JP2018010240A - Electrophotographic photoreceptor, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor that reduces the generation of black spots.SOLUTION: An electrophotographic photoreceptor comprises: a conductive substrate; an undercoat layer that is provided on the conductive substrate, the undercoat layer being a cured product of a composition containing a charge transport material including at least one substituent selected from the group consisting of -OH, -OCH, -NH, -SH, and -COOH; and a single-layer photosensitive layer that is provided on the undercoat layer, the photosensitive layer containing a binder resin, a charge generating material, a hole transport material, and an electron transport material.SELECTED DRAWING: None

Description

  The present invention relates to an electrophotographic photosensitive member, a process cartridge, and an image forming apparatus.

  Patent Document 1 discloses a positively charged single-layer organic electrophotographic photoreceptor in which a photosensitive layer containing a charge generation material and a charge transport material is formed on an electrically conductive substrate via an intermediate layer. An electrophotographic photosensitive member is disclosed in which the material of the intermediate layer is a polyvinyl acetal resin composed of a structural unit represented by a specific chemical structural formula.

  Patent Document 2 discloses an electrophotographic photosensitive member having a support substrate, an intermediate layer, and a photosensitive layer, the intermediate layer including a phenol-based resin, a film-forming resin having a hydroxyl group, a hole transport agent, When the addition amount of the phenolic resin is A1 and the addition amount of the film-forming resin having a hydroxyl group is A2, the phenolic resin content (A1 / (A1 + A2) × 100) is 10% by mass. An electrophotographic photosensitive member having a value in the range of 80% by mass or less is disclosed.

  Patent Document 3 discloses an electrophotographic photosensitive member having a support substrate, an intermediate layer, and a photosensitive layer, the intermediate layer containing an alcohol-soluble polyamide resin and a hole transport material, and an alcohol. An electrophotographic photosensitive member is disclosed in which the amount of the hole transport material added is in the range of 1 to 100 parts by mass with respect to 100 parts by mass of the soluble polyamide resin.

  In Patent Document 4, an electrophotographic photosensitive member in which a single-layer type photosensitive layer containing a charge generation material, a hole transport material, an electron transport material, and a binder resin is formed on a conductive substrate via an undercoat layer. A positively charged single layer type electrophotographic image wherein the undercoat layer is composed of at least titanium oxide and a binder resin, titanium oxide is surface-treated with alumina and silica, and the number average primary particle size is 20 nm or less. A photoreceptor is disclosed.

Japanese Patent Laid-Open No. 11-344825 JP 2005-215119 A JP 2006-047344 A JP 2007-248560 A

As an electrophotographic photosensitive member having a single-layer type photosensitive layer on a conductive substrate, a single-layer type photosensitive layer is directly provided on the conductive substrate without a subbing layer from the viewpoint of cost reduction. There are many. When a photoconductor in which a single-layer type photosensitive layer is directly provided on a conductive substrate is used, there are cases where black spots are likely to occur.
In addition, a photoconductor in which a single-layer type photosensitive layer is provided on a conductive substrate via an undercoat layer does not have an undercoat layer, but a photoconductor in which a single-layer type photoconductive layer is directly provided. In comparison, it is easy to suppress a leakage current from the conductive substrate, which is advantageous in terms of image quality. However, the conventional undercoat layer is often formed by dispersing metal oxide fine particles in, for example, an alcohol-soluble resin (for example, nylon resin or butyral resin) or an alcohol-soluble resin, and forms a photosensitive layer. When the undercoat layer dissolves or swells with the solvent in the photosensitive layer forming coating solution, or the undercoat layer absorbs moisture, the function of the undercoat layer deteriorates in a high-temperature and high-humidity environment, and black spots are generated. was there.

  Accordingly, the problem of the present invention is that an electrophotographic photosensitive member having a single-layer type photosensitive layer on a conductive substrate has a single-layer type photosensitive layer provided directly on the conductive substrate, or a conductive layer. In the case of having an undercoat layer formed from a composition containing a nylon resin and zinc oxide particles between the substrate and the single-layer type photosensitive layer, or a silane coupling agent-treated zinc oxide and a blocked isocyanate compound It is an object of the present invention to provide an electrophotographic photosensitive member in which the generation of black spots in a high-temperature and high-humidity environment is suppressed as compared with the case of having an undercoat layer formed from a composition containing the same.

  The above problem is solved by the following means.

The invention according to claim 1
A conductive substrate;
A charge transporting material having at least one substituent selected from the group consisting of —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH, which is an undercoat layer provided on the conductive substrate An undercoat layer that is a cured product of a composition containing
A single-layer type photosensitive layer provided on the undercoat layer, the photosensitive layer comprising a binder resin, a charge generation material, a hole transport material, and an electron transport material;
An electrophotographic photosensitive member having

The invention according to claim 2
The electrophotographic photosensitive member according to claim 1, wherein the charge transporting material is a compound represented by the following general formula (I).
(I) F - ((- R 1 -O) n1 R 2 -Y) n2
(In general formula (I), F is an organic group derived from a compound having a hole transporting ability, R ¹ and R ² are each independently a linear or branched alkylene group having 1 to 5 carbon atoms. N1 represents 0 or 1, n2 represents an integer of 1 to 4, O represents oxygen, and Y independently represents —OH, —OCH ₃ , —NH ₂ , —SH, or — COOH is shown.)

The invention according to claim 3
The electrophotographic photoreceptor according to claim 1, wherein the composition further contains at least one curable compound selected from a phenol compound, a melamine compound, a guanamine compound, and an isocyanate compound.

The invention according to claim 4
The electrophotographic photosensitive member according to claim 1, wherein the composition further contains metal oxide particles.

The invention according to claim 5
5. The electrophotographic photoreceptor according to claim 1, wherein the charge generation material is at least one selected from hydroxygallium phthalocyanine pigments and chlorogallium phthalocyanine pigments.

The invention according to claim 6
The electrophotographic photoreceptor according to any one of claims 1 to 5,
It is a process cartridge that is detachably attached to the image forming apparatus.

The invention according to claim 7 provides:
The electrophotographic photosensitive member according to any one of claims 1 to 5,
Charging means for charging the surface of the electrophotographic photosensitive member;
An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image;
Transfer means for transferring the toner image to the surface of the recording medium;
An image forming apparatus.

  According to the invention of claim 1, 2, 3, 4, or 5, in the electrophotographic photosensitive member having a single layer type photosensitive layer on the conductive substrate, the single layer type directly provided on the conductive substrate. A photosensitive layer, or a subbing layer formed of a composition containing nylon resin and zinc oxide particles between a conductive substrate and a single-layer type photosensitive layer, or silane coupling An electrophotographic photosensitive member is provided in which the generation of black spots is suppressed as compared to the case of having an undercoat layer formed from a composition containing an agent-treated zinc oxide and a blocked isocyanate compound.

  According to the invention according to claim 6 or 7, in the electrophotographic photosensitive member having a single-layer type photosensitive layer on the conductive substrate, when the single-layer type photosensitive layer is provided directly on the conductive substrate, Or when it has an undercoat layer formed from a composition containing nylon resin and zinc oxide particles between the conductive substrate and the single-layer type photosensitive layer, or blocked with silane coupling agent-treated zinc oxide Provided is a process cartridge or an image forming apparatus provided with an electrophotographic photosensitive member in which the generation of black spots is suppressed as compared with the case of having an undercoat layer formed from a composition containing an isocyanate compound.

1 is a schematic partial cross-sectional view showing an electrophotographic photosensitive member according to the present embodiment. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows the other example of the image forming apparatus which concerns on this embodiment.

  Embodiments that are examples of the present invention will be described below.

<Electrophotographic photoreceptor>
The electrophotographic photoreceptor according to the exemplary embodiment (hereinafter sometimes referred to as “photoreceptor”) includes a conductive substrate, and a positive layer having an undercoat layer and a single-layer type photosensitive layer on the conductive substrate. It is a charged organic photoreceptor (hereinafter sometimes referred to as “single-layer photoreceptor”).
The undercoat layer is formed of a charge transporting material having at least one substituent selected from the group consisting of —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH (hereinafter referred to as “specific charge transporting material”). ”). The single-layer type photosensitive layer includes a binder resin, a charge generation material, a hole transport material, and an electron transport material.
The single-layer type photosensitive layer is a photosensitive layer having hole transporting properties and electron transporting properties as well as charge generation ability.

The single-layer type photoreceptor has the advantage that the number of coating steps is small and the manufacturing cost is low as compared with the photoreceptor having a laminated type photosensitive layer. In recent years, for example, a photoreceptor applied to an inexpensive image forming apparatus. It is attracting attention as.
In consideration of cost reduction, this single-layer type photoreceptor does not have an undercoat layer, and a photosensitive layer is often provided directly on a conductive substrate. On the other hand, a single-layer type photoreceptor having a single-layer type photosensitive layer directly on a conductive substrate is a charge leak from the conductive substrate to the photosensitive layer, or from the photosensitive layer to the conductive substrate. Image quality defects such as black spots may occur due to the influence of charge injection or the like.

  Here, the single-layer type photoreceptor is advantageous in that an undercoat layer is interposed between the conductive substrate and the single-layer type photosensitive layer in terms of improving the image quality. However, conventionally, the undercoat layer may be formed of, for example, a component that is dissolved by a polar organic solvent. In this case, the undercoat layer may be dissolved or swollen by the polar organic solvent contained in the photosensitive layer forming coating solution. In particular, under high temperature and high humidity, the function as the undercoat layer is affected by moisture and black spots may be generated.

On the other hand, as the undercoat layer interposed between the conductive substrate and the single-layer type photosensitive layer, for example, an alcohol-soluble resin (for example, nylon resin, butyral which is difficult to dissolve in the organic solvent of the photosensitive layer forming coating solution). A subbing layer using a resin is known. Since this undercoat layer is formed to contain an alcohol-soluble resin, dissolution, swelling, and the like of the undercoat layer by an organic solvent in the photosensitive layer forming coating solution are likely to be suppressed.
However, for example, an undercoat layer containing an alcohol-soluble resin has high hygroscopicity, so it is easily affected by environmental changes, and the amount of variation in electrical characteristics tends to increase between a high temperature and high humidity environment and a low temperature and low humidity environment. . It is also known that the electrical resistance is adjusted by including metal oxide particles, but depending on the drying conditions, the dispersibility of the metal oxide particles may be reduced due to alteration of the resin, etc., or the undercoat layer may be uneven. For example, the undercoat layer may have uneven resistance, and black spots may be easily generated.

