JP2013254136A - Electrophotographic photoreceptor, electrophotographic image forming method, and electrophotographic image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly durable electrophotographic photoreceptor that is excellent in abrasion resistance and potential holding property, prevents an increase in residual potential and generation of an image memory, and is capable of forming good electrophotographic images stably for a long period; and an electrophotographic image forming method and an electrophotographic image forming apparatus using the electrophotographic photoreceptor.SOLUTION: An electrophotographic photoreceptor includes a charge generating layer, a charge transport layer, and a protective layer containing at least a charge transport material, which are sequentially laminated on a conductive support. The protective layer contains a triarylamine-based compound as the charge transport material; and a by-product triarylamine-based compound is contained in the amount ranging from 0 to 0.05 mass% relative to the triarylamine-based compound.

Description

  The present invention relates to an electrophotographic photoreceptor, an electrophotographic image forming method and an electrophotographic image forming apparatus using the electrophotographic photoreceptor.

  In recent years, organic photoreceptors containing organic photoconductive materials have been widely used for electrophotographic photoreceptors. Organic photoconductors are advantageous for inorganic photoconductors because it is easy to develop materials compatible with various exposure light sources from visible light to infrared light, the ability to select materials without environmental pollution, and low manufacturing costs. Is a point.

  On the other hand, since an electrophotographic photoreceptor (hereinafter also referred to as “photoreceptor”) is directly subjected to electrical or mechanical external force by charging, exposure, development, transfer, cleaning, etc., image formation is repeatedly performed. However, there is a demand for durability to stably maintain charging stability, potential holding property, and the like.

  In particular, in recent years, the demand for high-definition and high-quality images has increased in the trend of digitization, and toners having a small particle diameter by a polymerization method such as a dissolution suspension toner and an emulsion polymerization aggregation toner have become mainstream. These toners having a small particle diameter have a large adhesion force to the surface of the photoreceptor, and the removal of residual toner such as transfer residual toner attached to the surface of the photoreceptor is likely to be insufficient. In the cleaning method using a rubber blade, there are phenomena such as "toner slipping" where the toner passes through the blade, "blade curl" where the blade is reversed, or the generation of scratching noise between the photoconductor and the blade, so-called "blade squealing". Likely to happen. In order to solve the above-mentioned “toner slipping”, it is necessary to increase the contact pressure of the blade to the photosensitive member. However, the repeated use causes the surface of the electrophotographic photosensitive member to be worn and the durability is insufficient. A problem occurs. Further, it is required to have sufficient durability against deterioration caused by ozone and nitrogen oxides generated during charging.

  For these reasons, a technique for improving the mechanical strength by providing a protective layer (hereinafter also referred to as “surface layer”) on the surface of the photoreceptor has been proposed.

  Specifically, a polymerizable compound generally called a curable compound is used for the photosensitive member protective layer, and after coating, a polymerization reaction is performed to prevent surface abrasion or scratches due to friction of a cleaning blade or the like. Techniques for producing highly durable photoconductors have been proposed (see, for example, Patent Document 1 and Patent Document 2). In addition, a technique for improving mechanical strength by dispersing inorganic fine particles such as silica in a protective layer has been proposed (for example, see Patent Document 3).

  In recent years, the use of electrophotographic image forming apparatuses in the light printing field has been rapidly expanding, and electrophotographic photoreceptors are required to have higher durability and higher image quality. However, in response to these demands, the prior art cannot provide an electrophotographic photosensitive member that is sufficiently satisfactory in durability and image quality, and the electrophotographic photosensitive member is expected to have higher durability and higher image quality. It was rare.

  However, since the charge transport performance of the protective layer is inferior, the provision of the protective layer has a problem that the sensitivity characteristic as an electrophotographic photosensitive member is deteriorated as compared with an electrophotographic photosensitive member without a protective layer. . In order to solve this problem, charge transport performance can be provided by including a charge transport material in the protective layer.

  However, since the charge transport material of an organic compound generally has a plasticizing effect, the strength of the protective layer is reduced by the addition of the charge transport material. Thus, a technique for obtaining a protective layer having a charge transport function and excellent wear resistance has been disclosed. For example, protection by curing a radical polymerizable compound having a charge transport function, a radical polymerizable compound not having a charge transport function, and a metal oxide particle treated with a surface treatment agent having a polymerizable functional group by a polymerization reaction. A layer technology is disclosed (for example, see Patent Document 4). However, even with this technology, satisfactory charge transport performance was not obtained, and the wear resistance was not satisfactory.

  Further, here, metal oxide particles such as silicon oxide, aluminum oxide or titanium dioxide are added as metal oxide particles, but these metal oxide particles can be expected to have a certain effect on improving wear resistance. However, the hole transport performance is not sufficient, and the difference in image density due to the photoconductor cycle, that is, the so-called image memory is generated, which is not sufficient to achieve both wear resistance and image characteristics.

  On the other hand, triphenylamine compounds are known as charge transport materials (see, for example, Patent Document 5). However, the triphenylamine compound disclosed in Patent Document 5 has a problem that the charge transport performance is inferior due to impurities by-produced in the synthesis process, and even if added to the protective layer, the protective layer The effect of improving the charge transport performance was not sufficient.

JP 11-288121 A JP 2009-69241 A JP 2002-333733 A JP 2010-169725 A JP 2006-143720 A

  The present invention has been made in view of the above problems and circumstances, and its solution is excellent in wear resistance and potential retention, stable in the long term without any increase in residual potential and generation of image memory. It is another object of the present invention to provide a highly durable electrophotographic photosensitive member capable of forming a good electrophotographic image, an electrophotographic image forming method and an electrophotographic image forming apparatus using the electrophotographic photosensitive member.

  In order to solve the above problems, the present inventor suppresses the amount of impurities contained in the charge transport material to be contained in the protective layer to a specific amount or less in the process of examining the cause of the above problems. The inventors have found that the problem can be solved and have reached the present invention.

  That is, the present invention is solved by an electrophotographic photosensitive member having the following configuration.

  1. An electrophotographic photosensitive member in which a charge generation layer, a charge transport layer, and a protective layer containing at least a charge transport material are sequentially laminated on a conductive support, wherein the charge transport material is represented by the following general formula (1). The content of the compound represented by the following general formula (2) or the general formula (3) is 0 to 0.00 with respect to the compound represented by the general formula (1). An electrophotographic photosensitive member characterized by being in the range of 05 mass%.

（一般式（１）、一般式（２）及び一般式（３）中、Ｒ_１、Ｒ_２及びＲ_３は、各々独立に、水素原子、アルキル基、又はアルコキシ基を表す。ｌ及びｎは１〜５の整数を表し、ｍは１〜４の整数を表す。ｌ、ｍ及びｎが２以上の場合、Ｒ_１、Ｒ_２及びＲ_３は同一でも異なっていても良い。）

(In General Formula (1), General Formula (2), and General Formula (3), R ₁ , R _2, and R ₃ each independently represent a hydrogen atom, an alkyl group, or an alkoxy group. 1 represents an integer of 1 to 5, and m represents an integer of 1 to 4. When l, m, and n are 2 or more, R ₁ , R _2, and R ₃ may be the same or different.

  2. 2. The electrophotographic photosensitive member according to item 1, wherein the protective layer contains at least a resin component obtained by polymerizing a polymerizable compound and metal oxide particles.

  3. 3. The electrophotographic photosensitive member according to item 2, wherein the metal oxide particles are surface-treated with a surface treatment agent having a methacryloyl group or an acryloyl group.

  4). 4. The electrophotographic photosensitive member according to item 2 or 3, wherein the metal oxide particles are any one selected from tin oxide particles, titanium oxide particles, and zinc oxide particles.

  5. The content of the compound represented by the general formula (1) in the protective layer is in the range of 10 to 50 parts by mass with respect to 100 parts by mass of the resin component obtained by polymerizing the polymerizable compound. The electrophotographic photosensitive member according to any one of items 1 to 4, wherein the electrophotographic photosensitive member is characterized.

