JP4360297B2 - Image forming apparatus and image forming method - Google Patents

Description

  The present invention relates to an image forming apparatus used as a color copying machine or a color printer, and an image forming method using the image forming apparatus.

  In recent years, color copying machines and color printers have a strong tendency to obtain color images. Color image forming methods with high practical value can be broadly classified by their commonly used names: intermediate transfer method, KNC method (method for creating a multicolor superimposed image on an electrophotographic photosensitive member and transferring them all at once), tandem method, etc. There is.

  Of course, since these are names given from different viewpoints, there are naturally, for example, an intermediate transfer system and a tandem system. A color image forming apparatus of the intermediate transfer system and tandem system (hereinafter, the tandem system is referred to as the intermediate transfer system and the tandem system) is known to obtain a high-quality full-color image. In this system, a toner image is formed on each organic photoconductor (hereinafter also referred to as a unit photoconductor) corresponding to yellow, magenta, cyan, and black, and a color superimposed image is formed on the intermediate transfer member. It is a batch transfer to a transfer material.

  When an organic photoreceptor (hereinafter simply referred to as a photoreceptor) is used as an electrophotographic photoreceptor in this intermediate transfer type color image forming apparatus, the following problems occur.

  That is, in the color image formation of the intermediate transfer method, there are two stages of transfer processes, a primary transfer in which the toner image is transferred from each organic photoconductor to the intermediate transfer body and a secondary transfer in which the toner image is transferred from the intermediate transfer body to the recording paper. Since there are two stages of cleaning, that is, cleaning of the organic photoreceptor after the primary transfer and cleaning of the intermediate body after the secondary transfer, image defects associated with defective transfer of toner images and image defects associated with cleaning are often apt to occur.

  In order to obtain high sensitivity and stable characteristics against changes in the greenhouse temperature, the conventional organic photoreceptor has a layer structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer. The constitution was such that a large amount of a low molecular weight charge transport material having a molecular weight of around 500 was contained. However, in organic photoreceptors having such a charge transport layer as a surface layer, due to wear deterioration due to repeated use and adhesion of foreign matter to the surface (adhesion of toner components and paper dust components), In the primary transfer of the toner image to the intermediate transfer body, the transferability of the toner changes, and image defects such as a decrease in image density and color shift (a large change in chromaticity) are likely to occur.

  As a method for solving such a problem, it has been reported to use a charge transport material having a large molecular weight. For example, an organic photoreceptor containing a charge transport material having a chemical structure of bisstyryl and a molecular weight of 1000 or more has been reported (Patent Document 1). However, when these charge transport materials are contained in the charge transport layer, the charge transport layer tends to have insufficient compatibility with the binder resin, the charge transport material is not uniformly dispersed, and the sensitivity is not sufficient. The charge transport layer on the surface is likely to be contaminated with the external additive component of the toner, and as a result, a dash mark (small comet-like streak image) is likely to occur, and the primary transfer of the toner image also changes, and color misregistration is likely to occur. . In addition, a photoreceptor using a charge transport material having a molecular weight of 3000 to 5000 has been reported (Patent Documents 2 and 3), but since the end group of this compound is not blocked, an increase in residual power is likely to occur. Further, compatibility with the binder resin has not been sufficiently solved.

Also, in recent electrophotographic image forming apparatuses, there is a tendency to be used as information equipment for printing out image information produced by a computer, and there are copying machines and printers capable of forming high-quality digital images. It has been demanded. Therefore, there is a need for developing means for faithfully developing the electrostatic latent image formed on the organic photoreceptor, and as one of the means, developing means is used for developing polymerized toner having a uniform shape factor and particle size distribution. (Patent Document 4). However, such a polymerized toner has strong adhesion to the above-mentioned organic photoreceptor and cleaning properties are likely to deteriorate. Therefore, in order to improve this, an inorganic external additive such as silica is added to the toner for practical use. . Therefore, these silica and the like are attached to the organic photoconductor to increase the occurrence of the above-mentioned dash marks and color shifts, and the characteristics of the polymerized toner improved by the shape factor and the particle size distribution are not sufficiently exhibited. The problem was found.
JP-A-3-149560 Japanese Patent Laid-Open No. 10-310635 JP-A-5-25102 JP 2000-214629 A

  The present invention has been made to solve the above problems. An object of the present invention is to provide an electrophotographic image of good color using an image forming apparatus using an intermediate transfer member, and particularly in the formation of a large number of color images, image defects such as dash marks described above are provided. At the same time, the change in the primary transferability of the toner from the photosensitive member to the intermediate transfer member is reduced, and the occurrence of image defects such as a decrease in image density and color misregistration is prevented. It is an object of the present invention to provide an electrophotographic image forming apparatus and an image forming method capable of obtaining a color image having a proper hue.

  In order to solve the above problems, the present inventors have studied the surface layer of the organic photoconductor to simultaneously solve the generation of dashes and the change in the primary transfer property of the toner from the photoconductor to the intermediate transfer member. We have found that it is important to use a resin that improves wear resistance for the charge transport layer that forms the surface layer of the organic photoreceptor, and to make it difficult for toner components and fat powder to adhere to the surface of the photoreceptor. Completed the invention. That is, the charge transport layer forming the surface layer may be a mixture of compounds having the same chemical structural unit and different molecular weights as the charge transport material, so that a large molecular weight charge transport material can be used as the average molecular weight. Even when an electrophotographic image is formed using a toner having good compatibility with the binder resin, the surface layer is not easily contaminated, and a uniform shape factor, particle size distribution, etc. The present inventors have found that the change in the primary transferability of toner from the toner to the intermediate transfer member can be reduced.

That is, the object of the present invention is achieved by adopting one of the following configurations.
(Claim 1)
A plurality of image forming units having at least developing means are provided, and each colored toner image is formed on the organic photoreceptor using toner whose color is changed for each of the plurality of image forming units, and the formed toner images are intermediately formed. A color toner image is formed by sequentially superimposing and transferring on a transfer body, the color toner image is collectively retransferred onto a recording material, and the retransferred color toner image is fixed to form a color image. In the image forming apparatus, the organophotoreceptor has a chemical structure of the following general formula (1), and the composition ratio of the maximum component compound of the mixed compound having a distribution based on n is x, the compound of the 2-position component An image forming apparatus comprising a mixed compound in which x + y is 94.3 % or less, where y is a composition ratio.

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。
（請求項２）
少なくとも有機感光体、帯電手段、露光手段、現像手段、転写手段、クリーニング手段を有する画像形成ユニットを複数配列して設け、該複数の画像形成ユニット毎に着色を変えたトナーを用いて有機感光体上に形成された各着色トナー像を中間転写体上に順次重ね合わせて転写してカラートナー像を形成し、該カラートナー像を記録材上に一括して再転写し、再転写されたカラートナー像を定着してカラー画像を形成する画像形成装置において、前記有機感光体が、下記一般式（１）の化学構造を有し、ｎを基準とした分布を持つ混合化合物の最大成分の化合物の組成比をｘ、２位成分の化合物の組成比をｙとすると、ｘ＋ｙが９４．３％以下の混合化合物を含有することを特徴とする画像形成装置。
一般式（１）
Ｘ−（ＣＴＭ基）_ｎ−Ｙ
上記一般式（１）中、ＣＴＭ基、Ｘ、Ｙは下記の一般式Ａの化学構造を表す。又、ｎは０〜１０の整数を示す。

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。
（請求項３）
一般式（１）のｘ＋ｙが下記の範囲にあることを特徴とする請求項１又は２に記載の画像形成装置。 General formula (1)
X- (CTM group) _n -Y
In the general formula (1), the CTM group, 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.
(Claim 2)
A plurality of image forming units having at least an organic photoconductor, a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit are arranged, and an organic photoconductor using a toner whose color is changed for each of the plurality of image forming units. Each colored toner image formed thereon is sequentially superimposed and transferred onto an intermediate transfer member to form a color toner image, and the color toner image is collectively re-transferred onto a recording material, and the re-transferred color In an image forming apparatus for fixing a toner image to form a color image, the organic photoreceptor has a chemical structure represented by the following general formula (1) and has a distribution based on n and is the largest component compound compound An image forming apparatus comprising a mixed compound in which x + y is 94.3% or less, where x is a composition ratio of a 2-position compound and y is a composition ratio of a compound at the 2-position.
General formula (1)
X- (CTM group) _n -Y
In the general formula (1), the CTM group, 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.
(Claim 3)
The image forming apparatus according to claim 1, wherein x + y in the general formula (1) is in the following range.

30% ≦ x + y ≦ 9 4.3 %

(Claim 4 )
The image forming apparatus according to claim 1, wherein the divalent group containing the triarylamine group of A is a group of the following general formula (4).

In General Formula (4), Ar ₃ represents a substituted or unsubstituted monovalent aromatic group.
(Claim 5 )
The image forming apparatus according to claim 4 , wherein the Ar ₃ is a group of the following general formula (5).

In the general formula (5), R ₃₁ , R ₃₂ , R ₃₃ , R ₃₄ and R ₃₅ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. However, at least one of R ₃₁ and R ₃₅ is an alkyl group having 1 to 4 carbon atoms.
(Claim 6 )
The image forming apparatus according to claim 1, wherein the divalent group containing a triarylamine group of A is a group of the following general formula (6).

In General Formula (6), X ₂ is a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted divalent aromatic group, and Ar ₄ and Ar ₅ are substituted or unsubstituted monovalent aromatic groups. Indicates.