  In contrast, the electrophotographic photosensitive member according to the present embodiment suppresses the generation of black spots by the above configuration. The reason is not clear, but is presumed as shown below.

  In the electrophotographic photoreceptor according to the exemplary embodiment, the undercoat layer is formed of a cured product (crosslinked product or polymer) of a composition containing a specific charge transporting material. For this reason, it is suppressed that an undercoat layer is melt | dissolved or swollen with the organic solvent of the coating liquid for photosensitive layer formation. Further, the cured product of the composition containing the specific charge transporting material has lower hygroscopicity and higher thermal stability than the undercoat layer containing an alcohol-soluble resin.

  By the way, since the single layer type photoreceptor is a positively charged type photoreceptor, when the undercoat layer is provided, the undercoat layer ideally has a hole transport ability and suppresses the transport of electrons. It is preferable to have characteristics. Since the specific charge transporting material has the ability to suppress the transport of electrons while having the hole transporting ability, the undercoat layer formed by the cured product of the composition containing the specific charge transporting material is a single layer. It is considered that it is suitable as an undercoat layer for a type photoreceptor.

Therefore, the undercoat layer of the electrophotographic photosensitive member according to the present embodiment suppresses phenomena such as dissolution and swelling caused by the solvent of the photosensitive layer forming coating solution, and also suppresses hygroscopicity. It is considered that the deterioration of the function as a layer is suppressed. In addition, the undercoat layer of the electrophotographic photosensitive member according to this embodiment has a property of suppressing electron transport while having a hole transporting capability. Therefore, the undercoat layer provided on the positively charged photosensitive member is provided. It is considered to have suitable performance as a layer.
For the above reasons, it is presumed that the electrophotographic photosensitive member according to the exemplary embodiment suppresses the generation of black spots by the above configuration.

For example, in the case of a subbing layer containing a conventional alcohol-soluble nylon resin, the conductive substrate may corrode due to moisture absorption of the resin, and the life of the single-layer type photoreceptor is likely to be shortened.
On the other hand, the electrophotographic photoreceptor according to the present embodiment has almost no hygroscopicity because it is formed of a cured product of a composition containing a specific charge transporting material. For this reason, there is an advantage that the life of the photosensitive member can be extended.

Hereinafter, the electrophotographic photoreceptor according to the exemplary embodiment will be described in detail with reference to the drawings.
FIG. 1 schematically shows a partial cross section of an electrophotographic photosensitive member 7 according to this embodiment.
The electrophotographic photoreceptor 7 shown in FIG. 1 includes, for example, a conductive substrate 3, and an undercoat layer 1 and a single-layer type photosensitive layer 2 are provided on the conductive substrate 3 in this order. Yes.
Moreover, you may provide another layer as needed. Specifically, for example, a protective layer may be provided on the single-layer type photosensitive layer 2 as necessary.

  Hereinafter, each layer of the electrophotographic photoreceptor according to the exemplary embodiment will be described in detail. Note that the reference numerals are omitted.

(Conductive substrate)
Examples of the conductive substrate include metal plates (eg, aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or alloys (stainless steel, etc.), metal drums, metal belts, etc. Is mentioned. In addition, as the conductive substrate, for example, paper, resin film, belt, etc. coated, vapor-deposited or laminated with a conductive compound (for example, conductive polymer, indium oxide, etc.), metal (for example, aluminum, palladium, gold, etc.) or an alloy, etc. Also mentioned. Here, “conductive” means that the volume resistivity is less than 10 ¹³ Ωcm.

The thickness of the conductive substrate is preferably from 0.3 mm to 3 mm, and more preferably from 0.4 mm to 1 mm in terms of mechanical strength and manufacturability.
When the electrophotographic photosensitive member is used in a laser printer, the surface of the conductive substrate has a center line average roughness Ra of 0.04 μm or more and 0.5 μm for the purpose of suppressing interference fringes generated when laser light is irradiated. The surface is preferably roughened below. When non-interfering light is used as a light source, roughening for preventing interference fringes is not particularly required, but it is suitable for extending the life because it suppresses generation of defects due to irregularities on the surface of the conductive substrate.

  Examples of roughening methods include wet honing by suspending an abrasive in water and spraying the conductive substrate, centerless grinding in which the conductive substrate is pressed against a rotating grindstone, and grinding is performed continuously. And anodizing treatment.

  As a roughening method, without roughening the surface of the conductive substrate, conductive or semiconductive powder is dispersed in the resin to form a layer on the surface of the conductive substrate. The method of roughening by the particle | grains disperse | distributed in a layer is also mentioned.

  In the roughening treatment by anodic oxidation, a metal (for example, aluminum) conductive substrate is used as an anode, and an oxide film is formed on the surface of the conductive substrate by anodizing in an electrolyte solution. Examples of the electrolyte solution include a sulfuric acid solution and an oxalic acid solution. However, the porous anodic oxide film formed by anodic oxidation is chemically active as it is, easily contaminated, and has a large resistance fluctuation due to the environment. Therefore, the pores of the oxide film are blocked by the volume expansion due to the hydration reaction in pressurized water vapor or boiling water (a metal salt such as nickel may be added) against the porous anodic oxide film, and more stable hydration oxidation It is preferable to perform a sealing treatment for changing to a product.

  The thickness of the anodized film is preferably, for example, 0.3 μm or more and 15 μm or less. When this film thickness is within the above range, the barrier property against implantation tends to be exhibited, and the increase in residual potential due to repeated use tends to be suppressed.

The conductive substrate may be treated with an acidic treatment liquid or boehmite treatment.
The treatment with the acidic treatment liquid is performed as follows, for example. First, an acidic treatment liquid containing phosphoric acid, chromic acid and hydrofluoric acid is prepared. The mixing ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment liquid is, for example, in the range of 10% by mass to 11% by mass of phosphoric acid, in the range of 3% by mass to 5% by mass of chromic acid, The concentration of these acids is preferably in the range of 13.5% by mass or more and 18% by mass or less. The treatment temperature is preferably 42 ° C. or higher and 48 ° C. or lower, for example. The film thickness is preferably from 0.3 μm to 15 μm.

  The boehmite treatment is performed, for example, by immersing in pure water of 90 ° C. or higher and 100 ° C. or lower for 5 minutes to 60 minutes, or by contacting with heated steam of 90 ° C. or higher and 120 ° C. or lower for 5 minutes to 60 minutes. The film thickness is preferably 0.1 μm or more and 5 μm or less. This may be further anodized using an electrolyte solution with low film solubility such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, citrate, etc. Good.

(Undercoat layer)
The undercoat layer contains a charge transporting material (specific charge transporting material) having at least one substituent selected from the group consisting of —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. It is a cured product. In addition, the composition for forming the undercoat layer may contain components such as a curable compound and metal oxide particles as necessary.

Next, the specific charge transport material will be described. The specific charge transporting material is a compound having a charge transporting property having at least one substituent selected from the group consisting of —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. In particular, the specific charge transporting material has at least two (or three) substituents (reactive functional groups) selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. A thing is mentioned suitably. The specific charge transporting material increases the number of substituents, thereby increasing the curing (crosslinking) density. Therefore, when the photosensitive layer forming coating solution is applied onto the undercoat layer, dissolution, swelling, and the like of the undercoat layer caused by the organic solvent in the photosensitive layer forming coating solution are more easily suppressed.

The specific charge transporting material is preferably a compound represented by the following general formula (I).
(I) F - ((- R 1 -O) n1 R 2 -Y) n2

In general formula (I), F represents an organic group derived from a compound having a hole transporting ability, and R ¹ and R ² each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms. , N1 represents 0 or 1, and n2 represents an integer of 1 or more and 4 or less. O represents oxygen and Y independently represents —OH, —OCH ₃ , —NH ₂ , —SH, or —COOH.

  In general formula (I), an arylamine derivative is preferably used as the compound having a hole transporting ability in an organic group derived from a compound having a hole transporting ability represented by F. Preferred examples of the arylamine derivative include a triphenylamine derivative and a tetraphenylbenzidine derivative.

  And it is preferable that the compound shown by general formula (I) is a compound shown by the following general formula (II). The compound represented by the general formula (II) is particularly excellent in charge mobility, stability against oxidation and the like.

In general formula (II), Ar ^{1 to} Ar ⁴ may be the same or different and each independently represents a substituted or unsubstituted aryl group, and Ar ⁵ represents a substituted or unsubstituted aryl group or substituted or unsubstituted. D represents — (— R ¹ —O) _n1 R ² —Y, c represents 0 or 1 independently, k represents 0 or 1, and the total number of D is 1 or more and 4 It is as follows. R ¹ and R ² each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms, n1 represents 0 or 1, O represents oxygen, Y represents —OH, — OCH _{3, -NH} 2, shown -SH, or -COOH.

In the general formula (II), “— (— R ¹ —O) _n1 R ² —Y” representing D is the same as in the general formula (I), and R ¹ and R ² each independently have 1 or more carbon atoms. 5 or less linear or branched alkylene group. N1 is preferably 1. Y is preferably a hydroxyl group.
In addition, the total number of D in General formula (II) is equivalent to n2 in General formula (I), Preferably it is 2-4, More preferably, it is 3-4. That is, in the general formula (I) and the general formula (II), the total number of D is preferably 2 or more and 4 or less, more preferably 3 or more and 4 or less in one molecule. When the photosensitive layer forming coating solution is applied on the undercoat layer, dissolution, swelling, and the like of the undercoat layer caused by the organic solvent in the photosensitive layer forming coating solution are more easily suppressed.

