JP2007121733A - Electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor in which cracks and crystallization of a photosensitive layer do not occur frequently due to adhesion of finger oil thereto. <P>SOLUTION: The electrophotographic photoreceptor has a single layer type or multilayer type photosensitive layer containing a hole transport agent and a binder resin on a conductive substrate, wherein a first polycarbonate resin and a second polycarbonate resin having mutually different molecular structures are contained as the binder resin, and the photosensitive layer contains a triphenylamine compound represented by formula (1) as an additive. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member, and more particularly to an electrophotographic photosensitive member in which generation of cracks, crystallization of a photosensitive layer, and the like are less caused by adhesion of finger oil.

Conventionally, as an electrophotographic photosensitive member used in an image forming apparatus, a charge generating agent that generates a charge by light irradiation, a charge transporting agent that transports the generated charge, and a binder that constitutes a layer in which these substances are dispersed. Organic photoreceptors made of resins and the like are widely used.
In addition, the surface of such an organic photoreceptor is charged (main charging step) and an electrostatic latent image is formed (exposure step), and then the electrostatic latent image is applied with a developing bias voltage. An image forming process is performed in which toner development (development process) is performed, and the formed toner image is transferred to transfer paper by a reversal development method (transfer process), which is heated and fixed to form a predetermined image. ing.
The residual toner on the organic photoconductor is removed using a cleaning blade (cleaning step), and the residual charge on the organic photoconductor is erased by an LED or the like (static elimination step). .

However, the conventional electrophotographic photosensitive member has not only low sensitivity but also has a problem of poor durability.
Therefore, in the electrophotographic photosensitive member used in the reversal development method, an electrophotographic photosensitive member to which a high-sensitivity and a fluorene compound having a specific structure and a triphenylamine compound are added in order to suppress generation of cracks in the photosensitive layer is provided. It is disclosed (for example, Patent Document 1).
Patent 3155856 (Claims)

However, the electrophotographic photosensitive member disclosed in Patent Document 1 has not only poor durability and wear resistance, but also has a problem of insufficient sensitivity characteristics.
Further, the electrophotographic photosensitive member disclosed in Patent Document 1 has a new problem that cracks are easily generated due to adhesion of finger oil or the like, and a photosensitive layer is crystallized.

Thus, as a result of intensive studies, the inventors of the present invention have improved durability and wear resistance by using the first and second polycarbonate resins having different molecular structures and adding predetermined additives. In addition, the present inventors have found that the sensitivity characteristics are improved, and further, cracking and crystallization due to adhesion of finger oil or the like can be effectively prevented.
That is, the present invention provides an electrophotographic photosensitive member that is excellent in durability, abrasion resistance, and sensitivity characteristics, and is less likely to cause cracking or crystallization of the photosensitive layer due to finger oil adhesion. The purpose is to do.

According to the electrophotographic photoreceptor of the present invention, an electrophotographic photoreceptor comprising a single layer type or a laminated type photosensitive layer containing at least a hole transport agent and a binder resin on a conductive substrate. The binder resin includes a first polycarbonate resin and a second polycarbonate resin having different molecular structures, and the photosensitive layer contains a triphenylamine compound represented by the following general formula (1) as an additive. An electrophotographic photosensitive member is provided, which can solve the above-described problems.
That is, by configuring in this way, a plurality of polycarbonate resins as a binder resin and an additive having a specific structure can interact to improve durability and wear resistance as well as sensitivity. The characteristics are also improved, and furthermore, generation of cracks and crystallization due to adhesion of finger oil or the like can be effectively prevented.

(In the general formula (1), Ra, Rb, and Rc are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon number of 1 to 12 An alkoxy group, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, wherein the repeating numbers k, l and m are integers of 0 to 5. is there.)

Further, in constituting the electrophotographic photoreceptor of the present invention, the content of the additive is 0.1 to 15 parts by weight with respect to 100 parts by weight of the binder resin when the photosensitive layer is a single layer type. When the photosensitive layer is a laminate type, the value is preferably in the range of 1 to 30 parts by weight with respect to 100 parts by weight of the binder resin in the surface layer.
With this configuration, the interaction between the binder resin and the triphenylamine compound as an additive can be more effectively exhibited regardless of whether the photosensitive layer is a single layer type or a laminated type. Can do. Accordingly, not only the wear resistance and sensitivity characteristics are improved, but also the occurrence of cracks and crystallization due to adhesion of finger oil and the like can be further effectively prevented.

In constituting the electrophotographic photoreceptor of the present invention, the additive is preferably a compound represented by the following general formulas (2) to (5) or a derivative thereof.
By comprising in this way, interaction with binder resin and an additive can be exhibited more effectively. Accordingly, not only the wear resistance and sensitivity characteristics are improved, but also the occurrence of cracks and crystallization due to adhesion of finger oil or the like can be more effectively prevented.

In constituting the electrophotographic photoreceptor of the present invention, the first polycarbonate resin includes a polycarbonate resin represented by the following general formula (6), and the second polycarbonate resin includes the following general formula (7) or (8). It is preferable that the polycarbonate resin shown by this is included.
By comprising in this way, the triphenylamine compound as an additive is selectively compatible with the polycarbonate resin of the molecular structure represented by Formula (7) or (8), and is represented by Formula (6). The polycarbonate resin having the molecular structure can provide mechanical strength, and the contradictory properties of finger oil resistance and wear resistance can be obtained at the same time.

(In the general formula (6), Rd and Re are each an independent hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, and the suffixes n and o are Each independently represents an integer of 0 to 4; Rf and Rg are a hydrogen atom or an alkyl group having 1 to 2 carbon atoms; W is a single bond or —O— or —CO—; Is a molar ratio that satisfies the relational expression of 0.05 <q / (q + p) <0.6.)

(In the general formula (7), a plurality of substituents Rh are a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. r is an integer of 0-4.)

(In the general formula (8), the plurality of substituents Ri are a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. s is an integer of 0-4.)

In constructing the electrophotographic photosensitive member of the present invention, the photosensitive layer has a 95% response time (at a wavelength of 780 nm corresponding to a charging voltage of 100 V after 300 msec after charging at a temperature of 23 ° C. and 700 V). Depending on the amount of exposure, it is preferable to set the charging time to 130V within 20 msec.
With this configuration, a predetermined sensitivity characteristic can be stably obtained.

In constituting the electrophotographic photosensitive member of the present invention, the glass transition point (DSC measurement) of the photosensitive layer is preferably set to a value of 65 ° C. or higher.
With this configuration, not only the wear resistance and sensitivity characteristics are stably improved, but also the occurrence of cracks and crystallization due to adhesion of finger oil or the like can be further effectively prevented.

