present invention is not particularly limited as long as it is a commonly used disperser, and can be appropriately selected according to the purpose. Examples thereof include a ball mill, a roll mill, and a sand mill.
Among these, a high-speed sand mill is preferable, and examples thereof include a super mill, a sand grinder, a bead mill, an agitator mill, a glen mill, a dyno mill, a pearl mill, and a cobol mill (all are trade names).

The primary particle diameter of the carbon black is 10 nm to 1 μm, but when mixed in the dispersion, aggregation may occur when the carbon black is dispersed.
The carbon black in the carbon black dispersion liquid preferably has a volume average particle size of 10 to 300 nm, more preferably 50 to 250 nm.
The volume average particle size of carbon black treated with acetylene alcohol in the intermediate transfer member coating solution is preferably 10 to 300 nm, and more preferably 50 to 250 nm.
If the volume average particle size of the carbon black exceeds 300 nm, the carbon black having a large particle size present in the surface layer during the production process of the intermediate transfer member becomes a protrusion on the belt surface, resulting in deterioration of surface accuracy and non-uniform resistance. Furthermore, it may cause a decrease in resistance due to an electrical load of the semiconductive belt.
On the other hand, if the volume average particle size of the carbon black is less than 10 nm, the amount added is too large to obtain a desired resistance value, and the mechanical properties of the intermediate transfer member may be deteriorated.
Here, the volume average particle diameter of the carbon black is, for example, a sample obtained by diluting the obtained carbon black dispersion liquid and the intermediate transfer body coating liquid with a dispersion solvent, using a particle size analyzer (for example, manufactured by Nikkiso Co., Ltd.). , Microtrack UPA).

<Base resin>
As the base resin, either a polyimide resin or a polyamide-imide resin (and therefore a precursor thereof in the dispersion stage) is suitable. The base resin may be added to the carbon black dispersion as described above.
-Polyimide resin-
The polyimide resin is a polyamic acid (polyimide precursor) obtained by reacting a generally known polyvalent carboxylic acid anhydride or a derivative thereof such as an aromatic polyvalent carboxylic acid anhydride or a derivative thereof with an aromatic diamine. ).
This polyimide resin is insoluble in solvents and the like due to its rigid main chain structure and has an infusible property. Therefore, the polyimide resin can be used as an organic solvent first from the polycarboxylic anhydride and aromatic diamine. A soluble polyimide precursor (polyamic acid or polyamic acid) is synthesized.
At this stage, molding is performed by various methods, and then the polyamic acid is dehydrated by heating or a chemical method to be cyclized (imidized) to obtain polyimide. The outline of this reaction is shown in the following reaction formula.

（ただし、前記反応式中、Ａｒ^１は、少なくとも１つの炭素６員環を含む４価の芳香族残基を表わす。Ａｒ^２は、少なくとも１つの炭素６員環を含む２価の芳香族残基を表わす。）

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

Examples of the polyvalent carboxylic acid anhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, and 2,2 ′, 3,3′-benzophenone tetracarboxylic acid. Acid 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-di Carboxyphenyl -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 can be mentioned.
In addition, for example, ethylenetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride and the like can be mentioned.
These may be used individually by 1 type and may use 2 or more types together.

Examples of the aromatic diamine to be reacted with the polyvalent carboxylic acid anhydride include m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 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-aminophenyl) sulfone, bis (4 -Aminophenyl) sulfone, 3,3′-di Aminobenzophenone, 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, -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-amino Enoxy) 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′-bis [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 may be used individually by 1 type and may use 2 or more types together. Among these, it is particularly preferable to use 4,4′-diaminodiphenyl ether in order to effectively express the physical properties of the intermediate transfer member.

A polyimide precursor (polyamic acid) can be obtained by polymerizing the polyvalent carboxylic acid anhydride component and the diamine component in an organic polar solvent using substantially equimolar amounts.
Hereafter, the manufacturing method of a polyamic acid is demonstrated concretely.

As an example of producing the polyimide precursor, first, one or more kinds of diamines are dissolved in the above organic solvent or dispersed in a slurry state in an inert gas atmosphere such as argon or nitrogen.
When at least one of the polyvalent carboxylic acid anhydrides or derivatives thereof described above 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 opens with heat generation. A cyclopolyaddition reaction occurs, and the viscosity of the solution is rapidly increased, and a high molecular weight polyamic acid solution is obtained. In this case, the reaction temperature is usually preferably from −20 ° C. to 100 ° C., and more preferably controlled to 60 ° C. or less.
The reaction time is preferably 30 minutes to 12 hours.

The above is an example. Contrary to the addition procedure in the reaction, the polycarboxylic acid anhydride or derivative thereof may be first dissolved or diffused in an organic solvent, and the diamine may be added to this solution. .
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 tetracarboxylic dianhydride and the aromatic diamine may be simultaneously added to an organic polar solvent for reaction.

  As described above, the polyamic acid is uniformly dissolved in the organic polar solvent by polymerizing the polyvalent carboxylic acid anhydride or derivative thereof and the aromatic diamine component in an approximately equimolar amount of the organic polar solvent. In this state, a polyimide precursor solution is obtained.