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。
（請求項１１）
少なくとも現像手段を有する画像形成ユニットを複数有し、該複数の画像形成ユニット毎に着色を変えたトナーを用いて有機感光体上に各着色トナー像を形成し、該形成されたトナー像を中間転写体上に順次重ね合わせて転写してカラートナー像を形成し、該カラートナー像を記録材上に一括して再転写し、再転写されたカラートナー像を定着してカラー画像を形成する画像形成装置において、前記有機感光体が、下記一般式（１）の化学構造を有し、ｎを基準とした分布を持つ混合化合物の最大成分の化合物の組成比をｘ、２位成分の化合物の組成比をｙとすると、ｘ＋ｙが９９％以下の混合化合物を含有し、前記現像手段が角がないトナー粒子が５０個数％以上であるトナーを含有することを特徴とする画像形成装置。
一般式（１）
Ｘ−（ＣＴＭ基）_ｎ−Ｙ
上記一般式（１）中、ＣＴＭ基、Ｘ、Ｙは下記の一般式Ａの化学構造を表す。又、ｎは０〜１０の整数を示す。

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。
（請求項１２）
少なくとも現像手段を有する画像形成ユニットを複数有し、該複数の画像形成ユニット毎に着色を変えたトナーを用いて有機感光体上に各着色トナー像を形成し、該形成されたトナー像を中間転写体上に順次重ね合わせて転写してカラートナー像を形成し、該カラートナー像を記録材上に一括して再転写し、再転写されたカラートナー像を定着してカラー画像を形成する画像形成装置において、前記有機感光体が、下記一般式（１）の化学構造を有し、ｎを基準とした分布を持つ混合化合物の最大成分の化合物の組成比をｘ、２位成分の化合物の組成比をｙとすると、ｘ＋ｙが９４．３％以下の混合化合物を含有し、前記現像手段が、トナー粒子の粒径をＤ（μｍ）とするとき、自然対数ｌｎＤを横軸にとり、この横軸を０．２３間隔で複数の階級に分けた個数基準の粒度分布を示すヒストグラムにおける最頻階級に含まれるトナー粒子の相対度数（ｍ_１）と、前記最頻階級の次に頻度の高い階級に含まれるトナー粒子の相対度数（ｍ_２）との和（Ｍ）が７０％以上であるトナーを含有することを特徴とする画像形成装置。
一般式（１）
Ｘ−（ＣＴＭ基）_ｎ−Ｙ
上記一般式（１）中、ＣＴＭ基、Ｘ、Ｙは下記の一般式Ａの化学構造を表す。又、ｎは０〜１０の整数を示す。

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。
（請求項１３）
少なくとも現像手段を有する画像形成ユニットを複数有し、該複数の画像形成ユニット毎に着色を変えたトナーを用いて有機感光体上に各着色トナー像を形成し、該形成されたトナー像を中間転写体上に順次重ね合わせて転写してカラートナー像を形成し、該カラートナー像を記録材上に一括して再転写し、再転写されたカラートナー像を定着してカラー画像を形成する画像形成装置において、前記有機感光体が、下記一般式（１）の化学構造を有し、ｎを基準とした分布を持つ混合化合物の最大成分の化合物の組成比をｘ、２位成分の化合物の組成比をｙとすると、ｘ＋ｙが９４．３％以下の混合化合物を含有し、前記現像手段が、トナー粒子の形状係数の変動係数が１６％以下、個数粒度分布における個数変動係数が２７％以下であるトナーを含有することを特徴とする画像形成装置。
一般式（１）
Ｘ−（ＣＴＭ基）_ｎ−Ｙ
上記一般式（１）中、ＣＴＭ基、Ｘ、Ｙは下記の一般式Ａの化学構造を表す。又、ｎは０〜１０の整数を示す。

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。
（請求項１４）
少なくとも請求項１〜１３のいずれか１項に記載の画像形成装置を用いて電子写真画像を形成することを特徴とする画像形成方法。 (Claim 7)
The organic photoreceptor has a layer structure in which a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material are laminated on a conductive support, and the charge transport layer is represented by the general formula (1) X + y is 94.3% or less, where x is the composition ratio of the compound of the largest component of the mixed compound having the chemical structure and distribution based on n, and y is the composition ratio of the compound of the 2-position component. The image forming apparatus according to claim 1, further comprising a compound.
(Claim 8)
The image forming apparatus according to claim 7, wherein the charge transport layer forms a surface layer of an organic photoreceptor.
(Claim 9)
9. The image forming apparatus according to claim 7, further comprising an intermediate layer between the conductive support and the charge generation layer.
(Claim 10)
A plurality of image forming units having at least developing means are provided, and each colored toner image is formed on the organic photoreceptor using toner whose color is changed for each of the plurality of image forming units, and the formed toner images are intermediately formed. A color toner image is formed by sequentially superimposing and transferring on a transfer body, the color toner image is collectively retransferred onto a recording material, and the retransferred color toner image is fixed to form a color image. In the image forming apparatus, the organophotoreceptor has a chemical structure of the following general formula (1), and the composition ratio of the maximum component compound of the mixed compound having a distribution based on n is x, the compound of the 2-position component Where the composition ratio of y is a toner that contains a mixed compound having x + y of 94.3% or less, and the developing means has 65% or more of toner particles having a shape factor in the range of 1.2 to 1.6. It is characterized by containing Image forming apparatus.
General formula (1)
X- (CTM group) _n -Y
In the general formula (1), the CTM group, 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.
(Claim 11)
A plurality of image forming units having at least developing means are provided, and each colored toner image is formed on the organic photoreceptor using toner whose color is changed for each of the plurality of image forming units, and the formed toner images are intermediately formed. A color toner image is formed by sequentially superimposing and transferring on a transfer body, the color toner image is collectively retransferred onto a recording material, and the retransferred color toner image is fixed to form a color image. In the image forming apparatus, the organophotoreceptor has a chemical structure of the following general formula (1), and the composition ratio of the maximum component compound of the mixed compound having a distribution based on n is x, the compound of the 2-position component An image forming apparatus comprising: a mixed compound containing x + y of 99% or less, wherein the developing means contains 50% by number or more of toner particles having no corners.
General formula (1)
X- (CTM group) _n -Y
In the general formula (1), the CTM group, 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.
(Claim 12)
A plurality of image forming units having at least developing means are provided, and each colored toner image is formed on the organic photoreceptor using toner whose color is changed for each of the plurality of image forming units, and the formed toner images are intermediately formed. A color toner image is formed by sequentially superimposing and transferring on a transfer body, the color toner image is collectively retransferred onto a recording material, and the retransferred color toner image is fixed to form a color image. In the image forming apparatus, the organophotoreceptor has a chemical structure of the following general formula (1), and the composition ratio of the maximum component compound of the mixed compound having a distribution based on n is x, the compound of the 2-position component Where x + y is 94.3% or less of the mixed compound, and the developing means takes the natural logarithm lnD on the horizontal axis when the toner particle diameter is D (μm). Multiple horizontal axes at intervals of 0.23 A relative frequency of toner particles included in the most frequent class in the histogram showing a particle size distribution of number-based divided into classes (m _1), the relative frequency of the toner particles contained in the following frequent the rank of the modal class ( An image forming apparatus comprising a toner having a sum (M) of m ₂ ) of 70% or more.
General formula (1)
X- (CTM group) _n -Y
In the general formula (1), the CTM group, 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.
(Claim 13)
A plurality of image forming units having at least developing means are provided, and each colored toner image is formed on the organic photoreceptor using toner whose color is changed for each of the plurality of image forming units, and the formed toner images are intermediately formed. A color toner image is formed by sequentially superimposing and transferring on a transfer body, the color toner image is collectively retransferred onto a recording material, and the retransferred color toner image is fixed to form a color image. In the image forming apparatus, the organophotoreceptor has a chemical structure of the following general formula (1), and the composition ratio of the maximum component compound of the mixed compound having a distribution based on n is x, the compound of the 2-position component Is a mixed compound having x + y of 94.3% or less, and the developing means has a variation coefficient of the shape factor of toner particles of 16% or less and a number variation coefficient of 27% in the number particle size distribution. The following An image forming apparatus characterized by containing over.
General formula (1)
X- (CTM group) _n -Y
In the general formula (1), the CTM group, 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.
(Claim 14)
An image forming method comprising forming an electrophotographic image using at least the image forming apparatus according to claim 1.

  By using the present invention, it is possible to improve the primary transferability of an electrophotographic toner using an intermediate transfer member, and to reduce the change in the primary transferability of the toner between the initial use of the photoreceptor and after repeated use, and the image density An image forming apparatus and an image forming apparatus of an electrophotographic system that can prevent the occurrence of image defects such as deterioration of color and color misregistration, and can also prevent the generation of dash marks, and reproduce a color image with good sharpness and a vivid hue It is to provide a method.

The image forming apparatus of the present invention has a plurality of image forming units having at least developing means, and forms each colored toner image on the organic photoreceptor using toner whose color is changed for each of the plurality of image forming units. The formed toner images are sequentially superimposed and transferred on the intermediate transfer member to form a color toner image, and the color toner image is collectively re-transferred onto the recording material, and the re-transferred color toner image is obtained. In an image forming apparatus for fixing and forming a color image, the organic photoreceptor has a chemical structure of the general formula (1), and a composition ratio of a compound as a maximum component of a mixed compound having a distribution based on n Where x is the composition ratio of the 2-position compound, and x + y is a mixed compound of 94.3 % or less.

The image forming apparatus of the present invention is provided with a plurality of image forming units having at least an organic photoreceptor, a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit, and each of the plurality of image forming units is colored. Each colored toner image formed on the organic photoreceptor using the toner with different colors is sequentially superimposed and transferred on the intermediate transfer member to form a color toner image, and the color toner image is collectively put on the recording material. In the image forming apparatus for forming a color image by fixing the re-transferred color toner image, the organic photoreceptor has the chemical structure of the general formula (1), and n is a reference. When the composition ratio of the compound of the maximum component of the mixed compound having a distribution is x and the composition ratio of the compound of the 2-position component is y, x + y is a mixture compound of 94.3 % or less.