In general formula (II), Ar ^{1 to} Ar ⁴ are preferably any of the following formulas (1) to (7). Incidentally, the following equation (1) to (7) can be coupled to each Ar ¹ to Ar ⁴ - shown with _{"(D) C".}

In formulas (1) to (7), R ⁹ is a phenyl substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. 1 type chosen from the group which consists of group, an unsubstituted phenyl group, and a C7-C10 aralkyl group. R ^{10 to} R ¹² are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group substituted with an alkoxy group having 1 to 4 carbon atoms, 1 type chosen from the group which consists of a substituted phenyl group, a C7-C10 aralkyl group, and a halogen atom. Ar represents a substituted or unsubstituted arylene group. D and c are the same as “D” and “c” in the general formula (II), s represents 0 or 1, and t represents an integer of 1 or more and 3 or less.

Here, as Ar in Formula (7), what is represented by following formula (8) or (9) is preferable.

In formulas (8) and (9), R ¹³ and R ¹⁴ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. 1 type selected from the group consisting of a phenyl group substituted with, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom. t represents an integer of 1 or more and 3 or less.

  Further, as Z ′ in the formula (7), those represented by any of the following formulas (10) to (17) are preferable.

In formulas (10) to (17), R ¹⁵ and R ¹⁶ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. 1 type selected from the group consisting of a substituted phenyl group, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom. W represents a divalent group, and q and r each represent an integer of 1 or more and 10 or less. t represents an integer of 1 to 3, respectively.

  W in the formulas (16) to (17) is preferably any one of divalent groups represented by the following (18) to (26). However, in formula (25), u represents an integer of 0 or more and 3 or less.

In general formula (II), Ar ⁵ is the aryl group of the above (1) to (7) exemplified in the description of Ar ^{1 to} Ar ⁴ when k is 0, and when k is 1, An arylene group obtained by removing a hydrogen atom from the aryl groups of the above (1) to (7).

  Specific examples of the compound represented by the general formula (I) include the exemplified compounds (I-1) to (I-34) shown below. In addition, the compound shown by the said general formula (I) is not limited at all by these.

  The content of the specific charge transporting material in all the components (material remaining as a solid content) used for forming the undercoat layer is not particularly limited, but is preferably 10% by mass or more. The upper limit is preferably 98% by mass or less. More preferably, it is 30 mass% or more and 95 mass% or less. The specific charge transport material may be used alone or in combination of two or more. The content when two or more specific charge transport materials are used in combination is the total amount of the specific charge transport materials.

-Curable compound-
The curable compound is not particularly limited as long as it is a compound capable of reacting with a specific charge transporting material. For example, a phenol compound (a compound having a phenol skeleton), a melamine compound (a compound having a melamine skeleton), a guanamine compound. It is preferable to use at least one compound selected from the group consisting of (a compound having a guanamine skeleton) and an isocyanate compound (a compound having an isocyanate skeleton).
The specific charge transporting material and the curable compound preferably have a mass ratio of 99: 1 to 1:99, more preferably 99: 1 to 50:50.

  As phenol compounds, substituted phenols containing one hydroxyl group such as phenol, cresol, xylenol, paraalkylphenol, paraphenylphenol; substituted phenols containing two hydroxyl groups such as catechol, resorcinol, hydroquinone; bisphenol A, bisphenol Z, etc. And compounds having a phenol structure such as bisphenols; biphenols; and aldehydes such as formaldehyde and paraformaldehyde are reacted in the presence of an acid or alkali catalyst. And the monomer of monomethylol phenol obtained by reaction, dimethylol phenol, the monomer of trimethylol phenol, multimer (The repeating of the structural unit of a molecule is 2-20), two or more types of monomers A mixture, a mixture of two or more multimers, a mixture of one or two or more monomers and one or two or more multimers, and the like are used.

  As a melamine compound and a guanamine compound, a known method using melamine and formaldehyde (for example, see Experimental Chemistry Course 4th edition, Volume 28, page 430) and a known method using guanamine and formaldehyde (for example, Examples include compounds synthesized in Experimental Chemistry Course 4th edition, volume 28, page 430). The melamine compound and guanamine compound are a methylol type in which the methylol group is intact, a full ether type in which all the methylol groups are alkyl etherified, a fluino type in which all of the methylol groups are iminated, and a mixed type of a methylol group and an imino group. Various things can be used. As the melamine compound and the guanamine compound, a full ether type is preferably used from the viewpoint of the stability of the composition.

  Examples of the isocyanate compound include polyfunctional isocyanates, isocyanurates, and blocked isocyanates obtained by blocking these with blocking agents (blocking agents) such as alcohols and ketones. As the isocyanate compound, blocked isocyanate or isocyanurate is preferably used from the viewpoint of the stability of the composition.

When the specific charge transporting material is used alone, it is preferably cured using an acid catalyst when used in combination with a phenol compound, a melamine compound or a guanamine compound. On the other hand, when a specific charge transporting material and an isocyanate compound are mixed and used, an amine catalyst or a metal catalyst is preferably used.
The amount of the catalyst is preferably in the range of 0.01% by mass or more and 20% by mass or less (preferably 0.1% by mass or more and 10% by mass or less) with respect to the solid content 100 of the undercoat layer. The temperature for the curing reaction is preferably in the range of room temperature (for example, 25 ° C.) to 200 ° C. (preferably 100 ° C. to 150 ° C.).

  Examples of the acid catalyst include aliphatic carboxylic acids such as acetic acid, chloroacetic acid, trichloroacetic acid, trifluoroacetic acid, oxalic acid, maleic acid, malonic acid, and lactic acid; benzoic acid, phthalic acid, terephthalic acid, trimellitic acid, and the like. Aromatic carboxylic acids; Aliphatic sulfonic acids such as methanesulfonic acid and dodecylsulfonic acid; and aromatic sulfonic acids such as benzenesulfonic acid, dodecylbenzenesulfonic acid and naphthalenesulfonic acid.

  Specific commercial products include “NACURE2501” (toluenesulfonic acid dissociation, methanol / isopropanol solvent, pH 6.0 to pH7.2, dissociation temperature 80 ° C.), “NACURE2107” (p-toluenesulfone) manufactured by King Industries. Acid dissociation, isopropanol solvent, pH 8.0 to pH 9.0, dissociation temperature 90 ° C.), “NACURE 2500” (p-toluenesulfonic acid dissociation, isopropanol solvent, pH 6.0 to pH 7.0, dissociation temperature 65 ° C.), “NACURE2530” (p-toluenesulfonic acid dissociation, methanol / isopropanol solvent, pH 5.7 to pH6.5, dissociation temperature 65 ° C.), “NACURE2547” (p-toluenesulfonic acid dissociation, aqueous solution, pH 8.0 to pH 9. 0 or less, dissociation temperature 107 ° C.), “NACURE2558” (p-toluenesulfonic acid dissociation, ethylene / glycol solvent, pH 3.5 to pH 4.5, dissociation temperature 80 ° C.), “NACUREXP-357” (p-toluenesulfonic acid dissociation, methanol solvent) , PH 2.0 to pH 4.0, dissociation temperature 65 ° C.), “NACUREXP-386” (p-toluenesulfonic acid dissociation, aqueous solution, pH 6.1 to pH 6.4, dissociation temperature 80 ° C.), “NACUREX C-2211 (P-toluenesulfonic acid dissociation, pH 7.2 to pH 8.5, dissociation temperature 80 ° C.), “NACURE 5225” (dodecylbenzenesulfonic acid dissociation, isopropanol solvent, pH 6.0 to pH 7.0, dissociation temperature 120 ° C. ), “NACURE 5414” (dodecylbenzenesulfone) Dissociation, xylene solvent, dissociation temperature 120 ° C), "NACURE 5528" (dodecylbenzenesulfonic acid dissociation, isopropanol solvent, pH 7.0 to pH 8.0, dissociation temperature 120 ° C), "NACURE5925" (dodecylbenzenesulfonic acid dissociation, pH 7 0.0 to pH 7.5, dissociation temperature 130 ° C., “NACURE 1323” (dinonylnaphthalenesulfonic acid dissociation, xylene solvent, pH 6.8 to pH 7.5, dissociation temperature 150 ° C.), “NACURE 1419” (dinonyl naphthalene) Sulfonic acid dissociation, xylene / methyl isobutyl ketone solvent, dissociation temperature 150 ° C., “NACURE1557” (dinonylnaphthalene sulfonic acid dissociation, butanol / 2-butoxyethanol solvent, pH 6.5 to pH 7.5, dissociation temperature 150 ° C. ), “NACUREX49-110” (dinonyl naphthalene disulfonic acid dissociation, isobutanol / isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 90 ° C.), “NACURE 3525” (dinonyl naphthalene disulfonic acid dissociation, isobutanol / Isopropanol solvent, pH 7.0 to pH 8.5, dissociation temperature 120 ° C., “NACUREXP-383” (dinonylnaphthalenedisulfonic acid dissociation, xylene solvent, dissociation temperature 120 ° C.), “NACURE3327” (dinonylnaphthalenedisulfonic acid dissociation) , Isobutanol / isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 150 ° C., “NACURE4167” (phosphate dissociation, isopropanol / isobutanol solvent, pH 6.8 to pH 7.3, solution 80 ° C.), “NACUREXP-297” (phosphoric acid dissociation, water / isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 90 ° C., “NACURE 4575” (phosphoric acid dissociation, pH 7.0 to pH 8.0) , Dissociation temperature 110 ° C.) and the like.

Examples of the amine catalyst include 1,4-diazabicyclo (2,2,2) octane, N, N-dimethylcyclohexylamine, N-methyldicyclohexylamine, N, N, N ′, N′-tetramethylpropylenediamine. N-ethylmorpholine, N-methylmorpholine, N, N-dimethylethanolamine, 1,8-diazabicyclo [5,4,0] undecene-7 (DBU) and salts thereof.
Examples of the metal catalyst include dibutyltin laurate and stannous octoate.

-Metal oxide particles-
Examples of the metal oxide particles include metal oxide particles having a powder resistance (volume resistivity) of 10 ² Ωcm or more and 10 ¹¹ Ωcm or less.
Among these, as the metal oxide particles having the above resistance value, for example, metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles are preferable, and zinc oxide particles are particularly preferable.