In constituting the electrophotographic photosensitive member of the present invention, the hole transport agent is preferably a bisstilbene compound or a bisbutadiene compound.
With this configuration, not only the wear resistance and sensitivity characteristics are stably improved, but also the occurrence of cracks and crystallization due to adhesion of finger oil or the like can be further effectively prevented.

In constituting the electrophotographic photoreceptor of the present invention, it is preferable that the bisstilbene compound or bisbutadiene compound as the hole transporting agent has a symmetric structure.
By comprising in this way, the triphenylamine compound as an additive can be further selectively mixed with a polycarbonate resin having a specific molecular structure, and the wear resistance and sensitivity characteristics are stably improved. In addition, cracking and crystallization due to adhesion of finger oil or the like can be further effectively prevented.
Note that the bisstilbene compound or the bisbutadiene compound has a symmetric structure when each of the bisstilbene compound or the bisbutadiene compound is separated with reference to the reference carbon or the reference plane as in the compounds represented by formulas (13) to (16). It means that it is in a mirror symmetry state.

[First embodiment]
In the first embodiment of the present invention, as illustrated in FIG. 1, an electrophotographic photoreceptor including a laminated photosensitive layer containing at least a hole transport agent and a binder resin on a conductive substrate. An electrophotography comprising a first polycarbonate resin and a second carbonate resin having different molecular structures as binder resins, and the photosensitive layer containing a triphenylamine compound as an additive It is a photoreceptor.
Hereinafter, the multilayer electrophotographic photosensitive member according to the first embodiment of the present invention will be described in detail.

1. Support substrate As the support substrate 12 illustrated in FIG. 1, various materials having conductivity can be used. For example, iron, aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, Examples thereof include metals such as nickel, palladium, indium, stainless steel, and brass, plastic materials on which the above metals are deposited or laminated, glass coated with aluminum iodide, tin oxide, indium oxide, and the like.
Further, the shape of the support substrate may be any of a sheet shape, a drum shape, or the like in accordance with the structure of the image forming apparatus to be used. The substrate itself has conductivity or the surface of the substrate has conductivity. It only has to have. Further, it is preferable that the support substrate has sufficient mechanical strength when used.
In addition, in order to prevent the occurrence of interference fringes, the surface of the support substrate is roughened using methods such as etching, anodizing, wet blasting, sand blasting, rough cutting, and centerless cutting. May be.
In addition, when anodizing or the like is performed on the support base, there may be non-conductivity or semiconductor characteristics, but even in such a case, as long as a predetermined effect is obtained, Can be included.

2. Intermediate Layer (1) Basic Structure As illustrated in FIG. 1, an intermediate layer 25 containing a predetermined binder resin may be provided on the support base 12.

(2) Binder resin Binder resins used for the intermediate layer include thermoplastic resins such as polyvinyl alcohol, polyvinyl butyral, casein, sodium polyacrylate, copolymer nylon, methoxymethylated nylon, polyurethane, melamine, epoxy, Examples thereof include thermosetting resins such as alkyd, phenol, acrylic, and fluororesin.

(3) Additives In addition, in the range where sedimentation at the time of manufacture does not become a problem, for the purpose of preventing the generation of interference fringes by causing light scattering and improving dispersibility, etc. It is also preferable to add a small amount of an additive (organic fine powder or inorganic fine powder).
In particular, white pigments such as titanium oxide, zinc oxide, zinc white, zinc sulfide, lead white, lithopone, inorganic pigments such as alumina, calcium carbonate, barium sulfate, etc., fluorine resin particles, benzoguanamine resin particles, styrene resins Particles and the like are preferred additives.
Moreover, when adding additives, such as a fine powder, it is preferable to make the particle size into the value within the range of 0.01-3 micrometers. This is because if the particle size is too large, the unevenness of the intermediate layer may increase, an electrically non-uniform portion may occur, and image quality defects may easily occur. On the other hand, if the particle size is too small, a sufficient light scattering effect may not be obtained.
In addition, when adding additives, such as a fine powder, the addition amount is 1000 parts weight or less with respect to 100 weight part of resin of an intermediate | middle layer, 20-500 weight part is preferable, and it shall be 50-300 weight part. More preferred.

(4) Film thickness Moreover, since the concealability of the unevenness | corrugation in a support base material increases by making a film thickness thick, it is preferable in the direction which reduces a spot-like image quality defect, On the contrary, Electrical characteristics such as an increase in residual potential tend to decrease.
Therefore, the thickness of the intermediate layer is preferably set to a value within the range of 0.1 to 50 μm, and more preferably set to a value within the range of 0.5 to 30 μm.

3. Charge generation layer (1) Basic structure The charge generation layer is composed of 20 to 500 parts by weight of the charge generation material and 1,000 to 50,000 parts by weight of the organic solvent with respect to 100 parts by weight of the binder resin. Each of them is composed of a coating of a coating solution for a charge generation layer. That is, the charge generation layer is formed by spraying an organic solvent after applying a predetermined charge generation layer coating solution.
This is because the charge generation layer can be formed more uniformly and stably by forming the charge generation layer from the charge generation layer coating liquid having such a blending ratio. Therefore, the light potential under low temperature and low humidity conditions and the fog characteristics under high temperature and high humidity are improved, and can be formed stably and economically.
The film thickness of the charge generation layer is generally 0.01 to 5.0 μm, preferably 0.05 to 3.0 μm.

(2) Charge generator As the charge generator used in the electrophotographic photoreceptor of the present invention, for example, phthalocyanine pigments such as metal-free phthalocyanine and oxotitanyl phthalocyanine, perylene pigments, bisazo pigments, diketopyrrolopyrrole pigments , Metal-free naphthalocyanine pigment, metal naphthalocyanine pigment, squaraine pigment, trisazo pigment, indigo pigment, azulenium pigment, cyanine pigment, pyrylium pigment, ansanthrone pigment, triphenylmethane pigment, selenium pigment, toluidine pigment, pyrazoline pigment Conventionally known charge generating agents such as organic photoconductors such as pigments and quinacridone pigments and inorganic photoconductive materials such as selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, and amorphous silicon can be used.

  Of these charge generators, specifically, phthalocyanine pigments (CGM-A to CGM-D) represented by the following formulas (9) to (12) are more preferably used.

In addition, among the above-described charge generating agents, in particular, when used in a digital optical image forming apparatus such as a laser beam printer or a facsimile provided with a light source such as a semiconductor laser, sensitivity is improved in a wavelength region of 600 to 800 nm or more. Therefore, it is preferable that at least one of metal-free phthalocyanine, titanyl phthalocyanine, hydroxygallium phthalocyanine, and chlorogallium phthalocyanine is contained.
On the other hand, when used in an image forming apparatus of an analog optical system such as an electrostatic copying machine equipped with a white light source such as a halogen lamp, a photoreceptor having sensitivity in the visible region is required. Pigments and bisazo pigments are preferably used.
In the case of a single-layer type photoreceptor, the amount of charge generator added is preferably set to a value in the range of 0.1 to 50% by weight, based on the total weight of the binder resin, 0.5 to 30 More preferably, the value is within the range of% by weight.

