JP5772451B2 - Electrophotographic photosensitive member and image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photoreceptor and an image forming apparatus.

  In recent years, organic photoconductors (OPCs) have good performance and are widely used in copiers, facsimiles, laser printers, and composite machines in place of inorganic photoreceptors because of their various advantages. . The reason for this is that organic photoreceptors have a wide light absorption wavelength range, optical characteristics such as the amount of absorption, electrical characteristics such as high sensitivity and stable charging characteristics, a wide range of material selection, and manufacturing. It is excellent in ease of use, low cost, non-toxicity and the like.

  However, the organic photoreceptor contains a low-molecular charge transport material, an inert polymer, etc. as a main component in the charge transport layer, so that it is generally soft and can be used repeatedly for a long time in an electrophotographic process, depending on a development system or a cleaning system. There is a problem that mechanical load is generated and mechanical durability such as wear resistance and damage resistance is inferior. Such wear, damage, etc. of the organic photoreceptor has a problem of deteriorating electrical characteristics such as deterioration of sensitivity and chargeability and generating abnormal images such as image density reduction and background stains. Further, there is a problem that scratches in which wear occurs locally cause streak-like stain images due to poor cleaning.

  Therefore, for the purpose of improving the mechanical durability of the organic photoreceptor, it has been proposed to form a charge transport layer having a three-dimensional crosslinked polymer on the organic photoreceptor (see, for example, Patent Documents 1 to 9).

  For example, a charge transport layer having a three-dimensional crosslinked polymer obtained by radical polymerization of a hole transporting compound having two or more polymerizable functional groups in the same molecule by ultraviolet irradiation, electron beam irradiation or the like has been proposed ( Patent Document 1). However, this proposed technique requires a large-scale apparatus that performs ultraviolet irradiation, electron beam irradiation, and the like, which is problematic in terms of productivity. Further, there is a problem that the charge transporting compound deteriorates due to ultraviolet irradiation, electron beam irradiation, etc., and the electrical characteristics of the photoreceptor deteriorate.

  In addition, a charge transport layer having a polymer obtained by three-dimensionally cross-linking a charge transport compound having a polar group such as a hydroxyl group has been proposed (see Patent Documents 5 to 8). However, this proposed technique has a problem in that charge reduction occurs because polar groups such as hydroxyl groups of the charge transporting compound remain in the three-dimensional crosslinked polymer. In addition, there is a problem in that the image density in a high-temperature and high-humidity environment tends to decrease and the environmental stability is not sufficient. In addition, there is a problem that the image density is easily lowered by exposure to NOx gas or the like generated by the charger, and the gas stability is not sufficient.

  In addition, a charge transport layer having a three-dimensional cross-linked polymer obtained by curing a compound in which a polar group such as a hydroxyl group of a charge transport compound is blocked and a reactive species such as melamine has been proposed (see Patent Document 9). . However, this proposed technique can prevent the polar group from remaining, but has a problem in that the reactivity between the blocked polar group and the reactive species is poor and the mechanical durability is poor.

  Therefore, an electrophotographic photosensitive member having excellent mechanical durability, electrical characteristics, environmental stability, and gas resistance stability has not been provided yet, and the development is strongly demanded at present. .

  This invention is made | formed in view of this present condition, and makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, an object of the present invention is to provide an electrophotographic photoreceptor having excellent mechanical durability, electrical characteristics, environmental stability, and gas resistance.

  As a result of intensive studies to achieve the above object, the present inventors have used [(tetrahydro-2H-pyran-] as an aromatic ring of a highly reactive charge transporting compound that uses vinylsulfonic acid as a curing catalyst. By including a three-dimensional cross-linked polymer obtained by polymerization reaction of a compound having two or more 2-yl) oxy] methyl groups in the outermost surface layer of the photosensitive layer, excellent mechanical durability, electrical characteristics, and environmental stability It has been found that an electrophotographic photosensitive member that has both stability and gas resistance stability can be obtained.

This invention is based on the said knowledge by the present inventors, and as means for solving the said subject, it is as follows. That is,
The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having a conductive support and at least a photosensitive layer on the conductive support, the electrophotographic photoreceptor having an outermost surface layer, From the compound in which the outermost surface layer uses vinylsulfonic acid as a curing catalyst and has three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound, (Tetrahydro-2H-pyran-2-yl) oxy] has a three-dimensional crosslinked polymer formed by polymerization by a reaction in which a part of the methyl group is cut off and eliminated.

  According to the present invention, various conventional problems can be solved, and an electrophotographic photoreceptor having excellent mechanical durability, electrical characteristics, environmental stability, and gas resistance stability can be provided.

FIG. 1 is a schematic view showing the layer structure of the electrophotographic photosensitive member according to the first embodiment of the present invention. FIG. 2 is a schematic view showing the layer structure of the electrophotographic photosensitive member according to the second embodiment of the present invention. FIG. 3 is a schematic view showing the layer structure of an electrophotographic photosensitive member according to the third embodiment of the present invention. FIG. 4 is a schematic view showing a layer structure of an electrophotographic photosensitive member according to the fourth embodiment of the present invention. FIG. 5 is a schematic view showing the layer structure of an electrophotographic photosensitive member according to the fifth embodiment of the present invention. FIG. 6 is a schematic view showing an example of the image forming apparatus and the electrophotographic process of the present invention. FIG. 7 is a schematic view showing an example of the tandem full-color image forming apparatus of the present invention. FIG. 8 is a schematic diagram illustrating an example of a process cartridge according to the present invention. FIG. 9 is an infrared absorption spectrum diagram (KBr tablet method) of the compound obtained in Synthesis Example 1, the horizontal axis indicates the wave number (cm ⁻¹ ), and the vertical axis indicates the transmittance (%). FIG. 10 is an infrared absorption spectrum diagram (KBr tablet method) of the compound obtained in Synthesis Example 2, the horizontal axis indicates the wave number (cm ⁻¹ ), and the vertical axis indicates the transmittance (%). FIG. 11 is an infrared absorption spectrum diagram (KBr tablet method) of the compound obtained in Synthesis Example 3, the horizontal axis indicates the wave number (cm ⁻¹ ), and the vertical axis indicates the transmittance (%). FIG. 12 is an infrared absorption spectrum diagram (KBr tablet method) of the compound obtained in Synthesis Example 4. The horizontal axis indicates the wave number (cm ⁻¹ ), and the vertical axis indicates the transmittance (%). FIG. 13 is an infrared absorption spectrum diagram (KBr tablet method) of the compound obtained in Synthesis Example 5, the horizontal axis indicates the wave number (cm ⁻¹ ), and the vertical axis indicates the transmittance (%). FIG. 14 is an infrared absorption spectrum diagram (KBr tablet method) of the compound obtained in Synthesis Example 6, the horizontal axis indicates the wave number (cm ⁻¹ ), and the vertical axis indicates the transmittance (%). FIG. 15 is an infrared absorption spectrum diagram (KBr tablet method) of the compound obtained in Synthesis Example 7, the horizontal axis indicates the wave number (cm ⁻¹ ), and the vertical axis indicates the transmittance (%). FIG. 16 is an infrared absorption spectrum diagram (KBr tablet method) of the compound obtained in Synthesis Example 8, the horizontal axis indicates the wave number (cm ⁻¹ ), and the vertical axis indicates the transmittance (%). FIG. 17 is an infrared absorption spectrum diagram (KBr tablet method) of the compound obtained in Synthesis Example 9, where the horizontal axis indicates wave number (cm ⁻¹ ) and the vertical axis indicates transmittance (%). FIG. 18 is an infrared absorption spectrum diagram (KBr tablet method) of the compound obtained in Synthesis Example 10, the horizontal axis indicates the wave number (cm ⁻¹ ), and the vertical axis indicates the transmittance (%). 19 is an infrared absorption spectrum diagram (KBr tablet method) of the compound obtained in Synthesis Example 11, the horizontal axis indicates the wave number (cm ⁻¹ ), and the vertical axis indicates the transmittance (%).

(Electrophotographic photoreceptor)
The electrophotographic photoreceptor of the present invention has a conductive support and at least a photosensitive layer on the conductive support, and further has other layers as necessary.

<Conductive support>
The conductive support is not particularly limited as long as it has a volume resistance of 10 ¹⁰ Ω · cm or less, and can be appropriately selected according to the purpose. An endless belt (such as an endless nickel belt or an endless stainless steel belt) disclosed in Japanese Patent Laid-Open No. 52-36016 may be used.

  There is no restriction | limiting in particular as a formation method of the said electroconductive support body, According to the objective, it can select suitably, For example, a metal (aluminum, nickel, chromium, nichrome, copper, gold | metal | money, silver, platinum etc.) or a metal A method in which an oxide (tin oxide, indium oxide, etc.) is deposited or sputtered and coated on a support (film, cylindrical plastic, paper, etc.); metal (aluminum, aluminum alloy, nickel, For example, a method of extruding a plate of stainless steel, etc., performing drawing, etc., and performing surface treatment (cutting, superfinishing, polishing, etc. after forming a blank), and the like.

The conductive support may be provided with a conductive layer on the conductive support.
The method for forming the conductive layer is not particularly limited and may be appropriately selected according to the purpose. For example, the conductive layer and the binder resin may be dispersed or dissolved in a solvent as necessary. A method of forming the applied coating liquid on the conductive support; a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, and Teflon (registered trademark); Examples include a method of forming using a heat-shrinkable tube containing conductive powder.

  There is no restriction | limiting in particular as said electroconductive powder, According to the objective, it can select suitably, For example, carbon powder, acetylene black; Metal powder, such as aluminum, nickel, iron, nichrome, copper, zinc, silver; Examples thereof include conductive tin oxide and metal oxide powders such as ITO.

  The binder resin used for the conductive layer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polystyrene resin, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-anhydrous Maleic acid copolymer, polyester resin, polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate resin, polyvinylidene chloride resin, polyarylate resin, phenoxy resin, polycarbonate resin, cellulose acetate resin, ethyl cellulose resin, Examples include polyvinyl butyral resin, polyvinyl formal resin, polyvinyl toluene resin, poly-N-vinyl carbazole resin, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin, and the like.

  There is no restriction | limiting in particular as a solvent used for the said electroconductive layer, According to the objective, it can select suitably, For example, tetrahydrofuran, a dichloromethane, methyl ethyl ketone, toluene etc. are mentioned.

<Photosensitive layer>
The photosensitive layer is not particularly limited as long as it has an outermost surface layer on the outermost surface, and can be appropriately selected according to the purpose. However, at least a charge generation layer, a charge transport layer, an outermost surface layer (crosslinked type) A photosensitive layer having a charge transport layer) in this order and, if necessary, other layers is preferred.

<< Outermost surface layer (crosslinked charge transport layer) >>
The outermost surface layer is the outermost surface layer of the photosensitive layer and is also referred to as a crosslinkable charge transport layer.
The outermost surface layer (crosslinked charge transport layer) uses vinyl sulfonic acid as a curing catalyst, and has three [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transport compound. It has a three-dimensional cross-linked polymer formed by polymerization by a reaction in which a part of the [(tetrahydro-2H-pyran-2-yl) oxy] methyl group is cut off and eliminated from the compound having the above.

There is no restriction | limiting in particular as content of the said vinyl sulfonic acid in the said outermost surface layer, Although it can select suitably according to the objective, 0.01 mass%-1.0 with respect to the said outermost surface layer. % By mass is preferable, 0.05% by mass to 0.5% by mass is more preferable, and 0.1% by mass to 0.2% by mass is particularly preferable. When the content is less than 0.01% by mass, mechanical durability (wear resistance) may be inferior due to insufficient crosslinking reaction, and when the content exceeds 1.0% by mass, the image in a high-temperature and high-humidity environment. Defects may occur. When the content is within the particularly preferable range, it is advantageous in terms of both mechanical durability (wear resistance) and image quality.
Here, when the outermost surface layer has only the three-dimensional crosslinked polymer and the vinyl sulfonic acid, the content of the vinyl sulfonic acid on the outermost surface is the sum of the three-dimensional crosslinked polymer and the vinyl sulfonic acid. It can also be called content of the said vinyl sulfonic acid with respect to quantity.
In addition, content of the said vinyl sulfonic acid in the said outermost surface layer can be measured by the sulfur elemental analysis by TOF-SIMS.

-3D cross-linked polymer
The three-dimensional crosslinked polymer is a polymer having a three-dimensional network structure.
The three-dimensional crosslinked polymer uses a vinyl sulfonic acid as a curing catalyst, and includes a compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound. [(Tetrahydro-2H-pyran-2-yl) oxy] formed by polymerization by a reaction in which a part of the methyl group is cut off and eliminated.

  In other words, the three-dimensional crosslinked polymer uses vinyl sulfonic acid as a curing catalyst, and has three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound. A part of the [(tetrahydro-2H-pyran-2-yl) oxy] methyl group breaks away and bonds to each other to form a macromolecule in a three-dimensional network. The [(tetrahydro-2H-pyran-2-yl) oxy] methyl group is a polymer that remains unreacted.

  In the present invention, a compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on an aromatic ring of a charge transporting compound is insoluble in an organic solvent or the like by using a suitable curing catalyst. This is based on the finding that a three-dimensional crosslinked film having a high density can be formed.

  Furthermore, by using vinyl sulfonic acid as a curing catalyst, the resulting three-dimensional cross-linked polymer has particularly excellent mechanical durability (wear resistance, scratch resistance, etc.) and excellent electrical properties (charging stability, sensitivity). It has been found that it has excellent environmental stability (especially under high temperature and high humidity) and excellent gas stability (NOx resistance, etc.).

