JP2005134515A - Electrophotographic photoreceptor, process cartridge, image forming apparatus and method for forming image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which can prevent dielectric breakdown or an image defect such as a black spot that is apt to occur during repeated use of an electrophotographic photoreceptor used for a contact charging type image forming process, and which can stably form an image with favorable sharpness for a long time, and to provide a process cartridge using the electrophotographic photoreceptor, an image forming apparatus and a method for forming an image. <P>SOLUTION: The electrophotographic photoreceptor contains a mixture compound including a compound having a structure expressed by general formula (1): X-(CTM)<SB>n</SB>-Y with the distribution on the basis of n, satisfying x+y≤99%, wherein x and y are composition ratios of compounds as the most dominant component and second dominant component, respectively, and has a charge injection layer. In general formula (1), n ranges 0 to 10 and CTM represents a charge transport group. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photosensitive member, a process cartridge, an image forming apparatus, and an image forming method used for electrophotographic image formation, and more specifically, to electrophotographic image formation used in the field of copying machines and printers. The present invention relates to an electrophotographic photosensitive member, a process cartridge, an image forming apparatus, and an image forming method.

  Organic photoconductors have great advantages such as wide selection of materials, excellent environmental suitability and low production costs compared to inorganic photoconductors such as selenium photoconductors and amorphous silicon photoconductors. In recent years, electrophotographic photoreceptors have become the mainstream in place of inorganic photoreceptors.

  On the other hand, in the image forming method based on the Carlson method, a charged, electrostatic latent image is formed on an electrophotographic photosensitive member, and a toner image is formed. Then, the toner image is transferred to a transfer paper, fixed, and finally processed. An image is formed.

  A corona discharger is the best known charging member that has been used as a member of the charging means. The corona discharger has an advantage that stable charging can be performed. However, since a high voltage must be applied to the corona discharger, a large amount of ionized oxygen, ozone, moisture, nitric oxide compound, etc. is generated, which causes deterioration of the organic photoreceptor (hereinafter also referred to as a photoreceptor). Or have problems such as adversely affecting the human body.

  Therefore, in recent years, use of a contact charging method that does not use a corona discharger has been studied. Specifically, a voltage is applied to a magnetic brush or a conductive roller that is a charging member to bring it into contact with a photosensitive member that is a member to be charged, and the surface of the photosensitive member is charged to a predetermined potential. If such a contact charging method is used, the voltage can be lowered and the amount of ozone generated can be reduced as compared with a non-contact charging method using a corona discharger.

In the contact charging method, a direct current voltage or a direct current on which alternating current is superimposed is applied to a charging member having a resistance of about 10 ² to 10 ¹⁰ Ω · cm on the photoconductor, and the photoconductor is pressed and brought into contact with the photoconductor to give an electric charge. Is the method. Since this charging method is performed by discharging from the charging member to the member to be charged in accordance with Paschen's law, charging is started by applying a voltage equal to or higher than a certain threshold value. In this contact charging method, compared with the corona charging method, the voltage applied to the charging member is low, but since discharge is accompanied, a small amount of ozone and nitrogen oxides are generated.

  For this reason, as a new charging method, a charging method by directly injecting charges into the photosensitive member is disclosed (Patent Document 1). This charging method is a method in which a charge injection layer is provided on the surface of a photoconductor, a voltage is applied to a contact conductive member such as a charging roller, a charging brush, a charging magnetic brush, etc., and injection charging is performed by contacting the charge. In this charging method, almost one-to-one charging is possible with respect to the applied voltage with almost no discharge phenomenon. Therefore, compared with the conventional contact charging method, the amount of ozone and NOx generated is very small. It is an excellent charging method with low power.

  As the injection charging method, an electrophotographic photosensitive member having a structure in which a charge injection layer is provided on the surface layer (mostly on a charge transport layer) of the electrophotographic photosensitive member for injection charging is known. That is, an electrophotographic photosensitive member has been proposed in which a charge injection layer containing a binder resin and conductive fine particles or a charge transport material is used as a surface layer (Patent Document 2). However, when the surface of the electrophotographic photosensitive member is repeatedly charged through the charge injection layer by direct contact with a charging roller or the like, cracks, contamination, or the like generated in the charge injection layer occurs. Charges are concentrated in such areas as causing breakdowns and image defects such as black spots and image blurring. In particular, these problems are likely to occur under severe conditions such as high temperature and high humidity and low temperature and low humidity.

  Furthermore, an electrophotographic photosensitive member provided with a charge injection layer is prone to deterioration of electrophotographic characteristics (chargeability and sensitivity) such as a rise in residual potential due to repeated fatigue. In order to improve the electrophotographic characteristics, It has been proposed to contain a charge transport material (Patent Document 3).

However, improvement of the charge injection layer alone is still not sufficient to prevent contact blurring of image blur, electrophotographic characteristics, or prevention of image defects such as dielectric breakdown and black spots, especially at high temperature and high humidity and low temperature. These problems are likely to occur under low humidity conditions.
Japanese Patent Laid-Open No. 6-3921 JP 2002-31911 A JP 2001-194816 A

  The present invention uses an electrification method that generates less ozone and nitrogen oxides and has low power, and further has low dependence on temperature and humidity environment, and can perform long-term stable image formation. And a process cartridge and an image forming apparatus.

  Another object of the present invention is to prevent deterioration of electrophotographic characteristics (sensitivity, residual potential, etc.) that are likely to occur during repeated use in an electrophotographic photoreceptor used in contact charging type image forming methods, An object of the present invention is to provide an electrophotographic photosensitive member, a process cartridge, and an image forming apparatus that can prevent image defects such as black spots from occurring and can perform stable long-term image formation with good sharpness.

  As a result of intensive studies, the present inventors have found that the electrophotographic photosensitive member having a charge injection layer includes a conductive support, an intermediate layer, a photosensitive layer, and a charge injection layer. As a result of detailed investigation, the inclusion of a specific charge transport material in the photosensitive layer in contact with the charge injection layer prevents the occurrence of image defects such as dielectric breakdown and black spots and the occurrence of image blur, and repeats Deterioration of electrophotographic characteristics (sensitivity, residual potential, etc.) that are likely to occur during use can be prevented, and an electrophotographic photosensitive member having stable performance over the long term can be provided. The inventors have found that a clear electrophotographic image having a high density and a high resolving power can be stably obtained, thereby completing the present invention.

The object of the present invention is achieved by adopting one of the following configurations.
(Claim 1)
When a compound having the structure of the following general formula (1) and having a distribution based on n is used, the composition ratio of the maximum component of the compound is x, and the composition ratio of the component at the 2nd position is y, x + y is An electrophotographic photoreceptor comprising 99% or less of a mixed compound and having a charge injection layer.

General formula (1) X- (CTM group) _n -Y n = 0 to 10
In general formula (1), the CTM group is a charge transporting group.

X and Y are a hydrogen atom, a halogen atom, or a monovalent organic group n is 0 to 10 (provided that when both X and Y are a hydrogen atom and a halogen atom, n is 1 to 10)
(Claim 2)
In the electrophotographic photosensitive member in which a charge generation layer having a charge generation material, a charge transport layer having a charge transport layer, and a charge injection layer are laminated on a conductive support, the charge transport layer has the structure of the above general formula (1). And a compound having a distribution based on n, wherein x is the maximum component composition ratio and x is the second component composition ratio, and x + y is 99% or less. An electrophotographic photosensitive member characterized by comprising:
(Claim 3)
The electrophotographic photosensitive member according to claim 1, wherein x + y in the general formula (1) is in the following range.

30% ≦ x + y ≦ 99%
(Claim 4)
The electrophotographic photosensitive member according to claim 1, wherein the mixed compound has a weight average molecular weight of 650 to 2500.
(Claim 5)
The electrophotographic photosensitive member according to claim 4, wherein the mixed compound has a weight average molecular weight of 800 to 2,000.
(Claim 6)
6. The electrophotographic photosensitive member according to claim 3, wherein x + y is in the following range.

45% ≦ x + y ≦ 90%
(Claim 7)
The electrophotographic photosensitive member according to claim 1, wherein the CTM group of the general formula (1), X, and Y have the following general formula A.

In the above 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 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 bonded to each other. Also good.

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 8)
The electrophotographic photosensitive member according to claim 1, wherein the CTM group, X, and Y of the general formula (1) has the following general formula B.

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), and R _{1 to} R ₃ represent a hydrogen atom or a substituted atom. , 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 0 or 1 respectively.
(Claim 9)
The electrophotographic photosensitive member according to claim 7 or 8, wherein the divalent group containing the triarylamine group of A is a group of the following general formula (4).

In the general formula (4), Ar ₃ represents a substituted or unsubstituted monovalent aromatic group.
(Claim 10)
The electrophotographic photosensitive member according to claim 9, wherein Ar ₃ is a group of the following general formula (5).

In 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 11)
9. The electrophotographic photosensitive member according to claim 7, 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.
(Claim 12)
The electrophotographic photosensitive member according to claim 8, wherein B is a group represented by the following general formula (7).