(3) Binder Resin When the type of the binder resin constituting the charge generation layer corresponds to the surface layer, the first polycarbonate resin and the second polycarbonate resin having different molecular structures are used as the binder resin. 2 carbonate resin.
The reason for this is that by configuring in this way, the interaction between the binder resin and the triphenylamine compound as an additive can be more effectively exhibited. That is, the triphenylamine compound as an additive is selectively compatible with the second polycarbonate resin and maintains an incompatible state with the first polycarbonate resin, thereby improving mechanical strength and durability. While maintaining, it is possible to effectively prevent cracking and crystallization due to adhesion of finger oil or the like.
The details of the binder resin will be described in detail in the item of the charge transport layer described later.

(4) Additive The photosensitive layer contains a triphenylamine compound having a predetermined structure as an additive.
This is because by using such an additive, the interaction with the binder resin can be more effectively exhibited.
That is, if it is a triphenylamine compound as such an additive, cracking due to adhesion of finger oil or the like while maintaining mechanical strength and durability by being selectively compatible with the second polycarbonate resin And crystallization can be effectively prevented. The details of the triphenylamine compound as the additive will be described in detail in the item of the charge transport layer described later.

Moreover, it is preferable to make content of such an additive into the value within the range of 1-30 weight part with respect to 100 weight part of binder resin in a charge generation layer.
This is because, when the content of the additive is less than 1 part by weight, it may be difficult to selectively dissolve with the second polycarbonate resin. In addition, when the content of the additive exceeds 30 parts by weight, the selectivity is lowered, and the mechanical strength and durability may be significantly lowered.
Therefore, the content of the additive is more preferably set to a value in the range of 2 to 20 parts by weight, and a value in the range of 3 to 15 parts by weight with respect to 100 parts by weight of the binder resin in the charge generation layer. More preferably.

4). Charge Transport Layer (1) Basic Configuration The charge transport layer is preferably formed by uniformly dispersing together with a charge transport agent (hole transport agent), an organic solvent and a binder resin, and then applying.
Therefore, in preparing the charge transport layer, the blending ratio of the charge transport agent and the binder resin is preferably in the range of 10: 1 to 1: 5.
The thickness of the charge transport layer is generally set to a value in the range of 2 to 100 μm, preferably 5 to 50 μm.

(2) Hole transport agent (2) -1 type As the hole transport agent used in the charge transport layer of the present invention, various conventionally known compounds can be used. Specifically, benzidine compounds, phenylenediamine compounds, naphthylenediamine compounds, phenanthrylenediamine compounds, oxadiazole compounds, styryl compounds, carbazole compounds, pyrazoline compounds, hydrazone compounds, triphenyl Amine compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, triazole compounds, butadiene compounds, pyrene-hydrazone compounds, acrolein compounds Carbazole-hydrazone compound, quinoline-hydrazone compound, stilbene compound, stilbene-hydrazone compound, and diphenylenediamine compound alone or It includes the species or more combinations.

(2) -2 Specific Example 1
Specific examples of the hole transport agent include compounds represented by the following general formulas (13) to (16).

(In formula (13), R ^{1 to} R ¹² are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon number 1 to 1) 12 alkoxy groups, substituted or unsubstituted aryl groups having 6 to 30 carbon atoms, substituted or unsubstituted alkenyl groups having 6 to 30 carbon atoms, -OR ¹³ (R ¹³ is an alkyl group having 1 to 10 carbon atoms, Each of R ^{1 to} R ⁵ , R ^{6 to} R ¹⁰ , R ¹¹ and R ¹² is connected to each other by two substituents, each of which is a fluoroalkyl group or an aryl group having 6 to 30 carbon atoms). A saturated or unsaturated ring may be formed, Ar ¹ is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, t Is an integer from 0 to 2.)

(In the general formula (14), R ^{14 to} R ²² are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted carbon atom having 1 to 12 carbon atoms. An alkoxy group, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted alkenyl group having 6 to 30 carbon atoms, —OR ²³ (R ²³ is an alkyl group having 1 to 10 carbon atoms, perfluoro R ^{14 to} R ¹⁸ , R ¹⁹ and R ²⁰ , and R ²¹ and R ²² each have two substituents linked to each other. An alkyl group or an aryl group having 6 to 30 carbon atoms). X ¹ may be a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, an unsaturated hydrocarbon group having an aryl group having 6 to 30 carbon atoms, or a carbon number 10 to 30 condensed polycyclic hydrogen groups.)

R ¹⁶ and R ²⁰ may be a substituent represented by the following general formula (14 ′) in addition to the above-described substituents.

(In the general formula (14 ′), Ar ² and Ar ³ are a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and u is It is an integer from 0 to 2.)

(In the general formula (15), R ^{24 to} R ³⁵ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted carbon atom having 1 to 12 carbon atoms. An alkoxy group, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted alkenyl group having 6 to 30 carbon atoms, -OR ³⁶ (R ³⁶ is an alkyl group having 1 to 10 carbon atoms, perfluoro R ^{24 to} R ²⁸ , R ²⁹ and R ³⁰ , and R ³¹ and R ³² each have two substituents linked to each other. May form a saturated or unsaturated ring, and X ² is a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, an unsaturated hydrocarbon group having an aryl group having 6 to 30 carbon atoms, or a carbon number 10 to 30 condensed polycyclic hydrogen groups.)

R ²⁶ may be a substituent represented by the following general formula (15 ′) in addition to the above-described substituent.

(In the general formula (15 ′), Ar ⁴ and Ar ⁵ are a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and v is It is an integer from 0 to 2.)

(In the general formula (16), R ^{37 to} R ⁴⁶ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon number 1 to 12 An alkoxy group, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted alkenyl group having 6 to 30 carbon atoms, —OR ⁴⁷ (R ⁴⁷ is an alkyl group having 1 to 10 carbon atoms, perfluoro R ^{37 to} R ⁴¹ , R ⁴² and R ⁴³ , and R ⁴⁵ and R ⁴⁶ each have two substituents each other, which is an alkyl group or an aryl group having 6 to 30 carbon atoms). They may be linked to form a saturated or unsaturated ring, and Ar ⁴ and Ar ⁵ are each a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon group having 6 to 30 carbon atoms. And w is an integer of 0 to 2.)

