JP4829625B2 - Electrophotographic photosensitive member and image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member and an image forming apparatus including the same. In particular, the present invention relates to an electrophotographic photosensitive member having excellent sensitivity, wear resistance, stain resistance, and productivity, and an image forming apparatus including the same.

Conventionally, as an electrophotographic photosensitive member used in an image forming apparatus, a charge generating agent for generating charges by light irradiation, a charge transferring agent for transporting the generated charges, and a layer in which these substances are dispersed are used. Organic photoreceptors including a binder resin for forming are widely used.
In producing such an organic photoreceptor, various improvements have been made particularly to its constituent components in order to improve its quality characteristics. For example, a method of using a polycarbonate resin having a relatively large molecular weight as a binder resin or adding a predetermined additive to obtain crack resistance in order to obtain wear resistance that can withstand repeated use. .
However, even when such a method is used, desired image characteristics cannot be obtained, and even if the image characteristics are sufficient, there is a problem that productivity is reduced.

In order to solve such problems, an electrophotographic photoreceptor containing biphenyl as a residual stress reducing agent has been disclosed as a method for improving crack resistance. (For example, see Patent Document 1)
In addition, in order to reduce sensitivity reduction and improve gas resistance, a predetermined polycarbonate resin is used as a binder resin in a photosensitive layer of an electrophotographic photosensitive member, and a biphenyl derivative or a sebacic acid derivative is used as an additive. The electrophotographic photoreceptor used is disclosed. (For example, see Patent Document 2)
Also, a positively charged single layer type electrophotographic photosensitive member using a terphenyl compound as an additive in order to reduce the generation of a transfer memory and improve the gas resistance against NOx, ozone and the like is disclosed. (For example, see Patent Document 3)
Furthermore, an electrophotographic photosensitive member is disclosed in which a predetermined biphenyl derivative is contained as an additive in the photosensitive layer, thereby improving the repeated stability of electric characteristics in positive charging. (For example, see Patent Document 4)
Japanese Patent Laid-Open No. 3-134670 (Claims) JP-A-6-75394 (Claims) JP 2001-242656 A (Claims) JP 2000-314969 A (Claims)

However, all of the electrophotographic photoreceptors disclosed in Patent Documents 1 to 4 have improved crack resistance and repeated stability to some extent, but the sensitivity decreases in the course of repeated use, Along with this, there was a problem that an exposure memory was generated. In addition, when a contamination component from the human body or from the contact member of the photoconductor adheres to the surface of the photoconductor, cracks are generated from that point, and there is a problem that image characteristics are deteriorated.
In addition, the productivity and ease of production when forming the photosensitive layer have not been sufficiently studied.
Thus, as a result of intensive studies, the inventors of the present invention have improved the sensitivity to exposure by containing a hole transport agent having a specific structure together with a plurality of binder resins having different structures, and the entire photosensitive layer. The inventors have found that mechanical characteristics and chemical characteristics can be enhanced and can be easily manufactured, and the present invention has been completed.
That is, an object of the present invention is to provide an electrophotographic photoreceptor excellent in sensitivity, wear resistance, stain resistance, and productivity, and an image forming apparatus including the same.

According to the electrophotographic photoreceptor of the present invention, an electrophotographic photoreceptor comprising a photosensitive layer containing at least a charge generating agent, a hole transporting agent, and a binder resin on a substrate, wherein the binder is a binder. The resin includes a first binder resin and a second binder resin having different structures, and the first binder resin is a polycarbonate resin represented by the following general formula (7), and the second binder The resin is a polycarbonate resin represented by the following general formulas (8) and (9), or a polycarbonate resin represented by either one of the following general formulas (1) to (5): An electrophotographic photoreceptor characterized in that it contains at least one compound represented by the above can solve the above-mentioned problems.

(In General Formula (1), Ra to Re are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a carbon number. 1 to 12 substituted or unsubstituted alkoxy groups, the repeating numbers k, l, n, and p are each independently an integer of 0 to 5, the repeating number m is an integer of 0 to 4, and Except when the repeating numbers k, l, m, n, and p are all 0, Ra and Rb are the above substituents located at the meta position or the para position.

(In General Formula (2), Ra to Rd are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a carbon number. A substituted or unsubstituted alkoxy group having 1 to 12; R ¹ and R ² are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms or a substituted group having 6 to 30 carbon atoms; Or an unsubstituted aryl group, R ¹ may be linked to Rb to form a saturated hydrocarbon ring, and the repeating numbers k, l, and n are each independently an integer of 0 to 5; (The repetition number m is an integer of 0 to 4.)

(In General Formula (3), Ra to Re are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a carbon number. A substituted or unsubstituted alkoxy group having 1 to 12; and R ³ is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. The repeating numbers k, l, n and p are each independently an integer of 0 to 5, the repeating number m is an integer of 0 to 4, and the repeating number q is an integer of 0 or 1.)

(In General Formula (4), Ra to Re are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a carbon number. A substituted or unsubstituted alkoxy group having 1 to 12; R ⁴ and R ⁵ are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted group having 6 to 30 carbon atoms; It is an unsubstituted aryl group, the repeating numbers k, l and m are each independently an integer of 0 to 5, the repeating numbers n and p are integers of 0 to 4, and the repeating numbers r and s are It is an integer of 0 or 1.)

(In General Formula (5), Ra to Rd are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a carbon number. A substituted or unsubstituted alkoxy group having 1 to 12; and R ⁶ is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. The number of repetitions k and n are each independently an integer of 0 to 5, the number of repetitions l and m are integers of 0 to 4, and the number of repetitions t is an integer of 0 or 1.)

(In general formula (7), Ra and Rb are each an independent hydrogen atom, a C1-C4 alkyl group, or a C6-C12 substituted or unsubstituted aryl group, R ⁸ And R ⁹ Are each a different substituent, a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, W is a single bond or —O— or —CO—, and the repeating numbers k to 1 are each independently 0 The number of repetitions m and n is a molar ratio satisfying the relational expression of 0.05 <n / (n + m) <0.6. )

(In the general formula (8), a plurality of substituents Re 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. o is an integer of 0-4.)

(In the general formula (9), the plurality of substituents Rf 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. p is an integer of 0-4.)

That is, by using at least one of the compounds represented by the general formulas (1) to (5) as the hole transport agent, the hole transport efficiency can be improved and excellent sensitivity can be exhibited. Generation of exposure memory can be prevented.
Moreover, the compatibility with the hole transporting agent having a specific structure can be improved by using a first binder resin having a different structure and a second binder resin having different structures as the binder resin. . Therefore, the dispersibility of the hole transport agent having a specific structure in the photosensitive layer is improved, and as a result, the productivity in forming the photosensitive layer can be improved, and further excellent sensitivity can be obtained.