  6). An electrophotographic image forming method using the electrophotographic photosensitive member according to any one of items 1 to 5.

  7). An electrophotographic image forming apparatus comprising the electrophotographic photosensitive member according to any one of items 1 to 5.

  By using the electrophotographic photosensitive member of the present invention, the wear resistance is high, and it is possible to prevent an increase in residual potential and generation of a transfer memory by installing a protective layer, achieving stable potential retention, and long-term In addition, it is possible to provide a highly durable electrophotographic photosensitive member, an electrophotographic image forming method, and an electrophotographic image forming apparatus that can stably and satisfactorily form an electrophotographic image.

  The expression mechanism or action mechanism of the effect of the present invention is not clear, but is considered as follows.

  That is, when the triarylamine compound represented by the general formula (1) is synthesized by an ordinary synthesis method, the general formula (2) or the general formula is obtained by oxidation or coupling of raw materials, reaction intermediates, and reaction products. The compound (3) is produced as a by-product. The compounds of the general formula (2) and the general formula (3) have a lower ionization potential than the compound of the general formula (1), so that they easily become carrier traps and deteriorate the electrical characteristics of the electrophotographic photosensitive member even with a very small amount. it is conceivable that. Therefore, in the synthesis of the compound represented by the general formula (1), the content of the compound represented by the general formula (2) or the general formula (3) is compared with the compound represented by the general formula (1). It is considered that the deterioration of the electrical characteristics could be prevented by refining until 0.05 mass% or less.

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

  The electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member in which a charge generation layer, a charge transporting layer, and a protective layer containing at least a charge transporting material are sequentially laminated on a conductive support, And a compound represented by the following general formula (1) and represented by the following general formula (2) or general formula (3) with respect to the compound represented by the general formula (1) The content of the compound is in the range of 0 to 0.05% by mass. This feature is a technical feature common to the inventions according to claims 1 to 7.

  As an embodiment of the present invention, it is preferable that the protective layer contains at least a resin component obtained by polymerizing a polymerizable compound and metal oxide particles because an effect of improving the wear resistance of the protective layer is obtained.

  Furthermore, in the present invention, it is preferable that the metal oxide particles are surface-treated with a surface treatment agent having a methacryloyl group or an acryloyl group because the effect of increasing the strength of the protective layer and improving the wear resistance can be obtained. .

  Further, in the present invention, the metal oxide particles are any one selected from tin oxide particles, titanium oxide particles, and zinc oxide particles, which has the effect of increasing the strength of the protective layer and improving the wear resistance. Since it is obtained, it is preferable.

  In the present invention, the content of the compound represented by the general formula (1) in the protective layer is 10 to 50 parts by mass with respect to 100 parts by mass of the resin component obtained by polymerizing the polymerizable compound. It is preferable to be within the range because the effect of improving the charge transport performance of the protective layer and suppressing the increase of the residual potential can be obtained.

  The electrophotographic photoreceptor of the present invention can be suitably used for an electrophotographic image forming method. Further, it can be suitably provided in an electrophotographic image forming apparatus.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In the present application, “to” is used in the sense of including the numerical values described before and after the lower limit value and the upper limit value.

[Compound represented by the general formula (1)]
The electrophotographic photosensitive member of the present invention contains the compound represented by the general formula (1) in the protective layer, and the general formula (2) or the compound represented by the general formula (1). Content of the compound represented by General formula (3) exists in the range of 0-0.05 mass%, It is characterized by the above-mentioned.

In general formula (1), general formula (2), and general formula (3), R ₁ , R _2, and R ₃ each independently represent a hydrogen atom, an alkyl group, or an alkoxy group. l and n represent the integer of 1-5, m represents the integer of 1-4. When l, m, and n are 2 or more, R ₁ , R _2, and R ₃ may be the same or different.

  Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. In addition, examples of the alkoxy group include a methoxy group and an ethoxy group.

In particular, at least one of R ₁ , R ₂ and R ₃ preferably has a propyl group, a butyl group or a pentyl group.

  The compound represented by the general formula (1) is a hole transporting compound that transports charge carriers in the protective layer, and has a molecular weight of 450 or less (preferably 320 or more and 420 or less). It is possible to enter the voids of the cross-linked cured resin layer of the layer. For this reason, it is possible to smoothly inject charge carriers from the charge transport layer without deteriorating the wear resistance of the protective layer, and on the surface of the protective layer without causing an increase in residual potential and occurrence of transfer memory. Charge can be transported.

  The compounds represented by the general formula (2) and the general formula (3) are synthesized as by-products in the process of synthesizing the compound represented by the general formula (1).

  The compound of the general formula (1) is usually synthesized by a coupling reaction of a diarylamine and an aryl halide. At this time, a compound represented by the general formula (2) or the general formula (3) is generated. The crude product of the compound represented by the general formula (1) is purified, and the content of the compound represented by the general formula (2) or the general formula (3) as an impurity is represented by the general formula (1). By setting the amount to 0.05% by mass or less based on the compound to be produced, the influence of impurities can be suppressed to a level where there is no practical problem. As a purification method, distillation or column chromatography can be used.

  Which compound of general formula (2) or general formula (3) is formed depends on the synthesis method. That is, in the following method (Synthesis Method A), a compound of the general formula (2) is generated, and in the following method (Synthesis Method B), a compound of the general formula (3) is generated. Both compounds have substantially the same effect on the electrophotographic characteristics, and an unexpected improvement effect can be obtained by setting the content to 0.05% by mass or less with respect to the compound represented by the general formula (1). I found that the effect disappeared.

（但し、上記式中、Ｘは塩素原子、臭素原子又はヨウ素原子を表し、Ｒ_１、Ｒ_２及びＲ_３は上記一般式（１）及び一般式（２）と同義の基を表す。ｌ及びｎは１〜５の整数を表し、ｍは１〜４の整数を表す。ｌ、ｍ及びｎが２以上の場合、Ｒ_１、Ｒ_２及びＲ_３は同一でも異なっていても良い。） (Synthesis Method A)

(However, in the above formulas, X represents a chlorine atom, a bromine atom or an iodine atom, .l R _1, R ₂ and R ₃ represents the general formulas (1) and (2) synonymous groups and n represents an integer of 1 to 5, and m represents an integer of 1 to 4. When l, m, and n are 2 or more, R ₁ , R _2, and R ₃ may be the same or different.

（但し、上記式中、Ｘは塩素原子、臭素原子又はヨウ素原子を表し、Ｒ_１、Ｒ_２及びＲ_３は上記一般式（１）及び一般式（３）と同義の基を表す。ｌ及びｎは１〜５の整数を表し、ｍは１〜４の整数を表す。ｌ、ｍ及びｎが２以上の場合、Ｒ_１、Ｒ_２及びＲ_３は同一でも異なっていても良い。） (Synthesis method B)

(However, in the above formulas, X represents a chlorine atom, a bromine atom or an iodine atom, .l R _1, R ₂ and R ₃ represents the general formula (1) and the general formula (3) Synonymous groups and n represents an integer of 1 to 5, and m represents an integer of 1 to 4. When l, m, and n are 2 or more, R ₁ , R _2, and R ₃ may be the same or different.

Specific examples of the compound represented by the general formula (1) are shown below.

上記化合物は公知の合成方法、例えば、特開２００６−１４３７２０号公報等に記載された方法で合成することができる。

The above compound can be synthesized by a known synthesis method, for example, a method described in JP-A-2006-143720.

[Metal oxide particles]
The protective layer according to the present invention preferably contains metal oxide particles. The metal oxide particles are preferably metal oxide particles having a volume resistivity of 1 × 10 ³ to 1 × 10 ¹¹ Ω · cm. As the metal oxide particles having the above-mentioned volume resistivity characteristics, for example, any of the metal oxide particles including transition metals, for example, silica (silicon oxide), magnesium oxide, zinc oxide, lead oxide, alumina ( Examples include metal oxide particles such as aluminum oxide), zirconium oxide, tin oxide, titania (titanium oxide), niobium oxide, molybdenum oxide, and vanadium oxide. Among these, tin oxide particles, titanium oxide particles, and zinc oxide particles are exemplified. preferable.