Vinyl sulfonic acid is a sulfonic acid compound composed only of a vinyl group and a sulfonic acid group, and is a compound having a small molecular weight represented by CH ₂ ═CHSO ₃ H. Therefore, compared with other sulfonic acid compounds such as p-toluenesulfonic acid, naphthalenesulfonic acid, dodecylbenzenesulfonic acid, etc., a small amount of addition may be used as a curing catalyst. In addition, since the structure is simple, side reactions of the vinyl sulfonic acid itself hardly occur, and the side effect on the photoreceptor characteristics provided by the residual curing catalyst can be reduced.

  It has been conventionally known that a (tetrahydro-2H-pyran-2-yl) group is used as a hydroxyl-protecting group. For example, it is also described in JP-A-2006-084711. Although cured products obtained by reacting a compound having a (tetrahydro-2H-pyran-2-yl) group as a protecting group with a reactive species such as melamine have been studied, (tetrahydro-2H-pyran- An example of forming a crosslinked film by a compound having a 2-yl) group alone is not known.

Usually, the idea of a protecting group reminds us that the protecting group is removed and reacts. Therefore, when it is considered that the [(tetrahydro-2H-pyran-2-yl) oxy] methyl group changes to a methylol group and reacts, the obtained three-dimensional crosslinked polymer is the same as the crosslinked polymer of the methylol body.
However, as a result of the study by the present inventors, in the present invention, the compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound passes through the methylol group. It turns out that it reacts without doing. Therefore, the [(tetrahydro-2H-pyran-2-yl) oxy] methyl group remains in the unreacted part. Thus, the presence of [(tetrahydro-2H-pyran-2-yl) oxy] methyl group in the crosslinked polymer also affects the film properties of the outermost surface layer obtained. That is, the three-dimensional crosslinked polymer obtained from a compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound is compared with a crosslinked cured product of a methylol body. There is a merit that gas permeability affecting gas resistance is small.

  Thus, a three-dimensional cross-linked polymer formed by a polymerization reaction of a compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound, and vinyl By using a layer containing a three-dimensional cross-linked polymer obtained by using sulfonic acid as a curing catalyst for the polymerization reaction as the outermost surface layer of the electrophotographic photoreceptor, excellent electrical characteristics (for example, charging stability) and resistance An electrophotographic photosensitive member having gas stability (for example, NOx resistance) and excellent in mechanical durability and environmental stability can be obtained.

  Further, since the three-dimensional crosslinked polymer is usually a cured product of only a charge transporting compound, it exhibits good charge transporting properties and yet does not directly contribute to charge transport [(tetrahydro-2H-pyran-2-yl) Electrically inactive parts such as oxy] methyl groups are also appropriately incorporated, so that they have excellent charging stability and do not contain polar groups such as hydroxyl groups. Also excellent.

The three-dimensional crosslinked polymer exhibits particularly excellent mechanical properties when insoluble in a solvent. Therefore, it is preferable that the three-dimensional crosslinked polymer is insoluble in a solvent, particularly insoluble in tetrahydrofuran.
A compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound is well dissolved in tetrahydrofuran. However, when this compound reacts to form bonds in a three-dimensional network, the resulting three-dimensional crosslinked polymer is no longer soluble in tetrahydrofuran and other solvents.
Therefore, the fact that the three-dimensional cross-linked polymer is insoluble in tetrahydrofuran indicates that the surface of the electrophotographic photosensitive member is a macromolecule and has an integrated structure, and therefore has high mechanical properties. Demonstrate. Here, insoluble means a state in which the three-dimensional crosslinked polymer does not disappear even when immersed in tetrahydrofuran. Furthermore, it is preferable that no trace remains even when rubbed with a cotton swab moistened with tetrahydrofuran.
Thus, by being insoluble in the solvent, adhesion of foreign matter to the electrophotographic photosensitive member can be prevented, and generation of scratches on the surface of the electrophotographic photosensitive member due to foreign matter adhesion can be prevented.

The three-dimensional crosslinked polymer can be obtained by, for example, adding vinyl sulfonic acid to a compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound and heating the compound. It was obtained by a polymerization reaction.
By heating using vinyl sulfonic acid as a curing catalyst, the condensation reaction can proceed at a practical speed, and an outermost surface layer having excellent surface smoothness can be formed. When the surface smoothness is extremely deteriorated, the cleaning property of the toner is deteriorated, and an abnormal image is caused and high-quality printing cannot be performed. Therefore, it is possible to form a three-dimensional crosslinked polymer having excellent surface smoothness by heating at a suitable temperature using a suitable curing catalyst, and electrophotographic photosensitive film containing the three-dimensional crosslinked polymer in the outermost surface layer of the photosensitive layer. The body will be able to print higher quality images over a long period of time.

--A compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound--
A compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound is subjected to a polymerization reaction using vinyl sulfonic acid as a curing catalyst. Tetrahydro-2H-pyran-2-yl) oxy] methyl group is partially removed to form the three-dimensional crosslinked polymer.

  The charge transporting compound used in the compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups in the aromatic ring of the charge transporting compound is not particularly limited and may be selected depending on the purpose. For example, a compound having a triarylamine structure, an aminobiphenyl structure, a benzidine structure, an aminostilbene structure, a naphthalenetetracarboxylic acid diimide structure, a benzhydrazine structure, or the like can be given.

  The compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound is not particularly limited and may be appropriately selected depending on the intended purpose. The compound represented by the following general formula (1), the compound represented by the following general formula (2), and the compound represented by the following general formula (3) are preferable. These may be used alone or in combination of two or more.

--- Compound represented by the general formula (1) ---
The compound represented by the following general formula (1) has a high proportion of [(tetrahydro-2H-pyran-2-yl) oxy] methyl group per molecular weight, and thus can form a three-dimensional crosslinked polymer having a high crosslinking density. Therefore, it is possible to provide an electrophotographic photosensitive member having high hardness and high scratch resistance.
However, in said general formula (1), Ar < ₁ >, Ar < ₂ > and Ar < ₃ > represent the C6-C18 bivalent aromatic hydrocarbon group which may have an alkyl group as a substituent.

In the general formula (1), examples of the alkyl group in Ar ₁ , Ar ₂ and Ar ₃ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. Examples include linear or branched aliphatic alkyl groups.
In the general formula (1), examples of the aromatic hydrocarbon having 6 to 18 carbon atoms in Ar ₁ , Ar ₂ and Ar ₃ include, for example, benzene, naphthalene, fluorene, phenanthrene, anthracene, pyrene, biphenyl, terphenyl, Examples include stilbene.

There is no restriction | limiting in particular as a compound represented by the said General formula (1), Although it can select suitably according to the objective, It is represented by the following general formula (1-1) at the point which is excellent in a crosslinking reaction. Compounds are preferred.
However, in said general formula (1-1), R < ₁ >, R < ₂ > and R < ₃ > may be the same or different, and represent a hydrogen atom, a methyl group, or an ethyl group, l, n and m represent an integer of 1 to 4.

  The compound represented by the general formula (1-1) is particularly excellent among the compounds represented by the general formula (1), and the mutual polymerization reactivity is particularly good. Although there remains an unclear part about the polymerization reaction between the [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups, it binds to the [(tetrahydro-2H-pyran-2-yl) oxy] methyl group. When the aromatic ring to be formed is a benzene ring having a tertiary amino group, the progress is the fastest, and a crosslinked protective layer having a higher crosslinking density can be formed.

There is no restriction | limiting in particular as a compound represented by the said General formula (1), According to the objective, it can select suitably, For example, following structural formula (1-1)-(1-12) is mentioned, for example. The compound etc. which are represented by these are mentioned. In addition, the compounds represented by the following structural formulas (1-1) to (1-8) are also specific examples of the compounds represented by the general formula (1-1).
However, in the structural formulas, Me represents a methyl group, and Et represents an ethyl group.

--- Compound represented by formula (2) ---
The compound represented by the following general formula (2) has four [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound, and is non-conjugated linked. also it has a moderate molecular mobility that it has a X ₁ group, some of the [(tetrahydro -2H- pyran-2-yl) oxy] easily form a three-dimensional crosslinked polymer leaving a methyl group The finished three-dimensional cross-linked polymer has a good balance of hardness and elastic properties, and it is possible to form an outermost surface layer that is tough and excellent in both scratch resistance and wear resistance. Furthermore, a relatively large oxidation potential of the molecule from structures of X _1, have the difficult to oxidize characteristics, is relatively stable even when the oxidizing gas such as ozone or NOx gas exposure, gas resistance It is possible to provide an electrophotographic photosensitive member that is strong against damage.
However, in the general formula (2), X ₁ is an alkylene group having 1 to 4 carbon atoms, an alkylidene group having 2 to 6 carbon atoms, and two alkylidene groups having 2 to 6 carbon atoms bonded via a phenylene group. Represents a divalent group or an oxygen atom, and Ar ₄ , Ar ₅ , Ar ₆ , Ar ₇ , Ar ₈ and Ar ₉ are divalent aromatics having 6 to 18 carbon atoms which may have an alkyl group as a substituent. Represents a group hydrocarbon group.

In the general formula (2), examples of the alkylene group having 1 to 4 carbon atoms for X _1, for example, methylene group, ethylene group, propylene group, etc. linear or branched alkylene group such as butylene group .
In the general formula (2), examples of the alkylidene group having 2 to 6 carbon atoms in X ₁ include 1,1-ethylidene group, 1,1-propylidene group, 2,2-propylidene group, 1,1- A butylidene group, a 2,2-butylidene group, 3,3-pentanylidene, 3,3-hexanylidene and the like can be mentioned.
In the general formula (3), examples of the divalent group in which two alkylidene groups having 2 to 6 carbon atoms are bonded via the phenylene group in X ₁ include those having the following structures.
In the structural formula, Me represents a methyl group.

There is no restriction | limiting in particular as a compound represented by the said General formula (2), Although it can select suitably according to the objective, It is represented by the following general formula (2-1) at the point which is excellent in a crosslinking reaction. Compounds are preferred.
In the general formula (2-1), _{X 2 is, -CH 2 -, - CH 2} CH 2 -, - C (CH 3) 2 -Ph-C (CH 3) 2 -, - C (CH ₂ ) Represents _5- or -O-, and R ₄ , R ₅ , R ₆ , R ₇ , R ₈ and R ₉ may be the same or different, and may be a hydrogen atom or a methyl group Or an ethyl group, Ph represents a phenylene group, and o, p, q, r, s, and t represent an integer of 1 to 4.

  The compound represented by the general formula (2-1) is particularly excellent among the compounds represented by the general formula (2), and the mutual polymerization reactivity is particularly good. Further, it has the same characteristics as the general formula (2), has a good balance between hardness characteristics and elastic characteristics, is strong in gas resistance, and can form a crosslinked charge transport layer having a high crosslinking density. .

There is no restriction | limiting in particular as a compound represented by the said General formula (2), According to the objective, it can select suitably, For example, following structural formula (2-1)-(2-31) is mentioned, for example. The compound etc. which are represented by these are mentioned. In addition, the compounds represented by the following structural formulas (2-1) to (2-24) are also specific examples of the compounds represented by the general formula (2-1).
However, in the structural formulas, Me represents a methyl group, and Et represents an ethyl group.

--- Compound represented by formula (3) ---
The compound represented by the following general formula (3) has four [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound, and some [(( Tetrahydro-2H-pyran-2-yl) oxy] methyl group is likely to form a three-dimensional cross-linked polymer. In addition, it has a diamine structure via a specific aromatic hydrocarbon structure represented by Y ₁ , enables intramolecular charge transfer, and enables formation of a crosslinked protective layer having high hole mobility. Therefore, it is possible to provide an electrophotographic photosensitive member having a low bright portion potential even when the time from optical writing to developing on the photosensitive member is shortened as in high-speed printing or printing with a small diameter drum.
In the general formula (3), _{Y 1} represents a benzene, biphenyl, terphenyl, stilbene, distyryl benzene, or a divalent group of condensed polycyclic aromatic _{hydrocarbons,} Ar _{10, Ar} 11, Ar ₁₂ and Ar ₁₃ represent a C 6-18 divalent aromatic hydrocarbon group which may have an alkyl group as a substituent.

In the general formula (3), examples of the condensed polycyclic aromatic hydrocarbon in Y ₁ include naphthalene, phenanthrene, anthracene, and pyrene.
Examples of the alkyl group that is a substituent of the divalent aromatic hydrocarbon group having 6 to 18 carbon atoms of Ar ₁₀ , Ar ₁₁ , Ar _12, and Ar ₁₃ include a methyl group and an ethyl group.

There is no restriction | limiting in particular as a compound represented by the said General formula (3), Although it can select suitably according to the objective, It is represented by the following general formula (3-1) at the point which is excellent in a crosslinking reaction. Compounds are preferred.
In the general formula (3-1), _{Y 2} represents a benzene, biphenyl, terphenyl, stilbene, or a divalent group of naphthalene. R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ may be the same or different and each represents a hydrogen atom, a methyl group or an ethyl group, and u, v, w and z are 1 to 1 Represents an integer of 4.

  The compound represented by the general formula (3-1) is particularly excellent among the compounds represented by the general formula (3), and the mutual polymerization reactivity is particularly good. Further, it has the same characteristics as the general formula (3), and it is possible to form a crosslinked protective layer having good potential characteristics and high crosslinking density.

There is no restriction | limiting in particular as a compound represented by the said General formula (3), According to the objective, it can select suitably, For example, following structural formula (3-1)-(3-27) is mentioned, for example. The compound etc. which are represented by these are mentioned. The compounds represented by the following structural formulas (3-1) to (3-3), (3-10) to (3-12), and (3-15) to (3-22) It is also a specific example of the compound represented by (3-1).
However, in the structural formulas, Me represents a methyl group, and Et represents an ethyl group.

--Method for synthesizing a compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound--
The compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound is a novel compound, and for example, by the following first to second synthesis methods Can be synthesized.