  The image forming apparatus of the present invention can improve the primary transferability of the toner image from the photosensitive member to the intermediate transfer member in the intermediate transfer system by using the above-described organic photosensitive member, and the target achieved in the initial use of the photosensitive member. Even on photoconductors where the performance has been sufficiently used repeatedly, it is fully achieved, preventing the occurrence of image defects such as image density reduction and color misregistration, and at the same time preventing the occurrence of dash marks, and the sharpness is good A vivid color image can be provided.

  The configuration of the image forming apparatus of the present invention will be described below.

The organophotoreceptor used in the image forming apparatus of the present invention has a 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 2-position. When the composition ratio of the component compounds is y, x + y contains a mixed compound of 94.3 % or less.

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 a hydrogen atom, a halogen atom, or a monovalent organic group. N is an integer of 0 to 10 (provided that when X and Y are both hydrogen atoms or halogen atoms (one of X and Y may be a hydrogen atom and the other may be a halogen atom), n is an integer of 1 to 10) ).

In the present invention, when the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the general formula (1) and having a distribution based on n is x, the composition ratio of the compound of the 2-position component is y. , X + y containing 99% or less of a mixed compound is a mixture of compounds of general formula (1) and having different numbers of chain structures of CTM groups, that is, charge transporting groups (= n as a reference) Compound having a distribution), among the mixed compounds (mixed compounds), x is the composition ratio (existence ratio) of the compound having the largest abundance ratio, and x is the composition ratio (abundance ratio) of the compound at the 2-position component. ) Is y, x + y is 94.3 % or less, and this means that the mixed compound contains at least three compounds of the general formula (1) having different n. By using such a mixed compound as a charge transport material, the compatibility with solvents and binder resins is remarkably improved, and the target performance such as sensitivity achieved in the initial use of the photoreceptor is sufficiently used repeatedly. This is also achieved sufficiently in the body, and at the same time, the generation of dash marks can be prevented and the primary transfer of the toner image from the photoconductor to the intermediate transfer body in the intermediate transfer system can be improved. The occurrence of image defects such as the above can be prevented, and a color image with good sharpness and a vivid hue can be provided.

  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.

When the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the general formula (1) and having a distribution based on n is x, the composition ratio of the compound of the 2-position component is y, and x + y is 9 Although various chemical structures can be considered as specific examples of the mixed compound of 4.3 % 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 a monovalent substituted or unsubstituted aromatic group, Ar ₂ represents a divalent substituted, unsubstituted aromatic group, divalent furan group or thiophene group, or the following general formula (2) indicates, R ₁ to R ₃ is a hydrogen atom, a substituted or unsubstituted alkyl group, a monovalent substituent indicates a non-substituted aromatic group, a is a divalent group containing triarylamine group Or the group of the following general formula (3) is shown. 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 examples of the general formula A ′ are also exemplified as the chemical structure examples of the general formula (1) of the present invention.

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, a mixed compound having a distribution based on n in each chemical structure, x = y is 99% or less, where x is the composition ratio of the compound of the largest component, and y is the composition ratio of the compound of the 2-position component. Is used as a charge transport material.

  Below, the synthesis example of the said mixed compound (general formula A) of this invention 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 of the present invention is defined by the area ratio of each component after composition separation by 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 of the present invention.

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, a mixed compound having a distribution based on n in each chemical structure, x = y is 99% or less, where x is the composition ratio of the compound of the largest component, and y is the composition ratio of the compound of the 2-position component. Is used as a charge transport material.

  Below, the synthesis example of the said mixed compound (general formula B) of this invention 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) of this invention 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.

  A compound having the structure of the general formula (1) of the present invention and having a distribution based on n, wherein the composition ratio of the compound of the maximum component of the compound is x, and the composition of the compound of the 2-position component When the ratio is y, x + y contains a mixed compound of 99% or less, and x + y is preferably 30% to 99%, more preferably 45% to 90%. When x + y is less than 30%, the distribution of n is too wide, the molecular weight tends to increase, and the solubility and compatibility with the solvent and binder resin tend to deteriorate. On the other hand, when the ratio is larger than 99%, the solubility and compatibility with the solvent and the binder resin are likely to be similarly deteriorated when the low molecular weight ratio is decreased.

  Moreover, in the said general formula, although n is 0-10, n may contain the component 11 or more. That is, the maximum component and the second-position component exist between n = 0 and 10, and x + y may be 99% or less.

  The average molecular weight of the mixed compound of the present invention is preferably 650 to 2500, and more preferably 800 to 2300. The average molecular weight is expressed in terms of polystyrene-equivalent weight average molecular weight. When the average molecular weight exceeds 2500, the solvent solubility decreases, and the compatibility of the charge transport layer with the binder resin deteriorates. As a result, the dispersibility of the charge transport material is reduced. The electrophotographic characteristics such as sensitivity and uniform chargeability are significantly reduced. On the other hand, if it is less than 650, film physical properties such as the glass transition point (Tg) of the charge transport layer are lowered, and black spots and periodic image defects are likely to occur.

  Next, the layer structure of an electrophotographic photoreceptor using the mixed compound of the present invention as described above as a charge transport material, particularly an organic photoreceptor will be described.

  The organic photoconductor of the present invention means an electrophotographic photoconductor constituted by giving an organic compound at least one of a charge generation function and a charge transport function indispensable for the constitution of the electrophotographic photoconductor. It contains all known organic electrophotographic photoreceptors such as a photoreceptor composed of an organic charge generating material or an organic charge transport material, a photoreceptor composed of a polymer complex with a charge generating function and a charge transport function.

  The constitution of the organic photoreceptor used in the present invention is described below.

Conductive Support The conductive support used for the photoreceptor may be either a sheet or a cylinder, but a cylindrical conductive support is preferred for designing an 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. Exceeding the range of straightness and shake makes it difficult to form a good image.

As the conductive material, 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.

  As the conductive support used in the present invention, one having an alumite film that has been sealed on the surface thereof may be used. 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.

Intermediate layer In the present invention, an intermediate layer having a barrier function may be provided between the conductive support and the photosensitive 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 support and the photosensitive layer. Including) 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 subbing resins, a polyamide resin is preferable as a resin capable of reducing the increase in residual potential due to repeated use. The film thickness of the intermediate layer using these resins is preferably 0.01 to 0.5 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. As for the film thickness of the intermediate | middle layer using curable metal resin, 0.1-2 micrometers is preferable.

  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.

  The N-type semiconducting fine particles are fine particles having the property of using conductive carriers as electrons. That is, the property that the conductive carrier is an electron is that the N-type semiconducting fine particles are contained in an insulating binder to effectively block hole injection from the substrate, and to convert electrons from the photosensitive layer into electrons. On the other hand, it has the property which does not show blocking property.

  Here, a method for discriminating N-type semiconductor particles will be described.

  An intermediate layer having a thickness of 5 μm is formed on the conductive support (the intermediate layer is formed using a dispersion in which 50% by mass of particles are dispersed in the binder resin constituting the intermediate layer). The intermediate layer is negatively charged and the light attenuation characteristics are evaluated. In addition, the light attenuation characteristics are similarly evaluated by charging to positive polarity.

  N-type semiconductive particles are particles that are dispersed in the intermediate layer in the above evaluation when the light attenuation when charged negatively is greater than the light attenuation when charged positively. It is called semiconductive particle.

Specific examples of the N-type semiconducting fine particles include fine particles of titanium oxide (TiO ₂ ), zinc oxide (ZnO), tin oxide (SnO ₂ ), etc. In the present invention, titanium oxide is particularly preferably used. It is done.

  The average particle diameter of the N-type semiconducting fine particles used in the present invention is preferably in the range of 10 nm to 500 nm in the number average primary particle diameter, more preferably 10 nm to 200 nm, and particularly preferably 15 nm to 50 nm. .

  The intermediate layer using N-type semiconducting fine particles whose number average primary particle size is within the above range can be finely dispersed in the layer, has sufficient potential stability, and generates black spots. Has a prevention function.

  For example, in the case of titanium oxide, the number-average primary particle size of the N-type semiconducting fine particles is magnified 10,000 times by observation with a transmission electron microscope, and 100 particles are randomly observed as primary particles. It is measured as the number average diameter.

  The shape of the N-type semiconducting fine particles used in the present invention includes dendritic, needle-like, and granular shapes. For example, in the case of titanium oxide particles, the N-type semiconductive fine particles have a crystalline form. There are anatase type, rutile type and amorphous type, but any crystal type may be used, or two or more crystal types may be mixed and used. Of these, the rutile type is the best.

  One of the hydrophobizing surface treatments performed on the N-type semiconducting fine particles is a plurality of surface treatments, and the last surface treatment is a surface treatment with a reactive organosilicon compound. Is to do. In addition, at least one of the surface treatments is at least one surface treatment selected from alumina, silica, and zirconia, and finally the surface treatment of the reactive organosilicon compound is performed. It is preferable.

  Alumina treatment, silica treatment, and zirconia treatment are treatments for precipitating alumina, silica, or zirconia on the surface of the N-type semiconducting fine particles. Zirconia hydrates are also included. The surface treatment of the reactive organosilicon compound means using a reactive organosilicon compound in the treatment liquid.

  In this way, the surface treatment of the N-type semiconductive fine particles such as titanium oxide particles was performed at least twice, so that the surface of the N-type semiconductive fine particles was uniformly coated (treated), and the surface treatment was performed. When N-type semiconducting fine particles are used in the intermediate layer, a good photoconductor having good dispersibility of N-type semiconductive fine particles such as titanium oxide particles in the intermediate layer and causing no image defects such as black spots. You can get it.