In General Formula (7), R ₄₁ , R ₄₂ , R ₄₃ , R ₄₄ , R ₄₅ , R ₅₁ , R ₅₂ , R ₅₃ , R ₅₄ , and R ₅₅ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. . However, at least one of R ₄₁ , R ₄₅ , R ₅₁ and R ₅₅ is an alkyl group having 1 to 4 carbon atoms.
(Claim 13)
The electrophotographic photosensitive member according to any one of claims 1 to 6, wherein the CTM group, X and Y in the general formula (1) has the following general formula C.

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

In General Formula (8), Y is 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.
(Claim 14)
The electrophotographic photosensitive member according to claim 1, wherein the charge injection layer contains conductive particles.
(Claim 15)
When the compound having the structure of the general formula (1) and having a distribution based on n is used, the composition ratio of the maximum component of the compound is x, and the composition ratio of the component at the 2-position is y, x + y is An electrophotographic photosensitive member containing 99% or less of a mixed compound and having a charge injection layer, charging means for uniformly charging the electrophotographic photosensitive member in contact with the electrophotographic photosensitive member, and a charged electrophotographic photosensitive member A latent image forming means for forming an electrostatic latent image on the electrophotographic photosensitive member, a developing means for visualizing the electrostatic latent image on the electrophotographic photosensitive member, and a toner image visualized on the electrophotographic photosensitive member on a transfer material. And at least one of a transfer means for transferring the toner, a charge eliminating means for removing charges on the electrophotographic photosensitive member after the transfer, and a cleaning means for removing residual toner on the electrophotographic photosensitive member after the transfer. And can be detachably attached to the image forming apparatus main body. The process cartridge according to claim.
(Claim 16)
A charging means for uniformly charging the electrophotographic photosensitive member in contact with the electrophotographic photosensitive member, a latent image forming means for forming an electrostatic latent image on the charged electrophotographic photosensitive member, and a static on the electrophotographic photosensitive member. In an image forming apparatus comprising developing means for developing an electrostatic latent image and transfer means for transferring a toner image visualized on the electrophotographic photosensitive member onto a transfer material, the electrophotographic photosensitive member is represented by the general formula When the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of (1) and having a distribution based on n is x, and the composition ratio of the compound of the 2-position component is y, x + y is 99% or less. An image forming apparatus comprising a mixed compound and having a charge injection layer.
(Claim 17)
An image forming method comprising forming an electrophotographic image using the image forming apparatus according to claim 16.

  By using the electrophotographic photosensitive member, the process cartridge and the image forming apparatus of the present invention, it is possible to prevent a rise in residual potential and a change in the charged potential at low temperature and low humidity and high temperature and high humidity, which are likely to occur in the injection charging method, and dielectric breakdown. And image defects can be prevented, and an electrophotographic image with good image density, fog, and sharpness can be provided.

  Hereinafter, the present invention will be described in detail.

  The electrophotographic photoreceptor of the present invention has a compound having a structure represented by the following general formula (1) and a distribution based on n, and the composition ratio of the maximum component of the compound is x and the composition of the 2-position component. When the ratio is y, x + y contains a mixed compound of 99% or less and has a charge injection layer.

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 represents an integer of 0 to 10 (provided that both X and Y are hydrogen atoms or halogen atoms, n is an integer of 1 to 10).

  The electrophotographic photoreceptor used in the present invention is the electrophotographic photoreceptor in which a charge generation layer having a charge generation material, a charge transport layer having a charge transport layer, and a charge injection layer are laminated on a conductive support. The charge transport layer has a compound having the structure of the above general formula (1) and a distribution based on n, the composition ratio of the maximum component of the compound is x, and the composition ratio of the 2-position component is y Then, x + y contains 99% or less of a mixed compound.

  The electrophotographic photosensitive member of the present invention prevents the occurrence of image defects such as dielectric breakdown and black spots that are likely to occur when charging is performed by bringing a charging member into contact with the electrophotographic photosensitive member by having the above-described configuration. In addition, deterioration of electrophotographic characteristics (sensitivity, residual potential, etc.) can be prevented, and long-term stable image formation can be performed.

  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, it means that x + y is 99% or less, and 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 threshold of the discharge breakdown voltage of the electrophotographic photosensitive member having the charge injection layer is remarkably improved, and the occurrence of image defects such as dielectric breakdown and black spots is remarkably suppressed. In addition, deterioration of electrophotographic characteristics (sensitivity, residual potential, etc.) can be prevented, and stable image formation can be performed in the long term.

  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.

  Assuming that 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 is 99. As specific examples of the mixed compound of not more than%, various chemical structures can be considered. 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 (charge transport materials). ), Mixed compounds of general formula A, general formula B, and general formula C described below are exemplified.

  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 bonded to each other. Also good.

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 , R ₂ , 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 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. 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.

  In the structure of the general formula (1) of the present invention, it has a compound having a distribution based on n, 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 Then, although x + y contains a mixed compound of 99% or less, the x + y is preferably 30% to 99%, and 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. Electrophotographic characteristics such as sensitivity and uniform chargeability are remarkably lowered, and dielectric breakdown and black spots are likely to occur. On the other hand, if it is less than 650, the residual potential at low temperature and low humidity tends to increase, and dielectric breakdown and black spots tend to occur at high temperature and high humidity.

Charge Injection Layer The electrophotographic photoreceptor of the present invention has a configuration in which a charge injection layer is provided on a charge transport layer. The charge injection layer is basically composed of a binder resin layer in which conductive fine particles are dispersed.

  As the binder resin for the charge injection layer, the same resin as the charge transport layer described above is used.

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

  The charge injection layer of the present invention preferably contains a charge transport material. By including a charge transport material in the charge injection layer, a decrease in sensitivity and an increase in residual potential due to repeated use can be prevented. The charge injection layer preferably contains a compound having the above-described antioxidant function.

  The thickness of the charge injection layer is suitably from 0.3 to 10 μm, preferably from 1 to 5 μm.

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

  Further, the charge injection layer contains fluorine resin particles, and the contact angle of the photoreceptor surface with water is preferably 90 ° or more, and more preferably 95 ° or more. That is, by increasing the contact angle and reducing the surface energy of the photoreceptor, it is possible to prevent filming due to toner or paper dust on the surface of the photoreceptor, which causes dielectric breakdown and image defects. The fluorine-based resin particles mean resin particles containing fluorine atoms. For example, tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoroethylenepropylene resin, vinyl fluoride resin, vinylidene fluoride resin, It is preferable to appropriately select one or two or more of ethylene difluoride dichloride resin and copolymers thereof, and particularly, tetrafluoroethylene resin and vinylidene fluoride resin are preferable. The molecular weight of the fluororesin particles and the particle diameter of the particles can be appropriately selected and are not particularly limited, but those having a volume average particle diameter of 0.05 to 5 μm are preferable.

  The volume average particle diameter of the fluororesin particles is measured by a laser diffraction / scattering particle size distribution measuring apparatus “LA-700” (manufactured by Horiba, Ltd.). The surface contact angle of the photosensitive member is measured by using a contact angle meter (CA-DT-A type: manufactured by Kyowa Interface Science Co., Ltd.) in an environment of 20 ° C. and 50% RH.

  The composition ratio of the largest component of the mixed compound having such a charge injection layer, having the chemical structure of the general formula (1), and having a distribution based on n is x, the compound of the 2-position component In the electrophotographic photosensitive member containing a mixed compound with x + y of 99% or less as a charge transport material, the threshold value of the discharge breakdown voltage is remarkably improved, and image defects such as dielectric breakdown and black spots are caused. Generation can be remarkably suppressed and deterioration of electrophotographic characteristics (sensitivity, residual potential, etc.) can be prevented, and stable image formation can be performed in the long term.

  As described above, if 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 The charge transport layer containing 99% or less of the mixed compound and the charge injection layer have been described. The layer structure of the electrophotographic photoreceptor other than these, particularly the layer structure of the organic photoreceptor, will be described below.

  In the present invention, the organic photoconductor means an electrophotographic photoconductor formed by providing an organic compound with at least one of a charge generation function and a charge transport function essential to the configuration of the electrophotographic photoconductor. All known organic electrophotographic photoreceptors such as a photoreceptor composed of the above organic charge generating substance or organic charge transporting substance, a photoreceptor composed of a polymer complex with charge generating function and charge transporting function are contained.

  The constitution of the organic photoreceptor preferably 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 depositing alumina, silica, or zirconia on the surface of the N-type semiconducting fine particles. Alumina, silica, and zirconia deposited on these surfaces include alumina, silica, 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), the composition ratio of the compound of the largest component of the mixed compound having the chemical structure of the general formula (1) and having a distribution based on n is x, and the composition of the compound of the second component When the ratio is y, a mixed compound having x + y of 99% or less is used. In addition, 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 the mixed compound. 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 the above-described 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.

  The charge transport layer may be composed of two or more layers. The thickness of the charge transport layer is preferably 10 to 40 μm.

Charge Injection Layer An electrophotographic photoreceptor having the above-described charge injection layer as a surface layer is most preferable.

  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 charge injection 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, tetra Chloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosol Etc. The. 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 charge injection layer. The circular amount regulation type coating is described in detail in, for example, Japanese Patent Application Laid-Open No. 58-189061.