--- First synthesis method ---
Specifically, as the first synthesis method, (1) an aldehyde form of a charge transporting compound is synthesized, and (2) the resulting aldehyde form of the charge transporting compound is reacted with a reducing agent to form a methylol compound. (Methylol body of charge transporting compound) was synthesized, and (3) the obtained methylol compound and 3,4-dihydro-2H-pyran were reacted to produce the above-mentioned [(tetrahydro-2H-pyran-2-yl) And a method of synthesizing a compound having three or more oxy] methyl groups.

The method for synthesizing the aldehyde form of the charge transporting compound (1) is not particularly limited and may be appropriately selected depending on the purpose. For example, as shown in the following reaction formula, the charge transporting compound is used as a raw material. And a method of synthesizing this by formylation using a conventionally known method (for example, Vilsmeier reaction). Details are described in the formylation described in Japanese Patent No. 3934522, and those methods can be used.
The method for formylating three or more aromatic rings of the charge transporting compound is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a method using zinc chloride, phosphorus oxychloride, dimethylformaldehyde or the like Etc.
However, in reaction formula, n represents the integer of 0-2 and m represents the integer of 3-n. Ar represents any aromatic ring of the charge transporting compound used in the present invention.

There is no restriction | limiting in particular as a synthesis method of said (2) methylol compound (methylol body of a charge transport compound), According to the objective, it can select suitably, For example, an aldehyde compound (charge | charge shown by following Reaction Formula) Examples thereof include a method of synthesizing a methylol compound by using a transporting compound (aldehyde form) as an intermediate and using a conventionally known reduction method.
There is no restriction | limiting in particular as a reduction method at the time of synthesize | combining the methylol body of the said charge transport compound, Although it can select suitably according to the objective, the reduction method using a sodium borohydride is preferable.
However, in reaction formula, n represents the integer of 0-2 and m represents the integer of 3-n. Ar represents any aromatic ring of the charge transporting compound used in the present invention.

The method for synthesizing the compound having three or more (3) [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups is not particularly limited and can be appropriately selected according to the purpose. A methylol compound as shown in the following reaction formula is used as an intermediate, and 3,4-dihydro-2H-pyran is subjected to an addition reaction in the presence of an acid catalyst to produce [(tetrahydro-2H-pyran-2-yl) oxy] methyl. And a method of synthesizing a compound having three or more groups.
However, in reaction formula, n represents the integer of 0-2 and m represents the integer of 3-n. Ar represents any aromatic ring of the charge transporting compound used in the present invention.

--- Second synthesis method ---
As the second synthesis method, specifically, (1) an intermediate compound having [(tetrahydro-2H-pyran-2-yl) oxy] methyl group is synthesized, and (2) an amine compound is synthesized using the intermediate compound. Examples thereof include a method of synthesizing a charge transporting compound by a coupling reaction with a compound.

Examples of the synthesis method of the intermediate compound having the (1) [(tetrahydro-2H-pyran-2-yl) oxy] methyl group include a compound having a halogen and a methylol group in an aromatic ring as a raw material, and the methylol group Is synthesized with 3,4-dihydro-2H-pyran in the presence of an acid catalyst to synthesize an intermediate compound having a halogen and a [(tetrahydro-2H-pyran-2-yl) oxy] methyl group.
However, in the formula, X represents a halogen.

(2) As a method for synthesizing a compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound, the above-mentioned [(tetrahydro-2H-pyran-2 -Il) oxy] A method of synthesizing a charge transporting compound by coupling an intermediate compound having a methyl group with an amine compound. Depending on the series and number of amines in the amine compound, a large number of [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups can be introduced at one time. In addition, when the halogen is an iodo form, it can be coupled by an Ullmann reaction, and when the halogen is a chloro form or a bromo form, it can be coupled by a Suzuki-Miyaura reaction using a palladium catalyst.
However, Ar represents an arbitrary aromatic ring of the charge transporting compound used in the present invention.

--- Polymerization method ---
Next, the polymerization reaction will be described.
Compounds having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound are heated by adding vinyl sulfonic acid as a curing catalyst. Each of [[tetrahydro-2H-pyran-2-yl) oxy] methyl group is cut and eliminated to bond and polymerize to form a three-dimensional network macromolecule (the three-dimensional crosslinked polymer). Form. At this time, some [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups remain unreacted. Although the reaction in which a part of this [(tetrahydro-2H-pyran-2-yl) oxy] methyl group is cut and eliminated has not been clarified, it is not a single reaction but a plurality of reactions as shown below. Is a reaction in which the compounds are linked to each other and are linked together.

--- Reaction mode ---
The reaction mode is shown below.
A compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound is combined with the following reaction modes 1 to 3 to form complex bonds While taking the form, it is presumed to polymerize into a three-dimensional network to form a macromolecule.
All of these reactions are reactions in which a part of the (tetrahydro-2H-pyran-2-yl) oxy group is cut off and eliminated, and accompanied by a decrease in weight. Therefore, weight loss is observed when these compositions are heated with an acid catalyst by a TG-DTA thermal analyzer.
Further, when the gas components generated during the heating reaction are analyzed by mass spectrometry gas chromatography (GC-MS), (tetrahydro-2H-pyran-2-yl such as 3,4-dihydro-2H-pyran, 5-hydroxypentanal, etc.) ) A desorption product indicating that a part of the oxy group is broken is detected.

[Reaction mode 1]
In Reaction Mode 1, the tetrahydro-2H-pyran-2-yl group portion of one [(tetrahydro-2H-pyran-2-yl) oxy] methyl group is cut off and eliminated, and the other [(tetrahydro-2H- Pyran-2-yl) oxy] is a reaction that forms a dimethylene ether bond while the (tetrahydro-2H-pyran-2-yl) oxy group portion of the methyl group is cut off and eliminated.
However, Ar represents an arbitrary aromatic ring of the charge transporting compound used in the present invention.

[Reaction mode 2]
Reaction mode 2 forms an ethylene bond while the (tetrahydro-2H-pyran-2-yl) oxy groups of both [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups are cut off and eliminated. It is a reaction.
However, Ar represents an arbitrary aromatic ring of the charge transporting compound used in the present invention.

[Reaction mode 3]
Reaction mode 3 consists in that the (tetrahydro-2H-pyran-2-yl) oxy group of one [(tetrahydro-2H-pyran-2-yl) oxy] methyl group is cut off and eliminated while the other aromatic ring is removed. To form a methylene bond.
However, Ar represents an arbitrary aromatic ring of the charge transporting compound used in the present invention.

  In general, the (tetrahydro-2H-pyran-2-yl) oxy group is known as a hydroxyl-protecting group, but in the three-dimensional crosslinked polymer of the present invention, [(tetrahydro-2H-pyran-2-yl ) Oxy] methyl group remains, and no deprotection reaction occurs. That is, it is considered that the [(tetrahydro-2H-pyran-2-yl) oxy] methyl group is not hydrolyzed and changed to a methylol group.

  Furthermore, the (tetrahydro-2H-pyran-2-yl) oxy group has a low polarity, and the (tetrahydro-2H-pyran-2-yl) oxy group remaining as unreacted has an adverse effect on electrical properties and image quality. Does not reach.

  In addition, the polymerization reaction tends to form a highly strained film, but the relatively large [(tetrahydro-2H-pyran-2-yl) oxy] methyl group has an effect of reducing strain, An effect of filling a molecular space caused by strain can be expected, and a toughest outermost layer with low gas permeability and reduced brittleness can be formed.

  The reaction ratio and residual ratio of [(tetrahydro-2H-pyran-2-yl) oxy] methyl group in the molecule can be arbitrarily changed in order to adjust the structure of the charge transporting compound and the target film properties. However, if the residual amount is too small, the film is fragile and has a large strain, which is not suitable for a long-life electrophotographic photosensitive member. Further, in order to increase the reaction rate, it is necessary to increase the temperature, and there is a problem of photosensitive deterioration due to the influence of heat, which may cause adverse effects such as a decrease in sensitivity and an increase in residual potential. Further, if the amount of the residue is excessive, the crosslink density is lowered, and in some cases, the crosslinkage is poor so as to be dissolved in an organic solvent, and the tough mechanical properties derived from the three-dimensional crosslinkable polymer are not exhibited. Therefore, it is preferable to select a curing condition that satisfies both mechanical and electrostatic characteristics.

-Method for forming three-dimensional crosslinked polymer-
The formation of the three-dimensional crosslinked polymer may be performed simultaneously with the formation of the outermost surface layer.
There is no restriction | limiting in particular as a formation method of the said three-dimensional crosslinked polymer, According to the objective, it can select suitably, For example, [(tetrahydro-2H-pyran-2-yl) is added to the aromatic ring of the said charge transport compound. Oxy] A compound having at least three methyl groups and a vinyl sulfonic acid as a curing catalyst, and further, if necessary, a coating solution containing other components is diluted with a solvent or the like as necessary. Examples of the method include adjusting and coating the surface of the electrophotographic photosensitive member, followed by drying by heating and polymerization. At this time, the outermost surface layer can be obtained by forming a three-dimensional crosslinked polymer in a film shape.

  There is no restriction | limiting in particular as heating temperature at the time of forming the said three-dimensional crosslinked polymer, Although it can select suitably according to the objective, 80 to 160 degreeC is preferable, 100 to 150 degreeC is more preferable, 135 C. to 150.degree. C. is particularly preferable. When the heating temperature is less than 80 ° C., the reaction rate becomes slow and it may not be possible to reach a sufficient crosslinking density over a long period of time. When the heating temperature exceeds 160 ° C., the reaction speeds up, but the crosslinking density increases too much, causing a decrease in charge transportability, increasing the bright part potential of the electrophotographic photosensitive member, lowering the sensitivity, and reducing the electrophotographic sensitivity. The influence of heating on other layer constituting materials of the body is increased, and the electrophotographic photoreceptor may be deteriorated.

  There is no restriction | limiting in particular as the quantity of the said vinyl sulfonic acid at the time of forming the said three-dimensional crosslinked polymer, Although it can select suitably according to the objective, [(tetrahydro- 2H-pyran-2-yl) oxy] with respect to 100 parts by mass of the compound having 3 or more methyl groups, 0.01 part by mass to 1.0 part by mass is preferable, and 0.05 part by mass to 0.5 part by mass. Is more preferable, and 0.1 to 0.2 parts by mass is particularly preferable. If the amount is less than 0.01 parts by mass, mechanical durability (abrasion resistance) may be inferior due to insufficient crosslinking reaction, and if it exceeds 1.0 parts by mass, the image is poor in a high-temperature and high-humidity environment. May occur. When the amount is within the particularly preferable range, it is advantageous in terms of both mechanical durability (wear resistance) and image quality.

-Other ingredients-
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, a solvent, a leveling agent, antioxidant, a filler, etc. are mentioned.

--Solvent--
The solvent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include alcohol solvents such as methanol, ethanol, propanol and butanol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone. Ester solvents such as ethyl acetate and butyl acetate; ether solvents such as tetrahydrofuran, methyltetrahydrofuran, dioxane, propyl ether, diethylene glycol dimethyl ether and propylene glycol 1-monomethyl ether-2-acetate; dichloromethane, dichloroethane, trichloroethane, chlorobenzene, etc. Halogen solvents; aromatic solvents such as benzene, toluene, xylene; celloso such as methyl cellosolve, ethyl cellosolve, cellosolve acetate Such as blanking-based solvents, and the like. These may be used alone or in combination of two or more.

  The dilution ratio of the solvent is not particularly limited and is appropriately selected depending on the solubility of the composition, the coating method such as the dip coating method, the spray coating method, the bead coating method, the ring coating method, the target thickness, and the like. be able to.

--Leveling agent--
The leveling agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include silicone oils such as dimethyl silicone oil and methyl phenyl silicone oil; polymers or oligomers having a perfluoroalkyl group in the side chain. Etc.
There is no restriction | limiting in particular as content of the said leveling agent, Although it can select suitably according to the objective, 1 mass% or less is preferable with respect to the total solid of the said coating liquid.

--Antioxidant--
The antioxidant can be added for the purpose of preventing a decrease in sensitivity of the electrophotographic photosensitive member against repeated use, an increase in residual potential, and the like.
The antioxidant may be added to each layer such as the cross-linked charge transport layer, the charge transport layer, the charge generation layer, and the other layers.

  There is no restriction | limiting in particular as said antioxidant, According to the objective, it can select suitably, For example, phenolic compounds, paraphenylenediamines, hydroquinones, organic sulfur compounds, organic phosphorus compounds, etc. are mentioned. It is done. These may be used individually by 1 type and may use 2 or more types together.

  The phenolic compounds are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di -T-butyl-4-ethylphenol, stearyl-β- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2'-methylene-bis- (4-methyl-6-t- Butylphenol), 2,2'-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4'-thiobis- (3-methyl-6-tert-butylphenol), 4,4'-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2 4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate ] Methane, bis [3,3′-bis (4′-hydroxy-3′-t-butylphenyl) butyric acid] glycol ester, tocopherols and the like.

  The paraphenylenediamines are not particularly limited and may be appropriately selected depending on the intended purpose. For example, N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-di-sec-butyl -P-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'-di-isopropyl-p-phenylenediamine, N, N'-dimethyl-N, N'-di-t -Butyl-p-phenylenediamine and the like.

  There is no restriction | limiting in particular as said hydroquinones, According to the objective, it can select suitably, For example, 2, 5- di- t-octyl hydroquinone, 2, 6- didodecyl hydroquinone, 2-dodecyl hydroquinone, 2- Examples include dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, and 2- (2-octadecenyl) -5-methylhydroquinone.

  The organic sulfur compounds are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include dilauryl-3,3′-thiodipropionate and distearyl-3,3′-thiodipropionate. And ditetradecyl-3,3′-thiodipropionate.