  The volume resistivity (Ω · cm) of the metal oxide particles is determined as follows.

  An electrical resistance is generally used as a measure of the conductivity of a substance. A value indicating this resistance per unit volume (1 cm × 1 cm × 1 cm) is a volume resistivity (Volume Resistivity, unit Ω · cm).

  That is, it is obtained by passing a constant current I (A) through the cross-sectional area W × t and measuring the potential difference V (V) between the electrodes separated by the distance L.

Definition of volume resistivity (Ω · cm) Cross-sectional area = W x t
Resistance R = V / I
Volume resistivity VR (Ω · cm) = (W × t / L) × (V / I)
The volume resistivity (Ω · cm) of the metal oxide fine particles described in the present invention is such that a container having electrodes arranged in parallel at intervals of 2 mm is filled with metal oxide fine particles and the like, and the direct current resistance at a potential difference of 500 V between both electrodes. Was measured by “4329A High Resistance Meter” manufactured by Yokogawa Hewlett-Packard Co., Ltd.

  The method for producing metal oxide particles according to the present invention is not particularly limited, and particles produced by a known production method can be used.

  The number average primary particle size of the metal oxide particles according to the present invention is preferably in the range of 1 to 300 nm. Especially preferably, it exists in the range of 3-100 nm.

  The number average primary particle size of the metal oxide particles is a photographic image (excluding aggregated particles) taken with a scanning electron microscope (manufactured by JEOL Ltd.) with a magnification of 10000 times, and 300 particles randomly taken by a scanner. The automatic image processing analyzer “LUZEX AP (Nireco Co., Ltd.)” software version Ver. The number average primary particle size was calculated using 1.32.

[Surface-treated metal oxide particles]
The metal oxide particles according to the present invention are preferably surface-treated with a treatment agent having a radical polymerizable functional group, particularly a surface treatment agent having an acryloyl group or a methacryloyl group.

  Examples of the surface treatment agent having an acryloyl group or a methacryloyl group include the following compounds.

_{S-1 CH 2 = CHSi (} CH 3) (OCH 3) 2
_{S-2 CH 2 = CHSi (} OCH 3) 3
S-3 CH ₂ = CHSiCl _{3
S-4 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-5 CH 2 = CHCOO (} CH 2) 2 Si (OCH 3) 3
_{S-6 CH 2 = CHCOO (} CH 2) 3 Si (CH 3) (OCH 3) 2
_{S-7 CH 2 = CHCOO (} CH 2) 3 Si (OCH 3) 3
_{S-8 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) Cl 2
_{S-9 CH 2 = CHCOO (} CH 2) 2 SiCl 3
_{S-10 CH 2 = CHCOO (} CH 2) 3 Si (CH 3) Cl 2
S-11 CH ₂ = CHCOO (CH ₂ ) ₃ SiCl _{3
S-12 CH 2 = C (} CH 3) COO (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-13 CH 2 = C (} CH 3) COO (CH 2) 2 Si (OCH 3) 3
_{S-14 CH 2 = C (} CH 3) COO (CH 2) 3 Si (CH 3) (OCH 3) 2
_{S-15 CH 2 = C (} CH 3) COO (CH 2) 3 Si (OCH 3) 3
_{S-16 CH 2 = C (} CH 3) COO (CH 2) 2 Si (CH 3) Cl 2
_{S-17 CH 2 = C (} CH 3) COO (CH 2) 2 SiCl 3
_{S-18 CH 2 = C (} CH 3) COO (CH 2) 3 Si (CH 3) Cl 2
_{S-19 CH 2 = C (} CH 3) COO (CH 2) 3 SiCl 3
_{S-20 CH 2 = CHSi (} C 2 H 5) (OCH 3) 2
S-21 CH ₂ ═C (CH ₃ ) Si (OCH ₃ ) _{3
S-22 CH 2 = C (} CH 3) Si (OC 2 H 5) 3
_{S-23 CH 2 = CHSi (} OCH 3) 3
_{S-24 CH 2 = C (} CH 3) Si (CH 3) (OCH 3) 2
_{S-25 CH 2 = CHSi (} CH 3) Cl 2
_{S-26 CH 2 = CHCOOSi (} OCH 3) 3
_{S-27 CH 2 = CHCOOSi (} OC 2 H 5) 3
_{S-28 CH 2 = C (} CH 3) COOSi (OCH 3) 3
_{S-29 CH 2 = C (} CH 3) COOSi (OC 2 H 5) 3
_{S-30 CH 2 = C (} CH 3) COO (CH 2) 3 Si (OC 2 H 5) 3

また、表面処理剤の金属酸化物粒子への処理量は、処理前の金属酸化物粒子１００質量部に対して表面処理剤０．１〜２００質量部の範囲内が好ましい。

Moreover, the processing amount to the metal oxide particles of the surface treatment agent is preferably in the range of 0.1 to 200 parts by mass of the surface treatment agent with respect to 100 parts by mass of the metal oxide particles before the treatment.

[Production method of surface-treated metal oxide particles]
Hereinafter, a method for producing metal oxide particles surface-treated with a treating agent having a radical polymerizable functional group will be described by taking titanium oxide particles as an example.

  The titanium oxide particles surface-treated with the treatment agent having a radically polymerizable functional group according to the present invention are surface-treated with a silane compound having the radically polymerizable functional group (the exemplified compound) and the like. Can be obtained. In performing the surface coating treatment, a wet media dispersion type apparatus is used by using 0.1 to 200 parts by mass of a silane compound as a surface treatment agent and 50 to 5000 parts by mass of a solvent with respect to 100 parts by mass of titanium oxide particles before the treatment. It is preferable to use and process.

  Hereinafter, a surface treatment method for producing titanium oxide particles that are surface-coated with a silane compound having a radically polymerizable functional group that is uniform and more finely described will be described.

  That is, a slurry (a suspension of solid particles) containing titanium oxide particles and a surface treatment agent of a silane compound having a radical polymerizable functional group is wet-pulverized to simultaneously refine the titanium oxide particles and Surface treatment proceeds. Thereafter, since the solvent is removed to form powder, titanium oxide particles that are surface-treated with a uniform and finer silane compound can be obtained.

  The wet media dispersion type apparatus, which is a surface treatment apparatus used in the present invention, is a metal oxide particle by filling beads in a container as a medium and rotating a stirring disk mounted perpendicularly to a rotation axis at high speed. It is a device having a step of crushing and pulverizing and dispersing the aggregated particles of the metal oxide, and the constitution thereof should be a type in which the metal oxide particles can be sufficiently dispersed and surface-treated when the surface treatment is performed on the metal oxide particles. For example, various types such as a vertical type, a horizontal type, a continuous type, and a batch type can be adopted. Specifically, a sand mill, ultra visco mill, pearl mill, glen mill, dyno mill, agitator mill, dynamic mill and the like can be used. These dispersion-type devices are pulverized and dispersed by impact crushing, friction, cutting, shear stress or the like using a grinding medium (media) such as balls or beads.

  As the beads used in the wet media dispersion type apparatus, balls made of glass, alumina, zircon, zirconia, steel, flint stone or the like can be used, but those made of zirconia or zircon are particularly preferable. Further, as the size of the beads, those having a diameter of about 1 to 2 mm are usually used, but in the present invention, those having a diameter of about 0.1 to 1.0 mm are preferably used.

  Various materials such as stainless steel, nylon, and ceramic can be used for the disk and container inner wall used in the wet media dispersion type apparatus. In the present invention, the disk and container inner wall made of ceramic such as zirconia or silicon carbide are particularly used. Is preferred.

  Titanium oxide particles surface-treated with a surface treatment agent can be obtained by the wet treatment as described above.

