JP4379243B2 - Image forming method, image forming apparatus, electrophotographic photosensitive member, and image forming unit - Google Patents

Description

  The present invention relates to an image forming method, an image forming apparatus, an electrophotographic photoreceptor used therefor, and an image forming unit.

  In recent years, color copying machines and color printers are increasingly demanding color images. Color image forming methods with high practical value can be broadly classified into commonly used names: transfer drum method, intermediate transfer method, KNC method (a method for creating a multi-color superimposed image on a photoconductor and transferring them all at once), tandem There are four types of methods.

  Of course, since these are names given from different viewpoints, there are naturally, for example, an intermediate transfer system and a tandem system.

  As one form of an image forming method for forming a tandem color image, a toner image is formed on the surface of each electrophotographic photoreceptor (hereinafter also simply referred to as a photoreceptor) corresponding to each color of yellow, magenta, cyan, and black. An image forming method for forming a color image by superimposing toner images on a transfer material is known (for example, see Patent Document 1).

  This tandem color image forming method forms a color image by superimposing toner images of different hues formed by a plurality of image forming units on a transfer material, so that an electrophotographic system capable of forming a color image at high speed is used. Suitable for developing an image forming apparatus.

  In this tandem color image formation, the toner image is transferred directly from the photosensitive member of each image forming unit to a transfer material (hereinafter also referred to as recording paper) and the toner images are superimposed, so that an image accompanying a transfer failure of the toner image. Defects are likely to occur.

  For example, in the transfer of toner from a photoconductor to a transfer material, transfer defects are likely to occur depending on the type of transfer material, resulting in image defects such as image density reduction, transfer omission, and character dust due to transfer repelling. As a result, it tends to be a color image with reduced sharpness.

  In order to improve the transferability that causes image defects, the surface layer of the photoconductor contains fine particles, the surface is made uneven, and the toner adhesion on the photoconductor surface is reduced, improving the transferability. Technology has been studied. For example, it has been reported that alkylsilsesquioxane resin fine particles are contained in the photosensitive layer (see, for example, Patent Document 2).

  However, the alkylsilsesquioxane resin fine particles have a hygroscopic property, and in a high-humidity environment, there arises a problem that the wettability of the surface of the photoreceptor, that is, the surface energy increases, and the transferability tends to decrease. On the other hand, in order to reduce the surface energy of the photoreceptor, an electrophotographic photoreceptor containing a fluororesin powder has been reported. However, the fluororesin powder has a problem that sufficient surface strength cannot be obtained, streak failure due to scratches on the surface of the photoreceptor is liable to occur, and image blur is likely to occur (see, for example, Patent Document 3). .

  In other words, in the color image forming method in which the toner image is directly transferred from the electrophotographic photosensitive member to the transfer material by the tandem method, in order to prevent image defects such as a drop in image density that is conspicuous in the color image, image omission and character dust. However, it is not sufficient to improve the photoconductor as described above, and it is necessary to further improve the transferability of the toner image from the photoconductor to the transfer material, and to transfer the toner image on the transfer material so as not to cause image defects. It is.

  Recently, electrophotographic image technology is also attracting attention in the field of light printing due to the fact that there is no hassle of creating plates, and print-on that provides only the number of books needed for small orders. It has also been developed in a demand type image forming method.

  In such a printing field, the types of paper used for image formation (for example, thick paper and coated paper) will increase significantly compared to those used in conventional copying machines and printers. And good transferability is required.

  In order to obtain a good image even on thick paper or coated paper, a corresponding image forming method has been proposed in which the bias applied to the auxiliary means is changed according to the paper type (see, for example, Patent Document 4).

However, even if the applied bias is changed, in the image forming method using a known photoreceptor, the transferability is poor, and the toner image on the surface of the photoreceptor is stably applied to all types of paper (for example, thick paper, coated paper, etc.). It was difficult to transfer and it was difficult to obtain a good color image. In order to develop into the field of light printing, the advent of an image forming method capable of obtaining a good image for all types of paper is awaited.
JP 2001-222129 A Japanese Patent Laid-Open No. 5-181291 JP-A 63-56658 JP 2003-280456 A

  In the present invention, by using a photoconductor having excellent transfer performance, each color forming toner image is formed on the photoconductor using toner whose color is changed for each image forming unit, and each color toner image is transferred from the photoconductor. Even if the images are sequentially superimposed and transferred on the material, a toner image with high image density and no character dust can be obtained, and paper such as coated paper and cardboard, which is difficult to transfer with conventional techniques and is difficult to obtain a good toner image. An object of the present invention is to provide an image forming method capable of obtaining a good image even with seeds.

  The present invention is achieved by adopting the following configuration.

1. A plurality of image forming units having at least an electrophotographic photosensitive member, a charging step, an exposing step, a developing step, and a transferring step are arranged and provided on the electrophotographic photosensitive member using a toner whose color is changed for each image forming unit. An image in which each color toner image is formed, and each color toner image is sequentially superimposed and transferred onto the transfer material from the electrophotographic photosensitive member to form a color toner image, and the color toner image is fixed to form a color image. In the forming method, the electrophotographic photosensitive member contains a charge transporting material, the charge transporting material has a chemical structure represented by the following general formula (1), and has a distribution based on n. X + y is 80.2 % or less, where x is the composition ratio of x and y is the composition ratio of the 2-position component compound.

前記一般式Ａ中、Ａｒ_１は１価のメチル基又はメトキシ基で置換された芳香族基、又は無置換の芳香族基を示し、Ａｒ_２は２価の置換、無置換の芳香族基、２価のフラン基又はチオフェン基又は下記一般式（２）を示し、Ｒ_１〜Ｒ_３は水素原子、置換、無置換のアルキル基、１価の置換、無置換の芳香族基を示し、Ａはトリアリールアミン基を含有する２価の基又は下記一般式（３）の基を示す。但し、Ａｒ_１とＲ_１は互いに結合して環を形成してもよい。又、複数のＡｒ_１、Ｒ_１、Ｒ_２、Ｒ_３は互いに異なっていてもよい。ｐ、ｑは各々０又は１の整数を表す。

一般式（２）中、Ｙは単結合、酸素原子、硫黄原子、−ＣＨ＝ＣＨ−、又は−Ｃ（Ｒ_４）（Ｒ_５）−であり、Ｒ_４、Ｒ_５は水素原子又は炭素数１〜４のアルキル基であり、Ｒ_４とＲ_５が互いに結合してアルキレン環を形成してもよい。

一般式（３）中、Ｘ_１は単結合、アルキレン基、酸素原子又は硫黄原子を表し、Ｒ_６は置換、無置換のアルキル基、置換、無置換の芳香族基を示す。 General formula (1)
X- (CTM group) n-Y
In the general formula (1), the CTM group is a charge transporting group, and X and Y represent the chemical structure of the following general formula A. N represents an integer of 0 to 10.

In the general formula A, Ar ₁ represents an aromatic group substituted with a monovalent methyl group or a methoxy group, or an unsubstituted aromatic group, Ar ₂ represents a divalent substituted, unsubstituted aromatic group, A divalent furan group or a thiophene group or the following general formula (2) is shown, R _{1 to} R ₃ represent a hydrogen atom, a substituted or unsubstituted alkyl group, a monovalent substituted or an unsubstituted aromatic group, and A Represents a divalent group containing a triarylamine group or a group of the following general formula (3). However, Ar ₁ and R ₁ may be bonded to each other to form a ring. A plurality of Ar ₁ , R ₁ , R ₂ and R ₃ may be different from each other. p and q each represents an integer of 0 or 1.

In General Formula (2), Y is a single bond, an oxygen atom, a sulfur atom, —CH═CH—, or —C (R ₄ ) (R ₅ ) —, and R ₄ and R ₅ are a hydrogen atom or a carbon number. 1 to 4 alkyl groups, and R ₄ and R ₅ may be bonded to each other to form an alkylene ring.

In the general formula (3), X ₁ represents a single bond, an alkylene group, an oxygen atom or a sulfur atom, and R ₆ represents a substituted, unsubstituted alkyl group, a substituted or unsubstituted aromatic group.

2. The plurality of image forming units are four image forming units, including an image forming unit having a black color toner, an image forming unit having a yellow color toner, an image forming unit having a magenta color toner, and a cyan color toner. 2. The image forming method according to 1 above, comprising an image forming unit.

3. 3. The image forming method as described in 1 or 2 above, wherein x + y in the general formula (1) is in the following range.

30% ≦ x + y ≦ 80.2 %
4). The electrophotographic photoreceptor is a laminated electrophotographic photoreceptor in which a charge generation layer having a charge generation material, a charge transport layer having a charge transport material, and a protective layer as necessary are laminated in this order on a conductive substrate. 4. The image forming method according to any one of items 1 to 3, which is characterized in that

5). The electrophotographic photoconductor outermost surface layer of the image forming method according to any one of the 1 to 4, characterized that you have had an antioxidant.

6). Rotation linear velocity of the electrophotographic photosensitive member, an image forming method according to any one of the 1 to 5, wherein Der Rukoto than 200 mm / sec.