  The organic phosphorus compounds are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, And tri (2,4-dibutylphenoxy) phosphine.

There is no restriction | limiting in particular as said antioxidant, You may use what was synthesize | combined suitably, and may use a well-known commercial item as antioxidants, such as rubber | gum, a plastics, and fats and oils.
There is no restriction | limiting in particular as content of the said antioxidant, Although it can select suitably according to the objective, It is 0. 0 with respect to the total mass of the layer (outermost surface layer) formed with the said coating liquid. 01 mass%-10 mass% are preferable, and 0.01 mass%-1 mass% are more preferable.

--Filler--
The filler can be added for the purpose of improving the further wear resistance of the coating solution.
There is no restriction | limiting in particular as said filler, According to the objective, it can select suitably, For example, an organic filler material, an inorganic filler material, etc. are mentioned.

There is no restriction | limiting in particular as said organic filler material, According to the objective, it can select suitably, For example, fluororesin powders, such as polytetrafluoroethylene, silicone resin powder, a-carbon powder, etc. are mentioned.
There is no restriction | limiting in particular as said inorganic filler material, According to the objective, it can select suitably, For example, metal powder, such as copper, tin, aluminum, an indium; Silica, a tin oxide, a zinc oxide, a titanium oxide, an alumina Zirconium oxide, indium oxide, antimony oxide, bismuth oxide, calcium oxide, antimony-doped tin oxide, tin-doped indium oxide and other metal oxides; tin fluoride, calcium fluoride, aluminum fluoride and other metal oxides Examples thereof include potassium titanate and boron nitride.
Among these, inorganic materials are preferable from the viewpoint of excellent wear resistance, and α-type alumina having a hexagonal close-packed structure is more preferable from the viewpoint of excellent insulation, thermal stability, and wear resistance.

  There is no restriction | limiting in particular as an average primary particle diameter of the said filler, Although it can select suitably according to the objective, 0.01 micrometer-0.5 micrometer are preferable at the point which is excellent in a light transmittance, abrasion resistance, etc. If the average primary particle size is less than 0.01 μm, it may cause a decrease in abrasion resistance, a decrease in dispersibility, and the like. If it exceeds 0.5 μm, the settling property of the filler is promoted, and the toner Filming may occur.

  There is no restriction | limiting in particular as content of the said filler, Although it can select suitably according to the objective, It is 5 mass%-with respect to the total mass of the layer (outermost surface layer) formed with the said coating liquid. 50 mass% is preferable and 10 mass%-40 mass% are more preferable. When the content is less than 5% by mass, the wear resistance may be insufficient, and when it exceeds 50% by mass, the transparency may be impaired.

  Furthermore, these fillers can be surface-treated with at least one kind of surface treatment agent, which is preferable because the dispersibility of the filler is improved. Decreasing the dispersibility of the filler not only increases the residual potential, but also decreases the transparency of the coating, causes defects in the coating, and decreases the wear resistance. It can develop into a big problem.

--- Surface treatment agent ---
The surface treatment agent is not particularly limited and may be appropriately selected depending on the intended purpose. However, a surface treatment agent capable of maintaining the insulating properties of the filler is preferable, and in terms of filler dispersibility and image blur, a titanate system is preferable. Coupling agent, aluminum coupling agent, zircoaluminate coupling agent, higher fatty acid or a mixture of these with silane coupling agent; Al ₂ O ₃ , TiO ₂ , ZrO ₂ , silicone, aluminum stearate or these A mixture is more preferred. The treatment with the silane coupling agent is strongly influenced by image blur, but the influence may be suppressed by performing a mixing treatment of the surface treatment agent and the silane coupling agent.

  There is no restriction | limiting in particular as the quantity of the said surface treating agent, Although it changes with the average primary particle diameters of the filler to be used, and it can select suitably according to the objective, 3 mass%-30 mass% are with respect to the said filler. Preferably, 5% by mass to 20% by mass is more preferable. When the content is less than 3% by mass, the filler dispersion effect may not be obtained. When the content exceeds 30% by mass, the residual potential may be significantly increased.

-Coating-
There is no restriction | limiting in particular as said coating, According to the objective, it can select suitably, For example, a dip coating method, a spray coat method, a bead coat method, a ring coat method etc. are mentioned.

The charge transportability of the three-dimensional cross-linked polymer has the highest level of characteristics as compared with a conventional cross-linked film, but is still lower than that of a normal molecular dispersion type charge transport layer. Therefore, it is preferable to use a conventional molecular dispersion type charge transport layer as the charge transport layer and use a three-dimensional cross-linked polymer as a protective layer (outermost surface layer) on the surface.
That is, it is possible to provide an electrophotographic photosensitive member having the above characteristics without deteriorating sensitivity characteristics by forming a thin cross-linked charge transport layer on a relatively thick normal molecular dispersion type charge transport layer. become.

  There is no restriction | limiting in particular as thickness of the said outermost surface layer (the said bridge | crosslinking type charge transport layer), Although it can select suitably according to the objective, 1 micrometer-10 micrometers are preferable, and 3 micrometers-8 micrometers are more preferable. If the thickness is less than 1 μm, it may not be possible to achieve a sufficiently long life. If the thickness exceeds 10 μm, the sensitivity may decrease, the bright part potential may increase, and stable image output may be difficult. .

<< Charge generation layer >>
The charge generation layer contains a charge generation material, preferably contains a binder resin, and further contains other components such as the above-mentioned antioxidant as necessary.

-Charge generation material-
There is no restriction | limiting in particular as said charge generation substance, According to the objective, it can select suitably, For example, an inorganic material, an organic material, etc. are mentioned.

--Inorganic materials--
There is no restriction | limiting in particular as an inorganic material, According to the objective, it can select suitably, For example, crystalline selenium, amorphous-selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compound, amorphous silicon ( For example, a dangling bond terminated with a hydrogen atom, a halogen atom or the like; a boron atom, a phosphorus atom or the like doped is preferred.

--- Organic materials--
The organic material is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine; azulenium salt pigments, squaric acid methine pigments, and carbazole skeletons. Azo pigments having a triphenylamine skeleton, azo pigments having a diphenylamine skeleton, azo pigments having a dibenzothiophene skeleton, azo pigments having a fluorenone skeleton, azo pigments having an oxadiazole skeleton, azo having a bisstilbene skeleton Pigment, azo pigment having distyryl oxadiazole skeleton, azo pigment having distyryl carbazole skeleton, perylene pigment, anthraquinone or polycyclic quinone pigment, quinoneimine pigment, diphenylmethane and triphenylmethane face , Benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, indigoid pigments, and bis-benzimidazole-based pigments. These may be used individually by 1 type and may use 2 or more types together.

-Binder resin-
The binder resin is not particularly limited and can be appropriately selected according to the purpose. For example, polyamide resin, polyurethane resin, epoxy resin, polyketone resin, polycarbonate resin, silicone resin, acrylic resin, polyvinyl butyral resin, Examples thereof include polyvinyl formal resin, polyvinyl ketone resin, polystyrene resin, poly-N-vinyl carbazole resin, polyacrylamide resin and the like. These may be used individually by 1 type and may use 2 or more types together.

  In addition to the above-mentioned binder resin, the binder resin may include a charge transporting polymer material having a charge transport function. For example, (1) an arylamine skeleton, a benzidine skeleton, a hydrazone skeleton, a carbazole skeleton, Polymer materials having a stilbene skeleton, a pyrazoline skeleton, etc., such as polycarbonate, polyester, polyurethane, polyether, polysiloxane, and acrylic resin, and (2) a polymer material having a polysilane skeleton can be used.

  Specific examples of the above (1) include, for example, JP-A-01-001728, JP-A-01-009964, JP-A-01-013061, JP-A-01-019049, JP-A-01-241559. JP, 04-011627, JP 04-175337, JP 04-183719, JP 04-22514, JP 04-230767, JP 04-320420, JP 05-232727, JP 05-310904, JP 06-234836, JP 06-234837, JP 06-234838, JP 06-234839, JP JP 06-234840, JP 06-234841 A, JP 06-23904 JP, JP-A 06-236050, JP-A 06-236051, JP-A 06-295077, JP-A 07-056374, JP 08-176293, JP 08-208820. JP-A-08-21640, JP-A-08-253568, JP-A-08-269183, JP-A-09-062019, JP-A-09-038883, JP-A-09-71642, Special Japanese Laid-Open Patent Application Nos. 09-87376, 09-104746, 09-110974, 09-110976, 09-157378, 09-221544, 09 JP-A No. 227669, JP-A No. 09-235367, JP-A No. 09-2413 No. 9, JP 09-268226 A, JP 09-272735 A, JP 09-302084 A, JP 09-302085 A, JP 09-328539 A, etc. Examples include polymer materials.

  Specific examples of the above (2) include polysilylene weights described in, for example, JP-A 63-285552, JP-A 05-19497, JP-A 05-70595, JP-A 10-73944, and the like. Examples thereof include charge transporting polymer materials such as coalescence.

-Other ingredients-
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, a low molecular charge transport material, a solvent, a leveling agent etc. are mentioned, You may include the above-mentioned antioxidant.

--Low molecular charge transport material--
There is no restriction | limiting in particular as said low molecular charge transport material, According to the objective, it can select suitably, For example, an electron transport material, a hole transport material, etc. are mentioned.

  The electron transport material is not particularly limited and may be appropriately selected depending on the intended purpose. For example, chloroanil, bromilyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone 2,4,5,7-tetranitro-9-fluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1 , 2-b] thiophen-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, diphenoquinone derivatives and the like. These may be used individually by 1 type and may use 2 or more types together.

  The hole transport material is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, and triarylamine derivatives. , Stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc. Derivatives, enamine derivatives and the like. These may be used individually by 1 type and may use 2 or more types together.

--Solvent--
The solvent is not particularly limited and may be appropriately selected depending on the intended purpose.For example, tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclopentanone, anisole, xylene, methyl ethyl ketone, Acetone, ethyl acetate, butyl acetate and the like can be mentioned. These may be used individually by 1 type and may use 2 or more types together.

--Leveling agent--
There is no restriction | limiting in particular as said leveling agent, According to the objective, it can select suitably, For example, silicone oils, such as dimethyl silicone oil and methylphenyl silicone oil, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.

-Method for forming charge generation layer-
The method for forming the charge generation layer is not particularly limited and may be appropriately selected depending on the purpose. For example, the charge generation material and the binder resin are dissolved or dispersed in the other components such as the solvent. For example, a method of forming the coating liquid obtained by applying the coating liquid on the conductive support and drying it may be used. In addition, the said coating liquid can be apply | coated by the casting method etc., for example.

  There is no restriction | limiting in particular as thickness of the said charge generation layer, Although it can select suitably according to the objective, 0.01 micrometer-5 micrometers are preferable, and 0.05 micrometer-2 micrometers are more preferable.

<< Charge transport layer >>
The charge transport layer is a layer intended to hold a charged charge and to couple the charge generated and separated in the charge generation layer by exposure to the charged charge held by movement. In order to achieve the purpose of holding the charged charge, it is required that the electric resistance is high. Further, in order to achieve the purpose of obtaining a high surface potential with the charged charge that has been held, it is required that the dielectric constant is small and the charge mobility is good.

  The charge transport layer contains a charge transport material, preferably contains a binder resin, and further contains other components as necessary.

-Charge transport material-
The charge transport material is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include an electron transport material, a hole transport material, and a polymer charge transport material.

--Electron transport material--
The electron transport material (electron-accepting material) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2, 4, 7 -Trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro -4H-indeno [1,2-b] thiophene-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, and the like. These may be used alone or in combination of two or more.

--- Hole transport material--
The hole transport material (electron donating material) is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (P-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, Examples include acridine derivatives, benzofuran derivatives, benzimidazole derivatives, thiophene derivatives, and the like. These may be used alone or in combination of two or more.

--- Polymer charge transport material--
The polymer charge transport material is not particularly limited and may be appropriately selected depending on the intended purpose.For example, a polymer having a carbazole ring, a polymer having a hydrazone structure, a polysilylene polymer, or a triarylamine structure may be used. For example, a polymer having an electron donating group, and other polymers.

  The polymer having a carbazole ring is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include poly-N-vinylcarbazole, JP-A-50-82056, and JP-A-54-9632. And the compounds described in JP-A Nos. 54-11737, 4-175337, 4-183719, and 6-234841.

  The polymer having the hydrazone structure is not particularly limited and may be appropriately selected depending on the intended purpose. For example, JP-A-57-78402, JP-A-61-20953, JP-A-61. JP-A-296358, JP-A-1-134456, JP-A-1-179164, JP-A-3-180851, JP-A-3-180852, JP-A-3-50555, JP-A-5-310904. And the compounds described in JP-A-6-234840.

  The polysilylene polymer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include JP-A 63-285552, JP-A 1-88461, and JP-A 4-264130. Examples thereof include compounds described in JP-A-4-264131, JP-A-4-264132, JP-A-4-264133, and JP-A-4-289867.

  The polymer having a triarylamine structure is not particularly limited and may be appropriately selected depending on the intended purpose. For example, N, N-bis (4-methylphenyl) -4-aminopolystyrene, JP-A-134457, JP-A-2-282264, JP-A-2-304456, JP-A-4-133305, JP-A-4-1330666, JP-A-5-40350, JP-A-5-202135. And the compounds described in the Japanese Patent Publication.

  The polymer having an electron-donating group is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include copolymers with known monomers, block polymers, graft polymers, and stars. Examples thereof include polymers. Furthermore, for example, a crosslinked polymer having an electron donating group as disclosed in JP-A-3-109406 can also be used.

  Examples of the other polymer include, for example, formaldehyde condensation polymer of nitropyrene, JP-A-51-73888, JP-A-56-150749, JP-A-6-234836, JP-A-6-234837. And the like.