  As described above, titanium oxide particles have been described, but metal oxide particles such as alumina, zinc oxide, tin oxide, and silica also have a hydroxyl group on the surface in the same manner as titanium oxide. Metal oxide particles surface-treated with an agent can be obtained.

(Polymerizable compound)
The protective layer according to the present invention contains a resin component obtained by polymerizing a polymerizable compound.

  The polymerizable compound is preferably a monomer that is polymerized (cured) by irradiation with active rays such as ultraviolet rays and electron beams and becomes a resin generally used as a binder resin for a photoreceptor, such as polystyrene or polyacrylate. In particular, styrene monomers, acrylic monomers, methacrylic monomers, vinyl toluene monomers, vinyl acetate monomers, and N-vinyl pyrrolidone monomers are preferable.

Among these, a radical polymerizable compound having an acryloyl group (CH ₂ ═CHCO—) or a methacryloyl group (CH ₂ ═CCH ₃ CO—) is particularly preferable because a curing reaction can be performed with a small amount of light or a short time.

  In the present invention, these radically polymerizable compounds may be used alone or in combination. In addition, these polymerizable compounds may use monomers, but may be used after oligomerization.

  Examples of radically polymerizable compounds are shown below.

  Here, R represents the following acryloyl group, and R ′ represents the following methacryloyl group.

  The radical polymerizable compound is preferably a compound having 3 or more functional groups (reactive groups). Further, the radical polymerizable compound may be used in combination of two or more kinds of compounds, but even in this case, it is preferable to use 50% by mass or more of the radical polymerizable compound having 3 or more functional groups. Further, the curable functional group equivalent, ie, “molecular weight / number of functional groups of polymerizable compound” is preferably 1000 or less, and more preferably 500 or less. This increases the crosslink density and improves wear resistance.

(Polymerization initiator)
When reacting the radical polymerizable compound used in the present invention, a method of reacting by electron beam cleavage, a method of reacting with light or heat by adding a radical polymerization initiator, and the like are used. As the polymerization initiator, either a photopolymerization initiator or a thermal polymerization initiator can be used. In addition, both light and heat initiators can be used in combination.

  Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 (“Irgacure 369” manufactured by BASF Japan Ltd.), 2-hydroxy-2 -Methyl-1-phenylpropan-1-one, 2-methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) Acetophenone-based or ketal-based photopolymerization initiators such as oximes; benzoin, benzoin methyl ether Benzoin ether photopolymerization initiators such as benzoin ethyl ether, benzoin isobutyl ether, and benzoin isopropyl ether; benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4- Benzophenone-based photopolymerization initiators such as benzoylphenyl ether, acrylated benzophenone, and 1,4-benzoylbenzene; 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, and 2 Thioxanthone-based photopolymerization initiators such as 1,4-dichlorothioxanthone.

  Examples of other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, and bis (2,4,6-trimethylbenzoyl). Phenylphosphine oxide (“Irgacure 819” manufactured by BASF Japan Ltd.), bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10-phenanthrene, acridine Compounds, triazine compounds, and imidazole compounds. In addition, a photopolymerization accelerator having a photopolymerization promoting effect can be used alone or in combination with the photopolymerization initiator. Examples of the photopolymerization accelerator include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, and 4,4′-dimethylamino. Examples include benzophenone.

  On the other hand, as the thermal polymerization initiator, ketone peroxide compounds, peroxyketal compounds, hydroperoxide compounds, dialkyl peroxide compounds, diacyl peroxide compounds, peroxydicarbonate compounds, or peroxy esters These thermal polymerization initiators are published in company product catalogs and the like.

  The polymerization initiator used in the present invention is preferably a photopolymerization initiator, preferably an alkylphenone compound and a phosphine oxide compound, more preferably an initiator having an α-hydroxyacetophenone structure or an acylphosphine oxide structure. Is preferred.

  These polymerization initiators may be used alone or in combination of two or more. Content of a polymerization initiator is 0.1-20 mass parts with respect to 100 mass parts of an acryl-type compound, Preferably it exists in the range of 0.5-10 mass parts.

(Method for forming protective layer)
The protective layer according to the present invention is a composition in which the compound represented by the general formula (1), the metal oxide particles, the polymerizable compound, the polymerization initiator and the like are mixed in a solvent, and the composition is described later. After coating on the charge transporting layer, it can be dried and polymerized to form a protective layer which is a resin layer.

  In the process of coating, drying and curing, the reaction between the radical polymerizable functional groups of the surface-treated metal oxide particles, the reaction between the radical polymerizable functional group and the polymerizable compound, the reaction between the polymerizable compounds, etc. The protective layer of the cured resin layer is formed by mixing and proceeding.

  The ratio of the metal oxide particles in the protective layer is preferably 30 to 150 parts by mass, and more preferably 50 to 100 parts by mass when the resin component of the protective layer is 100 parts by mass.

  Each mass% can be verified from the mass of the protective layer, the mass detected by decomposing the resin layer of the protective layer and taking out the metal oxide particles.

  The proportion of the compound of the general formula (1) in the protective layer is preferably 10 to 50 parts by mass, preferably 10 to 35 parts by mass of the compound of the general formula (1) when the resin component of the protective layer is 100 parts by mass. Part is more preferred.

  The proportion of the compound of the general formula (1) in the protective layer can be verified by decomposing the protective layer and measuring the mass of the resin component and the compound of the general formula (1) in the protective layer.

  The proportion of the compound of the general formula (1) in the protective layer can be predicted in advance from the amount of the coating liquid component such as the polymerizable compound in the protective layer coating liquid.

  Thus, the curable protective layer according to the present invention is represented by the general formula (1) containing 0.05% by mass or less of the compound represented by the general formula (2) or the general formula (3). By containing such a charge transport material, trapping of charge carriers in the protective layer can be prevented, and an increase in residual potential and image memory (transfer memory) can be prevented.

  Further, the protective layer according to the present invention can further contain various antioxidants, and various lubricant particles can be added. For example, fluorine atom-containing resin particles can be added. Fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluorochloroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin, and these One or two or more types are preferably selected from the copolymers, but tetrafluoroethylene resin and vinylidene fluoride resin are particularly preferable.

  Solvents for forming the protective layer include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol, benzyl alcohol, toluene, xylene, methylene chloride, methyl ethyl ketone, cyclohexane, acetic acid. Examples thereof include, but are not limited to, ethyl, butyl acetate, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine and diethylamine.

  The protective layer according to the present invention is preferably reacted by irradiating actinic rays after natural drying or heat drying after coating.

  The coating method is the same as the photosensitive layer, such as dip coating method, spray coating method, spinner coating method, bead coating method, blade coating method, beam coating method, and slide hopper method (quantity-regulated coating method). Can be used.

  The photoreceptor of the present invention is capable of generating a cured resin by irradiating actinic rays on the coating to generate radicals and polymerizing, and curing by forming a cross-linking bond between molecules and within the molecule. preferable. As the active ray, ultraviolet rays and electron beams are particularly preferable.

As the ultraviolet light source, any light source that generates ultraviolet light can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a flash (pulse) xenon, or the like can be used. Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually 5 to 500 mJ / cm ² , preferably 5 to 100 mJ / cm ² . The power of the lamp is preferably 0.1 kW to 5 kW, particularly preferably 0.5 kW to 3 kW.

  As an electron beam source, there is no particular limitation on the electron beam irradiation apparatus, and generally, an electron beam accelerator for electron beam irradiation is a curtain beam type that is relatively inexpensive and can provide a large output. Used. The acceleration voltage during electron beam irradiation is preferably 100 to 300 kV. The absorbed dose is preferably 0.5 to 10 Mrad.

  The irradiation time for obtaining the necessary irradiation amount of active rays is preferably 0.1 second to 10 minutes, and more preferably 0.1 second to 5 minutes from the viewpoint of work efficiency.

  As the actinic radiation, ultraviolet rays are easy to use and are particularly preferable.

