JPH04186359A - Electrophotographic sensitive body, device for electrophotography equipped with electrophotographic sensitive body and facsimile - Google Patents

Abstract

PURPOSE:To provide high sensitivity at the electrophotographic characteristic of an electrophotographic sensitive body and obtain excellent durablity by using a compound of a specific structure in a photosensitive layer. CONSTITUTION:A photosensitive layer contains a compound indicated by the formula I. In the formula I, R1 to R4 indicate alkyl group, aralkyl group, aromatic cyclic group, heterocyclic group, (CH=CH)nR5, cyano group or nitro group and R5 indicates aromatic cyclic group, heterocyclic group or nitro group and (n) an integral number 1 or 2. At least more than two of the R1 to R4 indicate nitrothiophene or dinitrothiophene group. Thereby an electrophotographic sensitive body has large sensitivity and has its electrophotographic characteristic maintained in a stable state when used repeatedly.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, an electrophotographic device, and a facsimile, and more specifically, an electrophotographic photoreceptor having a photosensitive layer containing a compound having a specific structure; The present invention relates to an electrophotographic apparatus and a facsimile equipped with the electrophotographic photoreceptor.

[Prior Art] Conventionally, inorganic photoreceptors having a photosensitive layer containing selenium, zinc oxide, cadmium sulfide, etc. as main components have been widely used as electrophotographic photoreceptors. Although these materials have certain basic properties, they have problems such as difficult film formation, poor plasticity, and high manufacturing costs. Furthermore, inorganic photoconductive materials are generally highly toxic, and there are significant restrictions in manufacturing and handling.

On the other hand, organic photoreceptors mainly composed of organic photoconductive compounds have many advantages such as compensating for the above-mentioned drawbacks of inorganic photoreceptors.
It has attracted attention in recent years, and many proposals have been made so far.
Some of these have been put into practical use.

Such organic photoreceptors include photoconductive polymers typified by poly-N-vinylcarbazole, and 2,4
．． Electrophotographic photoreceptors have been proposed whose main component is a charge transfer complex formed from a Lewis acid such as 7-dolinitro and 9-fluorenone. Although these organic photoconductive polymers are superior to inorganic photoconductive materials in terms of light weight and film formability, they are inferior in terms of sensitivity, durability, and stability against environmental changes, so they are not always satisfactory. It's not a thing.

On the other hand, functionally separated electrophotographic photoreceptors, in which charge generation and charge transport functions are divided into separate materials, have improved sensitivity and durability, which were considered to be lacking in conventional organic photoreceptors. . Such a functionally separated electrophotographic photoreceptor has the advantage that it has a wide selection range of materials for each of the charge generating substance and the charge transporting substance, and that it is relatively easy to manufacture an electrophotographic photoreceptor having arbitrary characteristics. .

As charge-generating materials, various azo pigments, polycyclic quinone pigments, cyanine dyes, squaric acid dyes, biryllium dyes, and the like are known.

Among them, many materials have been proposed for azo pigments because of their strong light resistance, high charge generation ability, and ease of material synthesis.

On the other hand, as a charge transport material, for example, Japanese Patent Publication No. 52-418
Pyrazoline compound described in Publication No. 8, Japanese Patent Publication No. 55-423
Hydrazone compounds described in JP-A-80 and JP-A-55-52063; triphenylamine compounds described in JP-A-58-32372 and JP-A-61-132955; Stilbene compounds described in JP-A-58-198043 are known.

However, most of the charge transport materials mentioned here and the charge transport materials used in organic electrophotographic photoreceptors that have been put into practical use so far have hole transport properties. Conventionally, photoreceptors using charge-transporting materials with hole-transporting ability are
Since the substrate, charge generation layer, and charge transport layer are sequentially laminated and used, the photoreceptor is charged with negative polarity. Therefore, there is a problem that the photoreceptor is chemically altered by the ozone generated by negative charging, and it has the drawback that printing resistance is significantly lower than that of inorganic photoreceptors such as a-Se or a-3i. Ta.

In addition, as a countermeasure against deterioration of photoreceptors due to ozone generated by negative charging, electrophotographic photoreceptors that use a substrate, a charge transport layer, and a charge generation layer are sequentially laminated, and electrophotographic photoreceptors that have a protective layer on top of them. has been proposed, for example, in Japanese Patent Laid-Open No. 61-753555 and Japanese Patent Laid-Open No. 54-58445.