The specific surface area of the metal oxide particles according to the BET method is preferably 10 m ² / g or more, for example.
The volume average particle diameter of the metal oxide particles is, for example, 50 nm or more and 2000 nm or less (preferably 60 nm or more and 1000 nm or less).

  The content of the metal oxide particles is, for example, preferably 10% by mass or more and 80% by mass or less, and more preferably 40% by mass or more and 80% by mass or less with respect to the binder resin.

  The metal oxide particles may be subjected to a surface treatment. Two or more kinds of metal oxide particles having different surface treatments or particles having different particle diameters may be mixed and used.

  Examples of the surface treatment agent include a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, and a surfactant. In particular, a silane coupling agent is preferable, and an amino group-containing silane coupling agent is more preferable.

  Examples of the silane coupling agent having an amino group include 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and N-2- (aminoethyl) -3-amino. Examples include, but are not limited to, propylmethyldimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, and the like.

  Two or more silane coupling agents may be used in combination. For example, a silane coupling agent having an amino group and another silane coupling agent may be used in combination. Other silane coupling agents include, for example, vinyltrimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycol. Sidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- ( Aminoethyl) -3-aminopropylmethyldimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, and the like, but are not limited thereto. It is not a thing.

  The surface treatment method using the surface treatment agent may be any method as long as it is a known method, and may be either a dry method or a wet method.

  The treatment amount of the surface treatment agent is preferably 0.5% by mass or more and 10% by mass or less with respect to the metal oxide particles, for example.

-Additives-
The undercoat layer may contain various additives for improving electrical characteristics, improving environmental stability, and improving image quality.
Additives include known materials such as electron transport pigments such as polycyclic condensation systems and azo systems, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, and silane coupling agents. It is done. The silane coupling agent is used for the surface treatment of the metal oxide particles as described above, but may be further added to the undercoat layer as an additive.

  Examples of the silane coupling agent as the additive include vinyltrimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3- Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (Aminoethyl) -3-aminopropylmethylmethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane and the like can be mentioned.

  Examples of the zirconium chelate compound include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Examples of titanium chelate compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt. , Titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, polyhydroxy titanium stearate and the like.

  Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.

  These additives may be used alone or as a mixture or polycondensate of a plurality of compounds.

The undercoat layer preferably has a Vickers hardness of 35 or more.
The surface roughness (ten-point average roughness) of the undercoat layer is from 1 / (4n) (where n is the refractive index of the upper layer) to 1/2 of the exposure laser wavelength λ used to suppress moire images. It is good that it is adjusted to.

  Resin particles or the like may be added to the undercoat layer for adjusting the surface roughness. Examples of the resin particles include silicone resin particles and cross-linked polymethyl methacrylate resin particles. Further, the surface of the undercoat layer may be polished for adjusting the surface roughness. Examples of the polishing method include buffing, sandblasting, wet honing, and grinding.

  The formation of the undercoat layer is not particularly limited, and a well-known formation method is used. For example, a coating solution for forming an undercoat layer (a composition for forming an undercoat layer) in which the above components are added to a solvent is used. A film is formed, and the coating film is dried and cured.

Solvents for preparing the coating solution for forming the undercoat layer include known organic solvents such as alcohol solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone solvents, ketone alcohol solvents, ether solvents. Examples include solvents and ester solvents.
Specific examples of these solvents include methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, Examples include ordinary organic solvents such as n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene.

  Examples of the method for dispersing the metal oxide particles when preparing the coating solution for forming the undercoat layer include known methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker.

  Examples of the method for applying the coating liquid for forming the undercoat layer onto the conductive substrate include, for example, a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method. The usual methods, such as these, are mentioned.

  The curing temperature of the coating film is not particularly limited as long as the crosslinking reaction occurs, but a temperature equal to or higher than the boiling point of the solvent to be used is preferable. Specifically, for example, a range of 80 ° C. to 200 ° C. is preferable, and a range of 100 ° C. to 170 ° C. is more preferable.

  The thickness of the undercoat layer is preferably set within a range of, for example, 0.05 μm to 5 μm (preferably 0.1 μm to 1 μm). When the thickness of the undercoat layer is within the above range, the generation of black spots is easily suppressed and the increase in residual potential is also easily suppressed.

(Single layer type photosensitive layer)
The single-layer type photosensitive layer includes a binder resin, a charge generation material, a hole transport material, and an electron transport material, and may include other additives as necessary.

  The binder resin is not particularly limited. For example, polycarbonate resin, polyester resin, polyarylate resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene. Copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin , Poly-N-vinylcarbazole, polysilane and the like. These binder resins may be used alone or in combination of two or more.

Among these binder resins, polycarbonate resins and polyarylate resins are preferable from the viewpoint of mechanical strength of the photosensitive layer.
Further, from the viewpoint of film formability of the photosensitive layer, as the binder resin, for example, at least one of a polycarbonate resin having a viscosity average molecular weight of 30,000 to 80,000 and a polyarylate resin having a viscosity average molecular weight of 30,000 to 80,000 is used. Good.

The viscosity average molecular weight is measured by the following method. Specifically, 1 g of resin is dissolved in 100 cm ³ of methylene chloride, and its specific viscosity ηsp is measured with an Ubbelohde viscometer in a measurement environment at 25 ° C. Then, the intrinsic viscosity [η] (cm ³ / g) is obtained from the relational expression ηsp / c = [η] +0.45 [η] ² c (where c is the concentration (g / cm ³ )). Further, H.C. The viscosity average molecular weight Mv is determined from the equation given by Schnell, [η] = 1.23 × 10 ⁻⁴ Mv ^0.83 . Thus, for example, a one-point measuring method is used for measuring the viscosity average molecular weight.

  The content of the binder resin with respect to the total solid content of the photosensitive layer is, for example, 35% by mass to 60% by mass, and desirably 40% by mass to 55% by mass.

-Charge generation material-
The charge generation material is not particularly limited. For example, azo pigments such as bisazo and trisazo; fused aromatic pigments such as dibromoanthanthrone; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide; Etc.

  Among these, a metal phthalocyanine pigment or a metal-free phthalocyanine pigment is preferably used as the charge generation material in order to cope with near-infrared laser exposure. Specifically, for example, hydroxygallium phthalocyanine disclosed in JP-A-5-263007, JP-A-5-279591, etc .; chlorogallium phthalocyanine disclosed in JP-A-5-98181; Examples thereof include dichlorotin phthalocyanine disclosed in JP-A No. 140472, JP-A-5-140473, and titanyl phthalocyanine disclosed in JP-A-4-189873.

  On the other hand, in order to cope with near-ultraviolet laser exposure, as a charge generation material, a condensed aromatic pigment such as dibromoanthanthrone, a thioindigo pigment, a porphyrazine compound, zinc oxide, or trigonal selenium is used. Is good.

  That is, as the charge generation material, for example, when using a light source with an exposure wavelength of 380 nm to 500 nm, an inorganic pigment is preferably used. When using a light source with an exposure wavelength of 700 nm to 800 nm, metal and A metal phthalocyanine pigment is preferably used.

  Among these, as the charge generation material, it is desirable to use at least one selected from hydroxygallium phthalocyanine pigments and chlorogallium phthalocyanine pigments. These charge generation materials may be used alone or in combination of two or more. From the viewpoint of increasing the sensitivity of the photoreceptor, a hydroxygallium phthalocyanine pigment is preferable.

The hydroxygallium phthalocyanine pigment is not particularly limited, but a V-type hydroxygallium phthalocyanine pigment is preferable.
In particular, as a hydroxygallium phthalocyanine pigment, for example, in a spectral absorption spectrum in a wavelength region of 600 nm to 900 nm, a hydroxygallium phthalocyanine pigment having a maximum peak wavelength in a range of 810 nm to 839 nm can provide more excellent dispersibility. Desirable from a viewpoint. When used as a material for an electrophotographic photosensitive member, excellent dispersibility, sufficient sensitivity, chargeability, and dark decay characteristics are easily obtained.

The hydroxygallium phthalocyanine pigment having the maximum peak wavelength in the range of 810 nm to 839 nm is preferably in a specific range for the average particle size and in a specific range for the BET specific surface area. Specifically, the average particle size is desirably 0.20 μm or less, and more desirably 0.01 μm or more and 0.15 μm or less. On the other hand, the BET specific surface area is preferably 45 m ² / g or more, more preferably 50 m ² / g or more, and further preferably 55 m ² / g or more and 120 m ² / g or less. The average particle size is a volume average particle size (d50 average particle size) measured by a laser diffraction / scattering particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.). The BET specific surface area is a value measured by a nitrogen substitution method using a BET specific surface area measuring instrument (manufactured by Shimadzu Corporation: Flow Soap II2300).
Here, when the average particle diameter is larger than 0.20 μm, or when the specific surface area is less than 45 m ² / g, the pigment particles may be coarsened or aggregates of the pigment particles may be formed. In some cases, defects such as dispersibility, sensitivity, chargeability, and dark attenuation characteristics are likely to occur, which may cause image quality defects.

  The maximum particle size (maximum primary particle size) of the hydroxygallium phthalocyanine pigment is desirably 1.2 μm or less, more desirably 1.0 μm or less, and more desirably 0.3 μm or less. When the maximum particle size exceeds the above range, black spots tend to occur.

The hydroxygallium phthalocyanine pigment has an average particle size of 0.2 μm or less and a maximum particle size of 1.2 μm or less from the viewpoint of suppressing density unevenness due to exposure of the photoreceptor to a fluorescent lamp or the like, and The specific surface area value is desirably 45 m ² / g or more.

  The hydroxygallium phthalocyanine pigment has a Bragg angle (2θ ± 0.2 °) of at least 7.3 °, 16.0 °, 24.9 °, 28.0 ° in an X-ray diffraction spectrum using CuKα characteristic X-rays. It is desirable that it is a V type having a diffraction peak.