In constituting the electrophotographic photosensitive member of the present invention, the first binder resin has a weight average molecular weight of 40,000 or more, and the second binder resin has a weight average molecular weight of less than 40,000. It is preferable to do.
By comprising in this way, compatibility with the hole transport agent which has a specific structure can be improved more. Therefore, the dispersibility of the hole transport agent having a specific structure in the photosensitive layer can be further improved. Further, it is possible to further improve the balance of contamination resistance and wear resistance in the entire photosensitive layer.

Further, in constituting the electrophotographic photosensitive member of the present invention, the content of the second binder resin having a small weight average molecular weight among the first binder resin and the second binder resin is changed to that of the binder resin. The value is preferably 50% by weight or more based on the total amount.
By configuring in this way, it becomes easier to adjust the stain resistance and wear resistance of the entire photosensitive layer.

Further, in constituting the electrophotographic photoreceptor of the present invention, the first binder resin, characterized in that it comprises a polycarbonate resin represented by the general formula (7), organic and inorganic degree of the polycarbonate resin The value (I / O value) divided by the nature is preferably set to a value of 0.37 or more.
By comprising in this way, dispersibility and stability of the hole transport agent etc. which have a specific structure can be improved. Further, the stain resistance and wear resistance of the photosensitive layer can be further improved.

In constituting the electrophotographic photosensitive member of the present invention, the second binder resin is a polycarbonate resin represented by the general formulas (8) and (9), or a polycarbonate resin represented by any one of the above. It is characterized by including.
By comprising in this way, dispersibility and stability, such as a hole transport agent which has a specific structure, can be improved more. Further, the stain resistance and wear resistance of the photosensitive layer can be further improved.

In constituting the electrophotographic photoreceptor of the present invention, the photosensitive layer preferably contains a compound represented by the following general formula (10) as an additive.
By comprising in this way, a compound (10) acts with respect to the adhesion part of a contaminating component, the generation | occurrence | production of a crack can be suppressed, and the crack generation resulting from a contaminating component can be prevented.

(In General Formula (10), R ^{10 to} R ¹⁹ 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 aralkyl group having 6 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms, a hydroxyl group, A cyano group, a nitro group, or an amino group, R is a substituted or unsubstituted alkylene group having 1 to 12 carbon atoms, or an organic group containing a nitrogen atom, and n represents an integer of 0 to 3).

Further, in constituting the electrophotographic photosensitive member of the present invention, it is preferable that the amount of the additive is set to a value in the range of 1 to 15% by weight with respect to the total solid content of the photosensitive layer.
By comprising in this way, the addition amount of an additive can be adjusted according to the compounding ratio of 1st binder resin and 2nd binder resin in binder resin, and generation | occurrence | production of a crack Further, it can be effectively prevented.
Further, since the glass transition point of the photosensitive layer may decrease as the additive amount increases, the glass transition point can be controlled and the wear resistance can be controlled by controlling the value within such a range. Sex can also be maintained.

Another aspect of the present invention includes any one of the above-described electrophotographic photosensitive members, and a charging unit, an exposing unit, a developing unit, and a transfer unit are arranged around the electrophotographic photosensitive member, and development is performed. An image forming apparatus using a simultaneous development cleaning system as a means.
Here, the simultaneous development cleaning method means a cleaner-less method in which the cleaning device is omitted and the residual toner on the photosensitive member after transfer is collected in the developing device and reused in the developing process.
That is, as described above, the image forming apparatus of the present invention contains a hole transport agent having a specific structure, and thus has excellent sensitivity in the photoreceptor. In addition, since a plurality of binder resins having different structures are used in the photosensitive layer, the photosensitive layer has excellent stain resistance and wear resistance. Therefore, even when such an image forming apparatus is used repeatedly, a residual potential in the photosensitive layer is unlikely to be generated, and it is possible to prevent the residual toner from adhering firmly to the surface of the photosensitive member. Can be omitted.

[First embodiment]
The first embodiment of the present invention is an electrophotographic photosensitive member comprising a photosensitive layer containing at least a charge generating agent, a hole transporting agent, and a binder resin on a substrate, and the binder resin The first binder resin and the second binder resin having different structures are included, and the first binder resin is a polycarbonate resin represented by the general formula (7), and the second binder. The adhesion resin is a polycarbonate resin represented by the above general formulas (8) and (9), or a polycarbonate resin represented by either one , and the above general formulas (1) to ( 1) An electrophotographic photoreceptor comprising at least one compound represented by 5) .
Hereinafter, as a first embodiment of the present invention, a single layer type electrophotographic photosensitive member will be described as an example.

1. Basic Configuration As shown in FIG. 1A, a single-layer type electrophotographic photoreceptor 10 has a single photosensitive layer 14 provided on a substrate 12.
The photosensitive layer 14 is formed by applying a coating solution in which a charge generating agent, an electron transporting agent, a hole transporting agent, a binder resin, and an additive are dissolved or dispersed in a predetermined solvent on the substrate 12. Then, it can be formed by drying.
Such a single-layer type photoreceptor 10 is applicable to both positive and negative charge types, has a simple layer structure, and can suppress film defects when forming a photosensitive layer, so that it has excellent productivity. ing. Moreover, since there are few interfaces between layers, optical characteristics can be improved.
In addition, as illustrated in FIG. 1B, a single-layer type photoreceptor 10 ′ in which an intermediate layer 16 is formed between the photosensitive layer 14 and the substrate 12 may be used.
Further, the thickness of the photosensitive layer 14 is usually a value in the range of 5 to 100 μm, preferably a value in the range of 10 to 50 μm.

2. Substrate As the 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, nickel, Examples thereof include metals such as palladium, indium, stainless steel, and brass, plastic materials on which the above metals are vapor-deposited or laminated, glass coated with aluminum iodide, tin oxide, indium oxide, and the like.
Further, the shape of the substrate may be any of a sheet shape, a drum shape, or the like according to the structure of the image forming apparatus to be used. The substrate itself has conductivity, or the surface of the substrate has conductivity. If you do. Further, the substrate preferably has a sufficient mechanical strength when used. In the case of a drum shape, the diameter of the substrate is preferably 10 to 60 mm, more preferably 10 to 27 mm, from the viewpoint of miniaturization of the apparatus.

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.
Note that when anodization or the like is performed on the substrate, non-conductivity or semiconductor characteristics may be obtained. Even in such a case, the substrate can be used as long as a predetermined effect is obtained.

3. Intermediate Layer Further, as shown in FIG. 1B, an intermediate layer 16 containing a predetermined binder resin may be provided on the substrate 12.
This is because the adhesion between the substrate and the photosensitive layer is improved, and by adding a predetermined fine powder in this intermediate layer, the incident light is scattered to suppress the generation of interference fringes, This is because charge injection from the substrate to the photosensitive layer during non-exposure that causes black spots can be suppressed. The fine powder is not particularly limited as long as it has light scattering properties and dispersibility, and examples thereof include white pigments such as titanium oxide, zinc oxide, zinc white, zinc sulfide, lead white, and lithopone. Inorganic pigments such as alumina, calcium carbonate, barium sulfate and the like, fluorine resin particles, benzoguanamine resin particles, styrene resin particles, and the like can be used.

