JPH02133416A - Positive hole-transporting substance and electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To prepare a positive hole-transporting substance with improved positive hole-transporting properties, improved mechanical strengths and large dark resistance by copolymerizing a polysilane polymer and a polymer of an anionically polymerizable monomer. CONSTITUTION:An anionically polymerizable monomer (e.g., methyl methacrylate) is addition-polymerized to the active ends which are involved in the polymer growth reaction of a polysilane of the formula [wherein R<1>-R<6> are each (substd.) alkyl, (substd.) aryl, (substd.) alkoxy, (substd.) silyl, (substd.) silylidene, or (substd.) silylidyne; and m, n, and p are each a proportion of each monomer in the total polymer[ with a number-average degree of polymn. of 50000-100000 to give a positive hole-transporting substance comprising a polymer block (A) consisting of said polysilane and another polymer block (B) consisting of said anionically polymerizable monomer in a wt. ratio of A to B of (1:0.2)-(0.2:1). A carrier generating layer 2 contg. an inorg. or org. pigment and a carrier transport layer 3 contg. said positive hole-transporting substance are laminated on a conductive support layer 1 to give an electrophotographic photoreceptor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a hole transporting substance and an electrophotographic photoreceptor.

[Conventional technology]

As electrophotographic photoreceptors, inorganic photoreceptors comprising an inorganic photosensitive layer made of an inorganic photoconductive compound such as selenium, zinc oxide, or cadmium sulfide have been widely used.

However, such inorganic light absorbers are not necessarily fully satisfactory in terms of sensitivity, thermal stability, moisture resistance, durability, etc. For example, an inorganic photoreceptor comprising an inorganic photoreceptor layer made of selenium tends to crystallize at high temperatures and deteriorate its characteristics as an electrophotographic photoreceptor, so severe temperature conditions are required in the manufacturing process. Also, when handling it, it is necessary to avoid crystallization due to heat, fingerprints, etc.

Furthermore, inorganic photoreceptors including an inorganic photosensitive layer made of cadmium sulfide or zinc oxide have a problem of poor moisture resistance and durability.

Under these circumstances, in recent years, research and development of organic photoreceptors comprising an organic photosensitive layer made of an organic photoconductive compound has been actively conducted.

For example, in Japanese Patent Publication No. 50-10496, Bo IJ
N-vinylcarbazole (!:, 2. 4. 7-) IJ
It contains nitro-9-fluorenone! ! ff
An organic photoreceptor comprising an i-photolayer is disclosed. However, this organic photoreceptor is still insufficient in terms of sensitivity and durability.

In response, an organic photoreceptor has been developed that has a so-called functionally separated organic photoreceptor 1 in which the functions of generating carriers (holes or electrons) and transporting carriers (holes or electrons) are shared by different substances. It was done.

Such an organic photoreceptor has the advantage that the selection range of the material width constituting the photosensitive layer is greatly expanded, and organic photoreceptors having various performances can be produced relatively easily.

Therefore, various azo compounds have been put into practical use as carrier generating substances that share the role of carrier generating substances, and examples of azo compounds that share the carrier transport function include, for example, JP-A-51-94829, JP-A-5272231; No. 53 27033, No. 55-52063, No. 58-
This method has been proposed in various publications such as No. 65440 and No. 58-198425.

However, the organophotoreceptor constructed using the above-mentioned carrier transporting substance does not have a sufficiently high chiaria transport ability (particularly
However, when subjected to a high-speed copying process at a low environmental temperature, there is a drawback that sensitivity decreases or residual potential increases.

Under these circumstances, a technology using polysilane with a specific structure as a carrier (hole) transport material has recently been proposed (
(See Japanese Patent Application Laid-open No. 170747/1983).

Unlike the carrier transport substances mentioned above, this polysilane has self-forming properties, so it is possible to easily form a film-like photosensitive layer without combining it with Ike's Bainggu. The pore mobility is approximately IQ-'cm'/V
-sec, which is about one order of magnitude larger than the above-mentioned carrier-transporting materials. It can be resolved by using it.

[Problem to be solved by the invention]

However, photosensitive layers constructed using polysilane generally have low film strength, and therefore, when the electrophotographic process is repeatedly carried out, the surface is damaged by the abrasion force exerted by toner during development or cleaning members during cleaning, etc. Alternatively, the film may peel off, and as a result, defects such as white stripes and black stripes may occur early in the resulting copied image, resulting in a problem of deterioration of image quality. Another problem is that porinlan has a relatively low dark resistance, and organic photoluminescent materials constructed using it have insufficient charging ability.

On the other hand, the present inventor attempted to configure a photosensitive layer by combining polysilane and other polymers from the viewpoint of increasing the film strength of Photosensitive 1. It was found that due to poor solubility between the polymer and other polymers, phase separation occurred and sufficient performance was not exhibited.

The present invention has been made based on the above circumstances, and its objects are as follows.

(1) To provide a hole-transporting substance that has excellent hole-transporting properties, excellent mechanical strength, and high dark resistance.

(2) To provide an electrophotographic photoreceptor having excellent charging characteristics and sensitivity characteristics as well as excellent mechanical durability.

[Means to solve the problem]

In order to achieve the above object, the hole transporting substance of the present invention is
It is characterized by being composed of a block copolymer of a polymer block A made of porinlan and a polymer block B made of a polymer of an anionically polymerizable monomer.