On the other hand, there is no particular limitation on the chlorogallium phthalocyanine pigment, but Bragg angles (2θ ± 0.2 °) of 7.4 °, 16.6 °, and 25. It is desirable to have diffraction peaks at 5 ° and 28.3 °.
The maximum peak wavelength, average particle diameter, maximum particle diameter, and specific surface area value of a suitable spectral absorption spectrum of the chlorogallium phthalocyanine pigment are the same as those of the hydroxygallium phthalocyanine pigment.

  The content of the charge generating material with respect to the total solid content of the photosensitive layer is preferably 1% by mass or more and 5% by mass or less, and preferably 1.2% by mass or more and 4.5% by mass or less.

-Hole transport material-
Although there is no restriction | limiting in particular as a hole transport material, For example, oxadiazole derivatives, such as 2, 5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole; Pyrazoline derivatives such as phenyl-pyrazoline, 1- [pyridyl- (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline; triphenylamine, N, N′-bis (3 Aromatic tertiary amino compounds such as 4-dimethylphenyl) biphenyl-4-amine, tri (p-methylphenyl) aminyl-4-amine, dibenzylaniline; N, N′-bis (3-methylphenyl)- Aromatic tertiary diamino compounds such as N, N'-diphenylbenzidine, 3- (4'-dimethylaminophenyl) -5,6-di- (4'-methoxyphene) 1) 1,2,4-triazine derivatives such as 1,2,4-triazine; hydrazone derivatives such as 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone; quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline Benzofuran derivatives such as 6-hydroxy-2,3-di (p-methoxyphenyl) benzofuran; α-stilbene derivatives such as p- (2,2-diphenylvinyl) -N, N-diphenylaniline; enamine derivatives; N -Carbazole derivatives such as ethyl carbazole; poly-N-vinyl carbazole and derivatives thereof; polymers having groups composed of the above-described compounds in the main chain or side chain; These hole transport materials may be used alone or in combination of two or more.

  Specific examples of the hole transport material include, for example, a compound represented by the following general formula (B-1), a compound represented by the following general formula (B-2), and the following general formula (B-3). Compounds. Furthermore, the compound represented by the following general formula (III) is mentioned.

In General Formula (B-1), R ^B1 represents a hydrogen atom or a methyl group. n11 represents 1 or 2. Ar ^B1 and Ar ^B2 are each independently a substituted or unsubstituted aryl group, —C ₆ H ₄ —C (R ^B3 ) ═C (R ^B4 ) (R ^B5 ), or —C ₆ H ₄ —CH═CH—. CH = C (R ^B6 ) (R ^B7 ), wherein R ^{B3 to} R ^B7 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. The substituent is a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a substituted amino group substituted with an alkyl group having 1 to 3 carbon atoms.

In general formula (B-2), R ^B8 and R ^{B8 ′} may be the same or different, and each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy having 1 to 5 carbon atoms. Group. R ^B9 , R ^{B9 ′} , R ^B10 , and R ^{B10 ′} may be the same or different and are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a carbon number. An amino group substituted with 1 or more and 2 or less alkyl groups, a substituted or unsubstituted aryl group, -C (R ^B11 ) = C (R ^B12 ) (R ^B13 ), or -CH = CH-CH = C (R ^B14 ) (R ^B15 ), and R ^{B11 to} R ^B15 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. m12, m13, n12 and n13 each independently represent an integer of 0 or more and 2 or less.

In general formula (B-3), R ^B16 and R ^{B16 ′} may be the same or different, and each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy having 1 to 5 carbon atoms. Group. R ^B17 , R ^{B17 ′} , R ^B18 , and R ^{B18 ′} may be the same or different and are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a carbon number. An amino group substituted with 1 or more and 2 or less alkyl groups, a substituted or unsubstituted aryl group, —C (R ^B19 ) ═C (R ^B20 ) (R ^B21 ), or —CH═CH—CH═C (R ^B22 ) (R ^B23 ), and R ^{B19 to} R ^B23 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. m14, m15, n14 and n15 each independently represent an integer of 0 or more and 2 or less.

Here, among the compound represented by the general formula (B-1), the compound represented by the general formula (B-2), and the compound represented by the general formula (B-3), in particular, “—C ₆ H ₄ -CH = CH-CH = C (R ^B6 ) (R ^B7 ) "and the compound represented by the general formula (B-1), and" -CH = CH-CH = C (R ^B14 ) (R ^B15 ) " A compound represented by the general formula (B-2) having the formula:

In the general formula (III), R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , and R ³⁶ are each independently a hydrogen atom, a lower alkyl group, an alkoxy group, a phenoxy group, a halogen atom, or a lower group. A phenyl group optionally having a substituent selected from an alkyl group, a lower alkoxy group and a halogen atom is shown. m and n each independently represents 0 or 1.

In the general formula (III), examples of the lower alkyl group represented by R ^{31 to} R ³⁶ include a linear or branched alkyl group having 1 to 4 carbon atoms. Examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and an isobutyl group.
Among these, the lower alkyl group is preferably a methyl group or an ethyl group.

In the general formula (III), examples of the alkoxy group represented by R ^{31 to} R ³⁶ include an alkoxy group having 1 to 4 carbon atoms, and specifically include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Etc.

In the general formula ^(III), the halogen atom represented by R 31 ^{to R 36,} for example, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In general formula (III), examples of the phenyl group represented by R ^{31 to} R ³⁶ include an unsubstituted phenyl group; a phenyl group substituted with a lower alkyl group such as a p-tolyl group or a 2,4-dimethylphenyl group; -A phenyl group substituted with a lower alkoxy group such as a methoxyphenyl group; a phenyl group substituted with a halogen atom such as a p-chlorophenyl group;
Examples of the substituent that can be substituted on the phenyl group include a lower alkyl group, a lower alkoxy group, and a halogen atom represented by R ^{31 to} R ³⁶ .

Among the hole transport materials of the general formula (III), from the viewpoint of increasing the sensitivity and suppressing the generation of the color point, a hole transport material in which m and n are 1 is good, and R ^{31 to} R ³⁶ are each independently, A hole transport material which represents a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms, or an alkoxy group, and m and n are 1 is desirable.

  Hereinafter, specific examples of the hole transport material include the following structural formulas (HT-1) to (HT-12), but the hole transport material is not limited thereto.

The content of the hole transport material with respect to the total solid content of the photosensitive layer is preferably 10% by mass or more and 40% by mass or less, and preferably 20% by mass or more and 35% by mass or less.
In addition, content of this hole transport material is content of those whole hole transport materials, when two or more types of hole transport materials are used together.

-Electron transport material-
Examples of the electron transport material include quinone compounds such as p-benzoquinone, chloranil, bromanyl, and anthraquinone; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone; dinaphthoquinone compounds; diphenoquinone Compounds: xanthone compounds; benzophenone compounds; cyanovinyl compounds; electron transport compounds such as ethylene compounds. These electron transport materials may be used alone or in combination of two or more, but are not limited thereto.

  Among these, as an electron transport material, it is desirable to use at least one selected from a fluorenone compound represented by the following formula (IV) and a diphenoquinone compound represented by the following formula (V).

In general formula (IV), R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , and R ⁴⁷ are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, or An aralkyl group is shown. R ⁴⁸ represents an alkyl group, —L ¹¹¹ —O—R ¹¹² , an aryl group, or an aralkyl group. ^{However, L 111} represents an alkylene ^{group, R 112} represents an alkyl group.

In the general formula (IV), examples of the halogen atom represented by R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , and R ⁴⁷ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Can be mentioned. Among these, a fluorine atom or a chlorine atom is preferable, and a chlorine atom is more preferable.

In general formula (IV), the alkyl group represented by R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , and R ⁴⁷ is, for example, linear or branched and has 1 or more carbon atoms. Examples include 20 or less alkyl groups. Examples of the linear alkyl group include a methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, and n-nonyl. Group, n-decyl group and the like.
Examples of the branched alkyl group include isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, neopentyl group, tert-pentyl group, isohexyl group, sec-hexyl group, tert-hexyl group, Isoheptyl group, sec-heptyl group, tert-heptyl group, isooctyl group, sec-octyl group, tert-octyl group, isononyl group, sec-nonyl group, tert-nonyl group, isodecyl group, sec-decyl group, tert-decyl Groups and the like. Among these, the carbon number of the alkyl group is more preferably 1 or more and 4 or less, and further preferably 1 or more and 3 or less.

In general formula (IV), examples of the alkoxy group represented by R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , and R ⁴⁷ include, for example, 1 to 4 carbon atoms (preferably 1 to 3 carbon atoms). ), Specifically, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and the like.

In general formula (IV), the aryl group represented by R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , and R ⁴⁷ may have a substituent, or have a substituent. There may be no such as, for example, a substituted or unsubstituted phenyl group. As a substituent which an aryl group has, a C1-C10 alkyl group, an alkoxy group, a halogen atom, etc. are mentioned, for example. Specific examples of the aryl group include a phenyl group, a methylphenyl group (tolyl group), a dimethylphenyl group, and an ethylphenyl group.

In General Formula (IV), examples of the aralkyl group represented by R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , and R ⁴⁷ include a group represented by —R ¹¹³ —Ar ¹¹⁴ . R ¹¹³ represents an alkylene group, and Ar ¹¹⁴ represents an aryl group.

The alkylene group R ¹¹³ represents, for example, linear or branched alkylene group having 1 to 12 carbon atoms are exemplified, specifically, for example, methylene group, ethylene group, n- propylene, isopropylene Group, n-butylene group, isobutylene group, sec-butylene group, tert-butylene group, n-pentylene group, isopentylene group, neopentylene group, tert-pentylene group and the like. The number of carbon atoms of the alkylene group represented by R ¹¹³ is preferably 1 or more and 10 or less, and more preferably 1 or more and 6 or less, from the viewpoint of compatibility and solubility.
Examples of the aryl group represented by Ar ¹¹⁴ include the same aryl groups represented by R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , and R ⁴⁷ in the general formula (IV). The same applies to the substituents that have.

In the general formula (IV), specific examples of the aralkyl group represented by R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , and R ⁴⁷ include, for example, a benzyl group, a methylbenzyl group, and a dimethylbenzyl group. , Phenylethyl group, methylphenylethyl group, phenylpropyl group, phenylbutyl group and the like.