There is no restriction | limiting in particular as an organic polar solvent used for the polymerization reaction of the said polyamic acid, Although it can select suitably according to the objective, For example, sulfoxide type | system | group solvents, such as a dimethyl sulfoxide and diethyl sulfoxide; N, N- Formamide solvents such as dimethylformamide and N, N-diethylformamide; acetamide solvents such as N, N-dimethylacetamide and N, N-diethylacetamide; N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone Pyrrolidone solvents; phenol solvents such as phenol, o-, m-, or p-cresol, xylenol, halogenated phenol, catechol; ether solvents such as tetrahydrofuran, dioxane, dioxolane; alcohols such as methanol, ethanol, butanol System solvent; Cellosolve solvents such as Ruserosorubu, hexamethylphosphoramide, .gamma.-butyrolactone, and the like.
These may be used individually by 1 type and may use 2 or more types together. Among these, N, N-dimethylacetamide and N-methyl-2-pyrrolidone are particularly preferable from the viewpoint of solubility of polyamic acid.

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, Since the method is more complicated and costly than the heating method of 1), the method of (1) is often used.
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.
Here, the progress of imidization (the 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 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), Represented.

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。
（１）イミドの特性吸収の１つである７２５ｃｍ^−１（イミド環Ｃ＝Ｏ基の変角振動帯）と、ベンゼン環の特性吸収１，０１５ｃｍ^−１との吸光度比
（２）イミドの特性吸収の１つである１，３８０ｃｍ^−１（イミド環Ｃ−Ｎ基の変角振動帯）と、ベンゼン環の特性吸収１，５００ｃｍ^−１との吸光度比
（３）イミドの特性吸収の１つである１，７２０ｃｍ^−１（イミド環Ｃ＝Ｏ基の変角振動帯）と、ベンゼン環の特性吸収１，５００ｃｍ^−１との吸光度比
（４）イミドの特性吸収の１つである１，７２０ｃｍ^−１とアミド基の特性吸収１，６７０ｃｍ^−１（アミド基Ｎ−Ｈ変角振動とＣ−Ｎ伸縮振動の間の相互作用）との吸光度比
また、３０００〜３３００ｃｍ^−１にかけてのアミド基由来の多重吸収帯が消失していることを確認すれば更にイミド化完結の信頼性は高まる。

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 Furthermore enhanced reliability of imidization complete if.

-Polyamideimide resin-
The polyamideimide resin 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 has a generally known structure. be able to.
In general, 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. A known method for producing by reacting in a solvent is known (for example, see Japanese Examined Patent Publication No. 42-15637).

Further, 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 Examined Patent Publication 44-44). No. 19274) is 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, a compound represented by the following formula (2) or a compound represented by the following formula (3) is used. Can do.

（ただし、前記式（２）及び式（３）中、Ｘはハロゲン元素を示し、Ｙは−ＣＨ_２−、−ＣＯ−、−ＳＯ_２−又はＯ−を示す。）

(However, in the formula (2) and (3), X represents a halogen element, Y is _{-CH 2 -, - CO -,} - SO 2 - or an O-.)

In the formulas (2) and (3), the halogen element is preferably a chlorine atom, and examples of the derivative include terephthalic acid, isophthalic acid, 4,4′biphenyldicarboxylic acid, and 4,4′biphenyletherdicarboxylic acid. 4,4′biphenylsulfone dicarboxylic acid, 4,4′benzophenone dicarboxylic acid, pyromellitic acid, trimellitic acid, 3,3 ′, 4,4′benzophenone tetracarboxylic acid, 3,3 ′, 4,4′biphenyl Sulfonetetracarboxylic acid, 3,3 ′, 4,4′biphenyltetracarboxylic acid, adipic acid, sebacic acid, maleic acid, fumaric acid, dimer acid, stilbene dicarboxylic acid, 1,4 cyclohexane dicarboxylic acid, 1,2 cyclohexane dicarboxylic acid Examples thereof include acid chlorides of polyvalent carboxylic acids such as acids.
These may be used individually by 1 type and may use 2 or more types together.

On the other hand, the diamine is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include aromatic diamines, aliphatic diamines, and alicyclic diamines. Among these, aromatic diamines include Particularly preferred.
Examples of the aromatic diamine include m-phenylenediamine, p-phenylenediamine, oxydianiline, methylenediamine, hexafluoroisopropylidenediamine, diamino-m-xylylene, diamino-p-xylylene, and 1,4-naphthalenediamine. 1,5-naphthalenediamine, 2,6-naphthalenediamine, 2,7-naphthalenediamine, 2,2′-bis- (4-aminophenyl) propane, 2,2′-bis- (4-aminophenyl) Hexafluoropropane, 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 ester Ether, isopropylidenedianiline, 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 Hexafluoropropane, 4,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfide, and the like.
These may be used individually by 1 type and may use 2 or more types together.

  Further, as the diamine, a siloxane compound having amino groups at both ends, for example, 1,3-bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane, α, ω-bis (3 -Aminopropyl) 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 1,3-bis (3- (3-aminophenoxy) propyl) -1,1,3,3-tetramethyldisiloxane, α, ω-bis (3- (3-aminophenoxy) If propyl) 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, as in the case of the production of the polyimide resin, the above-described trivalent carboxylic acid derivative halide and diamine having an acid anhydride group Is dissolved in an organic polar solvent and then reacted at a low temperature (0 to 30 ° C.) to obtain a polyamideimide precursor (polyamide-amic acid).