Moreover, it is preferable to make the molecular weight of a positive hole transport agent into the value within the range of 300-2,000.
The reason for this is that not only the film thickness variation is reduced by using a hole transport agent having such a molecular weight range, but also not only in the initial stage but also after carrying out a predetermined continuous printing, the photoreceptor layer. This is because the sensitivity characteristic can be maintained.
In addition, the hole transport agent having such a molecular weight range is not only easy to handle, but also has little crystallization and excellent durability.
Therefore, among the specific examples of the hole transport agent described above, a compound having a molecular weight of 300 to 2,000 is more preferable.
The molecular weight of the hole transport agent can be calculated based on, for example, the structural formula, or can be measured using a mass spectrum obtained with a mass spectrometer.

(2) -3 Specific Example 2
Specific examples of the hole transporting agent include compounds (HTM-1 to 4) represented by the following formulas (17) to (20).

(2) -4 Addition amount The addition amount of the hole transport agent is set to a value in the range of 1 to 100 parts by weight with respect to 100 parts by weight of the binder resin.
This is because, when the amount of the hole transport agent added is less than 1 part by weight, the sensitivity characteristics in the photoreceptor layer may not be maintained after the predetermined continuous printing is performed.
On the other hand, when the added amount of the hole transport agent exceeds 100 parts by weight, it may be difficult to uniformly mix and disperse or it may be easy to crystallize.
Therefore, it is more preferable to set the addition amount of the hole transport agent to a value in the range of 5 to 80 parts by weight, and to a value in the range of 10 to 50 parts by weight with respect to 100 parts by weight of the binder resin. More preferably.

(3) Binder resin (3) -1 Weight average molecular weight As the type of the binder resin constituting the charge transport layer, when the charge transport layer corresponds to the surface layer, the first is different in molecular structure. A polycarbonate resin and a second polycarbonate resin are used.
At that time, the weight average molecular weight of the plurality of polycarbonate resins is not particularly limited. For example, the weight average molecular weight of the first polycarbonate resin is increased and the weight average molecular weight of the second polycarbonate resin is decreased. Thus, it is preferable to use a plurality of polycarbonate resins having different weight average molecular weights.
The reason for this is that, as described above, the effect that the triphenylamine compound as an additive is selectively compatible with a specific molecular structure as described above can be more effectively exhibited. Because. That is, the triphenylamine compound as an additive is selectively compatible with a polycarbonate resin having a relatively small weight average molecular weight, but is relatively incompatible with a polycarbonate resin having a relatively large weight average molecular weight. More specifically, it is preferable to use together the 1st polycarbonate resin whose weight average molecular weight is 40,000 or more, and the 2nd polycarbonate resin whose weight average molecular weight is less than 40,000.

(3) -2 Mixing ratio In addition, when the first polycarbonate resin and the second polycarbonate resin having different molecular structures are used in combination, when the second polycarbonate resin is 100 parts by weight, the first polycarbonate resin The addition amount is preferably set to a value within the range of 10 to 80 parts by weight.
For example, when the second polycarbonate resin represented by formula (7) or formula (8) is 100 parts by weight, the addition amount of the first polycarbonate resin represented by formula (6) is 10 to 80 wt. Part.
This is because, when the amount of the first polycarbonate resin represented by the formula (6) is less than 10 parts by weight, it becomes difficult to exert interaction with the triphenylamine compound as an additive. This is because there are cases. Moreover, when the addition amount of the 1st polycarbonate resin represented by Formula (6) exceeds 80 weight part, the addition amount of the 2nd polycarbonate resin represented by Formula (7) or Formula (8) is relative. This is because the durability and wear resistance may be significantly reduced.
Therefore, it is more preferable that the amount of the first polycarbonate resin added is within a range of 20 to 50 parts by weight with respect to 100 parts by weight of the second polycarbonate resin.

(3) -3 types In addition, the present invention is characterized in that a first polycarbonate resin and a second polycarbonate resin having different molecular structures are used. This is because such a plurality of polycarbonate resins can exhibit the interaction with the triphenylamine compound as an additive more effectively.
That is, for example, a triphenylamine compound as an additive is represented by a polycarbonate resin containing a cyclo ring structure as represented by the formula (7) as a second polycarbonate resin, or a formula (8). While the resin is selectively compatible with a polycarbonate resin having an asymmetric structure at its central portion, it is relatively compatible with the polycarbonate resin of the copolymer represented by the formula (6) as the first polycarbonate resin. This is because it is difficult.
Therefore, by using a plurality of polycarbonate resins each having a different molecular structure, it is possible to effectively prevent cracking and crystallization due to adhesion of finger oil or the like while maintaining mechanical strength and durability.

Moreover, as a suitable example of the 1st polycarbonate resin which has a structural unit of General formula (6), the polycarbonate resin represented by Formula (21)-(23) can be mentioned.
Moreover, as a suitable example of the 2nd polycarbonate resin which has a structural unit of General formula (7), (8), the polycarbonate resin represented by Formula (24)-(26) can be mentioned, respectively.

Moreover, it is preferable to use a plurality of polycarbonate resins having different I / O values.
The reason for this is that a plurality of polycarbonate resins having different I / O values can exhibit the interaction with the triphenylamine compound as an additive more effectively. That is, the triphenylamine compound as an additive is selectively compatible with a polycarbonate resin having an I / O value of 0.37 or more, while being compared with a polycarbonate resin having an I / O value of less than 0.37. This is because they are not compatible with each other.
Therefore, by using a plurality of polycarbonate resins having not only different molecular structures but also different I / O values, the occurrence of cracks and crystallization due to adhesion of finger oil etc. is maintained while maintaining mechanical strength and durability. It can be effectively prevented.
Therefore, since the interaction with the triphenylamine compound as the additive can be more effectively exhibited, the polycarbonate resin having an I / O value of 0.38 to 0.45, and the I / O value of 0.1. It is more preferable to use together with a polycarbonate resin of 30 to 0.37.
The polycarbonate resin having an I / O value of 0.37 or more is used as the first polycarbonate resin, and the polycarbonate resin having an I / O value of less than 0.37 is used as the second polycarbonate resin. Is preferred.
This is because the compatibility with the plasticizer component due to the I / O value can be matched with the compatibility with the plasticizer component due to the molecular structure, and the plasticizer can further prevent cracks. This is because it can be effectively exhibited.