Moreover, it is preferable to make the film thickness of this intermediate | middle layer into the value within the range of 0.1-50 micrometers. This is because if the intermediate layer is too thick, a residual potential is likely to be generated on the surface of the photoreceptor, which may cause a decrease in electrical characteristics. On the other hand, if the intermediate layer thickness is too thin, the unevenness of the substrate surface cannot be sufficiently relaxed, and the adhesion between the substrate and the photosensitive layer cannot be obtained.
Therefore, the thickness of the intermediate layer is preferably set to a value in the range of 0.1 to 50 μm, and more preferably set to a value in the range of 0.5 to 30 μm.

4). Binder Resin (1) Basic Configuration The binder resin used in the present invention is characterized by including a first binder resin and a second binder resin having different structures.
This is because the use of the first binder resin and the second binder resin having different structures in combination improves the stain resistance selectively exhibited by the first binder resin, and the second binder. This is because a good balance can be achieved between the abrasion resistance selectively exhibited by the resin and the solubility in a solvent and the compatibility with a charge transport agent.
Therefore, the compatibility between the binder resin and the hole transport agent having the specific structure described later in the section of the hole transport agent is improved, and the dispersibility of the hole transport agent having the specific structure in the photosensitive layer is improved. Can be further improved. As a result, the hole transport efficiency is further improved and excellent sensitivity can be exhibited.
The first and second binder resins having different structures can be detected by GPC (gel permeation chromatography) or a difference in solubility. As a method using GPC, there is a method in which the first binder resin and the second binder resin are separated, and the separated binder resins are subjected to structural analysis by NMR or the like. Moreover, the method of utilizing the difference in solubility includes the following methods. When it demonstrates concretely by giving an example, Resin-1 represented by Formula (11) used as 1st binder resin mentioned later is used as 2nd binder resin with respect to the property which does not melt | dissolve in toluene. Since Resin-4 represented by the formula (14) is dissolved in toluene, the photosensitive layer is a solvent in which Resin-1 as the first binder resin and Resin-4 as the second binder resin are dissolved. When the solvent is replaced with toluene after dissolution, Resin-1 as the first binder resin is precipitated, and Resin-4 as the second binder resin is dissolved in toluene. Therefore, Resin-1 as the first binder resin and Resin-4 as the second binder resin are separated and can be analyzed. Further, a method using such a difference in solubility and GPC may be combined and detected.

  Further, as the binder resin, it is preferable to use a first binder resin having a larger weight average molecular weight and a second binder resin having a smaller weight average molecular weight. This is because the properties of each resin can be exhibited more effectively. Therefore, it is possible to more efficiently obtain a photoreceptor excellent in stain resistance and wear resistance.

Here, the role of each resin when a first binder resin having a higher weight average molecular weight and a second binder resin having a lower weight average molecular weight are used as the binder resin will be described. That is, the contamination resistance is selectively improved by the first binder resin because the first binder resin can be packed more densely than the second binder resin. That is, if the resin can be tightly packed, the chemical bonding force of the whole resin is increased, and as a result, the viscosity or hardness is increased and the contamination resistance can be improved.
Further, when contaminating components such as sebum adhere to the surface of the photosensitive layer, the constituent components of the photosensitive layer are eluted into the contaminated component, forming pores in the photosensitive layer and causing cracks. Therefore, when the total amount of the binder resin is composed only of the second binder resin, there is a problem that cracks are likely to occur.
Therefore, these problems can be solved by using the first binder resin and the second binder resin having different weight average molecular weights in combination.
In addition, specific numerical values of the weight average molecular weights of the first binder resin and the second binder resin will be described later.

(2) Blending ratio In addition, the content of the second binder resin having a smaller weight average molecular weight among the first binder resin and the second binder resin is based on the total amount of the binder resin. A value of 50% by weight or more is preferable.
This is because such a blending ratio makes it easy to adjust the stain resistance and wear resistance of the entire photosensitive layer.

(2) -1 Relationship with Crack Resistance Here, FIG. 3 shows the relationship between the content of the first binder resin having a relatively large weight average molecular weight and the crack resistance in the photoreceptor.
In this characteristic diagram, the horizontal axis represents the content (% by weight) relative to the total amount of the first binder resin, and the vertical axis represents the crack generation length (relative value) in the photoreceptor.
As can be understood from the characteristic curve shown in FIG. 3, it can be understood that the crack resistance improves as the value of the content of the first binder resin increases.
However, when the content of the first binder resin is excessively increased, the viscosity of the coating liquid containing the binder resin may be excessively increased. Therefore, in order to adjust the viscosity of the coating solution for forming the photoreceptor layer, it is necessary to add an excess solvent, which may reduce the productivity and economy.
Such a phenomenon is particularly prominent when it is composed only of a high molecular weight binder resin, that is, when the content of the first binder resin is 100 (% by weight) in FIG. Become.
Accordingly, the content of the second binder resin having a smaller weight average molecular weight is preferably set to a value within the range of 50 to 90 (% by weight) with respect to the total amount of the binder resin. A value in the range of (% by weight) is more preferable.

(3) Type The type of the binder resin according to the present invention is not particularly limited. For example, the resin includes a polycarbonate resin, a polyester resin, a polyarylate resin, a styrene-butadiene copolymer, and a 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 Polymers, alkyd resins, polyamides, polyurethanes, polysulfones, diallyl phthalate resins, ketone resins, polyvinyl butyral resins, polyether resins, and other thermoplastic resins, silicone resins, epoxy resins, phenol resins, urea resins, melamine resins, and other crosslinks of Curable resin, epoxy acrylate, urethane - resin such as photocurable resin such as acrylate can be used.

Further, in constituting the photoreceptor of the present invention, the binder resin includes the polycarbonate resin represented by the general formula (7) described above as the first binder resin .
This is because the polycarbonate resin having such a structure can further improve the stain resistance in the photosensitive layer.
That is, since the polycarbonate resin having such a structure is excellent in stain resistance particularly in the photosensitive layer, the balance between the wear resistance and stain resistance in the photosensitive layer is preferably within a suitable range by using in combination with other resins. This is because it is easy to adjust inward.