The organic polar solvent is the same as the polyimide, and a formamide solvent (for example, sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, N, N-dimethylformamide, N, N-diethylformamide, etc.), an acetamide solvent (Eg, N, N-dimethylacetamide, N, N-diethylacetamide, etc.), pyrrolidone solvents (eg, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, etc.), phenol solvents (eg, phenol) , O-, m-, or p-cresol, xylenol, halogenated phenol, catechol, etc.), ether solvents (eg, tetrahydrofuran, dioxane, dioxolane, etc.), alcohol solvents (eg, methanol, ethanol, butanol, etc.), Cellosolve Medium (e.g., butyl cellosolve, etc.), hexamethylphosphoramide, γ- butyrolactone.
These may be used individually by 1 type and may use 2 or more types together. Among these, N, N-dimethylacetamide and N-methyl-2-pyrrolidone are particularly preferable from the viewpoint of solubility of polyamic acid.

  After the polyamide / polyamic acid solution obtained as described above is applied to a support (molding mold), the polyamic acid is converted to polyimide (imidation) by treatment such as heating.

Examples of the imidization method include a method of dehydrating and ring-closing by heat treatment, and a method of chemically ring-closing using a dehydrating and ring-closing catalyst.
When dehydrating and ring-closing by heat treatment, for example, the reaction temperature is preferably 150 to 400 ° C, and more preferably 180 to 350 ° C.
The heat treatment time is preferably 30 seconds to 10 hours, and more preferably 5 minutes to 5 hours.
Moreover, when using a dehydration ring closure catalyst, 0-180 degreeC of reaction temperature is preferable and 10-80 degreeC is more preferable.
The reaction time is preferably several tens of minutes to several days, more preferably 2 hours 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 Examples of the trivalent carboxylic acid derivative having an acid anhydride group used in the isocyanate method include a compound represented by the following formula (IV) or a compound represented by the following formula (V). Can be used.

（ただし、前記式（ＩＶ）中、Ｒは水素原子、炭素数１〜１０のアルキル基、又はフェニル基を示す。）

(However, in said formula (IV), R shows a hydrogen atom, a C1-C10 alkyl group, or a phenyl group.)

（ただし、前記式（Ｖ）中、Ｒは水素原子、炭素数１〜１０のアルキル基、又はフェニル基を表わす。Ｙは−ＣＨ_２−、−ＣＯ−、−ＳＯ_２−、又はＯ−を表わす。）

(However, in the formula (V), R .Y is _-CH 2 represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group -, - CO -, - SO 2 -, or O-; Represents.)

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

As one aromatic polyisocyanate used for the synthesis of the polyamideimide, 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 - dimethoxy-biphenyl-4,4'-diisocyanate, 2,2'-dimethoxy-biphenyl-4,4'-diisocyanate, naphthalene-1,5-diisocyanate, and the like 2,6-diisocyanate.
These may be used individually by 1 type and may use 2 or more types together.

  Further, if necessary, as a part of the aromatic polyisocyanate, for example, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, transcyclohexane-1, Aliphatic, alicyclic isocyanates such as 4-diisocyanate, hydrogenated m-xylylene diisocyanate, and lysine diisocyanate, and trifunctional or higher polyisocyanates can also be used.

A solution containing a polyamideimide precursor obtained by dissolving a trivalent carboxylic acid derivative having each acid anhydride group and an aromatic polyisocyanate in an organic polar solvent and applying the solution is applied to a substrate (or mold). Then, the heat treatment is performed to convert the polyamideimide precursor to the polyamideimide.
Upon conversion to polyamideimide by this method, polyamideimide is generated without generating a carbonic acid (generally generating carbon dioxide).

  Here, an example of polyamide imidation when trimellitic anhydride and aromatic isocyanate are used is shown in the following reaction formula (VI).

（ただし、前記反応式（ＶＩ）中、Ａｒは芳香族基を示す。）

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

The polyimide and polyamideimide shown in the above reaction formula (VI) 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.

The polyimide precursor solution (polyamic acid solution) can be synthesized as described above. For convenience, a so-called polyimide varnish in which the polyamic acid composition is dissolved in an organic solvent is used. You can also obtain and use what is marketed.
Examples of such commercially available products include Trenys (manufactured by Toray Industries, Inc.), U-Varnish (manufactured by Ube Industries, Ltd.), Rika Coat (manufactured by Nippon Nippon Chemical Co., Ltd.), Optmer (manufactured by JSR), SE812 (manufactured by Nissan Chemical Industries, Ltd.). CRC8000 (manufactured by Sumitomo Bakelite Co., Ltd.) and the like are typical examples.
In this way, a filler is mixed with the polyamic acid solution synthesized or obtained as necessary, and dispersed 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.

  Next, centrifugal molding, which is one of the most preferable methods, will be described as a method for producing a seamless belt using a coating liquid containing the polyimide precursor or polyamideimide precursor. In addition, the following description is an example and conditions etc. are not limited to this.

The centrifugal molding is composed of a cylindrical rotating body. While slowly rotating the cylindrical rotating body, the coating liquid is applied uniformly over the entire inner surface of the cylinder, and cast ( A coating film is formed).
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 and 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 (baking furnace) capable of high-temperature treatment, heated in steps, and finally heated at about 250 to 450 ° C. ( Calcination) and sufficiently imidization or polyamide-imidization of the polyimide precursor or polyamide-imide precursor.
After completion of imidization or the like, the film is slowly cooled to peel the thin film from the mold.
A seamless belt is thus formed. In addition, it is preferable to previously form a mold release agent or a mold release layer on the mold so that the mold can be easily peeled off.