Further, it is preferable that the porinlan is represented by the following general formula (a).

General formula (a) (wherein R1, R2, R3, R4, R5, and R6 are hydrogen, an alkyl group or a substituted alkyl group, an aryl group or a substituted aryl group, an alkoke group or a substituted alkoke group, an nryl group or a substituted silyl group) m represents a silylidene group, a substituted silylidene group, a silylizoin group, or a substituted silylidene group, and may be the same or different.

n and p represent the proportion of each monomer unit in the total polymer. ) Moreover, the number average degree of polymerization of porinlan is 10 to 50.000.
It is preferable that

In addition, styrene, α-methylstyrene, acrylic ester, methacrylic ester, imprene, substituted isoprene, butadiene, substituted butadiene, acrylonitrile, methacrylonitrile, methyl vinyl ketone,
Preferably, it is one or more selected from alkyl vinyl ketones such as α-methyl methyl vinyl ketone.

Further, the polymer of the anionically polymerizable monomer may have a crosslinked bond.

In addition, the weight ratio A/W of polymer block A and polymer block B in the block copolymer is 1702 to 0.2/
It is preferable that it is 1.

The electrophotographic photoreceptor of the present invention is characterized by comprising an organic photosensitive layer containing the above-mentioned specific hole-transporting substance.

[Effect]

The hole-transporting substance of the present invention is composed of a block copolymer of a polymer block A made of polysilane and a polymer block B made of a polymer of an anionic polymerizable monomer. Since these are chemically bonded to each other, the polymer block A made of porinlan exhibits excellent hole transport properties without causing the problem of phase separation of each polymer block, and the anionic polymerizable monomer The polymer block made of the above polymer provides sufficient mechanical strength and sufficient dark resistance.

According to the electrophotographic photoreceptor of the present invention, the electrophotographic photoreceptor contains the above-mentioned specific hole-transporting substance (because it grows the photosensitive layer, it exhibits excellent charging characteristics and sensitivity characteristics). At the same time, the mechanical strength of the photosensitive material becomes sufficient, and even when the electrophotographic process is repeated, it becomes possible to stably form good images many times.

[Specific content of the invention]

Hereinafter, the hole transporting substance and electrophotographic photoreceptor of the present invention will be specifically explained.

[1] Hole-transporting substance The hole-transporting substance of the present invention consists of a block copolymer of a polymer block A made of porinran and a polymer block B made of a polymer of an anionically polymerizable monomer. be.

Polymer block A> Polysilane forming the groove bottom of polymer block A is carbon (C)
It is a general term for organic substances whose main skeleton is silicon (Sl) instead of silicon (Sl), and specifically includes various polymers.

Preferred examples of such polysilanes include homopolymers, copolymers, and terpolymers represented by the following general formula (a).

General formula (a) (wherein R', R', R3, R', R5, R6 are hydrogen, an alkyl group or a substituted alkyl group, an aryl group or a substituted aryl group, an alkoxy group or a substituted alkoxy group, a silyl group) or represents a substituted allyl group, a silylidene group, a substituted silylidene group, a silylizoin group, or a substituted arylidine group, and may be the same or different.

n and p represent the proportion of each monomer unit in the total polymer. ) The number average degree of polymerization of the polymer block A made of such polysilane is preferably 10 to 50.000. Moreover, each monomer unit of polysilane may be distributed randomly throughout the polymer block A, or may be distributed in a block shape.

The alkyl group constituting the general formula (a) is a linear or branched alkyl group having 1 to 24 carbon atoms, preferably 1 to 8 carbon atoms, such as a methyl group, ethyl group, propyl group, butyl group, and amyl group. , cycloalkyl groups such as hexyl group, octyl group, nonyl group, decyl group, pentadecyl group, stearyl group, and cyclohexyl group, unsaturated alkyl groups including allyl group, and substituted alkyl groups thereof. Particularly preferred alkyl groups are methyl group,
These are ethyl group, propyl group, and butyl group.

Examples of the aryl group include those having preferably 6 to 24 carbon atoms, phenyl group, naphthyl group, anthryl group, and the like.

The alkoxy group preferably has 1 to about 10 carbon atoms, and includes, for example, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and the like.

Substituted alkyl group, substituted aryl group, substituted alkokyne group,
Examples of the substituents in the substituted silyl group, the substituted silyl group, and the substituted lyridine group include an alkyl group, an aryl group, a halogen atom, a nitro group, an amine group, an alkokene group, a cyan group, and other substituents. .

For example, as a substituted silyl group, Si H(CH=) 2
-5i(CH3)--1s1(C2H,, ), -1S
i(C-R7)3-3i (C4R9) :l-1Si
(CH,)2(C2H5)-1Si (CH3)(C,
H,, ), -1S+(CH3)-(CsR3)-1Si
(CH,)2(C,H,CH2>-, etc. Also, for example, substituted
(CH,)gu, St (CHz) 2ku, 5i (CzHs)
2gu, 5i (C3H7), 5i (C, H=)2ku,
Si (CR3) (C-R5), Si (CR3)
(Cs Hs) Ri, St (CR3) (C6H,
C1(2), etc. Also, for example, as a substituent IJ lysoin group, 5iH
(, St(Cth) EE, Si (C21(s) E
, 5t (CaHl), 5i (CIIHs), St (
C6Hs CR2) EIE, etc.
These silylidene groups and iriridine groups are bonded to silylidene groups and silylizoin groups of the same polymer block or other polymer blocks.

