JP2005164974A - Electrophotographic photoreceptor, method for manufacturing electrophotographic photoreceptor, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having excellent sensitivity characteristics and to provide its manufacturing method and an image forming apparatus equipped with the electrophotographic photoreceptor. <P>SOLUTION: The electrophotographic photoreceptor has a photosensitive layer containing a binder resin, a hole transporting agent, an electron transporting agent and a charge generating agent. The method for manufacturing the photoreceptor, and the image forming apparatus equipped with the above electrophotographic photoreceptor are also presented. The photoreceptor contains a phenanthrene quinone compound expressed by general formula (1) as the electron transporting agent, wherein each of R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>, R<SP>4</SP>independently represents a 1-6C substituted or unsubstituted alkyl group, 6-12C substituted or unsubstituted aryl group, 6-12C substituted or unsubstituted aralkyl group, 3-10C substituted or unsubstituted cycloalkyl group or 1-6C substituted or unsubstituted alkoxy group. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photosensitive member, a method for producing an electrophotographic photosensitive member, and an image forming apparatus, and in particular, an electrophotographic photosensitive member having excellent sensitivity characteristics, a method for producing the same, and an image including such an electrophotographic photosensitive member. The present invention relates to a forming apparatus.

Conventionally, an organic photoconductor (OPC) composed of a binder resin (binder resin), a charge generator, and a charge transport agent (hole transport agent, electron transport agent) has been used as an electrophotographic photoreceptor for an image forming apparatus. Has been. Such an organic photoreceptor is advantageous in that it is easy to manufacture and has a wide degree of freedom in structural design because it has various options for the photoreceptor material as compared with conventional inorganic photoreceptors.
However, among materials used in organic photoreceptors, electron transport agents generally have insufficient sensitivity characteristics, and it is difficult to exhibit sufficient sensitivity characteristics when used as organic photoreceptors. There was a problem.

  Therefore, a quinone derivative represented by the following general formula (17) has been proposed as an electron transport agent in an organic photoreceptor (see, for example, Patent Document 1).

(In general formula (17), R ⁵ may be the same or different from each other, and is a substituted or unsubstituted monovalent hydrocarbon group.)

  Further, a phenanthrene derivative represented by the following general formula (18) has also been proposed as an electron transport agent in an organic photoreceptor (see, for example, Patent Document 2).

(In the general formula (18), R ⁶ , R ⁷ , R ⁸ and R ⁹ are the same or different and each represents an alkyl group, an aryl group or a heterocyclic group, and R ¹⁰ and R ¹¹ are the same or different and represent a hydrogen atom, a halogen atom, An atom, an alkyl group or an aryl group, n represents an integer of 1 to 4)

JP-A-11-311872 (Claims) JP-A-5-148209 (Claims)

However, the quinone derivative described in Patent Document 1 has high charge mobility by itself, but when used in a photoreceptor, the compatibility with the binder resin is insufficient, so that the charge injectability is low. There was a problem that the sensitivity was low and the sensitivity characteristics were insufficient.
Moreover, although the phenanthrene derivative described in Patent Document 2 has a relatively high charge transport ability and photostability, it is necessary to add a large amount of the phenanthrene derivative, and the phenanthrene derivative is easily crystallized. It was observed.
Therefore, the present inventors have discovered the fact that by using a phenanthrenequinone derivative having a specific structure, the charge mobility is high and the sensitivity characteristics are excellent, and the present invention has been completed. .
That is, an object of the present invention is to solve the above-described technical problems, and to provide an electrophotographic photoreceptor excellent in sensitivity characteristics, a method for producing the same, and an image forming apparatus including such an electrophotographic photoreceptor. is there.

  According to the present invention, there is provided an electrophotographic photoreceptor including a photoreceptor layer including a binder resin, a hole transport agent, an electron transport agent, and a charge generation agent. An electrophotographic photoreceptor containing a phenanthrenequinone derivative represented by the formula (1) is provided, and the above-described problems can be solved.

(R ¹ , R ² , R ³ and R ⁴ in the general formula (1) are each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. Group, a substituted or unsubstituted aralkyl group having 6 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms.)

In constituting the phenanthrenequinone derivative of the present invention, R ¹ , R ² , R ³ and R ⁴ in the general formula (1) are preferably a t-butyl group or a methoxy group.

  Further, in constituting the electrophotographic photosensitive member of the present invention, it is preferable that the addition amount of the electron transport agent is set to a value within the range of 10 to 100 parts by weight with respect to 100 parts by weight of the binder resin.

  In constituting the electrophotographic photoreceptor of the present invention, the photoreceptor layer is preferably a single layer type.

Another aspect of the present invention is a method for producing any of the above-described electrophotographic photoreceptors, wherein the binder resin, the hole transport agent, and the phenanthrene represented by the following general formula (1): A step of preparing a coating liquid by mixing and dispersing an electron transporting agent containing a quinone derivative, a charge generating agent, and a solvent;
A step of applying the prepared coating liquid on a conductive substrate;
Drying the conductive substrate coated with the coating solution;
Is a method for producing an electrophotographic photosensitive member.

(R ¹ , R ² , R ³ and R ⁴ in the general formula (1) are each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. Group, a substituted or unsubstituted aralkyl group having 6 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms.)