  The dispersion of the carbon black and the high-resistance metal oxide in the polyimide precursor solution is preferably performed using a disperser such as a bead mill, a ball mill, a nanomizer, a paint shaker, or a jet mill.

  As described above, the intermediate transfer member of the present invention has uniform electrical characteristics, and abnormal images such as line image scattering and white spots due to reverse transfer occur regardless of bias condition fluctuations of the image forming apparatus. Since it is possible to maintain a stable and high-quality image over a long period of time, it can be used for various coatings. Among these, it is particularly preferably used for an image forming apparatus described below.

<Image forming apparatus>
The image forming apparatus of the present invention includes an image carrier that can form a latent image and can carry a toner image, a developing unit that develops the latent image formed on the image carrier with toner, and a developing unit that develops the latent image. An intermediate transfer body on which the toner image is primarily transferred, and a transfer means for secondary transfer of the toner image carried on the intermediate transfer body to a recording medium, and further appropriately selected as necessary It has other means, for example, static elimination means, cleaning means, recycling means, control means and the like.
In this case, it is preferable that the image forming apparatus is a full-color image forming apparatus in which a plurality of latent image carriers having developing units for respective colors are arranged in series.

<Image forming method>
Further, the image forming method in the image forming apparatus of the present invention includes at least an electrostatic latent image forming step, a developing step, a transfer step, and a fixing step, and further other steps appropriately selected as necessary. For example, a static elimination process, a cleaning process, a recycling process, a control process, and the like are included.
The image forming method can be preferably implemented by the image forming apparatus, the electrostatic latent image forming step can be performed by the electrostatic latent image forming unit, and the developing step can be performed by the developing unit. The transfer step can be performed by the transfer unit, the fixing step can be performed by the fixing unit, and the other steps can be performed by the other unit.

-Electrostatic latent image forming step and electrostatic latent image forming means-
The electrostatic latent image forming step is a step of forming an electrostatic latent image on the image carrier.
The image carrier is not particularly limited with respect to the material, shape, structure, size, etc., and can be appropriately selected from known ones. The shape is preferably a drum shape, Examples of the material include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors such as polysilane and phthalopolymethine. Among these, an amorphous silicon inorganic photoreceptor and an organic photoreceptor using a phthalocyanine-based polymethine pigment are preferably used from the viewpoint of long life.

The formation of the electrostatic latent image can be performed, for example, by uniformly charging the surface of the image carrier and then exposing it imagewise, and can be performed by the electrostatic latent image forming means. .
The electrostatic latent image forming unit includes, for example, at least a charger that uniformly charges the surface of the image carrier and an exposure unit that exposes the surface of the image carrier imagewise.

The charging can be performed, for example, by applying a voltage to the surface of the image carrier using the charger.
The charger is not particularly limited and may be appropriately selected depending on the purpose. For example, a known contact charging device including a conductive or semiconductive roll, brush, film, rubber blade, etc. And non-contact chargers using corona discharge such as corotrons and corotrons.

The exposure can be performed, for example, by exposing the surface of the image carrier imagewise using the exposure device.
The exposure device is not particularly limited as long as it can perform image-like exposure on the surface of the image carrier charged by the charger, and can be appropriately selected according to the purpose. Examples include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system.
In addition, you may employ | adopt the light back system which performs imagewise exposure from the back surface side of the said image carrier.

-Development process and development means-
The developing step is a step of developing the electrostatic latent image using the developer to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using the developer, and can be performed by the developing unit.

The developing unit is not particularly limited as long as it can be developed using, for example, the developer, and can be appropriately selected from known ones. For example, the developer is accommodated and the electrostatic latent is stored. Preferable examples include those having at least a developing unit capable of applying the developer to the image in a contact or non-contact manner.
The developing unit may be a dry developing type, a wet developing type, a single color developing unit, or a multi-color developing unit. For example, a toner having a stirrer for charging the toner or the developer by frictional stirring and a rotatable magnet roller is preferable.
In the developing device, for example, the toner and the carrier are mixed and agitated, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. .
Since the magnet roller is disposed in the vicinity of the image bearing member (photosensitive member), a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is caused by the electric attractive force. It moves to the surface of the image carrier (photoconductor). As a result, the electrostatic latent image is developed with the toner, and a visible image is formed with the toner on the surface of the image carrier (photoconductor).
The developer accommodated in the developing device is the developer, but the developer may be a one-component developer or a two-component developer.

-Transfer process and transfer means-
The transfer step is a step of transferring the visible image to a recording medium. After the primary image is transferred onto the intermediate transfer member using the intermediate transfer member of the present invention, the visible image is transferred to the recording medium. A mode of secondary transfer onto the recording medium is preferable, and a primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer member using two or more colors, preferably full color toner as the toner. And a secondary transfer step of transferring the composite transfer image onto a recording medium is more preferable.

The transfer can be performed, for example, by charging the image carrier (photosensitive member) with the transfer charger using the visible image, and can be performed by the transfer unit.
The transfer means includes a primary transfer means for transferring a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer means for transferring the composite transfer image onto a recording medium. Embodiments are preferred.
Suitable examples of the intermediate transfer member include an intermediate transfer belt that is the intermediate transfer member of the present invention.
The transfer means (the primary transfer means and the secondary transfer means) includes at least a transfer device that peels and charges the visible image formed on the image carrier (photoconductor) to the recording medium side. It is preferable to have. There may be one transfer means or two or more transfer means.
Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device. The recording medium is not particularly limited and can be appropriately selected from known recording media (recording paper).