  Next, an image forming apparatus using the contact charging method of the present invention will be described.

<Charging means>
In the present invention, charging is performed by bringing a charging member into contact with the photoreceptor (hereinafter also referred to as charging means using the contact charging member). As such a charging member, various charging members such as a magnetic brush method, a charging roller method, and a blade method can be used. Among these, a charging roller method or a magnetic brush method is most preferable as the charging member and used in the present invention. It is done. That is, a charging roller or a magnetic brush that is easy to obtain charging uniformity is preferable. The charging roller type and magnetic brush type charging means will be described below.

  In the present invention, a charging roller composed of a conductive elastic member can be brought into contact with a photosensitive member (image carrier), and a voltage can be applied to the charging roller to charge the photosensitive member (image carrier).

  Such a charging roller system may be either a DC charging system in which a DC voltage is applied to the roller or an induction charging system in which an AC voltage is applied to the roller.

  In addition, the frequency f of the voltage applied by the induction charging method is arbitrary, but an appropriate frequency is selected according to the relative speed of the conductive elastic roller and the image carrier member in order to prevent strobing, that is, a stripe pattern. Can be selected. The relative speed can be determined by the size of the contact area between the conductive elastic roller and the image carrier.

  The conductive elastic roller is formed by coating the outer periphery of a metal core with a layer made of a conductive elastic member (also simply referred to as a conductive elastic layer or H or a conductive rubber layer).

  Examples of the rubber composition that can be used for the conductive rubber layer include polynorbornene rubber, ethylene-propylene rubber, chloroprene rubber, acrylonitrile rubber, and silicone rubber. These rubber | gum can be used individually or as 2 or more types of mixed rubbers.

  In order to impart conductivity, a conductivity imparting agent is blended with these rubber compositions. Examples of suitable conductivity imparting agents include known carbon black (furnace carbon black or ketien black), metal powder such as tin oxide. The usage-amount of an electroconductivity imparting agent is about 5 to about 50 mass parts with respect to the rubber composition whole quantity.

In addition to the rubber base material, the foaming agent, and the conductivity imparting agent, the rubber composition may be blended with a rubber chemical and a rubber additive as necessary to obtain a conductive foamed rubber composition. Rubber chemicals and rubber additives include vulcanizing agents such as sulfur and peroxide, vulcanization accelerators such as zinc white and stearic acid, vulcanized sulfenamide, thyrium, thiazole and granidine Accelerators, amine-based, phenol-based, sulfur-based, phosphorus-based anti-aging agents, antioxidants, UV absorbers, ozone degradation inhibitors, tackifiers, etc. can be used, and various reinforcing agents In addition, an inorganic filler such as a friction coefficient modifier, silica, talc, clay and the like can be arbitrarily selected and used. These conductive rubber layers preferably have a DC volume resistivity in the range of 10 ³ to 10 ⁷ Ωcm.

Further, on the outside of these conductive elastic layers, a releasable coating layer may be provided for the purpose of preventing the toner remaining on the surface of the photoreceptor from adhering to the charging member. The coating layer also prevents oil seepage from the elastic layer and cancels the resistance unevenness of the elastic layer, uniforms the resistance, protects the surface of the charging roller, and adjusts the hardness of the charging roller. Etc. The covering layer may be any layer as long as it satisfies the above physical properties, and may be a single layer or a plurality of layers. Examples of the material include resins such as hydrin rubber, urethane rubber, nylon, polyvinylidene fluoride, and polyvinylidene chloride. The thickness of the coating layer is preferably 100 to 1000 μm, and the resistance value is preferably 10 ⁵ to 10 ⁹ Ω · cm. Moreover, it is preferable that resistance value becomes large as it approaches the surface layer. Examples of the method for adjusting the resistance include adding a conductive material such as carbon black, metal, and metal oxide to the coating layer.

  In order to adjust the surface roughness Rz of the charging roller, it is preferable to include powder in the surface layer (conductive elastic layer or coating layer) of the charging roller. The granular material used in the present invention may be either an inorganic substance or an organic substance, but in the case of an inorganic substance, silica powder is particularly preferable. In the case of organic substances, for example, urethane resin particles, nylon particles, silicone rubber particles, epoxy resin particles and the like can be mentioned. These particles are used alone or in combination of two or more. A suitable particle may be selected from a material that can adjust the surface roughness Rz of the surface layer to a range of 0.05 to 10.0 μm, but if the particle diameter of the particle is in the range of 1 to 20 μm, the desired surface roughness is selected. The degree range is easy to achieve. If the particle diameter exceeds 20 μm, the surface roughness Rz also exceeds 10.0 μm, which does not fulfill the intended purpose. Conversely, if the particle size is less than 1 μm, the surface roughness Rz tends to be less than 0.05 μm, which also does not fulfill the intended purpose.

  The reason why the surface roughness Rz is set in the range of 0.05 to 10.0 μm is that if it exceeds 10.0 μm, filming of the toner on the roller surface becomes remarkable, and if it is less than 0.05 μm, the charging roller This is because the adhesion between the photosensitive drum and the photosensitive drum is increased, that is, the contact area is increased, so that charging noise cannot be suppressed.

  It is preferable to mix and disperse | distribute the mixture ratio in the surface layer of a powder in the ratio of about 5 to about 20 mass parts with respect to 100 mass parts of resin.

  The charging roller can be manufactured as follows, for example. That is, first, a metal rotating shaft (core metal) is placed in a forming die having a cylindrical forming space, a conductive elastic layer forming material is filled in the forming die, and vulcanization is performed, whereby the outer periphery of the rotating shaft is filled. A conductive elastic layer is formed on the surface. Next, the rotating shaft on which the conductive elastic layer is formed is taken out from the mold. On the other hand, a material such as a urethane resin and granules, a conductivity-imparting agent and other additives are blended, and this blend is mixed and stirred using a ball mill or the like to prepare a surface layer forming material mixture. Then, the mixture is applied to the surface of the rotating shaft on which the conductive elastic layer is formed by a dip method, a roll coating method, a spray coating method, etc., dried to a uniform thickness, and heat-cured to form a two-layer structure. A charging roller can be manufactured. The charging roller thus obtained is formed so that the surface roughness Rz of the outermost surface layer is 0.05 to 10.0 μm.

  Next, the image forming apparatus of the present invention will be described.

  FIG. 1 is a diagram showing an example of an image forming apparatus using charging roller charging. This image forming apparatus is for carrying out the present invention. As a charging means for forming an electrostatic latent image, a charging roller is brought into contact with a photosensitive drum for charging (charging process), and toner is transferred to a transfer paper. A transfer roller is used as a transfer pole (transfer means) for transferring to (transfer process). The transfer roller is in contact with the photosensitive drum directly or with the transfer paper interposed therebetween to avoid the generation of ozone. The so-called contact charging method is adopted, and the electrostatic latent image is formed by non-contact development. Develop.

  In FIG. 1A, an electrostatic latent image is formed on a photosensitive drum 2 charged by a charging roller 1 by image exposure using a laser (image exposure process). The electrostatic latent image is developed into a toner image by a developing sleeve 4 which is a developer carrying member of a developing device (developing means) 3 disposed in the vicinity of the photosensitive drum 2 (developing step). Then, after the charge of the photosensitive drum 2 is discharged by the discharging lamp 5 before transfer, the toner image is transferred to the transfer paper P transported by the transporting roller 8 from the paper feed cassette and transferred to the transfer paper 6 by the reverse polarity of the toner. The toner is transferred onto the transfer paper P by the electrostatic force of the reverse polarity charge. After the toner transfer, the transfer paper P is separated from the photosensitive drum 2 and then sent to the fixing device by the conveying belt 7, and the toner image is fixed to the transfer paper P by the heating roller and the pressing roller (fixing step).

  A bias voltage composed of DC and AC components is applied to the charging roller 1 (and transfer roller 6) from a power source 9 (10), and the charging of the photosensitive drum 2 and the toner image are generated in a state where the amount of ozone generation is extremely small. The transfer paper P is charged. The voltage is preferably a DC bias of ± 300 to 1000 V and an AC bias of 100 to 10 KHz and 200 to 3500 V (pp) superimposed on the DC bias.

  The charging roller 1 and the transfer roller 6 are driven or forcibly rotated under pressure contact with the photosensitive drum 2.

  The pressure contact with the photosensitive drum 2 is 10 to 100 g / cm, and the rotation of the roller is 1 to 8 times the peripheral speed of the photosensitive drum 2.

  As shown in FIG. 1B, the charging roller 1 (and the transfer roller 6) includes a cored bar 20 and a rubber layer such as chlorprene rubber, urethane rubber, and silicone rubber that are conductive elastic members provided on the outer periphery thereof. Or it consists of those sponge layers 21, Preferably it is comprised by providing the protective layer 22 which consists of a mold release fluorine-type resin or silicone resin layer of 0.01-1 micrometer thickness in the outermost layer.

  After the transfer, the photosensitive drum 2 is cleaned by the pressure contact of the cleaning blade 12 of the cleaning device (cleaning means) 11 and used for the next image formation.