  In addition to the above, the polymer charge transporting material includes, for example, a polycarbonate resin having a triarylamine structure, a polyurethane resin having a triarylamine structure, a polyester resin having a triarylamine structure, and a polyarylamine structure having a polyarylamine structure. Examples include ether resins. Examples of the polymer charge transporting material include JP-A 64-1728, JP-A 64-13061, JP-A 64-19049, JP-A-4-11627, JP-A 4-116627. JP 2225014, JP 4-230767, JP 4-320420, JP 5-232727, JP 7-56374, JP 9-127713, JP 9-222740. And compounds described in JP-A-9-265197, JP-A-9-211877, JP-A-9-30495, and the like.

-Binder resin-
The binder resin is not particularly limited and can be appropriately selected depending on the purpose. For example, polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyethylene resin, polyvinyl chloride resin, polyvinyl acetate resin, Examples include polystyrene resin, phenol resin, epoxy resin, polyurethane resin, polyvinylidene chloride resin, alkyd resin, silicone resin, polyvinyl carbazole resin, polyvinyl butyral resin, polyvinyl formal resin, polyacrylate resin, polyacrylamide resin, and phenoxy resin. These may be used alone or in combination of two or more.
The charge transport layer may also contain a copolymer of a crosslinkable binder resin and a crosslinkable charge transport material.

-Other ingredients-
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, a solvent, a plasticizer, a leveling agent, etc. are mentioned, The above-mentioned antioxidant may be included.

--Solvent--
The solvent is not particularly limited and may be appropriately selected depending on the purpose. The same solvent as the charge generation layer can be used, but a solvent that dissolves the charge transport material and the binder resin satisfactorily. preferable. These may be used singly or in combination of two or more.

--Plasticizer--
The plasticizer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate.
There is no restriction | limiting in particular as content of the said plasticizer, Although it can select suitably according to the objective, 0 mass part-30 mass parts are preferable with respect to 100 mass parts of said binder resins.

--Leveling agent--
The leveling agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include silicone oils such as dimethyl silicone oil and methyl phenyl silicone oil; polymers or oligomers having a perfluoroalkyl group in the side chain. Etc.
There is no restriction | limiting in particular as content of the said leveling agent, Although it can select suitably according to the objective, 0 mass part-1 mass part are preferable with respect to 100 mass parts of said binder resins.

-Method for forming charge transport layer-
The method for forming the charge transport layer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the charge transport material and the binder resin are dissolved or dispersed in the other components such as the solvent. And a method of forming the coating liquid obtained by coating on the charge generation layer and drying. In addition, the said coating liquid can be apply | coated by the casting method etc., for example.

  There is no restriction | limiting in particular as thickness of the said charge transport layer, Although it can select suitably according to the objective, 5 micrometers-40 micrometers are preferable, and 10 micrometers-30 micrometers are more preferable.

<< Other layers >>
There is no restriction | limiting in particular as said other layer, According to the objective, it can select suitably, For example, an undercoat layer, an intermediate | middle layer, etc. are mentioned.

-Undercoat layer-
The undercoat layer can be provided between the conductive support and the photosensitive layer.
The undercoat layer contains a resin and, if necessary, further contains other components such as the above-mentioned antioxidant, fine powder pigment, and coupling agent.

The resin contained in the undercoat layer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include water-soluble resins such as polyvinyl alcohol, casein and sodium polyacrylate, copolymer nylon, and methoxymethyl. Examples thereof include alcohol-soluble resins such as nylon fluoride, curable resins that form a three-dimensional network structure, such as polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy resin.
Among these, a resin having high solvent resistance with respect to a general organic solvent is preferable in that the photosensitive layer is coated on the resin with a solvent.

  The fine powder pigment contained in the undercoat layer is not particularly limited as long as it is a pigment that can prevent moire, reduce residual potential, etc., and can be appropriately selected according to the purpose. Examples thereof include metal oxides such as titanium, silica, alumina, zirconium oxide, tin oxide, and indium oxide.

  There is no restriction | limiting in particular as a coupling agent contained in the said undercoat layer, According to the objective, it can select suitably, For example, a silane coupling agent, a titanium coupling agent, a chromium coupling agent etc. are mentioned.

  There is no restriction | limiting in particular as said undercoat layer, According to the objective, it can select suitably, For example, a single layer may be sufficient and the lamination | stacking of two or more layers may be sufficient as the combination of the said kind.

The method for forming the undercoat layer is not particularly limited and may be appropriately selected depending on the purpose, for example, forming method using the appropriate solvent and coating method as described above in the photosensitive layer; Al ₂ O ₃ And a method of forming an organic material such as polyparaxylylene (parylene) and an inorganic material such as SiO ₂ , SnO ₂ , TiO ₂ , ITO, and CeO ₂ by a vacuum thin film manufacturing method. .

  There is no restriction | limiting in particular as thickness of the said undercoat layer, Although it can select suitably according to the objective, 1 micrometer-5 micrometers are preferable.

-Intermediate layer-
The intermediate layer is intended to suppress mixing of charge transport layer components into the cross-linked charge transport layer or improve adhesion between both layers between the charge transport layer and the cross-linked charge transport layer. Can be provided.

  The intermediate layer is suitably insoluble or sparingly soluble in the crosslinkable charge transport layer coating solution, contains a binder resin, and further contains other components such as the above-mentioned antioxidant as necessary. contains.

  The binder resin contained in the intermediate layer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. .

  There is no restriction | limiting in particular as a formation method of the said intermediate | middle layer, According to the objective, it can select suitably, For example, the method of forming using a suitable solvent and a coating method like the above-mentioned photosensitive layer etc. are mentioned.

  There is no restriction | limiting in particular as thickness of the said intermediate | middle layer, Although it can select suitably according to the objective, 0.05 micrometer-2 micrometers are preferable.

  Hereinafter, embodiments of the electrophotographic photosensitive member of the present invention will be described.

<First Embodiment>
The layer structure of the electrophotographic photoreceptor according to the first embodiment will be described with reference to FIG.
FIG. 1 shows a configuration example of the most basic laminated photoconductor, in which a charge generation layer 2 and a charge transport layer 3 are sequentially laminated on a conductive support 1. When used in a negative charge, a hole transporting charge transport material is used for the charge transport layer, and when used in a positive charge, an electron transporting charge transport material is used for the charge transport layer. In this case, the outermost surface layer is the charge transport layer 3.

<Second Embodiment>
The layer structure of the electrophotographic photosensitive member according to the second embodiment will be described with reference to FIG.
FIG. 2 is a configuration in which the undercoat layer 4 is provided on the laminated photoconductor of the basic configuration (first embodiment), and is the most practical configuration. In this case, the outermost surface layer is the charge transport layer 3.

<Third Embodiment>
The layer structure of the electrophotographic photosensitive member according to the third embodiment will be described with reference to FIG.
FIG. 3 shows a configuration in which a cross-linked charge transport layer 5 is further provided on the outermost surface as a protective layer in the second embodiment. In this case, the outermost surface layer is the crosslinkable charge transport layer 5.
Here, the undercoat layer 4 is not essential, but it plays an important function for prevention of charge leakage and the like, and is usually used.
In the case of this photoconductor structure, the charge transfer from the charge generation layer to the surface of the photoconductor is shared by the two layers of the charge transport layer 3 and the cross-linked charge transport layer 5, and the main functions can be separated. For example, by combining a charge transport layer having excellent charge transportability with a cross-linked charge transport layer having excellent mechanical durability, it is possible to provide an electrophotographic photoreceptor having excellent charge transportability and excellent mechanical durability. .

<Fourth Embodiment>
The layer configuration of the electrophotographic photosensitive member according to the fourth embodiment will be described with reference to FIG.
FIG. 4 shows a configuration in which a photosensitive layer 6 mainly composed of a charge generation material and a charge transport material is provided on a conductive support 1. In this case, the outermost surface layer is the photosensitive layer 6.
It is necessary to contain the charge generating substance in the outermost surface layer, and a coating liquid for forming the outermost surface layer is prepared by mixing and dispersing the charge generating substance. The outermost surface layer is prepared by a polymerization reaction by drying.

<Fifth Embodiment>
The layer structure of the electrophotographic photosensitive member according to the fifth embodiment will be described with reference to FIG.
FIG. 5 shows a configuration in which a protective layer 7 is provided on a single photosensitive layer 6. In this case, the outermost surface layer is the protective layer 7.

<Method for producing electrophotographic photoreceptor>
The method for producing the electrophotographic photoreceptor of the present invention is not particularly limited and may be appropriately selected depending on the intended purpose. The electrophotographic photoreceptor has at least a photosensitive layer on the conductive support and the conductive support. The method for producing the electrophotographic photosensitive member of the present invention having an outermost surface layer having a three-dimensional crosslinked polymer on the outermost surface, wherein vinylsulfonic acid is used as a curing catalyst, and the aromatic ring of the charge transporting compound is [( [Tetrahydro-2H-pyran-2-yl) oxy] by a reaction in which a part of the [(tetrahydro-2H-pyran-2-yl) oxy] methyl group is removed from the compound having three or more groups. A method for producing an electrophotographic photoreceptor including a three-dimensional crosslinked polymer forming step of polymerizing to form the three-dimensional crosslinked polymer is preferable.

There is no restriction | limiting in particular as said electroconductive support body, According to the objective, it can select suitably, For example, the said electroconductive support body etc. which were illustrated in description of the said electrophotographic photoreceptor are mentioned.
There is no restriction | limiting in particular as a formation method of the said electroconductive support body, According to the objective, it can select suitably.
The photosensitive layer is not particularly limited as long as it has the outermost surface layer on the outermost surface, and can be appropriately selected according to the purpose. For example, at least a charge generation layer, a charge transport layer, an outermost surface layer ( And a photosensitive layer having other layers as necessary.
The charge generation layer and the charge transport layer are not particularly limited and may be appropriately selected depending on the purpose. For example, the charge generation layer and the charge transport layer exemplified in the description of the electrophotographic photoreceptor Is mentioned.
There is no restriction | limiting in particular as a formation method of the said charge generation layer and the said charge transport layer, According to the objective, it can select suitably.

  There is no restriction | limiting in particular as said 3D crosslinked polymer formation process, According to the objective, it can select suitably, For example, the formation method of the said 3D crosslinked polymer illustrated in description of the said electrophotographic photoreceptor of this invention etc. Is mentioned.

(Image forming apparatus and image forming method)
The image forming apparatus of the present invention includes at least an electrophotographic photosensitive member, a charging unit, an exposure unit, a developing unit, and a transfer unit, and further includes other units as necessary. The electrophotographic photosensitive member used in the image forming apparatus is the above-described electrophotographic photosensitive member of the present invention. The charging unit and the exposure unit may be collectively referred to as an electrostatic latent image forming unit.
The image forming method according to the present invention includes at least a charging step, an exposure step, a development step, and a transfer step, and further includes other steps as necessary. The electrophotographic photosensitive member used in the image forming method is the above-described electrophotographic photosensitive member of the present invention. The charging process and the exposure process may be collectively referred to as an electrostatic latent image forming process.
The image forming method can be suitably performed by the image forming apparatus. The charging step can be preferably performed by the charging unit, the exposure step can be preferably performed by the exposure unit, the development step can be preferably performed by the developing unit, and the transfer step is performed by the transfer unit. The other steps can be preferably performed by the other means.

<Charging step and charging means>
The charging step is not particularly limited as long as it is a step for charging the surface of the electrophotographic photosensitive member, and can be appropriately selected according to the purpose. For example, the charging unit can be implemented.
The charging means is not particularly limited as long as it is a means for charging the surface of the electrophotographic photosensitive member, and can be appropriately selected according to the purpose. For example, a conductive or semiconductive roll, brush, film , A contact charger known per se with a rubber blade, a non-contact charger using corona discharge such as corotron and scorotron (proximity system having a gap of 100 μm or less between the surface of the electrophotographic photosensitive member and the charger) Non-contact charger).

<Exposure process and exposure means>
The exposure step is not particularly limited as long as it is a step of exposing the charged electrophotographic photosensitive member surface to form an electrostatic latent image, and can be appropriately selected according to the purpose. It can be implemented by means.
The exposure means is not particularly limited as long as it is a means for exposing a charged electrophotographic photosensitive member surface to form an electrostatic latent image, and can be appropriately selected according to the purpose. System, rod lens array system, laser optical system, liquid crystal shutter optical system, LED optical system, and other various exposure devices. Examples of the light source in the exposure device include a light source capable of securing high luminance such as a light emitting diode (LED), a semiconductor laser (LD), and electroluminescence (EL). In the present invention, an optical backside system that performs imagewise exposure from the backside of the electrophotographic photosensitive member may be employed.
The electrostatic latent image writing on the electrophotographic photosensitive member in the exposure step is preferably performed by a digital method. Thus, it is possible to provide an image forming method capable of efficiently dealing with a document and image production output on a PC (personal computer).
The electrostatic latent image writing on the electrophotographic photosensitive member by the exposure unit is preferably a digital method. As a result, an image forming apparatus capable of efficiently dealing with documents and image production output on a PC can be provided.

<Development process and development means>
The development step is not particularly limited as long as it is a step of developing the electrostatic latent image with toner to form a visible image, and can be appropriately selected according to the purpose. It can be implemented by means.
The developing unit is not particularly limited as long as it is a unit that develops the electrostatic latent image with toner to form a visible image, and can be appropriately selected according to the purpose. It is preferable to have at least a developing unit that stores the developer to be applied and can apply the developer to the electrostatic latent image in a contact or non-contact manner. The developing unit may be a dry developing type, a wet developing type, a single color developing unit, or a multicolor developing unit. Also good. Among these, those having a stirrer for charging the developer by frictional stirring and a rotatable magnet roller are preferable. In the developing device, for example, the toner and the carrier are mixed and agitated, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. . Since the magnet roller is disposed in the vicinity of the electrophotographic photosensitive member, a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is electrically attracted to the electrophotographic photosensitive member. Move to the surface of the body. As a result, the electrostatic latent image is developed with the toner, and a visible image is formed with the toner on the surface of the electrophotographic photosensitive member.