Here, the concept of the I / O value will be described in detail. For example, KUMAMOTO PHARMACEUTICAL BULLETIN, No. 1, No. 1-16 (1954); Chemistry, Vol. 11, No. 10, No. 719- 725 (1957); Fragrance Journal, 34, 97-111 (1979); Fragrance Journal, 50, 79-82 (1981); Yes.
That is, one carbon (C) is organic 20, and based on that, the inorganic value and organic value of each polar group are determined as shown in Table 1, and the sum of nonpolar values in each polar group (I value) Then, the sum of organic values (O value) is obtained and the respective ratios are taken as I / O values.
In Table 1, R mainly represents an alkyl group, and φ mainly represents an alkyl group or an aryl group. As can be easily understood from this table, the closer the I / O value is to 0, the more non-polar (hydrophobic and organic) organic compounds are shown, and the higher the I / O value, the more polar (hydrophilic) It can be said that it is an organic compound having a large property and inorganic property.

  In addition, such I / O values divide the properties of compounds into organic groups that exhibit covalent bonding and inorganic groups that exhibit ionic bonding, and all organic compounds are named as organic and inorganic axes. It can be said that the index is located at each point on the orthogonal coordinates. That is, the inorganic value is obtained by quantifying the magnitude of the influence of various substituents and bonds of an organic compound on the boiling point based on the hydroxyl group. Specifically, when the distance between the boiling point curve of the linear alcohol and the boiling point curve of the linear paraffin is about 100 ° C., the influence of one hydroxyl group is set to 100 as a numerical value. Based on this numerical value, the value obtained by quantifying the influence of various substituents or various bonds on the boiling point is the inorganic value of the substituent that the organic compound has. For example, as shown in Table 1, the inorganic value of the —COOH group is 150, and the inorganic value of the double bond is 2. Therefore, the inorganic value of a certain organic compound means the sum of inorganic values such as various substituents and bonds of the organic compound.

On the other hand, the organic value is determined based on the influence of the methylene group in the molecule as a unit and the boiling point of the carbon atom representing the methylene group. That is, since the average value of the boiling point increase due to addition of one carbon in the vicinity of 5 to 10 carbon atoms of the linear saturated hydrocarbon compound is 20 ° C., the organic value of one carbon atom is set to 20, As a standard, the organic value is a value obtained by quantifying the influence of various substituents and bonds on the boiling point. For example, as shown in Table 1, the organic value of the nitro group (—NO ₂ ) is 70. Therefore, the inorganic value of a certain organic compound means the sum of organic values such as various substituents and bonds of the organic compound.
Therefore, although the polycarbonate resin represented by Resin-1 described later is a representative example of a binder resin that can be used in the present invention, the I / O value of this polycarbonate resin is calculated as follows.

(Organic value)
-It has 13 organic carbon atoms of 13x0.15 + 15x0.85 = 14.7.
-It has 0.85 organic-10 Iso branches.
Therefore, the organic value is 20 × 14.7−10 × 0.85 = 285.5.
(Inorganic value)
-It has two benzene rings with an inorganicity of 15.
-It has one O-COO with inorganicity of 80.
Therefore, the inorganic value of the polycarbonate resin represented by Resin-1 is 15 × 2 + 80 = 110, and the I / O value is obtained as 110 / 285.5 = 0.385.

In addition, as the binder resin constituting the charge transport layer, various resins conventionally used in the photosensitive layer can be used in combination with the polycarbonate resin described above.
For example, polyester resin, polyarylate resin, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic copolymer, styrene-acrylic acid copolymer, polyethylene, ethylene- Vinyl acetate copolymer, chlorinated polyethylene, polyvinyl chloride, polypropylene, ionomer, vinyl chloride-vinyl acetate copolymer, alkyd resin, polyamide, polyurethane, polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin Resin such as thermoplastic resin such as silicone resin, epoxy resin, phenol resin, urea resin, melamine resin, other cross-linkable thermosetting resin, epoxy acrylate, urethane acrylate, etc. A.

(4) Triphenylamine compound as additive The triphenylamine compound as additive is preferably a compound represented by formula (27) or a derivative thereof (TPA-1 to 21).

Moreover, it is preferable to make content of the triphenylamine compound as such an additive into the value within the range of 1-30 weight part with respect to 100 weight part of binder resin in a charge transport layer.
This is because, when the content of the triphenylamine compound as the additive is less than 1 part by weight, it may be difficult to selectively dissolve with one polycarbonate resin. On the other hand, if the content of the triphenylamine compound as the additive exceeds 30 parts by weight, the proportion compatible with the other polycarbonate resin increases, and the mechanical strength and durability may be significantly reduced. It is.
Therefore, the content of the triphenylamine compound as an additive is more preferably set to a value in the range of 2 to 20 parts by weight with respect to 100 parts by weight of the binder resin in the charge transport layer, and 3 to 15 parts by weight. More preferably, the value is within the range of parts.

(5) Other additives In addition to the above components, various conventionally known additives such as hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, and spiro are known as antioxidants. Indanone and derivatives thereof, organic sulfur compounds, organic phosphorus compounds and the like are used. Examples of the light stabilizer include derivatives such as benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine. In addition, radical scavengers, singlet quenchers, deterioration inhibitors such as UV absorbers, softeners, additives, surface modifiers, extenders, thickeners, dispersion stabilizers, waxes, acceptors, donors, etc. Can be blended. In order to improve the sensitivity of the photosensitive layer, for example, known sensitizers such as halonaphthoquinones and acenaphthylene may be used in combination with the charge generator.

(6) Photoreceptor characteristics (6) -1 95% response time Further, 95% response time (wavelength 780 nm corresponding to charge voltage becoming 100 V after 300 msec after charging under conditions of 23 ° C. and 700 V) Depending on the exposure amount, the time until the charging voltage reaches 130 V is preferably set to a value within 20 msec.
This is because the predetermined sensitivity characteristic can be stably obtained by such a configuration.
Accordingly, the 95% response time is more preferably set to a value within 15 msec, and further preferably set to a value within 10 msec.

(6) -2 Glass transition point The glass transition point (DSC measurement) of the photosensitive layer is preferably set to a value of 65 ° C or higher.
The reason for this is that, by configuring in this way, not only the wear resistance and sensitivity characteristics are stably improved, but also crack generation and crystallization due to adhesion of finger oil etc. can be further effectively prevented. It is.
Accordingly, the glass transition point is more preferably set to a value within the range of 70 to 120 ° C, and further preferably set to a value within the range of 75 to 100 ° C.

(7) Manufacturing method The manufacturing method of the multilayer electrophotographic photosensitive member is not particularly limited, but preferably includes the following steps (a) to (c), for example.
(A) A step of forming an intermediate layer on the conductive support (sometimes referred to as an intermediate layer forming step).
(B) A step of forming a charge generation layer by applying a charge generation layer coating solution containing a binder resin, a charge generation material, and a solvent on the intermediate layer (referred to as a charge generation layer formation step). There may be cases.)
(C) A step of forming a charge transport layer by applying a charge transport layer coating solution containing a plurality of polycarbonate resins, a charge transport agent and a solvent on the charge generation layer (sometimes referred to as a charge transport layer forming step). is there.)
The present invention can be applied to both the charge generation layer and the charge transport layer, but is preferably applied to the charge transport layer on the outermost surface side.