  As an electrophotographic image forming apparatus, a photosensitive member and components such as a charging unit, a developing unit, and a cleaning unit are integrally combined as a process cartridge, and this unit is configured to be detachable from the apparatus main body. You may do it. Further, at least one of the image exposure means, the developing means, the transfer or separator, and the cleaning means is integrally supported together with the photosensitive member to form a process cartridge, and is a single unit that is detachable from the main body of the image forming apparatus. It is good also as a structure which can be attached or detached using guide means, such as a rail.

  In FIG. 1, a roller charger is used for both the charger and the transfer electrode. However, in the present invention, the present invention is to use a contact charging member (charging roller or the like) for the charger. Transfer means other than the transfer roller may be used for the poles.

  Next, a magnetic brush charging device using a magnetic brush as the charging member will be described.

  FIG. 2 is a diagram of a contact-type magnetic brush charging device, and FIG. 3 is a diagram showing a relationship between an AC bias voltage and a charging potential by the charging device of FIG.

  In general, if the volume average particle size of the magnetic particles forming the charging magnetic brush is large, the ears of the magnetic brush formed on the charging magnetic particle carrier (conveyance carrier) are rough. However, even when charged, unevenness is likely to appear on the magnetic brush, resulting in a problem of uneven charging. In order to solve this problem, the volume average particle diameter of the magnetic particles may be reduced. As a result of the experiment, the effect starts to appear when the volume average particle diameter is 200 μm or less. The problems associated with the coarseness of the ears are eliminated. However, if the particles are too fine, they will adhere to the surface of the photosensitive drum 50 during charging, or may be easily scattered. These phenomena relate to the strength of the magnetic field acting on the particles and the magnetization strength of the particles, but generally, the volume average particle diameter of the particles becomes noticeable at 20 μm or less.

  From the above, the magnetic particles have a volume average particle size of 200 μm or less, 20 μm or more, and 30% by number or less of magnetic particles having a particle size of 1/2 or less of the number average particle size of the magnetic particles. It is necessary to. The magnetization strength is preferably 30 to 100 emu / g.

  Such magnetic particles are the same as the magnetic carrier particles of the conventional two-component developer described above as the magnetic material, such as metals such as iron, chromium, nickel and cobalt, or their compounds and alloys, such as iron tetroxide. , Γ-ferric oxide, chromium dioxide, manganese oxide, ferrite, manganese-copper alloys, ferromagnetic particles, or the surfaces of these magnetic particles are made of styrene resin, vinyl resin, ethylene resin Particles obtained by coating with a resin such as rosin-modified resin, acrylic resin, polyamide resin, epoxy resin, polyester resin, or made of resin containing dispersed magnetic fine particles are conventionally known. It can be obtained by selecting the particle size with an average particle size selecting means.

  In addition, forming the magnetic particles in a spherical shape has an effect that the particle layer formed on the carrier is uniform, and a high bias voltage can be uniformly applied to the carrier. That is, the magnetic particles are spherical. (1) Generally, magnetic particles are easily magnetized and adsorbed in the long axis direction, but the directionality is lost by the spherical shape, and therefore the magnetic particle layer is formed uniformly. (2) With the increase in resistance of magnetic particles, the edge portion as found in conventional particles is eliminated, and the electric field to the edge portion is prevented. Concentration does not occur, and as a result, even when a high bias voltage is applied to the carrier for charging magnetic particles, the surface of the photosensitive drum 50 is uniformly discharged and charging unevenness does not occur.

Spherical particles having the above effects are preferably those in which conductive magnetic particles are formed so that the resistivity of the magnetic particles is 10 ⁵ to 10 ¹⁰ Ωcm. The resistivity after tapping putting particles in a container having a sectional area of 0.50 cm ^2, a load of 1 kg / cm ² on packed particles, 1000V / cm between the load and a bottom electrode This value is obtained by reading the current value when a voltage generating an electric field is applied. If this resistivity is low, when a bias voltage is applied to the carrier, charges are injected into the magnetic particles, and the Magnetic particles are likely to adhere to the surface of the body drum 50, or dielectric breakdown of the photosensitive drum 50 due to a bias voltage is likely to occur. If the resistivity is high, charge injection is not performed and charging is not performed.

  Furthermore, the magnetic particles used in the contact-type magnetic brush charging device 120 have a small specific gravity and an appropriate maximum magnetization so that the magnetic brush formed by the magnetic brush is moved easily by an oscillating electric field and no external scattering occurs. It is desirable to have Specifically, it has been found that good results can be obtained when the true specific gravity is 6 or less and the maximum magnetization is 30 to 100 emu / g, particularly 40 to 80 emu / g.

In summary, the magnetic particles are spheroidized so that the ratio of the major axis to the minor axis is 3 times or less, there are no protrusions such as needles and edges, and the resistivity is preferably 10 It is desired to be in the range of ⁵ to 10 ¹⁰ Ωcm. For such spherical magnetic particles, select spherical particles as much as possible for magnetic particles, and for magnetic particles dispersed particles, use magnetic particles as much as possible, and perform spheronization after forming dispersed resin particles. Or by forming dispersed resin particles by a spray drying method.

  According to FIG. 2 or FIG. 3, the magnetic brush charging device 120 as a charging device faces the rotating photoconductor drum 50 and is in the same direction (counterclockwise) at a proximity portion (charging unit T) with the photoconductor drum 50. A cylindrical charging sleeve 120a using, for example, an aluminum material or a stainless material, and a magnet body 121 made of N and S poles provided inside the charging sleeve 120a, A magnetic brush made of magnetic particles formed on the outer peripheral surface of the charging sleeve 120 a by the magnet body 121 and charging the photosensitive drum 50, and a magnetic brush on the charging sleeve 120 a at the NN magnetic pole portion of the magnet body 121 are scraped. The scraper 123 to be taken and the magnetic particles in the magnetic brush charging device 120 are stirred or supplied to the magnetic brush charging device 120 when the magnetic particles are supplied. And stirring screw 124 to discharge overflowing from the discharge port 125, constituted by the bristles regulating plate 126 of the magnetic brush. The charging sleeve 120a is rotatable with respect to the magnet body 121, and is 0.1 to 1.0 times in the same direction (counterclockwise) as the movement direction of the photosensitive drum 50 at a position facing the photosensitive drum 50. It is preferably rotated at a peripheral speed. As the charging sleeve 120a, a conductive carrier capable of applying a charging bias voltage is used. In particular, the magnet body 121 having a plurality of magnetic poles inside the conductive charging sleeve 120a having a particle layer formed on the surface thereof. Those having a structure provided with are preferably used. In such a carrier, the magnetic particle layer formed on the surface of the conductive charging sleeve 120a moves up and down in a wave shape due to the relative rotation with the magnet body 121. Even if the magnetic particle layer on the surface of the charging sleeve 120a is somewhat uneven in thickness, the influence is sufficiently covered so as not to cause a problem due to the wavy undulations. The surface of the charging sleeve 120a preferably has an average surface roughness of 5.0 to 30 [mu] m for stable and uniform transfer of magnetic particles. If the surface is smooth, the surface cannot be sufficiently transported. Overcurrent flows from the part, and in any case, uneven charging tends to occur. Sand blasting is preferably used to achieve the above surface roughness. Further, the outer diameter of the charging sleeve 120a is preferably 5.0 to 20 mm. This ensures a contact area necessary for charging. If the contact area is larger than necessary, the charging current becomes excessive, and if it is small, charging unevenness is likely to occur. When the diameter is small as described above, magnetic particles are likely to be scattered or adhere to the photosensitive drum 50 due to centrifugal force. Therefore, the linear velocity of the charging sleeve 120a is almost the same as the moving velocity of the photosensitive drum 50, or more It is also preferable that it is slow.

Further, the thickness of the magnetic particle layer formed on the charging sleeve 120a is preferably a thickness that is sufficiently scraped off by the regulating means to form a uniform layer. If there is too much magnetic particles on the surface of the charging sleeve 120a in the charging region, the magnetic particles will not vibrate sufficiently, causing photoconductor wear and charging unevenness and overcurrent easily flowing, and driving torque of the charging sleeve 120a. Has the disadvantage of becoming larger. On the other hand, if the amount of the magnetic particles on the charging sleeve 120a in the charged region of the magnetic particles is too small, an incomplete portion is formed in contact with the photosensitive drum 50, and adhesion of the magnetic particles on the photosensitive drum 50 or uneven charging occurs. become. Result of repeated experimentation, the preferred deposition amount of the magnetic particles in the charging area is 100 to 400 mg / cm ^2, particularly preferably has proven 200-300 mg / cm ^2. This adhesion amount is an average value in the charging region of the magnetic brush.