Photosensitive layer The photosensitive layer configuration of the photoreceptor of the present invention may be a single-layer photosensitive layer configuration in which the intermediate layer has a charge generation function and a charge transport function in one layer, but more preferably the function of the photosensitive layer. The charge generation layer (CGL) and the charge transport layer (CTL) may be separated from each other. By adopting a configuration in which the functions are separated, an increase in the residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negatively charged photoconductor, it is preferable that a charge generation layer (CGL) is formed on the intermediate layer, and a charge transport layer (CTL) is formed thereon. In the positively charged photoconductor, the order of the layer configuration is the reverse of that in the negatively charged photoconductor. The most preferred photosensitive layer structure of the present invention is a negatively charged photoreceptor structure having the function separation structure.

  The structure of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below.

Charge generation layer The charge generation layer contains a charge generation material (CGM). Other substances may contain a binder resin and other 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 is used as the CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, phenoxy resin, and the like. Can be mentioned. 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 that forms a film by dispersing CTM. Other substances may contain additives such as antioxidants as necessary.

  As the charge transport material (CTM), a mixture of two or more compounds having an average molecular weight of 2500 or less and different n in the general formula (1) is used. Further, for example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, and the like can be used in combination with a mixture of two or more kinds of compounds having different n in the general formula (1). These charge transport materials are usually dissolved in a suitable binder resin to form a layer.

  Examples of the resin used for 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, and polycarbonate. Resin, silicone resin, melamine resin, and copolymer resin containing two or more of repeating unit structures of these resins. In addition to these insulating resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used.

  Most preferred as a binder for these CTLs is a polycarbonate resin. The polycarbonate resin is most 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 the action of oxygen on auto-oxidizing substances existing in the electrophotographic photosensitive member or on the surface of the electrophotographic photosensitive member under conditions of light, heat, and discharge. It is also a substance having a suppressing property. Typical examples include the following compound groups.

  The charge transport layer may be composed of two or more layers. In this case, the charge transport layer on the surface may satisfy the configuration of the present invention. The thickness of the charge transport layer is preferably 10 to 40 μm.

  In the above, the most preferable layer structure of the photoreceptor of the present invention is exemplified, but in the present invention, a photoreceptor layer structure other than the above may be used.

  As a solvent or dispersion medium used for forming a layer such as a photosensitive layer, an intermediate layer, and a surface 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, dimethyl sulfoxide, methyl cellosolve, etc. And the like. 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.

  Next, as a coating processing method for producing the organic electrophotographic photosensitive member, a coating processing method such as dip coating, spray coating, circular amount regulation type coating, etc. is used. In order to prevent the film from being dissolved as much as possible, and 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 (circular slide hopper type is a typical example). It is most preferable to use the circular amount regulation type coating method for the protective layer. The circular amount regulation type coating is described in detail in, for example, Japanese Patent Application Laid-Open No. 58-189061.

  In addition, the present invention employs an image forming apparatus that uses the organic photoreceptor and a toner having a uniform shape factor and a sharp particle size distribution as described below, thereby reducing the halftone image due to dash marks and scratches. It is possible to prevent the occurrence of spots and to produce a good electrophotographic image.

(1) Toner containing 65% by number or more of toner particles having a shape factor in the range of 1.2 to 1.6 The toner having such characteristics is the shape of toner particles (the toner particles mean individual particles). Is close to a true sphere and has a similar shape, the toner has uniform charging characteristics and has a property of faithfully developing a latent image on the photoreceptor. For this reason, there is a large tendency to more clearly reproduce the occurrence of dash marks due to external additives adhering to the photoreceptor, or the occurrence of spots, but toner particles having a shape factor in the range of 1.2 to 1.6 By using the toner containing 65% by number or more in combination with the above-described organic photoreceptor of the present invention, it is possible to prevent dash marks and spots, and it is possible to produce a good electrophotographic image with no noticeable color shift.

  On the other hand, when the number of toner particles having a shape factor in the range of 1.2 to 1.6 is less than 65% by number, the toner charge amount distribution becomes large, and as a result, overcharged toner particles are likely to be generated. These adhere firmly to the surface of the photoconductor and easily generate dash marks.

(2) Toner containing 50% by number or more of toner particles having no corners Toner particles having no corners are toner particles that substantially do not have protrusions that concentrate charges or that tend to be crushed by stress. When the ratio of toner particles without corners is 50% by number or more, more preferably 70% by number or more, generation of fine particles is less likely to occur due to stress with the developer conveying member and the like. Occurrence of a dash mark due to adhesion of toner to the photoreceptor can be prevented. That is, when used in combination with the photoreceptor of the present invention, it is possible to form a good electrophotographic image in which a dash mark is hardly generated and color misregistration is not noticeable over a long period of time. For this purpose, the proportion of toner particles without corners is preferably 50% by number or more, more preferably 70% by number or more.

(3) When the particle diameter of toner particles is D (μm), the horizontal axis represents the natural logarithm lnD, and the horizontal axis represents a number-based particle size distribution divided into a plurality of classes at intervals of 0.23. The sum (M) of the relative frequency (m ₁ ) of the toner particles contained in the most frequent class and the relative frequency (m ₂ ) of the toner particles contained in the next most frequent class is 70% or more. The toner contained The toner having a relative frequency (m ₁ ) and a sum (M) of the relative frequency (m ₂ ) of 70% or more makes the particle size distribution of the toner particles constituting the toner sharp, and the charging property is improved. As a result, it is possible to form a stable toner image, and as a result, by using it together with the photoconductor of the present invention, it is possible to prevent scratches, dashes and spots, and to produce a good electrophotographic image with no noticeable color shift. I can do it.

(4) Toner in which the number variation coefficient in the number particle size distribution of the toner particles is 27% or less and the variation coefficient of the toner particle shape factor is 16% or less The variation coefficient of the toner shape factor is 16% or less, and By using a toner having a number variation coefficient of 27% or less in the number particle size distribution, stable charging characteristics can be imparted to the toner. By using such a toner in combination with the above-described photoreceptor of the present invention, scratches, dash marks, and spots can be prevented, and a good electrophotographic image with no noticeable color shift can be produced. The number variation coefficient of the toner is 27% or less, preferably 25% or less. The variation coefficient of the shape factor of the toner particles is 16% or less, more preferably 14% or less.

  The toner of the present invention can be used in combination with the organic photoreceptor of the present invention as long as it satisfies at least one of the above conditions (1), (2), (3), and (4). In addition, scratches, dashes and spots can be prevented, and a good electrophotographic image can be produced. Further, among the conditions (1), (2), (3) and (4), (2) The toner satisfying at least one of the above condition (1) or (3) is more preferable, and the toner satisfying all the above conditions (1), (2), (3), and (4) is most preferable.

  The toner preferably has a number average primary particle size of 3 to 8 μm. When the toner particles are formed by a polymerization method, the particle size can be controlled by the concentration of the aggregating agent, the amount of the organic solvent added, the fusing time, and further the composition of the polymer itself.

  When the number average particle diameter is 3 to 8 μm, it is possible to reduce the presence of excessively adhering toner or low adhering toner on the developer conveying member in the fixing step, and developability over a long period of time. And the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines and dots is improved.

  The shape factor of the toner is expressed by the following formula and indicates the degree of roundness of the toner particles.

Shape factor = ((maximum diameter / 2) ² × π) / projection area Here, the maximum diameter is the distance between the parallel lines when the projected image of toner particles on a plane is sandwiched between two parallel lines. The maximum particle width. The projected area refers to the area of the projected image of the toner particles on the plane.

  This shape factor is obtained by taking a photograph in which toner particles are magnified 2000 times with a scanning electron microscope, and then analyzing a photographic image using “SCANNING IMAGE ANALYZER” (manufactured by JEOL Ltd.) based on this photograph. Was measured. At this time, the shape factor of the present invention was measured by the above formula using 100 toner particles.

  In the toner of the present invention, the number of toner particles having a shape factor in the range of 1.2 to 1.6 is 65% by number or more, preferably 70% by number or more.

  The method for controlling the shape factor is not particularly limited. For example, a method in which toner particles are sprayed into a hot air stream, a method in which toner particles are repeatedly applied with mechanical energy due to impact force in a gas phase, or a method in which a toner is not dissolved in a solvent and a swirl flow is applied. However, in the present invention, it is preferable to produce a shape factor and the like within the scope of the present invention using a polymerized toner produced by a polymerization method.

  The variation coefficient of the toner shape factor is calculated from the following equation.

Coefficient of variation = [S / K] x 100 (%)
[In the formula, S represents the standard deviation of the shape factor of 100 toner particles, and K represents the average value of the shape factor. ]
In order to control the shape factor of the toner and the coefficient of variation of the shape factor uniformly without any lot variation, the production process of the polymerized toner, that is, the step of polymerizing, fusing and controlling the shape of the resin particles (polymer particles) The proper process end time may be determined while monitoring the characteristics of the toner particles (colored particles) being formed.

  Monitoring means that a measuring device is incorporated in-line, and process conditions are controlled based on the measurement result. In other words, in the case of a polymerization method toner that is formed by incorporating measurement such as shape in-line, for example, by associating or fusing resin particles in an aqueous medium, the shape and particle size are measured while performing sequential sampling in the fusing step. The reaction is stopped when the desired shape is obtained.

  Although it does not specifically limit as a monitoring method, The flow type particle image analyzer FPIA-2000 (made by Toa Medical Electronics Co., Ltd.) can be used. This apparatus is suitable because the shape can be monitored by performing image processing in real time while passing the sample liquid. That is, a pump or the like is used from the reaction field and is constantly monitored to measure the shape and the like, and the reaction is stopped when the desired shape is obtained.