Moreover, it is preferable to make the value (I / O value) which divided the inorganic degree in the 1st binder resin represented by General formula (7) mentioned above by the organic degree into the value of 0.37 or more.
The reason is that the dispersibility and stability of the hole transport agent and the electron transport agent having a specific structure are improved by setting the I / O value in the first binder resin to a value of 0.37 or more. Because. Therefore, the occurrence of cracks is further reduced by repeated use of a long-term feeling or adhesion of finger oil, and also suppresses crystallization of a hole transport agent or the like in the photosensitive layer, thereby making charge transport more efficient. be able to.
However, when the I / O value in the first binder resin is excessively large, the miscibility with a hole transporting agent or an electron transporting agent having a specific structure may be lowered.
Therefore, the I / O value of the first binder resin is more preferably set to a value within the range of 0.375 to 1.7, and further preferably set to a value within the range of 0.38 to 1.6. preferable.
In addition, it is preferable to make the I / O value in the second binder resin represented by the general formulas (8) to (9) described above a value less than 0.37.
This is because the I / O value in the second binder resin is less than 0.37, so that the above-mentioned I / O value is 0.37 or more. This is because the properties of the binder resin when used together can be easily adjusted.

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 a value obtained by quantifying the magnitude of the influence on the boiling point of various substituents and bonds of an organic compound, 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.

In constituting the electrophotographic photosensitive member of the present invention, the second binder resin is the polycarbonate resin represented by the general formula (8) and the general formula (9) described above, or the polycarbonate resin represented on the other hand. It is characterized by including .
This is because a polycarbonate resin having such a structure not only improves the compatibility with the hole transport agent having a specific structure, but can further improve the abrasion resistance in the photosensitive layer. is there.
That is, if it is a polycarbonate resin which has such a structure, the balance among the sensitivity in a photosensitive layer, abrasion resistance, stain resistance, etc. can be adjusted more suitably.

(4) Specific example Moreover, as a specific example of 1st polycarbonate resin represented by General formula (7) mentioned above, polycarbonate resin (Resin-1-3) represented by following formula (11)-(13). ).

  Specific examples of the second polycarbonate resin represented by the general formulas (8) to (9) described above are polycarbonate resins (Resin-4 to 5) represented by the following formulas (14) to (15), respectively. ).

  Moreover, as polycarbonate resin other than general formula (7)-(9), the polycarbonate resin (Resin-6) represented by following formula (16) is mentioned.

(5) Weight average molecular weight The weight average molecular weight of the first binder resin and the second binder resin is not particularly limited. For example, the weight average molecular weight of the first binder resin is 40, The weight average molecular weight of the second binder resin is preferably less than 40,000.
The reason for this is to increase the solubility of the first binder resin and the second binder resin, respectively, and further improve the compatibility with the hole transport agent having a specific structure. Because it can. As a result, the dispersibility of the hole transport agent having a specific structure in the photosensitive layer can be further improved. Moreover, it is because the balance of the stain resistance and the wear resistance in the entire photosensitive layer can be further improved.
However, when the weight average molecular weight of the first binder resin is relatively large and the weight average molecular weight of the second binder resin becomes too small, the first binder resin is excessively affected. , Viscosity and hardness become excessively high.
Conversely, when the weight average molecular weight of the first binder resin is relatively small and the weight average molecular weight of the second binder resin is relatively large, that is, the difference between the weight average molecular weights of both is extremely small. Then, there arises a problem that the effect of using a plurality of binder resins having different weight average molecular weights is reduced.

Therefore, as the range of the weight average molecular weight, the weight average molecular weight of the first binder resin is set to a value within the range of 40,000 to 60,000, and the weight average molecular weight of the second binder resin is 10,000. It is more preferable to set the value within a range of ˜30,000.
Further, the weight average molecular weight of the first binder resin is set to a value within the range of 45,000 to 50,000, while the weight average molecular weight of the second binder resin is within the range of 15,000 to 25,000. More preferably, the value is within the range.
The weight average molecular weights of the first binder resin and the second binder resin can be measured using GPC or Ostwald viscometer.

5). Charge generator In addition, examples of the charge generator in the present invention include phthalocyanine pigments such as metal-free phthalocyanine and oxotitanyl phthalocyanine, perylene pigments, bisazo pigments, diketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, and metal naphthalocyanine pigments. Organic photoconductivity such as phthalocyanine pigment, squaraine pigment, trisazo pigment, indigo pigment, azurenium pigment, cyanine pigment, pyrylium pigment, ansanthrone pigment, triphenylmethane pigment, selenium pigment, toluidine pigment, pyrazoline pigment, quinacridone pigment And conventionally known charge generating agents such as inorganic photoconductive materials such as selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, and amorphous silicon can be used.

More specifically, it is more preferable to use phthalocyanine pigments (CGM-A to CGM-D) represented by the following formulas (17) to (20).
This is because a photoreceptor having sensitivity in a wavelength region of 600 to 800 nm or more is required when used in a digital optical image forming apparatus such as a laser beam printer or a facsimile provided with a semiconductor laser as a light source. It is.
On the other hand, when used in an analog optical image forming apparatus such as an electrostatic copying machine having a white light source such as a halogen lamp, a photosensitive member having sensitivity in the visible region is required. Perylene pigments and bisazo pigments can be preferably used.

6). Hole transport agent The hole transport agent used in the present invention is characterized by using at least one of the compounds represented by the general formulas (1) to (5) described above.
This is because, by using the compounds represented by the general formulas (1) to (5) as the hole transporting agent, it exhibits excellent sensitivity in combination with the compatibility with the binder resin described above. It is because it can do.
That is, by setting the compatibility between the compounds represented by the general formulas (1) to (5) and a plurality of resins having different structures as the binder resin to a suitable state, the general formulas (1) to (5 ) This is because the excellent hole transport ability possessed by the compound represented by ) can be effectively exhibited. In other words, since the dispersibility of the hole transport agent having a specific structure is improved in the photosensitive layer, the charge transport becomes efficient, can exhibit excellent sensitivity, and effectively prevents the occurrence of exposure memory. It can be done.

(1) Specific Example Moreover, as a specific example of the hole-transporting agent represented by the general formula (1), compounds represented by the following formulas (21) to (22) (HTM-1 to 2) may be mentioned. .

  Specific examples of the hole transporting agent represented by the general formula (2) include compounds (HTM-3 to 6) represented by the following formulas (23) to (26).

  Specific examples of the hole transporting agent represented by the general formula (3) include compounds (HTM-7 to 8) represented by the following formulas (27) to (28).

  Specific examples of the hole transport agent represented by the general formula (4) include compounds (HTM-9 to 11) represented by the following formulas (29) to (31).

  Specific examples of the hole transporting agent represented by the general formula (5) include compounds represented by the following formulas (32) to (33) (HTM-12 to 13).

(2) Addition amount The addition amount of the hole transport agent is preferably set to a value within the range of 1 to 120 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 hole transport ability of the photosensitive layer is extremely lowered, which may adversely affect image characteristics.
Further, when the added amount exceeds 120 parts by weight, there is a problem that dispersibility is lowered and crystallization is easily caused.
Therefore, the amount of the hole transporting agent added is preferably 5 to 100 parts by weight, preferably 10 to 90 parts by weight with respect to 100 parts by weight of the binder resin. Is more preferable.