(7) -1 Intermediate layer forming step In forming the intermediate layer, a binder resin and, if necessary, an additive (organic fine powder or inorganic fine powder) together with an appropriate dispersion medium, a known method such as a roll mill or a ball mill. The coating liquid is prepared by dispersing and mixing using an attritor, paint shaker, ultrasonic disperser, etc., and this is applied by a known means such as a blade method, a dipping method, or a spray method, followed by heat treatment to form an intermediate layer. Form. In addition, the additive is in a range where precipitation during production does not become a problem, and various additives (organic fine powder or inorganic fine powder are used for the purpose of preventing the occurrence of interference fringes by causing light scattering. ) Is preferably added in a small amount.
Next, the obtained coating solution is applied to a support substrate (aluminum base tube) according to a known production method, such as dip coating, spray coating, bead coating, blade coating, roller coating, etc. It is preferable to apply using an application method.
Thereafter, the step of drying the coating solution on the support substrate is desirably performed at a temperature of 20 to 200 ° C. for 5 minutes to 2 hours.

  In addition, as a solvent for making such a coating liquid, various organic solvents can be used, for example, alcohols such as methanol, ethanol, isopropanol and butanol; aliphatic hydrocarbons such as n-hexane, octane and cyclohexane. Aromatic hydrocarbons such as benzene, toluene and xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride and chlorobenzene; ketones such as acetone, methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate and methyl acetate Dimethylformaldehyde, dimethylformamide, dimethyl sulfoxide and the like. These solvents are used alone or in admixture of two or more.

(7) -2 Charge Generation Layer Formation Step Next, in preparing the charge generation layer, a dispersion treatment method is not particularly limited, but generally known roll mills, ball mills, and vibration ball mills are not limited. It is preferable to use an attritor, a sand mill, a colloid mill, a paint shaker or the like.
Next, the obtained coating solution is applied to the surface of the intermediate layer that has already been formed. As this coating method, for example, it is preferable to use a coating method such as a dip coating method, a spray coating method, a bead coating method, a blade coating method, or a roller coating method.
Thereafter, the step of drying the coating solution on the surface of the intermediate layer is desirably performed at a temperature of 20 to 200 ° C. for 5 minutes to 2 hours.

Further, as described above, a mixed solvent of propylene glycol monoalkyl ether and a cyclic ether compound can be used as the solvent of the coating solution. In addition, in order to improve the dispersibility of the charge generating agent and the smoothness on the surface of the photoreceptor layer, a surfactant, a leveling agent, and the like can be added when the coating solution is prepared.
The solvent amount of the coating solution is preferably added in the range of 1,000 to 50,000 parts by weight with respect to 100 parts by weight of the binder resin of the charge generation layer.

(7) -3 Step of forming charge transport layer Next, in forming the charge transport layer, a charge transport agent or the like is added to the solution in which the resin component is dissolved, and a dispersion treatment is performed to form a coating solution. Is preferred.
Next, the obtained coating solution is applied to the surface of the charge generation layer that has already been formed. As this coating method, for example, it is preferable to use a coating method such as a dip coating method, a spray coating method, a bead coating method, a blade coating method, or a roller coating method.
Thereafter, the step of drying the coating solution on the surface of the charge generation layer is desirably performed at a temperature of 20 to 200 ° C. for 5 minutes to 2 hours.

  In addition, various organic solvents can be used as a solvent for preparing such a coating solution, for example, alcohols such as methanol, ethanol, isopropanol and butanol; aliphatic hydrocarbons such as n-hexane, octane and cyclohexane. Aromatic hydrocarbons such as benzene, toluene and xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride and chlorobenzene; ketones such as acetone, methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate and methyl acetate Dimethylformaldehyde, dimethylformamide, dimethyl sulfoxide and the like. These solvents are used alone or in admixture of two or more. Moreover, a leveling agent etc. can also be used as needed.

  In addition, the positive or negative charge type of the multilayer photoconductor is selected depending on the order of forming the charge generation layer and the charge transport layer and the type of charge transport agent used in the charge transport layer. For example, as shown in FIG. 1, when a charge generation layer 24 is formed on a substrate 12 and a charge transport layer 22 is formed thereon, an amine compound derivative or a stilbene derivative is used as a charge transport agent in the charge transport layer 22. When a positive hole transport agent is used, the photoreceptor becomes a negatively charged type. In this case, the charge generation layer 24 may contain an electron transport agent. In such a laminated electrophotographic photosensitive member, the residual potential of the photosensitive member is greatly reduced, and the sensitivity can be improved.

[Second Embodiment]
In the second embodiment of the present invention, as illustrated in FIG. 2, an electron including a single layer type photosensitive layer 26 containing at least a hole transport agent and a binder resin on a conductive substrate 12. The photographic photoreceptor 30 includes a first polycarbonate resin and a second polycarbonate resin having different molecular structures as binder resins, and the photosensitive layer contains a triphenylamine compound as an additive. An electrophotographic photosensitive member is characterized.
Hereinafter, an electrophotographic photosensitive member as a single-layer type photosensitive member according to the second embodiment of the present invention will be specifically described.

1. Basic Configuration The type of the basic configuration in the single layer type photoreceptor is not particularly limited, but the thickness of the photoreceptor layer is usually a value in the range of 5 to 100 μm, preferably 10 to 50 μm. It is a value within the range.
In addition, a plurality of polycarbonate resins having different weight average molecular weights constituting the single layer type photoreceptor and the kind of triphenylamine compound as an additive are not particularly changed. The value is preferably in the range of 0.1 to 15 parts by weight with respect to 100 parts by weight of the binder resin.

As the conductive substrate on which such a photoreceptor layer is formed, various conductive materials can be used, for example, iron, aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium. , Cadmium, titanium, nickel, palladium, indium, stainless steel, brass and the like, plastic materials on which the above metal is deposited or laminated, glass covered with aluminum iodide, tin oxide, indium oxide, etc. .
Further, the shape of the conductive substrate may be any of a sheet shape, a drum shape, or the like in accordance with the structure of the image forming apparatus to be used. The substrate itself is conductive or the surface of the substrate is conductive. As long as it has. The conductive substrate preferably has sufficient mechanical strength when used. When the photoreceptor layer is formed by a coating method, the above-described charge generator, charge transport agent, binder resin and the like together with a suitable solvent, a known method such as a roll mill, a ball mill, an attritor, a paint shaker, A dispersion liquid may be prepared by dispersing and mixing using an ultrasonic disperser or the like, and this may be applied and dried by a known means.
Furthermore, with respect to the configuration of the single-layer type photoreceptor, a barrier layer may be formed between the conductive substrate and the photoreceptor layer as long as the characteristics of the photoreceptor are not impaired. Further, a protective layer may be formed on the surface of the photoreceptor.