  The number particle size distribution and the number variation coefficient of the toner are measured by a Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter). In the present invention, a Coulter Multisizer is used, and an interface (manufactured by Nikkaki Co., Ltd.) that outputs a particle size distribution and a personal computer are connected. The aperture used in the Coulter Multisizer was 100 μm, and the volume and number of toners of 2 μm or more were measured to calculate the particle size distribution and average particle size. The number particle size distribution represents the relative frequency of the toner particles with respect to the particle size, and the number average particle size represents the median diameter in the number particle size distribution.

  The number variation coefficient in the toner number particle size distribution is calculated from the following equation.

Number variation coefficient = [S / Dn] × 100 (%)
[In the formula, S represents the standard deviation in the number particle size distribution, and Dn represents the number average particle size (μm). ]
The method for controlling the number variation coefficient is not particularly limited. For example, a method of classifying toner particles by wind force can be used, but classification in a liquid is effective for reducing the number variation coefficient. As a method of classifying in this liquid, there is a method of separating and collecting toner particles according to a difference in sedimentation speed caused by a difference in toner particle diameter by using a centrifuge and controlling the rotation speed.

  In particular, when a toner is produced by a suspension polymerization method, a classification operation is indispensable in order to make the number variation coefficient in the number particle size distribution 27% or less. In the suspension polymerization method, it is necessary to disperse a polymerizable monomer in an oil droplet having a desired size as a toner in an aqueous medium before polymerization. That is, mechanical shearing with a homomixer or homogenizer is repeated for large oil droplets of a polymerizable monomer to reduce the oil droplets to the size of toner particles. In the method using shearing, the number particle size distribution of the obtained oil droplets is wide, and therefore the particle size distribution of the toner obtained by polymerizing the oil droplets is also wide. For this reason, classification operation is essential.

  The toner particles having no corners are toner particles that do not substantially have a protrusion that concentrates charges or a protrusion that easily wears due to stress. That is, as shown in FIG. When the major axis of the particle T is L, a circle C having a radius (L / 10) is rolled into the toner T when the inner side is rolled in contact with the peripheral line of the toner particle T at one point. The case where the toner particles do not substantially protrude outside is referred to as “toner particles having no corners”. “A case where the protrusion does not substantially protrude” refers to a case where the protrusion having the protruding circle is one or less. The “major diameter of toner particles” refers to the width of a particle that maximizes the interval between the parallel lines when the projected image of the toner particles on a plane is sandwiched between two parallel lines. FIGS. 3B and 3C show projection images of toner particles having corners.

  The measurement of toner without corners was performed as follows. First, an enlarged photograph of the toner particles is taken with a scanning electron microscope, and further enlarged to obtain a 15,000 times photographic image. The photographic image is then measured for the presence or absence of the corners. This measurement was performed on 100 toner particles.

  A method for obtaining toner having no corners is not particularly limited. For example, as described above as a method for controlling the shape factor, a method in which toner particles are sprayed into a hot air stream, a method in which toner particles are repeatedly applied with mechanical energy by impact force in a gas phase, or a toner is dissolved. It can be obtained by adding in a solvent that does not, and applying a swirling flow. However, in consideration of production cost and energy cost, a polymerized toner by a polymerization method is preferable.

  For example, in a polymerization toner formed by associating or fusing resin particles, the fusing particle surface has many irregularities at the fusing stop stage, and the surface is not smooth, but the temperature in the shape control step, By making the conditions such as the number of revolutions of the stirring blade and the stirring time appropriate, a toner having no corners can be obtained. These conditions vary depending on the physical properties of the resin particles. For example, by setting the number of revolutions to be higher than the glass transition temperature of the resin particles, the surface becomes smooth and a toner having no corners can be formed.

  The toner of the present invention preferably has a number average particle diameter of 3 to 8 μm. When the toner particles are formed by a polymerization method, the particle size can be controlled by the concentration of the aggregating agent, the amount of the organic solvent added, the fusing time, and further the composition of the polymer itself.

As the polymerized toner preferably used in the present invention, when the particle diameter of the toner particle is D (μm), the natural logarithm lnD is taken on the horizontal axis, and the horizontal axis is divided into a plurality of classes at intervals of 0.23. In the histogram showing the particle size distribution, the relative frequency (m ₁ ) of the toner particles included in the most frequent class and the relative frequency (m ₂ ) of the toner particles included in the most frequent class after the most frequent class. A toner having a sum (M) of 70% or more is preferable.

When the sum (M) of the relative frequency (m ₁ ) and the relative frequency (m ₂ ) is 70% or more, the dispersion of the particle size distribution of the toner particles is narrowed, so that the toner is used in the image forming process. The occurrence of selective development can be reliably suppressed.

  In the present invention, the histogram showing the particle size distribution based on the number is a natural logarithm lnD (D: particle size of individual toner particles) having a plurality of classes (0 to 0.23: 0.23) at intervals of 0.23. 0.46: 0.46-0.69: 0.69-0.92: 0.92-1.15: 1.15-1.38: 1.38-1.61: 1.61-1. 84: 1.84 to 2.07: 2.07 to 2.30: 2.30 to 2.53: 2.53 to 2.76, and so on). This histogram is prepared by transferring the particle size data of a sample measured by a Coulter Multisizer to a computer via an I / O unit according to the following conditions and using the particle size distribution analysis program in the computer. is there.

〔Measurement condition〕
(1) Aperture: 100 μm
(2) Sample preparation method: Electrolyte [ISOTON R-11 (manufactured by Coulter Scientific Japan)] 50-100 ml, an appropriate amount of a surfactant (neutral detergent) was added and stirred, and a measurement sample 10-20 mg was added thereto. Add This system is prepared by dispersing for 1 minute with an ultrasonic disperser.

The method for controlling the shape factor and the like of the present invention is preferable in that the polymerized toner is simple as a production method and the characteristics are easily controlled as compared with the pulverized toner.
The term “polymerized toner” means a toner in which a toner binder resin is formed and the toner shape is formed by polymerization of a raw material monomer of the binder resin and, if necessary, subsequent chemical treatment. More specifically, it means a toner formed through a polymerization reaction such as suspension polymerization or emulsion polymerization, and if necessary, a step of fusing particles between them.
Since the polymerized toner is produced by uniformly dispersing the raw material monomers in an aqueous system and then producing the toner, a toner having a uniform toner particle size distribution and shape can be obtained.

  The polymerized toner is produced by emulsion polymerization of monomers in a suspension polymerization method or in a solution to which an emulsion of necessary additives is added to produce fine polymer particles, and then an organic solvent, an aggregating agent, etc. It can manufacture by the method of adding and associating. A method of preparing by mixing with a dispersion liquid such as a release agent and a colorant necessary for the composition of the toner at the time of association, and a toner component such as a release agent and a colorant dispersed in the monomer And a method of emulsion polymerization. Here, the association means that a plurality of resin particles and colorant particles are fused.

  That is, various constituent materials such as a colorant and, if necessary, a release agent, a charge control agent, and a polymerization initiator are added to the polymerizable monomer, and a homogenizer, a sand mill, a sand grinder, an ultrasonic disperser, etc. Various constituent materials are dissolved or dispersed in the polymerizable monomer. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in oil droplets having a desired size as a toner in an aqueous medium containing a dispersion stabilizer using a homomixer or a homogenizer. Thereafter, the stirring mechanism is transferred to a reactor that is a stirring blade described later, and the polymerization reaction is advanced by heating. After completion of the reaction, the dispersion stabilizer is removed, filtered, washed, and dried to prepare a toner.

  Further, as a method for producing the toner of the present invention, a method of preparing by associating or fusing resin particles in an aqueous medium can also be mentioned. The method is not particularly limited, and examples thereof include methods disclosed in JP-A-5-265252, JP-A-6-329947, and JP-A-9-15904. That is, a method of associating a plurality of fine particles composed of resin particles and colorants, etc., or particles composed of resin and colorant, in particular, after dispersing them in water using an emulsifier, the critical aggregation concentration The above flocculant is added for salting out, and at the same time, the formed polymer itself is heated and fused at a temperature higher than the glass transition temperature to gradually grow the particle size while forming fused particles. Then, a large amount of water was added to stop the particle size growth, and the particle surface was smoothed while heating and stirring to control the shape, and the particles were heated and dried in a fluidized state while containing water, whereby a toner was obtained. Can be formed. Here, an organic solvent that is infinitely soluble in water may be added simultaneously with the flocculant.

Note that materials and manufacturing methods for producing a uniform toner such as a shape factor used in the present invention, a polymerization toner reaction device, and the like are described in detail in JP-A-2000-214629.
<Developer>
The toner used in the present invention may be a one-component developer or a two-component developer, but is preferably a two-component developer.

  When used as a one-component developer, there is a method in which the toner is used as it is as a non-magnetic one-component developer. Usually, however, the toner particles contain about 0.1 to 5 μm of magnetic particles as a magnetic one-component developer. Use. As a method for its inclusion, it is usually contained in non-spherical particles in the same manner as the colorant.

  Further, it can be mixed with a carrier and used as a two-component developer. In this case, conventionally known materials such as metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead are used as the magnetic particles of the carrier. Ferrite particles are particularly preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 60 μm.

  The volume average particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene / acrylic resin, silicone resin, ester resin, or fluorine-containing polymer resin is used. The resin for constituting the resin-dispersed carrier is not particularly limited, and known resins can be used. For example, a styrene acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like can be used. it can.

FIG. 1 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention.