Specific examples of such polysilanes include polycyclotrimethylenesilane, polycyclopentamethylenesilane, poly2-acetoxyethylmethyl/lane, polytert-butylmethylsilane, poly-t-butylsilane-codimethylsilane, and polymethylphenylenesilane. N-codimethylsilane, polycyanoethylmethylsilane, polyn-propylmethylsilane, polyp-tolylmethylenesilane, polycyclohexylmethylsilane, polycyclotetramethylenesilane, poly2-carbomethoxyethylmethylsilane, polyphenylethylsilane, polysilane Examples include nienylsilane-cophenylmethylsilane.

<Polymer block B> The anionic polymerizable monomer constituting the polymer of polymer block B is not particularly limited as long as a polymer with high mechanical strength can be obtained, but specifically, styrene-based, Can be selected from alkyl vinyl ketones such as α-methylstyrene, acrylic ester, methacrylic ester, isoprene, substituted isoprene, butadiene, substituted butadiene, acrylonitrile, methacrylonitrile, methyl vinyl ketone, α-methyl methyl vinyl ketone, etc. preferable.

The polymer of polymer block B may be formed from a single monomer, or may be formed from two or more types of monomers.

Specific examples of the polymer of the polymer block B include polymethyl methacrylate, polystyrene, polyα
-Methylstyrene, polymethylacrylate, polyisoprene, polybutadiene, polyacrylonitrile, polymethacrylonitrile, polymethylvinylketone, polyα
-Methyl methyl vinyl ketone and the like.

Furthermore, the polymer of polymer block B may be crosslinked in advance with a crosslinking monomer or by its own reaction before forming the block copolymer. By having such a crosslinking bond, it becomes possible to further increase the mechanical strength of the hole transporting substance.

As a crosslinking monomer for forming such a crosslinking bond, for example, when a double bond remains on the polymer block,
Styrene, α-methylstyrene, p-methoxystyrene, acrylic ester, methacrylic ester, acrylonitrile, methacrylonitrile, butadiene, isoprene, etc. can be used, and if other functional groups remain, between the functional groups Various polyfunctional compounds that crosslink can be used. For example, if the remaining functional group is isocyanate, polyamines, polyols, etc. can be used, and if epoxy groups remain, polyols, polyamines, polymercaptan neck, polybasic acids, etc. can be used. can.

In addition, in the formation of a crosslinking bond, after forming a block copolymer, a crosslinking monomer and a polymerization initiator used as necessary are added to a coating solution for forming a photosensitive layer containing the block copolymer, and this is coated. It is preferable to crosslink the polymer blocks B by heating or the like afterwards.

Block Copolymer> The hole-transporting substance of the present invention can be formed by forming a block copolymer with the above polymer block and polymer block B, but the polymerization method is not particularly limited. in particular,
The following methods can be applied.

(1) After preparing polymer block A, a specific functional group at the end of its molecular chain is reacted with a specific functional group of separately prepared polymer block B, or by elimination of both of these functional groups. A method of forming block copolymers by condensation.

(2) A method in which, following the reaction for preparing polymer block A, an anionically polymerizable monomer is added to the active terminal that participates in the growth reaction of polymer block A that maintains its activity.

The above two methods are conceivable, but since it is practically difficult to intentionally introduce a specific functional group to the end of each polymer block, method (2) above is recommended.

The weight ratio Δ/B of polymer block A and polymer block B in the block copolymer is preferably 110.2 to 0.2/1. If the polymer block A is too small, the sensitivity characteristics will deteriorate, while if the polymer block B is too small, the film formability, mechanical strength and charging characteristics will be insufficient. That is, polymer block A greatly contributes to improving sensitivity characteristics due to the characteristics of polysilane, and polymer block B greatly contributes to improving film formability, mechanical strength, and charging characteristics.

In addition, in preparing the photosensitive layer coating solution, a solvent may be added or may not be used. In addition, a crosslinking monomer is added to the coating liquid as necessary, and a crosslinking reaction initiator is further added to form a coating film before the liquid hardens, and this is dried and cured with heat or light to form crosslinking grooves. It is possible to form a synthetic film.

Examples of such crosslinking reaction initiators include benzoyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, azobutyronitrile, and dicucyl peroxide.

[2] Electrophotographic photoreceptor The electrophotographic photoreceptor of the present invention comprises an organic photosensitive layer containing the above-mentioned specific hole-transporting substance.

That is, the electrophotographic photoreceptor of the present invention basically has a functionally separated organic photosensitive layer composed of a combination of the specific hole-transporting substance and a carrier-generating substance, and this organic photosensitive layer is directly formed. Alternatively, it is constructed by laminating, for example, on a conductive support with another layer interposed therebetween.

The specific structure of the organic photosensitive layer is not particularly limited, and various structures as described below are possible.

(1) A configuration in which the carrier transport layer and the carrier generation 1 are separate and independent layers (hereinafter referred to as "configuration (1)").

(2) A structure in which a carrier-generating substance is dispersed and contained in the specific hole-transporting substance described above without forming an independent carrier-generating layer (hereinafter referred to as "Structure (2)").