The fixing step is a step of fixing the visible image transferred to the recording medium using a fixing device, and may be performed each time the toner of each color is transferred to the recording medium, or for the toner of each color. You may perform this simultaneously in the state which laminated | stacked this.
There is no restriction | limiting in particular as said fixing device, Although it can select suitably according to the objective, A well-known heating-pressing means is suitable.

Examples of the heating and pressing means include a combination of a heating roller and a pressure roller, a combination of a heating roller, a pressure roller, and an endless belt.
The heating in the heating and pressing means is usually preferably 80 ° C to 200 ° C.
In the present invention, for example, a known optical fixing device may be used together with or in place of the fixing step and the fixing unit depending on the purpose.

The neutralization step is a step of performing neutralization by applying a neutralization bias to the image carrier, and can be suitably performed by a neutralization unit.
The neutralization means is not particularly limited and may be appropriately selected from known neutralizers as long as it can apply a neutralization bias to the image carrier. It is done.

The cleaning step is a step of removing the electrophotographic toner remaining on the image carrier and can be suitably performed by a cleaning unit.
The cleaning means is not particularly limited, and may be selected from known cleaners as long as it can remove the electrophotographic toner remaining on the image carrier. For example, a magnetic brush cleaner, Suitable examples include electrostatic brush cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, web cleaners, and the like.

The recycling step is a step of recycling the electrophotographic toner removed in the cleaning step to the developing unit, and can be suitably performed by the recycling unit.
There is no restriction | limiting in particular as said recycling means, A well-known conveyance means etc. are mentioned.
The control means is a process for controlling the steps, and can be suitably performed by the control means.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

  Here, the seamless 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.

FIG. 1 is a diagram showing a schematic configuration of a main part of an image forming apparatus equipped with a belt member of the present invention.
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 drive 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), and a cleaning counter roller, which are primary transfer charge applying units. (511) and the feedback current detection roller (512).
Each roller is formed of a conductive material, and each roller other than the primary transfer bias roller (507) is grounded.
The primary transfer bias roller (507) has a transfer bias controlled to a predetermined current or voltage according to the number of superimposed toner images by a primary transfer power source (801) controlled by a constant current or a constant voltage. 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).
As the intermediate transfer belt (501) as the belt member, a seamless belt containing carbon black containing acetylene alcohol of the present invention is used, whereby durability is improved and 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 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 bias roller (605) and the intermediate transfer belt (501) of the portion stretched around 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.

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

  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 as indicated by an arrow by a belt driving roller (508).
Along with the rotation of the intermediate transfer belt (501), the primary transfer of the Bk toner image, the C toner image, the M toner image, and the Y toner image is performed by the transfer bias by the voltage applied to the primary transfer bias roller (507). Finally, the 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 primarily transferred onto the outer peripheral surface of the intermediate transfer belt (501) rotating at a constant speed while being in contact with the photosensitive drum (200). Is done. 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). The
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 operations of reading color image data, forming an electrostatic latent image, and developing 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 between the secondary transfer counter rollers (510) and the secondary transfer bias roller (605) form a nip on the secondary transfer portion. 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 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.

Thus, 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 images are transferred onto the transfer paper (P) at once (secondary transfer).
The transfer paper (P) is transported along the transfer paper guide plate (601) and passes through a portion facing the transfer paper neutralization charger (606) including a static elimination needle disposed on the downstream side 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).
Further, residual toner remaining on the outer peripheral surface of the intermediate transfer belt (501) after the toner image is secondarily transferred to the transfer paper (P) is cleaned by the belt cleaning blade (504).
The belt cleaning blade (504) is configured to 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 (503) contacting and separating from the outer peripheral surface of the intermediate transfer belt (501) is provided. 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 for the first color of the second sheet following the image formation process of the fourth color M of the first sheet. The process proceeds to the image forming process (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-described embodiment, the copying machine having only one photosensitive drum 1 has been described. However, the present invention may be configured such that, for example, a plurality of photosensitive drums as shown in FIG. The present invention can also be applied to the image forming apparatus.
FIG. 2 shows 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), each 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 photosensitive members (21BK), (21M), (21Y), and (21C), there are a charging device, a laser beam exposure unit from the writing unit (12), and each color of black, magenta, yellow, and cyan Developing devices (20BK), (20M), (20Y), (20C), primary transfer bias rollers (23BK), (23M), (23Y), (23C) as a primary transfer means, cleaning devices (not shown) ), And a photosensitive member static elimination device (not shown). 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), (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 conveyance 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 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.
In the present invention, in addition to the intermediate transfer belt type image forming apparatus using the intermediate transfer belt (501) or (22) as described above, instead of the intermediate transfer belt (501) or (22). The present invention can also be applied to a transfer conveyance belt type image forming apparatus using a transfer conveyance belt. Also, this transfer / conveyor belt type image forming apparatus can be applied to any of the above-mentioned 1-drum system and 4-drum system.

