JPH07219247A - Monolayer electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To enable a photoreceptor to be excellent in electrification property, high in sensitivity and high in transfer potential of a latent image by using a polymer material showing ferroelectric property as the binder. CONSTITUTION:A monolayer org. photoreceptor is formed directly on a conductive base body or through a base coating layer. The photosensitive layer contains dispersion of granular charge producing material and org. hole transfer material in a binder comprising a ferroelectric polymer. The photoreceptor consists of a conductive base body 1, photosensitive layer 2, charge producing pigment 21, and org. hole transfer material 22 dispersed in a molecular state in a binder 23. The binder 23 gives not only good dispersion of the charge producing material and the transfer material in a molecular state, but also an effect to improve the electrostatic transfer property of the photoreceptor required for the latent image transfer process. When the photoreceptor is electrified, the inner polarity generating in the resin film increase the change transfer performance of the charge producing material 21 and the org. hole transfer material, which gives good results to the electrostatic transfer process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electrophotographic photosensitive member, and more particularly to an electrophotographic photosensitive member that can be used in an electrophotographic copying machine or a printer.

[0002]

2. Description of the Related Art Conventionally, inorganic compounds such as selenium, selenium-tellurium alloys, selenium arsenide, and cadmium sulfide have been used as photoreceptors used in electrophotographic processes.
However, these materials have drawbacks that they are highly toxic, they are difficult to handle because they are used in an amorphous state, and they require high-cost production because they need to be vacuum-deposited to a thickness of several tens of μm. . Organic photoreceptors are attracting attention because they are less toxic, lighter, more flexible, and more productive than inorganic photoreceptors. Photoreceptor (OPC)
Has been actively developed and has come to be partially put into practical use. Most of these photoreceptors have a laminated structure in which a layer having a charge generating function (CGL) and a layer having a charge transporting function (CTL) are functionally separated, and are mainly used in a negative charging process. There is. This is because the charge generation material, the hole transfer material, the acceptor material, and the like are dispersed and mixed in the same film in a so-called single-layer structure photoreceptor,
While various characteristics such as sensitivity and electrostatic properties tend to be lowered to practical levels or less due to fatigue phenomena, the laminated-type photoconductor can suppress these defects as much as possible. CT with high dynamic strength and thick film design
By disposing L on the surface of the photoconductor, it becomes possible to maintain sufficient durability on the photoconductor when it is subjected to the process. However, since the organic materials exhibiting a high charge mobility that does not hinder the high speed process are limited to the donor compounds having the property of hole transfer at present, they are formed by the donor compounds. In the photoconductor having the CTL on the surface side, the charging polarity is negative.

However, a new problem has arisen in such a function-separated laminated structure. The first is derived from the negative charging of the photoconductor. Generally, in the electrophotographic process, a corona discharge method is adopted as a highly reliable charging method, but as is well known, the corona discharge is more unstable in the negative polarity than in the positive polarity. Although it must be adopted, the cost of parts is higher than that of the corotron, which is one of the reasons for the cost increase. Secondly, since the negative corona discharge is accompanied by more generation of ozone, the ozone filter is adopted for the purpose of preventing the outflow of ozone, but this is also directly related to the cost increase. In addition, two-component toners that are widely used at present are more stable against environmental fluctuations when the photoconductor polarity is positively charged, and the positive charging method is also preferable for these additions. The third is derived from the laminated structure of the photoconductor. That is, in order to manufacture a laminated type photoreceptor,
It is necessary to apply at least two steps or more, but in order to obtain a good image while maintaining the balance of sensitivity and durability, the film thickness of CGL must be controlled in the submicron order, which is a factor of increasing the manufacturing cost. Has become.

Therefore, in recent years, a single-layer photosensitive member has been reviewed to counter the above-mentioned function-separated laminated photosensitive member. For example, Japanese Patent Publication No. 34-10966 discloses poly-N-vinylcarbazole and 2, A charge transfer complex type single-layer photosensitive material containing 4,7-trinitro-9-fluorenone has been proposed, and is disclosed in Japanese Patent Publication Nos. 48-25658 and 4-4.
No. 8-38430 discloses a pyrylium dye and poly-N.
A eutectic complex-type single-layer photoconductor comprising vinylcarbazole has been proposed. Further, in JP-A-54-1633, a single-layer photoreceptor in which a charge-generating pigment is dispersed in a resin together with a donor and an acceptor which are charge-transporting substances is further disclosed in JP-A-3-1633.
2556050 proposes a single-layer photoreceptor having the same structure as described above using a diphenoquinone derivative as an acceptor. However, all of these photoreceptors
It is inferior in terms of photosensitivity and durability, and many of the laminated type photoreceptors that have been put into practical use are simply dispersed, and in addition to sensitivity, there are many inferior electrification properties, durability, etc. It wasn't possible.

On the other hand, the latent image transfer system, which is one of the electrophotographic systems, differs from the above-mentioned Carlson method in that a voltage is applied between the photoconductor and an electrostatic recording medium capable of holding an electrostatic latent image. In this way, the electrostatic latent image formed on the photoconductor is transferred onto the electrostatic recording body, and then the transferred electrostatic latent image is developed and visualized. This method has been known for a long time. M. Schafert's "Electronic Photography" (Kyoritsu Publishing, 1973), TESI (Latent Image Transfer) on page 70
There is a description of the law. According to it, in the latent image transfer method, a sequential method in which an electrostatic latent image is first formed on a photoconductor and then the electrostatic image is transferred to the electrostatic recording body, and an electrostatic recording body and a photoconductor are used. There is a direct method of making electrostatic production in contact.

The latent image transfer method has a drawback that plain paper cannot be used because it requires a conductive layer and a dielectric layer as a recording medium as compared with the Carlson method, but the electrostatic latent image on the photoconductor is directly developed. Since it is not necessary, there is a merit that there is a high margin in the device design in which various units necessary for the electrophotographic process are arranged around the electrophotographic photosensitive member. Taking advantage of such merits, a copying machine employing a sequential latent image transfer method was commercially available in the early days of the electrophotographic apparatus. As an electrophotographic photosensitive member used in such a copying machine, vapor deposition Se is used.
There is a laminated type photoreceptor in which a layer is used as a charge generation layer and polyvinylcarbazole is used as a charge transport layer. However, a photoconductor that can be applied to a copying machine using such a sequential transfer system does not need to have special characteristics, and the electrophotographic photoconductor for the Carlson method can be used as it is for the latent image transfer process of the sequential transfer system. It can be used as a photoconductor for use. On the other hand, in the simultaneous transfer method, a device for the photoconductor is required to be more effective than the sequential transfer, and therefore, for example, JP-A-56-436.
No. 65 proposes to provide an insulating layer to meet the demand for high breakdown voltage.

However, recently, instead of competing with the Carlson method within the range of application of the Carlson method, the latent image transfer method is reviewed and examined for high quality electrophotographic image output which is difficult with the Carlson method. Has been done. This is because the latent image transfer method does not require a transfer step after development, and thus has a possibility of obtaining an essentially high-definition and high-quality image as compared with the Carlson method.

As a photoreceptor for a latent image transfer system used in such a high-quality image output device, sensitivity is high and stability of potential due to repetition is an important factor. Above all, it is necessary that the transfer potential be high. There is. If the transfer potential is low, the density of the output image will be low. To increase the transfer potential,
A transfer voltage may be applied so as to increase the difference between the potential of the photoconductor and the potential of the conductive layer of the recording medium at the time of latent image transfer, but if the transfer voltage is set too high, an abnormal image such as image loss may occur. Occurs. Further, if the dielectric layer of the recording material is thickened, the electric potential of the recording material is improved, but even in this case, the transferred charge amount does not increase. It is understood that in a system in which the process speed is slowed down to improve the image quality, the development density is mainly determined by the surface charge amount of the recording material, and thus such a measure cannot increase the image density.

In view of the above problems, it is understood that an electrophotographic photosensitive member which can secure a high transfer potential of the electrostatic recording material is desired for the high quality latent image transfer process. However, it has been unclear whether a high transfer potential can be obtained immediately when a conventionally used electrophotographic photoreceptor is used in a latent image transfer process. In fact, when the multi-layer type photoconductor was applied to the process, the transfer potential was rather low.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photosensitive member for transferring a latent image, which is excellent in charging property and sensitivity and has a high latent image transfer potential.

[0011]

The inventors of the present invention have made various studies on a single-layer type organic electrophotographic photosensitive member which is suitable for positive charging property or both positive and negative charging properties. It has been found that a desirable electrophotographic photoreceptor can be obtained by using a polymer having ferroelectricity as a component and a charge generating substance, an organic hole transfer substance and an organic acceptor compound together with the binder.
Furthermore, the present inventors have found that the present electrophotographic photosensitive member exhibits a good effect not only in the conventional Carlson process but also in the electrostatic latent image transfer process, and completed the present invention.

That is, according to the present invention, after the electrostatic latent image is formed on the electrophotographic photosensitive member, the electrostatic recording member is brought into contact with the surface side of the photosensitive member so as to contact the photosensitive member and the electrostatic recording member. A latent image transfer type electrophotography in which a voltage is applied between the two to transfer an electrostatic latent image corresponding to the photoconductor onto the electrostatic recording body, and then the electrostatic latent image on the electrostatic recording body is visualized. In the electrophotographic photoreceptor used in the method, a single-layer organic photoreceptor is provided on a conductive substrate directly or via an undercoat layer, and the photosensitive layer is at least in a particulate form, and a charge generating substance and an organic hole transporting material are formed. The substance is dispersed in a binder composed of a ferroelectric polymer, and as the organic hole transporting substance, compounds represented by the following general formulas (4) to (10) are preferably used. The electrophotographic photoreceptor, and the weight composition ratio to the organic hole transporting material is 1/5 to 50. 1, preferably electrophotographic photoreceptor characterized in that the organic acceptor compound is between 1 / 5-5 / 1 is added is provided.

The photoreceptor of the present invention is typically shown in FIG.
It has the configuration shown in. Reference numeral 1 is a conductive substrate, 2 is a photosensitive layer, 21 is a charge generating pigment, and 22 is an organic hole transporting substance molecularly dispersed in a binder 23. See also FIG.
(B) represents another photoreceptor of the present invention to which the organic acceptor compound 24 dispersed in a molecular form is added. The role of the binder in the present invention is not only good dispersion of the charge generating substance and molecular dispersion of the transporting substance, but also improving the electrostatic transfer ability of the photoreceptor required in the latent image transfer process. I am also responsible. However, at present, it is not completely understood whether good results are obtained when a polymer having ferroelectricity is used as a binder, but the internal polarization generated in the resin film when charged is due to charge Source,
It is presumed that the charge transporting ability of the organic hole transporting material is enhanced, and that this electrostatic transfer process gives good results. The amount of these ferroelectric binders occupying the entire photosensitive layer is preferably 20 to 90 wt% in terms of the amount of other additives, and preferably 30 to 70 wt%. The photosensitive layer of the present invention has a thickness of 5 to
30 μm is preferable. If it is thinner than this, the chargeability will decrease,
If it is thick, the electrostatic capacity of the photoconductor is reduced, and the transfer potential is reduced. Specific examples of the amount of the ferroelectric polymer agent that can be used in the present invention are as follows.

[Fluorine Resin Represented by Polyvinylidene Fluoride] Specifically, polyvinylidene fluoride (PVD)
F), vinylidene fluoride-trifluoroethylene copolymer [P (VDF / TrFE)], vinylidene fluoride-tetrafluoroethylene copolymer [P (VDF / TeFE)], vinylidene fluoride-vinyl fluoride Copolymer [P (VDF /
VF)], vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene ternary copolymer [P (VDF / TeFE
/ HFP)], vinylidene fluoride-pa-fluoroacetone copolymer [P (VDF / PFA)] and the like. Among them, from the viewpoint of ferroelectric properties and solubility in organic solvents, [P (VDF / TrFE)], [P (VDF /
PFA)], [P (VDF / TeFE)] and the like are preferable.

[Nylon-based ferroelectric polymer having the following repeating unit (1)]

[Chemical 1] (Here, m and n are 1, 3, 5, 7, and 9, and x represents the degree of polymerization.) [Urethane-based ferroelectric polymer having the following repeating unit (2)]

[Chemical 2] (Here, m is 6, 7 and n is 3, 5 and x represents the degree of polymerization.) [Thiourea-based ferroelectric polymer having the following repeating unit (3)]

[Chemical 3] (Here, m is 5, 7, and 9, and x represents the degree of polymerization.)

Next, the inventors of the present invention are concerned with the hole transport material.
Even if it is used, it is necessary to consider it, especially assuming that it will be used with positive charging.
Then, the generated holes are dispersed in the hole transport material in a molecular form.
Matrix Highly injected and highly movable
A material having a high hole mobility was selected. Preferred in the present invention
The hole transporting substances that are commonly used include
Examples are shown by the formulas (4) to (10). (In the formula, Ar₁, Ar₂And Ar₃Is an unsubstituted or
Alkyl group, alkoxy group, thioalkoxy group, aryl
Oxy group, halogen atom, cyano group, nitro group or
Represents an aryl group substituted with an amino group or a heterocyclic group
You )

[Chemical 4](In the formula, R₁And R₂Is a hydrogen atom, an alkyl group or aryl
Represents a R group, and R₁, R₂You may form a ring between
Yes. Ar₁Represents an arylene group or a heterocyclic group. Ar₂
And Ar₃Is an alkyl group, an aryl group, or a heterocyclic group
Represent ) (In the formula, Ar₁, Ar₂And Ar₃Is unsubstituted or
Alkyl group, alkoxy group, halogen atom, cyano group,
An aryl group substituted with a nitro group or an amino group, or
Represents a heterocyclic group. )

[Chemical 5] (In the formula, Ar ₁ , Ar ₂ , Ar ₅ and Ar ₆ represent an aryl group which is unsubstituted or substituted with an alkyl group, an alkoxy group, a halogen atom, a cyano group, a nitro group or an amino group, and Ar ₃ and Ar ₄ represents an unsubstituted arylene group or an arylene group substituted with the above substituents.)

[Chemical 6](In the formula, Ar₁, Ar₂, Ar₃And Ar_FourIs the
Or alkyl group, alkoxy group, halogen atom, cyano
Aryl groups substituted with groups, nitro groups or amino groups
X is an alkylene group, sulfur, oxygen or (CH = C
H)_n(N is an integer of 1 or more). ) (In the formula, Ar₁Is an unsubstituted or alkyl group,
Xy group, halogen atom, cyano group, nitro group or
Represents an aryl group or a heterocyclic group substituted with a mino group,
r₂And Ar₃Is an alkyl group, phenyl group or naphthyl group
Represents )

[Chemical 7] (In the formula, Ar ₁ , Ar ₂ , Ar ₃ and Ar _{4 each} represent an unsubstituted or alkyl group, an alkoxy group, an aryl group substituted with a halogen atom or an amino group, or a heterocyclic group. It represents an integer of 0 or 1.) Specific examples thereof are shown in Table 1.

[0017]

[Table 1- (1)]

[0018]

[Table 1- (2)]

[0019]

[Table 1- (3)]

[0020]

[Table 2- (1)]

[0021]

[Table 2- (2)]

[0022]

[Table 2- (3)]

[0023]

[Table 3- (1)]

[0024]

[Table 3- (2)]

[0025]

[Table 4- (1)]

[0026]

[Table 4- (2)]

[0027]

[Table 5- (1)]

[0028]

[Table 5- (2)]

[0029]

[Table 5- (3)]

[0030]

[Table 6- (1)]

[0031]

[Table 6- (2)]

[0032]

[Table 6- (3)]

[0033]

[Table 6- (4)]

[0034]

[Table 7- (1)]

FIG. 2 shows the transfer of an electrostatic latent image in the sequential transfer system. In the figure, 3 is an electrostatic recording medium, 31 is a dielectric layer of the electrostatic recording medium, 32 is a conductive layer of the electrostatic recording medium, 4 is a conductive roller, and 5 is an applied voltage at the time of transfer. By setting the applied voltage value, it is possible to select a mode in which the charged portion of the photosensitive member is transferred (positive transfer) and a mode in which the non-charged portion or the low charged portion of the photosensitive member is transferred (negative transfer).

Such a photoreceptor of the present invention is excellent in charging property and sensitivity, and when used in a sequential transfer process, the transfer potential of the recording medium is set to a sufficient developing density under a transfer condition in which an abnormal image such as a blank area does not appear. Can be as high as possible. The reason for this is not clear at present, and further investigation is required in the future, but it is presumed that high chargeability and high sensitivity also lead to a high transfer potential for the following reasons.

In order to improve the image quality, it is necessary to carry out each process up to the visualization under mild conditions, resulting in a slow process speed. In such a case, it takes a lot of time from charging to transfer. When a photoconductor having poor charging property is used, the dark decay rate is high, so the potential contrast between the image area and the non-image area is reduced, and the potential contrast on the electrostatic recording material after transfer is also reduced. .

Further, the excellent sensitivity leads to a large potential contrast on the photoconductor and a high potential contrast on the electrostatic recording medium. When used with positive charge, the main cause of dark decay is electron injection from the substrate, but the photoconductor used with this charge polarity has a far superior hole transfer function, and electron injection from the substrate is low. Therefore, the charging property is secured. The hole transfer material used in the present invention is particularly excellent in high hole mobility. Further, an advantage of using the organic acceptor compound is that both positive and negative charge polarities can be dealt with by changing the composition of the hole transport material and the organic acceptor compound. The use of organic acceptor compounds also leads to a lower residual potential and a longer life of the electrostatic properties of the photoreceptor. The cause of these improvements is not clear, but one of them is to prevent the reduction of the internal electric field of the charge generation pigment and the reduction of the electric resistance by extracting the electrons out of the holes and electrons generated in the charge generation pigment by light irradiation. Can be considered.

The composition of the charge generating substance used in the present invention is 0.1 to 40 wt%, preferably 0.3 to 25 wt%. The composition of the hole transport material used in the present invention is 1
0 to 80% by weight, preferably 20 to 50% by weight is suitable.

The charge generating substance that can be used in the present invention is, for example, an X type metal-free phthalocyanine,
π-type metal-free phthalocyanine, τ-type metal-free phthalocyanine, ε-type copper phthalocyanine, α-type titanyl phthalocyanine, β-type titanyl phthalocyanine and other phthalocyanine pigments and disazo trisazo pigments, anthraquinone pigments, polycyclic quinone pigments, Indigo pigment, diphenylmethane, trimethylmethane pigment, cyanine pigment, quinoline pigment, benzophenone, naphthoquinone pigment,
Perylene pigments, fluorenone pigments, squarylium pigments, azurenium pigments, perinone pigments, quinacridone pigments, naphthalocyanine pigments, and porphyrin pigments can be used. Examples of the organic acceptor compound that can be used in the present invention include quinone compounds, π-electron compounds having a nitrile group, and π-electron compounds having a nitro group. When an organic acceptor compound is used, the amount ratio of the hole transport material and the organic acceptor compound is 1
/ 5 to 50/1, preferably 1/5 to 5/1. When the amount of the hole transport material is less than this, the repetition of electrostatic characteristics is deteriorated. As the conductive substrate that can be used in the present invention, aluminum, nickel, copper, a metal plate such as stainless steel, a metal drum or metal foil, aluminum,
Examples thereof include a plastic film coated with a thin film of tin oxide or copper iodide, or glass.

In the photoreceptor of the present invention, an undercoat layer may be provided between the photosensitive layer and the conductive substrate for the purpose of improving the charging property. As these materials, in addition to the binder material, polyamide resin, polyvinyl alcohol, casein, polyvinylpyrrolidone or the like can be used. In order to produce the photoreceptor of the present invention, a photosensitive layer forming liquid prepared by dissolving or dispersing the above materials in an organic solvent by a ball mill, ultrasonic waves or the like is applied onto a substrate by a dipping method, blade coating, spray coating or the like. It may be applied to form a photosensitive layer.

[0042]

EXAMPLES The present invention will be described below with reference to examples, but the embodiments of the present invention are not limited thereby.

Example 1 1 g of a bisazo pigment represented by the following structural formula was added to P (VDF /
TrFE) solution was ball-milled with 10 g (copolymerization ratio = 65/35: 10 wt% dissolved in tetrahydrofuran) and 9 g of tetrahydrofuran, and then 10 wt% pigment composition, 50 wt% PC-Z composition, hole transport material. 15D so that (D2-12) is 40wt%
% PC-Z solution, an acceptor compound, and a hole transport material were added to prepare a photoreceptor coating solution. This solution was applied on an aluminum substrate and dried by heating to prepare a single-layer type photoreceptor having a thickness of about 12 μm. This photoconductor was charged with a charging potential Vs (20 after the start of charging by an electrostatic copying paper tester (SP-428) manufactured by Kawaguchi Electric Co., Ltd.
The surface potential value after seconds and the exposure amount (E1 / 2) required for the surface potential after irradiation with light to be attenuated to 1/2 were measured. The results shown in Table 8 were obtained.

[Chemical 8]

Example 2 A photosensitive layer was prepared and electrostatic properties were measured in the same manner as in Example 1 except that the fluorocarbon resin shown below was used instead of the strong induction binder. The results shown in Table 8 were obtained.

[Chemical 9]

Example 3 A photosensitive layer was prepared and transfer characteristics were measured in the same manner as in Example 1 except that the polyamide resin shown below was used in place of the strong induction binder of Example 1. The results shown in Table 8 were obtained.

[Chemical 10]

Example 4 A photosensitive layer was prepared and transfer characteristics were measured in the same manner as in Example 1 except that the polyamide resin shown below was used in place of the strong induction binder of Example 1. The results shown in Table 8 were obtained.

[Chemical 11]

Example 5 A photosensitive layer was prepared and transfer characteristics were measured in the same manner as in Example 1 except that the polyamide resin shown below was used in place of the strong induction binder of Example 1. The results shown in Table 8 were obtained.

[Chemical 12]

Example 6 A photosensitive layer was prepared and the transfer characteristics were measured in the same manner as in Example 1 except that the polyamide resin shown below was used instead of the strong induction binder of Example 1. The results shown in Table 8 were obtained.

[Chemical 13]

Example 7 A photosensitive layer was prepared and the transfer characteristics were measured in the same manner as in Example 1 except that the thiourea-based resin described below was used instead of the strongly inductive binder in Example 1. The results shown in Table 8 were obtained.

[Chemical 14]

[Table 8]

Example 8 The photoreceptor used in Example 1 was corona-charged at +6.5 KV in the dark, and when the surface potential after dark decay reached 600 V, 30 lux of tungsten light was irradiated for 1 second. After the light irradiation, the electrostatic recording paper was brought close to the surface of the photoconductor, and the transfer paper was separated while being pressed against the surface of the photoconductor by the conductive roller.
At this time, a voltage was applied to the conductive roller so that the potential difference from the potential on the exposed portion of the photoconductor was + 800V. When the surface potential on the electrostatic recording paper was measured, -130V was obtained. Due to the electrostatic capacity of the electrostatic recording paper, this potential has a surface charge density of 8.7.
It was found that the surface charge density reached a level corresponding to × 10 ^-8 C / cm ^{2, which} was sufficient for development. When the transfer potential was measured on the unexposed portion under the same conditions, the transfer potential was 0V.

Examples 9 to 14 Using the photoconductors used in Examples 2 to 7 respectively, Example 8
By the same method as described in (1), electrostatic recording was performed and the transfer characteristics were measured. The results shown in Table 9 were obtained.

[Table 9]

Examples 15 to 19 The hole transporting material of Example 1 was replaced with the one shown in Table 10, and the following acceptor compound was further added, and the pigment composition was 4%, the resin composition was 50%, and the hole transfer material composition was 30. %, And the acceptor compound composition was 16% to prepare a photosensitive layer. Then, when the transfer characteristics were measured in the same manner as in Example 1, it was 0 in the unexposed area.
The results shown in Table 10 were obtained for the V and exposed areas.

[Chemical 15]

[Table 10]

Examples 22 to 23 Photosensitive layers were prepared in the same manner as in Example 8 except that the pigments of Example 8 were replaced by the following, and the transfer characteristics were measured.
The result was obtained.

[Chemical 16]

[Table 11]

Example 24 A photosensitive layer was prepared by substituting the following compounds for the acceptor compound of Example 8 and further using a pigment composition of 2%, a resin composition of 50%, a hole transfer material composition of 8% and an acceptor compound composition of 40%. . Corona charging was performed at -6 KV, and when the charging potential became -600 V, exposure was performed in the same manner as in Example 1. Then, a voltage was applied to the conductive roller to transfer the electric charge to the electrostatic recording paper in the same manner as in Example 1. A voltage was applied to the conductive roller so that the difference from the charged portion of the photoconductor was + 800V. In the unexposed area-
A result of 145V and 0V at the exposed portion was obtained.

[Chemical 17]

Comparative Example 1 The binder of Example 1 was replaced with polycarbonate (PC-Z) which did not exhibit ferroelectricity, and the electrostatic properties were evaluated in the same manner as in Example 1. The results shown in Table 8 were obtained. was gotten. Further, using this photoreceptor, the transfer characteristics were evaluated by the same method as in Example 8. As a result, the unexposed portion was -0 V and the exposed portion was -110 V.
The transfer potential of was obtained.

Comparative Example 2 When the hole transporting material of Example 1 was charged as in Example 1, charging was carried out in the same manner as in Example 1. However, the dark decay was too large, and the transfer was −40 V in the unexposed area and −120 V in the exposed area. A potential was obtained.

[Chemical 18]

Comparative Example 3 A charge generation layer comprising the azo pigment used in Example 1 and a resin (1/1 in weight ratio) was formed on the substrate of Example 1 in an amount of about 0.5 μm.
Provided. 1 g of the hole transfer material used in Example 1
And a solution of 1 g of resin dissolved in 18 g of tetrahydrofuran was applied to provide a 12 μm charge transport layer. When the transfer potential of this photosensitive member was measured in the same manner as in Example 17, the result was -50 V in the unexposed area and 0 V in the exposed area.

[0058]

INDUSTRIAL APPLICABILITY In the single-layer type electrophotographic photoreceptor of the present invention, the organic hole transporting substance and the charge generating material are dispersed in a binder having a ferroelectric property, or an organic acceptor compound is further added. Since it has the above constitution, when it is used in an electrostatic transfer process, a high transfer potential is obtained and a good image is obtained.

[Brief description of drawings]

FIG. 1A is an explanatory view of a single-layer type electrophotographic photosensitive member of the present invention. (B) is an explanatory view of another single-layer type electrophotographic photosensitive member of the present invention.

FIG. 2 is an explanatory diagram of a transfer process of a transfer latent image in a sequential transfer method.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hiroshi Kondo 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (14)

[Claims] 1. A charge-generating substance, an organic hole-transporting substance, and an organic acceptor compound at least 1 each on a conductive substrate.
A single-layer type in which an electrophotographic photoreceptor having a photosensitive layer composed of a single film of which at least one kind is dispersed in a binder, the binder is made of a polymer material exhibiting ferroelectricity Electrophotographic photoreceptor. 2. An electrostatic latent image is formed on an electrophotographic photosensitive member, and then an electrostatic recording member is brought into contact with the surface side of the photosensitive member, and a voltage is applied between the photosensitive member and the electrostatic recording member. Then, an electrostatic latent image corresponding to the photoconductor is transferred onto the electrostatic recording body, and thereafter, an electrostatic latent image transfer electrophotography used to visualize the electrostatic latent image on the electrostatic recording body. A single-layer type electrophotographic photoreceptor for transferring a latent image, wherein the single-layer type electrophotographic photoreceptor of claim 1 is used as the photoreceptor. 3. The electrophotographic photosensitive member according to claim 1, wherein the weight composition ratio of the organic hole transport material and the organic acceptor compound is in the range of 1/5 to 50/1. 4. The electrophotographic photosensitive member according to claim 1, wherein the binder is a fluororesin. 5. The electrophotographic photosensitive member according to claim 1, wherein the binder is a nylon resin having the following repeating unit (1). [Chemical 1] (In the formula, m and n are 1, 3, 5, 7, and 9, and x represents the degree of polymerization.) 6. The electrophotographic photosensitive member according to claim 1, wherein the binder is a urethane resin having the following repeating unit (2). [Chemical 2] (In the formula, m is 6, 7 and n is 3, 5 and x represents the degree of polymerization.) 7. The electrophotographic photosensitive member according to claim 1, wherein the binder is a thiourea-based resin having the following repeating unit (3). [Chemical 3] (In the formula, m is 5, 7, 9 and x represents the degree of polymerization.) 8. The hole transport material is represented by the following general formula (4):
4. The latent image transfer according to claim 1, which is a compound
Electrophotographic photoconductor. (In the formula, Ar₁, Ar₂And Ar₃Is an unsubstituted or
Alkyl group, alkoxy group, thioalkoxy group, aryl
Oxy group, halogen atom, cyano group, nitro group or
Represents an aryl group substituted with an amino group or a heterocyclic group
You ) 9. The electrophotographic photoreceptor for transferring a latent image according to claim 1, wherein the hole transporting substance is a compound represented by the following general formula (5). [Chemical 4] (In the formula, R ₁ and R ₂ represent a hydrogen atom, an alkyl group or an aryl group, and may form a ring between R ₁ and R _2. Ar ₁ represents an arylene group or a heterocyclic group. . Ar ₂
And Ar ₃ represents an alkyl group, an aryl group, or a heterocyclic group. ) 10. The hole transport material is represented by the following general formula (6).
The latent image transfer according to any one of claims 1 to 3, which is a compound to be transferred.
Electrophotographic photoreceptor for copying. (In the formula, Ar₁, Ar₂And Ar₃Is an unsubstituted or
Alkyl group, alkoxy group, halogen atom, cyano group,
An aryl group substituted with a toro group or an amino group, or
Represents a heterocyclic group. ) 11. The electrophotographic photoreceptor for transferring a latent image according to claim 1, wherein the hole transporting substance is a compound represented by the following general formula (7). [Chemical 5] (In the formula, Ar ₁ , Ar ₂ and Ar ₅ and Ar ₆ are unsubstituted,
Alternatively, it represents an aryl group substituted with an alkyl group, an alkoxy group, a halogen atom, a cyano group, a nitro group or an amino group, and Ar ₃ and Ar ₄ represent an arylene group which is unsubstituted or substituted with the above substituents. ) 12. The electrophotographic photoreceptor for transferring a latent image according to claim 1, wherein the hole transporting substance is a compound represented by the following general formula (8). [Chemical 6] (In the formula, Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ represent an aryl group which is unsubstituted or substituted by an alkyl group, an alkoxy group, a halogen atom, a cyano group, a nitro group or an amino group, and X is an alkylene. Group, sulfur, oxygen, or (CH =
CH) _n (n is an integer of 1 or more). ) 13. The hole transport material is represented by the following general formula (9).
The latent image transfer according to any one of claims 1 to 3, which is a compound to be transferred.
Electrophotographic photoreceptor for copying. (In the formula, Ar₁Is an unsubstituted or alkyl group,
Xy group, halogen atom, cyano group, nitro group or
Represents an aryl group or a heterocyclic group substituted with a mino group,
r₂And Ar₃Is an alkyl group, phenyl group or naphthyl group
Represents ) 14. The electrophotographic photosensitive member for latent image transfer according to claim 1, wherein the hole transporting substance is a compound represented by the following general formula (10). [Chemical 7] (In the formula, Ar ₁ , Ar ₂ , Ar ₃ and Ar _{4 each} represent an unsubstituted or alkyl group, an alkoxy group, an aryl group substituted with a halogen atom or an amino group, or a heterocyclic group. Represents an integer of 0 or 1.)