According to such a functionally separated organic photosensitive layer, carrier generation and carrier transport are handled by separate substances, so carrier generation substances can be selected from a wide range, and the characteristics required in the image forming process can be met. Therefore, it is possible to construct an organic photoreceptor having excellent properties such as a high surface potential when charged, high photosensitivity, and high stability in repeated use.

Since the specific hole-transporting substance of the present invention has high film-forming properties by itself, it is possible to form a carrier transport layer in the above structure (1) or in the above structure (2) without using a binder. A photosensitive layer can be formed.

The carrier transport layer in the above configuration (1) or the photosensitive layer in the above configuration (2) may be formed only of the specific hole transport substance described above, or may be formed as necessary to impart desired characteristics. Other substances may be used in combination depending on the situation. Examples of such other substances include the following:

(1) Binder for increasing insulating properties As such a binder, one that has insulating properties and is compatible with the specific hole-transporting substance described above may be used. Specifically, for example, polycarbonate, polyester, methacrylic resin, acrylic resin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, polyisoprene, polybutadiene, polyamide resin, polyurethane resin, such as styrene-butadiene-tHj combination,
Styrene copolymer resins such as styrene-methyl methacrylate copolymer, acrylonitrile copolymer resins such as vinylidene chloride acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride Copolymer, silicone resin, silicone
Examples include alkyd resins, phenolic resins, styrene-alkyd resins, polyvinyl butyral, polyvinyl formal, and polyhydroxystyrene. These binders can be used alone or in combination of two or more. The proportion of such a binder used in combination is, for example, about 5 to 50% by weight of the carrier transport layer in the above structure (1) and the photosensitive layer in the above structure (2) other than the carrier generating substance.

(2) Other n-type carrier transport substances for reducing residual potential Examples of such n-type carrier transport substances include tetraanoethylene, tetracyanoquinodimethane, dichlorodicyanobarabenzquinone, Examples include trinitrofluorenone, tetranitrofluorenone, fluorenylidene malonocinitrile, annealed compounds, and the like. Such a carrier transport substance can also be added to the carrier generation layer in the above structure (1).

The carrier-generating substance is not particularly limited as long as it absorbs visible light to infrared light to -111Q and generates free carriers, but specifically, it can be selected from inorganic pigments, organic pigments, etc. can.

Examples of such inorganic pigments include amorphous selenium, trigonal selenium, selenium-arsenic alloy, selenium-tellurium alloy, and cadmium sulfide.

In addition, examples of organic pigments include (1) monoazo pigments,
Azo pigments such as bisazo pigments, trisazo pigments, and metal complex azo pigments, (2) perylene pigments such as perylene acid anhydride and perylene acid imide, (3) anthraquinone derivatives,
Polycyclic quinone pigments such as anthanthrone derivatives, dibenzpyrenequinone transparent conductors, pyranthrone derivatives, violanthrone derivatives, isoviolanthrone derivatives, (4) indigoid pigments such as indigoid derivatives and thioindigoid derivatives, (5) metal phthalocyanine, Examples include phthalocyanine pigments such as metal-free phthalocyanine.

Such a carrier-generating substance has poor film-forming properties by itself, so when forming a separate carrier-generating layer, it is preferable to use a binder together.

The binder used in the above vA formation (1) is not particularly limited, but it is preferable to use, for example, a high molecular weight polymer that is hydrophobic and capable of forming an insulating film. . As such a high molecular weight polymer, the same substances as those exemplified as the binder for enhancing insulation can be used. These binders can be used alone or in combination of two or more. Such a binder is one of the carrier generating substances.
It is preferable to use it in a range of 1 part by weight or less based on 5 parts by weight.

As the conductive support, for example, the following can be used, but it is not limited thereto.

(1) A plate-shaped or drum-shaped conductive support made of metal such as aluminum or stainless steel.

(2) A thin film made of metal such as aluminum, palladium, or gold on a support such as paper or plastic film.
A conductive support having a structure provided by laminating or vapor deposition.

(3) A conductive support comprising a support such as paper or a plastic film, and a layer of a conductive compound such as a conductive polymer, indium oxide, or tin oxide provided by coating or vapor deposition.

Next, a specific example of the structure of the electrophotographic photoreceptor according to the present invention will be described with reference to the drawings.

FIG. 1 shows a structure in which a carrier generation layer 2 is laminated on a conductive support 1, and a carrier transport layer 3 containing the above-mentioned specific hole transport substance is further laminated thereon. This is an example of an electrophotographic photoreceptor.

In this example, a carrier generation layer 2 and a carrier transport layer 3, which are independent from each other, constitute a multi-layer optical system.

FIG. 2 shows the carrier generation layer 2 and the carrier generation layer 2 in the example of FIG.
This is a configuration in which the stacking order of the carrier transport layer 3 is reversed.

FIG. 3 shows t! in which an intermediate layer 5 is added between the carrier generation layer 2 and the conductive support 1 in the example of FIG. 1! It is four generations. This intermediate layer 5 functions as, for example, an adhesive layer, a barrier, and the like.

FIG. 4 shows a configuration in which an intermediate layer 5 is added between the carrier transport layer 3 and the conductive support 1 in the example shown in FIG. 2, and an overcoating 18 is further provided on the carrier generation layer 2. It is. This overcoating layer 8 is provided as necessary.

FIG. 5 shows a single-layer organic photosensitive layer 4 formed by dispersing fine particulate carrier-generating substances 7 in a layer 6 containing a hole-transporting substance, on a conductive support 1. detective 3
This is the configuration.