2. Manufacturing Method The manufacturing method of the single layer type photoreceptor is not particularly limited, but it is preferable to prepare a coating solution first. Then, the obtained coating solution is applied, for example, on a conductive base material (aluminum base tube) by a dip coating method according to a known production method, and dried with hot air, for example, at 100 ° C. for 30 minutes. Thus, an electrophotographic photosensitive member having a photosensitive layer having a predetermined thickness can be obtained.
In addition, as a solvent for making a dispersion liquid, various organic solvents can be used, for example, alcohols such as methanol, ethanol, isopropanol and butanol; aliphatic hydrocarbons such as n-hexane, octane and cyclohexane; Aromatic hydrocarbons such as benzene, toluene, xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride, chlorobenzene; dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, 1,3-dioxolane Ethers such as 1,4-dioxane, ketones such as acetone, methyl ethyl ketone, and cyclohexanone; esters such as ethyl acetate and methyl acetate; dimethylformaldehyde, dimethyl Examples include tilformamide and dimethyl sulfoxide. These solvents are used alone or in admixture of two or more.
Further, a surfactant, a leveling agent or the like may be used in order to improve the dispersibility of the charge generator and the smoothness of the surface of the photoreceptor layer.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these description content.

[Example 1]
1. Production of Electrophotographic Photoreceptor An intermediate layer, a charge generation layer, and a charge transport layer were sequentially formed on a conductive support to produce a multilayer electrophotographic photoreceptor of Example 1.

(1) Formation of intermediate layer The intermediate layer is 250 parts by weight of titanium oxide (MT-02, alumina, silica, number-average primary particle diameter 10 nm (manufactured by Teika) surface-treated with methylhydrogenpolysiloxane), quaternary copolymerization. Add 100 parts by weight of polyamide resin CM8000 (manufactured by Toray), 1000 parts by weight of methanol as a solvent and 250 parts by weight of n-butanol, disperse for 10 hours using a paint shaker, and further filter through a 5 micron filter. Thus, an intermediate layer coating solution was prepared.
Next, one end of an aluminum substrate (supporting substrate) having a diameter of 30 mmφ and a length of 238.5 mm was placed on the upper side, and was applied by being immersed in the obtained intermediate layer coating solution at a rate of 5 mm / sec. Thereafter, heat treatment was performed at 130 ° C. for 30 minutes to form an intermediate layer having a thickness of 2 μm.

(2) Preparation of charge generation layer and charge transport layer (2) -1 Preparation of coating solution for charge generation layer 100 parts by weight of titanyl phthalocyanine represented by formula (10) and polyvinyl acetal resin have a weight average molecular weight of 130. , 100 parts by weight of Resin KS-5 (manufactured by Sekisui Chemical Co., Ltd.), 6000 parts by weight of propylene glycol monomethyl ether as a mixed solvent, and 2000 parts by weight of tetrahydrofuran, and then stirred for 48 hours using a ball mill. It filtered with the micron filter, and was set as the coating liquid for charge generation layers.

In addition, the titanyl phthalocyanine represented by Formula (10) used in Example 1 was manufactured as follows.
That is, 25 g of o-phthalonitrile, 28 g of titanium tetrabutoxide, and 300 g of quinoline were added to a flask purged with argon, and the temperature was raised to 150 ° C. while stirring.
Next, while evaporating the vapor generated from the reaction system, the temperature was raised to 215 ° C. while stirring, and the mixture was further stirred for 2 hours while maintaining this temperature.
After completion of the reaction, when the reaction mixture is cooled to 150 ° C., the reaction mixture is removed from the flask, filtered through a glass filter, and the resulting solid is washed successively with N, N-dimethylformamide and methanol and then vacuum-dried. 24 g of a violet solid was obtained. (Pigmentation pretreatment)
10 g of the blue-purple solid obtained by the synthesis of the titanyl phthalocyanine compound was added to 100 ml of N, N-dimethylformamide, heated to 130 ° C. with stirring, and stirred for 2 hours.
Next, heating was stopped when 2 hours passed, and after cooling to 23 ± 1 ° C., stirring was also stopped. In this state, the liquid was allowed to stand for 12 hours for stabilization treatment.
The stabilized liquid was filtered with a glass filter, and the resulting solid was washed with methanol and then vacuum dried to obtain 9.83 g of a crude crystal of a titanyl phthalocyanine compound.

Subsequently, 5 g of crude crystals of titanyl phthalocyanine obtained by the pre-pigmentation treatment were added to 100 ml of concentrated sulfuric acid and dissolved.
Next, this solution was added dropwise to ice-cooled water, stirred for 15 minutes at room temperature, and then allowed to stand at about 23 ± 1 ° C. for 30 minutes for recrystallization.
Next, the above liquid is filtered off with a glass filter, and the obtained solid is washed with water until the washing liquid becomes neutral, and then dispersed in 200 ml of chlorobenzene in the presence of water without being dried, and 50 ° C. And stirred for 10 hours.
The liquid was filtered off with a glass filter, and the obtained solid was vacuum-dried at 50 ° C. for 5 hours to obtain 4.1 g of titanyl phthalocyanine crystals (blue powder).
This titanyl phthalocyanine does not generate peaks at Bragg angles 2θ ± 0.2 ° = 7.4 ° and 26.2 ° even when immersed in 1,3-dioxolane or tetrahydrofuran for 7 days. It was confirmed. Further, it was confirmed that there was no peak of temperature change from 50 ° C. to 400 ° C. except for the peak around 90 ° C. accompanying vaporization of adsorbed water.

(2) -2 Preparation of coating solution for charge transport layer Further, using 610 parts by weight of tetrahydrofuran, 70 parts by weight of a stilbene compound (HTM-1) represented by formula (17) as a hole transport agent, and an additive As a binder resin, 20 parts by weight of a triphenylamine compound (TPA-2) and a polycarbonate resin represented by the formula (21) having a weight average molecular weight of 32,000 30 parts by weight of (Resin-1) and 70 parts by weight of (Resin-4) which is a bisphenol Z-type polycarbonate resin having a weight average molecular weight of 30500 represented by the formula (24) are uniformly dissolved to form a charge transport layer A coating solution was obtained.

(2) -3 Formation of Charge Generation Layer and Charge Transport Layer After applying the charge generation layer coating solution on the intermediate layer formed on the support substrate using a fluororesin blade, 80 ° C., 5 minutes The charge generation layer having a thickness of 0.3 μm was formed by drying under the above conditions.
Next, the prepared charge transport layer coating solution is applied onto the charge generation layer in the same manner as the charge generation layer coating solution, and dried at 130 ° C. for 30 minutes to form a charge transport layer having a thickness of 20 μm. Formed.