The magnetic brush charging device 120 serving as a charging device includes a charging bias in which an alternating current (AC) bias AC3 is superimposed on a direct current (DC) bias E3 as necessary, for example, a direct current bias E3 having the same polarity as the toner (in this embodiment, minus). Polarity) of −100 to −500 V, and the charging sleeve 120a to which a charging bias of a frequency of 1 to 5 kHz and a voltage of 300 to 500 V _P - _P is applied as the AC bias AC3, the peripheral surface of the photosensitive drum 50 is brought into contact and sliding. The photosensitive drum 50 is charged by rubbing. Since an oscillating electric field is formed between the charging sleeve 120a and the photosensitive drum 50 by applying the voltage of the AC bias AC3, the electric charge is smoothly injected onto the photosensitive layer 10a through the magnetic brush. High-speed charging is performed uniformly.

  The magnetic brush on the charging sleeve 120a charged with the photosensitive drum 50 is dropped from the charging sleeve 120a by the scraper 123 at the NN magnetic pole portion provided in the magnet body 121, and the charging sleeve 120a in the vicinity of the charging sleeve 120a. Then, the magnetic brush is formed again and conveyed to the charging unit T after being stirred by the stirring screw 124 rotating in the opposite direction (counterclockwise).

As shown in FIG. 3, the relationship between the peak-to-peak voltage (V _{P -P} ) of the AC bias AC3 of the charging bias and the charging potential is such that the charging potential increases as the peak-to-peak voltage V _{P -P} increases. The charging potential is saturated at a constant peak-to-peak voltage V1 and substantially equal to the value VS of the DC bias E3 of the charging bias, and the charging potential hardly changes even if the peak-to-peak voltage V _{P -P} is further increased. There is a characteristic. Although the electric resistance of the magnetic particles varies depending on the environmental conditions, the electric resistance increases as the toner is fused to the surface of the magnetic particles as it is used. For this reason, the characteristic curve is shown on the left side as shown by a solid line in the case of new magnetic particles in the initial stage of use, and the characteristic curve is shown on the right side as shown in FIG. Will be located.

In the charging device using the contact method of the image forming apparatus of the present invention, the voltage value of the DC bias E3 corresponding to the charging potential is set to a predetermined value when the mounted power source is turned on or before printing is started, and the peak-to-peak voltage (V A charging bias with _P - _P ) gradually increased from a low value is applied, and the charging potential of the photosensitive drum 50 that changes at that time is detected by an electrometer ES. The detected charging potential is converted into a digital value by an A / D converter and then input to a control unit (CPU). In the control unit, the value of V _{P -P} when the charged potential reaches the saturation point of the predetermined value VS is defined as an appropriate bias value V1, and the printing operation is performed.

That is, when printing is performed, the AC bias AC3 is gradually increased (swept) from a low value to obtain the value V1 of V _{P -P} of the AC bias AC3, and a bias signal is output from the control unit. This control signal is converted to an analog value by the D / A converter and then sent to the AC bias AC3. The AC bias AC3 outputs the determined peak-to-peak voltage V1. At this time, the value of the peak-to-peak voltage V1 and the specified value V2 to be exchanged due to the deterioration of the magnetic particles stored in the memory are read and compared. Since the resistance of the magnetic particles increases due to toner mixing, the proper bias value V1 increases as the print is used. Along with this, V _{P -P to} be applied increases and an unchargeable state occurs. The image formation is continued while the measured voltage value is smaller than the prescribed value V2 indicating that charging is not possible. However, when the measured voltage value is larger than the prescribed value V2, an image forming operation stop signal is sent from the control unit to stop the image forming operation. The charging unit abnormality is displayed on the display unit of the operation unit. Based on this display, the charging magnetic particle supply bottle 220 is set in the magnetic brush charging device 120, and an opening / closing lid (not shown) on the bottom of the supply bottle 220 is opened to drop and supply the magnetic particles to the magnetic brush charging device 120. To do. In the above description, the electrometer ES is used to measure the potential of the photosensitive drum 50. When the DC bias ammeter is connected to the bias power source and the AC bias V _{P -P} is changed, the current value reaches the saturation point. of V _P - set a proper bias value V1 _P, may be to supply the magnetic particles when exceeded V1 compares the specified value V2.

  In addition, the magnetic particles for charging are exchanged during maintenance or at regular intervals such as 50,000 prints. At each maintenance print stored in the memory or at regular intervals of, for example, 50,000 prints, an exchange signal is output through the control unit, and supply of the charging magnetic particle supply bottle 220 set in advance by driving a drive motor (not shown) The roller 221 is rotated, and the magnetic particles in the supply bottle 220 are dropped into the magnetic brush charging device 120 in one time. It is also possible to control the image forming apparatus to be in an operating state by removing the empty supply bottle 220 after supply and setting a new supply bottle 220. In addition, a supply signal such as blinking of a lamp is displayed on the operation unit (not shown) from the control unit at regular intervals, the supply bottle 220 is set on the magnetic brush charging device 120, and an open / close lid (not shown) on the bottom of the supply bottle 220 is opened. Then, magnetic particles may be supplied.

  The dropped magnetic particles are conveyed by the rotating charging sleeve 120a, scraped off from the surface of the charging sleeve 120a by the scraper 123, and replenished to the bottom of the magnetic brush charging device 120. Accordingly, the used magnetic particles stored in the magnetic brush charging device 120 are overflowed from the discharge port 125 by the stirring screw 124 rotated counterclockwise, and the common magnetic particle recovery container 300 is passed through the duct DB. To be recovered. At this time, the supply amount of the magnetic particles supplied from the supply bottle 220 into the magnetic brush charging device 120 is preferably 20 to 50% by mass with respect to all the magnetic particles stored in the magnetic brush charging device 120. If the amount is less than 20% by mass, the amount of newly supplied magnetic particles is so small that there is no exchange effect and good charging is not performed. If the amount exceeds 50% by mass, new magnetic particles overflow.

  As described above, good charging performance is maintained for a long time without deterioration of the magnetic particles in the charging device.

  FIG. 4 is a cross-sectional view showing an example of an image forming apparatus having a magnetic brush charger. In FIG. 4, reference numeral 50 denotes a photosensitive drum (photosensitive member) which is an image carrier. An organic photosensitive layer is coated on the drum, and a photosensitive member having the structure of the present invention is applied to the photosensitive drum. Is done. Reference numeral 52 denotes a magnetic brush charger, which can uniformly charge the circumferential surface of the photosensitive drum 50 (charging process). Prior to charging by the charger 52, in order to eliminate the history of the photoconductor in the previous image formation, exposure by the exposure unit 51 using a light emitting diode or the like may be performed to neutralize the peripheral surface of the photoconductor.

  After uniform charging of the photoreceptor, image exposure based on the image signal is performed by the image exposure unit 53 (image exposure process). The image exposure unit 53 in this figure uses a laser diode (not shown) as an exposure light source. Scanning on the photosensitive drum is performed by the light whose optical path is bent by the reflection mirror 532 through the rotating polygon mirror 531 and the fθ lens, and an electrostatic latent image is formed.

  The electrostatic latent image is then developed by the developing device 54 (development process). A developing device 54 containing a developer composed of toner and carrier is provided on the periphery of the photosensitive drum 50, and development is performed by a developing sleeve 541 that contains a magnet and rotates while holding the developer. The developer is, for example, a carrier composed of the above-mentioned ferrite as a core and coated with an insulating resin around it, and a coloring material such as carbon black, a charge control agent, and a low molecular weight polyolefin mainly composed of the above-mentioned styrene acrylic resin. It consists of toner with silica, titanium oxide, etc. added externally to the particles. The developer is regulated to a layer thickness of 100 to 600 μm on the developing sleeve 541 by a layer forming means (not shown) and conveyed to the developing area. Then, development is performed. At this time, usually, development is performed by applying a DC bias between the photosensitive drum 50 and the developing sleeve 541 and, if necessary, an AC bias voltage. Further, the developer is developed in contact with or not in contact with the photoreceptor.

  The transfer material (also referred to as recording paper) P is fed to the transfer area by the rotation operation of the paper feed roller 57 at the time when the transfer timing is ready after image formation.

  In the transfer area, a transfer roller (transfer device) 58 is pressed against the peripheral surface of the photosensitive drum 50 in synchronization with the transfer timing, and the transferred transfer material P is sandwiched and transferred (transfer process).

  Next, the transfer material P is neutralized by a separation brush (separator) 59 brought into a pressure contact state almost simultaneously with the transfer roller, separated by the peripheral surface of the photosensitive drum 50, conveyed to the fixing device 60, and pressed against the heat roller 601. After the toner is welded by heating and pressurizing the roller 602 (fixing step), the toner is discharged to the outside of the apparatus via the discharge roller 61. The transfer roller 58 and the separation brush 59 are separated from the peripheral surface of the photosensitive drum 50 after the transfer material P has passed, and prepare for the formation of the next toner image.

  On the other hand, after the transfer material P is separated, the photosensitive drum 50 is subjected to removal and cleaning of residual toner by pressure contact of the cleaning blade 621 of the cleaning device 62, and again after being subjected to charge removal by the exposure unit 51 and charging by the charger 52. Enter the image forming process.

  Reference numeral 70 denotes a detachable process cartridge in which a photoconductor, a charger, a transfer device / separator, and a cleaning device are integrated.