<Transfer process and transfer means>
The transfer step is not particularly limited as long as it is a step of transferring the visible image to a recording medium, and can be appropriately selected according to the purpose.
The transfer means is not particularly limited as long as it is a means for transferring the visible image to a recording medium, and can be appropriately selected according to the purpose.
As the transfer step, for example, a method of directly transferring a visible image from the surface of the electrophotographic photosensitive member to a recording medium, an intermediate transfer member, a primary image is transferred onto the intermediate transfer member, There is a method in which a visible image is secondarily transferred onto the recording medium. Either aspect can be used satisfactorily, but the former (direct transfer) method with a small number of transfers is preferred when the adverse effect of the transfer is great when the image quality is improved. The transfer can be performed, for example, by charging the electrophotographic photosensitive member with the transfer charger using the visible image, and can be performed by the transfer unit.

<Fixing process and fixing means>
The fixing step is not particularly limited as long as it is a step of fixing the transferred image transferred to the recording medium, and can be appropriately selected according to the purpose. For example, it can be performed by the fixing unit.
The fixing unit is not particularly limited as long as it is a unit that fixes the transferred image transferred onto the recording medium, and can be appropriately selected according to the purpose. However, a known heating and pressing unit is preferable. Examples of the heating and pressing means include a combination of a heating roller and a pressure roller, and a combination of a heating roller, a pressure roller, and an endless belt. The heating in the heating and pressurizing means is usually preferably 80 ° C to 200 ° C. The fixing may be performed, for example, every time the toner of each color is transferred to the recording medium, or may be performed simultaneously in a state where the toner of each color is stacked.

<Other processes and other means>
The other steps and other means are not particularly limited and may be appropriately selected depending on the purpose. For example, the charge removal step and the charge removal unit, the cleaning step and the cleaning unit, the recycling step and the recycling unit, the control step, and the like. A control means etc. are mentioned.

-Static elimination process and static elimination means-
The neutralization step is not particularly limited as long as it is a step of performing neutralization by applying a neutralization bias to the electrophotographic photosensitive member, and can be appropriately selected according to the purpose. it can.
The neutralization unit is not particularly limited as long as it is a unit that performs neutralization by applying a neutralization bias to the electrophotographic photosensitive member, and can be appropriately selected according to the purpose. Examples thereof include a neutralization lamp. It is done.

-Cleaning process and cleaning means-
The cleaning step is not particularly limited as long as it is a step for removing the toner remaining on the electrophotographic photosensitive member, and can be appropriately selected according to the purpose. For example, the cleaning step can be performed by the cleaning unit.
The cleaning unit is not particularly limited as long as it is a unit that removes the toner remaining on the electrophotographic photosensitive member, and can be appropriately selected according to the purpose. For example, a magnetic brush cleaner or an electrostatic brush Examples include cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, web cleaners, and the like.

-Recycling process and recycling means-
The recycling step is not particularly limited as long as it is a step of recycling the toner removed in the cleaning step to the developing unit, and can be appropriately selected according to the purpose. For example, the recycling unit can be implemented by the recycling unit. .
There is no restriction | limiting in particular as said recycling means, According to the objective, it can select suitably, For example, a well-known conveyance means etc. are mentioned.

-Control process and control means-
The control step is not particularly limited as long as it is a step for controlling each step, and can be appropriately selected according to the purpose. For example, the control step can be performed by the control means.
The control means is not particularly limited as long as it is a means for controlling each step, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

  The image forming apparatus and the image forming method have high image stability during repeated use, can maintain high image quality with few image defects over a long period of time, and are excellent in environmental stability and gas resistance stability.

  Hereinafter, embodiments of the image forming apparatus of the present invention will be described.

  FIG. 6 is a schematic view showing an example of the electrophotographic process and the image forming apparatus of the present invention, and the following examples also belong to the category of the present invention.

  As shown in FIG. 6, the electrophotographic photosensitive member 10 rotates in the direction of the arrow, and around the electrophotographic photosensitive member 10, a charging member 11 as a charging unit, an image exposure member 12 as an exposure unit, and a developing unit. A developing member 13 as a transfer member, a transfer member 16 as a transfer unit, a cleaning member 17 as a cleaning unit, a charge removal member 18 as a charge removal unit, and the like are disposed. The cleaning member 17 and the charge removal member 18 may be omitted.

  As shown in FIG. 6, the operation of the image forming apparatus is basically as follows. The charging member 11 charges the surface of the electrophotographic photoreceptor 10 almost uniformly. Subsequently, image light writing corresponding to the input signal is performed by the image exposure member 12 to form an electrostatic latent image. Next, the electrostatic latent image is developed by the developing member 13, and a toner image is formed on the surface of the electrophotographic photosensitive member. The formed toner image is transferred by a transfer member 16 onto a transfer paper 15 as a recording medium sent to a transfer site by a conveying roller 14. This toner image is fixed on the transfer paper 15 by a fixing device (not shown). A part of the toner that has not been transferred to the transfer paper is cleaned by the cleaning member 17. Subsequently, the charge remaining on the electrophotographic photosensitive member is neutralized by the neutralizing member 18, and the process proceeds to the next cycle.

  As shown in FIG. 6, the electrophotographic photosensitive member 10 has a drum shape, but may have a sheet shape or an endless belt shape. For the charging member 11 and the transfer member 16, in addition to corotron, scorotron, solid state charger (solid state charger), roller-shaped charging members or brush-shaped charging members are used, and all known means can be used. It is.

  On the other hand, light sources such as the image exposure member 12 and the charge removal member 18 emit light such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL). All things can be used. Among these, a semiconductor laser (LD) and a light emitting diode (LED) are mainly used. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.

  By providing a transfer process, a static elimination process, a cleaning process, or a pre-exposure process using light irradiation, the electrophotographic photosensitive member 10 is irradiated with light. However, the exposure of the electrophotographic photosensitive member 10 in the charge removal step has a large influence of fatigue on the electrophotographic photosensitive member 10, and may cause a decrease in charging or an increase in residual potential. Therefore, there are cases where it is possible to eliminate static electricity by applying a reverse bias in the charging process or cleaning process instead of static elimination by exposure, which may be effective from the viewpoint of enhancing the durability of the electrophotographic photosensitive member.

  When the electrophotographic photosensitive member 10 is positively (negatively) charged and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the electrophotographic photosensitive member. A positive image can be obtained by developing this with negative (positive) toner (electrodetection fine particles), and a negative image can be obtained by developing with positive (negative) toner. A known method is applied to the developing unit, and a known method is also used for the charge eliminating unit.

  Among the contaminants that adhere to the surface of the electrophotographic photosensitive member, discharge substances generated by charging and external additives contained in the toner are easy to pick up the effects of humidity and cause abnormal images. Paper dust is one of the causative substances of images, and when they adhere to the electrophotographic photosensitive member, not only abnormal images are likely to occur, but also wear resistance is reduced or uneven wear is reduced. There is a tendency to cause. Therefore, it is more preferable from the viewpoint of high image quality that the electrophotographic photosensitive member and the paper are not in direct contact for the above reasons.

  The toner developed on the electrophotographic photosensitive member 10 by the developing member 13 is transferred to the transfer paper 15, but not all is transferred, and toner remaining on the electrophotographic photosensitive member 10 is also generated. Such toner is removed from the electrophotographic photosensitive member 10 by the cleaning member 17. As the cleaning member 17, a known member such as a cleaning blade or a cleaning brush is used. Moreover, both may be used together.

  The electrophotographic photosensitive member according to the present invention can be applied to a small-diameter electrophotographic photosensitive member because it realizes high photosensitivity and high stability. Accordingly, as an image forming apparatus or a method thereof in which the above electrophotographic photosensitive member is used more effectively, each developing unit corresponding to a plurality of color toners has a plurality of corresponding electrophotographic photosensitive members, Accordingly, the image forming apparatus is extremely effectively used for a so-called tandem image forming apparatus that performs parallel processing. The tandem image forming apparatus includes at least four color toners of yellow (C), magenta (M), cyan (C), and black (K) required for full-color printing and a developing unit that holds them. In addition, by providing at least four electrophotographic photosensitive members corresponding to them, full-color printing can be performed at a very high speed as compared with a conventional image forming apparatus capable of full-color printing.

  FIG. 7 is a schematic view showing an example of the tandem-type full-color electrophotographic apparatus of the present invention, and the following modifications also belong to the category of the present invention.

  In FIG. 7, electrophotographic photoreceptors (10C (cyan), 10M (magenta), 10Y (yellow), 10K (black)) are drum-shaped electrophotographic photoreceptors 10, and these photoreceptors (10C, 10M). , 10Y, 10K) rotate in the direction of the arrow in the figure, and at least in that order around the charging member (11C, 11M, 11Y, 11K), the developing member (13C, 13M, 13Y, 13K), the cleaning member (17C) , 17M, 17Y, 17K). Laser light (12C) from an image exposure member (not shown) from the outside of the electrophotographic photosensitive member 10 between the charging member (11C, 11M, 11Y, 11K) and the developing member (13C, 13M, 13Y, 13K). , 12M, 12Y, 12K), and electrostatic latent images are formed on the electrophotographic photosensitive members (10C, 10M, 10Y, 10K).

  In FIG. 7, four image forming elements (20C, 20M, 20Y, 20K) centering on the electrophotographic photosensitive member (10C, 10M, 10Y, 10K) are along the transfer conveyance belt 19 which is a transfer material conveyance means. Are juxtaposed. The transfer conveyance belt 19 is electrophotographic between the developing member (13C, 13M, 13Y, 13K) of each image forming unit (20C, 20M, 20Y, 20K) and the cleaning member (17C, 17M, 17Y, 17K). Transfer members (16C, 16M) for applying a transfer bias to the surface (rear surface) which is in contact with the photoconductors (10C, 10M, 10Y, 10K) and contacts the back side of the transfer conveyance belt 19 on the electrophotographic photoconductor 10 side. , 16Y, 16K). Each of the image forming elements (20C, 20M, 20Y, 20K) is different in toner color inside the developing device, and the other components have the same configuration.

  In the color electrophotographic apparatus having the configuration shown in FIG. 7, the image forming operation is performed as follows. First, in each image forming element (20C, 20M, 20Y, 20K), the charging member (11C, 11M) in which the electrophotographic photosensitive member (10C, 10M, 10Y, 10K) rotates along with the electrophotographic photosensitive member 10 is rotated. , 11Y, 11K), and then, an image of each color to be created is formed by laser light (12C, 12M, 12Y, 12K) by an exposure unit (not shown) arranged outside the electrophotographic photosensitive member 10. A corresponding electrostatic latent image is formed.

  Next, the latent image is developed by a developing member (13C, 13M, 13Y, 13K) to form a toner image. The developing members (13C, 13M, 13Y, 13K) are developing members that perform development with toners of C (cyan), M (magenta), Y (yellow), and K (black), respectively. 10C, 10M, 10Y, and 10K) are overlaid on the transfer belt 19).

  The transfer paper 15 is sent out from the tray by a paper feed roller 21, temporarily stopped by a pair of registration rollers 22, and sent to the transfer member 23 in synchronism with the image formation on the electrophotographic photosensitive member. The toner image held on the transfer belt 19 is transferred onto the transfer paper 15 by an electric field formed from the potential difference between the transfer bias applied to the transfer member 23 and the transfer belt 19. The toner image transferred onto the transfer paper is conveyed, the toner is fixed onto the transfer paper by the fixing member 24, and is discharged to a paper discharge unit (not shown). Further, residual toner remaining on each electrophotographic photosensitive member (10C, 10M, 10Y, 10K) without being transferred at the transfer portion is removed by a cleaning member (17C, 17M, 17Y, 17K) provided in each unit. Collected.

The intermediate transfer system as shown in FIG. 7 is particularly effective for an image forming apparatus capable of full color printing. A plurality of toner images are once formed on an intermediate transfer body and then transferred onto paper at a time, thereby causing color misregistration. This is easy to control and is effective for high image quality.
The intermediate transfer member includes various materials or shapes such as a drum shape and a belt shape. In the present invention, any conventionally known intermediate transfer member can be used. Effective and useful for high durability and high image quality.

  In the example of FIG. 7, the image forming elements are arranged in the order of Y (yellow), M (magenta), C (cyan), and K (black) from the upstream side to the downstream side in the transfer sheet conveyance direction. However, it is not limited to this order, and the color order is arbitrarily set. Further, when a black-only document is created, it is particularly effective to use the present invention to provide a mechanism that stops the image forming elements (20C, 20M, 20Y) other than black.

  The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge.

(Process cartridge)
The process cartridge according to the present invention includes an electrophotographic photosensitive member and at least one unit selected from a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a slow charging unit, and is detachable from the image forming apparatus. In a certain process cartridge, the electrophotographic photosensitive member is the above-described electrophotographic photosensitive member of the present invention. As a result, it is possible to provide a process cartridge that has high image stability during repeated use and can maintain high image quality with few image defects over a long period of time, and is excellent in environmental stability and gas resistance.

  As shown in FIG. 8, the process cartridge includes an electrophotographic photosensitive member 10, and in addition, a charging member 11, an image exposure member 12, a developing member 13, a transfer member 16, a cleaning member 17, and a charge eliminating member. One device (component) including Reference numeral 15 denotes a transfer paper.