前記一般式Ａ中、Ａｒ_１は１価のメチル基又はメトキシ基で置換された芳香族基、又は無置換の芳香族基を示し、Ａｒ_２は２価の置換、無置換の芳香族基、２価のフラン基又はチオフェン基又は下記一般式（２）を示し、Ｒ_１〜Ｒ_３は水素原子、置換、無置換のアルキル基、１価の置換、無置換の芳香族基を示し、Ａはトリアリールアミン基を含有する２価の基又は下記一般式（３）の基を示す。但し、Ａｒ_１とＲ_１は互いに結合して環を形成してもよい。又、複数のＡｒ_１、Ｒ_１、Ｒ_２、Ｒ_３は互いに異なっていてもよい。ｐ、ｑは各々０又は１の整数を表す。

一般式（２）中、Ｙは単結合、酸素原子、硫黄原子、−ＣＨ＝ＣＨ−、又は−Ｃ（Ｒ_４）（Ｒ_５）−であり、Ｒ_４、Ｒ_５は水素原子又は炭素数１〜４のアルキル基であり、Ｒ_４とＲ_５が互いに結合してアルキレン環を形成してもよい。

一般式（３）中、Ｘ_１は単結合、アルキレン基、酸素原子又は硫黄原子を表し、Ｒ_６は置換、無置換のアルキル基、置換、無置換の芳香族基を示す。 7). A plurality of image forming units having at least an electrophotographic photosensitive member, a charging unit, an exposing unit, a developing unit, and a transferring unit are arranged, and a toner whose color is changed for each image forming unit is used on the electrophotographic photosensitive member. An image in which each color toner image is formed, and each color toner image is sequentially superimposed and transferred onto the transfer material from the electrophotographic photosensitive member to form a color toner image, and the color toner image is fixed to form a color image. In the forming apparatus, the electrophotographic photosensitive member contains a charge transporting material, the charge transporting material has a chemical structure of the following general formula (1), and has a distribution based on n, and is the largest component compound X + y is 80.2% or less, where x is the composition ratio of x and y is the composition ratio of the 2-position component compound.
General formula (1)
X- (CTM group) n-Y
In the general formula (1), the CTM group is a charge transporting group, and X and Y represent the chemical structure of the following general formula A. N represents an integer of 0 to 10.

In the general formula A, Ar ₁ represents an aromatic group substituted with a monovalent methyl group or a methoxy group, or an unsubstituted aromatic group, Ar ₂ represents a divalent substituted, unsubstituted aromatic group, A divalent furan group or a thiophene group or the following general formula (2) is shown, R _{1 to} R ₃ represent a hydrogen atom, a substituted or unsubstituted alkyl group, a monovalent substituted or an unsubstituted aromatic group, and A Represents a divalent group containing a triarylamine group or a group of the following general formula (3). However, Ar ₁ and R ₁ may be bonded to each other to form a ring. A plurality of Ar ₁ , R ₁ , R ₂ and R ₃ may be different from each other. p and q each represents an integer of 0 or 1.

In General Formula (2), Y is a single bond, an oxygen atom, a sulfur atom, —CH═CH—, or —C (R ₄ ) (R ₅ ) —, and R ₄ and R ₅ are a hydrogen atom or a carbon number. 1 to 4 alkyl groups, and R ₄ and R ₅ may be bonded to each other to form an alkylene ring.

In the general formula (3), X ₁ represents a single bond, an alkylene group, an oxygen atom or a sulfur atom, and R ₆ represents a substituted, unsubstituted alkyl group, a substituted or unsubstituted aromatic group.

8). An electrophotographic photosensitive member, characterized in that you use in an image forming apparatus according to 7.

9. The image forming unit, characterized in that for use in an image forming apparatus according to 7.

  According to the image forming method of the present invention, a toner image having a high density and no character dust can be obtained, and a good toner image can be obtained even with paper quality such as coated paper or cardboard, which is difficult to transfer with a conventional technique and difficult to obtain a good toner image. Has an excellent effect.

  When the present inventors have used a photoconductor produced using a charge transport material (CTM) having a high charge mobility and a high speed response in a conventional electrophotographic image forming apparatus, a toner image formed on the surface of the photoconductor Considering that the transfer performance of transferring to a transfer material is poor, the study was conducted.

  This phenomenon is particularly caused by high temperature and high humidity (for example, 30 ° C., 80% RH), low temperature and low humidity (for example, 10 ° C., 20% RH), and a high-speed machine (for example, the rotational linear velocity (peripheral velocity) of the photoconductor is 200 mm / mm). It has been confirmed that the transfer material (for example, cardboard, coated paper) with poor transferability becomes prominent.

  In the photoreceptor using the mixed compound having the compound structure of the general formula (1) (hereinafter also referred to as oligomer CTM) as a charge transport material, the present inventors have used high temperature and high humidity (for example, 30 ° C., 80% RH). ), Low temperature and low humidity (for example, 10 ° C., 20% RH), high speed machine (for example, the rotational linear velocity of the photosensitive member is 200 mm / sec or more), and transfer materials with poor transferability (for example, thick paper, coated paper) are also good. It has been found that transfer performance can be obtained.

  By using this photoconductor, each color toner image is formed on the photoconductor using toner whose color is changed for each image forming unit, and the respective color toner images are sequentially superimposed and transferred from the photoconductor onto the transfer material. However, it is possible to obtain a toner image with a high image density and no character dust, and a good toner image can be obtained even with paper types such as coated paper and cardboard, which are difficult to transfer with a conventional technique and difficult to obtain. An image forming method can be provided.

  Since the oligomer CTM used in the present invention has a molecular weight distribution even if the weight average molecular weight is large, the oligomer CTM was dissolved well in a solvent for dissolving the binder resin, and this oligomer CTM was prepared by dissolving in the binder resin solution. In the charge transport layer coating solution, it has been confirmed that the oligomer CTM and the binder resin are uniformly mixed and phase separation does not occur.

  The charge transport layer formed by applying this charge transport layer coating solution is more uniform than the charge transport layer formed using a single molecular weight charge transport material after the coating is formed. Is presumed to be formed.

  In addition, the photoconductor produced using the above oligomer CTM maintains a stable photoconductor surface without the oligomer CTM floating or aggregating on the photoconductor surface even if stored for a long time. It has been confirmed that it can be done.

  The reason why the transfer performance is good is not clear, but a photoreceptor having a charge transport layer formed in a state where oligomer CTM and binder resin are uniformly mixed has a uniform electrical property on the photoreceptor layer and its surface. Therefore, a high image density can be maintained, image fog does not occur, and the toner image is uniformly and satisfactorily transferred to a transfer material that is difficult to transfer, so that residual toner is not generated. Estimated.

  In particular, it has been confirmed that the performance has been significantly improved by reducing the image density due to continuous printing, dust particles around the character area when printing characters, and transfer materials with poor transfer properties (eg, thick paper, coated paper). Has been.

  In addition, even with a photoreceptor provided with a protective layer on the surface of the charge transport layer in order to improve the durability and charging process of the photoreceptor, a uniform charge transport layer surface in which the oligomer CTM and the binder resin are uniformly mixed is formed. Therefore, it is presumed that the bonding property between the protective layer and the charge transport layer is improved, and the number of charge trap sites is reduced. As a result, it has been confirmed that even if a protective layer is provided on the charge transport layer, the image characteristics and transfer characteristics are excellent.

  First, the photoconductor will be described.

[Photoreceptor]
The photoreceptor according to the present invention has a charge generation layer having at least a charge generation material, a charge transport layer having a charge transport material, and a protective layer as necessary, on a conductive support.

<Charge transport material>
The charge transport material used in the present invention has the chemical structure of the following general formula (1), and the composition ratio of the compound of the maximum component of the mixed compound having a distribution based on n is x, the composition ratio when the y, x + y is Ru Tei is equal to or less than 80.2%.

General formula (1)
X- (CTM group) n-Y
In the general formula (1), the CTM group is a charge transporting group, and X and Y represent the chemical structure of the following general formula A. N represents an integer of 0 to 10.

In the present invention, x + y of 80.2 % or less means that compounds having different numbers of chain structures of charge transporting groups (CTM groups) are mixed.

Among the mixed compounds, when the composition ratio (existence ratio) of the compound of the maximum component is x, and the composition ratio (existence ratio) of the compound of the 2-position component is y, x + y is 80.2 % or less, It means that the mixed compound contains at least three compounds of the above general formula (1) having different n.

In the present invention, the value of x + y is 80.2 % or less, and preferably 30% ≦ x + y ≦ 80.2% . The weight average molecular weight of the oligomer CTM is preferably 650 to 2,500, and more preferably 800 to 2,300. The weight average molecular weight is a value represented by weight average molecular weight in terms of polystyrene.

  The CTM group of the general formula (1), that is, the charge transporting group is a group whose chemical structural group has a property of having drift mobility of electrons or holes. Another definition is Time-Of- It can be defined as a group capable of obtaining a detection current resulting from charge transport by a known method capable of detecting charge transport performance such as the Flight method.

  When the CTM group cannot exist by itself, the compound of the general formula (H (CTM group) H) in which hydrogen atoms are added to both ends of the CTM group may be a charge transporting compound.

X + y where x is the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the general formula (1) and has a distribution based on n, and y is the composition ratio of the compound of the 2-position component. Although various chemical structures can be considered as specific examples of the mixed compound having a content of 80.2 % or less, in the present invention, these mixed compounds can be produced by a series of synthesis methods and can achieve the object of the present invention. Examples of the (charge transport material) include mixed compounds of the following general formula A, general formula B, and general formula C.

  The mixed compound of general formula A has the following chemical structure.

In the general formula A, Ar ₁ represents an aromatic group substituted with a monovalent methyl group or a methoxy group, or an unsubstituted aromatic group, Ar ₂ represents a divalent substituted, unsubstituted aromatic group, A divalent furan group or a thiophene group or the following general formula (2) is shown, R _{1 to} R ₃ represent a hydrogen atom, a substituted or unsubstituted alkyl group, a monovalent substituted or an unsubstituted aromatic group, and A Represents a divalent group containing a triarylamine group or a group of the following general formula (3). However, Ar ₁ and R ₁ may be bonded to each other to form a ring. A plurality of Ar ₁ , R ₁ , R ₂ and R ₃ may be different from each other. p and q each represents an integer of 0 or 1.

In General Formula (2), Y is a single bond, an oxygen atom, a sulfur atom, —CH═CH—, or —C (R ₄ ) (R ₅ ) —, and R ₄ and R ₅ are a hydrogen atom or a carbon number. 1 to 4 alkyl groups, and R ₄ and R ₅ may be bonded to each other to form an alkylene ring .