The fifth example has a configuration in which an intermediate layer 5 is added between the organic optical hole layer 4 and the conductive support 1 in the 511th example.

When the organic photosensitive layer 4 has a multilayer structure including the carrier generation layer 2 and the carrier transport layer 3, which of the carrier generation layer 2 and the carrier transport layer 3 is used as the upper layer depends on the charge polarity of the rocky landscape layer 4. It is preferable to define it based on.

That is, when the charge polarity is negative, it is advantageous to use earth and stone as the carrier transport layer 3, as shown in FIGS. 1 and 3.

The means for forming the key carrier transport layer 3 is not particularly limited, but specifically, dip coating? Various methods can be applied, such as spray coating, blade coating, roll coach ink, laminating, and melt extrusion.

That is, since the specific hole-transporting substance described above exhibits sufficient solvent solubility, the carrier-transporting layer can be formed by applying a normal coating method.

Moreover, a crosslinking monomer may be added to the coating liquid as necessary, and a crosslinking reaction initiator may also be added thereto.

In this case, a strong carrier transport layer 3 having a crosslinked structure can be formed.

The thickness of the carrier transport layer 3 can be changed as necessary, but is usually about 2 to 50 μm, preferably about 5 to 50 μm.
It is about 30 μm scraps.

The method of forming the carrier generation layer 2 is not particularly limited, but specific examples include: 1) a vacuum evaporation method, 2) a method of applying a solution of a carrier-generating substance dissolved in an appropriate solvent, and 2) a method of applying a carrier-generating substance to a ball mill or a sand grinder. It is possible to apply a method such as forming the particles into fine particles in a dispersion medium by, for example, applying a dispersion obtained by mixing the particles with a binder as necessary.

The thickness of such carrier-generated N2 is usually 0.01 to 10
The amount is approximately 0.05 to 5 μm, preferably approximately 0.05 to 5 μm.

In addition, as shown in FIG. 5 or FIG. 6, when the photosensitive layer 4 is constituted by dispersing a fine particulate carrier-generating substance 7 in a layer 6 containing a hole-transporting substance, The content of the carrier-generating substance 7 is preferably 10 to 90% of the photosensitive layer 4.

The intermediate layer 5 functions as an adhesive layer or a barrier layer, and specifically, in addition to the substances already mentioned as binders used in the carrier generation layer, for example, polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose, casein, etc. etc. can be configured.

For the overcoating layer 8, a resin used as a binder for the carrier generation layer can be used. In addition, in order to assist the movement of carriers in the layer, the above-mentioned n-type carrier transport substances, pyrazoline derivatives, benzidine derivatives, oxazole derivatives, oxadiazole derivatives, polyphenylamine derivatives, styrylamine derivatives, hydrazones, etc. may be used. It is preferable to use a mixture of p-type carrier transport substances. The thickness of this overcoating layer 8 is preferably about 0.1 to 10 μm, particularly preferably 0.5 to 5 μm.

〔Example〕

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

<Example 1> (1) Sufficiently purified and dehydrated tetrahydrofuran 100-
In a dry nitrogen atmosphere, 30.8 g of biphenyl (
0.2 mol) and further 2.8 g of metallic lithium (
0.4 mol) and stirred at room temperature for 2 hours, followed by Dr.
y Icl-! It was cooled to -78°C by the Jethanol method.

Next, a solution of 18.7 g (0.1 mol) of 1,1,2,2-tetramethyl-1,2-dichlorodisilane dissolved in 50 ml of purified and dried tetrahydrofuran was added to the above cooled solution. It was gradually added dropwise while stirring. After stirring for 2 hours, 1 mE of a 0.1 mol/β hexane solution of butyllithium was gradually added dropwise while stirring vigorously while keeping the temperature at -78°C.

Through the above treatment, a solution containing a polymer block A made of polydimethylsilane having an active end (-3i0) with a number average molecular weight of 116,000 and a degree of polymerization of 2000 was obtained.

(2) Next, methyl methacrylate) 20 g (0,
A solution prepared by dissolving 100 ml of dry tetrahydrofuran (2 mol) was gradually added dropwise to the solution containing the polymer block A kept at -78°C under vigorous stirring.

Through the above treatment, a solution containing a hole-transporting substance made of a pro-7 copolymer of polymer block 8 made of polydimethylsilane and polymer block B made of polymethyl methacrylate with a degree of polymerization of 2000 was obtained. Ta.

<3) Next, He-Hisan was added to the solution containing the above-mentioned hole-transporting substance, and the precipitate was taken out. This precipitate was again dissolved in tetrahydrofuran, and then hexane was added again to take out the precipitate. By this operation, biphenyl was removed.

Thereafter, lithium and chlorine were removed from the precipitate by Soxhlet extraction using methanol, thereby obtaining a purified hole-transporting substance.

<Example 2> (1) In Example 1, 1. 1. 2. Instead of 2-tetramethyl-1,2-dichlorodisilane, 1.
A polymer block 8 consisting of polydi-n-butylsilane was prepared in the same manner except that 35.5 g (0.1 mol) of 1,2.2-tetra-n-butyl-1,2-dichlorodisilane was used. A solution was obtained.