  Another aspect of the present invention includes any one of the electrophotographic photosensitive members described above, and a portion for performing a charging step, an exposure step, a developing step, and a transfer step around the electrophotographic photosensitive member. This is an arranged image forming apparatus.

According to the electrophotographic photoreceptor of the present invention, an electrophotographic photoreceptor excellent in sensitivity characteristics can be obtained by using a specific phenanthrenequinone derivative as an electron transport agent.
That is, the phenanthrenequinone derivative represented by the general formula (1) has high charge mobility and excellent sensitivity characteristics even when used in an electrophotographic photoreceptor.

  In addition, according to the electrophotographic photosensitive member of the present invention, an electron transporting agent excellent in charge injectability from the charge generating agent can be obtained by the specific phenanthrenequinone derivative having a predetermined substituent. it can. In addition, with such a substituent, it is relatively easy to introduce and a predetermined phenanthrenequinone derivative can be produced in a relatively high yield.

  In addition, according to the electrophotographic photoreceptor of the present invention, by limiting the amount of the electron transport agent added to a predetermined range, crystallization of the electron transport agent can be effectively prevented, and the sensitivity characteristics are also excellent. An electrophotographic photoreceptor can be obtained.

  In addition, according to the electrophotographic photosensitive member of the present invention, by specifying the photosensitive layer as a single layer type, an electrophotographic photosensitive member having excellent sensitivity characteristics can be obtained even though the configuration and manufacture are easy. Can do.

  According to another of the present invention, any one of the above-described methods for producing an electrophotographic photosensitive member, which can efficiently obtain an electrophotographic photosensitive member having excellent sensitivity characteristics by including a specific production step. it can.

  Further, according to another aspect of the present invention, an image forming apparatus including any one of the above-described electrophotographic photosensitive members, which includes an electrophotographic photosensitive member including a specific electron transporting agent, has excellent sensitivity characteristics and is clear. An image forming apparatus capable of forming a stable image can be obtained.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments relating to an electrophotographic photoreceptor, a method for producing the same, and an image forming apparatus according to the present invention will be specifically described below with reference to the accompanying drawings.

[First embodiment]
The first embodiment is an electrophotographic photoreceptor including a photoreceptor layer containing a binder resin, a hole transport agent, an electron transport agent, and a charge generation agent. An electrophotographic photoreceptor containing a phenanthrenequinone derivative represented by the general formula (1).

(R ¹ , R ² , R ³ and R ⁴ in the general formula (1) are each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. Group, a substituted or unsubstituted aralkyl group having 6 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms.)

  Here, the electrophotographic photosensitive member includes a single layer type and a laminated type, and the electrophotographic photosensitive member of the present invention is applicable to both. However, it can be used for both positive and negative chargeability, has a simple structure and is easy to manufacture, and suppresses film defects when forming the photoreceptor layer, so there are few interfaces between layers, improving optical characteristics For reasons such as being possible, it is more preferable to apply to a single layer type.

1. Single Layer Type Photoreceptor (1) Basic Configuration As shown in FIG. 2, the single layer type photoreceptor 10 has a single photoreceptor layer 14 provided on a conductive substrate 12.
This photoreceptor layer includes, for example, a phenanthrenequinone derivative as an electron transporting agent represented by the general formula (1), a binder resin, a hole transporting agent, a charge generating agent, and if necessary. It can be formed by dissolving or dispersing a leveling agent or the like in an appropriate solvent, coating the obtained coating solution on a conductive substrate, and drying. Such a single layer type photoreceptor is characterized in that it can be applied to either a positive or negative charge type with a single configuration, has a simple layer configuration, and is excellent in productivity.

(2) Binder Resin (2) -1 Type As the binder resin for dispersing each component, various resins conventionally used in the photoreceptor layer can be used. For example, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic copolymer, styrene-acrylic acid copolymer, polyethylene resin, ethylene-vinyl acetate copolymer, chlorination Polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer resin, vinyl chloride-vinyl acetate copolymer, polyester resin, alkyd resin, polyamide resin, polyurethane resin, polycarbonate resin, polyarylate resin, polysulfone resin, diallyl phthalate resin, ketone Thermoplastic resins such as resin, polyvinyl butyral resin, polyether resin, polyester resin; silicone resin, epoxy resin, phenol resin, urea resin, melamine resin, other crosslinkable thermosetting resins; epoxy acrylic Over bets, urethane - alone or in combinations of two or more such photocurable resin such as acrylate.
In particular, a polycarbonate resin is a preferable binder resin because it is excellent not only in transparency and heat resistance but also in mechanical properties and compatibility with a hole transport agent.

(3) Hole transport agent (3) -1 type Examples of the hole transport agent suitable for the electrophotographic photoreceptor of the present invention include various hole transport agents conventionally used for photoreceptors. Can do.
Examples of such a hole transport agent include various compounds having high hole transport ability, such as compounds represented by the following general formulas (HTM-1 to HTM-13).

(In the formula, R ^h1 , R ^h2 , R ^h3 , R ^h4 , R ^h5 and R ^h6 are independent and are each a halogen atom, an alkyl group which may have a substituent, or an alkoxy which may have a substituent. Represents an aryl group which may have a group or a substituent, a and b represent the same or different integers of 0 to 4, and c, d, e and f may be the same or different. Represents a good integer of 0 to 5, provided that when a, b, c, d, e or f is 2 or more, each R ^h1 , R ^h2 , R ^h3 , R ^h4 , R ^h5 and R ^h6 are different. May be good.)