In the general formula (3), X ₁ represents a single bond, an alkylene group, an oxygen atom or a sulfur atom, and R ₆ represents a substituted, unsubstituted alkyl group, a substituted or unsubstituted aromatic group.

  The mixed compound of the general formula B has the following chemical structure.

In the general formula B, Ar ₁ represents a divalent substituted, unsubstituted aromatic group, divalent furan group or thiophene group, or the general formula (2), wherein R _{1 to} R ₃ are hydrogen atoms, substituted , An unsubstituted alkyl group, a monovalent substituted, an unsubstituted aromatic group, A represents a divalent group containing a triarylamine group or a group of the general formula (3), and B represents a monovalent group. A substituted or unsubstituted aromatic group. However, a plurality of B, R ₁ , R ₂ and R ₃ may be different from each other. m represents an integer of 0 or 1, respectively.

  In General Formula A and General Formula B, the divalent group containing a triarylamine group has a structure in which a trivalent linking group of a nitrogen atom is bonded to an aromatic ring, and the entire group A group having a divalent linking group is meant.

As the monovalent substituted or unsubstituted aromatic group of Ar _{1 in} the general formulas A and B, a substituted or unsubstituted phenyl group, a naphthyl group, and the like are preferable, and the substituent has 1 to 4 carbon atoms. Of these, an alkyl group, an alkoxy group, a phenyl group, a halogen atom and the like are preferable.
As the divalent substituted or unsubstituted aromatic group of Ar ₂ , a phenylene group, a naphthylene group, a biphenylene group or the like is preferable, and as the substituent, an alkyl group is preferable. A divalent furan group and a divalent thiophene group are also preferred.

R _{1 to} R ₃ represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a monovalent substituted or an unsubstituted aromatic group, a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, An alkoxy group, an unsubstituted phenyl group, a halogen, or a phenyl group having an alkyl group having 1 to 4 carbon atoms is preferred.

  As the divalent group of A, in addition to the group of the general formula (3), the group of the general formula (4) or the general formula (6) is preferable as the divalent group containing a triarylamine group.

R ₆ in the general formula (3) represents a substituted, unsubstituted alkyl group, substituted, or unsubstituted aromatic group, preferably an alkyl group having 1 to 4 carbon atoms, a phenyl group, or the like.

Ar ₃ in the general formula (4) is a substituted or unsubstituted monovalent aromatic group, preferably a phenyl group substituted with an unsubstituted phenyl group, an alkyl group having 1 to 4 carbon atoms or an alkoxy group. Is mentioned.

Ar ₄ and Ar ₅ in the general formula (6) represent a substituted or unsubstituted monovalent aromatic group, preferably substituted with an unsubstituted phenyl group, an alkyl group having 1 to 4 carbon atoms or an alkoxy group. And phenyl group.

  Hereinafter, typical chemical structures of the general formula A and the general formula B are listed below, but the present invention uses a mixture (mixed compound) of compounds having different n in the following chemical structures as a charge transport material. That is. Moreover, even if the following chemical structure is the same, if p or q of General Formula A or m of General Formula B is different, it is another mixed compound. For example, the following chemical structure No. 1A is another mixed compound in which p or q is 0 and 1. Further, even if p or q is the same, another mixed compound is obtained if the distribution is different.

  Specific examples of general formula A

The above compound examples are examples of chemical structures in which a plurality of Ar ₁ , R ₁ , R ₂ and R ₃ in the general formula A are the same, but in the present invention, the plurality of Ar ₁ , R ₁ and R _{2 are the same.} , R ₃ are not the same. For example, the following chemical structure example of the general formula A ′ is also exemplified as the chemical structure example of the general formula (1).

In general formula A ′, Ar ₁ and Ar ₁ ′ represent a monovalent substituted or unsubstituted aromatic group, Ar ₂ represents a divalent substituted, unsubstituted aromatic group, furan group or thiophene group, Wherein R _{1 to} R ₃ , R ₁ ′ to R ₃ ′ represent a hydrogen atom, a substituted or unsubstituted alkyl group, a monovalent substituted or unsubstituted aromatic group, and A represents triaryl A divalent group containing an amine group or a group of the general formula (3) is shown. However, Ar ₁ and R ₁ , Ar ₁ ′ and R ₁ ′ may be bonded to each other to form a ring. p and q each represents an integer of 0 or 1.

The chemical structures of typical compounds of the general formula A ′ are listed below. In the present invention, each chemical structure has a distribution based on n and the composition ratio of the compound of the maximum component is x, and the composition ratio of the compound of the 2-position component is y, and x + y is 80.2 % or less. A mixed compound is used as a charge transport material.

  Below, the synthesis example of the said mixed compound (general formula A) is described.

  In the following synthesis examples, raw materials and the like will be described using the numbers given in the compound synthesis mechanism (scheme).

  Synthesis Example (1); Synthesis of Compound (Exemplary Chemical Structure 21A (p = q = 0))

  A 100 ml four-headed flask was equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer, and 4 (potassium-tert-butoxide): 1.68 g (0.015 mol) and 20 ml of tetrahydrofuran (hereinafter THF) were added. Was stirred while being introduced.

  1 compound: 2.06 g (0.006 mol), 2 compound: 1.13 g (0.003 mol) and 3 compound: 1.92 g (0.0063 mol) were dissolved in 20 ml of THF to dissolve 4 (potassium-tert- The solution was slowly added dropwise to a mixed solution of butoxide / THF while maintaining the internal temperature at 45 ° C. or lower. After completion of dropping, the reaction was carried out for 5 hours while maintaining the internal temperature of 45 to 50 ° C.

  A separate 200 ml beaker was equipped with a stirrer, and 20 ml of methanol was added and stirred. After pouring the reaction solution reacted for 5 hours, 20 ml of water was further poured, and the mixture was stirred for about 30 minutes and filtered. Methanol / water = 1/1 Washed with about 40 ml and dried at 50-60 ° C. overnight to obtain crude crystals.

  This crude crystal was dissolved in 30 ml of toluene, 3 g of Wakogel B-0 (Wako Pure Chemical Industries) was added, and the mixture was stirred for about 30 minutes and filtered. Wakogel B-0 was washed with 30 ml of toluene, and the filtrate and washings were concentrated to dryness. 10 ml of ethyl acetate was added and dissolved, dropped into 60 ml of methanol and purified by reprecipitation, filtered and dried to obtain 2.54 g of the compound having the exemplified chemical structure 21A (p = q = 0). As a result of high performance liquid chromatography and mass spectrometry, the obtained compound is a mixture of n of 0 to 4, and the composition ratio (area ratio of high performance liquid chromatography) is n = 0/1/2/3/4 = It was 25.4 / 48.8 / 18.1 / 6.3 / 1.4.

  The measurement conditions for high performance liquid chromatography were as follows.

Measuring instrument: Shimadzu LC6A (manufactured by Shimadzu Corporation)
Column: CLC-ODS (manufactured by Shimadzu Corporation)
Detection wavelength: 290 nm
Mobile phase: mixed solvent of methanol / tetrahydrofuran = 3/1 Mobile phase flow rate: about 1 ml / min
The composition ratio of the mixed compound is defined by the area ratio of each component after composition separation by the liquid chromatography (area ratio in% display, total composition ratio 100%). Among the measurement conditions, the measuring device, column, mobile phase, and the like may be changed to others as long as the separation of the mixed compound can be clearly performed and the same result as in the present invention can be obtained.

  Synthesis Example (2); Synthesis of Compound (Exemplary Chemical Structure 21A (p = 1, q = 0))

A 100 ml four-headed flask is equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer, and 4 (potassium-tert-butoxide): 1.68 g (0.015 mol) and 20 ml of THF are added and stirred while introducing nitrogen. did.
1 compound: 2.06 g (0.006 mol), 2 compound: 1.13 g (0.003 mol) and 3 compound: 2.08 g (0.0063 mol) were dissolved in 20 ml of THF to dissolve 4 (potassium-tert- The solution was slowly added dropwise to a mixed solution of butoxide / THF while maintaining the internal temperature at 45 ° C. or lower. After completion of dropping, the reaction was carried out for 5 hours while maintaining the internal temperature of 45 to 50 ° C.

  Separately, a 200 ml beaker was equipped with a stirrer, and 20 ml of methanol was added and stirred. After pouring the reaction solution reacted for 5 hours, 20 ml of water was further poured, and the mixture was stirred for about 30 minutes and filtered. Methanol / water = 1/1 Washed with about 40 ml and dried at 50-60 ° C. overnight to obtain crude crystals.

  This crude crystal was dissolved in 30 ml of toluene, 3 g of Wakogel B-0 (Wako Pure Chemical Industries) was added, and the mixture was stirred for about 30 minutes and filtered. Wakogel B-0 was washed with 30 ml of toluene, and the filtrate and washings were concentrated to dryness. This was dissolved in 10 ml of ethyl acetate, added dropwise to 60 ml of methanol, purified by reprecipitation, filtered and dried to obtain 2.75 g of the compound having the exemplified chemical structure 21A (p = 1, q = 0). As a result of the same high performance liquid chromatography and mass spectrometry as described above, the obtained compound is a mixture of n = 0-4, and the composition ratio (area ratio of high performance liquid chromatography) is n = 0/1/2 / 3/4 = 33.4 / 46.8 / 15.0 / 4.0 / 0.8.

  Synthesis Example (3); Synthesis of Compound (Exemplary Chemical Structure 14A (p = 1, q = 0))

A 100 ml four-headed flask is equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer, and 4 (potassium-tert-butoxide): 1.68 g (0.015 mol) and 20 ml of THF are added and stirred while introducing nitrogen. did.
1 compound: 1.89 g (0.006 mol), 2 compound: 1.13 g (0.003 mol) and 3 compound: 1.60 g (0.0063 mol) were dissolved in 20 ml of THF to obtain 4 (potassium-tert- The solution was slowly added dropwise to a mixed solution of butoxide / THF while maintaining the internal temperature at 45 ° C. or lower. After completion of dropping, the reaction was carried out for 5 hours while maintaining the internal temperature of 45 to 50 ° C.