  The photoreceptor of the present invention can be dried before and after irradiating active rays and during irradiation with active rays, and the timing of drying can be appropriately selected by combining them.

  Drying conditions can be appropriately selected depending on the type of solvent, film thickness, and the like. The drying temperature is preferably room temperature to 180 ° C, particularly preferably 80 to 140 ° C. The drying time is preferably 1 to 200 minutes, particularly preferably 5 to 100 minutes.

  The thickness of the protective layer is preferably 0.2 to 10 μm, more preferably 0.5 to 6 μm.

[Configuration of electrophotographic photoreceptor]
The configuration of the electrophotographic photosensitive member other than the protective layer is described below.

  In the present invention, the electrophotographic photosensitive member means an electrophotographic photosensitive member constituted by giving an organic compound at least one of a charge generating function and a charge transporting function essential to the constitution of the electrophotographic photosensitive member, It contains all known electrophotographic photoreceptors such as a photoreceptor composed of a known organic charge generating material or organic charge transport material, a photoreceptor composed of a polymer complex with a charge generating function and a charge transport function.

  The electrophotographic photoreceptor of the present invention has a layer structure in which a charge generation layer, a charge transport layer, and a protective layer are sequentially laminated as a photosensitive layer on a conductive support. Moreover, it is preferable to have an intermediate | middle layer between an electroconductive support body and a charge generation layer.

  The layer structure of the electrophotographic photosensitive member of the present invention will be described focusing on the above.

(Conductive support)
The support used in the present invention may be any one as long as it has conductivity, for example, a metal such as aluminum, copper, chromium, nickel, zinc and stainless steel formed into a drum or sheet, aluminum or copper Metal foils such as those laminated on plastic films, aluminum, indium oxide and tin oxide deposited on plastic films, conductive materials alone or with a binder resin and a conductive layer provided, plastic films and For example, paper.

(Middle layer)
In the present invention, an intermediate layer having a barrier function and an adhesive function may be provided between the conductive layer and the photosensitive layer. Considering various types of failure prevention, it can be said that providing an intermediate layer is a preferable mode.

  The intermediate layer can be formed by dip coating or the like by dissolving a binder resin such as casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide, polyurethane and gelatin in a known solvent. Of these, an alcohol-soluble polyamide resin is preferred.

  Various conductive fine particles and metal oxide particles can be contained for the purpose of adjusting the resistance of the intermediate layer. For example, various metal oxide particles such as alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, and bismuth oxide. Ultrafine particles such as indium oxide doped with tin, tin oxide doped with antimony, and zirconium oxide can be used.

  These metal oxide particles may be used alone or in combination. When two or more types are mixed, they may take the form of a solid solution or fusion. The average particle size of such metal oxide particles is preferably 0.3 μm or less, more preferably 0.1 μm or less.

  As the solvent used for the intermediate layer, a solvent in which inorganic particles are well dispersed and the polyamide resin is dissolved is preferable. Specifically, alcohols having 2 to 4 carbon atoms such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol and the like are excellent in solubility and coating performance of the polyamide resin. In addition, examples of co-solvents that can be used in combination with the above-described solvent to obtain favorable effects in order to improve storage stability and particle dispersibility include methanol, benzyl alcohol, toluene, methylene chloride, cyclohexanone, and tetrahydrofuran.

  The density | concentration of binder resin is suitably selected according to the film thickness and production rate of an intermediate | middle layer.

  When the inorganic particles are dispersed, the mixing ratio of the inorganic particles to the binder resin at the time is preferably 20 to 400 parts by mass, more preferably 50 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  As a means for dispersing the inorganic particles, an ultrasonic disperser, a ball mill, a sand grinder, a homomixer, or the like can be used, but is not limited thereto.

  The method for drying the intermediate layer can be appropriately selected according to the type of solvent and the film thickness, but thermal drying is preferred.

  The thickness of the intermediate layer is preferably from 0.1 to 15 μm, more preferably from 0.3 to 10 μm.

(Charge generation layer)
The charge generation layer is a layer that absorbs light and generates charges. The charge generation layer used in the present invention contains a charge generation material and a binder resin, and the charge generation material is dispersed and applied in a binder resin solution. It is preferable to form them.

  The charge generation material is a material that absorbs light to generate charge, azo raw materials such as Sudan Red and Diane Blue, quinone pigments such as pyrenequinone and anthanthrone, quinocyanine pigments, perylene pigments, indigo pigments such as indigo and thioindigo, Examples thereof include, but are not limited to, polycyclic quinone pigments such as pyranthrone and diphthaloylpyrene, and phthalocyanine pigments. These charge generating materials can be used alone or in a form dispersed in a known resin.

  As the binder resin of the charge generation layer, a known resin can be used, for example, polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, Polyurethane resins, phenol resins, polyester resins, alkyd resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of these resins (eg, vinyl chloride-vinyl acetate copolymer resins, chlorides) Vinyl-vinyl acetate-maleic anhydride copolymer resin) and poly-vinylcarbazole resin, but are not limited thereto.

  The charge generation layer is formed by dispersing a charge generation material in a solution in which a binder resin is dissolved in a solvent using a disperser to prepare a coating solution, and applying the coating solution to a certain film thickness using a coating device. It is preferable to prepare the film by drying.

  Solvents for dissolving and coating the binder resin used in the charge generation layer include, for example, toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methanol, ethanol, propanol, Examples include butanol, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine, and diethylamine, but are not limited thereto.

  As a means for dispersing the charge generating material, an ultrasonic disperser, a ball mill, a sand grinder, a homomixer, or the like can be used, but is not limited thereto.

  The mixing ratio of the charge generating material to the binder resin is preferably 1 to 600 parts by weight, more preferably 50 to 500 parts by weight based on 100 parts by weight of the binder resin. The thickness of the charge generation layer varies depending on the characteristics of the charge generation material, the characteristics of the binder resin, the mixing ratio, and the like, but is preferably 0.01 to 5 μm, more preferably 0.05 to 3 μm. It should be noted that the coating solution for the charge generation layer can prevent the occurrence of image defects by filtering foreign matter and aggregates before coating. The charge generation layer can also be formed by vacuum deposition of the pigment.

(Charge transport layer)
The charge transport layer transports charges generated in the charge generation layer. The charge transport layer used in the photoreceptor of the present invention contains a charge transport material (CTM) and a binder resin, and the charge transport material is used as a binder resin solution. It is formed by dissolving and coating inside.

  Generally, in a negatively charged electrophotographic photosensitive member, a hole transporting charge transport material is used. As such a charge transport material, a known compound can be used, and examples thereof include the following compounds. Carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, pyrazoline compounds, oxazolone derivatives, benz Imidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, benzidine derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene and poly-9 -Vinylanthracene and the like. These compounds can be used alone or in admixture of two or more.

  A known resin can be used as the binder resin for the charge transport layer, and polycarbonate resin, polyacrylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polymethacrylic ester resin, and styrene-methacrylic acid. Examples include ester copolymer resins, and polycarbonate is preferred. Furthermore, BPA, BPZ, dimethyl BPA, BPA-dimethyl BPA copolymer, etc. are preferable in terms of crack resistance, wear resistance, and charging characteristics.

  The charge transport layer is preferably formed by dissolving the binder resin and the charge transport material to prepare a coating solution, applying the coating solution to a certain film thickness with a coating machine, and drying the coating film.

  Examples of the solvent for dissolving the binder resin and the charge transport material include toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, and tetrahydrofuran. 1,4-dioxane, 1,3-dioxolane, pyridine, diethylamine, and the like, but are not limited thereto.

  The mixing ratio of the charge transport material to the binder resin is preferably 10 to 500 parts by mass, more preferably 20 to 100 parts by mass with respect to 100 parts by mass of the binder resin.

  The thickness of the charge transport layer varies depending on the characteristics of the charge transport material, the characteristics of the binder resin, the mixing ratio, and the like, but is preferably 5 to 40 μm, and more preferably 10 to 30 μm.