Wherein R ^h7 , R ^h8 , R ^h9 , R ^h10 and R ^h11 are the same or different and are a halogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent or a substituent. An aryl group which may have a group, g, h, i and j are the same or different and each represents an integer of 0 to 5, and k represents an integer of 0 to 4, provided that g, h, i, When j or k is 2 or more, each R ^h7 , R ^h8 , R ^h9 , R ^h10 and R ^h11 may be different.)

^{(Wherein, R h12, R h13, R} h14 and R ^h15 are the same or different, a halogen atom, chromatic an optionally substituted alkyl group, an alkoxy group or a substituted group which may have a substituent R ^h16 may be a halogen atom, a cyano group, a nitro group, an alkyl group that may have a substituent, an alkoxy group that may have a substituent, or a substituent. Represents a good aryl group, m, n, o and p are the same or different and represent an integer of 0 to 5. q represents an integer of 0 to 6, provided that m, n, o, p or q is 2. when the above, each ^{R h12, R h13, R h14} , R h15 and R ^h16 may be different.)

( ^Wherein R ^h17 , R ^h18 , R ^h19 and R ^h20 are the same or different and have a halogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent or a substituent. R, s, t and u are the same or different and each represents an integer of 0 to 5, provided that when r, s, t or u is 2 or more, each R ^h17 , R ^h18, R ^h19 and R ^h20 may be different.)

(Wherein R ^h21 and R ^h22 are the same or different and represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. R ^h23 , R ^h24 , R ^h25 and R ^h26 are the same or different and represent a hydrogen atom, an alkyl group, Represents a group or an aryl group.)

(In the formula, R ^h27 , R ^h28 and R ^h29 are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group.)

(In the formula, R ^h30 , R ^h31 , R ^h32 and R ^h33 are the same or different and represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group.)

(In the formula, R ^h34 , R ^h35 , R ^h36 , R ^h37 and R ^h38 are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group.)

( ^Wherein R ^h39 represents a hydrogen atom or an alkyl group, and R ^h40 , R ^h41 and R ^h42 are the same or different and represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group.)

(Wherein, R ^h43, R ^h44 and R ^h45 are the same or different and represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group.)

( ^Wherein R ^h46 and R ^h47 are the same or different and each represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group or an optionally substituted alkoxy group. R ^h48 and R ^h49 Are the same or different and each represents a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent.

(In the formula, R ^h50 , R ^h51 , R ^h52 , R ^h53 , R ^h54 and R ^h55 are the same or different and are an alkyl group which may have a substituent, an alkoxy group which may have a substituent, or a substituent. Represents an aryl group which may have a group, α represents an integer of 1 to 10, and v, w, x, y, z and β are the same or different and represent an integer of 0 to 2, provided that v, When w, x, y, z or β is 2, each R ^h50 , R ^h51 , R ^h52 , R ^h53 , R ^h54 and R ^h55 may be different.)

^Wherein R ^h56 , R ^h57 , R ^h58 and R ^h59 are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group, and Φ-1 to Φ-3 are structures represented by the following formulae .)

  In addition, in the present invention, a conventionally known hole transport material, 2,5-di (4-methyl), together with or instead of the above exemplified hole transport agents (HTM-1) to (HTM-13) Oxadiazole compounds such as aminophenyl) -1,3,4-oxadiazole, styryl compounds such as 9- (4-diethylaminostyryl) anthracene, carbazole compounds such as polyvinyl carbazole, organic polysilane compounds, 1- Pyrazoline compounds such as phenyl-3- (p-dimethylaminophenyl) pyrazoline, hydrazone compounds, triphenylamine compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazoles Compounds, pyrazole compounds, triazole compounds, etc. Or a combination of two or more of nitrogen-containing cyclic compounds and condensed polycyclic compounds.

(3) -2 Addition Amount With respect to the addition amount of the hole transport agent, it is preferable to set the value within a range of 10 to 150 parts by weight with respect to 100 parts by weight of the binder resin.
The reason for this is that when the added amount of the hole transport agent is less than 10 parts by weight, the sensitivity is lowered and a practical problem may occur. On the other hand, when the added amount of the hole transport agent exceeds 150 parts by weight, the hole transport agent is likely to be crystallized, and an appropriate film as a photoreceptor may not be formed.
Therefore, the amount of the hole transport agent added is more preferably set to a value in the range of 20 to 100 parts by weight, and further preferably set to a value in the range of 30 to 80 parts by weight.

(4) Electron Transfer Agent (4) -1 Type As a type of electron transfer agent suitable for the electrophotographic photoreceptor of the present invention, a phenanthrenequinone derivative represented by the general formula (1) is used. And
The reason for this is that by introducing a specific electron transporting agent, the compatibility and solubility with the binder resin and the hole transporting agent are increased, and the electron transporting agent has many double bonds in the structure. In addition, due to the structural features of containing a condensed ring, it has high charge mobility and excellent electron injection from the charge generating agent to the electron transporting agent, resulting in excellent sensitivity characteristics. This is because the residual potential can be made 140V or less.