(2) Polymerization with polymer block A consisting of polydi-n-butylsilane was carried out in the same manner as in Example 1, except that 28.4 g (0.2 mol) of butyl methacrylate was used instead of methyl methacrylate. A solution containing a hole-transporting substance made of a block copolymer with polymer block B made of polybutyl methacrylate having a polybutyl methacrylate of 2000 was obtained.

(3) In the same manner as in Example 1, a fitted hole transport material was obtained.

<Example 3> (1) In the same manner as in Example 1, a solution containing polymer block 8 made of polydimethylsilane was obtained.

(2) In the same manner as in Example 1, except that 1.8 g (0.2 mol) of styrene 2C was used instead of methyl methacrylate, polymer block 8 made of polydimethylsilane and polystyrene with a degree of polymerization of 2000 were prepared. A solution containing a hole-transporting substance made of a block copolymer with polymer block B was obtained.

(3) Tetrahydrofuran was added to the solution containing the hole transporting substance to dissolve the hole transporting substance.

Furthermore, methanol was added to cause precipitation, and the precipitate was taken out. This precipitate was again dissolved in tetrahydrofuran, methanol was added again to form a precipitate, and the precipitate was taken out. Through this operation, impurities such as biphenyl and lithium ions were removed, thereby obtaining a purified hole transporting substance.

<Example 4> (1) In the same manner as in Example 1, a solution containing polymer block 8 made of polydimethylpuran was obtained.

(2) In the same manner as in Example 1, except that 3.4 g (0.05 mol) of isoprene was used instead of methyl methacrylate, a polymer block Δ made of polydimethylsilane and a polyisoprene with a degree of polymerization of 500 were used. A solution containing a hole-transporting substance made of a block copolymer with polymer block B was obtained.

(3) A purified hole-transporting substance was obtained in the same manner as in Example 1.

<Example 5> (1) In the same manner as in Example 1, a solution containing a polymer film Δ made of polydimethylsilane was obtained.

(2) Next, a mixture of m-isopropenyl-α-α-dimethylbenzylisocyanate (TMI), n-butyl acrylate, and methyl methacrylate (in a weight ratio of 1:
20:29) 100rrf of 50g of dry purified tetrahydrofuran! The prepared solution was added to the solution containing the polymer block A, which was kept at a temperature of -78°C, and stirred for a while.

Through the above treatment, polymer block A and TMl-n-
A solution containing a hole-transporting substance made of a block copolymer with polymer block B made of a butyl acrylate-methyl methacrylate copolymer was obtained.

(3) A purified hole-transporting substance was obtained in the same manner as in Example 1.

<Example 6> A 0.0 mm thick film made of vinyl chloride-vinyl acetate-maleic anhydride copolymer [S-LEC MF-10J (manufactured by I-Sui Kagaku Co., Ltd.)] was placed on a conductive support consisting of a cylindrical aluminum drum. An intermediate layer with a thickness of 1 μm was provided.

1 part by weight of dibrome anthron "Monolite Red 2YJ (manufactured by ICr), which is represented by the structural formula (■) below,
Polycarbonate resin "Panlite L-1250J"
(manufactured by Kijin Kasei Co., Ltd.) in 100 parts by weight of 12-dichloroethane and dispersed in a ball mill for 24 hours to prepare a coating solution. A carrier generation layer having a thickness of 0.5 g after drying was formed on top.

Next, a coating solution was prepared by dissolving the hole-transporting substance obtained in Example 1 in tetrahydrofuran, and this coating solution was applied onto the carrier generation layer by a dipping method so that the film thickness after drying became uniform. A carrier transport layer having a thickness of 20 μm was formed, thereby producing an electrophotographic photoreceptor according to the present invention.

Structural formula ■ (Evaluation) The above electrophotographic photoreceptor was transferred to an electrophotographic copying machine rl-Bix.
7090J (manufactured by Konica ■) was installed in a modified machine, and the surface of the electrophotographic photoreceptor was charged to negative polarity using a Scorotron charger (grid voltage -5 kV).

Next, an electrostatic latent image was formed on the electrophotographic photoreceptor by imagewise exposure using a black and white chart image.

This electrostatic latent image was developed with a toner consisting of 95% by weight of styrene-methyl methacrylate-〇-butyl methacrylate copolymer and 5% by weight of carbon black.

Next, the toner image obtained by development was transferred onto plain paper and fixed to form a copy image.

On the other hand, toner remaining on the electrophotographic photoreceptor after transfer was cleaned using a blade type cleaning device.

The image forming process was repeated 10,000 times at environmental temperatures of 25° C. and 0° C., and the performance of the electrophotographic photoreceptor was evaluated. Note that the linear velocity of the surface of the electrophotographic photoreceptor is 44
It was set to 0 mm/sec. The results are as follows.

(1) The potential fluctuations in the black image area and white image area at the 1st and 10,000th cycles are extremely small, 15V and 15V at an environmental temperature of 25°C, and 120V and 15V at an environmental temperature of 0°C, respectively, resulting in excellent charging. It was confirmed that the characteristics were stably exhibited.

(2) At both the 1st and 10,000th times, the reflection density of the black image area is sufficiently high at 1.3 or more at any environmental temperature, and the reflection density of the white image area is sufficiently high at 0.01 or less. It was confirmed that the electrification characteristics were low and the sensitivity characteristics were stable.