In general formula (IV), examples of the alkyl group represented by R ⁴⁸ include a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 3 to 10 carbon atoms, and 3 or more carbon atoms. The cyclic alkyl group of 8 or less is mentioned.
Examples of the linear alkyl group include a methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, and n-nonyl. Group, n-decyl group and the like.
Examples of the branched alkyl group include isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, neopentyl group, tert-pentyl group, isohexyl group, sec-hexyl group, tert-hexyl group, Isoheptyl, sec-heptyl, tert-heptyl, isooctyl, sec-octyl, tert-octyl, isononyl, sec-nonyl, tert-nonyl, isodecyl, sec-decyl, tert-decyl Groups and the like.
Examples of the cyclic alkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group.

In general formula (IV), in the group represented by —L ¹¹¹ —O—R ¹¹² represented by R ⁴⁸ , L ¹¹¹ represents an alkylene group, and R ¹¹² represents an alkyl group.
^Examples of the alkylene group represented by L ¹¹¹ include linear or branched alkylene groups having 1 to 12 carbon atoms, and include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, and an isobutylene. Group, sec-butylene group, tert-butylene group, n-pentylene group, isopentylene group, neopentylene group, tert-pentylene group and the like.
Examples of the alkyl group represented by R ¹¹² include the same groups as the alkyl groups represented by R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , and R ⁴⁷ .

In general formula (IV), the aryl group represented by R ⁴⁸ may have a substituent or may not have a substituent, and examples thereof include a substituted or unsubstituted phenyl group. As a substituent which an aryl group has, a C1-C10 alkyl group, an alkoxy group, a halogen atom, etc. are mentioned, for example.
In addition, it is preferable from a soluble viewpoint that the aryl group is further substituted by the alkyl group or the alkoxy group. Examples of the alkyl group or alkoxy group substituted by the aryl group include the same groups as the alkyl group or alkoxy group represented by the above R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , and R ^47. It is done. For example, as an aryl group substituted with an alkyl group or an alkoxy group, a methylphenyl group (tolyl group), a dimethylphenyl group, an ethylphenyl group, a tert-butylphenyl group (such as p-tert-butylphenyl), methoxyphenyl, etc. Examples include a group (p-methoxyphenyl group and the like), an ethoxyphenyl group and the like.

In formula ^(IV), the aralkyl group represented by ^{R 48,} include groups represented by -R 115 ^{-Ar 116.} However, R ¹¹⁵ represents an alkylene group, Ar ¹¹⁶ , and an aryl group.
^Examples of the alkylene group represented by R ¹¹⁵ include linear or branched alkylene groups having 1 to 12 carbon atoms, and include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, and an isobutylene. Group, sec-butylene group, tert-butylene group, n-pentylene group, isopentylene group, neopentylene group, tert-pentylene group and the like.
Examples of the aryl group represented by Ar ¹¹⁶ include a phenyl group, a methylphenyl group, a dimethylphenyl group, and an ethylphenyl group.

Specific examples of the aralkyl group represented by R ⁴⁸ in the general formula (IV) include a benzyl group, a methylbenzyl group, a dimethylbenzyl group, a phenylethyl group, a methylphenylethyl group, a phenylpropyl group, and a phenylbutyl group. .

As the electron transport material of the general formula (IV), an electron transport material in which R ⁴⁸ represents a branched alkyl group or an aralkyl group having 5 to 10 carbon atoms is preferable from the viewpoint of high sensitivity and suppression of black spot generation, In particular, an electron transport material in which R ^{41 to} R ⁴⁷ each independently represents a hydrogen atom, a halogen atom, or an alkyl group, and R ⁴⁸ represents a branched alkyl group or an aralkyl group having 5 to 10 carbon atoms. preferable.

  Hereinafter, although the exemplary compound of the electron transport material represented by general formula (IV) is shown, it is not necessarily limited to this. In addition, the following exemplary compound numbers are described as an exemplary compound (IV-number) below. Specifically, for example, Exemplified Compound 15 is represented as “Exemplified Compound (IV-15)” below.

  Abbreviations in the above exemplified compounds have the following meanings. “N-Bu” represents an n-butyl group, “t-Bu” represents a tert-butyl group, “n-Oct” represents an n-octyl group, “Cl” represents a chlorine atom, and “Me” represents a methyl group. “MeO” represents a methoxy group, and “Ph” represents a phenyl group. Further, “*” represents a connecting portion.

In the general formula (V), R ⁵¹ , R ⁵² , R ⁵³ , and R ⁵⁴ each independently represent a halogen atom, an alkyl group, an alkoxy group, an aryl group, or an aralkyl group.

In the general formula (V), examples of the halogen atom represented by R ⁵¹ , R ⁵² , R ⁵³ , and R ⁵⁴ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these, a fluorine atom or a chlorine atom is preferable, and a chlorine atom is more preferable.

In the general formula (V), examples of the alkyl group represented by R ⁵¹ , R ⁵² , R ⁵³ , and R ⁵⁴ include a linear or branched alkyl group having 1 to 20 carbon atoms.
Examples of the linear alkyl group include a methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, and n-nonyl. Group, n-decyl group and the like.
Examples of the branched alkyl group include isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, neopentyl group, tert-pentyl group, isohexyl group, sec-hexyl group, tert-hexyl group, Isoheptyl group, sec-heptyl group, tert-heptyl group, isooctyl group, sec-octyl group, tert-octyl group, isononyl group, sec-nonyl group, tert-nonyl group, isodecyl group, sec-decyl group, tert-decyl Groups and the like. Among these, the carbon number of the alkyl group is more preferably 1 or more and 5 or less, and further preferably 1 or more and 4 or less.

In the general formula (V), examples of the alkoxy group represented by R ⁵¹ , R ⁵² , R ⁵³ , and R ⁵⁴ include an alkoxy group having 1 to 4 carbon atoms (preferably 1 to 3 carbon atoms). Examples include methoxy group, ethoxy group, propoxy group, butoxy group and the like.

  Hereinafter, although the exemplary compound of the electron transport material represented by general formula (V) is shown, it is not necessarily limited to this.

  As specific examples of the electron transport material, in addition to the electron transport material represented by the general formula (IV) and the electron transport material represented by the general formula (V), other electron transport materials include, for example, the following structural formula (ET Also included are compounds represented by -A) to (ET-E). Other electron transport materials may be used in combination with at least one of the electron transport materials represented by formulas (IV) and (V).

  The amount of the total electron transport material in the entire photosensitive layer is preferably 2% by mass or more and 30% by mass or less, and more preferably 5% by mass or more and 20% by mass or less in terms of the solid content ratio in the photosensitive layer. When the content of the electron transporting material is within this range, good electrical characteristics can be obtained, and the charge retention can be further improved.

The ratio of the hole transport material to the electron transport material is preferably 50/50 or more and 90/10 or less, more preferably 60/40 or more and 80/20 or less in terms of mass ratio (hole transport material / electron transport material). is there.
The “electron transport material” in this ratio is the total when two or more electron transport materials are used in combination, and the same applies to the hole transport material.

-Other additives-
The single-layer type photosensitive layer may contain other known additives such as a surfactant, an antioxidant, a light stabilizer, and a heat stabilizer. Further, when the single-layer type photosensitive layer is a surface layer, it may contain fluororesin particles, silicone oil and the like.

-Formation of single-layer type photosensitive layer-
The single-layer type photosensitive layer is formed using a photosensitive layer forming coating solution in which the above components are added to a solvent.
Solvents include aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, halogenated aliphatic hydrocarbons such as methylene chloride, chloroform and ethylene chloride, tetrahydrofuran and ethyl ether. And usual organic solvents such as cyclic or straight chain ethers. These solvents are used alone or in combination of two or more.

  As a method of dispersing particles (for example, charge generation material) in the coating solution for forming a photosensitive layer, a media disperser such as a ball mill, a vibration ball mill, an attritor, a sand mill, a horizontal sand mill, an agitator, an ultrasonic disperser, a roll mill, Medialess dispersers such as high-pressure homogenizers are used. Examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high-pressure state, and a penetration method in which a fine flow path is dispersed in a high-pressure state.

  Examples of the method for applying the photosensitive layer forming coating solution include a dip coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, and a curtain coating method.

  The film thickness of the single layer type photosensitive layer is preferably set in the range of 5 μm to 60 μm, more preferably 5 μm to 50 μm, and still more preferably 10 μm to 40 μm.

<Image forming apparatus (and process cartridge)>
The image forming apparatus according to the present embodiment includes an electrophotographic photosensitive member, a charging unit that charges the surface of the electrophotographic photosensitive member, and an electrostatic latent image formation that forms an electrostatic latent image on the surface of the charged electrophotographic photosensitive member. Means, developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image, and transfer means for transferring the toner image to the surface of the recording medium; Is provided. The electrophotographic photosensitive member according to the present embodiment is applied as the electrophotographic photosensitive member.

  The image forming apparatus according to the present embodiment includes an apparatus having fixing means for fixing a toner image transferred to the surface of a recording medium; direct transfer for directly transferring the toner image formed on the surface of the electrophotographic photosensitive member to the recording medium Type apparatus; intermediate transfer in which the toner image formed on the surface of the electrophotographic photosensitive member is primarily transferred onto the surface of the intermediate transfer member, and the toner image transferred onto the surface of the intermediate transfer member is secondarily transferred onto the surface of the recording medium. Type apparatus; apparatus provided with cleaning means for cleaning the surface of the electrophotographic photosensitive member after the toner image is transferred and before charging; after the toner image is transferred, the surface of the image carrier is irradiated with a charge-removing light before charging. A known image forming apparatus, such as an apparatus provided with a static elimination means for removing electricity; an apparatus provided with an electrophotographic photosensitive member heating member for increasing the temperature of the electrophotographic photosensitive member and reducing the relative temperature is applied.