In the above process, a bias required for transfer is applied in the step of transferring from the photoconductor to the intermediate transfer belt or the step of transferring from the intermediate transfer belt to the paper. The value is set so that the color balance is satisfied.
This is also ideal for various fluctuation factors such as environmental fluctuations, belt resistance changes during long-term use, toner charge and adhesion, photoreceptor charge potential changes, paper type and physical property changes, etc. It is controlled by process control so that it becomes a clear image.
At this time, the primary and secondary transfer bias values are also controlled within a certain range.
In order to improve the transfer performance, the transfer bias is controlled to be higher, but at this time, if the belt resistance is highly voltage-dependent, there is no margin for the change in bias, regardless of the process control control range, A minute electric discharge occurs in the transfer nip, and the line image portion is scattered, or an abnormal image is generated in which the image of the portion is lost by reverse transfer in which the image once transferred to the transfer target is returned again.
Since the image forming apparatus of the present invention uses the intermediate transfer member of the present invention, it is possible to perform high-quality image formation that does not cause abnormal images over a long period of time.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited only to the following Example at all.
The particle size of carbon black in the following examples is measured as follows.
Device: Nano Track UPA150 (manufactured by Nikkiso Co., Ltd.)
Measurement parameters: particle refractive index 1.82, particle specific gravity 1.86 g / cm ³
Solvent refractive index 1.47, solvent viscosity 1.63 mPa · s
Measurement conditions: The sample solution was diluted 200 times with a solvent and measured at a measurement time of 240 sec.

Example 1
-Preparation of carbon black dispersion-
The resistance control agent dispersion composition of the following formulation is dispersed for 12 hours under the condition of a rotation speed of 200 rpm using a ball mill (using 2 mmφ zirconia balls) to obtain a carbon black dispersion (hereinafter referred to as dispersion (A)). Obtained.
Resistance control agent; carbon black (special black 4: manufactured by Degussa) ... 10 parts by weight dispersant; 2-butyne 1-ol: 4 parts by weight (carbon number of R _{1 in} general formula (1) = 0 (hydrogen atom), carbon number of R ₂ = 0 (hydrogen atom) ), R ₃ carbon number = 1, compound of dispersant (1))
Solvent: N-methyl-2-pyrrolidone (NMP) (Kanto Chemical Co., Ltd .: Special grade)・ 86 parts by weight

-Preparation of seamless belt coating solution-
First, each equimolar amount of biphenyl-3,4,3 ′, 4′-tetracarboxylic acid anhydride and p-phenylenediamine was polymerized in an N-methyl-2-pyrrolidone solvent to obtain a polyamic acid solution. Got.
To this, the carbon black dispersion was prepared so that the carbon black was 20% by mass of the solid content of the polyamic acid, stirred well, and mixed to prepare a seamless belt coating solution.

-Production of seamless belt A-
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 seamless belt coating solution is uniformly applied to the inner surface of the cylinder while rotating the cylinder at 50 rpm (times / minute). The solution was applied by casting.
When the predetermined amount was completely poured and the coating film spread evenly, the number of rotations was increased to 100 rpm, the hot air circulating dryer was put in, and the temperature was gradually raised to 120 ° C. and heated for 60 minutes.
Furthermore, it heated up and heated at 200 degreeC for 20 minute (s), and rotation was stopped.
The cylinder on which the coating film was formed by slowly cooling was taken out, put into a heating furnace (baking furnace) capable of high temperature treatment, heated to 350 ° C. stepwise, and heat-treated (baked) for 30 minutes.
Next, after stopping the heating, the cylinder on which the coating film was formed was taken out after being gradually cooled to room temperature, and the formed coating film was peeled off from the inner surface of the cylinder to produce a seamless belt A having a thickness of 80 μm.

(Comparative Example 1)
-Production of seamless belt B-
The same as Example 1 except that a carbon black dispersion liquid (hereinafter referred to as dispersion liquid (B)) to which no dispersant (1) was added in Example 1 was prepared and a seamless belt coating liquid was prepared using this. Thus, a seamless belt B was produced.

(Example 2)
-Production of seamless belt C-
Example 1 A carbon black dispersion was prepared by changing the amount of dispersant (1) added from 4 parts by weight to 0.009 parts by weight in Example 1, and a seamless belt coating liquid was prepared using this. In the same manner as in Example 1, a seamless belt C was produced.

(Example 3)
-Production of seamless belt D-
Example 1 A carbon black dispersion was prepared by changing the amount of dispersant (1) added from 4 parts by weight to 10.1 parts by weight in Example 1, and a seamless belt coating liquid was prepared using this. In the same manner as in Example 1, a seamless belt D was produced.

Example 4
-Fabrication of seamless belt E-
In Example 1, the dispersant (1) is represented by the following formula (2) (carbon number of R _{1 in} the general formula (1) = 20, carbon number of R ₂ = 20, carbon number of R ₃ = 20) In the same manner as in Example 1 except that a carbon black dispersion added with 4 parts by weight was prepared and a seamless belt coating solution was prepared using this, a seamless belt E was produced.

(Example 5)
-Fabrication of seamless belt F-
In Example 1, the dispersant (1) is represented by the following formula (3) (carbon number of R _{1 in} formula (1) = 21, carbon number of R ₂ = 20, carbon number of R ₃ = 20) In the same manner as in Example 1 except that a carbon black dispersion added with 4 parts by weight was prepared and a seamless belt coating solution was prepared using this, a seamless belt F was produced.

（実施例６）
−シームレスベルトＧの作製−
実施例１において、カーボンブラック分散液調製の際に、更にポリアミック酸をカーボンブラックに対して２０重量％（固形分）添加し、分散させた以外は、実施例１と同様にして、シームレスベルトＧを作製した。

(Example 6)
-Production of seamless belt G-
In Example 1, a seamless belt G was prepared in the same manner as in Example 1 except that, during the preparation of the carbon black dispersion, 20% by weight (solid content) of polyamic acid was further added to and dispersed in the carbon black. Was made.