(3) From the first to the 10,000th printing, the reproducibility of the chart image was excellent, and no defects such as white streaks or black streaks caused by damage to the electrophotographic magazine light body were observed. Also, 1
After 10,000 times, when the surface of the electrophotographic photoreceptor was observed using a magnifying glass, no damage such as scratches or film peeling was observed. This is because the mechanical strength of the electrophotographic photoreceptor is 1
This is presumed to be because it can sufficiently withstand the abrasion force caused by toner, cleaning blades, and the like.

Comparative Example 1 A comparative electrophotographic photoreceptor was produced in the same manner as in Example 6, except that the carrier transport layer was formed as described below.

(Formation of carrier transport layer) In Example 1, (1) was added to the solution obtained in the process (1).
A coating solution was prepared by dissolving the polymer block 8 made of boridimethylanran obtained by the treatment in 3) in tetrahydrofuran, and using this coating solution, a carrier having a film thickness of 20 am after drying was prepared by a dipping method. A transport layer was formed.

(Evaluation) When the same test as in Example 6 was conducted using the comparative electrophotographic photoreceptor at an ambient temperature of 25° C., the following results were obtained.

(1) The potential fluctuations in the black image area and white image area at the 1st and 10,000th times were as small as -20V and -10V, respectively.
There was no significant difference from Example 6.

(2) The density of the white image area was almost the same as that of Example 6, but the density of the black image area was lower than 0.6 throughout, and the charging characteristics were lower than that of the electrophotographic photoreceptor of Example 6. It was inferior.

(3) Many black lines were observed in the 10,000th copied image. When the surface of the electrophotographic photoreceptor in the area where the black streaks were observed was observed using a magnifying glass, it was found that damage such as cracks and film peeling had occurred. This is presumed to be because the carrier transport layer has low mechanical strength and is easily damaged by abrasion forces caused by toner, cleaning blades, and the like.

<Comparative Example 2> In Example 6, 5 parts by weight of a carrier transporting substance represented by the structural formula (2) shown below and 5 parts by weight of polycarbonate resin "Panlite L-1250J" as a binder were added to 1.
A carrier transport layer having a dry film thickness of 20 JIN was formed by dip coating using a solution dissolved in 100 parts by weight of 2-dichloroethane to prepare a comparative electrophotographic photoreceptor.

Structural Formula ■ (Evaluation) When the same test as in Example 6 was conducted using the electrophotographic photoreceptor for comparison, the following results were obtained.

(1) The potential fluctuations in the black image area and white image area at the 1st and 10,000th times are 40V and 7V, respectively, at an environmental temperature of 25℃.
110V and 200V respectively at 0VSil ambient temperature 0℃
It was confirmed that V was extremely large.

(2) The reflection density of the black image area was 1.3 or higher throughout, but the reflection density of the white image area was 0 at the first time at an environmental temperature of 25°C.
．． 2. 1st time is 0.35, 1st time is 0 at environmental temperature 0℃
．． At the 351,000th time, the density was 0.45, which was a large variation and fogging occurred.

(3) No defects such as streaks caused by damage to the electrophotographic photoreceptor were observed in the copied images from the first to the 10,000th copy.
The mechanical strength of the electrophotographic photoreceptor against the abrasion force caused by the toner spray IJ-ning blade was almost the same as that of Example 6.

<Example 7> An electrophotographic photoreceptor of the present invention was prepared in the same manner as in Example 6, except that the carrier transport layer was formed using the hole transport material obtained in Example 2 as the hole transport material. Created.

(Evaluation) When the same test as in Example 6 was conducted using the above electrophotographic photoreceptor, similar good results were obtained.

<Example 8> In Example 6, a mixture of the hole-transporting substance obtained in Example 5 and brene glycol (weight ratio: 50:0.46 (twice that of 1)) was used as the hole-transporting substance. An electrophotographic photoreceptor of the present invention was produced in the same manner except that a carrier transport layer was formed using the following.

(Evaluation) When the same test as in Example 6 was conducted using the above electrophotographic photoreceptor, similar good results were obtained.

<Example 9> In Example 6, the carrier generation layer was formed as follows, and the carrier transport layer was formed using the hole transporting substance obtained in Example 3 as the hole transporting substance. An electrophotographic photoreceptor of the present invention was produced in the same manner.

(Carrier generation layer) 1 part by weight of bisazo pigment represented by the structural formula (■) below and 0.5 part by weight of polycarbonate resin "Panlite L-1300J (manufactured by Kijin Kasei Co., Ltd.) were mixed with 100 parts by weight of tetrahydrofuran.
A coating solution is prepared by dispersing in a ball mill for 24 hours, and this coating solution is used to form a carrier generation layer with a thickness of 0.4μ after drying on the intermediate layer by a dipping method. did.

Structural Formula ■ (Evaluation) When the same test as in Example 6 was conducted using the above electrophotographic photoreceptor, the following results were obtained.

(1) The potential fluctuations in the black image area and white image area at the 1st and 10,000th times are -30V and -10V, respectively, at an environmental temperature of 25°C, E! It was confirmed that the ambient humidity temperature was extremely low at 0°C -40V and -10V, and excellent charging characteristics were stably exhibited.

(2) At both the 1st and 10,000th times, the reflection density of the black image area was sufficiently high at 1.3 or more at any environmental temperature, and the reflection density of the white image area was 0.01 or less, which was sufficiently high. It was confirmed that the chargeability was low, and that excellent charging characteristics and excellent sensitivity characteristics were stably exhibited.