However, in an electrophotographic photoreceptor having such a layer structure, since the relatively thin charge generation layer is the upper layer, characteristics deteriorate significantly due to wear during repeated use.

In addition, in electrophotographic photoreceptors provided with a protective layer for the purpose of improving this, since the protective layer material is an organic insulating material,
The potential is not stable during repeated defecation, and stable characteristics cannot be maintained repeatedly.

won.

Based on the above comments, it is expected that an organic electrophotographic photoreceptor will be developed that can be used for positive charging by sequentially laminating a substrate, a charge generation layer, and a charge transport layer.

However, this requires a charge transport material that has electron transport ability. ii) As charge transport materials having electron transport ability, for example, dicyanomethylene fluorene carboxylate compounds such as 2,4,7-dolinitro-9-fluorenone (TNF), disclosed in JP-A-61-148159, and JP-A-63-70257 have been used. No. Publication, JP-A-53-
Anthraquinodimethane compounds disclosed in JP-A No. 72664 and JP-A-63-104061, JP-A-63-8
1,4-naphthoquinone compound disclosed in No. 5749, JP-A-63-175860 and JP-A-63-17
Diphenyldicyanoethylene compound disclosed in Publication No. 4993, Proceedings of the 58th Spring Annual Meeting of the Chemical Society of Japan (3I 838)
, 431, (1989) and the like have been proposed.

However, photoreceptors for positive charging using these charge transport materials with electron transport ability do not have sufficient sensitivity, have a high residual potential after repeated use, are expensive to manufacture, and require the use of organic diaphragms and binders. There are problems such as low compatibility with
Further improvement is required.

[Problems to be Solved by the Invention] An object of the present invention is to solve various drawbacks of conventional electrophotographic photoreceptors by using a specific compound that satisfies the characteristics required of the charge transport compound described above. To provide an electrophotographic photoreceptor that eliminates the above problems, that is, has high sensitivity and can stably maintain electrophotographic characteristics during repeated use, and further to provide an electrophotographic apparatus equipped with the electrophotographic photoreceptor. , it is an object of the present invention to provide a facsimile machine incorporating the electrophotographic device.

[Means for Solving the Problems, Effects] The present invention is an electrophotographic photoreceptor having a photosensitive layer on a conductive support, characterized in that the photosensitive layer contains a compound represented by the following general formula (1). Consists of an electrophotographic photoreceptor.

In the general formula, R3, R2, R3 and R4 are an alkyl group, an aralkyl group, an aromatic ring group, a heterocyclic group, →CH= CH+-r
-R6 represents a cyano group or a nitro group, R6 represents an aromatic ring group, a heterocyclic group or a nitro group, and n represents an integer of 1 or 2.

However, at least two or more of R1 to R4 represent a nitrothiophene group or a dinitrothiophene group.

Specifically, alkyl groups include methyl, ethyl, propyl, and butyl, aralkyl groups include benzyl, phenethyl, and naphthylmethyl, aromatic ring groups include phenyl and naphthyl, and heterocyclic groups include groups such as phenyl and naphthyl. Examples of substituents include thienyl, pyridyl, and furyl, and substituents include alkyl groups such as methyl, ethyl, propyl, and butyl, halogen atoms such as fluorine, chlorine, and bromine, and cyan or nitro groups. Can be mentioned.

Further, the present invention comprises an electrophotographic apparatus equipped with the electrophotographic photoreceptor of the present invention.

Further, the present invention comprises an electrophotographic apparatus equipped with the electrophotographic photoreceptor of the present invention, and a facsimile machine characterized by having a receiving means for receiving image information from a remote terminal.

Representative examples of the compound represented by general formula (1) are listed below. However, it is not limited to these compounds.

An example method is to describe only the parts that change in the basic type.

Basic compound example (1) Rl: fNos Rt: +N(hR,:
Compound example (2) R,: ? NOa R: o-cgRs knee/4 and NOa R,: Now cg compound example (3) Compound example (4) R,: -CN R4: -CN compound example (
5) R, 2 --(q No 2 R,:
-C113 Compound Example (6) R, 9NO□ R, knee N02 R8: 仝NO□ R4 knee CN.

Compound Example (7) R,: -9-No□ R2: + No□R, knee C mountain it) R, Shibun CH.

Compound example (8) Rl: + No□ R2: (and No□R3: -
CN R,: -C,H.

Compound example (9) R,: +No□ R,: -9-No□R3・-C
H=CH-No, R4: -C1 (3 compound examples (
10) R1: +NO□ R,: +Na.

R,: -(cH=cH)z-NO2 R4ney CH3 Compound example (11) R1 NO□ R,: -9-No2R3:
R4:9 Compound Example (12) R1:+Noz R2:ReiNO□ Compound Example (13) R1・-/! ＞No□ R, (enemy Not R, knee OR
, Knee @ Compound Example (14) R1:+NO□ R2: +NO□ No□Example (15) R,: -Q-No□ R2,仝N02R3゛:T
R4 Knee CN Compound Example (16) Compound Example (17) Compound Example (18) Compound Example (19) R2:9NO2R, Knee@-CJs Compound Example (20) R, Knee (and No, R,: -CH.

Compound example (21) R1:÷NO□ R2-mountain Rj: +NO□ R4 knee C mountain (tl Compound example (2
2) R1: Pen NORRz knee (:N R8・+NO□ R, knee CN Compound example (23) R1: (and No, R, knee CN Rs: + NOa R4: @ Compound example (24)
) R, :+rio□R2, knee cH=cu%erR1・+
NO□ Rag-No□ Compound example (25) R,: +Na, R, -C high compound example (26) R1: +Na, R2 knee @ Rs: + NO2 R4 knee C4 H @ It) compound example (27
) Compound Example (28) Compound Example (29) Compound Example (30) Compound Example (31) Compound Example (32) R@: -CR2Ra: +NOx Compound Example (33)
) R,,+HO,R,: +CN The electrophotographic photoreceptor of the present invention is composed of a combination of a charge transporting material represented by the general formula (1) and a suitable charge generating material.

Examples of the structure of the photosensitive layer include the following configurations.

(1) Conductive support / layer containing a charge generating substance / layer containing a charge transporting substance laminated in sequence (2) Conductive support /
Layer containing a charge transporting substance/layer containing a charge generating substance (3) Conductive support/layer containing a charge generating substance and a charge transporting substance (4) Conductive support/containing a charge transporting substance (5) Conductive support/layer containing charge generating substance/layer containing charge generating substance and layer containing charge transporting substance are sequentially laminated according to the present invention. The compound represented by the general formula (1) has a high ability to transport electrons, and therefore can be used as a charge transport material in the photosensitive layer of the above type.

When the photosensitive layer has a form (1), it is preferably positively charged, when (2) it is preferably negatively charged, and in cases (3), (4), and (5), either positively or negatively charged can be used. .

Furthermore, in the electrophotographic photoreceptor described above, a protective layer or an undercoat layer may be provided on the photosensitive layer in order to improve adhesion and control charge injection.The structure of the electrophotographic photoreceptor may differ from the above basic structure. It is not limited.

Note that among the above configurations, the form (1) is particularly preferable,
This will be explained in more detail below.

Examples of the conductive support include those in the form shown below.

(1) Aluminum, aluminum alloy, stainless steel,
A metal such as copper made into a plate or drum shape.

(2) Non-conductive supports such as glass, resin, paper, etc.
A film formed by depositing or laminating a metal such as aluminum, palladium, rhodium, gold, or platinum on the conductive support of 1).

(3) Non-conductive supports such as glass, resin, paper, etc.
1) A layer of a conductive compound such as a conductive polymer, tin oxide, or indium oxide is formed on a conductive support by vapor deposition or coating.

Examples of effective charge generating substances include the following substances. These charge generating substances may be used alone or in combination of two or more types.

(1) Azo pigments such as monoazo, bisazo, trisazo, etc. (2) Phthalocytinine pigments such as metal phthalocyanine and non-metal phthalocyanine (3) Indigo pigments such as indigo and thioindigo (4) Perylenic acid anhydride, perylenic acid imide, etc. perylene pigments (5) polycyclic quinine pigments such as anthraquinone and pyrenequinone (6) squarylium pigments (7) biryllium salts and thiopyrylium salts (8) triphenylmethane pigments (9) selenium, amorphous silicon, etc. A layer containing an inorganic charge-generating substance, that is, a charge-generating layer, can be formed by dispersing the above-mentioned charge-generating substance in a suitable binder and coating it on a conductive support. can. It can also be formed by forming a thin film on a conductive support by a dry method such as vapor deposition, sputtering, or CVD.

The above binder can be selected from a wide range of binding resins.
For example, polycarbonate, polyester, polyarylate, butyral resin, polystyrene, polyvinyl acecool, diallyl phthalate resin, acrylic resin, methacrylic resin, vinyl acetate resin, phenolic resin, silicone resin, polysulfone, styrene-butadiene copolymer, alkyd resin, Examples include, but are not limited to, epoxy resins, urea resins, vinyl chloride-vinyl acetate copolymers, and the like. These resins may be used alone or in combination as a copolymer.

The amount of resin contained in the charge generation layer is preferably 80% by weight or less, preferably 40% by weight or less. Further, the thickness of the charge generation layer is preferably 5 LLm or less, particularly a thin film layer with a thickness of 0.01 to 2 um. Further, various sensitizers may be added to the charge generation layer.

A layer containing a charge transporting substance, that is, a charge transporting layer, can be formed by combining the compound represented by the general formula (1) and a suitable binding resin.

Examples of the binding resin used in the charge transport layer include those used in the charge generation layer, and further include photoconductive polymers such as polyvinylcarbazole and polyvinylanthracene.

The blending ratio of this binding resin and the compound represented by general formula (1) is 10 to 50 parts by weight of the compound per 100 parts by weight of the binder.
Preferably, the amount is 0 parts by weight.

Since the charge transport layer has a limit to its ability to transport charge carriers, it cannot be made thicker than necessary;
A range of 0 μm, particularly 10 to 30 μm is preferred.

Furthermore, an antioxidant, an ultraviolet absorber, a plasticizer, or a known charge transport substance may be added to the charge transport layer, if necessary.

When forming such a charge transport layer, a coating method such as a dip coating method, a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, or a blade coating method is used using an appropriate organic solvent. It can be carried out.

The electrophotographic photoreceptor containing the compound represented by the above general formula (1) in the charge transport layer is used not only in electrophotographic copying machines, but also in electrophotographic application fields such as laser printers, CRT printers, and electrophotographic plate making systems. It can also be widely used.

Next, an electrophotographic apparatus and a facsimile equipped with the electrophotographic photoreceptor of the present invention will be described.

FIG. 1 shows a schematic configuration of a general transfer type electrophotographic apparatus using the drum type photoreceptor of the present invention.

In the figure, reference numeral 1 denotes a drum-type photoreceptor as an image carrier, which is rotated at a predetermined circumferential speed in the direction of the arrow around an axis 1a. During the rotation process, the photoreceptor 1 is uniformly charged to a predetermined positive or negative potential on its circumferential surface by the charging means 2, and then exposed to a light image by an image exposure means (not shown) in the exposure section 3, such as slit exposure/laser. beam scanning exposure, etc.).

As a result, electrostatic latent images corresponding to the exposed images are sequentially formed on the circumferential surface of the photoreceptor.

The electrostatic latent image is then developed with toner by the developing means 4,
The toner developed image is sequentially transferred by the transfer means 5 from a paper feeding section (not shown) onto the surface of the transfer material P, which is fed between the photoreceptor l and the transfer means 5 in synchronization with the rotation of the photoreceptor 1. To go.

The transfer material P that has undergone the image transfer is separated from the photoreceptor surface and introduced into the image fixing means 8, where the image is fixed and a copy is produced.
will be printed out on the outside of the aircraft.

After the image has been transferred, the surface of the photoreceptor 1 is cleaned by a cleaning means 6 to remove residual toner, and subjected to a charge removal process by a pre-exposure means 7, and is repeatedly used for image formation.

As the uniform charging means 2 for the photoreceptor 1, a corona charging device is generally widely used.

Further, as for the transfer device 5, a corona transfer means is generally widely used.

An electrophotographic apparatus is constructed by combining a plurality of components such as the above-mentioned photoreceptor, developing means, and cleaning means into an apparatus unit, and this unit is configured to be detachable from the apparatus main body. It's okay. For example, the photoreceptor 1 and the cleaning means 6 may be integrated into one device unit, and configured to be detachable using a guide means such as a rail of the device body. At this time, the above-mentioned device unit may include a charging means and/or a developing means.

In addition, when an electrophotographic device is used as a copying machine or a printer, light image exposure involves scanning the reflected light or transmitted light from the document, or by reading the document and converting it into a signal. driving the array,
Alternatively, it is performed by driving a liquid crystal shutter array.

Furthermore, when used as a facsimile printer, the optical image exposure is exposure for printing received data.

FIG. 2 is a block diagram showing an example of this case.

A controller 10 controls an image reading section 9 and a printer 18.

The entire controller 10 is controlled by a CPL 116.

The read data from the image reading section is transmitted to the partner station through the transmitting circuit 12. Data received from the partner station is sent to the printer 18 through the receiving circuit 11. Predetermined image data is stored in the image memory. A printer controller 17 controls a printer 18. 13 is a telephone.

Images received from the line 14 (image information from a remote terminal connected via the line) are demodulated by the receiving circuit 11, and then the CPU 16 performs signal processing on the image information and sequentially stores it in the image memory 15. . When one page of image information is stored in the memory 16, the CPU 16 reads the image information of one page from the memory 15 and stores the image information of the one page signaled to the printer controller 17. Send image information.

When the printer controller 17 receives one page of image information from the CPU 16, it controls the printer 18 to record the image information of that page.

Note that during recording by the printer 18, the CPU 16
The next page is being received.

As described above, images are received and recorded.

[Examples] Example 1 4 g of oxytitanyl phthalocyanine obtained according to the production example disclosed in JP-A No. 61-239248
polyvinyl butyral (butyralization degree 70 mol%,
Weight average molecular weight 40,000) 2g to cyclohexanone 95m9
A coating solution was prepared by dispersing the solution in a sand mill for 24 hours.

This coating solution was diluted and coated onto an aluminum sheet using a Mayer bar so that the film thickness after drying was 012 um to form a charge generation layer.

Next, 5 g of Compound Example (4) as a charge transport material and 7 g of polycarbonate C (weight average molecular weight: 35,000) were dissolved in 100 g of chlorobenzene, and this solution was applied onto the charge generation layer using a Mayer bar and dried. A charge transport layer having a thickness of 17 um was formed to produce an electrophotographic photoreceptor.

This electrophotographic photoreceptor was tested using an electrostatic copying paper tester EPA-8100 manufactured by Kawaguchi Electric Co., Ltd. using the static method.
After corona charging with KV and holding for 1 second in the dark, the illumination intensity was 2.
It was exposed to light at 0 lux and its charging characteristics were examined.

The charging characteristics include the surface potential (vo), the exposure amount (El/2) required to attenuate the potential (V, ) by 1/2 after dark decay for 1 second, and 5 seconds after the start of light irradiation. potential (V+t
) was measured.

Furthermore, in order to measure the fluctuations in bright area potential and dark area potential when repeatedly used, the electrophotographic photoreceptor prepared above was
Canon ■ Copy 1! It was attached to the photoreceptor drum cylinder of INP-6650 and 2,000 copies were made using a modified machine of the same machine, and the changes in dark area potential (vo) and light area potential (VLl) were measured at the initial stage and after 2,000 copies were made. .

In addition, the initial VO and ■5 are +650V and +150V, respectively.
It was set so that Show the results.

■. :+690V V, :+680V ” El/2:3.6j2ux-sec V*:+55V Initial potential Vo :+650V VL :+150V Potential after 2,000-sheet durability V, :+655V VL: +140V Example 2 to log and Comparative example 1 ~4 This example uses Compound Examples (1), (2), and (11) instead of Compound Example (4) as the charge transport compound used in Example 1.
), (14), (16), (20), (23), (28
) and (30) and in the same manner as in Example 1 except that an electrophotographic photoreceptor was prepared. Then, the electrophotographic characteristics of each electrophotographic photoreceptor were measured in the same manner as in Example (1).

For comparison, an electrophotographic photoreceptor was prepared using the following comparative compound as a charge transporting compound and the other conditions were the same, and the electrophotographic properties were measured.

Show the results.

Comparative compound example (1) Comparative compound example (2) Comparative compound example (3) Comparative compound example (4) 2 (1) 710 700 3.03
(2) 705 690 2.74 (11)
710 695 3.35 (14) 700
685 3.26 (16) 700 690
3.57 (20) 710 705
3.18 (2317006902,9 9(28) 710 700 3.710
(3037106952, 9V, ++V1 1 (1) 700 680 8.
0 Comparative example V6 ÷ V) Note: - As is clear from the above results due to poor sensitivity, when used as a charge transport compound, the compound represented by the general formula (1) of the present invention, when used as a charge transport compound, It can be seen that the electrophotographic photoreceptor has extremely excellent sensitivity and potential stability during repeated use.

Example 11 A solution prepared by dissolving 5 g of N-methoxymethylated 6-nylon resin (weight average molecular weight: 200,000) and alcohol-soluble copolymerized nylon resin (weight average molecular weight: 80,000) in 100 g of methanol was placed on an aluminum substrate using a Mayer bar. An undercoat layer having a thickness of 1LLm after drying was formed.

Next, 1 g of a charge generating substance having the following structural formula and 0.4 g of polyvinyl butyral (degree of butyralization 70%, weight average molecular weight 100,000) and 50 g of dioxane were dispersed in a ball mill for 20 hours. After diluting this dispersion, it was applied onto the previously formed undercoat layer by a blade coating method to form a charge generation layer having a thickness of 0.2 um after drying.

Next, Compound Log of Compound Example (18) and 10 g of polymethyl methacrylate (weight average molecular weight 80,000) were dissolved in chlorobenzene long, and applied onto the previously formed charge generation layer by a blade coating method. A charge transport layer having a thickness of 17 μm was formed.

A +6 KV corona discharge was applied to the electrophotographic photoreceptor thus prepared. The surface potential (Vo) at this time was measured. Furthermore, the surface potential after leaving this photoreceptor in a dark place for 1 second (
vi was measured. Sensitivity is calculated by dividing the potential V1 after dark decay by 1/
Exposure amount required to attenuate to 2 (El/l: JJJ
/Cm'') and the residual potential (■lI) after exposure with a light intensity of 20 μJ/cm''. At this time, the light source was a gallium/aluminum/arsenic ternary semiconductor laser (output: 5 mW; oscillation wavelength: 7
80 nm) was used. Show the results.

V,: +700V, V,: +690V E+zx: 2. l uJ/cm" V,: +60V Next, the above photoconductor was attached to a modified Canon NP-9330, which is a reversal development type digital copying machine equipped with the same semiconductor laser as above, and an actual image forming test was carried out. I did it.

The settings were as follows: surface potential after primary charging: +600 V, surface potential after image exposure: +1 OOV (exposure amount: 4.9 μJ/cm"), and good prints of both characters and images were obtained.

In addition, after continuously printing 5,000 images, 5
Stable prints were obtained up to 1,000 sheets.

Example 12 7 g of oxytitanyl phthalocyanine obtained according to the production example disclosed in JP-A No. 62-67094 was added to log cyclohexanone and 4 g of polyvinyl benzal (degree of benzalization 78 mol%, weight average molecular weight 100,000) was added to Nagisa. The mixture was added to the filtered liquid and dispersed in a ball mill for 48 hours.

After diluting this dispersion, it was applied onto an aluminum sheet using a Mayer bar and dried at 90° C. for 0.5 hours to form a charge generation layer of 0.2 μm.

Next, 5 g of compound example (26) and bisphenol Z
Type polycarbonate resin (weight average molecular weight 100,000) 5g
was dissolved in 80 g of chlorobenzene and applied onto the previously formed charge generation layer using a Mayer bar, and dried at 140° C. for 1 hour to form a charge transport layer of 18 μm.

The thus produced electrophotographic photoreceptor was measured in the same manner as in Example 11.

V,: +700V, V,: +695V El/2: 1.8uJ/cm” VR: +55V Example 13 A 5% methanol solution of alcohol-soluble copolymerized nylon (weight average molecular weight 50,000) was applied onto an aluminum substrate. A subbing layer having a thickness of 0.5 μm after drying was formed.