  This color image forming apparatus is called a tandem type color image forming apparatus, and includes four sets of image forming units (image forming units) 10Y, 10M, 10C, and 10Bk, an endless belt-shaped intermediate transfer body unit 7, and a feeding unit. It comprises a paper conveying means 21 and a fixing means 24. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  An image forming unit 10Y that forms a yellow image includes a charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, and a primary transfer unit disposed around a drum-shaped photoconductor 1Y as a first image carrier. A primary transfer roller 5Y and a cleaning means 6Y are provided. An image forming unit 10M that forms a magenta image includes a drum-shaped photosensitive member 1M as a first image carrier, a charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roller 5M as a primary transfer unit, It has a cleaning means 6M. An image forming unit 10C for forming a cyan image includes a drum-shaped photoreceptor 1C as a first image carrier, a charging unit 2C, an exposure unit 3C, a developing unit 4C, and a primary transfer roller 5C as a primary transfer unit. It has cleaning means 6C. The image forming unit 10Bk that forms a black image includes a drum-shaped photoreceptor 1Bk as a first image carrier, a charging unit 2Bk, an exposure unit 3Bk, a developing unit 4Bk, a primary transfer roller 5Bk as a primary transfer unit, and a cleaning unit. 6Bk.

  The four sets of image forming units 10Y, 10M, 10C, and 10K include charging means 2Y, 2M, 2C, and 2K that rotate around the photosensitive drums 1Y, 1M, 1C, and 1K, and image exposure means 3Y, 3M, 3C and 3K, rotating developing means 4Y, 4M, 4C and 4K, and cleaning means 5Y, 5M, 5C and 5K for cleaning the photosensitive drums 1Y, 1M, 1C and 1K.

  The image forming units 10Y, 10M, 10C, and 10K have the same configuration except that the colors of the toner images formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are different, and the image forming unit 10Y is taken as an example in detail. explain.

  The image forming unit 10Y has a charging unit 2Y (hereinafter simply referred to as a charging unit 2Y or a charger 2Y), an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 5Y (around a photosensitive drum 1Y as an image forming body). Hereinafter, the cleaning means 5Y or the cleaning blade 5Y) is simply disposed, and a yellow (Y) toner image is formed on the photosensitive drum 1Y. In the present embodiment, in the image forming unit 10Y, at least the photosensitive drum 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 5Y are provided so as to be integrated.

  The charging unit 2Y is a unit that applies a uniform potential to the photosensitive drum 1Y. In the present embodiment, a corona discharge type charger 2Y is used for the photosensitive drum 1Y.

  The image exposure unit 3Y performs exposure based on the image signal (yellow) on the photosensitive drum 1Y given a uniform potential by the charger 2Y to form an electrostatic latent image corresponding to the yellow image. As the exposure means 3Y, the exposure means 3Y includes an LED in which light emitting elements are arranged in an array in the axial direction of the photosensitive drum 1Y and an imaging element (trade name; Selfoc lens), or A laser optical system or the like is used.

In the image forming method of the present invention, when an electrostatic latent image is formed on a photoreceptor, it is preferable to perform image exposure using an exposure beam having a spot area of 2000 μm ² or less. Even when such small-diameter beam exposure is performed, the organic photoreceptor of the present invention can faithfully form an image corresponding to the spot area. A more preferable spot area is 100 to 1000 μm ² . As a result, an electrophotographic image having a gradation of not less than 800 dpi (dpi is the number of dots per 2.54 cm) can be achieved.

The spot area of the exposure beam is a light intensity distribution plane appearing on the cut surface when the exposure beam is cut along a plane perpendicular to the beam, and in a region where the light intensity is 1 / e ² or more of the maximum peak intensity. It means the corresponding area.

Examples of the light beam used include a scanning optical system using a semiconductor laser, and a solid state scanner such as an LED or a liquid crystal shutter. The light intensity distribution includes a Gaussian distribution and a Lorentz distribution, but 1 / e of each peak intensity. ^The area up to ² is the spot area.

  The endless belt-like intermediate transfer body unit 7 includes an endless belt-like intermediate transfer body 70 as a second image carrier having a semiconductive endless belt shape that is wound around a plurality of rollers and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10Bk is sequentially transferred onto a rotating endless belt-shaped intermediate transfer body 70 by primary transfer rollers 5Y, 5M, 5C, and 5Bk as primary transfer means. Thus, a synthesized color image is formed. A sheet P as a recording material (a support for carrying a fixed final image: for example, plain paper, transparent sheet, etc.) housed in the sheet feeding cassette 20 is fed by a sheet feeding means 21 and has a plurality of intermediate rollers. After passing through 22A, 22B, 22C, 22D and the registration roller 23, it is conveyed to a secondary transfer roller 5b as a secondary transfer means, and is secondarily transferred onto the paper P and a color image is collectively transferred. The paper P on which the color image has been transferred is fixed by the fixing unit 24, is sandwiched between the paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus.

  On the other hand, after the color image is transferred onto the paper P by the secondary transfer roller 5b as the secondary transfer means, the residual toner is removed by the cleaning means 6b from the endless belt-shaped intermediate transfer body 70 from which the paper P is separated by curvature.

  During the image forming process, the primary transfer roller 5Bk is always in pressure contact with the photoreceptor 1Bk. The other primary transfer rollers 5Y, 5M, and 5C are in pressure contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5b is in pressure contact with the endless belt-shaped intermediate transfer body 70 only when the sheet P passes through the secondary transfer roller 5b and the secondary transfer is performed.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10Bk and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10Bk are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1Bk in the drawing. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 73, 74, primary transfer rollers 5Y, 5M, 5C, 5Bk, and cleaning means 6b. Consists of.

  Next, FIG. 2 shows a color image forming apparatus using the organic photoreceptor of the present invention (a copying machine having at least a charging means, an exposing means, a plurality of developing means, a transfer means, a cleaning means, and an intermediate transfer body around the organic photoreceptor. 1 is a sectional view of the configuration of a laser beam printer). The belt-shaped intermediate transfer body 70 uses an elastic body having a medium resistance.

  Reference numeral 1 denotes a rotary drum type photoconductor that is repeatedly used as an image forming body, and is rotationally driven in a counterclockwise direction indicated by an arrow at a predetermined peripheral speed.

  During the rotation process, the photosensitive member 1 is uniformly charged to a predetermined polarity and potential by the charging unit 2 and then modulated in accordance with a time-series electric digital pixel signal of image information by an image exposure unit 3 (not shown). An electrostatic latent image corresponding to a yellow (Y) color component image of a target color image is formed by receiving image exposure with scanning exposure light or the like by a laser beam.

  Next, the electrostatic latent image is developed with yellow toner as the first color by yellow (Y) developing means (yellow color developing device) 4Y. At this time, the second to fourth developing means (magenta developer, cyan developer, black developer) 4M, 4C, and 4Bk are turned off and do not act on the photosensitive member 1. The first color yellow toner image is not affected by the second to fourth developing units.

  The intermediate transfer member 70 is stretched by rollers 79a, 79b, 79c, 79d, and 79e, and is driven to rotate in the clockwise direction at the same peripheral speed as the photosensitive member 1.

  The first color yellow toner image formed and supported on the photosensitive member 1 is applied to the intermediate transfer member 70 from the primary transfer roller 5a in the process of passing through the nip portion between the photosensitive member 1 and the intermediate transfer member 70. The intermediate transfer (primary transfer) is sequentially performed on the outer peripheral surface of the intermediate transfer body 70 by the electric field formed by the primary transfer bias.

  The surface of the photoreceptor 1 after the transfer of the first color yellow toner image corresponding to the intermediate transfer body 70 is cleaned by the cleaning device 6a.

  Similarly, the second color magenta toner image, the third color cyan toner image, and the fourth color black (black) toner image are sequentially superimposed and transferred onto the intermediate transfer body 70 to correspond to the target color image. A superimposed color toner image is formed.

  The secondary transfer roller 5b is supported in parallel with the secondary transfer counter roller 79b so as to be separated from the lower surface of the intermediate transfer body 70.

  The primary transfer bias for sequentially superimposing and transferring the first to fourth color toner images from the photosensitive member 1 to the intermediate transfer member 70 has a polarity opposite to that of the toner and is applied from a bias power source. The applied voltage is, for example, in the range of +100 V to +2 kV.

  In the primary transfer process of the first to third color toner images from the photosensitive member 1 to the intermediate transfer member 70, the secondary transfer roller 5b and the intermediate transfer member cleaning means 6b can be separated from the intermediate transfer member 70. is there.

  When the superimposed color toner image transferred onto the belt-shaped intermediate transfer member 70 is transferred to the transfer material P, which is the second image carrier, the secondary transfer roller 5b is brought into contact with the belt of the intermediate transfer member 70. At the same time, the transfer material P is fed from the pair of paper registration rollers 23 through the transfer paper guide to the belt of the intermediate transfer body 70 to the contact nip with the secondary transfer roller 5b at a predetermined timing. A secondary transfer bias is applied to the secondary transfer roller 5b from a bias power source. By this secondary transfer bias, the superimposed color toner image is transferred (secondary transfer) from the intermediate transfer body 70 to the transfer material P as the second image carrier. The transfer material P that has received the transfer of the toner image is introduced into the fixing means 24 and heated and fixed.

  The organophotoreceptor of the present invention is generally applicable to electrophotographic apparatuses such as electrophotographic copying machines, laser printers, LED printers, and liquid crystal shutter printers, but also displays, recordings, light printing, plate making and facsimiles using electrophotographic technology. The present invention can be widely applied to such devices.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. However, “part” in the following text indicates “part by mass”.

  A photoreceptor used for evaluation was produced as follows.

