JPS62208054A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the sensitivity and stability in potential of a photosensitive body by using a specific fluorene compd. as an electric charge transfer material. CONSTITUTION:The fluorene compd. Expressed by the formula is incorporated preferably as the charge transfer material of a separated-function type photosensitive layer into the layer of the photosensitive body. R1-R6 in the formula denote an alkyl, aralkyl, aryl or heterocyclic group. The charge transfer layer is preferably formed by dissolving the fluorene compd. expressed by the formula and binder into a suitable solvent and coating the soln. on an electric charge generating layer. The sensitivity and potential stability of the photosensitive body are improved according to the above-mentioned constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to electrophotographic photoreceptors, and more particularly to electrophotographic photoreceptors containing low molecular weight organic photoconductors that provide improved electrophotographic properties.

[Prior Art] Inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide are conventionally known as photoconductive materials used in electrophotographic photoreceptors. Although these materials have many advantages, such as being able to be charged to an appropriate potential in the dark, having little charge dissipation in the dark, or being able to quickly dissipate charge when irradiated with light, they also have various drawbacks. For example, selenium-based photoreceptors have temperature and humidity.

Crystallization easily progresses due to factors such as dust and pressure, and particularly when the ambient temperature exceeds 40° C., crystallization becomes significant, resulting in drawbacks such as a decrease in charging performance and the appearance of white spots on images. Cadmium sulfide photoreceptors do not provide stable sensitivity in humid environments, and zinc oxide photoreceptors require the sensitizing effect of sensitizing dyes such as rose bengal. They have the disadvantage that they cannot provide stable images over a long period of time because the sensitive dyes undergo charging deterioration due to corona charging and photobleaching due to exposure light.

On the other hand, various organic photoconductive polymers including polyvinyllupasol have been proposed, but these polymers are superior to the above-mentioned inorganic photoconductive materials in terms of film formability and light weight. However, it has been difficult to put them into practical use to date because they still do not have sufficient film formation properties, and they are inferior to inorganic photoconductive materials in terms of sensitivity, durability, and stability against environmental changes. This was because

Also, hydrazone compounds disclosed in U.S. Pat. No. 4,150,987, triarylpyrazoline compounds described in U.S. Pat. No. 3,837,851, and JP-A-51-948
Low-molecular organic photoconductors such as 9-styrylanthracene compounds described in Japanese Patent Application Publication No. 28 and Japanese Patent Application Laid-Open No. 51-94829 have been proposed. By appropriately selecting the binder used, such low-molecular-weight organic photoconductors can overcome the drawbacks of film-forming properties that had been a problem in the field of organic photoconductive polymers. It cannot be said that the sensitivity is sufficient.

For this reason, in recent years, a laminated structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer has been developed. Electrophotographic photoreceptors using this laminated structure as a photosensitive layer can now be improved in terms of sensitivity to visible light, charge retention, surface strength, and the like.

As such an electrophotographic photoreceptor, for example, US Pat.
It is disclosed in the specification of No. 37851 and the specification of No. 3871882.

However, electrophotographic photoreceptors that use conventional low-molecular organic photoconductors in the charge transport layer do not always have sufficient sensitivity and characteristics, especially when subjected to repeated charging and exposure over a long period of time. There is a point that needs to be greatly improved in terms of fluctuations in bright area potential and dark area potential.

[Problems to be Solved by the Invention] It is an object of the present invention to provide an electrophotographic photoreceptor that eliminates the above-mentioned drawbacks or disadvantages, to provide a novel organic photoconductor, and to provide a charge generation layer and a charge transport layer. It is an object of the present invention to provide a novel charge transport material for functionally separated laminated photosensitive images.

[Means for Solving Problems, Effects] The present invention comprises an electrophotographic photoreceptor characterized by having a layer containing a fluorene compound represented by the following general formula.