(3) Molecular weight Moreover, it is preferable to make the molecular weight of a hole transport agent into the value within the range of 180-2000.
This is because when the molecular weight of the hole transport agent is less than 180, the hole transport agent is likely to be eluted when a contaminating component adheres to the surface of the photoreceptor.
On the other hand, when the molecular weight of the hole transport agent exceeds 2000, elution into the contaminating component can be suppressed, but the dispersibility in the photosensitive layer is decreased or the hole transport ability is decreased. This is because there is a risk of being lost.
Therefore, the molecular weight of the hole transport agent is preferably set to a value within the range of 200 to 1800, and more preferably set to a value within the range of 300 to 1500.
As the molecular weight of the hole transport agent, a value calculated based on the structural formula may be used, or a measured value in a mass spectrum may be used.

7). Additive In the present invention, the photosensitive layer preferably contains the compound represented by the general formula (10) described above as an additive.
The reason for this is that when a contaminating component adheres to the surface of the photoreceptor and the monomer component elutes and pores are formed inside the photosensitive layer, the general formula (10) as an additive is added to the pores. This is because the compound represented acts to release local stress and suppress the generation of cracks.
Therefore, the stain resistance exhibited using the binder resin as described above can be more effectively exhibited, and stable image characteristics can be maintained.
In addition, when making R in General formula (10) into the organic group containing a nitrogen atom, it can be set as the organic group represented by following formula (37), for example.

(1) Specific example Moreover, as a specific example of an additive, the compound (BP-1-5) represented by following formula (38)-(42) is mentioned.

(2) Addition amount The addition amount of the additive in the present invention is preferably set to a value in the range of 1 to 15% by weight relative to the total amount of solid content of the photosensitive layer.
The reason for this is that when the added amount is less than 1% by weight, the stress relaxation action as described above cannot be sufficiently exhibited, and cracks cannot be sufficiently prevented.
On the other hand, if the addition amount exceeds 15% by weight, the glass transition point of the photosensitive layer is lowered, and the wear resistance may be lowered. Moreover, it is because the dispersibility in binder resin falls and the case where it crystallizes is seen.
That is, when the addition amount is a value within such a range, the wear resistance and contamination resistance of the photosensitive layer can be obtained without excessively increasing the molecular weight of the binder resin. A photoconductor excellent in productivity can be obtained.

Therefore, the range of the addition amount is preferably 2 to 12% by weight, and more preferably 3 to 10% by weight with respect to the total amount of the solid content of the photosensitive layer.
The total amount of the solid content of the photosensitive layer means the addition ratio of the constituent components of the photosensitive layer excluding the solvent, and in the present invention, a charge generating agent, a charge transporting agent, a binder resin, This means the addition ratio of the additive and the additive.

(3) Molecular weight Moreover, it is preferable to make the molecular weight of this additive into the value within the range of 100-350.
This is because when the molecular weight of such an additive is less than 100, the stress in the vicinity of the vacancies may not be released sufficiently.
Conversely, when the molecular weight of the additive exceeds 350, the dispersibility in the binder resin is lowered, and the interaction with the pores cannot be sufficiently exhibited.
Therefore, the molecular weight range of the additive is preferably set to a value within the range of 150 to 300, and more preferably set to a value within the range of 180 to 270.
The molecular weight of the additive can be calculated based on, for example, the structural formula, or can be measured using a mass spectrum obtained with a mass spectrometer.

8). Electron transport agent The electron transport agent used in the present invention is not particularly limited. For example, benzoquinone compounds, naphthoquinone compounds, anthraquinone compounds, diphenoquinone compounds, dinaphthoquinone compounds, naphthalenetetracarboxylic acid. Diimide compounds, fluorenone compounds, malononitrile compounds, thiopyran compounds, trinitrothioxanthone compounds, dinitroanthracene compounds, dinitroacridine compounds, nitroantharaquinone compounds, dinitroanthraquinone compounds, one or more The combination of these is mentioned.

  Specific examples of the electron transfer agent include compounds (ETM-1 to 4) represented by the following formulas (43) to (46).

9. The glass transition point of the photosensitive layer The glass transition point (Tg) of the photosensitive layer is preferably set to a value of 60 ° C. or higher.
This is because, as described above, when an additive is contained, the glass transition point of the photosensitive layer changes, which may affect the wear resistance.
That is, if the additive is excessively contained and the glass transition point is set to a predetermined value or less, the pressure resistance is lowered and the image characteristics may be adversely affected when used repeatedly. On the other hand, if the glass transition point becomes too high, the surface of the photoreceptor is excessively cured, and there is a problem that cracks are likely to occur.
Therefore, the value of the glass transition point (Tg) is preferably set to a value within the range of 60 to 90 ° C, and more preferably set to a value within the range of 65 to 80 ° C.

In addition, a glass transition point can be calculated | required from the change point of a specific heat using a differential scanning calorimeter (DSC). As a measuring apparatus, it can obtain | require by measuring an endothermic curve, for example using differential scanning calorimeter DSC-6200 (made by Seiko Instruments Inc.).
More specifically, 10 mg of a measurement sample composed of a charge generating agent, an electron transport agent, a hole transport agent, an additive, and a binder resin, which are materials constituting the photoconductor, is placed in an aluminum pan and empty as a reference. Using an aluminum pan, the glass transition point can be obtained from the change point of the endothermic curve obtained by measuring at a temperature range of 25 to 200 ° C. and a temperature increase rate of 10 ° C./min under normal temperature and humidity.

10. Production Method The production method of the electrophotographic photosensitive member is not particularly limited, but can be carried out by the following procedure.
First, a coating solution is prepared by adding a charge generating agent, a charge transporting agent, a binder resin, an additive and the like to a solvent. The coating solution thus obtained is applied onto a conductive substrate (aluminum tube) using 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. Apply.
Thereafter, as an example, a single layer type electrophotographic photosensitive member having a photosensitive layer having a predetermined thickness can be obtained by drying with hot air at 100 ° C. for 30 minutes.

  In addition, as a solvent for making 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, 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. At this time, in order to improve the dispersibility of the charge generating agent and the smoothness of the surface of the photoreceptor layer, a surfactant, a leveling agent and the like may be added.

It is also preferable to form an intermediate layer on the conductive substrate before forming this photosensitive layer.
In forming this 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, ball mill, attritor, paint shaker, ultrasonic wave A coating solution is prepared by dispersing and mixing using a disperser or the like, and this is applied by a known means such as a blade method, a dipping method, or a spray method, and subjected to heat treatment to form an intermediate layer.
In addition, the additive is in a range where sedimentation at the time of manufacture does not become a problem, causing light scattering to prevent generation of interference fringes, maintaining an appropriate resistance value between the substrate and the photosensitive layer, etc. For the purpose, various additives (organic fine powder or inorganic fine powder) can be added in small amounts.
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 can apply | coat using the apply | coating method.
Then, it is preferable to perform the process of drying the coating liquid on a support base in the range of 5 minutes-2 hours at the temperature of 20-200 degreeC.