Next, 5 g of a pigment represented by the following structural formula was dispersed in 50 mβ of tetrahydrofuran using a sand mill.

Next, 5 g of compound example (12) and 7 g of polycarbonate (weight average molecular weight 50,000) were mixed with chlorobenzene (70
parts by weight) - dissolved in 50 g of dichloromethane (30 parts by weight) solution, added to the previously prepared dispersion, and further mixed with a sand mill for 2.
Dispersed for 5 hours.

This dispersion was applied to the previously formed undercoat layer so that the film thickness after drying was 1.
It was coated with a Mayer bar to a thickness of 8 μm and dried.

The charging characteristics of the electrophotographic photoreceptor thus prepared were measured in the same manner as in Example 1. Show the results.

■. :+700V V, :+690VE+z*
:4. Ol2ux-secV*: +65V Example 14 5 g of compound example (25) as a charge transport material and 5 g of polycarbonate resin (weight average molecular weight 80,000) were dissolved in 70 g of chlorobenzene, and this solution was applied onto an aluminum sheet using a Mayer bar. A charge transport layer having a dry film thickness of 18 μm was formed.

Next, 2 g of a disazo pigment having the following structural formula was dispersed in a sand mill for 20 hours with a solution of 1.5 g of polyvinyl butyral (butyralization degree: 80 mol %) dissolved in 50 ml of cyclohexanone to prepare a coating solution.

After diluting this coating solution, it was applied onto the charge transport layer using a Mayer bar to a dry film thickness of 0.5 μm to form a charge generation layer, thereby producing an electrophotographic photoreceptor.

This electrophotographic photoreceptor was tested in a static manner using an electrostatic copying paper tester EPA-8100 manufactured by Kawaguchi Denki ■.
After corona charging with KV and holding for 1 second in the dark, the illumination intensity was 2.
It was exposed to light at 0 lux and its charging characteristics were examined.

The charging characteristics include the exposure amount (El/2) necessary to attenuate the surface potential (VO) and the potential (Vl) when dark decayed for 1 second to 1/2, and the irradiation with a light amount of 100 lux・sec. The residual potential (V8) after that was measured.

Show the results.

vo knee 700V V, 2 -
690VE+/z: 3.8I2ux5sec VR: +50V [Effects of the Invention] The electrophotographic photoreceptor of the present invention uses a compound with a specific structure in the photosensitive layer, so that the electrophotographic properties of the electrophotographic photoreceptor have high sensitivity, In addition, during continuous image formation by repeated charging and exposure, fluctuations in bright and dark potentials are small.
It is effective in exhibiting the remarkable effect of being excellent in durability.

Furthermore, similar effects can be achieved in electrophotographic devices and facsimile machines equipped with the electrophotographic photoreceptor.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a general transfer type electrophotographic apparatus using the drum type photoreceptor of the present invention. Reference numeral 1 denotes a drum-type photoreceptor (electrophotographic photoreceptor of the present invention) as an image carrier, 2 a corona charging device, 3 an exposure section, 4
is a developing means, 5 is a transfer means, 6 is a cleaning means, 7
8 is a pre-exposure means, 8 is an image fixing means, L is a light image exposure, and P is a transfer material subjected to image transfer. FIG. 2 is a block diagram of a facsimile machine using an electrophotographic device as a printer. Reference numeral 9 is an image reading unit, 10 is a controller, 11 is a receiving circuit, 12 is a transmitting circuit, 13 is a telephone, 14 is a line, 1
5 is an image memory, 16 is a CPU, 17 is a printer controller, and 18 is a printer.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a compound represented by the following general formula (1). General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (1) In the formula, R_1, R_2, R_3 and R_4 are alkyl groups, aralkyl groups, aromatic ring groups, heterocyclic groups, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ , represents a cyano group or a nitro group, R_5 represents an aromatic ring group, a heterocyclic group, or a nitro group, and n
represents an integer of 1 or 2. However, at least two or more of R_1 to R_4 are
Indicates a nitrothiophene group or a dinitrothiophene group. 2. An electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1. 3. A facsimile machine comprising an electrophotographic apparatus equipped with the electrophotographic photoreceptor according to claim 1 and a receiving means for receiving image information from a remote terminal.