(Example 7)
-Preparation of seamless belt coating solution-
First, an equimolar amount of pyromellitic anhydride and 4,4′-diphenylmethane diisocyanate was polymerized at 150 ° C. in an N-methylpyrrolidone solvent to obtain a polyamideimide solution having a solid content of 15% by weight. .
To this solution, the dispersion liquid (A) prepared in Example 1 was prepared so that the carbon black was 24% by weight of the solid content of polyamideimide, stirred well, and mixed to prepare a seamless belt coating liquid. did.

-Production of seamless belt H-
Next, in the same manner as in Example 1, a metal cylinder having an inner diameter of 100 mm and a length of 300 mm having a mirror-finished inner surface was used as a mold, and the cylinder was rotated at 50 rpm (times / minute) while the seamless belt coating was performed. The working liquid was applied to the inner surface of the cylinder so as to be cast uniformly.
When the predetermined amount was completely poured and the coating film spread evenly, the number of revolutions was increased to 100 rpm, and the hot air circulating dryer was introduced, gradually heated to 120 ° C. and heated for 30 minutes.
Thereafter, the rotation is stopped, the cylinder on which the coating film has been formed by slow cooling is taken out, put into a heating furnace (baking furnace) capable of high temperature treatment, heated to 250 ° C., and heated for 60 minutes (baking). did.
Next, after stopping the heating, after slowly cooling to room temperature, the cylinder on which the coating film was formed was taken out, and the formed coating film was peeled off from the inner surface of the cylinder to produce a seamless belt H having a thickness of 80 μm.

(Comparative Example 2)
-Fabrication of seamless belt I-
A seamless belt I was produced in the same manner as in Example 7 except that the dispersion liquid (B) produced in Comparative Example 1 was used.

(Example 8)
-Production of seamless belt J-
Example 7 A carbon black dispersion was prepared by changing the amount of the dispersant (1) added from 4 parts by weight to 0.009 parts by weight in Example 7, and a seamless belt coating liquid was prepared using this carbon black dispersion. In the same manner as in Example 7, a seamless belt J was produced.

Example 9
-Production of seamless belt K-
Example 7 A carbon black dispersion was prepared by changing the amount of the dispersant (1) added from 4 parts by weight to 10.1 parts by weight in Example 7, and a seamless belt coating liquid was prepared using the carbon black dispersion. In the same manner as in Example 7, a seamless belt K was produced.

(Example 10)
-Production of seamless belt L-
In Example 7, the dispersant (1) is represented by the following formula (2) (carbon number of R _{1 in} the general formula (1) = 20, carbon number of R ₂ = 20, carbon number of R ₃ = 20) In the same manner as in Example 7 except that a carbon black dispersion added with 4 parts by weight was prepared and a seamless belt coating solution was prepared using this, a seamless belt L was produced.

(Example 11)
-Production of seamless belt M-
In Example 7, the dispersant (1) is represented by the following formula: dispersant (3) (carbon number of R _{1 in} formula (1) = 21, carbon number of R ₂ = 20, carbon number of R ₃ = 20) In the same manner as in Example 7 except that a carbon black dispersion added with 4 parts by weight was prepared and a seamless belt coating solution was prepared using this, a seamless belt M was produced.

Example 12
-Production of seamless belt N-
In Example 7, a seamless belt N was prepared in the same manner as in Example 7 except that, during the preparation of the carbon black dispersion, 20% by weight (solid content) of polyamic acid was further added to and dispersed in the carbon black. Was made.
Next, the volume average particle diameter (μm) was measured using a particle size analyzer (manufactured by Nikkiso Co., Ltd.) for each carbon black dispersion and each seamless belt coating liquid obtained in Examples and Comparative Examples. The results are shown in Table 1, and the volume resistance value was measured using Hiresta (manufactured by Mitsubishi Chemical Corporation) for 10 arbitrary points on each seamless belt of Examples and Comparative Examples as follows.

The volume resistance value was measured by applying a 100 V bias and measuring the value for 10 seconds after application.
The difference in common logarithm between the maximum value and the minimum value of each measured value was evaluated as variation. As this value is larger, the variation is larger, and when it exceeds 1, it is not preferable in actual use.
The applied bias was measured at 10 V and 100 V, and the voltage dependence was also evaluated. The voltage dependence was evaluated by the difference between the common logarithm of the measured value when 10 V was applied and the measured value when 100 V was applied. As this value is larger, the voltage dependency is larger, and if it exceeds 2, it is not preferable for practical use.

Furthermore, each seamless belt of the example and the comparative example was mounted as an intermediate transfer belt of the image forming apparatus shown in FIG. 2, and the halftone image density to be formed was adjusted to approximately 0.8.
About the obtained halftone image, the degree of occurrence of a blurred image which is a spot-like density unevenness was evaluated.
With respect to the obtained halftone image, the degree of occurrence of a blurred image that is spotted density unevenness was evaluated.
◎: Very good ○: Good △: No problem in actual use ×: Very bad

  From the results shown in Table 1, by using the dispersant represented by the general formula (1), not only can the particle diameter of the resistance control agent dispersion be reduced, but also the resistance control agent dispersion and the heat resistant binder resin can be used. Even in a state where the (precursor) solution is mixed and dispersed to form a coating solution, it is possible to keep the particle size small with almost no aggregation.