Example 1
A photoreceptor containing the mixed compound of the general formula A was produced as follows.
Preparation of photoreceptor 1A <intermediate layer>
Polyamide resin (Amilan CM-8000: manufactured by Toray Industries, Inc.) 60 parts Inorganic fine particles: Titanium oxide SMT500SAS (manufactured by Teica; surface treatment is silica treatment, alumina treatment, and methylhydrogenpolysiloxane treatment) 180 parts Methanol 1600 parts 1- Butanol 400 parts The above components were mixed and dissolved to prepare an intermediate layer coating solution. This coating solution was applied onto a cylindrical aluminum substrate by a dip coating method, and after drying, an intermediate layer having a thickness of 1.0 μm was formed.
<Charge generation layer>
Titanyl phthalocyanine pigment (pigment with Cu-Kα characteristic X-ray diffraction spectrum, maximum peak of Bragg angle 2θ of 27.3 °) 60 parts Silicone resin solution (KR5240, 15% xylene-butanol solution: Shin-Etsu Chemical Co., Ltd.) 700 parts 2-butanone 2000 parts The above components were mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied onto the intermediate layer by a dip coating method, and after drying, a charge generation layer having a thickness of 0.3 μm was formed.
<Charge transport layer>
Charge transport material (compound of synthesis example (1)) 150 parts Binder resin: Bisphenol Z type polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Company) 300 parts Antioxidant (Sanol LS2626: manufactured by Sankyo Co., Ltd.) 1.7 parts Tetrahydrofuran ( Boiling point: 64.5 ° C.) 2200 parts The above components were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method and dried at 100 ° C. for 40 minutes to form a charge transport layer having a thickness of 22 μm, thereby producing a photoreceptor 1A.

Preparation of photoconductors 2A to 14A Photoconductors 2A to 14A in the same manner as in photoconductor 1A, except that the charge generation material, the compound of the charge transport material, the amount of the compound, and the thickness of the charge transport layer were changed as shown in Table 1. Was made.

Production of Photoreceptor 15A In the production of Photoreceptor 1A, only n = 0 of Compound 21A (p = 0, q = 0) synthesized separately by a known method was used as a charge transport material (the compound of Synthesis Example (1)). Photoreceptor 15A was produced in the same manner except that the charge transporting material (component purity greater than 99%) was used.

Production of Photoreceptor 16A In production of Photoreceptor 1, the charge transport material (the compound of Synthesis Example (1)) was separated from the component of Synthesis Example (1) by liquid chromatography to obtain Compound 21A (p = 0). The photoconductor 16A was prepared in the same manner except that the charge transporting material was replaced by a charge transporting material having only n = 3 (component purity greater than 99%) in q = 0). The charge transporting material was compatible with the binder resin. No photoconductor was obtained that could be evaluated.

Preparation of Photoconductor 17A In Photoconductor 1, the components of the charge transport material (1), the compound of Synthesis Example (1) were separated by liquid chromatography, and the components of Compound 21A (p = 0, q = 0) were separated. A photoconductor 17A was produced in the same manner except that the mixed compound charge transporting material having a composition ratio of n = 1 and n = 2 was 50%.

In the table, Y is a titanyl phthalocyanine pigment (a pigment having a maximum peak at a Bragg angle 2θ of 27.3 ° in a Cu-Kα characteristic X-ray diffraction spectrum).
Z represents a benzimidazole perylene pigment (a pigment having a maximum peak at a Bragg angle 2θ of 12.4 ° in a Cu-Kα characteristic X-ray diffraction spectrum).

  (X + y) represents the sum (in%) of the composition ratio x of the compound of the maximum component of the mixed compound of the present invention and the composition ratio y of the compound of the 2-position component.

  The distribution (composition ratio) of the chain structure n of the charge transport material was determined from the area ratio of high performance liquid chromatography. Average molecular weight Mw shows the weight average molecular weight (polystyrene conversion) calculated | required from the gel permeation chromatography (GPC).

<< Evaluation 1 >>
Evaluation was performed using a digital copying machine having an intermediate transfer member having the structure shown in FIG. (Image quality evaluation in a system (tandem type) in which toner images with different colors are formed on a plurality of photosensitive members and transferred onto an intermediate transfer member to form a color image). As shown in Table 3, the photoconductor and the developer were combined (combinations 1A to 17A) and mounted on a digital copying machine for evaluation.

Process conditions Line speed L / S for image formation: 180 mm / s
Each of the above photoreceptors 1A to 17A was used (4 photoreceptors 1Y, 1M, 1C, and 1Bk).

  Charging condition of the photoconductor (40 mmφ): The potential of the non-image part is detected by a potential sensor, and feedback control is possible. A charge potential of −750 V is applied to each photoconductor, and the photoconductor in the case of full exposure. The surface potential was in the range of −50 to 0V.

Image exposure conditions: semiconductor laser, exposure spot area: 7.5 × 10 ⁻¹⁰ m ² , 800 dpi
Development: Yellow toner, magenta toner, cyan toner, and black toner used in each developing means (4Y, 4M, 4C, 4Br) have a physical property value such as a shape factor shown in Table 2, Group 1, Group 2, Groups of polymerized toner groups were used. The yellow toner, magenta toner, cyan toner and black toner in each group contain an external additive of 0.3 μm hydrophobic titanium oxide and 15 nm hydrophobic silica, respectively. A two-component developer made of a ferrite carrier was used. Reverse development method

Intermediate transfer member: A seamless endless belt-like intermediate transfer member 70, a belt made of a semiconductive resin and having a volume resistivity of 1 × 10 ⁸ Ω · cm and Rz of 0.9 μm was used.

Primary transfer conditions Primary transfer roller (5Y, 5M, 5C, 5Bk (each 6.05 mmφ) in FIG. 1): Configuration in which elastic rubber is attached to the core: Surface specific resistance 1 × 10 ⁶ Ω, transfer voltage applied Secondary transfer Conditions An endless belt-shaped intermediate transfer body 70 as an intermediate transfer body and a backup roller 74 and a secondary transfer roller 5b are arranged so as to sandwich the endless belt-shaped intermediate transfer body 70, and the resistance value of the backup roller 74 is 1 × 10 ⁶ Ω, and the secondary transfer The resistance value of the secondary transfer roller as a means is 1 × 10 ⁶ Ω, and constant current control (about 80 μA) is performed.

  Fixing is a thermal fixing method using a fixing roller in which a heater is disposed inside the roller.

Evaluation Items and Evaluation Criteria Image density Measured using Macbeth RD-918. The relative reflection density was measured with the paper reflection density set to “0”. When the residual potential increases in printing a large number of sheets, the image density decreases. Measurement was performed on solid image portions of each color after printing 10,000 sheets.

A: Each density of a solid (solid) image portion of Bk and Y, M, and C is 1.2 or more (good)
○: Each density of Bk and Y, M, C solid (solid) image part is 0.8 or more (no problem in practical use)
X: The density of at least one of the solid (solid) image portions of Bk and Y, M, and C is less than 0.8 (practical problem)
The fog density was measured by reflection density of a solid white image using RD-918 manufactured by Macbeth. The reflection density was evaluated by a relative density (the density of A4 paper not printed is 0.000). The measurement was performed on the solid white image portion after 10,000 copies each.

A: Concentration is less than 0.010 (good)
○: Concentration of 0.010 or more and 0.020 or less (a level causing no practical problem)
X: Concentration is higher than 0.020 (a level that causes practical problems)
Dash Mark The state of occurrence of a dash mark (small comet-like streak image) whose periodicity coincides with the period of the photoreceptor on the halftone image was determined according to the following criteria.

A: Frequency of dash marks of 0.4 mm or more: All printed images are 5 / A4 or less (good)
O: Frequency of dash marks of 0.4 mm or more: 1 or more of 6 / A4 or more and 10 / A4 or less (no problem in practical use)
X: Frequency of dash mark image defects of 0.4 mm or more: 11 or more A4 or more occurred (practical problem)
Color difference (color shift)
Continuous printing running was performed under an environment of 20 ° C. and 60% RH, and the color of the solid image portion (solid image portion) of the secondary color (red, green, blue) in the image after initial printing and 10,000 printing was “ It was measured by “Macbeth Color-Eye 7000”, and the color difference was calculated using the CMC (2: 1) color difference formula. The secondary color having the largest color difference was selected, and the color difference determined by the CMC (2: 1) color difference formula was 5 or less within the allowable range, and evaluated according to the following criteria.

A: Color difference is less than 3 (good)
○: Color difference of 3 or more and less than 5 (no problem in practical use)
×: Color difference of 5 or more (practical problem)
Sharpness ◎; solid image density is high (density 1.2 or higher), color shift is inconspicuous, and halftone images are reproduced with clean images (good)
○: The density of the solid image is sufficient (density 0.8 or more), the color shift is not noticeable, and the halftone image is reproduced with a clean image (no problem in practical use)
X: The density of the solid image is low (density is less than 0.8), the color shift is conspicuous, or the halftone image is rough. (There are practical problems)
The results are shown in Table 3.

  From Table 3, the tandem type image forming apparatus using the intermediate transfer member has the photoconductor of the present invention, that is, the mixture having the chemical structure of the general formula (1) of the present invention and having a distribution based on n. Assuming that the composition ratio of the compound of the maximum component of the compound is x and the composition ratio of the compound of the 2-position component is y, each of the photosensitive members 1A to 14A using a mixed compound having x + y of 99% or less as a charge transport material The body has a sufficiently high image density, no occurrence of fogging, improved dash marks, small color difference (color shift) after 10,000 printing, and a color image with good sharpness from the initial to 10,000 printing. It has been. On the other hand, the photoconductor 15A using only a low molecular weight compound of n = 0 has a soft charge transport layer, has many dash marks, has a large color difference after 10,000 printing, and deteriorates sharpness. Further, in the case of the photoconductor 16A using only a high molecular weight compound of n = 3, it was poorly dissolved in the binder resin, had almost no sensitivity, and was not worthy of evaluation. In addition, the photoconductor 17A using a compound 21A (p = 0, q = 0) in which the compound ratio of n = 1 and n = 2 is 50% as a charge transporting material also reduces the image density and causes fogging. And the color difference after 10,000 printing is large, and the sharpness is also deteriorated.