Moreover, it is preferable that the location represented by R < ¹ >, R < ² >, R < ³ > and R < ⁴ > in a specific electron transport agent is a t-butyl group or a methoxy group.
The reason for this is that by including such a specific substituent, the charge injection property from the charge generator is excellent, and there is little steric hindrance due to the substituent, and the structure is kept stable, resulting in high sensitivity. The characteristics can be provided stably even when used for a long time. Furthermore, such a substituent is relatively easy to introduce and can produce a predetermined phenanthrenequinone derivative in a relatively high yield.

  As specific examples of these electron transfer agents, compounds (ETM-A and ETM-B) represented by the following formulas (2) and (3) are shown. Here, an infrared spectroscopy (IR) chart of the phenanthrenequinone derivative represented by the following formula (2) is shown in FIG.

  Moreover, the synthesis | combination of the phenanthrenequinone derivative represented by Formula (2) was performed according to following Reaction formula (1).

It is also preferable to use a conventionally known electron transport agent in combination. Examples of such electron transporting agents include diphenoquinone derivatives, benzoquinone derivatives, anthraquinone derivatives, malononitrile derivatives, thiopyran derivatives, trinitrothioxanthone derivatives, 3,4,5,7-tetranitro-9-fluorenone derivatives, dinitroanthracene derivatives, Dinitroacridine derivatives, nitroantharaquinone derivatives, dinitroanthraquinone derivatives, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride And various compounds having an electron accepting property such as dibromomaleic anhydride, and one kind or a mixture of two or more kinds may be used.
Of these electron transfer agents, compounds having an electron mobility of 1.0 × 10 ⁻⁸ cm ² / V / sec or more at an electric field strength of 5 × 10 ⁵ v / cm are more preferable.

(4) -2 Addition amount Further, in constituting the electrophotographic photosensitive member, the addition amount of the electron transport agent is set to a value within the range of 10 to 100 parts by weight with respect to 100 parts by weight of the binder resin. preferable.
The reason for this is that when the added amount of the plurality of electron transfer agents is less than 10 parts by weight, the sensitivity is lowered and a practical problem may occur. On the other hand, when the added amount of the plurality of electron transfer agents exceeds 100 parts by weight, the electron transfer agent is likely to be crystallized, and an appropriate film as a photoreceptor may not be formed.
Therefore, it is more preferable to set the addition amount of the electron transfer agent to a value within the range of 20 to 80 parts by weight.

In addition, when determining the addition amount of an electron transport agent, it is preferable to consider the addition amount of a hole transport agent. More specifically, the addition ratio (total ETM / total HTM) of the electron transport agent (total ETM) is a value within the range of 0.25 to 1.3 with respect to the hole transport agent (total HTM). It is preferable to do.
This is because if the ratio of all ETMs / all HTMs is outside this range, the sensitivity is lowered, which may cause practical problems.
Therefore, it is more preferable that the ratio of the total ETM / total HTM is set to a value within the range of 0.5 to 1.25.

(5) Charge generator (5) -1 type As the charge generator used in the electrophotographic photoreceptor of the present invention, metal-free phthalocyanine (τ type or X type), titanyl phthalocyanine (α type or Y type), It is preferable to include at least one compound selected from the group consisting of hydroxygallium phthalocyanine (type V) and chlorogallium phthalocyanine (type II).
The reason for this is to provide an electrophotographic photosensitive member with more excellent sensitivity characteristics, electrical characteristics, stability, etc. when a hole transporting agent and an electron transporting agent are used in combination by specifying the type of charge generating agent. It is because it can do.

(5) -2 Specific Examples Among these charge generators, it is more preferable to use phthalocyanine pigments (CGM-A to CGM-D) represented by the following formulas (7) to (10). preferable.

  Moreover, it is also preferable to use a conventionally known charge generating agent alone or in combination. Such charge generators include phthalocyanine pigments such as oxo titanyl phthalocyanine, perylene pigments, bisazo pigments, diketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, trisazo pigments, indigo Organic photoconductors such as pigments, azulenium pigments, cyanine pigments, pyrylium pigments, ansanthrone pigments, triphenylmethane pigments, selenium pigments, toluidine pigments, pyrazoline pigments, quinacridone pigments, selenium, selenium-tellurium, selenium- One kind of inorganic photoconductive agent such as arsenic, cadmium sulfide, and amorphous silicon, or a mixture of two or more kinds may be used.

Among the charge generating agents described above, 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, a photosensitive material having sensitivity in a wavelength region of 700 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.

(5) -3 Addition amount The addition amount of the charge generating agent is preferably set to a value within the range of 0.2 to 40 parts by weight with respect to 100 parts by weight of the binder resin.
The reason for this is that when the added amount of the plurality of charge generating agents is less than 0.2 parts by weight, the effect of increasing the quantum yield becomes insufficient, and the sensitivity, electrical characteristics, stability, etc. of the electrophotographic photosensitive member are reduced. This is because it cannot be improved. On the other hand, when the added amount of the plurality of charge generating agents exceeds 40 parts by weight, there is an effect of increasing the extinction coefficient for light having a wavelength in the red region, near infrared region, or infrared region in visible light. This is because the sensitivity characteristics, electrical characteristics, stability, and the like of the photoconductor may not be improved.
Therefore, it is more preferable to set the addition amount of the charge generating agent to a value within the range of 0.5 to 20 parts by weight.