  Separately, a 200 ml beaker was equipped with a stirrer, and 20 ml of methanol was added and stirred. After pouring the reaction solution reacted for 5 hours, 20 ml of water was further poured, and the mixture was stirred for about 30 minutes and filtered. Methanol / water = 1/1 Washed with about 40 ml and dried at 50-60 ° C. overnight to obtain crude crystals.

  This crude crystal was dissolved in 30 ml of toluene, 3 g of Wakogel B-0 (Wako Pure Chemical Industries) was added, and the mixture was stirred for about 30 minutes and filtered. Wakogel B-0 was washed with 30 ml of toluene, and the filtrate and washings were concentrated to dryness. 10 ml of ethyl acetate was added and dissolved, dropped into 60 ml of methanol and purified by reprecipitation, filtered and dried to obtain 2.32 g of a compound having the exemplified chemical structure 14A (p = 1, q = 0). As a result of the same high performance liquid chromatography and mass spectrometry as described above, the obtained compound is a mixture of n = 0-4, and the composition ratio (area ratio of high performance liquid chromatography) is n = 0/1/2 / 3/4 = 30.1 / 45.4 / 16.7 / 6.0 / 1.8.

  Specific examples of general formula B

More compounds embodiment, a plurality of B in the general formula B, R _1, R _2, but R ₃ are the same of compound examples, in the present invention, the plurality of B, R _1, R _2, R ₃ Are also included. For example, the following compound of the general formula B ′ is also exemplified as the compound of the general formula B.

In general formula B ′, Ar ₁ represents a divalent substituted or unsubstituted aromatic group, furan group or thiophene group, and R _{1 to} R ₃ and R ₁ ′ to R ₃ ′ represent a hydrogen atom, substituted and unsubstituted. An alkyl group, a monovalent substituted or unsubstituted aromatic group, A represents a divalent group containing a triarylamine group or a group of the general formula (3), and B and B ′ represent a monovalent group. A substituted or unsubstituted aromatic group. m represents an integer of 0 or 1, respectively.

The chemical structures of representative compounds of the general formula B ′ are listed below. In the present invention, each chemical structure has a distribution based on n and the composition ratio of the compound of the maximum component is x, and the composition ratio of the compound of the 2-position component is y, and x + y is 80.2 % or less. A mixed compound is used as a charge transport material.

  Below, the synthesis example of the said mixed compound (general formula B) is described.

  Synthesis Example (4); Synthesis of Compound (Exemplary Chemical Structure 12B (m = 0))

  A 100 ml four-headed flask was equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer, and 4 (potassium-tert-butoxide): 1.96 g (0.075 mol) and 20 ml of tetrahydrofuran (hereinafter THF) were added. Was stirred while being introduced.

  1 compound: 1.0 g (0.003 mol), 2 compound: 2.65 g (0.007 mol) and 3 compound: 2.52 g (0.008 mol) were dissolved in 20 ml of THF, and the above 4 (potassium-tert. -Butoxy) / THF was slowly added dropwise while maintaining the internal temperature at 45 ° C. or lower. After completion of dropping, the reaction was carried out for 5 hours while maintaining the internal temperature of 45 to 50 ° C.

  Separately, a 200 ml beaker was equipped with a stirrer, and 20 ml of methanol was added and stirred. After pouring the reaction solution reacted for 5 hours, 20 ml of water was further poured, and the mixture was stirred for about 30 minutes and filtered. Methanol / water = 1/1 Washed with about 40 ml and dried at 50-60 ° C. overnight to obtain crude crystals.

  The crude crystals were dissolved in 30 ml of toluene, 3 g of Wakogel B-0 (Wako Pure Chemical Industries) was added, and the mixture was stirred for about 30 minutes and filtered. Wakogel B-0 was washed with 30 ml of toluene, and the filtrate and washings were concentrated to dryness. 10 ml of ethyl acetate was added and dissolved therein, and the resulting solution was added dropwise to 60 ml of methanol for reprecipitation purification, followed by filtration and drying to obtain 3.20 g of a compound having an exemplary chemical structure 12B (m = 0).

  As a result of the same high performance liquid chromatography and mass spectrometry as in Synthesis Example 1A, the obtained compound was a mixture of n = 0 to 5, and the composition ratio (area ratio of high performance liquid chromatography) was n = 0/1/2. /3/4=24.3/44.4/21.5/7.2/2.3/0.3.

  The measurement conditions for high performance liquid chromatography were as follows.

  Synthesis Example (5); Synthesis of Compound (Exemplary Chemical Structure 11B (m = 0))

  A 100 ml four-headed flask is equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer, and 4 (potassium-tert-butoxide): 1.96 g (0.075 mol) and 20 ml of THF are added and stirred while introducing nitrogen. did.

  1 compound: 1.0 g (0.003 mol), 2 compound: 2.46 g (0.007 mol) and 3 compound: 2.41 g (0.008 mol) were dissolved in 20 ml of THF to dissolve 4 (potassium-tert- The solution was slowly added dropwise to a mixed solution of butoxide / THF while maintaining the internal temperature at 45 ° C. or lower. After completion of dropping, the reaction was carried out for 5 hours while maintaining the internal temperature of 45 to 50 ° C.

  Separately, a 200 ml beaker was equipped with a stirrer, and 20 ml of methanol was added and stirred. After pouring a reaction liquid into this, 20 ml of water was further poured, and it stirred for about 30 minutes and filtered. Methanol / water = 1/1 Washed with about 40 ml and dried overnight at 50-60 ° C. to obtain crude crystals.

  This crude crystal was dissolved in 30 ml of toluene, 3 g of Wakogel B-0 (Wako Pure Chemical Industries) was added, and the mixture was stirred for about 30 minutes and filtered. Wakogel B-0 was washed with 30 ml of toluene, and the filtrate and washings were concentrated to dryness. This was dissolved in 10 ml of ethyl acetate, dropped into 60 ml of methanol, purified by reprecipitation, filtered and dried to obtain 3.35 g of a compound having the exemplified chemical structure 11B (m = 0).

  As a result of the same high performance liquid chromatography and mass spectrometry as described above, the obtained compound was a mixture of n = 0 to 4, and the composition ratio (area ratio of high performance liquid chromatography) was n = 0/1/2/3. /4=32.5/45.0/16.5/6.2/1.6.

  The mixed compound of general formula C has the following chemical structure.

In general formula C, Ar ₁ is a monovalent substituted or unsubstituted aromatic group, Ar ₂ is a divalent substituted, unsubstituted aromatic group, divalent heterocyclic group, or general formula (8) above. R represents a substituted, unsubstituted alkyl group, monovalent substituted, or unsubstituted aromatic group. However, the plurality of Ar ₁ , Ar ₂ , and R may be different from each other.

In the general formula (8), Y represents an oxygen atom, a sulfur atom, —CH═CH—, or —CH ₂ —CH ₂ —. However R _1, R ₂ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

In general formula C, Ar ₁ is a monovalent substituted or unsubstituted aromatic group, preferably a phenyl group substituted with an unsubstituted phenyl group, an alkyl group having 1 to 4 carbon atoms or an alkoxy group. It is done.

Further, the divalent substituted or unsubstituted aromatic group of Ar ₂ is preferably a phenylene group, a naphthylene group, a biphenylene group or the like, and the substituent is preferably an alkyl group. As the divalent heterocyclic group for Ar _2, a divalent furan group, a divalent thiophene group, and the like are preferable.

  Specific examples of general formula C

  Below, the synthesis example of the said mixed compound (general formula C) is described.

Synthesis Example (6): Synthesis of Compound (Exemplary Chemical Structure 17C) A 100 ml four-headed flask was equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer, and 2,4-dimethylaniline: 4.08 g (0. 04 mol), iodobenzene: 4.08 g (0.02 mol), m-diiodobenzene: 9.9 g (0.03 mol), copper powder 1.27 g (0.02 mol), potassium carbonate 11.04 g (0.08 mol) ) And allowed to react at 190 ° C. for 30 hours while introducing nitrogen.
The reaction solution was cooled to about 60 ° C., 200 ml of THF was added, and the mixture was stirred and filtered. The filtrate was concentrated and dissolved in 100 ml of toluene, 10 g of Wakogel B-0 (Wako Pure Chemical Industries) was added, and the mixture was stirred for about 30 minutes and filtered. Wakogel B-0 was washed with 30 ml of toluene, and the filtrate and washings were concentrated to dryness. This was dissolved by adding 20 ml of THF, dropped into 120 ml of methanol, purified by reprecipitation, filtered and dried to obtain 5.15 g of a compound having an exemplary chemical structure 17C.

  As a result of high performance liquid chromatography and mass spectrometry, the obtained compound was n = 0/1/2/3/4/5/6/7 = 2.7 / 9.0 / 24.3 / 34.2 / 20. 1 / 7.8 / 1.7 / 0.2. Moreover, the weight average molecular weight (polystyrene conversion) Mw calculated | required from the gel permeation chromatography (GPC) was 910.

Synthesis Example (7); Synthesis of Compound (Exemplary Chemical Structure 48C) A 100 ml four-headed flask was equipped with a nitrogen introduction tube, a condenser tube, a thermometer, and a stirrer, and 3,4-dimethylaniline: 6.05 g (0.0. 05 mol), iodobiphenyl: 5.60 g (0.02 mol), bis (4-bromophenyl) ether: 13.11 g (0.04 mol), copper powder 1.59 g (0.025 mol), potassium carbonate 13.8 g ( 0.1 mol) was added and reacted at 190 ° C. for 30 hours while introducing nitrogen. The reaction solution was cooled to about 60 ° C., 200 ml of THF was added, and the mixture was stirred and filtered. The filtrate was concentrated and dissolved in 100 ml of toluene, 10 g of Wakogel B-0 (Wako Pure Chemical Industries) was added, and the mixture was stirred for about 30 minutes and filtered. Wakogel B-0 was washed with 30 ml of toluene, and the filtrate and washings were concentrated to dryness. This was dissolved in 20 ml of THF, added dropwise to 120 ml of methanol, purified by reprecipitation, filtered and dried to obtain 10.56 g of the compound having the exemplified chemical structure 48C.