  In the case of an intermediate transfer type apparatus, the transfer means includes, for example, an intermediate transfer body on which a toner image is transferred onto the surface, and a primary transfer that primarily transfers the toner image formed on the surface of the image holding body onto the surface of the intermediate transfer body. And a secondary transfer unit that secondarily transfers the toner image transferred onto the surface of the intermediate transfer member onto the surface of the recording medium.

  The image forming apparatus according to the present embodiment may be either a dry developing type image forming apparatus or a wet developing type (developing type using a liquid developer).

  In the image forming apparatus according to the present embodiment, for example, the part including the electrophotographic photosensitive member may have a cartridge structure (process cartridge) that is detachable from the image forming apparatus. As the process cartridge, for example, a process cartridge including the electrophotographic photosensitive member according to this embodiment is preferably used. In addition to the electrophotographic photosensitive member, the process cartridge may include at least one selected from the group consisting of a charging unit, an electrostatic latent image forming unit, a developing unit, and a transfer unit.

  Hereinafter, an example of the image forming apparatus according to the present embodiment will be described, but the present invention is not limited thereto. In addition, the main part shown to a figure is demonstrated and the description is abbreviate | omitted about others.

FIG. 2 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present embodiment.
As shown in FIG. 2, the image forming apparatus 100 according to the present embodiment includes a process cartridge 300 including an electrophotographic photosensitive member 7, an exposure device 9 (an example of an electrostatic latent image forming unit), and a transfer device 40 (primary. Transfer device) and an intermediate transfer member 50. In the image forming apparatus 100, the exposure device 9 is disposed at a position where the electrophotographic photosensitive member 7 can be exposed from the opening of the process cartridge 300, and the transfer device 40 is interposed between the electrophotographic photosensitive member via the intermediate transfer member 50. 7, and a part of the intermediate transfer member 50 is disposed in contact with the electrophotographic photosensitive member 7. Although not shown, it also has a secondary transfer device that transfers the toner image transferred to the intermediate transfer member 50 to a recording medium (for example, paper). The intermediate transfer member 50, the transfer device 40 (primary transfer device), and the secondary transfer device (not shown) correspond to an example of a transfer unit.

  A process cartridge 300 in FIG. 2 includes an electrophotographic photosensitive member 7, a charging device 8 (an example of a charging unit), a developing device 11 (an example of a developing unit), and a cleaning device 13 (an example of a cleaning unit) in a housing. I support it. The cleaning device 13 includes a cleaning blade (an example of a cleaning member) 131, and the cleaning blade 131 is disposed so as to contact the surface of the electrophotographic photosensitive member 7. The cleaning member may be a conductive or insulating fibrous member instead of the cleaning blade 131, and may be used alone or in combination with the cleaning blade 131.

  In FIG. 2, as an image forming apparatus, a fibrous member 132 (roll shape) for supplying the lubricant 14 to the surface of the electrophotographic photosensitive member 7 and a fibrous member 133 (flat brush shape) for assisting in cleaning are shown. Examples are provided, but these are arranged as necessary.

  Hereinafter, each configuration of the image forming apparatus according to the present embodiment will be described.

-Charging device-
As the charging device 8, for example, a contact type charger using a conductive or semiconductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube or the like is used. Further, a non-contact type roller charger, a known charger such as a scorotron charger using a corona discharge or a corotron charger may be used.

-Exposure device-
Examples of the exposure device 9 include optical system devices that expose the surface of the electrophotographic photoreceptor 7 with light such as semiconductor laser light, LED light, and liquid crystal shutter light in a predetermined image-like manner. The wavelength of the light source is within the spectral sensitivity region of the electrophotographic photosensitive member. As the wavelength of the semiconductor laser, near infrared having an oscillation wavelength near 780 nm is the mainstream. However, the present invention is not limited to this wavelength, and an oscillation wavelength laser in the 600 nm range or a laser having an oscillation wavelength of 400 nm to 450 nm as a blue laser may be used. In addition, a surface-emitting type laser light source that can output a multi-beam is also effective for color image formation.

-Development device-
Examples of the developing device 11 include a general developing device that performs development by bringing a developer into contact or non-contact with the developer. The developing device 11 is not particularly limited as long as it has the functions described above, and is selected according to the purpose. For example, a known developing device having a function of attaching a one-component developer or a two-component developer to the electrophotographic photosensitive member 7 using a brush, a roller, or the like can be used. Among these, those using a developing roller holding the developer on the surface are preferable.

  The developer used in the developing device 11 may be a one-component developer including a toner alone or a two-component developer including a toner and a carrier. Further, the developer may be magnetic or non-magnetic. A well-known thing is applied for these developers.

-Cleaning device-
As the cleaning device 13, a cleaning blade type device including a cleaning blade 131 is used.
In addition to the cleaning blade method, a fur brush cleaning method and a simultaneous development cleaning method may be employed.

-Transfer device-
As the transfer device 40, for example, a contact transfer charger using a belt, a roller, a film, a rubber blade, etc., or a known transfer charger such as a scorotron transfer charger using a corona discharge or a corotron transfer charger. Can be mentioned.

-Intermediate transfer member-
As the intermediate transfer member 50, a belt-like member (intermediate transfer belt) containing polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber or the like having semiconductivity is used. Further, as the form of the intermediate transfer member, a drum-like member may be used in addition to the belt-like member.

FIG. 3 is a schematic configuration diagram illustrating another example of the image forming apparatus according to the present embodiment.
An image forming apparatus 120 shown in FIG. 3 is a tandem multicolor image forming apparatus equipped with four process cartridges 300. In the image forming apparatus 120, four process cartridges 300 are arranged in parallel on the intermediate transfer member 50, and one electrophotographic photosensitive member is used for one color. The image forming apparatus 120 has the same configuration as that of the image forming apparatus 100 except that it is a tandem system.

  Note that the image forming apparatus 100 according to the present embodiment is not limited to the above configuration, and is, for example, a cleaning device around the electrophotographic photosensitive member 7 and downstream of the transfer device 40 in the rotation direction of the electrophotographic photosensitive member 7. The first toner neutralizing device may be provided on the upstream side of the rotation direction of the electrophotographic photosensitive member with respect to 13 so that the polarity of the remaining toner is aligned and easily removed with a cleaning brush. Alternatively, a configuration may be adopted in which a second static elimination device for neutralizing the surface of the electrophotographic photosensitive member 7 is provided on the downstream side in the rotation direction of the electrophotographic photosensitive member and on the upstream side in the rotational direction of the electrophotographic photosensitive member relative to the charging device 8. .

  In addition, the image forming apparatus 100 according to the present embodiment is not limited to the above-described configuration, and a well-known configuration, for example, a direct transfer type image forming apparatus that directly transfers a toner image formed on the electrophotographic photosensitive member 7 to a recording medium. It may be adopted.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

[Formation of undercoat layer]
(Preparation of undercoat layer 1)
40 parts by mass of the specific charge transport material I-8, 20 parts by mass of I-16 are dissolved in a mixed solvent of 400 parts by mass of tetrahydrofuran and 400 parts by mass of 2-butanol, and NACURE 2500 (manufactured by King Industries, Inc., block acid catalyst) is 0. .3 parts by mass was added to obtain a coating solution for forming an undercoat layer. This coating solution was applied onto an aluminum substrate by a dip coating method, followed by drying and curing at 160 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 0.3 μm. This is the undercoat layer 1.

(Preparation of undercoat layer 2)
In the preparation of the undercoat layer 1, the undercoat was performed except that I-8 was 38 parts by mass, I-16 was 18 parts by mass, and 4 parts by mass of a resol type phenol resin (PL-4852, manufactured by Gunei Chemical Co., Ltd.) was added. The undercoat layer was obtained in the same manner as the production of the layer 1. This is the undercoat layer 2.

(Preparation of undercoat layer 3)
In preparation of the undercoat layer 2, instead of a resol type phenol resin (PL-4852, manufactured by Gunei Chemical Co., Ltd.), a blocked isocyanate (Sumidur BL-3175, manufactured by Sumitomo Bayer Urethane Co., Ltd.) is used instead of an acid catalyst. The undercoat layer forming coating solution was prepared in the same manner as the preparation of the undercoat layer 1 except that 0.005 parts by mass of dioctyltin dilaurate was added. This coating solution was applied onto an aluminum substrate by a dip coating method, followed by drying and curing at 190 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 0.3 μm. This is the undercoat layer 3.

(Preparation of undercoat layer 4)
1. Zinc oxide: (volume average particle size 70 nm: manufactured by Teika: specific surface area value 15 m ² / g) 100 parts by mass of 500 parts by mass of toluene are mixed with stirring, and a silane coupling agent (KBE603: manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by mass was added and stirred for 2 hours. Thereafter, toluene was distilled off under reduced pressure and baked at 150 ° C. for 3 hours to obtain a silane coupling agent surface-treated zinc oxide pigment.
10 parts by mass of this zinc oxide is added to 100 parts by mass of the coating liquid for adding the dioctyltin dilaurate in the coating liquid for forming the undercoat layer prepared in the preparation of the undercoat layer 3, and dispersed in a sand mill using 1 mmφ glass beads. And a milky white dispersion was obtained. To this, 0.005 part by mass of dioctyltin dilaurate was added to obtain a coating solution for forming an undercoat layer. This coating solution was applied onto an aluminum substrate by a dip coating method, followed by drying and curing at 180 ° C. for 45 minutes to obtain an undercoat layer having a thickness of 0.5 μm. This is the undercoat layer 4.

(Preparation of undercoat layer 5)
The subbing layer 1 was prepared under the same conditions except that I-8 was 38 parts by mass, I-16 was 18 parts by mass, and 6 parts by mass of methylated benzoguanamine resin (BL-60, manufactured by Sanwa Chemical) was added. The undercoat layer was obtained in the same manner as the production of the layer 1. This is the undercoat layer 5.