Among the charge generating agents used in the present invention, a compound represented by formula (8) (CGM-
When B) is used, a dispersion aid represented by the following formula (11) (for example, C. IPigment Orange 16) may be added.
This is because the charge generating agent (CGM-B) and the dispersion auxiliary agent (C. IPigment Orange 16) are used together to improve the dispersibility of CGM-B in the coating solution, and the coating solution pot This is because the life can be lengthened.
In addition, when using the dispersion | distribution adjuvant represented by Formula (11), it is preferable to make the addition amount into the value within the range of 30-200 weight part with respect to 100 weight part of all the electric charge generating agents.
The reason for this is that when the amount of the dispersion aid added is less than 30 parts by weight, dispersibility in the coating solution of CGM-B becomes insufficient, and an appropriate film as a photoreceptor cannot be produced. is there. On the other hand, when the dispersion aid exceeds 200 parts by weight, the effect of increasing the quantum yield of the charge generating agent becomes insufficient, and the sensitivity characteristics, electrical characteristics, stability, etc. of the electrophotographic photoreceptor can be improved. It is because it becomes impossible.

(6) Additive In addition to the above-mentioned components, the photoreceptor layer has various conventionally known additives such as an antioxidant, a radical scavenger, a singlet as long as it does not adversely affect the electrophotographic characteristics. Deterioration inhibitors such as quenchers and ultraviolet absorbers, softeners, plasticizers, surface modifiers, extenders, thickeners, dispersion stabilizers, waxes, acceptors, donors, and the like can be blended. In order to improve the sensitivity of the photoreceptor layer, known sensitizers such as terphenyl, halonaphthoquinones, and acenaphthylene may be used in combination with the charge generator.

(7) Structure The thickness of the photoreceptor layer in the single-layer photoreceptor is usually a value in the range of 5 to 100 μm, preferably a value in the range of 10 to 50 μm.
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, etc., plastic materials on which the above metal is vapor-deposited or laminated, glass coated with aluminum iodide, tin oxide, indium oxide, etc., or carbon black Examples thereof include a plastic material obtained by dispersing conductive fine particles.
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. Further, when forming a photoreceptor layer, a binder resin, a hole transport agent, an electron transport agent, and a charge generator, together with an appropriate solvent, for example, a roll mill, a ball mill, an attritor, a paint shaker, What is necessary is just to apply | coat and dry after carrying out dispersion | distribution mixing using a sonic disperser.

  In addition, as shown in FIG. 2B, the barrier layer 16 is formed between the conductive substrate 12 and the photoreceptor layer 14 in a range that does not impair the characteristics of the photoreceptor, as shown in FIG. May be. Further, as shown in FIG. 2C, a protective layer 18 may be formed on the surface of the photoreceptor layer 14.

2. Laminated Photoreceptor (1) Basic Structure As shown in FIG. 3A, the laminated photoreceptor 20 generates a charge containing a charge generating agent on a conductive substrate 12 by means of vapor deposition or coating. A layer 24 is formed, and then a coating solution containing at least one kind of phenanthrenequinone derivative (electron transfer agent) represented by the general formula (1) and a binder resin is applied onto the charge generation layer 24. And the charge transport layer 22 is formed by drying.

In contrast to the above structure, as shown in FIG. 3B, the charge transport layer 22 may be formed on the conductive substrate 12, and the charge generation layer 24 may be formed thereon.
However, since the charge generation layer 24 is much thinner than the charge transport layer 22, for protection, the charge transport layer 22 is formed on the charge generation layer 24 as shown in FIG. It is more preferable to form
The charge generating agent, hole transporting agent, electron transporting agent, binder and the like can be the same as those of the single layer type photoreceptor.

In addition, the layered type photoreceptor is either a positive or negative charge type depending on the order of formation of the charge generation layer and the charge transport layer and the type of charge transport agent (electron transport agent and hole transport agent) used in the charge transport layer. Is selected. For example, when a charge generation layer is formed on a conductive substrate and a charge transport layer is formed thereon, when a hole transport agent such as a stilbene derivative is used as the charge transport agent, the photoreceptor is Negative charge type. In this case, it is also preferable to include an electron transport agent in the charge generation layer. In the case of a multilayer electrophotographic photoreceptor, the residual potential of the photoreceptor is greatly reduced, and the sensitivity can be improved.
Regarding the thickness of the photoreceptor layer in the multilayer photoreceptor, the charge generation layer is about 0.01 to 5 μm, preferably about 0.1 to 3 μm, and the charge transport layer is 2 to 100 μm, preferably 5 to 5 μm. It is about 50 μm.

[Second Embodiment]
The second embodiment is a method for manufacturing the electrophotographic photosensitive member according to the first embodiment.

1. Manufacturing method of single layer type photoreceptor (1) Manufacturing method In forming a single layer type photosensitive layer, a binder resin, a hole transporting agent, an electron transporting agent, and a charge generating agent are added to a solvent. It is preferable to include a step of preparing a coating solution, a step of applying the prepared coating solution on a conductive substrate, and a step of drying the conductive substrate coated with the coating solution.