  An antioxidant, an electronic conductive agent, a stabilizer and the like may be added to the charge transport layer. As the antioxidant, those described in JP-A No. 2000-305291 and the electronic conductive agent as described in JP-A Nos. 50-137543 and 58-76483 are preferable.

  Next, an image forming apparatus provided with the electrophotographic photosensitive member of the present invention will be described.

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

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

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

  The four sets of image forming units 10Y, 10M, 10C, and 10Bk are centered around the photosensitive drum 1Y, 1M, 1C, or 1Bk, and charging means 2Y, 2M, 2C, or 2Bk, and image exposure means 3Y, 3M. 3C, 3Bk, rotating developing means 4Y, 4M, 4C, or 4Bk, and cleaning means 6Y, 6M, 6C, or 6Bk for cleaning the photosensitive drums 1Y, 1M, 1C, or 1Bk. Yes.

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

  The image forming unit 10Y includes a charging unit 2Y (hereinafter simply referred to as a charging unit 2Y or a charger 2Y), an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 6Y around a photosensitive drum 1Y that is an image forming body. (Hereinafter simply referred to as the cleaning means 6Y or the cleaning blade 6Y) is arranged to form a yellow (Y) toner image on the photosensitive drum 1Y. In the present embodiment, in the image forming unit 10Y, at least the photosensitive drum 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 6Y are provided so as to be integrated.

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

  The image exposure means 3Y performs exposure based on the image signal (yellow) on the photosensitive drum 1Y given a uniform potential by the charger 2Y, and forms an electrostatic latent image corresponding to the yellow image. As the exposure unit 3Y, a unit composed of LEDs and light-emitting elements in which light emitting elements are arranged in an array in the axial direction of the photosensitive drum 1Y, a laser optical system, or the like is used.

  The image forming apparatus of the present invention is configured by integrally combining the above-described photosensitive member, developing unit, cleaning unit, and the like as a process cartridge (image forming unit). On the other hand, it may be configured to be detachable. A process cartridge (image forming unit) 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 is detachable from the apparatus main body. A single image forming unit may be detachable using guide means such as a rail of the apparatus main body.

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

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10Bk is transferred onto a rotating endless belt-shaped intermediate transfer body 70 by primary transfer rollers 5Y, 5M, 5C, and 5Bk as primary transfer means. The images are sequentially transferred to form a synthesized color image. An image support P as a transfer material (an image support that carries a fixed final image: for example, plain paper, a transparent sheet, etc.) housed in the paper feed cassette 20 is fed by a paper feed transport unit 21, A plurality of intermediate rollers 22A, 22B, 22C, 22D and a registration roller 23 are conveyed to a secondary transfer roller 5b as a secondary transfer means, and are secondarily transferred onto an image support P to collectively transfer color images. Is done. The image support P to which the color image has been transferred is subjected to fixing processing by the fixing means 24, is sandwiched between the paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus. Here, a transfer support for a toner image formed on a photosensitive member such as an intermediate transfer member or an image support is collectively referred to as a transfer medium.

  On the other hand, the endless belt-shaped intermediate transfer body 70 obtained by transferring the color image to the image support P by the secondary transfer roller 5b as the secondary transfer means and then separating the curvature of the image support P is subjected to residual toner by the cleaning means 6b. Removed.

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

  The secondary transfer roller 5b contacts the endless belt-shaped intermediate transfer body 70 only when the image support P passes through the secondary transfer roller 5b and the secondary transfer is performed.

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

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

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

  Although the color laser printer is shown in the image forming apparatus of FIG. 1, it is of course applicable to a monochrome laser printer and a copy as well. The exposure light source may also be a light source other than a laser, such as an LED light source.

  Next, the present invention will be described in detail while showing an actual configuration and its effects. However, of course, the embodiments of the present invention are not limited to these.

[Preparation of surface-treated metal oxide particles]
(Preparation of surface-treated metal oxide particles 1)
As the metal oxide particles, tin oxide A (manufactured by CIK Nanotech Co., Ltd.) having a number average primary particle diameter of 20 nm and a volume resistivity of 1.05 × 10 ⁵ Ω · cm is used, and an exemplary compound having a radical polymerizable functional group ( S-15) was used to prepare a surface treatment with a compound having a radical polymerizable functional group as shown below.

  First, a mixed solution of 100 parts by mass of tin oxide A, 30 parts by mass of the exemplified compound (S-15) as a surface treatment agent, and 300 parts by mass of a mixed solvent of toluene / isopropyl alcohol = 1/1 (mass ratio) together with zirconia beads. The mixture was stirred in a sand mill at about 40 ° C. and a rotation speed of 1500 rpm, and surface treatment with a compound having a radical polymerizable functional group was performed. Further, the above treatment mixture is taken out, put into a Henschel mixer, stirred for 15 minutes at a rotational speed of 1500 rpm, and then dried at 120 ° C. for 3 hours to complete the surface treatment of tin oxide with the compound having a radical polymerizable functional group. As a result, surface-treated metal oxide particles 1 (surface-treated tin oxide A) were obtained. The surface of the tin oxide A particles was coated with the compound of S-15 by the surface treatment with the compound having the radical polymerizable functional group.

(Preparation of surface-treated metal oxide particles 2 to 4)
The metal oxide particles and the surface treatment agent were changed as shown in Table 1, and surface treated metal oxide particles 2 to 4 were produced in the same manner as the surface treated metal oxide particles 1.

酸化スズＡ：ＣＩＫナノテック社製
酸化スズＢ：テイカ社製
酸化チタンＡ：テイカ社製
酸化亜鉛Ａ：ＣＩＫナノテック社製

Tin oxide A: manufactured by CIK Nanotech Co., Ltd. tin oxide B: manufactured by Teika Co., Ltd. titanium oxide A: manufactured by Teika Co., Ltd. zinc oxide A: manufactured by CIK Nanotech Co., Ltd.

[Synthesis of protective layer CTM]
(Synthesis Example 1)
Under a nitrogen stream, put 0.52 g (2.7 mmol) of cuprous iodide, 1.08 g (5.5 mmol) of 1,10-phenanthroline monohydrate, and 10 ml of xylene in a four-headed flask equipped with a condenser. And stirred at 60 ° C. for 30 minutes. Next, 5.00 g (27.3 mmol) of 4-methyldiphenylamine, 9.01 g (32.8 mmol) of 4-iodo-4′-n-propylbiphenyl, 3.28 g (34.1 mmol) of sodium tert-butoxide, xylene 20 ml was added and refluxed at 130 ° C. for 6 hours. After allowing to cool, 100 ml of water was added and stirred for 30 minutes, and the organic layer was washed with water until the aqueous layer became neutral. After drying the organic layer with sodium sulfate, toluene was distilled off.

  The resulting crude product was purified using a silica gel column (developing solvent: n-heptane / toluene = 1/1) to obtain 7.52 g (yield 73%) of exemplary compound (CTM-13).

  The purity was calculated from the area value of high performance liquid chromatography.

  High performance liquid chromatography was measured under the following conditions.

Column: Shim-pack CLC-Phenyl (manufactured by Shimadzu Corporation)
Developing solvent: methanol / THF / water = 5/3/2
Flow rate: 1 ml / min
Detection wavelength: 290 nm
The retention time of the main component was 9.5 minutes, and the purity was 98.83% (area value). Further, when the impurity component having a retention time of 18.5 minutes was further separated by a silica gel column (developing solvent: n-heptane / toluene = 4/1) and subjected to structural analysis, the mass spectrum and NMR showed that p- It was a phenylenediamine compound (F-1). Content of (F-1) calculated | required from the analytical curve method by a high performance liquid chromatography was 0.15 mass% with respect to CTM-13.

  CTM-13 containing 0.15% by mass of the following p-phenylenediamine compound (F-1) as an impurity was designated as CT-1.