  As the solvent for preparing such a coating solution, various organic solvents can be used as in the case of forming the photosensitive layer, for example, alcohols such as methanol, ethanol, isopropanol, and butanol; n-hexane, octane, cyclohexane and other aliphatic hydrocarbons; benzene, toluene, xylene and other aromatic hydrocarbons, dichloromethane, dichloroethane, chloroform, carbon tetrachloride, chlorobenzene and other halogenated hydrocarbons; acetone, methyl ethyl ketone, Ketones such as cyclohexanone; esters such as ethyl acetate and methyl acetate; dimethylformaldehyde, dimethylformamide, dimethylsulfoxide and the like. These solvents are used alone or in admixture of two or more.

11. Others As described above, the electrophotographic photosensitive member of the present invention is preferably used for a single-layer type electrophotographic photosensitive member, but it is also preferable to use a laminated electrophotographic photosensitive member as shown in FIG.
In this multilayer photoconductor 20, a charge generation layer 24 containing a charge generation agent is formed on the substrate 12 by means of vapor deposition or coating, and then a charge transport agent is bound on the charge generation layer 24. The charge transporting layer 22 can be formed by applying a coating solution containing a resin and drying it.
In contrast to the above structure, as shown in FIG. 2B, the charge transport layer 22 may be formed on the 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
Furthermore, the intermediate layer 25 may be formed on the conductive substrate as in the case of the single-layer type photoreceptor.

In manufacturing such a multilayer electrophotographic photosensitive member, the charge generation layer forming coating solution and the charge transport layer forming coating solution are respectively adjusted. That is, for example, a predetermined component such as a charge generator, a charge transport agent, and a binder resin is prepared by dispersing and mixing together with a dispersion medium using a roll mill, ball mill, attritor, paint shaker, ultrasonic disperser, or the like. can do.
In addition, in the photosensitive layer 20 of such a laminated electrophotographic photosensitive member, the thickness of the charge generation layer is preferably set to a value within the range of 0.01 to 5 μm, more preferably 0.1 to 3 μm. The value is within the range. Similarly, the charge transport layer is preferably set to a value within the range of 2 to 100 μm, more preferably set to a value within the range of 5 to 50 μm.

[Second Embodiment]
The second embodiment includes the electrophotographic photosensitive member of the first embodiment, and a portion for carrying out a charging unit, an exposure unit, a developing unit, and a transfer unit is disposed around the electrophotographic photosensitive member. In addition, the image forming apparatus is characterized in that a simultaneous development cleaning system is used as the developing means.

That is, as shown in FIG. 4, around the photosensitive member 31, a charger 32 as a charging unit, an exposure light source 33 as an exposure unit, a developing unit 34 as a developing unit, and a transfer unit as a transfer unit. 35 are sequentially arranged.
The photoconductor 31 rotates at a constant speed in the direction of the arrow, and the electrophotographic process is performed on the surface of the photoconductor 31 in the following order. More specifically, the photosensitive member 31 is entirely charged by the charger 32, and then the print pattern is exposed by the exposure light source 33.

Next, the developing device 34 develops toner corresponding to the print pattern, and the transfer device 35 further transfers the toner to a transfer material (paper) 36.
Here, the developer 34a in which the toner is dispersed is conveyed by the developing roller 34b, and the toner is attracted onto the surface of the photoconductor 31 by applying a predetermined developing bias, and developed on the photoconductor 31. Will be. At the same time, the toner moves due to the potential difference between the unexposed potential of the photoreceptor 31 and the developing bias, and the remaining toner is collected.
Therefore, when the electrophotographic photosensitive member of the present invention is used as the photosensitive member 31, the first binder resin and the second binder resin having different structures are blended and used at predetermined contents, respectively. By using a hole transporting agent having a specific structure, not only is it excellent in sensitivity, but also excellent in stain resistance and abrasion resistance, even when adopting the development simultaneous cleaning method in which the cleaning device is omitted, Predetermined image characteristics can be stably maintained.
The electrophotographic photosensitive member can have the same contents as in the first embodiment.

[Example 1]
1. Preparation of multilayer electrophotographic photoreceptor (1) Formation of undercoat layer Titanium oxide surface treated with methyl hydrogen polysiloxane after wet-dispersed surface treatment with alumina and silica using a bead mill (Taika Co., Ltd.) Manufactured, SMT-02 (number average primary particle size: 10 nm) 2.5 parts by weight and 6,12,66,610 quaternary copolymerized polyamide resin (manufactured by Toray Industries, Inc., Amilan CM8000) 1 part by weight, Dispersed together with 10 parts by weight of methanol and 2.5 parts by weight of butanol for 5 hours to prepare an undercoat layer coating solution.
Next, after filtering the obtained coating solution for the undercoat layer with a 5 micron filter, a dip coating method was applied to an aluminum drum-shaped support having a diameter of 30 mm and a total length of 238.5 mm as a conductive support. And an undercoat layer having a film thickness of 2 μm was formed by heat treatment at 130 ° C. for 30 minutes.

(2) Formation of photosensitive layer Using bead mill, 2 parts by weight of titanyl phthalocyanine (CGM-B) represented by the formula (18) produced by the production method shown below as a charge generating agent, polyvinyl as a binder resin 1 part by weight of butyral resin (Denka Butyral # 6000EP Denki Kagaku Kogyo) was dispersed for 2 hours with 40 parts by weight of propylene glycol monomethyl ether and 40 parts by weight of tetrahydrofuran as a dispersion medium to prepare a coating solution for charge generation layer.
The obtained coating solution for charge generation layer was filtered through a 3 micron filter, and then applied by dip coating on a drum-like support on which an undercoat layer had been formed, under conditions of 80 ° C. for 5 minutes. Heat treatment was performed to form a charge generation layer having a thickness of 0.2 μm.
Next, similarly, using a bead mill, 70 parts by weight of the compound (HTM-1) represented by the formula (21) as a hole transport agent and metaterphenyl represented by the formula (38) as an additive (BP-1) 5 parts by weight, as a binder resin, 30 parts by weight of a polycarbonate resin (Resin-1, IO value: 0.385) represented by the formula (11) having a viscosity average molecular weight of 50,000, and a viscosity average 70 parts by weight of a polycarbonate resin (Resin-4) represented by the formula (14) having a molecular weight of 20,000 and 610 parts by weight of tetrahydrofuran as a solvent were mixed and dissolved to prepare a coating solution for a charge transport layer.
The obtained charge transport layer coating solution was applied onto a drum-like support on which the charge generation layer was formed in the same manner as the charge generation layer coating solution, and heat-treated at 120 ° C. for 30 minutes. A charge transport layer having a thickness of 20 μm was formed to obtain a multilayer electrophotographic photosensitive member of Example 1.