  As the image forming apparatus, the above-described photosensitive member and components such as a developing device and a cleaning device may be integrally coupled as a process cartridge, and this unit may be configured to be detachable from the apparatus main body. In addition, a process cartridge is formed by integrally supporting at least one of a charger, an image exposure device, a developing device, a transfer or separation device, and a cleaning device together with a photosensitive member, and a single unit that is detachable from the apparatus main body. It is good also as a structure which can be attached or detached using guide means, such as a rail of an apparatus main body.

  When the image forming apparatus is used as a copying machine or a printer, image exposure is performed by irradiating a photosensitive member with reflected light or transmitted light from a document, or by reading a document with a sensor and generating a laser beam according to this signal. Scanning, driving the LED array, or driving the liquid crystal shutter array and irradiating the photosensitive member with light are performed.

  When used as a facsimile printer, the image exposure unit 13 performs exposure for printing received data.

  The electrophotographic photosensitive member of the present invention is generally applicable to electrophotographic apparatuses such as an electrophotographic copying machine, a laser printer, an LED printer, and a liquid crystal shutter printer, and further displays, recordings, light printing, plate making and the like using electrophotographic technology. It can be widely applied to apparatuses such as facsimiles.

  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”.

Example 1
Preparation of charge injection layer coating liquid A As a charge injection layer coating liquid, the following structural formula

Disperse 50 parts of antimony-doped tin oxide fine particles (T1: manufactured by Mitsubishi Materials Corp.) and 150 parts of ethanol surface-treated with a fluorine atom-containing compound in a sand mill for 66 hours. 20 parts of fluoroethylene fine particles (volume average particle size 0.18 μm) were added and dispersed for 2 hours. Thereafter, 25 parts of a resol type phenol resin (trade name: PL-4804, amine compound catalyst used, manufactured by Gunei Chemical Co., Ltd.) was dissolved as a resin component to prepare a charge injection layer coating solution A.

Preparation of charge injection layer coating liquid B In preparation of charge injection layer coating liquid A, 50 to 20 parts of antimony-doped tin oxide fine particles surface-treated with the fluorine atom-containing compound described in the above [Chemical Formula 5] (7% treatment amount). Except that 30 parts of antimony-doped tin oxide fine particles (20%) surface-treated with methyl hydrogen silicone oil (trade name KF99, manufactured by Shin-Etsu Silicone Co., Ltd.) were further added and dispersed. A charge injection layer coating solution B was prepared in exactly the same manner as described above.

Preparation of charge injection layer coating liquid C In preparation of charge injection layer coating liquid A, instead of antimony-doped tin oxide fine particles surface-treated with the fluorine atom-containing compound described in [Chemical Formula 5], antimony dope before surface treatment was applied. 50 parts of tin oxide fine particles (trade name T-1, manufactured by Mitsubishi Materials Corporation), and further the fluorine atom-containing compound (trade name LS-1090, manufactured by Shin-Etsu Silicone Co., Ltd.) described in [Chemical Formula 5] above. 5 parts, 5 parts of methyl hydrogen silicone oil (trade name KF-99, manufactured by Shin-Etsu Silicone Co., Ltd.) was added and dispersed in the same manner as in the charge injection layer coating liquid A, except that it was dispersed. Was made.

Preparation of Charge Injection Layer Coating Solution D Charge Injection Layer Coating Solution D except that PR-53123 (manufactured by Sumitomo Durez Co., Ltd.) was used instead of phenol resin PL-4804 in the preparation of charge injection layer coating solution B. A charge injection layer coating solution D was prepared in exactly the same manner as B.

Preparation of charge injection layer coating solution E Charge preparation layer coating solution B except that PR-50626 (manufactured by Sumitomo Durez Co., Ltd.) was used instead of phenol resin PL-4804 in the preparation of charge injection layer coating solution B. A charge injection layer coating solution E was prepared in exactly the same manner as B.

Preparation of charge injection layer coating solution F The following composition was dispersed to prepare a charge injection layer coating solution F.

Bisphenol C-type polycarbonate 10 parts 4-Methoxy-4 '-(4-methyl-α-phenylstyryl) triphenylamine 3 parts Tin oxide 5 parts Tetrahydrofuran 500 parts Next, a mixed compound of the general formula A as follows A photoconductor containing was prepared.
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 18 μm.

<Charge injection layer A>
The charge injection layer coating solution A is formed on the charge transport layer by a circular amount-regulating coating apparatus, and is cured by heating at 110 ° C. for 60 minutes to form a charge injection layer having a dry film thickness of 5.0 μm. Thus, a photoreceptor 1A was produced.

Preparation of photoconductors 2A to 14A In the photoconductor 1A, the same procedure was performed except that the charge generation material, the compound of the charge transport material, the amount of the compound, the thickness of the charge transport layer, and the charge injection layer were changed as shown in Table 1. Photoconductors 2A to 14A were prepared.

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%.

Production of Photoreceptor 18A Photoreceptor 18A was produced in the same manner as in Photoreceptor 1A, except that the charge injection layer was not applied and the thickness of the charge transport layer was 24 μm.

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
The photoreceptors 1A to 18A obtained as described above are respectively mounted on a remodeling machine of a reverse development type digital copying machine “Konica 7050” manufactured by Konica Corporation, in which a charging roller having the following configuration is incorporated. 80% RH) and low-temperature and low-humidity (10 ° C., 20% RH) environments were evaluated with different evaluation items. The evaluation results are shown in Table 2.

Charging roller As the material for the conductive elastic layer, polynorbornene rubber / carbon black / naphthenic oil and, if necessary, vulcanizing agent, vulcanization accelerator, additive, etc. are mixed and prepared, filled with mold, and conductive An elastic elastic layer was formed. On this layer, it is immersed in a composition liquid consisting of polyester urethane as a coating layer forming material, resin powder having a particle diameter of about 0.5 μm, carbon black, and a solvent (MEK / dimethylformamide), coating, drying and heating. Treatment to form a coating layer composed of a urethane layer. 1 was obtained. The resistance of the conductive elastic layer was 3.2 × 10 ⁴ Ωcm, the resistance of the coating layer was 5.2 × 10 ⁵ Ωcm, and the surface roughness of the charging roller was 10-point average roughness Rz of 0.1. .

Photoconductor linear velocity: 280 mm / sec
Exposure condition Exposure part potential target: Set to an exposure amount to be less than -50V.

Exposure beam: Image exposure was performed with a dot density of 800 dpi (dpi is the number of dots per 2.54 cm). The laser beam spot area: 0.8 × 10- ⁹ m ^2, laser 780nm semiconductor laser using transfer conditions: corotron electrodes using electrostatic transfer and separation conditions: using the separation means separating the electrodes of applying an AC bias Cleaning: A rubber elastic blade was used to adjust the contact angle to the photosensitive member: 20 ° and the contact load: 20 (g / cm).

Evaluation item and evaluation method Evaluation item and evaluation criteria Evaluation of residual potential (change in potential of solid black image)
Under low-temperature and low-humidity (10 ° C, 20% RH) and high-temperature, high-humidity (HH: 30 ° C, 80% RH) environments, a character image with a pixel rate of 7%, a halftone image, a solid white image, and a solid black image are each 1 / The original image in four equal parts was copied in 10,000 sheets in the single sheet intermittent mode at A4, and the potential change (| ΔV |) of the solid black image part at the development position after the initial and 10,000 sheets was evaluated. . The smaller the | ΔV |, the smaller the increase in the residual potential.

A: Potential change in solid black image portion | ΔV | is less than 50 V (good)
○: Potential change | ΔV | of solid black image portion is 50 V or more and 150 V or less (no problem in practical use)
×: The potential change | ΔV | of the solid black image portion is larger than 150 V (practically problematic)
Evaluation of charging potential (change in potential of solid white image)
Under low-temperature and low-humidity (10 ° C, 20% RH) and high-temperature, high-humidity (HH: 30 ° C, 80% RH) environments, a character image with a pixel rate of 7%, a halftone image, a solid white image, and a solid black image are each 1 / The original image in four equal parts was copied in 10,000 sheets in the single sheet intermittent mode at A4, and the potential change (| ΔV |) of the solid white image portion at the development position after the initial and 10,000 sheets was evaluated. . The smaller | ΔV | is, the smaller the change in charging potential is.

A: Potential change | ΔV | of solid white image portion is less than 50 V (good)
○: Potential change | ΔV | in a solid white image portion is 50 V or more and 150 V or less (no problem in practical use)
×: The potential change | ΔV | of the solid white image portion is larger than 150 V (practically problematic)
Image density: Evaluation at low temperature and low humidity (LL: 10 ° C., 20% RH), high temperature and high humidity (HH: 30 ° C., 80% RH) Measured using Macbeth RD-918. The relative reflection density was measured with the paper reflection density set to “0”. As the residual potential increases on multiple copies, the image density decreases. Measurements were taken at the solid black image portion after 10,000 copies each.