(Synthesis Example 2)
In the same manner as in Synthesis Example 1, the obtained crude product was purified by distillation (bp 250 ° C./13.3 Pa (0.1 Torr)) and then a silica gel column (developing solvent: n-heptane / toluene = 1). / 1) to obtain 7.12 g (yield 69%) of exemplary compound (CTM-13).

  The purity was 99.81% (area value), and the content of the p-phenylenediamine compound (F-1) was 0.04%. CTM-13 containing 0.04% by mass of this p-phenylenediamine compound (F-1) was designated as CT-2.

(Synthesis Example 3)
Under a nitrogen stream, 0.37 g (1.6 mmol) of palladium acetate and 1.33 g (6.6 mmol) of tri-tert-butylphosphine were placed in a four-headed flask equipped with a condenser and stirred at room temperature for 30 minutes. Next, 9.01 g (32.8 mmol) of 4-methyldiphenylamine, 4.96 g (22 mmol) of 4-bromo-4′-n-propylbiphenyl and 20 ml of toluene, 6.29 g (65.5 mmol) of sodium-tert-butoxide Was added and refluxed for 2 hours. After allowing to cool, 100 ml of water was added and stirred for 10 minutes, and the organic layer was washed with water until the aqueous layer became neutral. After drying the organic layer with sodium sulfate, toluene was distilled off.

  The obtained crude product was purified using a silica gel column (developing solvent: n-heptane / toluene = 1/1) to obtain 8.57 g (yield 83.2%) of the exemplified compound (CTM-13). It was.

  The purity was 99.52% (area value), and the content of the p-phenylenediamine compound (F-1) was 0.07%. CTM-13 containing 0.07% by mass of this p-phenylenediamine compound (F-1) was designated as CT-3.

(Synthesis Example 4)
The crude product obtained in the same manner as in Synthesis Example 3 was purified using a silica gel column (developing solvent: n-heptane / toluene = 4/1), and 7.96 g (yield 77%) of the exemplified compound (CTM -13) was obtained.

  The purity was 99.94% (area value), and the content of the p-phenylenediamine compound (F-1) was 0.01%. CTM-13 containing 0.01% by mass of this p-phenylenediamine compound (F-1) was designated as CT-4.

(Synthesis Example 5)
Exemplified compound (CTM-13) was synthesized in the same manner as in Synthetic Example 3, except that N-phenyl-4'-propylbiphenylamine was used as the amine compound and 4-bromotoluene was used as the aryl halide.

  The purity was 99.52% (area value), and a p-phenylenediamine compound (F-2) having the following structure was detected (content 0.09%). CTM-13 containing 0.07% by mass of this p-phenylenediamine compound (F-2) was designated CT-5.

（合成例６）
合成例５と同様にして得られた粗生成物を、シリカゲルカラム（展開溶媒：ｎ−ヘプタン／トルエン＝４／１）を用いて精製し、例示化合物（ＣＴＭ−１３）を得た。

(Synthesis Example 6)
The crude product obtained in the same manner as in Synthesis Example 5 was purified using a silica gel column (developing solvent: n-heptane / toluene = 4/1) to obtain an exemplary compound (CTM-13).

  The purity was 99.94% (area value), and the content of the p-phenylenediamine compound (F-2) was 0.02%. CTM-13 containing 0.01% by mass of this p-phenylenediamine compound (F-2) was designated as CT-6.

(Synthesis Examples 7 to 12)
Charge transport materials having different impurity contents in the same manner as in Synthesis Example 3 except that the amine compounds and aryl halides shown in Tables 2 and 3 were used and purified by the methods shown in Tables 2 and 3. CTM-2, 6 and 10) were synthesized respectively. These were designated as CT-7 to CT-12 in this order.

〔感光体の作製〕
（感光体１の作製）
下記のように感光体１を作製した。

[Production of photoconductor]
(Preparation of photoreceptor 1)
Photoreceptor 1 was produced as follows.

  The surface of a cylindrical aluminum support having a diameter of 60 mm was cut to prepare a conductive support having a fine and rough surface.

<Intermediate layer>
A dispersion having the following composition was diluted twice with the same mixed solvent, and allowed to stand overnight, followed by filtration (filter; using a lime mesh 5 μm filter manufactured by Nihon Pall) to prepare an intermediate layer coating solution.

Polyamide resin CM8000 (manufactured by Toray Industries, Inc.) 1 part by mass Titanium oxide SMT500SAS (manufactured by Teica) 3 parts by mass Methanol 10 parts by mass Using a sand mill as a disperser, dispersion was carried out for 10 hours in a batch system.

  It apply | coated by the dip coating method so that it might become a dry film thickness of 2 micrometers on the said support body using the said coating liquid.

<Charge generation layer>
Charge generation material: 24 parts by mass of the following pigment (CG-1) Polyvinyl butyral resin “ESREC BL-1” (manufactured by Sekisui Chemical Co., Ltd.) 12 parts by mass 3-methyl-2-butanone / cyclohexanone = 4/1 (V / V) 400 parts by mass The above components were mixed and dispersed using a circulating ultrasonic homogenizer RUS-600TCVP (manufactured by Nippon Seiki Seisakusho, 19.5 kHz, 600 W) at a circulating flow rate of 40 L / H for 0.5 hour and 10 hours. A generation layer coating solution was prepared. This coating solution was applied onto the intermediate layer by a dip coating method to form a charge generation layer having a dry film thickness of 0.3 μm.

  The charge generation material CG-1 was synthesized as follows.

(Synthesis of Pigment (CG-1))
(1) Synthesis of amorphous titanyl phthalocyanine 1,3-diiminoisoindoline; 29.2 parts by mass are dispersed in 200 parts by mass of o-dichlorobenzene, and titanium tetra-n-butoxide; 20.4 parts by mass are added. It heated at 150-160 degreeC for 5 hours under nitrogen atmosphere. After allowing to cool, the precipitated crystals were filtered, washed with chloroform, washed with 2% aqueous hydrochloric acid, washed with water, washed with methanol, and dried to obtain 26.2 parts by mass (yield 91%) of crude titanyl phthalocyanine.

  Next, crude titanyl phthalocyanine was dissolved by stirring for 1 hour in 250 parts by mass of concentrated sulfuric acid at 5 ° C. or less, and this was poured into 5000 parts by mass of water at 20 ° C. The precipitated crystals were filtered and sufficiently washed with water to obtain 225 parts by mass of a wet paste product.

  Next, the wet paste product was frozen in a freezer, thawed again, filtered and dried to obtain 24.8 parts by mass of amorphous titanyl phthalocyanine (yield 86%).

(2) Synthesis of (2R, 3R) -2,3-butanediol adduct titanyl phthalocyanine (CG-1) 10.0 parts by mass of the above-mentioned amorphous titanyl phthalocyanine and (2R, 3R) -2,3-butanediol 0.94 parts by mass (0.6 equivalent ratio) (equivalent ratio is equivalent to titanyl phthalocyanine, the same applies hereinafter) is mixed with 200 parts by mass of orthodichlorobenzene (ODB) and stirred at 60 to 70 ° C. for 6.0 hours. did. After standing overnight, methanol was added to the reaction solution, and the resulting crystals were filtered. The crystals after filtration were washed with methanol (a pigment containing (2R, 3R) -2,3-butanediol adduct titanyl phthalocyanine). CG-1: 10.3 mass parts was obtained. In the X-ray diffraction spectrum of CG-1, there are clear peaks at 8.3 °, 24.7 °, 25.1 °, and 26.5 °. There is a peak in the 576 and 648 in the mass spectra, O-Ti-O both absorption appears Ti = O near 970 cm ^-1, around 630 cm ^-1 in the IR spectrum. In addition, since thermal analysis (TG) has a mass loss of about 7% at 390 to 410 ° C., a 1: 1 adduct and a non-adduct (addition) of titanyl phthalocyanine and (2R, 3R) -2,3-butanediol It is presumed to be a mixed crystal of titanyl phthalocyanine.