(3) From the first to the 10,000th printing, the reproducibility of the chart image was excellent, and no defects such as white streaks or black streaks caused by damage to the electrophotographic photoreceptor were observed. Also, 1
When observing the surface of the electrophotographic photoreceptor with a magnifying glass after 10,000 times, scratches and
No damage such as sniffles was observed, and it was confirmed that the electrophotographic photoreceptor had high mechanical strength.

<Example 10> The electrophotographic photosensitive material of the present invention was produced in the same manner as in Example 9 except that the carrier transport layer was formed using the hole transport material obtained in Example 4 as the hole transport material. was created.

(Evaluation) When the same test as in Example 6 was conducted using the above-mentioned electrophotographic photoreceptor, almost the same good results as in Example 9 were obtained.

<Example 11> A layer of vinyl chloride-vinyl acetate-maleic anhydride copolymer "S-LEC MF-IOJ (manufactured by Tsukisui Kagaku Co., Ltd.)" was placed on a conductive support formed by vapor-depositing aluminum on a polyester film. An intermediate layer of 0.1 VJM was provided.

Next, a coating solution was prepared by dissolving the hole-transporting substance obtained in Example 1 in tetrahydrofuran, and this coating solution was applied onto the intermediate layer by a dipping method so that the film thickness after drying was 20.
A μ-fake carrier transport layer was formed.

1 part by weight of a carrier-generating substance represented by the structural formula ■ below,
11 parts of the hole-transporting substance obtained in Example 1 were mixed with 50 parts by weight of tetrahydrofuran, and 2
The coating solution was dispersed for 4 hours, and then the coating solution was used to form a carrier-generated layer with a dry film thickness of 5 ua on the carrier transport layer by a spray method, thereby producing an electrophotographic image according to the present invention. A four-light body was created.

Structural formula■ (Evaluation) Using the electrophotographic photoreceptor described above, the environment was carried out in the same manner as in Example 6, except that the charging voltage was changed to kilo kV and the toner was changed to a negatively chargeable toner mainly composed of polyester. temperature 2
Tests were conducted at 5°C.

The results are as follows.

(1) The potential fluctuations in the black image area and the white image (stepped area) at the 1st and 10,000th times were extremely small at 50 V and 20 V, respectively, and excellent charging characteristics were stably exhibited.

(2) The density of the black image area and the white image area was as good as in Example 6 until 10,000 times.

(3) Up to 10,000 times, the reproducibility of the chart image was good, no image defects were observed, and there was no damage to the electrophotographic photoreceptor.

〔Effect of the invention〕

As explained in detail above, according to the hole transporting substance of the present invention, polymer block 8 is made of polysilane, and polymer block B is made of a polymer of an anionic polymerizable monomer.
It has excellent hole transport properties, excellent mechanical strength, and large dark resistance.

Further, according to the electrophotographic photoreceptor of the present invention, since it is provided with an organic photosensitive layer containing the above-mentioned specific hole-transporting substance, excellent charging properties can be obtained even when electrophotographic processes are repeatedly carried out. In addition to exhibiting excellent characteristics and sensitivity characteristics, it is possible to stably form images with excellent durability and reproducibility over many times.

[Brief explanation of drawings]

1 to 6 are explanatory cross-sectional views showing specific structural examples of the electrophotographic photoreceptor of the present invention, respectively. 1... Conductive support 2... Carrier generation layer 3
...Carrier transport number 4...Photosensitive layer 5...Intermediate layer 6...Layer containing a carrier transport substance 7...Carrier generating substance 8...Overcoat ink layer Figure 2 Figure 16

Claims (7)

[Claims] (1) A hole-transporting substance comprising a block copolymer of a polymer block A made of polysilane and a polymer block B made of a polymer of an anionically polymerizable monomer. (2) The hole-transporting substance according to claim 1, wherein the polysilane is represented by the following general formula (a). General formula (a) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^1, R^2, R^3, R^4, R^5, R
^6 is hydrogen, an alkyl group or a substituted alkyl group, an aryl group or a substituted aryl group, an alkoxy group or a substituted alkoxy group, a silyl group or a substituted silyl group,
It represents a silylidene group, a substituted silylidene group, a silylidene group, or a substituted silylidene group, and may be the same or different. m, n, p represent the proportion of each monomer unit in the total polymer. ) (3) Number average degree of polymerization of polysilane is 10 to 50,000
The hole-transporting substance according to claim 2, wherein the hole-transporting substance is (4) The anionic polymerizable monomer is styrene, α-methylstyrene, acrylic ester, methacrylic ester, isoprene, substituted isoprene, butadiene, substituted butadiene, acrylonitrile, methacrylonitrile, methyl vinyl ketone, α-methyl methyl vinyl The hole-transporting substance according to any one of claims 1 to 3, characterized in that it is one or more selected from alkyl vinyl ketones such as ketones. (5) The hole-transporting substance according to any one of claims 1 to 4, wherein the polymer of the anionically polymerizable monomer has a crosslinked bond. (6) The weight ratio A/B of polymer block A and polymer block B in the block copolymer is 1/0.2 to 0.2/
1. The hole-transporting substance according to claim 1, wherein the hole-transporting substance is (7) An electrophotographic photoreceptor comprising an organic photosensitive layer containing the hole transporting substance according to any one of claims 1 to 6.