2. Evaluation of electrophotographic photosensitive member The electrophotographic photosensitive member thus prepared was mounted on a commercially available printer (a laser printer manufactured by Oki Electric Co., Microline-22) employing a negatively charged reversal development process, and the electrical characteristics and the amount of wear were evaluated.
(1) Charging potential (Vo)
The obtained electrophotographic photosensitive member was mounted on a printer, and the charging potential (Vo) at this time was measured. The obtained results are shown in Table 2.

(2) Sensitivity (VL)
The obtained electrophotographic photosensitive member was mounted on a printer, charged to −850 (V), and the potential at the development position at the time of black solid image formation was read to obtain a light potential (V) as sensitivity. The obtained results are shown in Table 2.

(3) Amount of wear The amount of wear of the obtained electrophotographic photosensitive member was measured. That is, the difference in the photosensitive layer thickness before and after continuous printing of 10000 sheets of A4 size paper was defined as the amount of wear. An eddy current film thickness meter was used to measure the photosensitive layer thickness.

(4) Finger oil adhesion test (48Hrs, 96Hrs)
The obtained electrophotographic photosensitive member was subjected to finger oil adhesion test after 48 hours and 96 hours. That is, (the finger was pressed against the surface of the photosensitive layer, and the surface of the photosensitive layer after storage for 48 hours in an environment of 23 ° C. and 50% was visually judged.
◎: No occurrence of crack ○: Less than 1 occurrence of cracks at a level that can be observed with a microscope △: Less than 5 occurrences of cracks that can be visually confirmed ×: More than 6 occurrences of cracks that can be visually confirmed

(5) Photoresponsive evaluation The photoresponsiveness of the obtained multilayer electrophotographic photosensitive member was evaluated. That is, when a drum sensitivity tester (Gentec) is used and the photosensitive member is charged to −700 V, the photosensitive member is a xenon flash lamp (pulse width: 50 nm, light having a wavelength of 780 nm is irradiated using a filter). The amount of light was tentatively set so that the surface potential after 300 msec from the start of irradiation was 100V. Next, the time required for the surface potential to reach 130 V (95% responsiveness) when the photoconductor was irradiated with the light amount under such setting conditions was measured as photoresponsiveness.
In addition, it has been found that there is no practical problem with respect to sensitivity if such photoresponsiveness is a value within 20 msec. Furthermore, if such photoresponsiveness is a value within 10 msec, it has excellent sensitivity. It can be said that.

[Examples 2 to 13, Comparative Examples 1 to 8]
In Examples 2 to 14, as shown in Table 2, electrophotographic photosensitive members were prepared in the same manner as in Example 1 except that the type of binder resin and the type of triphenylamine compound as an additive were changed. And evaluated.
On the other hand, in Comparative Examples 1 to 8, as shown in Table 2, Example 1 except that a triphenylamine compound as an additive was not added or a plurality of polycarbonate resins were not used as a binder resin. An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above.
In addition, the weight average molecular weights of the polycarbonate resins used in Examples 2 to 13 and Comparative Examples 1 to 8 are 32000 (Resin-1), 32000 (Resin-2), 31000 (Resin-3), and 30500 (Resin), respectively. -4), 31700 (Resin-5), 31200 (Resin-6).

According to the electrophotographic photoreceptor of the present invention, the first and second polycarbonate resins having different molecular structures are used as the binder resin, and a triphenylamine compound having a predetermined structure is contained as an additive. Therefore, the occurrence of cracks and crystallization of the photosensitive layer due to adhesion of finger oil is reduced while maintaining a predetermined wear resistance.
Therefore, the electrophotographic photosensitive member of the present invention is expected to contribute to high durability, high speed, high performance, etc. in various image forming apparatuses such as copying machines and printers.

FIG. 2 is a diagram for explaining a schematic configuration of a multilayer electrophotographic photosensitive member according to the present invention. FIG. 2 is a diagram for explaining a schematic configuration of a single layer type electrophotographic photosensitive member according to the present invention.

Explanation of symbols

12: substrate, 20: multilayer electrophotographic photosensitive member, 22: charge transport layer, 24: charge generation layer, 25: intermediate layer, 26: photosensitive layer, 30: single layer type electrophotographic photosensitive member

Claims (8)

An electrophotographic photosensitive member comprising a single layer type or a laminated type photosensitive layer containing at least a hole transport agent and a binder resin on a conductive substrate,
The binder resin includes a first polycarbonate resin and a second polycarbonate resin, each having a different molecular structure,
The electrophotographic photoreceptor, wherein the photosensitive layer contains a triphenylamine compound represented by the following general formula (1) as an additive.

(In the general formula (1), Ra, Rb, and Rc are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon number of 1 to 12 An alkoxy group, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, and the repeating numbers k, l and m are integers of 0 to 5. is there.) When the photosensitive layer is a single layer type, the content of the additive is set to a value within the range of 0.1 to 15 parts by weight with respect to 100 parts by weight of the binder resin.
2. The electrophotographic photosensitive member according to claim 1, wherein when the photosensitive layer is a laminated type, the value is in a range of 1 to 30 parts by weight with respect to 100 parts by weight of the binder resin in the surface layer. body. The electrophotographic photoreceptor according to claim 1 or 2, wherein the additive is a compound represented by the following formulas (2) to (5) or a derivative thereof.

The polycarbonate resin represented by the following general formula (6) is included as the first polycarbonate resin, and the polycarbonate resin represented by the following general formula (7) or (8) is included as the second polycarbonate resin. The electrophotographic photosensitive member according to claim 1.

(In the general formula (6), Rd and Re are each an independent hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, and the suffixes n and o are Each independently represents an integer of 0 to 4; Rf and Rg are a hydrogen atom or an alkyl group having 1 to 2 carbon atoms; W is a single bond or —O— or —CO—; Is a molar ratio that satisfies the relational expression of 0.05 <q / (q + p) <0.6.)

(In the general formula (7), a plurality of substituents Rh are a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. r is an integer of 0-4.)

(In the general formula (8), the plurality of substituents Ri are a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. s is an integer of 0-4.)   The electrophotographic photosensitive member according to claim 1, wherein a 95% response time of the photosensitive layer is set to a value within 20 msec.   The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer has a glass transition point of 65 ° C. or more.   The electrophotographic photoreceptor according to claim 1, wherein the hole transport agent is a bisstilbene compound or a bisbutadiene compound.   8. The electrophotographic photosensitive member according to claim 7, wherein the bis-stilbene compound or the bis-butadiene compound has a symmetric structure.

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