It was 31.2 m < ² > / g when the BET specific surface area of the obtained CG-1 was measured with the flow type specific surface area automatic measuring device (Micrometrics flow soap type: Shimadzu Corporation).

この塗布液を前記電荷発生層の上に円形スライドホッパー塗布機（円形量規制型塗布機）を用いて塗布し、乾燥膜厚２０μｍの電荷輸送層を形成した。 <Charge transport layer>
Charge transport material (compound A below) 225 parts by weight Binder: Polycarbonate Z (Z300: manufactured by Mitsubishi Gas Chemical Company) 300 parts by weight Antioxidant (Irganox 1010: manufactured by BASF Japan) 6 parts by weight THF (tetrahydrofuran) 1600 parts by weight Toluene 400 Part by mass Silicone oil (KF-50: manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by mass was mixed and dissolved to prepare a charge transport layer coating solution.

This coating solution was applied onto the charge generation layer using a circular slide hopper coating machine (circular amount regulation type coating machine) to form a charge transport layer having a dry film thickness of 20 μm.

<Protective layer>
Subsequently, a protective layer was formed by the following method.

Coating liquid composition of protective layer Surface-treated metal oxide particles 1 50 parts by weight Polymerizable compound (Exemplary compound (M1)) 100 parts by weight Charge transport material (CT-1) 15 parts by weight Polymerization initiator (“Irgacure 819”: BASF Japan Ltd.) 10 parts by weight chain transfer agent (2-mercaptobenzoxazole) 10 parts by weight 2-butanol 320 parts by weight tetrahydrofuran 80 parts by weight The above coating composition is mixed and stirred, sufficiently dissolved and dispersed, and coated with a protective layer. A liquid was prepared. A protective layer was applied using a circular slide hopper applicator on the photoreceptor on which the coating solution had been prepared up to the charge transport layer. After the coating, the photosensitive member 1 was produced by irradiating with an ultraviolet ray for 1 minute using a metal halide lamp to form a protective layer having a dry film thickness of 3.0 μm.

(Production of photoconductors 2 to 12)
In the production of the photoreceptor 1, the same applies to the protective layer except that the compound of general formula (1) (charge transport material), the surface-treated metal oxide particles, and the polymerizable compound were changed as shown in Table 4. Photoconductors 2 to 12 were produced.

<Evaluation>
Evaluation was performed by using “bizhub PRO C6501” manufactured by Konica Minolta Business Technologies, Inc. having the configuration of FIG. 1 as the evaluation machine, and mounting each photoconductor on the evaluation machine.

  An endurance test was performed in which a 300,000 double-sided continuous print of a character image with an image ratio of 6% was performed at 23 ° C and 50% RH in an A4 horizontal feed. Wear characteristics, residual potential and image memory were evaluated. Evaluation was performed according to the following indicators.

(Evaluation of wear resistance)
The film thickness of the photosensitive layer was measured before and after the durability test, and the film thickness was calculated and evaluated.

  The film thickness of the photosensitive layer is measured at 10 points at random on the uniform film thickness part (excluding the film thickness fluctuation part at the leading and trailing edges of the coating), and the average value is measured for the photosensitive layer. The film thickness. The film thickness measuring device is an eddy current film thickness measuring device EDDY560C (manufactured by HELMUT FISCHER GMBTE CO), and the difference in the photosensitive layer thickness before and after the actual shooting test is defined as the film thickness depletion amount. The amount of wear per 100 krot (100,000 revolutions) is shown in Table 5 as the α value.

(Potential retention)
After the endurance test, the photoreceptor was charged with a surface potential of −700 V, and immediately after that, the power was turned off and the potential holding ratio (%) of the photoreceptor after 5 seconds was measured.

Potential holding ratio (%) = (surface potential after 5 seconds / surface potential immediately after charging) × 100
The surface potential was measured by installing a surface potential meter at the position of the developing means of the evaluation machine.

A: Potential holding ratio 93% or more (good)
○: Potential holding ratio 89% or more and less than 93% (no problem in practical use)
X: Potential holding rate of less than 89% (problematic problems)
(Evaluation of residual potential)
Evaluation was made based on the magnitude of the potential fluctuation of the exposed portion potential in the durability test.

  Judgment criteria are as shown below.

  The initial charging potential was adjusted to 600 ± 50 V, and evaluation was performed based on the amount of change (ΔV) in the exposed portion potential after the initial and 300,000 sheets.

A: ΔV is less than 50V (good)
○: ΔV is 50 to 100 V (no problem in practical use)
×: ΔV is larger than 100V (practical problem)
(Evaluation of image memory)
After the endurance test, ten images of solid black and solid white mixed are printed continuously, and then a uniform halftone image is printed, and the solid black and solid white history appears in the halftone image. Judgment is based on whether (memory is generated) or not (memory is not generated).

○: No memory generated ×: Memory generated Evaluation results are summarized in Table 5.

表５の結果より、本願発明の構成を有し、保護層に含有される電荷輸送物質中に含まれる一般式（１）又は一般式（３）で表される不純物が、０．０５％以下の電荷輸送物質を用いた本発明内の感光体２、４、６、８、１０及び１２は各評価項目において良好な評価を獲得している。

From the results of Table 5, the impurity represented by the general formula (1) or the general formula (3) contained in the charge transport material contained in the protective layer having the configuration of the present invention is 0.05% or less. The photoreceptors 2, 4, 6, 8, 10 and 12 in the present invention using the above charge transport materials have obtained favorable evaluations in the respective evaluation items.

  On the other hand, the comparative photoconductor 1 outside the present invention in which the impurity represented by the general formula (1) or the general formula (3) contained in the charge transport material contained in the protective layer exceeds 0.05% by mass, 3, 5, 7, 9, and 11 indicate that there is a problem in any of the evaluation items of the potential holding ratio, the residual potential, or the image memory.

1Y, 1M, 1C, 1Bk photoconductor 2Y, 2M, 2C, 2Bk charging means 3Y, 3M, 3C, 3Bk exposure means 4Y, 4M, 4C, 4Bk developing means 10Y, 10M, 10C, 10Bk image forming unit 7 intermediate transfer member P Image support (transfer material)

Claims (7)

An electrophotographic photosensitive member in which a charge generation layer, a charge transport layer, and a protective layer containing at least a charge transport material are sequentially laminated on a conductive support, wherein the charge transport material is represented by the following general formula (1). The content of the compound represented by the following general formula (2) or the general formula (3) is 0 to 0.00 with respect to the compound represented by the general formula (1). An electrophotographic photosensitive member characterized by being in the range of 05 mass%.

(In General Formula (1), General Formula (2), and General Formula (3), R ₁ , R _2, and R ₃ each independently represent a hydrogen atom, an alkyl group, or an alkoxy group. 1 represents an integer of 1 to 5, and m represents an integer of 1 to 4. When l, m, and n are 2 or more, R ₁ , R _2, and R ₃ may be the same or different.   The electrophotographic photosensitive member according to claim 1, wherein the protective layer contains at least a resin component obtained by polymerizing a polymerizable compound and metal oxide particles.   3. The electrophotographic photoreceptor according to claim 2, wherein the metal oxide particles are surface-treated with a surface treatment agent having a methacryloyl group or an acryloyl group.   4. The electrophotographic photoreceptor according to claim 2, wherein the metal oxide particles are any one selected from tin oxide particles, titanium oxide particles, and zinc oxide particles.   The content of the compound represented by the general formula (1) in the protective layer is in the range of 10 to 50 parts by mass with respect to 100 parts by mass of the resin component obtained by polymerizing the polymerizable compound. The electrophotographic photosensitive member according to any one of claims 1 to 4, wherein the electrophotographic photosensitive member is characterized in that:   An electrophotographic image forming method using the electrophotographic photosensitive member according to any one of claims 1 to 5.   An electrophotographic image forming apparatus comprising the electrophotographic photosensitive member according to any one of claims 1 to 5.

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