(2) Coating liquid preparation process A binder resin, a charge generator, an electron transport agent, and a hole transport agent are added to a solvent, for example, a roll mill, a ball mill, an attritor, a paint shaker, an ultrasonic disperser. It is preferable to disperse and mix using a coating solution.
More specifically, it is preferable to prepare a coating solution having a solid content concentration of 10 to 30% by weight. This is because when the solid content concentration of the coating liquid is less than 10% by weight, there is a possibility that a film defect may occur. On the other hand, when the solid content concentration of the coating liquid exceeds 30% by weight, layer unevenness occurs. This is because it tends to occur and it may be difficult to form a thin film having a uniform thickness as a photoreceptor.

Moreover, various organic solvents can be used as the solvent for preparing the coating liquid. 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; dichloromethane, dichloroethane, chloroform and tetrachloride Halogenated hydrocarbons such as carbon and chlorobenzene; ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dioxane and dioxolane; ketones such as acetone, methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate and methyl acetate Class, dimethylformaldehyde, dimethylformamide, dimethylsulfoxide, etc., alone or in combination of two or more. That.
Furthermore, in order to improve the dispersibility of the electron transporting agent, the charge generating agent and the like and the smoothness on the surface of the photoreceptor layer, it is also preferable to add a surfactant, a leveling agent or the like when preparing the coating solution.

(3) Coating process Moreover, when performing a coating process, it is also preferable to apply | coat a coating liquid directly on a conductive base | substrate, or to apply indirectly through a barrier layer.
As a coating method, it is preferable to use, for example, a spin coater, an applicator, a spray coater, a bar coater, a dip coater, a doctor blade, etc., in order to form a photoreceptor layer having a uniform thickness.

(4) Drying process Moreover, after an application | coating process, it is preferable to make it dry at the drying temperature of 60 to 150 degreeC, for example using a high temperature dryer, a vacuum dryer, etc. in a drying process. This is because when the drying temperature is less than 60 ° C., the drying time becomes excessively long, and it may be difficult to efficiently form a photoreceptor layer having a uniform thickness. is there. On the other hand, if the drying temperature exceeds 150 ° C., the photoconductor may be thermally decomposed.

2. Manufacturing Method of Multilayer Photoreceptor (1) Manufacturing Method The manufacturing method of the multilayer photoreceptor layer used in the present invention is also a coating liquid preparation step, a coating step, It is preferable to include a drying step.
The following description will focus on differences from the method for producing a single-layer type photoreceptor.

(2) Coating liquid preparation process The coating liquid of the electrophotographic photosensitive member of the present invention can be prepared similarly to the single-layer type photosensitive member.

(3) Coating process and drying process It is preferable to provide a first coating process and a first drying process, and a second coating process and a second drying process to form a photoreceptor layer composed of a plurality of layers. For example, as shown in FIG. 3A, the charge generation layer 24 is formed on the substrate 12 by the first coating process and the first drying process, and then, by the second coating process and the second drying process, More preferably, the charge transport layer 22 is formed on the charge generation layer 24.
In addition, about the conditions of an application | coating process and a drying process, it can apply according to the manufacturing method of a single layer type photoreceptor.

[Third embodiment]
The third embodiment includes the electrophotographic photosensitive member of the first embodiment (hereinafter sometimes simply referred to as a photosensitive member), and a charging step, an exposure step, and a development around the electrophotographic photosensitive member. An image forming apparatus is characterized in that a process and a transfer process are arranged to form an image. In this example of the image forming apparatus, a case where a single layer type photoreceptor is used as the electrophotographic photoreceptor will be described.

1. Configuration of Image Forming Apparatus (1) In carrying out the image forming method of the third embodiment, a copying machine 30 that is an image forming apparatus as shown in FIG. 4 can be suitably used. The copying machine 30 includes an image forming unit 31, a paper discharge unit 32, an image reading unit 33, and a document feeding unit 34. The image forming unit 31 further includes an image forming unit 31a and a paper feeding unit 31b. In the illustrated example, the document feeding unit 34 includes a document placing tray 34a, a document feeding mechanism 34b, and a document discharge tray 34c, and the document placed on the document placing tray 34a. Is fed to the image reading position P by the document feeding mechanism 34b and then discharged to the document discharge tray 34c.

Then, when the original is sent to the original reading position P, the image reading unit 33 reads the image on the original using the light from the light source 33a. That is, an image signal corresponding to the image on the document is formed using an optical element 33b such as a CCD.
On the other hand, recording sheets (hereinafter simply referred to as “sheets”) S stacked on the sheet feeding unit 31b are sent one by one to the image forming unit 31a. The image forming unit 31a includes a photosensitive drum 41 as an image carrier. Further, around the photosensitive drum 41, a charger 42, an exposure unit 43, a developing unit 44, and a transfer roller. 45 and the cleaning device 46 are arranged along the rotation direction of the photosensitive drum 41.