(Preparation of undercoat layer 6)
100 parts by mass of zinc oxide particles (average particle size 60 nm: MZ-150, manufactured by Teica), 10 parts by mass of a 10% by weight toluene solution of γ-aminopropyltriethoxysilane as a silane coupling agent, and 200 parts by mass of toluene Were mixed, stirred, and refluxed for 2 hours. Thereafter, toluene was distilled off under reduced pressure, and a baking treatment was performed at 135 ° C. for 2 hours to obtain aminosilane-treated zinc oxide particles surface-treated with aminosilane.
7 mass parts of alcohol-soluble 6/12/66/610 copolymer nylon resin (Amilan CM8000, manufactured by Toray Industries, Inc.) and 5 mass parts of aminosilane-treated zinc oxide particles were dissolved and dispersed in 90 mass parts of methanol. A coating solution for forming a drawing layer was prepared. This coating solution was applied onto an aluminum substrate by a dip coating method and dried at a temperature of 100 ° C. for 30 minutes to obtain an undercoat layer having a thickness of 1 μm. This is the undercoat layer 6.

(Preparation of undercoat layer 7)
100 parts by mass of zinc oxide particles (average particle size 70 nm: MZ-200 manufactured by Teika Co., Ltd .: specific surface area value 15 m ² / g) is stirred and mixed with 500 parts by mass of toluene, and a silane coupling agent (KBM-573, Shin-Etsu Chemical Co., Ltd.). (Product) 1.3 parts by mass was added and stirred for 2 hours. Thereafter, toluene was distilled off under reduced pressure, and baking was performed at 120 ° C. for 3 hours to obtain silane coupling agent surface-treated zinc oxide particles.
60 parts by mass of the surface-treated zinc oxide particles, 13.5 parts by mass of a curing agent (blocked isocyanate Sumijoule 3175, manufactured by Sumitomo Bayer Urethane Co., Ltd.) and a butyral resin (ESLEC BM-1, manufactured by Sekisui Chemical Co., Ltd.) A solution in which 15 parts by mass was dissolved in 150 parts by mass of methyl ethyl ketone was dispersed for 2 hours with a sand mill using 1 mmφ glass beads to obtain a dispersion.
Dioctyltin dilaurate: 0.005 parts by mass and silicone resin particles (Tospearl 145, manufactured by Momentive Performance Materials): 20 parts by mass are added as catalysts to the resulting dispersion to obtain an undercoat layer coating solution. It was. This coating solution was applied onto an aluminum substrate by a dip coating method, followed by drying and curing at 160 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 1 μm. This is the undercoat layer 7.

(Preparation of undercoat layer 8)
30 parts by mass of the specific charge transport material I-16, 16 parts by mass of I-26, 400 parts by mass of tetrahydrofuran, 5 parts by mass of methylated melamine resin (MW-390, manufactured by Sanwa Chemical Co., Ltd.) are 400 parts by mass of 2-butanol. After dissolving in a mixed solvent, 0.3 part by mass of NACURE 5225 (manufactured by King Industries, Inc., block acid catalyst) was added to obtain a coating solution for forming an undercoat layer. This coating solution was applied onto an aluminum substrate by a dip coating method, followed by drying and curing at 160 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 0.2 μm. This is the undercoat layer 8.

<Example 1>
[Formation of single-layer type photosensitive layer]
X-ray diffraction spectrum Bragg angles (2θ ± 0.2 °) using CuKα characteristic X-rays as charge generation materials are at least 7.3 °, 16.0 °, 24.9 °, and 28.0 ° 1.2 parts by mass of hydroxygallium phthalocyanine having a diffraction peak in the above, 49 parts by mass of a copolymer-type polycarbonate resin (viscosity average molecular weight 50,000) represented by the following formula (P) as a binder resin, 250 parts by mass of tetrahydrofuran, toluene A mixture consisting of 20 parts by mass was dispersed in a sand mill for 3 hours using glass beads having a diameter of 1 mmφ. The glass beads are separated by filtration, and 30 parts by mass of the above-described hole transport material (HT-7) and 8 parts by mass of the electron transport material (IV-10) represented by the above general formula (IV) are obtained in the obtained dispersion. Part, 1 part by mass of the electron transport material (V-2) represented by the general formula (V), 0.001 part by mass of silicone oil KP340 (manufactured by Shin-Etsu Chemical Co., Ltd.), and stirring overnight (12 hours) Thus, a coating solution for forming a photosensitive layer was obtained. This photosensitive layer forming coating solution was dip-coated on the undercoat layer 1 and dried at 125 ° C. for 1 hour to form a single-layer type photosensitive layer having a film thickness of 19 μm, whereby the photoreceptor 1 was produced. . In addition, the number in Formula (P) shows content (molar ratio) of each structural unit.

<Examples 2 to 10, Comparative Examples 1 to 5>
In accordance with Table 1, the photoreceptors 2 to 10 and the photoreceptor C1 were the same as in Example except that the type of the undercoat layer, the kind of the electron transport material used for the photosensitive layer, and the kind of the hole transport material were changed. ~ C5 was obtained.

[Evaluation]
(Spot quality evaluation)
Under an environment of room temperature 30 ° C. and humidity 85%, 12,000 20% halftone images were formed using Brother HL-2360D, and 10 more 20% halftone images were formed 10 hours later. The 10th image of 10 sheets formed after 10 hours was visually evaluated, and the presence or absence of black spots was evaluated according to the following criteria. The results are shown in Table 1.
A: No black spots occur B: 9 or less black spots, acceptable level in image quality C: 10 or more black spots occur, causing a problem in actual use.

(Electrical characteristics evaluation)
Under the conditions of black spot image quality evaluation, the difference ΔV between the surface potential of the photoconductor in the initial stage (before 20% halftone image formation) and the surface potential of the photoconductor after 12,000 sheets were formed was evaluated. The results are shown in Table 1.
A: ΔV is less than 50V, no problem at all.
B: ΔV is 50 V or more and less than 80 V, and is an allowable range.
C: Level at which ΔV is 80V or more, causing image quality problems

The details of the abbreviations in Table 1 are as follows.
Specific CTM: Specific charge transporting material (charge transporting material having at least one substituent selected from the group consisting of —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH)
・ CGM: Charge generation material ・ ETM: Electron transport material ・ HTM: Hole transport material

I-8: Illustrative compound (I-8) of the specific charge transporting material of the general formula (I)
I-16: Exemplary compound (I-16) of the specific charge transporting material of the general formula (I)
* I-26: Illustrative compound (I-26) of the specific charge transporting material of the general formula (I)

“HOGaPc”: Bragg angle (2θ ± 0.2 °) of X-ray diffraction spectrum using CuKα characteristic X-ray is at least 7.3 °, 16.0 °, 24.9 °, 28.0 ° V-type hydroxygallium phthalocyanine pigment having a diffraction peak at “ClGaPc”: Bragg angle (2θ ± 0.2 °) of X-ray diffraction spectrum using CuKα characteristic X-ray is at least 7.4 °, 16.6 ° Chlorogallium phthalocyanine pigment having diffraction peaks at 25.5 ° and 28.3 ° (maximum peak wavelength in spectral absorption spectrum in wavelength range of 600 nm to 900 nm = 780 nm, average particle size = 0.15 μm, maximum Particle size = 0.2 μm, specific surface area value = 56 m ² / g)

IV-3: Exemplary compound (IV-3) of an electron transport material of the general formula (IV)
IV-9: Exemplary compound (IV-9) of an electron transport material of the general formula (IV)
IV-10: Exemplary compound (IV-10) of an electron transport material of the general formula (IV)
IV-11: Exemplary compound (IV-11) of an electron transport material of the general formula (IV)
V-2: Exemplary compound (V-2) of electron transport material of general formula (V)
V-6: Exemplary compound (V-6) of the electron transport material of the general formula (V)
ET-B: electron transport material (ET-B) represented by structural formula (ET-B)
ET-C: electron transport material (ET-C) represented by structural formula (ET-C)
HT-2: hole transport material (HT-2) represented by structural formula (HT-2)
HT-4: hole transport material (HT-4) represented by structural formula (HT-4)
HT-7: hole transport material (HT-7) represented by structural formula (HT-7)

DESCRIPTION OF SYMBOLS 1 Undercoat layer, 2 Photosensitive layer, 3 Conductive substrate, 7 Electrophotographic photoreceptor, 8 Charging device, 9 Exposure device, 11 Developing device, 13 Cleaning device, 14 Lubricant, 40 Transfer device, 50 Intermediate transfer body, 100 Image forming apparatus, 120 Image forming apparatus, 131 Cleaning blade, 132 Fibrous member (roll shape), 133 Fibrous member (flat brush shape), 300 Process cartridge

Claims (7)

A conductive substrate;
A charge transporting material having at least one substituent selected from the group consisting of —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH, which is an undercoat layer provided on the conductive substrate An undercoat layer that is a cured product of a composition containing
A single-layer type photosensitive layer provided on the undercoat layer, the photosensitive layer comprising a binder resin, a charge generation material, a hole transport material, and an electron transport material;
An electrophotographic photosensitive member having: The electrophotographic photosensitive member according to claim 1, wherein the charge transporting material is a compound represented by the following general formula (I).
(I) F - ((- R 1 -O) n1 R 2 -Y) n2
(In general formula (I), F is an organic group derived from a compound having a hole transporting ability, R ¹ and R ² are each independently a linear or branched alkylene group having 1 to 5 carbon atoms. N1 represents 0 or 1, n2 represents an integer of 1 to 4, O represents oxygen, and Y independently represents —OH, —OCH ₃ , —NH ₂ , —SH, or — COOH is shown.)   The electrophotographic photosensitive member according to claim 1, wherein the composition further contains at least one curable compound selected from a phenol compound, a melamine compound, a guanamine compound, and an isocyanate compound.   The electrophotographic photoreceptor according to claim 1, wherein the composition further contains metal oxide particles.   The electrophotographic photoreceptor according to claim 1, wherein the charge generation material is at least one selected from hydroxygallium phthalocyanine pigments and chlorogallium phthalocyanine pigments. The electrophotographic photoreceptor according to any one of claims 1 to 5,
A process cartridge that can be attached to and detached from an image forming apparatus. The electrophotographic photosensitive member according to any one of claims 1 to 5,
Charging means for charging the surface of the electrophotographic photosensitive member;
An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image;
Transfer means for transferring the toner image to the surface of the recording medium;
An image forming apparatus comprising: