JPH0419667A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To adequately maintain excellent mechanical strength and electrical characteristics over a long period of time by using a specific polycarbonate polymer as the binder resin of a photosensitive layer. CONSTITUTION:The polycarbonate polymer which has the repeating unit expressed by formula I and has the terminal groups expressed by formulas II to VI at the terminal of the polymerized chain is used as the binder resin of the charge transfer material of the photosensitive layer provided on a conductive substrate. In the formula I, R<1> and R<2> respectively independently denote a halogen atom, 1 to 6C alkyl group, etc.; k and j respectively independently denote 0 or 1 to 4 integer; X denotes single bond, -O-, -S-, -SO-, etc. In the formulas II to V, R<5> to R<8> respectively independently denote 6 to 30C alkyl group, etc.; Y1 and Y2 respectively independently single bond, -O-, -COO-, etc. The excellent mechanical strength and electrical characteristics are maintained over a long period of time in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more specifically, the present invention relates to an electrophotographic photoreceptor, which is easy to produce, has excellent mechanical strength such as surface hardness, and electrical properties,
Furthermore, the present invention relates to an electrophotographic photoreceptor having improved durability.

[Prior Art] Recent electrophotographic photoreceptors are laminated organic electrophotographic photoreceptors in which the photosensitive layer consists of at least two layers: a charge generation layer that generates charges upon exposure and a charge transport layer that transports charges. body (OPC) is becoming mainstream.

In this type of laminated organic electrophotographic photoreceptor, the binder resin of the charge transport layer contains 2.2% as a monomer.
Polycarbonate resins made from -bis(4-hydroxyphenyl)propane (bisphenol A), powder R, and p-tert-butylphenol (PTBP) as a terminator are widely used.

This polycarbonate resin made from bisphenol A and PTBP has good compatibility with charge transport materials, so it has good electrical properties when manufactured as an electrophotographic photoreceptor, and has relatively high mechanical strength. have.

However, it has become clear that when a charge transport layer is formed using a conventional polycarbonate resin made from the above-mentioned bisphenol A or the like as a binder resin, there are problems such as the following (1) and (2).

■When coating and forming a charge transport layer during the production of electrophotographic photoreceptors, depending on the solvent used, the coating solution often turns white (gels), making it difficult to form a homogeneous charge transport layer. Occur.

Furthermore, even if it is coated and formed on a diagonal surface, crystallization is likely to occur in the charge transport layer, and light attenuation is difficult to occur in this crystallized area, so the charge remains as a residual potential, which deteriorates image quality. It appears as a defect.

■Charge transport layers using conventional polycarbonate resins made from the above-mentioned bisphenol A, etc. have poor adhesion to the base, are easy to peel, and have insufficient surface hardness.
The drawback is that it wears out and its printing life is shortened. The base here usually refers to a charge generation layer, but when a charge transport layer and a charge generation layer are sequentially laminated on a conductor, such as in a positively charged electrophotographic photoreceptor, the base is a charge generation layer. It also serves as a base when a blocking layer or intermediate layer is provided between a conductor or charge generation layer and a charge transport layer for the purpose of improving electrophotographic properties.

It is believed that such problems arise because the degree of crystallinity of conventional polycarbonate resins made from bisphenol A or the like as raw materials is relatively high.

[Problem to be solved by the invention]

The present invention has been made in view of the above circumstances.

An object of the present invention is to solve the above-mentioned problems observed in the production of conventional electrophotographic photoreceptors using conventional polycarbonate resins made from bisphenol A or the like as the binder resin of the charge transport layer, and to provide an electrophotographic photoreceptor. It has the advantage that the coating solution does not whiten (gel) during the preparation, and it is possible to easily form a high-quality charge transport layer in which the occurrence of defects on images is sufficiently suppressed.
The object of the present invention is to provide an electrophotographic photoreceptor that is practically excellent and can maintain excellent mechanical strength (such as surface hardness) and electrical properties for a long period of time.

[Means for Solving] The present inventors have focused mainly on what kind of polycarbonate resin can be used as the binder resin of the charge transport layer to solve the above problems, and have developed various novel polycarbonate resins. We have conducted extensive research on resins.

As a result, the present inventors have easily solved the above-mentioned problems by producing an electrophotographic photoreceptor using a polycarbonate polymer having a specific structure and having a specific terminal group as the binder resin of the charge transport layer. Based on this knowledge, we have completed the present invention.

That is, the present invention provides an electrophotographic photoreceptor having a photosensitive layer provided on a conductive substrate, in which a binder resin of a charge transport substance of the photosensitive layer is expressed by the following formula 〇 [However, R1 and R1 in formula (I) R2 is each independently,
Halogen atom, alkyl group having 1 to 6 carbon atoms, 5 to 6 carbon atoms
7 cycloalkyl group or an aryl group having 6 to 12 carbon atoms, k and j are each independently 0 or an integer of 1 to 4, and X is a single bond, -o--s--5o -1-so
z--c- (where R3, R' and R4 each independently represent a hydrogen atom, a trifluoromethyl group, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms), ) or -(CH2)r- (where r is an integer from 2 to 10). ] It has a repeating unit (1) represented by the following general formula at the end of the polymer chain [However, R5 to RI in formulas (n) to [■] are each independently a group having 6 to 30 carbon atoms. represents an alkyl group or a phenyl group, and Yl and Yz each independently represent a single bond, -o--c
Indicates oo- or -C(CHs)z-. The present invention provides an electrophotographic photoreceptor characterized by using a polycarbonate polymer having a terminal group represented by the following.

In the formula (I) above, when any one or more of R1 and R2 is a halogen atom, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Among these halogen atoms, fluorine atoms and chlorine atoms are particularly preferred.

Any one or more of R1 and R1 has 1 carbon number
In the case of the alkyl group of 6 to 6, examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, 5ec-butyl group, te
rt-butyl group, pentyl group, various isopentyl groups, t
Examples include an ert-amyl group, a neopentyl group, a hexyl group, various isohexyl groups, a tert-hexyl group, and a neohexyl group. Among these alkyl groups, methyl groups, ethyl groups, etc. are generally preferred, and methyl groups are particularly preferred.

Any one or more of R1 and R2 has 5 or more carbon atoms
In the case of the cycloalkyl group of 7, examples of the cycloalkyl group include a cyclopentyl group, various methylcyclopentyl groups, cyclohexyl group, and various methylcyclohexyl groups. Among these cycloalkyl groups, a cyclohexyl group is particularly preferred.

Any one or more of R1 and R2 has 6 or more carbon atoms
In the case of 12 aryl groups, examples of the aryl group include phenyl group, 0-lm- or P-tolyl group, xylyl group, trimethylphenyl group, ethylphenyl group, diethylphenyl group, ethylmethylphenyl group, propylphenyl group. group, isopropylphenyl group, methylpropylphenyl group, methylisopropylphenyl group, butylphenyl group, isobutylphenyl group, 5ec-butylphenyl l, tert-butylphenyl group, methyl-ter
t-butylphenyl i, each 11 pentylphenyl group, various hexylphenyl groups, alkylphenyl groups such as cyclohexylphenyl group, various biphenyl groups such as 4-phenylphenyl group, 1-naphthyl group, 2-naphthyl group, Examples include various methylnaphthyl groups, various dimethylnaphthyl groups, various ethylnaphthyl groups, anthracen-1-yl groups, anthracen-2-yl groups, anthracen-9-yl groups, and various methylanthracen-9-yl groups. . Among these aryl groups, phenyl groups are particularly preferred.

k and j indicating the respective numbers of the substituents R1 and R2;
are each independently 0 or an integer of 1 to 4, with O or 1 being particularly preferred.

In the formula (1) above, X represents a single bond or the various divalent groups described above.

When X is 10(R3) (R')-, R3 in this group
and R4 each independently represent a hydrogen atom, a trifluoromethyl group, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and specific examples of these alkyl groups and aryl groups include can include the various alkyl groups and aryl groups listed above. Various C(11") (R')- having these various R3 and R4
Among them, as a particularly representative example, for example, -CH2-
-C(CF*)z--C(C)13)Z~ -CH(C
2H1)-1-C(Ph)z- (where ph represents a phenyl group.

Same below. ), -CPh(C)lz)-, and the like.

p is an integer of 10, preferably 4 or 5, particularly 5
is preferred.

When X is -(CHz)-, r in this group is an integer of 2 to 10, with 2 being particularly preferred.

X is a single bond or the various divalent groups mentioned above, and representative examples thereof include, for example, a single bond, -0-
-5--5Oz--C(CF3) 2- can be obtained, particularly preferably, for example, -C(CH3)
2--C(Ph)z-, etc. can be mentioned.

Specific examples and particularly preferred examples of the repeating unit represented by formula (1), that is, the repeating unit (1), are shown by the below-mentioned bisphenol compound corresponding to the monomer unit in this repeating unit.

The polycarbonate polymer according to the present invention may be a homopolymer consisting of one type of the various repeating units [summer], a copolymer consisting of two or more types, or a copolymer consisting of two or more types of repeating units [summer]. It may be a mixture or composition of. Additionally, these polycarbonate polymers are
The repeating unit (
It may contain repeating units other than 1).

One important point in the polycarbonate polymer according to the present invention is that the polycarbonate polymer has the formula (It), [■], [■] or (V ) has a terminal group represented by

Here, the terminal group represented by the formula CII) and the formula (
The terminal group represented by IV) is a repeating unit (1) represented by the above formula (1) at the terminal end of the polymer main chain.
is the terminal group bonded to the left side (i.e. -〇~) of
On the other hand, the terminal group represented by the formula (m) and the formula (
The terminal group represented by V) is located on its right side (i.e. ~CO
-) is the terminal group bonded to.

More specifically, an example of the structure including the terminal group of the polycarbonate polymer according to the present invention is shown by a general formula, for example: [However, Z in these formulas is the repeating unit [
1] is a group represented by the following formula, which is a unit in y+ and Y: each independently represent the same meaning as above.

] Various types of expressions can be mentioned.

Among these, especially - It is preferable to have a structure represented by the following.

The following formula (II), CI[[), (IV) and [v]
In each of the formulas, R5, Rh, R7 and R8 are each independently,
Represents an alkyl group or phenyl group having 6 to 30 carbon atoms,
This alkyl group can be selected from various alkyl groups having a linear, branched, or cyclic structure, and in consideration of this point, specifically, for example, various hexyl groups, various heptyl groups, various Octyl group, various nonyl groups, various decyl groups, various undecyl groups, various F-decyl groups,
Examples include various tridecyl groups, various tetradecyl groups, various pentadecyl groups, various hexadecyl groups, various octadecyl groups, and various icosyl groups.

Among these alkyl groups, those having about 6 to 18 carbon atoms are preferred, and those having about 6 to 12 carbon atoms are particularly preferred.

Yl in the following formula (IV) and Y2 in the following formula EV)
each independently represents a single bond, -coo--o- or -C(
CI Ri! - represents.

The polycarbonate polymer having the specific terminal group according to the present invention may have the same terminal group for the left and right terminal groups in the above sense, or only one of them may be the same, It may be a mixture of polymer molecules in which the other end group is different, or it may be a mixture of polymer molecules in which both terminal groups are different from each other. Note that this polycarbonate polymer may contain polymer molecules having other terminal groups having structures other than those described above, within a range that does not impede the purpose of the present invention.

The polycarbonate polymer used in the electrophotographic photoreceptor of the present invention has a concentration of 0.5 g/methylene chloride as a solvent.
It is preferable that the reduced viscosity [η, /C] of the solution of d1 at 20°C is in the range of 0.4 to 2.0 a/g.

This reduced viscosity [ηsp/C] is 0.4 dll/g
If it is less than 100%, it may not be possible to obtain sufficient properties as a binder resin for the photosensitive layer, and the photoreceptor may be worn due to insufficient mechanical strength, especially surface hardness, and a practically sufficient printing life may not be obtained. be. On the other hand, if it exceeds 2.0 d1/g, the viscosity of the solution increases, which may make it difficult to form a photosensitive layer by a solution coating method and thus make it difficult to manufacture an electrophotographic photoreceptor.

The polycarbonate polymer comprising repeating units having the specific structure and having terminal groups having the specific structure, which is used as a binder resin in the photosensitive layer of the electrophotographic photoreceptor of the present invention, is particularly suitable for the production method thereof. There is no restriction, and by using appropriate raw materials, it can be manufactured by applying various techniques such as known methods.

As a manufacturing method, the following method can be mentioned, for example, as a method that can be normally used suitably.

That is, the polycarbonate polymer has the following general formula [wherein R', R2, k, J and X each have the same meaning as above. ] A bisphenol compound and a carbonate-forming compound represented by the following general formula % formula % [3 The following general formula R"-Coχ1 [■] or the following general formula [However, R9 and in the formula [■] RIG in formula [■] each independently corresponds to R5 or R6, and ×1 in formula [■] represents a halogen atom.
11 corresponds to the above R7 or R6, and y corresponds to the above Y1 or Y.
! corresponds to ] It can be practically advantageously synthesized by reacting the terminal capping agent represented by the following under appropriate conditions and atmosphere.

The bisphenol compound has the repeating unit (1)
Since it corresponds to the monomer unit in - formula (
Specific examples and preferred examples of R1, R2, k, j and X in Vl) are as described above.

Specific examples of this bisphenol compound include R1, R
2. There are many different types depending on k, j and X,
Typical examples include bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,2-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)ethane, hydroxyphenyl)propane, 2.2-bis(3-methyl-4-hydroxyphenyl)butane, 2.2-bis(4-hydroxyphenyl)
Butane, 2.2-bis(4-hydroxyphenyl)octane, 4.4-bis(4-hydroxyphenyl)hebutane, 4,4'-dihydroxytetraphenylmethane, 1
．． 1-bis(4-hydroxyphenyl)-1-phenylethane, 1.1bis(4-hydroxyphenyl)-1-
Phenylmethane, bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfone, 11-bis(
4-hydroxyphenyl)cyclopenkune, 1.1-bis(4-hydroxyphenyl)cyclohexane, 2.2
-bis(3-methyl-4-hydroxyphenyl)propane, 2-(3-methyl-4-hydroxyphenyl)-2-
(4-hydroxyphenyl)-1-phenylethane, bis(3-methyl-4-hydroxyphenyl) sulfide, bis(3-methyl-4-hydroxyphenyl) sulfone, bis(3-methyl-4-hydroxyphenyl)methane , 1.1-bis(3-methyl4-hydroxyphenyl)cyclohexane, 44-dihydroxyphenylbiphenyl, 22bis(2-methyl-4-hydroxyphenyl)propane, 1.1-bis(2-butyl-4-hydroxy) -5-methylphenyl)butane, 1,1bis(2-t
ert-butyl-4-hydroxy-3-methylphenyl)
Ethane, 1. l-bis(2-tert-butyl-4-hydroxy-5-methylphenyl)propane, 1.1-bis(2-tert-butyl-4-hydroxy-5-methylphenyl)butane, 1. l-Bis(2-tert-butyl-4-hydroxy-5-methylphenyl)isobutane, 1.1-bis(2-tert-butyl4-hydroxy-5-methylphenyl)hebutane, 1.1-bis( 2
-tert-butyl-4-hydroxy-5-methylphenyl)-1-phenylmethane, 1,1-bis(2-te
rt-amyl-4-hydroxy-5-methylphenyl)
Butane, bis(3-chloro-4-hydroxyphenyl)
Methane, bis(3,5-dibromo-4-hydroxyphenyl)methane, 2,2-bis(3-chloro4-hydroxyphenyl)methane, 2,2-bis(3-chloro-4-
hydroxyphenyl)propane, 2,2-bis(3-fluoro-4-hydroxyphenyl)propane, 2,2-
Bis(3-furomo4-hydroxyphenyl)propane, 2.2bis(3,5-dichloro-4-hydroxyphenyl)propane, 2.2-bis(3,5-difluoro-
4-hydroxyphenyl)propane, 22-bis(3,
5-dichloro-4-hydroxyphenyl)propane, 2
．． 2-bis(3-bromo4-hydroxy-5-chlorophenyl)propane, 2,2-bis(3,5-dibromo-
4-hydroxyphenyl)propane, 2,2-bis(3
, 5dichloro-4-hydroxyphenyl)butane, 2゜2-bis(3,5-dibromo-4-hydroxyphenyl)butane, 1-phenyl-1,1-bis(3-fluoro-4-hydroxyphenyl)ethane , bis(3-fluoro-4-hydroxyphenyl)ether, 3.3'-difluoro-4,4'-dihydroxybiphenyl, 1.1
-bis(3cyclohexyl-4-hydroxyphenyl)
Cyclohexane, 22-bis(4-hydroxyphenyl)-hexafluoropropane, 2.2-bis(3-phenyl-4-hydroxyphenyl)propane, 1.1-bis(3-phenyl-4-hydroxyphenyl)cyclohexane , bis(3-phenyl-4-hydroxyphenyl)sulfone, and the like.

Among these, 2,2-bis(4-hydroxyphenyl)propane, 4,4'-dihydroxytetraphenylmethane, l-phenyl-11-bis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl) ) sulfone, 1,1-his(4-hydroxyphenyl)
Cyclohexane, 2.2-bis(3-methyl-4-hydroxyphenyl)propane, 1.1-bis(3-methyl4-hydroxyphenyl)cyclohexane, 44'-dihydroxybiphenyl, 2.2-bis(3-phenyl) −
Preferred are 4-hydroxyphenyl)propane and the like.

Note that these may be used alone or in combination of two or more as a mixture.

As the carbonate ester-forming compound, various compounds used in the field of ordinary polycarbonate production can be used. Typical examples include:
Examples include various carbonyl dihalides including phosgene, haloformates such as chloroformate compounds, and carbonate ester compounds. Among these, phosgene is particularly preferably used.

Various compounds can be used as the terminal end group represented by formula [■], but specific examples include various heptane compounds having a linear, branched, or alicyclic structure. Acids include octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, octadecanoic acid, and the like.

The end-stopping side represented by the above-mentioned formula [■] can include acid halides corresponding to the various carboxylic acids mentioned above. As the halogen atom for this acid halide (namely, the above-mentioned XI), the various halogen atoms mentioned above can be mentioned, but a chlorine atom is usually preferred.

Various monophenols can be used as the terminal end group represented by formula (IX), and specifically, for example, P-cumylphenol, m-cumylphenol, O-cumylphenol, etc. Phenol, P hexylphenol, m
-hexylphenol, 0-hexylphenol, P-
Hebutylphenol, m-hebutylphenol, 0-hebutylphenol, p-octylphenol, m-octylphenol, 0-octylphenol, p-nonylphenol, m-nonylphenol, O-nonylphenol, p-decylphenol, p-(2=methylnonyl)phenol , p-undecylphenol, P-dodecylphenol, p-(2-methyldodecylphenol,
p-pentadecylphenol, p-hexadecylphenol, p-octadecylphenol, m-octadecylphenol, p-octyloxyphenol, m-octyloxyphenol, P-nonyloxyphenol,
P-decyloxyphenol, p-dodecyloxyphenol, ρ-hexadecyloxyphenol, p-octadecyloxyphenol, p-octyloxycarbonylphenol, m-octyloxyphenol, p-nonyloxycarbonylphenol, p- Examples include decyloxycarbonylphenol, (decyl p-hydroxybenzoate), p-dodecyloxycarbonylphenol (dodecyl p-hydroxybenzoate), p-hexadecyloxycarbonylphenol, and p-octyloxycarbonylphenol.

Among these, p-cumylphenol, p-hexylphenol, p-hebutylphenol, p-octylphenol, p-nonylphenol, p-decyloxyphenol, p-dodecyloxycarbonylphenol and the like are particularly preferred.

In addition, various compounds as these terminal capping agents are 1
The species may be used alone, or two or more species may be used in combination, such as in a mixture.

That is, the polycarbonate polymer used in the photosensitive layer of the present invention contains one or two of the bisphenol compounds.
It can be suitably obtained by reacting one or more of the carbonate ester-forming compounds with one or more of the various terminal terminators.

There are no particular limitations on the method of this reaction (reaction atmosphere, conditions, reaction system, operating method, etc.), and generally any known method used in the production of polycarbonate may be used as appropriate. For example, it can be produced by a polycondensation reaction using carbonyl dihalides such as phosgene as a carbonate-forming compound, or it can be produced by a polymerization reaction by transesterification using carbonates such as alkyl carbonate esters. You can also do that,
Alternatively, it can also be manufactured by a combination of these.

Here, when using carbonyl dihalides such as phosgene or haloformates such as chloroformate as the carbonate-forming compound, this reaction is carried out in an appropriate solvent with an acid acceptor (for example, an alkali metal hydroxide or an alkali metal hydroxide). This can be carried out in the presence of a basic alkali metal compound such as a metal carbonate or an organic base).

Various types of alkali metal hydroxides and alkali metal carbonates can be used, but from an economical point of view, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, etc. are usually preferably used. Ru. These can usually be suitably used as an aqueous solution.

The proportion of the carbonate-forming compound to be used may be appropriately adjusted in consideration of the stoichiometric ratio of the reaction.

Furthermore, when using a gaseous carbonate ester-forming compound such as phosgene, a method of blowing it into the reaction system can be suitably employed.

The ratio of the acid acceptor to be used is similarly determined by the stoichiometric ratio of the reaction (
It may be determined as appropriate, taking into account the amount (equivalent amount). Specifically, when using carbonyl dihalide such as phosgene, 2 equivalents or a slightly excess amount of acid acceptor is used relative to the total number of moles of bisphenol compounds to be subjected to the reaction (usually 1 mole corresponds to 2 equivalents). It is preferable to use

As the solvent, various solvents such as those used in the production of known polycarbonate may be used alone or as a mixed solvent.

Typical examples include halogenated hydrocarbon solvents such as methylene chloride.

Adjustment of the molecular weight of the obtained polycarbonate polymer, in other words, adjustment of the reduced viscosity of the polymer [η, /C) to the above-mentioned preferred range, can also be carried out by controlling reaction conditions such as reaction temperature, etc., but usually, the above-mentioned This can be easily achieved by appropriately selecting the ratio of the bisphenol compound and the terminal capping agent used.

The usage ratio of the terminal capping agent cannot be uniformly determined because it varies depending on other conditions, but for boat fishing, it is usually IX per mole of the bisphenol compound used.
10-' to about 0.2 mol, preferably lXl0-' to
It is appropriate to set the amount within a range of about 0.1 mol.

In addition, when carrying out this reaction, other molecular weight regulators (
For example, the reaction rate and molecular weight may be adjusted by adding monophenols other than the terminal capping agent, crosslinking agents, etc.) or reaction accelerators (eg, alkylamines, etc.).

The reaction temperature is usually 0 to l50'C2, preferably 5
It is appropriate that the temperature is in the range of ~40°C.

The reaction pressure can be any of reduced pressure, normal pressure, and increased pressure, but usually normal pressure or about the autopressure of the reaction system can be suitably used. The reaction time is usually about 0.5 minutes to 10 hours, preferably about 1 minute to 2 hours. As for the reaction method,
Any of the continuous method, semi-continuous method, batch method, etc. can be adopted.

In the manner described above, the polycarbonate polymer used in the photosensitive layer of the electrophotographic photoreceptor of the present invention can be advantageously synthesized.

The obtained reaction product (crude product) can be subjected to various post-treatments such as known separation/purification methods and recovered as a polycarbonate polymer of desired purity (purification degree).

The polycarbonate polymer can be produced in a practically advantageous manner in the manner described above.

Next, the electrophotographic photoreceptor of the present invention will be explained.

The electrophotographic photoreceptor of the present invention is characterized in that the polycarbonate polymer is used as a binder resin in its photosensitive layer.

That is, the electrophotographic photoreceptor of the present invention can be produced using various known formats as long as a polycarbonate polymer consisting of the above-mentioned specific repeating units and having a specific terminal group is used as a binder resin for at least one photosensitive layer. Any type of electrophotographic photoreceptor may be used, including an organic electrophotographic photoreceptor (OPC) having at least one charge generation layer (CGL) and at least one charge transport layer (CTL). It is preferable. The specific polycarbonate polymer may be used in any part of the photosensitive layer, but is usually included in at least one charge transport layer (CTL).
It is used as a binder resin in the form of a dispersed and dissolved charge transport material.

In the case of a multilayer electrophotographic photoreceptor having two or more charge transport layers, it is preferable to use it for all of the charge transport layers.

In the electrophotographic photoreceptor of the present invention, the polycarbonate polymer having the specific structure may be used alone, or
Two or more types may be used in a composition or in combination independently. Further, if desired, a binder resin component such as a polymer component such as another polycarbonate may be contained within a range that does not impede the object of the present invention, or various additives such as an antioxidant may be contained. .

As the conductive substrate material used in the electrophotographic photoreceptor of the present invention, various known materials can be used. Specifically, for example, metals such as aluminum, brass, copper, nickel, and steel can be used. A plate or metal sheet, a blank sheet that has been made conductive by coating a conductive substance such as aluminum, nickel, chromium, palladium, graphite, etc. by vapor deposition, sputtering, coating, etc., or a glass or plastic plate. ,
A substrate made of cloth, paper, etc. that has been subjected to conductive treatment can be used.

The charge generation layer has at least a charge generation material, and the charge generation layer is obtained by forming a layer on the underlying substrate by binding the charge generation material using a binder resin. Various known methods can be used to form the charge generation layer, but usually, for example, a coating liquid in which a charge generation material is dispersed or dissolved together with a binder resin in an appropriate solvent is applied to a predetermined base. A method such as applying the coating onto a substrate and drying it can be suitably used.

As the charge generation material in the charge generation layer, various known materials can be used, and specifically,
For example, simple selenium such as amorphous selenium and trigonal selenium,
Selenium alloys such as selenium-tellurium, Ag3 S 83
various selenides or selenium-containing compositions such as zinc oxide, inorganic materials consisting of Group 1 and Group II elements such as Cd5-3e, oxide semiconductors such as titanium oxide, silicon materials such as amorphous silicon, etc. Examples include inorganic materials such as metal or metal-free phthalocyanine, cyanine, anthracene, pyrene, perylene, pyrylium salt, thiapyrilim salt, polyvinylcarbazole, and various organic materials such as squareium pigment.

Note that these may be used alone, or
They can also be used in combination by mixing two or more types.

The binder resin in the charge generation layer is not particularly limited, and various known ones can be used. Specifically, for example, polystyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl Thermoplastic resins such as acetal, alkyd resin, acrylic resin, polyacrylonitrile, polycarbonate, polyamide, polyketone, polyacrylamide, butyral resin, polyester, thermosetting resin such as polyurethane, epoxy resin, phenolic resin, etc. can be used. .

As the binder resin in the charge generation layer,
Polycarbonate polymers of the invention can also be used.

The charge transport layer is usually provided as a layer formed by binding a charge transport material with a binder resin on the base.

As a method for forming this charge transport layer, various methods such as known methods can be used, but usually, for example, a coating method in which the charge transport material is dispersed or dissolved in a suitable solvent together with the binder resin of the present invention is used. A method of applying a liquid onto a predetermined substrate and drying it can be suitably used.

As the charge transporting material in the charge transporting layer, any of conventionally used electron transporting substances and hole transporting substances can be used.

Specific examples of electron-transporting substances include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-)lietro-9-fluorenone, and 2,4,5,7-tetranitro-9-tetra. Fluorenone, 24. Examples include electron-withdrawing substances such as mar-trinitro-9-dicyanomethylenefluorenone, 2.4.5.7-titranitroxanthone, and 2.4.9-trinidrothioxanthone, and polymerized versions of these electron-withdrawing substances. Note that these may be used alone or in combination of two or more.

Examples of the hole transport substance include toren, N-ethylcarbazole, N-isopropylcarbazole, N-methyl-N-
Phenylhydrazino-3-methylidene-9-ethylcarbazole, N N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-10-ethylphenothiazine, N N-diphenylhydrazino Dino-3-methylidene-
10-Ethylphenoxazine, P-diethylaminobenzaldehyde-N, N-diphenylhydrazone, p-diethylaminobenzaldehyde-N-α-naphthyl-N
-Phenylhydrazone, p-pyrrolidinohenzaldehyde N, N-diphenylhydrazino, 1,3.3-trimethylindolenine-ω-aldehyde = N, N-diphenylhydrazone, p-diethylbenzaldehyde-3-
Hydrazones such as methylbenzthiapurinone-2-hydrazone, 2,5-bis(p-diethylaminophenyl)
-1,3,4-oxadiazole, 1-phenyl~3-
(P-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[quinolyl (2))
-3-(p-diethylaminostyryl) -5-(p-
diethylaminophenyl)pyrazoline, 1-[levigyl (2)]-3-(p-diethylaminostyryl)-5-
(p-diethylaminophenyl)pyrazoline, 1-[6
-Medoxypyridyl (2))-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)
Pyrazoline, 1-[pyridyl(5))-3-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)
))-3-(p-diethylaminostyryl)-5-(p
-diethylaminophenyl)pyrazoline, 1-(pyridyl(2))-3-(p-diethylaminostyryl)-4
-Methyl-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2))-3(α-methyl-
P-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-phenyl-3-(p-
diethylaminostyryl)-4-methyl-5-(p-diethylaminophenyl)hilazoline, 1-phenyl-3
(α-benzyl-P-diethylaminostyryl)-5(
P-diethylaminophenyl)pyrazoline, spiropyrazoline and other pyrazolines, 2-(p-stylaminostyryl)-δ-diethylaminobenzoxazole, 2
Oxazole compounds such as -(p-diethylaminophenyl)-4-(p-dimethylaminophenyl)-5-(2-10lophenyl)oxazole, 2-(P-diethylaminostyryl)-6-dinithylaminobenzothiazole, etc. thiazole compounds, triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)-phenylmethane, 1. 1-bis(4-N, N-
diethylamino-2-methylphenyl)hebutane, 1,
1.2. Polyarylamines such as 2-tetrakis(4-N,N-dimethylamine-2-methylphenyl)ethane, N,N diphenyl-N,N'-bis(methylphenyl)benzidine, N,N '-diphenyl-N, N
-bis(ethylphenyl)benzidine, N,N diphenyl-N N'-bis(propylphenyl)benzidine, N,N'-diphenyl-N.

N'-bis(butylphenyl)benzidine, NN'-diphenyl-N'-bis(isopropylphenyl)
Benzidine, N,N'-diphenyl-N,N'-bis(
Benzidine-based compounds such as 2nd-butylphenyl)benzidine, N,N'-diphenyl-N, N'-Heath (tertiary-butylphenyl)benzidine, N,N-cypheny-N7 N'-bis(chlorophenyl)benzidine, Triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, poly-9-vinylphenylanthracene,
Pyrene-formaldehyde resin, ethylcarbazole-
Formaldehyde resin etc. can be mentioned.

Note that these may be used alone, or
Two or more types may be mixed and used in combination.

Specific examples of the solvent used in forming the charge generation layer and the charge transport layer include Hensen, toluene,
Aromatic solvents such as xylene and chlorohenzene, ketones such as acetone, methyl ethyl ketone, and cyclohexanone,
Alcohols such as methanol, ethanol and isopropanol, esters such as ethyl acetate and ethyl cellosolve, halogenated hydrocarbons such as carbon tetrachloride, carbon tetrabromide, chloroform, dichloromethane and tetrachloroethane, ethers such as tetrahydrofuran and dioxane, dimethyl Formamide, dimethyl sulfoxide, diethyl formamide, etc. can be mentioned.

These solvents may be used alone, or two or more may be used in combination as a mixed solvent.

Coating of each layer can be performed using various coating devices such as those known in the art. Specifically, for example, an applicator,
This can be carried out using a spray coater, a bar coater, a dip coater, a roll coater, a doctor blade, or the like.

As described above, the electrophotographic photoreceptor of the present invention, which uses a specific polycarbonate polymer consisting of repeating units having the specific structure and having terminal groups having the specific structure as the binder resin of the photosensitive layer, has terminal groups. A conventionally commonly used polycarbonate resin manufactured using a conventionally commonly used compound such as PTBP as a raw material (terminal capper or molecular weight regulator) and bisphenol A etc. as a raw material is used as a photosensitive layer of a charge transport layer. There are no problems with conventional electrophotographic photoreceptors used as binder resins or during their production, and the coating solution does not whiten (gel) during the production of electrophotographic photoreceptors, resulting in no defects on images. It has the advantage of being able to easily form a high-quality charge transport layer in which the occurrence of It is a practically excellent electrophotographic photoreceptor that can maintain suitable characteristics, and can be advantageously used in various electrophotographic photoreceptor application fields.

(Examples) Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to these Examples, and various modifications and variations can be made without departing from the spirit of the present invention. Application is possible.

In the following, the electrophotographic characteristics were measured using an electrostatic charging tester (newly manufactured by Kawaguchi Electric Manufacturing Co., Ltd., EPA-8100) with a corona discharge of -6 kV, and the initial surface potential (■.)
The evaluation was made by measuring the residual potential (V+t) and half-reduction exposure amount (El/2) after light irradiation (10 Lux).

Example 1 2,2-bis(4-hydroxyphenyl)propane 58.4 g (0,256 mol) as raw material monomer, concentration 8
% aqueous sodium hydroxide solution 550-1 methylene chloride 4
00 paper, 0.8 g of p-nonylphenol as a terminal stopper (molecular weight regulator), and 10% triethylamine aqueous solution 3j11 as a catalyst! into a reactor with a baffle plate,
While maintaining the temperature of the reaction solution at around 10° C. and stirring vigorously, phosgene gas was blown into the solution to carry out the polycondensation reaction.

After the reaction is complete, methylene chloride II is added to the organic phase. The mixture was diluted with , washed with water, diluted hydrochloric acid, and water in this order, and then poured into methanol to obtain a polycarbonate polymer.

This polymer has a concentration of 0.5 g using methylene chloride as a solvent.
The reduced viscosity of the solution of /a at a temperature of 20°C [η, p/
C) was 0.86 d/g.

In addition, the structure and composition of the above-obtained polymer are expressed as H-NM
When analyzed by R spectrum, phenyl group (6,
7-7. Absorption of the methylene chain (1.3 ppm) of the nonyl group at the end of the molecule was observed, and it was confirmed that this polymer had the following repeating unit and terminal structure.

A 10% by weight tetrahydrofuran solution of the above polycarbonate containing 50% by weight of the following hydrazone compound as a charge transport material was prepared. Even when this coating liquid was allowed to stand for one month, no clouding, gel formation, etc. were observed. Using aluminum as the conductive substrate, this coating solution was applied by dip coating onto a charge generation layer of approximately 0.5 μm using oxotitanium phthalocyanine, and after drying, a charge transport layer of 20 μm was provided to form a laminated electrophotographic photosensitive layer. The body was created.

The charge transport layer did not crystallize during coating.

The results of electrophotographic properties are shown in Table 1. The surface hardness (pencil hardness: JIS K-8400) of this charge transport layer was B.

Example 2 65.5 g (0,256 mol) of 2,2-bis(3-methyl-4-hydroxyphenyl)propane as monomer
A polymer ([η, , /C) = 0.78 di/g) was obtained in the same manner as in Example 1, except that 1.1 g of p-hydroxybenzoic acid-n-dodecyl was used as the terminal capping agent. Also, from 'H-NMR spectrum analysis, it was recognized to have the following repeating unit and terminal structure.

Using this polymer, a laminated electrophotographic photoreceptor was produced in the same manner as in Example 1. The evaluation results regarding stability of the coating liquid, crystallization during coating, electrophotographic properties (Table 1), and surface hardness were all the same as in Example 1.

Example 3 70 g (0.2 mol) of 4,4'-dihydroxytetraphenylmethane and 13 g (0,057 mol) of 2,2-bis(4-hydroxyphenyl)propane were used as 7-mers.
p-F decyloxyphenol 1.0 as terminal capping agent
Polymer (C7/
, , IC]=0.92 di/g). Also, 'H
- From NMR spectrum analysis, it was recognized to have the following repeating unit and terminal structure.

A laminated electrophotographic photoreceptor was produced in the same manner as in Example 1 using Copolymer No. 20. The evaluation results regarding stability of the coating liquid, crystallization during coating, electrophotographic properties (Table 1), and surface hardness were all the same as in Example 1.

Comparative Example 1 Polycarbonate ((η□/C)=0.78 di/ g), an attempt was made to produce a laminated electrophotographic photoreceptor in the same manner as in Example 1. As a result, the coating solution became cloudy on the second day and a gel was generated. Further, a portion of the charge transport layer during coating was crystallized (whitened).

Further, the surface hardness of this charge transport layer was 4B.

The electrophotographic properties were as shown in Table 1.

(Margin below) Table 1 Electrophotographic properties [Effects of the invention] According to the present invention, a specific polycarbonate polymer consisting of repeating units with a specific structure and having end groups with a specific structure is used as the binder resin of the photosensitive layer. Conventional polycarbonate resins manufactured using bisphenol A and the like as raw material monomers are used as binder resins for the photosensitive layer. The above-mentioned problems observed in the electrophotographic photoreceptor and its production have been fully resolved, and the coating solution does not whiten (gel) during the production of the electrophotographic photoreceptor, and defects on images are prevented. It has the advantage of being able to easily form a high-quality charge transport layer that is sufficiently suppressed, and maintains excellent mechanical strength (especially surface hardness, stiffness resistance, etc.) and electrical properties over a long period of time. It is possible to provide an electrophotographic photoreceptor that is practically excellent in that it can be maintained.

Claims (1)

[Claims] 1. In an electrophotographic photoreceptor in which a photosensitive layer is provided on a conductive substrate, the binder resin of the charge transport substance of the photosensitive layer includes the following general formula ▲ mathematical formula, chemical formula, table, etc. ▼ ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] [However, R^1 and R^2 in formula [I] each independently represent a halogen atom, an alkyl group having 1 to 6 carbon atoms, or a 5-carbon atom. -7 cycloalkyl group or C6-12 aryl group, k and j are each independently 0 or 1-4
is an integer, and X is a single bond, -O-, -S-, -SO
−, −SO_2−▲There are mathematical formulas, chemical formulas, tables, etc.▼(
Here, R^3 and R^4 are each independently a hydrogen atom,
trifluoromethyl group, alkyl group having 1 to 6 carbon atoms, or aryl group having 6 to 12 carbon atoms), ▲numerical formulas, chemical formulas, tables, etc.▼(here, p is 4 to 12)
Indicates an integer of 10. ) or -(CH_2)_r- (where r is 2~
It is an integer of 10. ) is shown. ] It has a repeating unit [I] represented by the following general formula at the end of the polymer chain ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [II], ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [III], ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [IV] or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [V] [However, R^5 to R^6 in formulas [II] to [V] are respectively Each independently represents an alkyl group or phenyl group having 6 to 30 carbon atoms, and Y^1 and Y^2 each independently represent a single bond, -
Indicates O-, -COO- or -C(CH_3)_2-. ] An electrophotographic photoreceptor characterized by using a polycarbonate polymer having a terminal group represented by the following.