A: Black solid image is higher than 1.2 for both low temperature and low humidity and high temperature and high humidity (good)
○: Black solid image of 1.0 or more and 1.2 or less for both low temperature and low humidity and high temperature and high humidity (no problem in practical use)
×: Black solid image is less than 1.0 in either low temperature and low humidity or high temperature and high humidity (practical problem)
Fog; evaluated at low temperature and low humidity (LL: 10 ° C., 20% RH), and high temperature and high humidity (HH: 30 ° C., 80% RH). The reflection density was evaluated by a relative density (the density of A4 paper not copied is 0.000). Measurements were taken at the solid black image portion after 10,000 copies each.

A: Concentration is less than 0.010 (good) for both low temperature and low humidity and high temperature and high humidity
○: Concentration of 0.010 or more and 0.020 or less for both low temperature and low humidity and high temperature and high humidity
X: Concentration is higher than 0.020 at either low temperature and low humidity or high temperature and high humidity (a level that causes practical problems)
Dielectric breakdown: evaluated at low temperature and low humidity (LL: 10 ° C., 20% RH), high temperature and high humidity (30 ° C., 80% RH) ○: No dielectric breakdown of the photoconductor due to charge leakage at LL or HH.

  X: Dielectric breakdown of the photoreceptor due to charge leakage occurred at LL or HH.

Periodic image defects (high temperature and high humidity (30 ° C, 80% RH))
The periodicity coincided with the period of the photoconductor, and the number of visible black spots and black streak-like image defects per A4 size was determined.

A: Frequency of image defects of 0.4 mm or more: All copy images are 5 / A4 or less (good)
○: Frequency of image defects 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 image defects of 0.4 mm or more: 11 or more A4 or more occurred (practical problem)
Sharpness The sharpness of the image was evaluated by squashing characters by displaying images in both low temperature and low humidity (10 ° C., 20% RH) and high temperature, high humidity (30 ° C., 80% RH) environments. 3-point and 5-point character images were formed and evaluated according to the following criteria.

◎: No image blurring, 3 points and 5 points are clear and easy to read ○: Image blurring is minor, 3 points are partially unreadable, 5 points are clear and easy ×: Image blur occurs, 3 points are almost unreadable, 5 points are partially or completely unreadable

  From Table 2, the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the general formula (1) of the present invention and the distribution based on n is represented by x, and the composition ratio of the compound of the 2-position component is represented by y. Then, the photoconductors 1A to 14A using a mixed compound with x + y of 99% or less as a charge transport material and having a charge injection layer are excellent in the residual potential and charge potential stability at high temperature and high humidity and low temperature and low humidity. Therefore, the image density is sufficient and the fog density is small. In addition, dielectric breakdown does not occur, and the improvement effect of black spots etc. is remarkable, and as a result, an electrophotographic image with good sharpness is obtained. On the other hand, the photoconductor 15A using only a low molecular weight compound of n = 0 has a large residual potential increase, an image density is lowered, dielectric breakdown occurs, and sharpness is also lowered. 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) having a composition ratio of n = 1 and n = 2 of 50% as a charge transport material is also used as a charge transport material binder resin. Since the solubility is insufficient, the variation of the charging potential is large, fogging occurs, and as a result, the sharpness is also lowered. Moreover, dielectric breakdown and black spots have also occurred. Further, the photoconductor 18A having no charge injection layer frequently causes dielectric breakdown and black spots, has a high fog density, and deteriorates sharpness.

Example 2
A photoreceptor containing the mixed compound of the general formula B was produced as follows.
Preparation of photoreceptor 1B <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 and 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 (4)) 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 18 μm.

<Charge injection layer A>
The charge injection layer coating solution A is formed on the charge transport layer by a circular amount-regulating coating apparatus, and is cured by heating at 110 ° C. for 60 minutes to form a charge injection layer having a dry film thickness of 5.0 μm. Thus, a photoreceptor 1B was produced.

Preparation of photoconductors 2B to 14B In the photoconductor 1B, the charge generation material, the compound of the charge transport material, the amount of the compound, the thickness of the charge transport layer, and the charge injection layer were changed in the same manner as shown in Table 3. Photoconductors 2B to 14B were prepared. However, the prescriptions of the charge injection layers A to G are the same as described above.

Production of Photoreceptor 15B In the production of Photoreceptor 1B, a component (component purity) of n = 0 of Compound 11B (m = 0) synthesized separately by a known method from a charge transport material (the compound of Synthesis Example (5)). Photoconductor 15B was prepared in the same manner except that the charge transport material was replaced by 99% or more.

Production of Photoreceptor 16B In production of Photoreceptor 1B, the charge transport material (the compound of Synthesis Example (5)) was separated from the compound of Synthesis Example (5) by liquid chromatography to obtain Compound 11B (m = 0). The photoconductor 16B was prepared in the same manner except that it was replaced with a charge transport material having only n = 3 (the component purity was greater than 99%), but the charge transport material was not compatible with the binder resin and deposited. Thus, a photoconductor that can be evaluated was not obtained.

Production of Photoreceptor 17B In production of Photoreceptor 1B, the charge transport material (the compound of Synthesis Example (5)) was separated from the compound of Synthesis Example (5) by liquid chromatography to obtain Compound 11B (m = 0). The photoconductor 17B was prepared in the same manner except that it was used instead of the charge transport material of the mixed compound in which the composition ratio of n = 2 and n = 3 was 50%.

Production of Photoreceptor 18B Photoreceptor 18B was produced in the same manner as in Photoreceptor 1B, except that the charge injection layer was not applied and the thickness of the charge transport layer was 24 μm.

  In the table, Y and Z are the same as in Table 1.

  (X + y) is the same as in Table 1.

  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 2
The photoreceptors 1B to 18B obtained as described above were evaluated in the same manner except that the conditions of Evaluation 1 were changed as follows. The evaluation results are shown in Table 4.

<Change of evaluation conditions>
Photoconductors 1B to 18B were evaluated in the same manner as in Evaluation 1 except that the charging roller used in Evaluation 1 was replaced with a magnetic brush charger and the linear velocity of the photoconductor was modified to 140 mm / sec.

(Magnetic brush charger)
It has the structure of FIG.

Production of magnetic particles Magnetic particles forming a magnetic brush for charging were produced as follows.

Fe ₂ O ₃ : 50 mol%
CuO: 24 mol%
ZnO: 24 mol%
The above was pulverized and mixed to form a slurry by adding a dispersant, a binder, and water, followed by granulation with a spray dryer and classification, followed by firing at 1125 ° C. The obtained magnetic particles were crushed and then classified to obtain magnetic particles 1 having a volume average particle size of 27 μm. The resistivity of the magnetic particles was 2 × 10 ⁷ Ωcm, and the magnetization strength was 65 emu / g.

Measurement Method of Volume Average Particle Size of Magnetic Particles The measurement of the volume average particle size of a carrier is typically performed by a laser diffraction particle size distribution measuring apparatus “HELOS” equipped with a wet disperser (SYMPATEC). Manufactured).

After tapping put assay magnetic particles resistivity ([Omega] cm) in a container having a sectional area of 0.50 cm ^2, a load of 1 kg / cm ² on packed particles, between the load and a bottom electrode A value obtained by reading a current value when a voltage generating an electric field of 1000 V / cm is applied to the.

Charging conditions Charging sleeve; 10 mmφ stainless steel Voltage applied to charging sleeve; AC voltage superimposed on DC voltage 450 V Charged magnetic particle amount; 250 mg / cm ²
Charge sleeve / photoconductor linear velocity ratio; 0.8

  From Table 4, the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the general formula (1) of the present invention and the distribution based on n is represented by x, and the composition ratio of the compound of the 2-position component is represented by y. Then, the photoconductors 1B to 14B using a mixed compound with x + y of 99% or less as a charge transport material and having a charge injection layer are excellent in the residual potential and charge potential stability at high temperature and high humidity and low temperature and low humidity. Therefore, the image density is sufficient and the fog density is small. In addition, dielectric breakdown does not occur, and the improvement effect of black spots etc. is remarkable, and as a result, an electrophotographic image with good sharpness is obtained. On the other hand, the photoconductor 15B using only a low molecular weight compound of n = 0 has a large residual potential increase, an image density decreases, dielectric breakdown occurs, and sharpness also decreases. In addition, in the case of the photoreceptor 16B using only a high molecular weight compound of n = 3, the solubility with the binder resin was poor, and there was almost no sensitivity and the like, which was not worthy of evaluation. The photoconductor 17B using the compound 11B (m = 0) in which the compound ratio of n = 2 and n = 3 is 50% as the charge transport material is also insufficient in the solubility of the charge transport material in the binder resin. For this reason, the fluctuation of the charging potential is large, fogging occurs, and as a result, sharpness is also lowered. Moreover, dielectric breakdown and black spots have also occurred. In addition, the photoconductor 18B having no charge injection layer frequently has dielectric breakdown, black spots, high fog density, and sharpness is deteriorated.

Example 3
A photoreceptor containing the mixed compound of the general formula C was produced as follows.
Preparation of photoreceptor 1C <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 (6)) 150 parts Binder resin: Bisphenol Z-type polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Co., Ltd.) 300 parts Antioxidant (Sanol LS2626: 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 18 μm.

<Charge injection layer A>
The charge injection layer coating solution A is formed on the charge transport layer by a circular amount-regulating coating apparatus, and is cured by heating at 110 ° C. for 60 minutes to form a charge injection layer having a dry film thickness of 5.0 μm. Thus, a photoreceptor 1C was produced.