  As a result of high performance liquid chromatography and mass spectrometry, the obtained compound was n = 0/1/2/3/4/5/6/7/8 = 0.9 / 3.4 / 12.0 / 22.8. /31.3/19.9/6.9/2.5/0.3. Moreover, the weight average molecular weight (polystyrene conversion) Mw calculated | required from the gel permeation chromatography (GPC) was 1684.

<Structure of photoconductor>
Next, the conductive support, the intermediate layer, the charge generation layer, the charge transport layer, the conductive layer provided as necessary, and the protective layer constituting the photoreceptor according to the present invention will be described.

(Conductive support)
The conductive support used in the photoreceptor may be either a sheet or a cylinder, but the cylindrical conductive support is more preferable for designing the image forming apparatus compactly.

  Cylindrical conductive support means a cylindrical support necessary for forming an endless image by rotating. Conductivity is within a range of 0.1 mm or less in straightness and 0.1 mm or less in deflection. A support is preferred. By setting the straightness and shake range within the above ranges, good image formation can be achieved.

As a material for the conductive support, a metal drum such as aluminum or nickel, a plastic drum deposited with aluminum, tin oxide, indium oxide, or the like, or a paper / plastic drum coated with a conductive substance can be used. The conductive support preferably has a specific resistance of 10 ³ Ωcm or less at room temperature.

  Moreover, you may use the electroconductive support body in which the alumite film | membrane by which the sealing process was carried out was formed in the surface. The alumite treatment is usually performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid, etc., but anodizing treatment in sulfuric acid gives the most preferable result. In the case of anodizing treatment in sulfuric acid, the sulfuric acid concentration is preferably 100 to 200 g / L, the aluminum ion concentration is 1 to 10 g / L, the liquid temperature is about 20 ° C., and the applied voltage is preferably about 20 V. It is not limited. The average film thickness of the anodized film is usually 20 μm or less, particularly preferably 10 μm or less.

(Middle layer)
In the present invention, in order to improve the adhesion between the conductive support and the photosensitive layer, or to prevent charge injection from the support, an intermediate layer (including an undercoat layer) is provided between the conductive support and the photosensitive layer. ) Can also be provided. Examples of the material for the intermediate layer include polyamide resins, vinyl chloride resins, vinyl acetate resins, and copolymer resins containing two or more of these resin repeating units. Of these resins, a polyamide resin is preferable as a resin capable of reducing an increase in residual potential due to repeated use. The film thickness of the intermediate layer using these resins is preferably 0.01 to 0.8 μm.

  Examples of the intermediate layer preferably used in the present invention include an intermediate layer using a curable metal resin obtained by thermosetting an organic metal compound such as a silane coupling agent or a titanium coupling agent. The thickness of the intermediate layer using a curable metal resin is preferably 0.1 to 2 μm.

  An intermediate layer preferably used in the present invention includes an intermediate layer in which inorganic particles are dispersed in a binder resin. The average particle diameter of the inorganic particles is preferably 0.01 to 1 μm. In particular, an intermediate layer in which N-type semiconductive fine particles subjected to surface treatment are dispersed in a binder is preferable. For example, an intermediate layer in which titanium oxide having an average particle size of 0.01 to 1 μm, which has been surface-treated with silica / alumina treatment and a silane compound, is dispersed in a polyamide resin. The film thickness of such an intermediate layer is preferably 1 to 20 μm.

(Charge generation layer)
The charge generation layer contains a charge generation material (CGM). Other substances may contain a binder resin and additives as necessary.

  A known charge generation material (CGM) can be used as the charge generation material (CGM). For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azulenium pigment, or the like can be used. Among these, CGM which can minimize the increase in residual potential due to repeated use has a crystal structure capable of taking a stable aggregate structure among a plurality of molecules, specifically, a phthalocyanine pigment having a specific crystal structure, CGM of a perylene pigment is mentioned. For example, CGMs such as titanyl phthalocyanine having a maximum peak at a Bragg angle 2θ of 27.2 ° with respect to Cu—Kα rays and benzimidazole perylene having a maximum peak at 2θ of 12.4 have little deterioration due to repeated use. Potential increase can be reduced.

  When a binder resin is used as a dispersion medium for dispersing the charge generation material in the charge generation layer, a known resin can be used as the binder resin, and preferred resins include formal resin, butyral resin, silicone resin, and silicone-modified butyral. Examples thereof include resins and phenoxy resins. The ratio of the binder resin to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The thickness of the charge generation layer is preferably 0.01 μm to 2 μm.

(Charge transport layer)
The charge transport layer contains a charge transport material (CTM) and a binder resin. Other substances may contain additives such as antioxidants as necessary.

  As the charge transport material (CTM), the oligomer CTM is used. In addition to the oligomer CTM, for example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used in combination. These charge transport materials are usually dissolved in a binder resin to form a layer. The thickness of the charge transport layer is preferably 10 to 40 μm.

  Examples of the binder resin used in the charge transport layer (CTL) include polystyrene-acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, Mention may be made of polycarbonate resins, silicone resins, melamine resins and copolymer resins containing two or more of the repeating unit structures of these resins. In addition to these insulating resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used.

  A polycarbonate resin is particularly preferable as the binder resin. The polycarbonate resin is particularly preferable in improving the dispersibility and electrophotographic characteristics of CTM. The ratio of the binder resin to the charge transport material is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  The charge transport layer preferably contains an antioxidant. Typical examples of the antioxidants prevent or suppress the action of oxygen on auto-oxidizing substances existing in the photoreceptor or on the photoreceptor surface under light, heat, discharge, or the like. It is a substance with properties. As the antioxidant, a known one can be used, and examples thereof include 2,6-di-tert-butyl-4-methylphenol.

(Conductive layer)
In the photoreceptor according to the present invention, a conductive layer may be provided on a conductive support. The conductive layer is a layer basically composed of a binder resin and a conductive pigment. The thickness of the conductive layer is preferably 0.3 to 10 μm, and more preferably 1 to 5 μm.

(Protective layer)
In the photoreceptor according to the present invention, a durability improving layer or a charge injection layer functioning as a charge injection may be provided as a protective layer on the charge transport layer for the purpose of improving the film durability.

  The durability improving layer is basically composed of a binder resin, and may be a layer formed by adding a charge transport material as necessary. The film thickness of the durability improving layer is preferably 0.3 to 10 μm, and more preferably 1 to 5 μm.

  The charge injection layer is a layer basically composed of conductive fine particles and a binder resin. As the binder resin for the charge injection layer, the same binder resin as that for the charge transport layer described above can be used.

As the conductive fine particles of the charge injection layer, fatty acid salts, higher alcohols, sulfate esters, fatty acid amines, quaternary ammonium salts, alkyl pyridium salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, Anionic, cationic, or nonionic organic electrolytes such as sorbitan alkyl esters and imidazoline derivatives; metals such as Au, Ag, Cu, Ni, Al; ZnO, TiO ₂ , SnO ₂ , In ₂ O ₃ , Sb ₂ O Metal oxides such as _3- containing SnO ₂ and In ₂ O ₃ -containing SnO ₂ ; metal fluorides such as MgF ₂ , CaF ₂ , BiF ₂ , AlF ₂ , SnF ₂ , SnF ₄ , TiF ₄ ; tetrainpropyl titanate, tetra Normal butyl titanate, titanium acetylacetonate, titanium lactate ethyl ester And mixtures thereof, and the like; organic titanium compounds. The thickness of the charge injection layer is preferably 0.3 to 10 μm, and more preferably 1 to 5 μm.

The volume resistance of the charge injection layer is preferably set in the range of 10 ¹⁰ to 10 ¹⁵ Ω · cm, and more preferably 10 ¹⁰ to 10 ¹⁴ Ω · cm. Since the film strength becomes weaker as the amount of conductive particles increases, it is preferable to reduce the amount of conductive particles within a range where the resistance and residual potential of the charge injection layer are acceptable.

  The preferred layer structure of the photoconductor used in the present invention is exemplified above, but the other layer structure of the photoconductor may be used.

  As a solvent or dispersion medium used for forming a layer such as an intermediate layer, a charge generation layer, a charge transport layer, a conductive layer, or a protective layer, n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1, 1-trichloroethane, trichloroethylene, tetrachloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethylsulfoxide De, and methyl cellosolve. Although this invention is not limited to these, Dichloromethane, 1, 2- dichloroethane, methyl ethyl ketone, etc. are used preferably. These solvents may be used alone or as a mixed solvent of two or more.

  Further, the coating solution for each layer is preferably filtered with a metal filter, a membrane filter or the like in order to remove foreign matters and aggregates in the coating solution before entering the coating step. For example, it is preferable to select a pleat type (HDC), a depth type (profile), a semi-depth type (profile star), etc., manufactured by Nippon Pole Co., Ltd. according to the characteristics of the coating solution and perform filtration.

  Coating methods such as dip coating, spray coating, circular amount regulation type coating, etc. are used as the coating processing method for manufacturing the photoreceptor, but the upper layer side coating processing does not dissolve the lower layer film as much as possible. Therefore, in order to achieve uniform coating processing, it is preferable to use a coating processing method such as spray coating or circular amount regulation type (a circular slide hopper type is a typical example). The charge injection layer is particularly preferably the above-described circular amount regulation type coating method. The circular amount regulation type coating is described in detail in, for example, Japanese Patent Application Laid-Open No. 58-189061.

  Next, an image forming apparatus using the image forming method will be described.

[Image forming apparatus]
A charging device, an image exposure device, a developing device, a transfer device, used in the image forming apparatus according to the present invention,
The fixing device and the image forming unit will be described in detail.