EXAMPLES Next, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not restrict | limited to the following Example.
In addition, all "parts" used in an Example represent a mass part.
Further, the abbreviation, p-TolSO ₃ H represents paratoluenesulfonic acid, EtOH represents ethanol, t-Bu ₃ P represents tritertiary butylphosphine, and t-BuONa represents tertiary butoxy sodium. Pd (OAc) ₂ represents palladium acetate, and Pd [(t-Bu) ₃ P] ₂ represents bis (tri-t-butoxyphosphine) palladium.

(Synthesis Example 1)
<Synthesis of intermediate material of three-dimensional crosslinked polymer>
Synthesis of 4-[(tetrahydro-2H-pyran-2-yl) oxy] methyl bromobenzene, which is an intermediate of the material of the three-dimensional crosslinked polymer, was performed by the following procedure.
First, 4-bromobenzyl alcohol (50.43 g), 3,4-dihydro-2H-pyran (45.35 g), and tetrahydrofuran (150 mL) were placed in a four-necked flask and stirred at 5 ° C., paratoluene. Sulfonic acid (0.512 g) was dropped to prepare a solution. Subsequently, this solution was stirred at room temperature for 2 hours, extracted with ethyl acetate, dehydrated with magnesium sulfate, and subjected to adsorption treatment with activated clay and silica gel. And the target object was obtained by filtering, wash | cleaning, and concentrating this (yield 72.50g, colorless oily substance). The reaction formula is shown below. FIG. 9 shows an infrared absorption spectrum (KBr tablet method) of the compound obtained in Synthesis Example 1.

(Synthesis Example 2)
<Synthesis of methylol compound (Comparative Example Compound A)>
Synthesis of 4,4′-bis [di (4-hydroxymethylphenyl) amino] diphenylmethane, which is a methylol intermediate, was performed according to the following procedure.
First, an intermediate aldehyde compound (12.30 g) and ethanol (150 mL) were placed in a four-necked flask, stirred at room temperature, and sodium borohydride (3.63 g) was dropped to prepare a solution. Subsequently, this solution was stirred at room temperature for 4 hours, extracted with ethyl acetate, dehydrated with magnesium sulfate, and adsorbed with activated clay and silica gel. Then, this was filtered, washed, and concentrated to obtain an amorphous substance. This was dispersed in n-hexane, filtered, washed, and dried to obtain the desired product (yield 12.0 g, pale yellowish white amorphous product). The reaction formula is shown below. FIG. 10 shows an infrared absorption spectrum (KBr tablet method) of the compound obtained in Synthesis Example 2.

(Synthesis Example 3)
<Synthesis of Intermediate Methylol Compound (Comparative Example Compound B)>
First, an intermediate aldehyde compound (3.29 g) and ethanol (50 mL) were placed in a four-necked flask, stirred at room temperature, and sodium borohydride (1.82 g) was dropped to prepare a solution. Next, this solution was stirred at room temperature for 12 hours, extracted with ethyl acetate, dehydrated with magnesium sulfate, and subjected to adsorption treatment with activated clay and silica gel. And this was filtered, wash | cleaned, and concentrated, and the crystal substance was obtained. This was dispersed in n-hexane, filtered, washed, and dried to obtain the desired product (yield 2.78 g, white crystals). The reaction formula is shown below. FIG. 11 shows an infrared absorption spectrum (KBr tablet method) of the compound obtained in Synthesis Example 3.

(Synthesis Example 4)
<Synthesis of three-dimensional crosslinked polymer material>
A compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of a charge transporting compound which is a material of a three-dimensional crosslinked polymer (represented by the following structural formula (1-4)) The compound was synthesized according to the following procedure.
First, an intermediate methylol compound (3.4 g), 3,4-dihydro-2H-pyran (4.65 g), and tetrahydrofuran (100 mL) were placed in a four-necked flask and stirred at 5 ° C., paratoluene sulfone. A solution was prepared by dropping acid (58 mg). Subsequently, this solution was stirred at room temperature for 5 hours, extracted with ethyl acetate, dehydrated with magnesium sulfate, and subjected to adsorption treatment with activated clay and silica gel. And this was filtered, washed, and concentrated to obtain a yellow oily substance. This yellow oily substance was purified and purified by a silica gel column (toluene / ethyl acetate = 10/1) (volume ratio) to obtain the desired product (yield 2.7 g, colorless oily substance). The reaction formula is shown below. FIG. 12 shows an infrared absorption spectrum (KBr tablet method) of the compound obtained in Synthesis Example 4.

(Synthesis Example 5)
<Synthesis of three-dimensional crosslinked polymer material>
A compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of a charge transporting compound that is a material of a three-dimensional crosslinked polymer (represented by the following structural formula (2-1)) The compound was synthesized according to the following procedure.
First, 4,4′-diaminodiphenylmethane (2.99 g), the compound obtained in Synthesis Example 1 (17.896 g), palladium acetate (0.336 g), tertiary butoxy sodium (13.83 g), and o- Xylene (100 mL) was placed in a four-necked flask, stirred at room temperature under an argon gas atmosphere, and tritertial butylphosphine (1.214 g) was added dropwise to prepare a solution. Subsequently, this solution was stirred at 80 ° C. for 1 hour, stirred at reflux for 1 hour, diluted with toluene, dehydrated with magnesium sulfate, and subjected to adsorption treatment with activated clay and silica gel. And this was filtered, washed, and concentrated to obtain a yellow oily substance. This yellow oily substance was purified and isolated on a silica gel column (toluene / ethyl acetate = 20/1) (volume ratio) to obtain the desired product (yield 5.7 g, light yellow amorphous substance). The reaction formula is shown below. FIG. 13 shows an infrared absorption spectrum (KBr tablet method) of the compound obtained in Synthesis Example 5.

(Synthesis Example 6)
<Synthesis of three-dimensional crosslinked polymer material>
A compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of a charge transporting compound that is a material of a three-dimensional crosslinked polymer (represented by the following structural formula (2-8)) The compound was synthesized according to the following procedure.
First, 4,4′-diaminodiphenyl ether (3.0 g), the compound obtained in Synthesis Example 1 (17.896 g), palladium acetate (0.336 g), tertiary butoxy sodium (13.83 g), and o- Xylene (100 mL) was placed in a four-necked flask, stirred at room temperature under an argon gas atmosphere, and tritertial butylphosphine (1.214 g) was added dropwise to prepare a solution. Next, this solution was stirred at 80 ° C. for 1 hour, stirred at reflux for 1 hour, diluted with toluene, dehydrated with magnesium sulfate, and subjected to adsorption treatment with activated clay and silica gel. And this was filtered, washed, and concentrated to obtain a yellow oily substance. This yellow oily substance was purified and purified by a silica gel column (toluene / ethyl acetate = 10/1) (volume ratio) to obtain the desired product (yield 5.7 g, pale yellow oily substance). The reaction formula is shown below. FIG. 14 shows an infrared absorption spectrum (KBr tablet method) of the compound obtained in Synthesis Example 6.

(Synthesis Example 7)
<Synthesis of three-dimensional crosslinked polymer material>
A compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of a charge transporting compound that is a material of a three-dimensional crosslinked polymer (represented by the following structural formula (2-13)) The compound was synthesized according to the following procedure.
First, 4,4′-ethylenedianiline (3.18 g), the compound obtained in Synthesis Example 1 (17.896 g), palladium acetate (0.336 g), sodium tertiary butoxy (13.83 g), and o -Xylene (100 mL) was put into a four-necked flask, stirred at room temperature under an argon gas atmosphere, and tritertiary butylphosphine (1.214 g) was added dropwise to prepare a solution. Subsequently, this solution was stirred at 80 ° C. for 1 hour, stirred at reflux for 1 hour, diluted with toluene, dehydrated with magnesium sulfate, and subjected to adsorption treatment with activated clay and silica gel. And this was filtered, washed, and concentrated to obtain a yellow oily substance. This yellow oily substance was purified and purified by a silica gel column (toluene / ethyl acetate = 20/1) (volume ratio) to obtain the desired product (yield 5.7 g, pale yellow oily substance). The reaction formula is shown below. FIG. 15 shows an infrared absorption spectrum (KBr tablet method) of the compound obtained in Synthesis Example 7.

(Synthesis Example 8)
<Synthesis of three-dimensional crosslinked polymer material>
A compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of a charge transporting compound that is a material of a three-dimensionally crosslinked polymer (represented by the following structural formula (2-21)) The compound was synthesized according to the following procedure.
First, α, α′-bis (4-aminophenyl) -1,4-diisopropylbenzene (10.335 g), the compound obtained in Synthesis Example 1 (39.05 g), palladium acetate (0.673 g), Tasha Rubutoxy sodium (27.677 g) and o-xylene (200 mL) were put into a four-necked flask, stirred at room temperature under an argon gas atmosphere, and tritertiary butylphosphine (2.43 g) was added dropwise. A solution was prepared. Next, this solution was stirred at 80 ° C. for 1 hour, stirred at reflux for 2 hours, diluted with toluene, dehydrated with magnesium sulfate, and subjected to adsorption treatment with activated clay and silica gel. And this was filtered, washed, and concentrated to obtain a yellow oily substance. The yellow oily substance was purified and purified on a silica gel column (toluene / ethyl acetate = 10/1) (volume ratio) to obtain the desired product (yield 23.5 g, pale yellow amorphous substance). The reaction formula is shown below. FIG. 16 shows an infrared absorption spectrum (KBr tablet method) of the compound obtained in Synthesis Example 8.

(Synthesis Example 9)
<Synthesis of three-dimensional crosslinked polymer material>
A compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of a charge transporting compound that is a material of a three-dimensional crosslinked polymer (represented by the following structural formula (2-18) The compound was synthesized according to the following procedure.
First, 1,1-bis (4-aminophenyl) cyclohexene (9.323 g), the compound obtained in Synthesis Example 1 (45.55 g), palladium acetate (0.785 g), tarbutoxy sodium (32.289 g) ) And o-xylene (300 mL) were placed in a four-necked flask, stirred at room temperature under an argon gas atmosphere, and tritertiary butylphosphine (2.43 g) was added dropwise to prepare a solution. Next, this solution was stirred at 80 ° C. for 1 hour, stirred at reflux for 2 hours, diluted with toluene, dehydrated with magnesium sulfate, and subjected to adsorption treatment with activated clay and silica gel. And this was filtered, washed, and concentrated to obtain a yellow oily substance. This yellow oily substance was isolated by purification on a silica gel column (toluene / ethyl acetate = 10/1) (volume ratio) to obtain the desired product (yield 11.42 g, yellow amorphous substance). The reaction formula is shown below. FIG. 17 shows an infrared absorption spectrum (KBr tablet method) of the compound obtained in Synthesis Example 9.

(Synthesis Example 10)
<Synthesis of three-dimensional crosslinked polymer material>
A compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of a charge transporting compound that is a material of a three-dimensional crosslinked polymer (represented by the following structural formula (3-3)) The compound was synthesized according to the following procedure.
First, 1,3-phenylenediamine (0.541 g), the compound obtained in Synthesis Example 1 (6.508 g), tert-butoxy sodium (3.844 g), bis (tri-t-butoxyphosphine) palladium (52 mg) ) And o-xylene (20 mL) were placed in a four-necked flask and stirred at room temperature under an argon gas atmosphere to prepare a solution. Next, this solution was diluted with toluene, dehydrated with magnesium sulfate, and adsorbed with activated clay and silica gel. And this was filtered, washed, and concentrated to obtain a yellow oily substance. The yellow oily substance was purified and purified with a silica gel column (toluene / ethyl acetate = 10/1) (volume ratio) to obtain the desired product (yield 3.02 g, pale yellow amorphous substance). The reaction formula is shown below. FIG. 18 shows an infrared absorption spectrum (KBr tablet method) of the compound obtained in Synthesis Example 10.

(Synthesis Example 11)
<Synthesis of three-dimensional crosslinked polymer material>
A compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of a charge transporting compound that is a material of a three-dimensional crosslinked polymer (represented by the following structural formula (3-22) The compound was synthesized according to the following procedure.
First, 1,5-diaminonaphthalene (0.791 g), the compound obtained in Synthesis Example 1 (6.508 g), tert-butoxy sodium (3.844 g), bis (tri-t-butoxyphosphine) palladium (52 mg) ) And o-xylene (20 mL) were placed in a four-necked flask and stirred at room temperature under an argon gas atmosphere to prepare a solution. Subsequently, this solution was stirred at reflux for 1 hour, diluted with toluene, dehydrated with magnesium sulfate, and subjected to adsorption treatment with activated clay and silica gel. And this was filtered, washed, and concentrated to obtain a yellow oily substance. This yellow oily substance was purified and isolated on a silica gel column (toluene / ethyl acetate = 9/1) (volume ratio) to obtain the desired product (yield 2.56 g, pale yellow amorphous substance). The reaction formula is shown below. FIG. 19 shows an infrared absorption spectrum (KBr tablet method) of the compound obtained in Synthesis Example 11.

Example 1
<Manufacture of electrophotographic photoreceptor>
On an aluminum cylinder having a diameter of 30 mm, an undercoat layer coating solution having the following composition, a charge generation layer coating solution having the following composition, and a charge transporting layer coating solution having the following composition are sequentially applied and dried. A 3.5 μm subbing layer, a 0.2 μm thick charge generation layer, and a 25 μm thick charge transport layer were formed.
On the obtained charge transport layer, a cross-linked charge transport layer coating solution having the following composition is spray-coated, heat-dried at 150 ° C. for 30 minutes, and a cross-linked charge transport layer (outermost surface layer) having a thickness of 5.0 μm. ). Thus, the electrophotographic photosensitive member of Example 1 was manufactured.