Production of Photoreceptor 2C Photoreceptor 2C was produced in the same manner as in Photoreceptor 1C, except that the compound of the charge transport material was changed from the compound of Synthesis Example (6) to the compound of Synthesis Example (7).

Preparation of photoconductors 3C to 10C In preparation of photoconductor 1C, the same procedure was performed except that the charge generation material, the compound of the charge transport material, the amount of the compound, the thickness of the charge transport layer, and the charge injection layer were changed as shown in Table 5. Photoconductors 3C to 10C were prepared.

Production of Photoreceptor 11C In the production of Photoreceptor 1C, a compound obtained by separately synthesizing a charge transport material (the compound of Synthesis Example (6)) by a known method, a component having only n = 0 of chemical structure 17C (component purity is 99) Photoconductor 11C was prepared in the same manner except that it was used in place of the charge transport material of greater than%.

Production of Photoreceptor 12C In the production of Photoreceptor 1C, the charge transport material (the compound of Synthesis Example (6)) was separated from the component of Synthesis Example (6) by column chromatography, and n = Photoreceptor 12C was prepared in the same manner except that it was used in place of the charge transport material having only 5 components (component purity greater than 99%), but the charge transport material was not compatible with the binder resin and deposited. A photoconductor that can be evaluated was not obtained.

Production of Photoreceptor 13C In production of Photoreceptor 1C, the charge transport material (the compound of Synthesis Example (6)) was separated from the component of Synthesis Example (6) by liquid chromatography, and n = A photoconductor 13C was prepared in the same manner except that it was used in place of the charge transport material of the mixed compound in which the composition ratio of 4 and n = 5 was 50%.

Production of Photoreceptor 14C Photoreceptor 14C was produced in the same manner as in Photoreceptor 1C, except that the charge injection layer was not applied and the thickness of the charge transport layer was 24 μm.

  In the table, Y and Z are the same as in Table 1.

  (X + y) is the same as in Table 1.

  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 3
The photoreceptors 1C to 14C obtained as described above were evaluated by the same method as in Evaluation 1. The evaluation results are shown in Table 6.

  From Table 6, the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the general formula (1) of the present invention and the distribution based on n is represented by x, and the composition ratio of the compound of the 2-position component is represented by y. Then, the photoconductors 1C to 10C using a mixed compound with x + y of 99% or less as a charge transport material and having a charge injection layer are excellent in residual potential at high temperature and high humidity and low temperature and low humidity, and stability of charging potential. Therefore, the image density is sufficient and the fog density is small. In addition, dielectric breakdown does not occur, and the improvement effect of black spots etc. is remarkable, and as a result, an electrophotographic image with good sharpness is obtained. On the other hand, the photoconductor 11C using only a low molecular weight compound of n = 1 has a large residual potential increase, an image density is lowered, dielectric breakdown occurs, and sharpness is also lowered. Further, in the case of the photoreceptor 12C using only the compound having a high molecular weight of n = 5, the solubility with the binder resin was poor, and there was almost no sensitivity and the like and was not worthy of evaluation. Further, the photosensitive member 13C using a mixed compound having a composition ratio of n = 4 and n = 5 of the chemical structure 17C of 50% as the charge transport material is also insufficiently soluble in the binder resin of the charge transport material. The fluctuation of the charging potential is large, fogging occurs, and as a result, sharpness is also lowered. Moreover, dielectric breakdown and black spots have also occurred. In addition, the photoreceptor 14C having no charge injection layer frequently has dielectric breakdown and black spots, has a high fog density, and deteriorates sharpness.

1 is a diagram illustrating an example of an image forming apparatus using charging roller charging. It is a figure of a contact-type magnetic brush charging device. It is a figure which shows the relationship between the alternating current bias voltage and charging potential by the charging device of FIG. It is sectional drawing which shows an example of the image forming apparatus which has a magnetic brush charger.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Charging roller 2 Photosensitive drum 3 Developing device 4 Developing sleeve 5 Static elimination lamp 6 Transfer roller 7 Conveying belt 8 Conveying roller 20 Core metal 50 Photosensitive drum 51 Exposure unit 52 Magnetic brush charger 53 Image exposing unit 54 Developing unit 120 Magnetic brush Charging device 120a Charging sleeve 220 Supply bottle 300 Magnetic particle recovery container

Claims (17)

When a compound having the structure of the following general formula (1) and having a distribution based on n is used, the composition ratio of the maximum component of the compound is x, and the composition ratio of the component at the 2nd position is y, x + y is An electrophotographic photoreceptor comprising 99% or less of a mixed compound and having a charge injection layer.
General formula (1) X- (CTM group) _n -Y n = 0 to 10
In general formula (1), the CTM group is a charge transporting group.
X and Y are a hydrogen atom, a halogen atom, or a monovalent organic group n is 0 to 10 (provided that when both X and Y are a hydrogen atom and a halogen atom, n is 1 to 10) In the electrophotographic photosensitive member in which a charge generation layer having a charge generation material, a charge transport layer having a charge transport layer, and a charge injection layer are laminated on a conductive support, the charge transport layer has the structure of the above general formula (1). And a compound having a distribution based on n, wherein x is the maximum component composition ratio and x is the second component composition ratio, and x + y is 99% or less. An electrophotographic photosensitive member characterized by comprising: The electrophotographic photosensitive member according to claim 1, wherein x + y in the general formula (1) is in the following range.
30% ≦ x + y ≦ 99% The electrophotographic photosensitive member according to claim 1, wherein the mixed compound has a weight average molecular weight of 650 to 2500. The electrophotographic photosensitive member according to claim 4, wherein the mixed compound has a weight average molecular weight of 800 to 2,000. 6. The electrophotographic photosensitive member according to claim 3, wherein x + y is in the following range.
45% ≦ x + y ≦ 90% The electrophotographic photosensitive member according to claim 1, wherein the CTM group of the general formula (1), X, and Y have the following general formula A.

In the above 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 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 bonded to each other. Also good.

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 electrophotographic photosensitive member according to claim 1, wherein the CTM group, X, and Y of the general formula (1) has the following general formula B.

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), and R _{1 to} R ₃ represent a hydrogen atom or a substituted atom. , 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 0 or 1 respectively. The electrophotographic photosensitive member according to claim 7 or 8, wherein the divalent group containing the triarylamine group of A is a group of the following general formula (4).

In the general formula (4), Ar ₃ represents a substituted or unsubstituted monovalent aromatic group. The electrophotographic photosensitive member according to claim 9, wherein Ar ₃ is a group of the following general formula (5).

In 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. 9. The electrophotographic photosensitive member according to claim 7, 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 electrophotographic photosensitive member according to claim 8, wherein B is a group represented by the following general formula (7).

In General Formula (7), R ₄₁ , R ₄₂ , R ₄₃ , R ₄₄ , R ₄₅ , R ₅₁ , R ₅₂ , R ₅₃ , R ₅₄ , and R ₅₅ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. . However, at least one of R ₄₁ , R ₄₅ , R ₅₁ and R ₅₅ is an alkyl group having 1 to 4 carbon atoms. The electrophotographic photosensitive member according to any one of claims 1 to 6, wherein the CTM group, X and Y in the general formula (1) has the following general formula C.

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

In General Formula (8), Y is 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. The electrophotographic photosensitive member according to claim 1, wherein the charge injection layer contains conductive particles. When the compound having the structure of the general formula (1) and having a distribution based on n is used, the composition ratio of the maximum component of the compound is x, and the composition ratio of the component at the 2-position is y, x + y is An electrophotographic photosensitive member containing 99% or less of a mixed compound and having a charge injection layer, charging means for uniformly charging the electrophotographic photosensitive member in contact with the electrophotographic photosensitive member, and a charged electrophotographic photosensitive member A latent image forming means for forming an electrostatic latent image on the electrophotographic photosensitive member, a developing means for visualizing the electrostatic latent image on the electrophotographic photosensitive member, and a toner image visualized on the electrophotographic photosensitive member on a transfer material. And at least one of a transfer means for transferring the toner, a charge eliminating means for removing charges on the electrophotographic photosensitive member after the transfer, and a cleaning means for removing residual toner on the electrophotographic photosensitive member after the transfer. And can be detachably attached to the image forming apparatus main body. The process cartridge according to claim. A charging means for uniformly charging the electrophotographic photosensitive member in contact with the electrophotographic photosensitive member, a latent image forming means for forming an electrostatic latent image on the charged electrophotographic photosensitive member, and a static on the electrophotographic photosensitive member. In an image forming apparatus comprising developing means for developing an electrostatic latent image and transfer means for transferring a toner image visualized on the electrophotographic photosensitive member onto a transfer material, the electrophotographic photosensitive member is represented by the general formula When the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of (1) and having a distribution based on n is x, and the composition ratio of the compound of the 2-position component is y, x + y is 99% or less. An image forming apparatus comprising a mixed compound and having a charge injection layer. An image forming method comprising forming an electrophotographic image using the image forming apparatus according to claim 16.

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