(Charging device)
The charging device is not particularly limited, and various charging devices such as a non-contact charging type (for example, corona charging) and a contact charging type (for example, roller, brush, blade, particle charging) can be used.

  Here, the particle charging is a method in which a conductive particle and a carrier that supports the conductive particle are included, and the photosensitive particle is charged by bringing the conductive particle into contact with the photosensitive member.

(Exposure equipment)
As the exposure apparatus, a laser beam scanner including a laser diode, a polygon mirror and the like is preferably used. This laser beam scanner outputs laser light whose intensity is modulated in accordance with the time-series electric digital pixel signal of the target image information, and scans and exposes the uniformly charged surface of the rotating photosensitive drum with the laser light.

(Developer)
As the developing device, each developing device using a two-component developer, a one-component magnetic developer, and a one-component non-magnetic developer can be used. The developing device develops the electrostatic latent image on the photoreceptor with toner to form a toner image.

(Transfer device)
As the transfer device, the same non-contact charging type (for example, corona charging) and contact charging type (for example, roller, brush, blade, particle charging) as the charging device can be used. The toner image on the surface of the photoreceptor is transferred onto a transfer material by a transfer device.

(Fixing device)
As the fixing device, contact fixing (heat roller, heat belt) and non-contact fixing (flash) devices can be used. The toner image transferred onto the transfer material by the fixing device is fixed to the transfer material.

(Image forming unit)
As the image forming unit, a unit in which a charger, an image exposure device, a developing device, a transfer or separator, and a cleaning device are integrally supported together with a photosensitive member is formed, and is a unit that can be attached to and detached from the device main body. It is good also as a structure which can be attached or detached using the guide means.

  FIG. 1 is a cross-sectional configuration diagram illustrating an example of an image forming apparatus (adopting corona charging) according to the present invention.

  In the image forming apparatus of FIG. 1, four sets of image forming units 20Y, 20M, 20C, and 20Bk are provided along the transfer material conveyance belt 115.

  Each image forming unit includes a photosensitive drum 21Y (21M, 21C, 21Bk), a scorotron charging device (charging means) 22Y (22M, 22C, 22Bk), an image exposure device 23Y (23M, 23C, 23Bk), and a developing unit 24Y ( 24M, 24C, 24Bk) and a cleaning device 25Y (25M, 25C, 25Bk), each toner image formed on the photosensitive drum (21Y, 21M, 21C, 21Bk) of each image forming unit is timed. The toner images are transferred onto the transfer material P conveyed together by a transfer device 34Y (34M, 34C, 34Bk) as transfer means to form a superimposed toner image.

  The transfer material P is transported on the transfer material transport belt 115, and is a separation member provided in the transport unit 160 at a predetermined interval with a charge eliminating action by a paper separation AC neutralizer 161 as a transfer material separating means. It is separated from the conveyor belt by the claw 210.

  Next, the transfer material P passes through the transport unit 160, and is then transported to a fixing device (fixing unit) 40 including the heating roller 41 and the pressure roller 42, and the heating roller 41 and the pressure roller 42 cause the transfer material P to be transported. The transfer material P is sandwiched by the formed nip portion T, and the superimposed toner image on the transfer material P is fixed by applying heat and pressure, and then is discharged outside the apparatus.

  In the image exposure apparatus, a scanning optical system using a semiconductor laser and a solid state scanner such as an LED or a liquid crystal shutter can be used as an image exposure light source.

  The transfer material transport belt 115 for transporting the transfer material is made conductive by adding a conductive filler such as carbon black to a polymer film such as polyimide, polycarbonate, PVdF, or a synthetic rubber such as silicone rubber or fluorine rubber. Are used, and either a drum shape or a belt shape may be used, but a belt shape is preferable from the viewpoint of the degree of freedom in device design.

  FIG. 2 is a cross-sectional configuration diagram showing an example of an image forming apparatus (adopting magnetic brush charging) according to the present invention.

  The main body of the electrophotographic apparatus is provided with a first image forming unit Pa, a second image forming unit Pb, a third image forming unit Pc, and a fourth image forming unit Pd, each having a different color (for example, yellow, cyan, magenta, and so on). A black image) is formed on the transfer material through a latent image, image and transfer process.

  The configuration of each image forming unit provided in the electrophotographic apparatus will be described by taking the first image forming unit Pa as an example.

  The first image forming unit Pa includes an electrophotographic photosensitive member (photosensitive drum) 61a, and the photosensitive drum 61a rotates in the direction of arrow a. 62a is a primary charger as a charging means, and a magnetic brush charger supported on a sleeve in contact with the photosensitive drum 61a is used. 67a is exposure light from an exposure device for forming an electrostatic latent image on the photosensitive drum 61a whose surface is uniformly charged by the primary charger 62a. Reference numeral 63a denotes a developing device as developing means for developing the electrostatic latent image carried on the photosensitive drum 61a to form a toner image, and holds color toner. 65a is a toner hopper and 66a is a supply roller. Reference numeral 64a denotes a transfer blade as transfer means for transferring the color toner image formed on the surface of the photosensitive drum 61a onto the surface of the transfer material conveyed by the belt-like transfer material carrier 68. The transfer blade 64a Is in contact with the back surface of the transfer material carrier 68 and is applied with a transfer bias by the bias applying means 60a.

  The first image forming unit Pa uniformly charges the photosensitive drum 61a by the primary charger 62a, forms an electrostatic latent image on the photosensitive member by the exposure light 67a, and electrostatically develops by the developing unit 63a. The back surface of the belt-shaped transfer material carrier 68 that develops the latent image with toner and carries the developed toner image on the first transfer portion (contact position between the photosensitive member and the transfer material). The image is transferred onto the surface of the transfer material by applying a transfer bias from the transfer blade 64a in contact with the side.

  The electrophotographic apparatus has a configuration similar to that of the first image forming unit Pa as described above as shown in FIG. 2, and the second image forming unit Pb having a different toner color held in the developing device, Four image forming units of the third image forming unit Pc and the fourth image forming unit Pd are provided side by side. For example, yellow toner is used for the first image forming unit Pa, magenta toner is used for the second image forming unit Pb, cyan toner is used for the third image forming unit Pc, and black toner is used for the fourth image forming unit Pd. Transfer of each toner onto the transfer material is sequentially performed at the transfer section of each image forming unit. In this step, the color toners are superimposed on each other by moving the transfer material once on the same transfer material while aligning the registration, and when completed, the transfer material is separated from the transfer material carrier 68 by the separation charger 74. Then, it is sent to the fixing device 70 by a conveying means such as a conveying belt, and a final full-color image is obtained by only one fixing.

  In FIG. 2, the transfer material carrier 68 is an endless belt-like member, and this belt-like member is moved in the direction of arrow e by the drive roller 80. 79 is a transfer belt cleaning device, 81 is a belt driven roller, and 82 is a belt static eliminator. Reference numeral 83 denotes a registration roller for conveying the transfer material in the transfer material holder to the transfer material carrier 68, and 84 is a paper feed roller.

  As the transfer means, a roller-like transfer roller can be used instead of the transfer blade.

  Further, a non-contact transfer unit that performs transfer by applying a transfer bias from a corona charger arranged in a non-contact manner on the back side of a transfer material carrier that is generally used instead of the contact transfer unit described above. It is also possible to use.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. In this embodiment, “part” means “part by mass”.

《Synthesis of charge transport material》
The charge transport material (oligomer CTM) used in the present invention was synthesized by the method described above.

  Table 1 shows the chemical structure, composition ratio, x + y value, and average molecular weight of typical charge transport materials synthesized.

<< Production of photoconductor >>
<Example 1>
(Conductive support)
An aluminum drum washed with ultrasonic water was used as a conductive support.

(Middle layer)
An intermediate layer coating solution was prepared by dispersing polyamide resin “CM4000” (manufactured by Toray Industries, Inc.) and titanium oxide (mass ratio 2/1) in a mixed solvent of methanol and chloroform (mass ratio 2/1). This coating solution was applied on an aluminum drum by a dip coating method, and then dried at 120 ° C. for 30 minutes to form an intermediate layer having a thickness of 1.0 μm.

(Charge generation layer)
Polyvinyl butyral resin as the binder resin and α-type oxytitanium phthalocyanine (mass ratio 2/1) as the charge generating material are dissolved and dispersed in a mixed solvent of 1,1,2-trichloroethane and dichloromethane to prepare a coating solution for the charge generating layer. did. This coating solution was applied onto the intermediate layer by a dip coating method, and then dried at 100 ° C. for 30 minutes to form a charge generation layer having a thickness of 0.2 μm.

(Charge transport layer)
“Compound 1A” as the charge transport material, bisphenol Z-type polycarbonate “Iupilon Z300” (manufactured by Mitsubishi Gas Chemical Company) as the binder resin, 2,6-di-tert-butyl-4-methylphenol as the antioxidant, The charge transport material / antioxidant was dissolved in 1,2-dichloroethane at a mass ratio of 1.0 / 0.8 / 0.1 to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method, and then dried at 100 ° C. for 1 hour to form an electrotransport moving layer having a thickness of 24 μm. This is referred to as “photosensitive member 1”.

<Example 2>
(Conductive support)
An aluminum drum washed with ultrasonic water was used as a conductive support.

(Middle layer)
An intermediate layer coating solution was prepared by dissolving 60 g of polyamide resin “Amilan CM-8000” (manufactured by Toray Industries, Inc.) in a mixed solvent (mass ratio 1/1) of 1600 ml of methanol and 400 ml of 1-butanol. This coating solution was applied on an aluminum drum by a dip coating method, and then dried at 130 ° C. for 30 minutes to form an intermediate layer having a thickness of 0.3 μm.