  Among these components, the photosensitive drum 41 is rotationally driven in the direction indicated by the solid line arrow in the drawing, and the surface thereof is uniformly charged by the charger 42. Thereafter, an exposure process is performed on the photosensitive drum 41 by the exposure device 43 based on the above-described image signal, and an electrostatic latent image is formed on the surface of the photosensitive drum 41. Based on the electrostatic latent image, the developing unit 44 attaches toner and develops it, thereby forming a toner image on the surface of the photosensitive drum 41. The toner image is transferred as a transfer image onto the sheet S conveyed to the nip portion between the photosensitive drum 41 and the transfer roller 45. Next, the sheet S to which the transferred image is transferred is conveyed to the fixing unit 47 and a fixing process is performed.

The paper S after fixing is sent to the paper discharge unit 32. However, when performing post-processing (for example, stapling processing), the paper S is sent to the intermediate tray 32a and then subjected to post-processing. Is called. Thereafter, the sheet S is discharged to a discharge tray portion (not shown) provided on the side surface of the image forming apparatus. On the other hand, when no post-processing is performed, the sheet S is discharged to a discharge tray 32b provided below the intermediate tray 32a. The intermediate tray 32a and the paper discharge tray 32b are configured as a so-called in-body paper discharge unit.
After the transfer is performed as described above, the residual toner (and paper dust) remaining on the photosensitive drum 41 is removed by the cleaning device 46. That is, while the photosensitive drum 41 is cleaned, the residual toner is collected in a waste toner container (not shown).

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.

[Synthesis of Phenanthrenequinone Derivative] The synthesis of the phenanthrenequinone derivative represented by the formula (2) contained in the electrophotographic photosensitive member of the present invention is represented by the following (a) according to the following reaction formula (1). Performed as shown in (c).

  (A) An ether solution of 4-bromo-2,6-di-t-butylphenol represented by the formula (4) is accommodated in a container equipped with a stirrer, and cooled to 0 ° C. while purging with nitrogen. 3 equivalents of a 1.5 mol / liter t-butyllithium pentane solution was added dropwise and stirred for 1 hour. Next, 0.4 equivalent of 9,10-phenanthrenequinone was added and reacted with stirring for 2 hours. The obtained reaction solution was poured into hydrochloric acid water and extracted with chloroform to obtain a phenanthrenequinone derivative represented by the formula (5) (yield 30%).

  (B) After storing the obtained phenanthrenequinone derivative represented by the formula (5) in a container equipped with a stirrer, acetic acid was added to obtain an acetic acid solution. Next, 1.5 equivalents of trifluoroacetic acid was added, and the reaction was allowed to stir at room temperature for 1 hour. The obtained reaction solution was poured into ion-exchanged water to neutralize it, and then extracted with chloroform to obtain a compound represented by the formula (6) (yield 70%).

(C) After the obtained compound represented by the formula (6) was accommodated in a container equipped with a stirrer and a reflux machine, THF was added to obtain a THF solution. Next, 1 equivalent of lithium aluminum hydride was added and reacted while refluxing for 2 hours. The resulting reaction solution was poured into ion exchange water to neutralize it, and then extracted with chloroform to obtain a crude product (yield 80%).
Next, the obtained crude product was dissolved in acetic acid, iodine was further added to a concentration of 0.3% by weight, and the reaction was allowed to reflux for 2 hours. The obtained reaction solution was poured into ion-exchanged water for neutralization, and then extracted with chloroform to obtain a crude product (yield 70%).
Furthermore, after the obtained crude product was dissolved in a benzene solution, 1 equivalent of an aqueous potassium hydroxide solution of potassium ferricyanide was added to cause an oxidation reaction. Subsequently, recrystallization was performed using ethanol to obtain a phenanthrenequinone derivative represented by the formula (2) (yield 90%).

[Example 1]
(1) Preparation of electrophotographic photoreceptor In an ultrasonic dispersing machine, as a charge generator, 3 parts by weight of an X-type metal-free phthalocyanine (CGM-A) represented by formula (7) and a hole transport agent 80 parts by weight of a stilbene derivative (HTM-A) represented by the formula (12) and 40 parts by weight of a phenanthrenequinone derivative (referred to as ETM-A) represented by the formula (2) as an electron transport agent As a binder resin, 100 parts by weight of a copolymer polycarbonate resin (Resin-A) having a viscosity average molecular weight of 50,000 represented by the formula (13) and 800 parts by weight of tetrahydrofuran as a solvent were added. Next, the mixture was dispersed for 1 hour using an ultrasonic disperser to prepare a coating solution for a single-layer type photoreceptor layer. The obtained coating solution is applied on a conductive substrate (aluminum base tube) by dip coating and dried with hot air under conditions of 100 ° C. for 30 minutes, and a single layer type photoreceptor layer having a thickness of 30 μm. An electrophotographic photoreceptor having the following was obtained.

(2) Evaluation The sensitivity characteristics of the obtained electrophotographic photosensitive member were evaluated. That is, the obtained electrophotographic photosensitive member was charged to 700 V using a drum sensitivity tester (manufactured by GENTEC), and then taken out from the light of the halogen lamp using a hand pulse filter, a monochromatic wavelength of 780 nm. Light (half-value width: 20 nm, light amount: 16 μW / cm ² ) was exposed (irradiation time: 80 msec). Then, the surface potential (residual potential) at the time when 330 msec had elapsed from the start of exposure was measured and used as the sensitivity. The obtained results are shown in Table 1.