In the formula, R1, R2, R3, R4, R5 and R6 represent an alkyl group, an aralkyl group, an aryl group or a heterocyclic group which may have a substituent, and R1 and R2, R3 and R4 are each a nitrogen atom Indicates a residue that together forms a heterocycle, and one of R5 and R6 may be a hydrogen atom.

More specifically, in the above general formula, R,, R2, R3, R
4, R5 and R6 are alkyl groups such as methyl, ethyl, propyl, butyl, aralkyl groups such as benzyl, phenethyl and naphthylmethyl, aryl groups such as phenyl and naphthyl, pyridyl, quinolyl, chenyl, furyl, carbazolyl, oxacylyl, Indicates a heterocyclic group such as imidazolyl, triazolyl indolyl, R1 and R2,
R3 and R4 represent residues that form a heterocycle, such as piperidine, morpholine, and carbazole, together with a nitrogen atom, and R1, R2, R3, R4, R5, and R6 may be the same or different, and R5 and R6 may be one of hydrogen atoms, and the above R1, R2, R3
, R4, R5 and R6 may include alkyl groups such as methyl, circular tyl and propyl, flukoxy groups such as methoxy and ethoxy, halogen atoms such as fluorine, chlorine and bromine, phenyl and naphthyl. Examples include aromatic ring groups, heterocyclic groups such as pyridyl, quinolyl, chenyl, and furyl, cyano groups, nitro groups, amide groups, and acyl groups.

Regarding the use of fluorene compounds, please refer to JP-A-Sho'5.
Although it is described in Publication No. 6-22437, the present inventors
As shown in the general formula above, durability and stability can be improved by introducing a substituent at the 9-position of the fluorene compound, and by introducing a substituent other than the benzyl group as Nm substitution. It was also found that the characteristics were improved.

Representative examples of the compounds represented by the general formula are listed below.

The abbreviations in the structural formula are as follows.

Me: CHB, Et: C, H5-, n-Bu:
n-C2O4 Compound Example Synthesis Example 1 of the Fluorene Compound with the Structural Formula Synthesis of Compound Example (25) 2.7-Diethylfluorene lO,og (51, Omm
3) was dissolved in 150 cc of tetrahydrofuran and heated to 0°C.
oily sodium hydride (60%) 12.24g (3
06, OmmoJL), return to room temperature, and stir for 30 minutes. Then, 47.74 g of ethyl bromide (306,O
mmoJL) was gradually added dropwise, and after stirring at room temperature for 1 hour, 8
After heating and refluxing the reaction solution for an hour, the reaction solution was left to cool, poured into 250 cc of water, and extracted with 120 cc of isopropyl ether.

After drying the organic layer over anhydrous sodium sulfate, the solvent was removed under reduced pressure and purified with a silica gel column to obtain 13.10 g of compound (25). The yield was 70.6%.

Elemental analysis value Actual value % Theoretical value % C82,4082,42 H9,929,89 N 7.68 7.69 Synthesis example 2 (synthesis of compound example (46)) Fluorene 10.0g (60.24mmol) was added to the above example Similarly, 9,9-diethylfluorene was synthesized from ethyl bromide in the presence of an alkali, and nitrated by a known method to obtain 9.
,9-diethyl-2,7-sinitrofluorene was synthesized. This compound was partially reduced with sodium hydrogen sulfide using a known method and reacted with iodobenzene to give 9,9-diethyl-7-dithod-2-diphenylaminofluorene.

This compound was reduced by a known method, and 6-41 g of Compound Example (46) was obtained from benzyl bromide in the presence of an alkali as in Synthesis Example 1.

The yield was 18.2%.

Elemental analysis value Actual value % Theoretical value %C88,348
8,36 H6,886,85 N 4.78 4.79 Compounds other than the above synthesis example compounds can generally be synthesized by the same method as the above example or by a known method.

In a preferred embodiment of the present invention, a compound represented by the above general formula is used as a charge transport material in an electrophotographic photoreceptor in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer.