[Composition of undercoat layer coating solution]
・ Alkyd resin: 6 parts (Beccosol 1307-60-EL, manufactured by DIC Corporation)
Melamine resin: 4 parts (Super Becamine G-821-60, manufactured by DIC Corporation)
・ Titanium oxide (CREL, manufactured by Ishihara Sangyo Co., Ltd.) ・ ・ ・ 40 parts ・ Methyl ethyl ketone ・ ・ ・ 50 parts

[Composition of charge generation layer coating solution]
・ Polyvinyl butyral (XYHL, manufactured by UCC) ・ ・ ・ 0.5 part ・ Cyclohexanone ・ ・ ・ 200 parts ・ Methyl ethyl ketone ・ ・ ・ 80 parts ・ Bisazo pigment represented by the following structural formula: 2.4 parts

[Composition of charge transport layer coating solution]
-Bisphenol Z polycarbonate (Panlite TS-2050, manufactured by Teijin Chemicals Ltd.) ... 10 parts-Tetrahydrofuran ... 100 parts-Tetrahydrofuran solution of 1 mass% silicone oil (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.2 part Low molecular charge transport material represented by the following structural formula (A-1) 5 parts

[Composition of crosslinking type charge transport layer (outermost surface layer) coating solution]
Compound represented by structural formula (1-4) synthesized in Synthesis Example 4 (material of three-dimensional cross-linked polymer) ... 10 parts Vinyl sulfonic acid (manufactured by Asahi Kasei Finechem Co., Ltd.) ... 0.015 part Tetrahydrofuran (special grade) ... 90 parts

(Examples 2 to 10)
<Manufacture of electrophotographic photoreceptor>
The same procedure as in Example 1 was performed except that [3-dimensional crosslinked polymer material] in [Crosslinked charge transport layer coating solution] in Example 1 was replaced with [3-dimensional crosslinked polymer material] shown in Table 1. Thus, an electrophotographic photosensitive member was produced.

(Comparative Example 1)
<Manufacture of electrophotographic photoreceptor>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that vinyl sulfonic acid in [Crosslinking type charge transport layer coating solution] in Example 1 was replaced with dodecylbenzene sulfonic acid.

(Comparative Example 2)
<Manufacture of electrophotographic photoreceptor>
In Example 1, electrophotography was carried out in the same manner as in Example 1 except that 0.015 part of vinyl sulfonic acid in [Crosslinking type charge transport layer coating solution] was replaced with 0.045 part of dodecylbenzene sulfonic acid. A photoconductor was prepared.

(Comparative Example 3)
In Example 1, except that [Material of three-dimensional crosslinked polymer] in [Crosslinked charge transport layer coating solution] was changed to Comparative Example Compound A represented by the following structural formula, An electrophotographic photosensitive member was produced.

(Comparative Example 4)
In Example 1, except that [Material of three-dimensional crosslinked polymer] in [Crosslinked charge transport layer coating solution] was changed to Comparative Example Compound B represented by the following structural formula, An electrophotographic photosensitive member was produced.

(Comparative Example 5)
<Manufacture of electrophotographic photoreceptor>
In Example 9, an electrophotographic photosensitive member was produced in the same manner as in Example 9 except that the vinyl sulfonic acid in [Crosslinking type charge transport layer coating solution] was replaced with para-toluene sulfonic acid.

(Comparative Example 6)
<Manufacture of electrophotographic photoreceptor>
In Example 1, electrophotography was performed in the same manner as in Example 1 except that 0.015 part of vinyl sulfonic acid in [Crosslinkable charge transport layer coating solution] was replaced with 0.0255 part of paratoluene sulfonic acid. A photoconductor was prepared.

<Solubility test and surface smoothness evaluation of cross-linked charge transport layer (outermost surface layer)>
The crosslinking reactivity of the crosslinked charge transport layer was evaluated by a solubility test. The solubility test was performed by the following method. A cross-linked charge transport layer coating solution was applied directly onto an aluminum support in the same manner as in Examples 1 to 10 and Comparative Examples 1 to 6, and heat-dried with a cotton swab dipped in tetrahydrofuran. The surface of the film (cured product) was rubbed and the surface was observed. The evaluation results are shown in Table 1. The solubility was evaluated as “dissolved” when the surface was dissolved or peeled off, and “undissolved” when the surface was intact or traced.
The surface smoothness was evaluated by determining the ten-point average roughness (Rz) value according to JIS-1982 standard of the surface of the cross-linked charge transport layer with a surface roughness shape measuring instrument (Surfcom 1400D, manufactured by Tokyo Seimitsu Co., Ltd.). . The case where 1 μm or less was “good” and the case where it exceeded 1 μm was judged as “bad”.

  The cured films of Examples 1 to 10 and Comparative Examples 1 to 6 had good crosslinking reactivity, and all became insoluble in solubility. The surface smoothness was also good.

<Image output evaluation>
The mechanical durability, electrical characteristics, environmental stability, and gas resistance stability of each electrophotographic photosensitive member produced in Examples 1 to 10 and Comparative Examples 1 to 6 were evaluated. The obtained electrophotographic photosensitive member was mounted on a process cartridge of a digital full color multi-functional peripheral “imageioNeo455” manufactured by Ricoh Co., Ltd., and after setting the dark portion potential to 700 (−V), a total of 100,000 sheets were printed. The results are shown in Table 2.
The image quality was evaluated by outputting a 600 dpi 2 × 2 image chart and measuring with an image densitometer (X-Rite 939: manufactured by SDG).
Mechanical durability was evaluated by measuring the wear amount from the difference in thickness of the cross-linked charge transport layer at the initial stage and after printing 100,000 sheets.
Electrical characteristics were evaluated by image exposure light source light amount of the initial and 100,000 sheets after printing is measured and dark potential of the light portion potential and 100,000 sheets after printing at about 0.4μJ / cm ^2.
Environmental stability was evaluated based on the image quality of the output image when the image output device was placed in a high-temperature and high-humidity chamber at 30 ° C. and 90% RH after printing 100,000 sheets.
Gas resistance stability was measured using a NOx exposure test apparatus (manufactured by Directec) at 30 ° C. and 40% RH at a concentration of nitric oxide: 50 ppm and nitrogen dioxide: 50 ppm. For 4 days and evaluated by checking the image quality of the output image after exposure to NOx.
The image quality was determined according to the following index.
(Image quality evaluation criteria)
◎: Concentration exceeds 0.3 ○: Concentration exceeds 0.2 and 0.3 or less △: Concentration exceeds 0.1 and 0.2 or less ×: Concentration ranges from 0 to 0.1

From the results in Table 2, compounds having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic rings of the charge transporting compounds of Examples 1 to 10 were obtained using vinylsulfonic acid. An electrophotographic photosensitive member having a cross-linked charge transport layer (outermost surface layer) having a three-dimensional cross-linked polymer obtained by polymerization is excellent in abrasion resistance, excellent in mechanical durability, and has excellent electric potential with little decrease in dark portion potential. It can be seen that the electrophotographic photosensitive member has excellent characteristics, is excellent in environmental stability and gas stability, and has a long life.
In particular, the electrophotographic photoreceptors of Examples 1 to 5 are very excellent in environmental stability and gas resistance stability, and the electrophotographic photoreceptors of Examples 6 to 8 have a low bright part potential and charge transportability. It was excellent.

Comparative Example 1 using dodecylbenzenesulfonic acid as a curing catalyst has poor wear resistance and insufficient mechanical durability as compared with Example 1, and further shows an increase in bright part potential and a decrease in dark part potential. The image quality was inferior. Further, in Comparative Example 2 using a dodecylbenzenesulfonic acid having a molar concentration similar to that of the vinylsulfonic acid of Example 1, although the wear resistance is improved, the dark portion potential is decreased, and the image quality is It was greatly inferior.
Further, in Comparative Examples 3 and 4 using a cross-linked film of a charge transporting compound having a methylol group, the dark portion potential was lowered and the image quality was inferior.
Comparative Example 5 using paratoluenesulfonic acid as a curing catalyst had lower abrasion resistance and inferior mechanical durability than Example 9, and gas resistance was slightly lowered. Further, Comparative Example 6 using para-toluenesulfonic acid having a molar concentration similar to that of the vinyl sulfonic acid of Example 1 is equivalent in wear resistance and electrical characteristics, but the gas resistance stability is slightly reduced. The image quality was inferior.

  From the above, 3 obtained by polymerizing a compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound using vinylsulfonic acid as a curing catalyst. An electrophotographic photoreceptor having a dimensionally cross-linked surface polymer in the outermost surface layer has excellent mechanical durability, electrical characteristics, environmental stability, and gas resistance stability, and an image forming method using the electrophotographic photoreceptor. The image forming apparatus and the process cartridge for the image forming apparatus can continue to output high-quality image output for a long period of time, and in particular, can stably output high-quality images even in an environment where environmental changes occur. Can continue to output.

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Charge generation layer 3 Charge transport layer 5 Crosslinkable charge transport layer 6 Photosensitive layer (outermost surface layer)
7 Protective Layer 10 Electrophotographic Photoreceptor 10Y Electrophotographic Photoreceptor 10M Electrophotographic Photoreceptor 10C Electrophotographic Photoreceptor 10K Electrophotographic Photoreceptor 11 Charging Member 11Y Charging Member 11M Charging Member 11C Charging Member 11K Charging Member 12 Image Exposure Member 13 Developing Member 13Y Developing member 13M Developing member 13C Developing member 13K Developing member 15 Transfer paper 16 Transfer member 16Y Transfer member 16M Transfer member 16C Transfer member 16K Transfer member 17 Cleaning member 17Y Cleaning member 17M Cleaning member 17C Cleaning member 17K Cleaning member 23 Fixing member 24 Fixing Element

JP 2000-066425 A JP 2000-171990 A JP 2003-186223 A JP 2007-293197 A JP 2008-299327 A Japanese Patent No. 4262661 JP 2006-251771 A JP 2009-229549 A JP 2006-084711 A

Claims (10)

An electrophotographic photosensitive member having a conductive support and at least a photosensitive layer on the conductive support,
The electrophotographic photoreceptor has an outermost surface layer;
From the compound in which the outermost surface layer uses vinylsulfonic acid as a curing catalyst and has three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound, (Tetrahydro-2H-pyran-2-yl) oxy] An electrophotographic photoreceptor comprising a three-dimensional crosslinked polymer formed by polymerization through a reaction in which a part of a methyl group is cut off and eliminated.   The electrophotographic photoreceptor according to claim 1, wherein the three-dimensional crosslinked polymer is insoluble in tetrahydrofuran. The compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound is a compound represented by the following general formula (1): The electrophotographic photosensitive member according to any one of the above.
However, in said general formula (1), Ar < ₁ >, Ar < ₂ > and Ar < ₃ > represent the C6-C18 bivalent aromatic hydrocarbon group which may have an alkyl group as a substituent. The compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound is a compound represented by the following general formula (2): The electrophotographic photosensitive member according to any one of the above.
However, in the general formula (2), X ₁ is an alkylene group having 1 to 4 carbon atoms, an alkylidene group having 2 to 6 carbon atoms, and two alkylidene groups having 2 to 6 carbon atoms bonded via a phenylene group. Represents a divalent group or an oxygen atom, and Ar ₄ , Ar ₅ , Ar ₆ , Ar ₇ , Ar ₈ and Ar ₉ are divalent aromatics having 6 to 18 carbon atoms which may have an alkyl group as a substituent. Represents a group hydrocarbon group. The compound having three or more [(tetrahydro-2H-pyran-2-yl) oxy] methyl groups on the aromatic ring of the charge transporting compound is a compound represented by the following general formula (3): The electrophotographic photosensitive member according to any one of the above.
In the general formula (3), _{Y 1} represents a benzene, biphenyl, terphenyl, stilbene, distyryl benzene, or a divalent group of condensed polycyclic aromatic _{hydrocarbons,} Ar _{10, Ar} 11, Ar ₁₂ and Ar ₁₃ represent a C 6-18 divalent aromatic hydrocarbon group which may have an alkyl group as a substituent. The electrophotographic photosensitive member according to claim 3, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (1-1).
However, in said general formula (1-1), R < ₁ >, R < ₂ > and R < ₃ > may be the same or different, and represent a hydrogen atom, a methyl group, or an ethyl group, l, n and m represent an integer of 1 to 4. The electrophotographic photosensitive member according to claim 4, wherein the compound represented by the general formula (2) is a compound represented by the following general formula (2-1).
In the general formula (2-1), _{X 2 is, -CH 2 -, - CH 2} CH 2 -, - C (CH 3) 2 -Ph-C (CH 3) 2 -, - C (CH ₂ ) Represents _5- or -O-, and R ₄ , R ₅ , R ₆ , R ₇ , R ₈ and R ₉ may be the same or different, and may be a hydrogen atom or a methyl group Or an ethyl group, Ph represents a phenylene group, and o, p, q, r, s, and t represent an integer of 1 to 4. The electrophotographic photosensitive member according to claim 5, wherein the compound represented by the general formula (3) is a compound represented by the following general formula (3-1).
In the general formula (3-1), _{Y 2} represents a benzene, biphenyl, terphenyl, stilbene, or a divalent group of naphthalene. R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ may be the same or different and each represents a hydrogen atom, a methyl group or an ethyl group, and u, v, w and z are 1 to 1 Represents an integer of 4.   The photosensitive layer has at least a charge generation layer, a charge transport layer, and a crosslinked charge transport layer in this order, and the crosslinked charge transport layer is an outermost surface layer of the photosensitive layer. The electrophotographic photosensitive member according to any one of the above.   An electrophotographic photosensitive member; a charging unit that charges the surface of the electrophotographic photosensitive member; an exposing unit that exposes the surface of the charged electrophotographic photosensitive member to form an electrostatic latent image; and An image forming apparatus comprising at least a developing unit that develops a visible image using the developing unit, a transfer unit that transfers the visible image to a recording medium, and a fixing unit that fixes the transferred image transferred to the recording medium An image forming apparatus, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to claim 1.