<< Evaluation 2 >>
Evaluation was performed using a digital copying machine having an intermediate transfer member having the structure shown in FIG. (Evaluation of image quality by forming a color toner image on a single photoconductor, and then transferring these toner images onto an intermediate transfer body in sequence)
The photoconductors 1A to 17A are combined with a developer in the same manner as in Evaluation 1, and mounted on a commercially available color printer, magiccolor 2300 Desk Laser (manufactured by Minolta EMS), and subjected to a durability test at low temperature and low humidity (LL: 10 ° C., 20% RH). went. Specifically, a total of 10,000 image images with a pixel ratio of 7%, halftone images, solid white images, and solid black images, each of which is divided into quarters, are printed at the start and after printing 10,000 sheets. evaluated. Evaluation items and evaluation criteria are shown below.

  The process conditions for the color printer were as follows.

Charger: Sawtooth electrode Exposure device: Semiconductor laser Development: The yellow toner, magenta toner, cyan toner and black toner used in each developing means (4Y, 4M, 4C, 4Br) are listed in Table 2 used in Evaluation 1. Group 1, 2, 3 polymer toner groups having physical properties such as shape factor were used. However, the external additive 0.3 μm hydrophobic titanium oxide was changed to 0.3 μm strontium titanate (15 nm hydrophobic silica was not changed), and a developer of a non-magnetic polymer toner without using a carrier was used. . The combination of the photoreceptor and the developer (toner group) was combined in the same manner as in Evaluation 1. Reverse development method Transfer: Use of intermediate transfer belt Cleaning: Cleaning blade Fixing: Heat fixing Process speed: 100 mm / sec
The evaluation items and evaluation criteria were the same as those in << Evaluation 1 >>. As a result, the evaluation results of the respective photoreceptors were almost the same as those in << Evaluation 1 >>.

1 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention. 1 is a cross-sectional view of a color image forming apparatus using an organic photoreceptor of the present invention. (A) is explanatory drawing which shows the projection image of a toner particle without an angle | corner, (b) and (c) are explanatory drawings which show the projection image of a toner particle with an angle | corner, respectively.

Explanation of symbols

1Y, 1M, 1C, 1Bk photoconductor 2Y, 2M, 2C, 2Bk charging unit 3Y, 3M, 3C, 3Bk exposure unit 4Y, 4M, 4C, 4Bk developing unit 5b secondary transfer roller (secondary transfer unit)
5Y, 5M, 5C, 5Bk Primary transfer roller (primary transfer means)
6b, 6Y, 6M, 6C, 6Bk Cleaning means 7 Endless belt-shaped intermediate transfer body unit 10Y, 10M, 10C, 10Bk Image forming unit (image forming unit)
61 Blade 62 Bracket 63 Spindle 70 Endless belt-shaped intermediate transfer member

Claims (14)

A plurality of image forming units having at least developing means are provided, and each colored toner image is formed on the organic photoreceptor using toner whose color is changed for each of the plurality of image forming units, and the formed toner images are intermediately formed. A color toner image is formed by sequentially superimposing and transferring on a transfer body, the color toner image is collectively retransferred onto a recording material, and the retransferred color toner image is fixed to form a color image. In the image forming apparatus, the organophotoreceptor has a chemical structure of the following general formula (1), and the composition ratio of the maximum component compound of the mixed compound having a distribution based on n is x, the compound of the 2-position component An image forming apparatus comprising a mixed compound in which x + y is 94.3% or less, where y is a composition ratio.
General formula (1)
X- (CTM group) _n -Y
In the general formula (1), the CTM group, 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. A plurality of image forming units having at least an organic photoconductor, a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit are arranged, and an organic photoconductor using a toner whose color is changed for each of the plurality of image forming units. Each colored toner image formed thereon is sequentially superimposed and transferred onto an intermediate transfer member to form a color toner image, and the color toner image is collectively re-transferred onto a recording material, and the re-transferred color In an image forming apparatus for fixing a toner image to form a color image, the organic photoreceptor has a chemical structure represented by the following general formula (1) and has a distribution based on n and is the largest component compound compound An image forming apparatus comprising a mixed compound in which x + y is 94.3% or less, where x is a composition ratio of a 2-position compound and y is a composition ratio of a compound at the 2-position.
General formula (1)
X- (CTM group) _n -Y
In the general formula (1), the CTM group, 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 image forming apparatus according to claim 1, wherein x + y in the general formula (1) is in the following range.
30% ≦ x + y ≦ 94.3% The image forming apparatus according to claim 1, wherein the divalent group containing the triarylamine group of A is a group of the following general formula (4).

In General Formula (4), Ar ₃ represents a substituted or unsubstituted monovalent aromatic group. The image forming apparatus according to claim 4, wherein the Ar ₃ is a group of the following general formula (5).

In the general formula (5), R ₃₁ , R ₃₂ , R ₃₃ , R ₃₄ and R ₃₅ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. However, at least one of R ₃₁ and R ₃₅ is an alkyl group having 1 to 4 carbon atoms. The image forming apparatus according to claim 1, wherein the divalent group containing the triarylamine group of A is a group of the following general formula (6).

In General Formula (6), X ₂ is a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted divalent aromatic group, and Ar ₄ and Ar ₅ are substituted or unsubstituted monovalent aromatic groups. Indicates. The organic photoreceptor has a layer structure in which a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material are laminated on a conductive support, and the charge transport layer is represented by the general formula (1) X + y is 94.3% or less, where x is the composition ratio of the compound of the largest component of the mixed compound having the chemical structure and distribution based on n, and y is the composition ratio of the compound of the 2-position component. The image forming apparatus according to claim 1, further comprising a compound. The image forming apparatus according to claim 7, wherein the charge transport layer forms a surface layer of an organic photoreceptor. 9. The image forming apparatus according to claim 7, further comprising an intermediate layer between the conductive support and the charge generation layer. A plurality of image forming units having at least developing means are provided, and each colored toner image is formed on the organic photoreceptor using toner whose color is changed for each of the plurality of image forming units, and the formed toner images are intermediately formed. A color toner image is formed by sequentially superimposing and transferring on a transfer body, the color toner image is collectively retransferred onto a recording material, and the retransferred color toner image is fixed to form a color image. In the image forming apparatus, the organophotoreceptor has a chemical structure of the following general formula (1), and the composition ratio of the maximum component compound of the mixed compound having a distribution based on n is x, the compound of the 2-position component Where the composition ratio of y is a toner that contains a mixed compound having x + y of 94.3% or less, and the developing means has 65% or more of toner particles having a shape factor in the range of 1.2 to 1.6. It is characterized by containing Image forming apparatus.
General formula (1)
X- (CTM group) _n -Y
In the general formula (1), the CTM group, 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. A plurality of image forming units having at least developing means are provided, and each colored toner image is formed on the organic photoreceptor using toner whose color is changed for each of the plurality of image forming units, and the formed toner images are intermediately formed. A color toner image is formed by sequentially superimposing and transferring on a transfer body, the color toner image is collectively retransferred onto a recording material, and the retransferred color toner image is fixed to form a color image. In the image forming apparatus, the organophotoreceptor has a chemical structure of the following general formula (1), and the composition ratio of the maximum component compound of the mixed compound having a distribution based on n is x, the compound of the 2-position component An image forming apparatus comprising: a mixed compound containing x + y of 99% or less, wherein the developing means contains 50% by number or more of toner particles having no corners.
General formula (1)
X- (CTM group) _n -Y
In the general formula (1), the CTM group, 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. A plurality of image forming units having at least developing means are provided, and each colored toner image is formed on the organic photoreceptor using toner whose color is changed for each of the plurality of image forming units, and the formed toner images are intermediately formed. A color toner image is formed by sequentially superimposing and transferring on a transfer body, the color toner image is collectively retransferred onto a recording material, and the retransferred color toner image is fixed to form a color image. In the image forming apparatus, the organophotoreceptor has a chemical structure of the following general formula (1), and the composition ratio of the maximum component compound of the mixed compound having a distribution based on n is x, the compound of the 2-position component Where x + y is 94.3% or less of the mixed compound, and the developing means takes the natural logarithm lnD on the horizontal axis when the toner particle diameter is D (μm). Multiple horizontal axes at intervals of 0.23 A relative frequency of toner particles included in the most frequent class in the histogram showing a particle size distribution of number-based divided into classes (m _1), the relative frequency of the toner particles contained in the following frequent the rank of the modal class ( An image forming apparatus comprising a toner having a sum (M) of m ₂ ) of 70% or more.
General formula (1)
X- (CTM group) _n -Y
In the general formula (1), the CTM group, 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. A plurality of image forming units having at least developing means are provided, and each colored toner image is formed on the organic photoreceptor using toner whose color is changed for each of the plurality of image forming units, and the formed toner images are intermediately formed. A color toner image is formed by sequentially superimposing and transferring on a transfer body, the color toner image is collectively retransferred onto a recording material, and the retransferred color toner image is fixed to form a color image. In the image forming apparatus, the organophotoreceptor has a chemical structure of the following general formula (1), and the composition ratio of the maximum component compound of the mixed compound having a distribution based on n is x, the compound of the 2-position component Is a mixed compound having x + y of 94.3% or less, and the developing means has a variation coefficient of the shape factor of toner particles of 16% or less and a number variation coefficient of 27% in the number particle size distribution. The following An image forming apparatus characterized by containing over.
General formula (1)
X- (CTM group) _n -Y
In the general formula (1), the CTM group, 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 image forming method comprising forming an electrophotographic image using at least the image forming apparatus according to claim 1.

Images