Moreover, manufacture of the titanyl phthalocyanine (CGM-B) represented by Formula (18) used in Example 1 was implemented as follows.
(1) Production of titanyl phthalocyanine compound In an argon-substituted flask, 25 g of o-phthalonitrile, 28 g of titanium tetrabutoxide, 20 g of urea, and 300 g of quinoline were added, and the temperature was raised to 150 ° C while stirring.
Next, after 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.

(2) Pre-pigmentation treatment After completion of the reaction, when the reaction mixture was cooled to 150 ° C, the reaction mixture was taken out of the flask, filtered through a glass filter, and the resulting solid was washed successively with N, N-dimethylformamide and methanol. Thereafter, it was vacuum-dried to obtain 25 g of a blue-violet solid.
Next, 15 g of the obtained blue-violet solid was added to 100 ml of N, N-dimethylformamide, heated to 130 ° C., and stirred for 2 hours.
Next, when 2 hours had passed, heating was stopped, the system was cooled to 23 ± 1 ° C., and stirring was also stopped.
The stabilized liquid was filtered off 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 titanyl phthalocyanine.

(3) Pigmentation treatment Next, 5 g of crude crystals of titanyl phthalocyanine obtained by the pigmentation pretreatment were added to 100 ml of concentrated sulfuric acid and dissolved.
Next, this solution was dropped into ice-cooled water, stirred at room temperature for 15 minutes, and further allowed to stand at about 23 ± 1 ° C. for 30 minutes for recrystallization.
Next, the crystals are separated by a glass filter, and the obtained solid is washed with water until the washing solution becomes neutral, and then dispersed in 200 ml of chlorobenzene in a state where water is present without drying, and 50 ° C. And stirred for 10 hours.
Further, after being separated by a glass filter, the obtained solid was vacuum-dried at 50 ° C. for 5 hours to obtain 4.5 g of titanyl phthalocyanine crystals (blue powder).
The obtained titanyl phthalocyanine has 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 that there was a single peak at 302 ° C. in addition to the peak near 90 ° C. accompanying vaporization of adsorbed water when the temperature was raised to 400 ° C. in the differential calorimetry.

2. Evaluation of electrophotographic photosensitive member (1) Bright potential evaluation The obtained electrophotographic photosensitive member was mounted on a commercially available printer (Okidata Co., Ltd., MicroLine-18) employing a negative charge reversal development process. The light potential was evaluated in an / N environment (25 ° C., 50% Rh). That is, the electrophotographic photosensitive member was initially charged so as to have a potential of −850 to −900 V, a black solid image was formed, and the bright potential at the development position at that time was measured as the reading sensitivity.

(2) Wear resistance evaluation The obtained electrophotographic photosensitive member was mounted on the above-described printer (MicroLine-18), and 10,000 sheets were continuously printed. Then, the film thickness before and after printing was measured with an eddy current film thickness meter, and the change in film thickness was used as a rough film thickness as a measure of wear resistance.

(3) Evaluation of oil resistance The oil resistance of the obtained electrophotographic photosensitive member was evaluated. That is, the entire surface of the electrophotographic photosensitive member was touched with a hand to attach sufficient oil and fat, and then allowed to stand for 48 hours. Next, a gray image was formed by the above-described printer (MicroLine-18) equipped with this electrophotographic photosensitive member, and the presence or absence of image defects due to cracks was visually observed. And oil resistance evaluation was implemented along the following references | standards.
A: The number of occurrences of cracks is zero in an area corresponding to one round of the drum.
○: The number of occurrences of cracks is 1 to 10 in an area corresponding to one round of the drum.
(Triangle | delta): The number of crack generations is 11-20 in the area | region for 1 round of drums.
X: The number of crack occurrences is 21 or more in an area corresponding to one round of the drum.

[Examples 2 to 18, Reference Examples 19 to 22 ]
In Examples 2 to 18 and Reference Examples 19 to 22 , the effect of the combination of a plurality of binder resins and the type of hole transport agent combined with the plurality of binder resins was examined. That is, as shown in Table 1, an electrophotographic photoreceptor was prepared and evaluated according to Example 1 except that the composition of the electrophotographic photoreceptor was changed. The obtained results are shown in Table 1.

[Comparative Examples 1 to 10]
In Comparative Examples 1 to 10, as shown in Table 1, an electrophotographic photoreceptor was prepared and evaluated according to Example 1 except that the composition of the electrophotographic photoreceptor was changed. The obtained results are shown in Table 1.
In addition, the positive hole transport agent used in Comparative Examples 7-10 is a compound (HTM-17-20) represented by following formula (47)-(50), respectively.

[Example 23]
1. Production of Single Layer Type Electrophotographic Photoreceptor (1) Formation of Undercoat Layer Similar to Example 1, film thickness was measured on an aluminum drum-shaped support having a diameter of 30 mm and a total length of 238.5 mm as a conductive support. A subbing layer of 2 μm was formed.

(2) Formation of photosensitive layer Using an ultrasonic disperser, as a binder resin, 30 parts by weight of a polycarbonate resin (Resin-1) represented by the formula (11) having a viscosity average molecular weight of 50,000, a viscosity average molecular weight of 20 70 parts by weight of a polycarbonate resin (Resin-4) represented by the formula (14) of 1,000, X-type metal-free phthalocyanine (CGM-A) represented by the formula (17) (Fastgen, manufactured by Dainippon Ink Co., Ltd.) 3 parts by weight of Blue 8120BS), 50 parts by weight of the hole transport agent (HTM-1) represented by formula (21), 30 parts by weight of the electron transport agent (ETM-1) represented by formula (43), and dimethyl 0.1 parts by weight of silicon oil (manufactured by Shin-Etsu Chemical Co., Ltd., KF-96-50CS) and 760 parts by weight of tetrahydrofuran as a dispersion medium were mixed and dispersed.
The obtained photosensitive layer forming coating solution is applied onto a drum-like support on which an undercoat layer is formed, heat-treated at 120 ° C. for 30 minutes, and charge transport with a film thickness of 28 μm using a ring coating method. A single layer type electrophotographic photoreceptor of Example 23 was formed.

2. Evaluation of Single Layer Type Electrophotographic Photoreceptor The obtained single layer type electrophotographic photosensitive member is mounted on a commercially available copying machine (manufactured by Kyocera Mita, KM-4530) adopting a positive charge reversal development process. In addition, electrical characteristics (sensitivity), wear resistance, and oil resistance were evaluated.
That is, in measuring the electrical characteristics, the grid potential was adjusted so that the charge amount was 650 V, and the bright potential at the development position when the black solid image was formed was measured as the reading sensitivity.
Also, the obtained single-layer type electrophotographic photosensitive member is mounted on a copying machine (Kyocera Mita, KM-4530), and A1 side 15,000 copies are made in a single shot, and the film thickness before and after copying is scraped off. The film thickness was measured with an eddy current film thickness meter, and used as a measure of wear resistance.
Furthermore, the oil resistance was evaluated by the same method as in Example 1 except that a commercially available copying machine (Kyocera Mita, KM-4530) was used.