[Example 2]
In the coating liquid of Example 1, as a charge generating agent, instead of X-type metal-free phthalocyanine (CGM-A) represented by Formula (7), Y-type titanyl phthalocyanine (CGM-) represented by Formula (8) A single-layer photoreceptor was prepared and evaluated in the same manner as in Example 1 except that 3 parts by weight of B)) was added.

[Example 3]
Instead of the phenanthrenequinone derivative represented by the formula (2), the phenanthrenequinone derivative (ETM-B) represented by the formula (3) is used as the electron transport agent in the coating liquid of Example 1. A single layer type photoreceptor was prepared and evaluated in the same manner as in Example 1 except that 40 parts by weight was added.

[Example 4]
Instead of the phenanthrenequinone derivative represented by the formula (2), the phenanthrenequinone derivative (ETM-B) represented by the formula (3) is used as the electron transport agent in the coating liquid of Example 1. 40 parts by weight were added, and instead of the X-type metal-free phthalocyanine (CGM-A) represented by the formula (7), a Y-type titanyl phthalocyanine (CGM-B) represented by the formula (8) was added as a charge generator. A single layer type photoreceptor was prepared and evaluated in the same manner as in Example 1 except that 3 parts by weight was added.

[Comparative Examples 1-3]
Instead of the phenanthrenequinone derivative represented by the formula (2) as an electron transport agent in the coating liquid of Example 1, an electron transport agent represented by the following formulas (14) to (16) (ETM- A single layer type photoreceptor was prepared and evaluated in the same manner as in Example 1 except that 40 parts by weight of C to E) were added.

[Comparative Examples 4 to 6]
In the coating liquid of Example 1, 3 parts by weight of Y-type titanyl phthalocyanine (CGM-B) represented by the formula (8) instead of the X-type metal-free phthalocyanine represented by the formula (7) as a charge generating agent In addition to the phenanthrenequinone derivative represented by the formula (2), 40 electron transport agents (ETM-C to E) represented by the formulas (14) to (16) are added as electron transport agents. A single layer type photoconductor was prepared and evaluated in the same manner as in Example 1 except that parts by weight were added.

As described above in detail, according to the present invention, by using a phenanthrenequinone derivative as an electron transporting agent, an electrophotographic photoreceptor excellent in sensitivity characteristics and an image forming apparatus including the same can be obtained. It became so.
Therefore, the electrophotographic photosensitive member of the present invention is expected to contribute to cost reduction, high speed, high performance, etc. in various image forming apparatuses such as copying machines and printers.

It is an infrared spectroscopy chart of the electron transport agent represented by Formula (2). (A)-(c) is a figure provided in order to demonstrate the basic structure and deformation | transformation structure of a single layer type photoreceptor. (A)-(b) is a figure provided in order to demonstrate the basic structure and deformation | transformation structure of a laminated type photoreceptor. FIG. 3 is a diagram for explaining an image forming apparatus including an electrophotographic photosensitive member.

Explanation of symbols

10: Single layer type photoreceptor 12: Conductive substrate 14: Photoconductor layer 16: Barrier layer 18: Protective layer 20: Multilayer type photoreceptor 22: Charge transport layer 24: Charge generation layer 30: Copying machine
31: Image forming unit 31a: Image forming unit 31b: Paper feeding unit 32: Paper discharge unit 33: Image reading unit 33a: Light source 33b: Optical element 34: Document feeding unit 34a: Document loading tray 34b: Document feeding mechanism 34c: Document discharge tray 41: Photoconductor drum 42: Charger 43: Exposure source 44: Developer 45: Transfer roller 46: Cleaning device

Claims (6)

An electrophotographic photoreceptor comprising a photoreceptor layer containing a binder resin, a hole transport agent, an electron transport agent, and a charge generator,
An electrophotographic photoreceptor comprising a phenanthrenequinone derivative represented by the following general formula (1) as the electron transport agent.

(R ¹ , R ² , R ³ and R ⁴ in the general formula (1) are each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. Group, a substituted or unsubstituted aralkyl group having 6 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms.) ^2. The electrophotographic photosensitive member according to claim 1, wherein R ¹ , R ² , R ³ and R ⁴ in the general formula (1) are a t-butyl group or a methoxy group.   The electrophotographic photosensitive member according to claim 1 or 2, wherein the addition amount of the electron transfer agent is set to a value within a range of 10 to 100 parts by weight with respect to 100 parts by weight of the binder resin.   The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer is a single layer type. In the manufacturing method of the electrophotographic photosensitive member according to any one of claims 1 to 4,
A coating liquid is prepared by mixing and dispersing a binder resin, a hole transport agent, an electron transport agent containing a phenanthrenequinone derivative represented by the following general formula (1), a charge generating agent, and a solvent. And a process of
A step of applying the prepared coating liquid on a conductive substrate;
Drying the conductive substrate coated with the coating solution;
A process for producing an electrophotographic photosensitive member, comprising:

(R ¹ , R ² , R ³ and R ⁴ in the general formula (1) are each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. Group, a substituted or unsubstituted aralkyl group having 6 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms.)   The electrophotographic photosensitive member according to any one of claims 1 to 4 is provided, and a portion for performing a charging step, an exposure step, a developing step, and a transfer step is disposed around the electrophotographic photosensitive member. A featured image forming apparatus.

Images