(Charge generation layer)
Dissolve and mix 60 g of titanyl phthalocyanine as a charge generating substance and 700 g of a silicone resin solution “KR5240, 15% xylene-butanol solution” (manufactured by Shin-Etsu Chemical Co., Ltd.) as a binder resin in 2000 ml of methyl ethyl ketone, and then disperse for 10 hours using a sand mill. A coating solution for charge generation layer was prepared. This coating solution was applied onto the intermediate layer by a dip coating method, and then dried at 100 ° C. for 30 minutes to form a charge generation layer having a thickness of 0.2 μm.

(Charge transport layer)
200 g of “Compound 2A” as a charge transport material and 300 g of bisphenol Z-type polycarbonate “Iupilon Z300” (manufactured by Mitsubishi Gas Chemical Company) as a binder resin were dissolved in 2000 ml of 1,2-dichloroethane to prepare a coating solution for a charge transport layer. This coating solution was applied onto the charge generation layer by a dip coating method, and then dried at 100 ° C. for 30 minutes to form a charge transport layer having a thickness of 20 μm. This is designated as “photosensitive member 2”.

<Example 3>
A photoconductor was formed in the same manner as in Example 2 except that the charge transport material “Compound 2A” of Example 2 was changed to the charge transport material “Compound 9C”. This is referred to as “photoreceptor 3”.

<Example 4>
(Protective layer (durability improving layer))
200 g of “Compound 9C” as a charge transport material and 300 g of bisphenol Z-type polycarbonate “Iupilon Z800” (Mitsubishi Gas Chemical Co., Ltd.) as a binder resin were dissolved in 2000 ml of 1,2-dichloroethane to prepare a coating solution for durability improvement layer. . This coating solution was applied onto the charge transport layer of Example 2 by a dip coating method, and then dried at 100 ° C. for 30 minutes to form a protective layer having a thickness of 3 μm. This is referred to as “photosensitive member 4”.

<Example 5>
(Protective layer (durability improving layer))
The molecular sieve 4A was added to 10 parts by mass of a polysiloxane resin composed of 80 mol% of methylsiloxane units and 20 mol% of methyl-phenylsiloxane units, and allowed to stand for 15 hours for dehydration treatment. This resin was dissolved in 10 parts by mass of toluene, and 5 parts by mass of methyltrimethoxysilane and 0.2 parts by mass of dibutyltin acetate were added thereto to prepare a uniform solution. To this solution, 6 parts by mass of dihydroxymethyltriphenylamine (Exemplary Compound T-1) and 0.3 part by mass of hindered amine (Exemplary Compound 2-1) were added and mixed to prepare a coating solution for a durability improving layer. This coating solution was applied onto the charge transport layer of Example 2 and then heat-cured at 120 ° C. for 1 hour to form a protective layer having a thickness of 3 μm. This is designated as “photoreceptor 5”.

<Example 6>
(Conductive support)
An aluminum drum washed with ultrasonic water was used as a conductive support.

(Middle layer)
To 160 parts of methoxyethanol, 27 parts of an 85% butanol solution of zirconium tetra-n-butoxide and 48 parts of titanium tetra-n-butoxide (manufactured by Kishida Chemical Co., Ltd.) are dropped, and a mixed solution of methoxyethanol / water = 160 parts / 11 parts. Was further added. A solution obtained by adding 20 parts of acetylacetone to 200 parts of methanol was further added dropwise to the mixed solution, and then 85 parts of a 10% by mass methanol solution of hydroxypropyl cellulose (manufactured by Tokyo Chemical Industry Co., Ltd.) was obtained. Was prepared. This coating solution was dip-coated on an aluminum drum, and then heated and dried at 120 ° C. for 15 minutes to form an intermediate layer having a thickness of 0.3 μm.

(Charge generation layer)
4 parts of oxytitanium phthalocyanine having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction, butyral resin “BX-” 1 part (manufactured by Sekisui Chemical Co., Ltd.) and 80 parts of cyclohexanone were dissolved and dispersed for 4 hours in a sand mill using φ1 mm glass beads, and then 115 parts of methyl ethyl ketone was added to prepare a dispersion for a charge generation layer. This coating solution was applied onto the intermediate layer by a dip coating method, and then dried at 100 ° C. for 30 minutes to form a charge generation layer having a thickness of 0.2 μm.

(Charge transport layer)
Charge transport layer coating solution by dissolving 10 parts of charge transport material “Compound 1B” and 10 parts of polycarbonate resin “Iupilon Z-200” (Mitsubishi Gas Chemical Co., Ltd.) in a mixed solvent of 20 parts of dichloromethane and 60 parts of monochlorobenzene. Was prepared. This coating solution was applied onto the charge generation layer by a dip coating method, and then dried at 115 ° C. for 60 minutes to form a charge transport layer having a thickness of 20 μm.

(Protective layer (charge injection layer))
50 parts of antimony-doped tin oxide ultrafine particles surface-treated with a compound of the following structural formula (treatment amount: 7%)

150 parts of ethanol was dispersed for 66 hours using a sand mill, and further 20 parts of polytetrafluoroethylene fine particles (average particle size 0.18 μm) were added, followed by further dispersion for 2 hours. Thereafter, 30 parts of a resol type phenol resin “PL-4804” (manufactured by Gunei Chemical Industry Co., Ltd.) was dissolved as a resin component to prepare a coating solution for a charge injection layer. This coating solution was applied onto the charge transport layer by a dip coating method, and then dried with hot air at a temperature of 145 ° C. for 1 hour to form a protective layer having a thickness of 3 μm. This is referred to as “photosensitive member 6”.

<Example 7>
(Conductive support)
An aluminum drum washed with ultrasonic water was used as a conductive support.

(Conductive layer)
A conductive layer coating solution prepared from the following materials was applied on an aluminum drum by a dipping method, and then heated and dried at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 15 μm.

Conductive pigment: 10 parts of tin oxide / antimony oxide-coated titanium oxide Resistance pigment: 10 parts of titanium oxide Binder resin: 10 parts of phenol resin “Priofen J-325” (Dainippon Ink Chemical Co., Ltd.) Leveling agent: Silicone oil “SH28PA” (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.001 part Solvent: methanol / methoxypropanol = 1/1, 20 parts (intermediate layer)
10 parts of a copolymerized polyamide resin “Amilan CM-8000” (manufactured by Toray Industries, Inc.), 30 parts of a methoxymethylated 6 nylon resin “Toresin EF-30T” (manufactured by Teikoku Kagaku), 400 parts of methanol and 200 parts of n-butanol. An intermediate layer coating solution was prepared by dissolving in a mixed solvent. This coating solution was dip-coated on the conductive layer, and then dried with hot air at 90 ° C. for 10 minutes to form an intermediate layer having a thickness of 0.68 μm.

(Charge generation layer)
7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 ° and 28.3 ° of black angle (2θ ± 0.2 °) with respect to CuKα characteristic X-ray 3 parts of a hydroxygallium phthalocyanine pigment having a strong diffraction peak, a strong peak, and a maximum diffraction peak at 28.3 °, 2 parts of a butyral resin “ESREC BX-1” (manufactured by Sekisui Chemical Co., Ltd.) and cyclohexanone 100 After dissolving and dispersing 4 parts in a sand mill apparatus for 4 hours, 90 parts of ethyl acetate was added to prepare a charge generation layer coating solution. This coating solution was dip-coated on the intermediate layer, and then dried with hot air at 82 ° C. for 15 minutes to form a charge generation layer having a thickness of 0.17 μm.

(Charge transport layer)
For charge transport layer, 7 parts of charge transport material “Compound 1C” and 10 parts of bisphenol Z type polycarbonate “Iupilon Z-400” (Mitsubishi Gas Chemical Co., Ltd.) are dissolved in a mixed solvent of 30 parts of dichloromethane and 40 parts of monochlorobenzene. A coating solution was prepared. This coating solution was dip-coated on the charge generation layer and then dried at 110 ° C. for 60 minutes to form a charge transport layer having a thickness of 17 μm.

(Protective layer (charge injection layer))
72 parts of antimony-doped tin oxide fine particles “T-1” (manufactured by Mitsubishi Materials) having an average particle diameter of 0.02 μm and surface-treated with methyl hydrogen silicone oil “KF99” (manufactured by Shin-Etsu Silicone), and fluorine-modified silane coupling agent “ 48 parts of antimony-doped tin oxide fine particles “T-1” (Mitsubishi Materials) having an average particle size of 0.02 μm surface-treated with “LS1090” (manufactured by Shin-Etsu Silicone Co., Ltd.) and acrylic monomer “trade name TMP3A-3” (Osaka Organic) (Chemical Co., Ltd.) 43.2 parts and ethanol 210 parts were dispersed in a sand mill for 90 hours.

  40.8 parts of tetrafluoroethylene resin particles “Lublon L-2” (manufactured by Daikin Industries, Ltd.) are mixed in this liquid and dispersed in a sand mill device for 2 hours. Further, 2,4-diethylthioxanthone is used as a photopolymerization initiator. 6.48 parts and 2.16 parts of 4,4′-bis (diethylamino) benzophenone as an initiator were added and dissolved to prepare a coating solution for charge injection layer.

  This coating solution is dip-coated on the charge transport layer, then photocured using a metal halide lamp, and further dried with hot air at 120 ° C. for 1 hour and 40 minutes to form a protective layer (charge injection layer) having a thickness of 6 μm. did. This is designated as “photoreceptor 7”.

<Comparative example 1>
A photoconductor was prepared in the same manner as in Example 2 except that the charge transport material “Compound 2A” in Example 2 was changed to the charge transport material “Compound 15A”. This is designated as “photoreceptor 8”.

<Comparative example 2>
A photoconductor was prepared in the same manner as in Example 2 except that the charge transport material “Compound 2A” in Example 2 was changed to the charge transport material “Compound 16B”. This is designated as “photosensitive member 9”.

<Comparative Example 3>
A photoconductor was prepared in the same manner as in Example 6 except that the charge transport material “Compound 1B” in Example 6 was changed to the charge transport material “Compound 13C”. This is designated as “photosensitive member 9”.