[Examples 24-38, 42-44, Reference Examples 39-41 ]
In Examples 24-38, 42-44, and Reference Examples 39-41, as shown in Table 2, electrons were changed in the same manner as in Example 23 except that the type of hole transport agent and the type of electron transport agent were changed. Photoconductors were prepared and evaluated. The obtained results are shown in Table 2.

[Example 45]
In Example 45, an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 23 except that titanyl phthalocyanine (CGM-B) represented by the formula (18) was used as the charge generator. The obtained results are shown in Table 2.

[Comparative Examples 11 to 16]
In Comparative Examples 11 to 16, as shown in Table 2, an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 23 except that the type of hole transport agent and the type of electron transport agent were changed. . The obtained results are shown in Table 2.

According to the electrophotographic photoreceptor of the present invention, by containing a hole transporting agent having a specific structure together with a plurality of binder resins (first binder resin and second binder resin) having different structures. In addition to improving the sensitivity to exposure, the mechanical characteristics and chemical characteristics of the entire photosensitive layer can be improved, and further, it can be easily manufactured.
That is, not only the sensitivity is excellent, but also the wear resistance, stain resistance, and productivity are excellent, and good image characteristics can be maintained over a long period of time.
Therefore, the electrophotographic photosensitive member of the present invention is expected to contribute to high durability, long life, high image quality, etc. in various image forming apparatuses such as copying machines and printers.

1 is a cross-sectional view showing a single layer type photoreceptor according to the present invention. 1 is a cross-sectional view showing a multilayer photoreceptor according to the present invention. It is a characteristic view which shows the relationship between content of 1st binder resin, and crack resistance. 1 is a schematic diagram illustrating an example of an image forming apparatus according to the present invention.

Explanation of symbols

10: Single layer type photoreceptor, 12: Conductive substrate, 14: Photosensitive layer, 16: Intermediate layer, 20: Multilayer type photoreceptor, 22: Charge transport layer, 24: Charge generation layer, 25: Intermediate layer, 31: Photoconductor, 32: charger, 33: exposure light source, 34: developing device, 35: transfer device, 36: transfer paper

Claims (7)

An electrophotographic photoreceptor comprising a photosensitive layer containing at least a charge generating agent, a hole transporting agent, and a binder resin on a substrate,
As the binder resin, including a first binder resin and a second binder resin having different structures,
The first binder resin is a polycarbonate resin represented by the following general formula (7),
The second binder resin is a polycarbonate resin represented by the following general formulas (8) and (9), or a polycarbonate resin represented by one of the following:
An electrophotographic photosensitive member comprising at least one compound represented by the following general formulas (1) to (5) as the hole transport agent.

(In General Formula (1), Ra to Re are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a carbon number. 1 to 12 substituted or unsubstituted alkoxy groups, the repeating numbers k, l, n, and p are each independently an integer of 0 to 5, the repeating number m is an integer of 0 to 4, and Except when the repeating numbers k, l, m, n, and p are all 0, Ra and Rb are the above substituents located at the meta position or the para position.

(In General Formula (2), Ra to Rd are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a carbon number. A substituted or unsubstituted alkoxy group having 1 to 12, R ¹ and R ² are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted group having 6 to 30 carbon atoms; An unsubstituted aryl group, R ¹ may be linked to Rb to form a saturated hydrocarbon ring, and the repeating numbers k, l, and n are each independently an integer of 0 to 5; The number m is an integer from 0 to 4.)

(In General Formula (3), Ra to Re are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a carbon number. A substituted or unsubstituted alkoxy group having 1 to 12; and R ³ is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. The repeating numbers k, l, n and p are each independently an integer of 0 to 5, the repeating number m is an integer of 0 to 4, and the repeating number q is an integer of 0 or 1.)

(In General Formula (4), Ra to Re are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a carbon number. A substituted or unsubstituted alkoxy group having 1 to 12; R ⁴ and R ⁵ are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted group having 6 to 30 carbon atoms; It is an unsubstituted aryl group, the repeating numbers k, l and m are each independently an integer of 0 to 5, the repeating numbers n and p are integers of 0 to 4, and the repeating numbers r and s are It is an integer of 0 or 1.)

(In General Formula (5), Ra to Rd are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a carbon number. A substituted or unsubstituted alkoxy group having 1 to 12; and R ⁶ is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. The number of repetitions k and n are each independently an integer of 0 to 5, the number of repetitions l and m are integers of 0 to 4, and the number of repetitions t is an integer of 0 or 1.)
(In the general formula (7), Ra and Rb 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 R ⁸ and R ⁹ Are each a different substituent, a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, W is a single bond or —O— or —CO—, and the repeating numbers k to 1 are each independently 0 The number of repetitions m and n is a molar ratio satisfying the relational expression of 0.05 <n / (n + m) <0.6.

(In the general formula (8), a plurality of substituents Re 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. o is an integer of 0-4.)

(In the general formula (9), the plurality of substituents Rf 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. p is an integer of 0-4.)   2. The electron according to claim 1, wherein the weight average molecular weight of the first binder resin is 40,000 or more and the weight average molecular weight of the second binder resin is a value less than 40,000. Photoconductor.   Of the first binder resin and the second binder resin, the content of the second binder resin having a small weight average molecular weight is set to a value of 50% by weight or more based on the total amount of the binder resin. The electrophotographic photosensitive member according to claim 1 or 2. The value (I / O value) obtained by dividing the inorganic degree in the polycarbonate resin represented by the general formula (7) by the organic degree is set to a value of 0.37 or more. The electrophotographic photoreceptor according to any one of the above. It said photosensitive layer, as an additive, an electrophotographic photosensitive member according to any one of claims 1 to 4, characterized by containing a compound represented by the following general formula (10).

(In General Formula (10), R ^{10 to} R ¹⁹ 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 aralkyl group having 6 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms, a hydroxyl group, A cyano group, a nitro group, or an amino group, R is a substituted or unsubstituted alkylene group having 1 to 12 carbon atoms, or an organic group containing a nitrogen atom, and n represents an integer of 0 to 3). 6. The electrophotographic photosensitive member according to claim 5 , wherein the additive is added in a value within a range of 1 to 15% by weight with respect to the total amount of solid content of the photosensitive layer. Together comprising an electrophotographic photosensitive member according to any one of claims 1 to 6 around the electrophotographic photosensitive member, a charging means, an exposure means, a developing means, a transfer means is arranged, and wherein the developing means As an image forming apparatus, a simultaneous development cleaning system is used.