Therefore, when a seamless belt is formed using the coating liquid of the present invention and used as an intermediate transfer belt of an electrophotographic apparatus, the electrical resistance is very uniform and does not vary, and durability such as heat resistance and mechanical characteristics Excellent quality and high quality images are formed.
On the other hand, in the case of the comparative example in which no dispersant was used, the variation in electric resistance and the voltage dependence were large, and the image was very bad.

FIG. 2 is a schematic view of a main part for explaining a seamless belt used for a belt member of an image forming apparatus according to the present invention and an image forming apparatus using the same. 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.

Explanation of symbols

[About Figure 1]
P transfer paper L exposure means 70 discharging roller 80 ground roller 200 photosensitive drum 201 photosensitive member cleaning device 202 discharging lamp 203 charging charger 204 discharging lamp 205 discharging lamp 210 belt conveying device 230 revolver developing unit 231Y Y developing unit 231K Bk developing unit 231C C developing machine 231M M developing machine 270 fixing device 271 fixing roller 272 fixing roller 500 intermediate transfer unit 501 intermediate transfer belt 503 toner seal member 504 belt cleaning blade 505 lubricant coating 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 The toner image 514 optical sensor 600 the secondary transfer unit 601 transfer paper guiding plate 605 secondary transfer bias roller 606 transfer paper discharger 608 cleaning blade 610 a registration roller 801 primary transfer power source 802 secondary transfer power supply About 2]
P transfer paper 10 printer main body 12 image writing unit 13 image forming unit 14 paper feeding unit 15 fixing device 16 registration roller 20BK developing device 20M developing device 20Y developing device 20C developing device 21BK photoconductor 21M photoconductor 21Y photoconductor 21C photoconductor 22 Intermediate transfer belt 23BK Primary transfer bias roller 23M Primary transfer bias roller 23Y Primary transfer bias roller 23C Primary transfer bias roller 25 Belt cleaning device 50 Transfer conveyance belt 60 Secondary transfer bias roller 70 Static elimination bias roller

Claims (14)

  An intermediate transfer member to which a toner image obtained by developing a latent image formed on an image bearing member with toner is transferred. The intermediate transfer member is a resin material or a precursor thereof and an organic solvent. An intermediate transfer member comprising at least a film-forming layer formed from an intermediate transfer member coating solution containing a base resin in which acetylene alcohol and carbon black are dispersed.   The intermediate transfer member according to claim 1, wherein the resin material or a precursor thereof is one of a polyimide resin and a polyamideimide resin, or a precursor thereof. The intermediate transfer according to claim 1, wherein the acetylene alcohol is represented by the following general formula (1), and R ₁ , R ₂ , and R ₃ each have 20 or less carbon atoms. body.

(R ₁ , R ₂ and R ₃ in the formula represent a hydrogen atom or 1 to 20 carbon chains which may be branched, and the carbon chain may contain an unsaturated bond.)   The intermediate transfer member according to any one of claims 1 to 3, wherein the content of acetylene alcohol is 1 to 100% by weight based on carbon black.   The intermediate transfer member according to any one of claims 1 to 4, wherein the base resin is one of a polyimide resin and a polyamide-imide resin.   6. The intermediate transfer member according to claim 1, wherein the intermediate transfer member is a seamless belt.   A method for producing an intermediate transfer body, comprising forming an intermediate transfer body using a coating liquid for an intermediate transfer body containing a carbon black dispersion containing a resin material or a precursor thereof, acetylene alcohol and carbon black.   The intermediate transfer member according to claim 7, wherein the resin material or a precursor thereof is a solution of an organic solvent solution, and the carbon black dispersion is dispersed in the organic solvent solution. Production method. 9. The carbon number of the alkyl group (R ₁ , R ₂ , R ₃ ) of the acetylene alcohol represented by the following general formula (1) in the acetylene alcohol is 20 or less, respectively. A method for producing an intermediate transfer member.

(R ₁ , R ₂ and R ₃ in the formula represent a hydrogen atom or 1 to 20 carbon chains which may be branched, and the carbon chain may contain an unsaturated bond.)   The intermediate transfer member coating solution is obtained by dispersing a carbon black dispersion obtained by further dispersing a base resin or a precursor thereof in addition to acetylene alcohol and carbon black in the resin material or a precursor solution thereof. The method for producing an intermediate transfer member according to claim 7 or 8, wherein the base resin is any one of a polyimide resin and a polyamideimide resin, or a precursor thereof.   The method for producing an intermediate transfer member according to claim 9, wherein the carbon black dispersion contains the same resin as the resin material or a precursor thereof.   The method for producing an intermediate transfer member according to any one of claims 7 to 10, wherein the volume average particle diameter of carbon black in the carbon black dispersion is 10 to 300 nm.   A latent image is formed and an image carrier capable of carrying a toner image; a developing unit that develops the latent image formed on the image carrier with toner; and a toner image developed by the developing unit is primarily transferred. The intermediate transfer member according to any one of claims 1 to 6, wherein the intermediate transfer member includes: an intermediate transfer member; and a transfer unit that secondarily transfers the toner image carried on the intermediate transfer member to a recording medium. An image forming apparatus which is an intermediate transfer member.   The image forming apparatus according to claim 13, wherein the image forming apparatus is a full-color image forming apparatus, and a plurality of latent image carriers having developing units for respective colors are arranged in series.

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