  Table 2 shows the layer structure of the photoreceptor, the charge generation material and the charge transport material used.

<Evaluation>
Evaluation of the photoreceptor obtained above was performed for the following evaluation items using the following image forming apparatus.

<Image forming device>
The photoreceptors 1 to 5, 8, and 9 were mounted on the image forming apparatus shown in FIG. 1 (adopting corona charging), and evaluation was performed with the peripheral speed of the photoreceptor set to 250 mm / sec.

  The photoconductors 6, 7, and 10 were mounted on the image forming apparatus shown in FIG. 2 (adopting magnetic brush charging), and evaluation was performed by setting the rotation speed of the photoconductor to 210 mm / sec.

<Evaluation item>
(Image density)
Using A4 quality fine paper (64 g / m ² ), the original image has a white background, black (Bk) and yellow (Y), magenta (M), cyan (C) solid (solid) image portion, character image portion, An A4 plate image having a halftone image portion is printed at 10,000 sheets in a one-sheet intermittent mode at a ratio of 10: 1 between a monochrome image and a color image at room temperature and humidity (20 ° C., 50% RH). The image density when printing 10,000 sheets was evaluated.

  The image density is measured using a “RD-918 densitometer” (manufactured by Macbeth Co., Ltd.), and is defined as a relative reflection density where the reflection density of fine paper is “0”.

Evaluation Criteria A: Each density of the solid (solid) image part of Bk and Y, M, C is 1.2 or more. Good: Each density of the solid (solid) image part of Bk, Y, M, C is 0. No problem in practical use at 8 or more. X: There is a practical problem when the density of any of the solid (solid) image portions of Bk, Y, M, and C is less than 0.8.

(Letter Chile)
Using A4 quality fine paper (64 g / m ² ), Bk, Y, M, and C letter images were printed in a low-temperature, low-humidity (10 ° C, 20% RH) environment. The toner dust around the characters was observed and evaluated.

Evaluation criteria ◎: Even if loupe observation, toner dust around the character is not observed, good ○: Cannot be visually confirmed, but with the loupe, toner dust around the character is observed, but there is no practical problem ×: Toner dust around the character is visually observed However, the sharpness of the characters is inferior and there are practical problems.

(Transferability to extra thick paper)
A4 with an ultra-thick postcard (thickness 0.4 mm) manufactured by Heart Co., Ltd., with a white background, Bk, Y, M, and C solid (solid) image portion, character image portion, and halftone image portion on the original image The plate image was continuously printed on 500 sheets of a monochrome image and a color image at a ratio of 10: 1 in an environment of high temperature and high humidity (30 ° C., 80% RH). The obtained print was evaluated according to the following evaluation criteria.

Evaluation criteria A: There were no ghost image defects due to residual transfer toner on 500 print images. O: A ghost image defect due to less than 5 transfer residual toners was observed on 500 print images, but practically. No problem level ×: A ghost image defect due to residual transfer toner is clearly recognized on five or more printed images on 500 sheets, which is a practical problem.

(Transferability to coated paper)
Using 500 sheets of coated paper (75 g / m ² ) manufactured by Daio Paper Co., Ltd., the original image has a white background, Bk, Y, M, and C solid (solid) image portions, character image portions, and halftone image portions. A black and white image and a color image were continuously printed on an A4 plate image at a ratio of 10: 1 in an environment of high temperature and high humidity (30 ° C., 80% RH). The ranks of the obtained prints were evaluated as follows.

Evaluation Criteria A: There were no image defects due to transfer omission on 500 print images. O: Image defects due to transfer omission of less than 5 sheets were observed on 500 print images, but there was no practical problem. : On 500 print images, image defects due to transfer defects are clearly observed on 5 or more sheets, which is a practical problem.

  The evaluation results are shown in Table 3.

  As is apparent from Table 3, the “photosensitive members 1 to 7” according to the present invention are compared with the comparative examples “photosensitive members 8 to 10” in comparison with the comparative examples “photosensitive members 8 to 10”. It can be seen that it is excellent in transferability to.

1 is a schematic diagram illustrating an example of an image forming apparatus (adopting corona charging) according to the present invention. 1 is a schematic view showing an example of an image forming apparatus (adopting magnetic brush charging) according to the present invention.

Explanation of symbols

20Y, 20M, 20C, 20Bk Image forming unit 21Y, 21M, 21C, 21Bk Photosensitive drum 22Y, 22M, 22C, 22Bk Charger 23Y, 23M, 23C, 23Bk Image exposure device 24Y, 24M, 24C, 24Bk Developer 25Y, 25M, 25C, 25Bk Cleaning device 34Y, 34M, 34C, 34Bk Transfer device 115 Transfer material conveyance belt P Transfer material

Claims (9)

A plurality of image forming units having at least an electrophotographic photosensitive member, a charging step, an exposing step, a developing step, and a transferring step are arranged and provided on the electrophotographic photosensitive member using a toner whose color is changed for each image forming unit. An image in which each color toner image is formed, each color toner image is sequentially superimposed and transferred from the electrophotographic photosensitive member to a transfer material to form a color toner image, and the color toner image is fixed to form a color image. In the forming method, the electrophotographic photosensitive member contains a charge transport material, the charge transport material has a chemical structure represented by the following general formula (1), and has the distribution based on n: X + y is 80.2% or less, where x is the composition ratio of x and y is the composition ratio of the 2-position component compound.
General formula (1)
X- (CTM group) n-Y
In the general formula (1), the CTM group is a charge transporting group, and X and Y represent the chemical structure of the following general formula A. N represents an integer of 0 to 10.

In the general formula A, Ar ₁ represents an aromatic group substituted with a monovalent methyl group or a methoxy group, or an unsubstituted aromatic group, Ar ₂ represents a divalent substituted, unsubstituted aromatic group, A divalent furan group or a thiophene group or the following general formula (2) is shown, R _{1 to} R ₃ represent a hydrogen atom, a substituted or unsubstituted alkyl group, a monovalent substituted or an unsubstituted aromatic group, and A Represents a divalent group containing a triarylamine group or a group of the following general formula (3). However, Ar ₁ and R ₁ may be bonded to each other to form a ring. A plurality of Ar ₁ , R ₁ , R ₂ and R ₃ may be different from each other. p and q each represents an integer of 0 or 1.

In General Formula (2), Y is a single bond, an oxygen atom, a sulfur atom, —CH═CH—, or —C (R ₄ ) (R ₅ ) —, and R ₄ and R ₅ are a hydrogen atom or a carbon number. 1 to 4 alkyl groups, and R ₄ and R ₅ may be bonded to each other to form an alkylene ring.

In the general formula (3), X ₁ represents a single bond, an alkylene group, an oxygen atom or a sulfur atom, and R ₆ represents a substituted, unsubstituted alkyl group, a substituted or unsubstituted aromatic group. The plurality of image forming units are four image forming units, including an image forming unit having a black color toner, an image forming unit having a yellow color toner, an image forming unit having a magenta color toner, and a cyan color toner. The image forming method according to claim 1, comprising an image forming unit. The image forming method according to claim 1, wherein x + y in the general formula (1) is in the following range.
30% ≦ x + y ≦ 80.2% The electrophotographic photoreceptor is a laminated electrophotographic photoreceptor in which a charge generation layer having a charge generation material, a charge transport layer having a charge transport material, and a protective layer as necessary are laminated in this order on a conductive substrate. The image forming method according to claim 1, wherein the image forming method is an image forming method. The image forming method according to claim 1, wherein the outermost surface layer of the electrophotographic photosensitive member has an antioxidant. 6. The image forming method according to claim 1, wherein a rotational linear velocity of the electrophotographic photosensitive member is 200 mm / sec or more. A plurality of image forming units having at least an electrophotographic photosensitive member, a charging unit, an exposing unit, a developing unit, and a transferring unit are arranged, and a toner whose color is changed for each image forming unit is used on the electrophotographic photosensitive member. An image in which each color toner image is formed, and each color toner image is sequentially superimposed and transferred onto the transfer material from the electrophotographic photosensitive member to form a color toner image, and the color toner image is fixed to form a color image. In the forming apparatus, the electrophotographic photosensitive member contains a charge transporting material, the charge transporting material has a chemical structure of the following general formula (1), and has a distribution based on n, and is the largest component compound X + y is 80.2% or less, where x is the composition ratio of x and y is the composition ratio of the 2-position component compound.
General formula (1)
X- (CTM group) n-Y
In the general formula (1), the CTM group is a charge transporting group, and X and Y represent the chemical structure of the following general formula A. N represents an integer of 0 to 10.

In the general formula A, Ar ₁ represents an aromatic group substituted with a monovalent methyl group or a methoxy group, or an unsubstituted aromatic group, Ar ₂ represents a divalent substituted, unsubstituted aromatic group, A divalent furan group or a thiophene group or the following general formula (2) is shown, R _{1 to} R ₃ represent a hydrogen atom, a substituted or unsubstituted alkyl group, a monovalent substituted or an unsubstituted aromatic group, and A Represents a divalent group containing a triarylamine group or a group of the following general formula (3). However, Ar ₁ and R ₁ may be bonded to each other to form a ring. A plurality of Ar ₁ , R ₁ , R ₂ and R ₃ may be different from each other. p and q each represents an integer of 0 or 1.

In General Formula (2), Y is a single bond, an oxygen atom, a sulfur atom, —CH═CH—, or —C (R ₄ ) (R ₅ ) —, and R ₄ and R ₅ are a hydrogen atom or a carbon number. 1 to 4 alkyl groups, and R ₄ and R ₅ may be bonded to each other to form an alkylene ring.

In the general formula (3), X ₁ represents a single bond, an alkylene group, an oxygen atom or a sulfur atom, and R ₆ represents a substituted, unsubstituted alkyl group, a substituted or unsubstituted aromatic group. An electrophotographic photoreceptor used in the image forming apparatus according to claim 7. An image forming unit used in the image forming apparatus according to claim 7.

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