The charge transport layer in the present invention is preferably formed by coating and drying a solution in which a fluorine-based compound represented by the above general formula and a binder are dissolved in a solvent. Examples of the adhesive include polyarylate, polysulfone, polyamide, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenol resin, epoxy resin, polyester, alkyd resin, polycarbonate, polyurethane, or repeating units of these resins. Copolymer 1 containing two or more of the following, such as styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-
Examples include maleic acid copolymers. In addition to such insulating polymers, organic photoconductive polymers such as polyvinylcarbazole, polyvinylanthracene, and polyvinylpyrene can also be used.

The blending ratio of this binder and the fluorene compound is:
It is preferable that the fluorene compound is contained in an amount of lO to sovLi parts per 100ffi parts of the binder.

The charge transport layer is electrically connected to the charge generation layer described below, receives and takes charge carriers injected from the charge generation layer in the presence of an electric field, and transports these charge carriers to the surface. It has the ability to At this time, this charge transport layer may be implanted on the charge generation layer,
Alternatively, the charge transport layer may be laminated under the charge generation layer, but it is preferable that the charge transport layer is laminated on the charge generation layer.This charge transport layer has a limit in its ability to transport charge carriers, so it is not necessary. The film thickness cannot be made thicker than that, and is generally 5 to 30 JL.

The preferred range is 8 to 20 liters.

The solvent used to form such a charge transport layer varies depending on the type of binder used, and is preferably selected from those that do not dissolve the charge generation layer or the subbing layer of the sub-layers.

Specific solvents include alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone, methyl ethyl ketone, and cyclohexanone;
-dimethylformamide.

Amides such as N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, methylene chloride, dichloroethylene, Carbon tetrachloride, aliphatic hydrocarbons such as trichlorethylene, benzene, toluene, xylene, ligroin, monochlorobenzene,
Aromatic hydrocarbons such as lorbenzene can be used.

Coating is done by dip coating method, spray coating method,
spinner coating method, bead coating method, Mayer-per coating method, blade coating method,
Roller coating method.

This can be carried out using a coating method such as a curtain coating method.

Drying is preferably carried out by drying to the touch at room temperature and then heating. Drying by heating can be carried out at a temperature of 30 to 200 ℃ for a time in the range of 5 minutes to 2 hours, either stationary or under ventilation.

The charge transport layer in the present invention can contain various additives. Such additives include diphenyl, diphenyl chloride, 0-terphenyl, p-terphenyl, dibutyl phthalate, dimethyl glycol phthalate, dioctyl phthalate, triphenyl phosphoric acid, and methylnaphthalene.

Examples include benzophenone, chlorinated paraffin, dilaurylthiopropionate, 3,5-dinitrosalicylic acid, and various fluorocarbons.

The charge generation layer in the present invention includes selenium, selenium-tellurium, biryllium dyes, thiapyrylium dyes, azulenium dyes, phthalocyanine pigments, andanthrone pigments, dibenzpyrenequinone pigments, vilanthrone pigments,
Trisazo pigments, disazo pigments, heptanoazo pigments, indigo pigments, quinacridone pigments, thiacyanine, asymmetric quinocyanine, quinocyanine or JP-A-1986-14
A separate vapor deposited layer or a resin dispersion layer selected from a charge generating material such as amorphous silicon as described in US Pat. No. 3,645 can be used.

Examples of the charge generating substance used in the electrophotographic photoreceptor of the present invention include the following inorganic compounds and organic compounds.

Charge generating substance (1) Amorphous silicon (2) Selenium-tellurium (3) Selenium-arsenic (4) Cadmium sulfide (1B) (2θ) (4G) (5B) (5 days) Methine squaric acid dye, dye (58)
Indigo dye (80) Thioindigo dye (81) β-type copper phthalocyanine (B2) (8B) (?8) (8B) (8 days) In the charge generation layer, the above charge generation substance is dispersed in a suitable binder. It can be formed by coating this on a substrate, or it can also be obtained by forming a vapor deposited film using a vacuum evaporation apparatus.

The binder that can be used when forming the charge generation layer by coating can be selected from a wide range of insulating resins, and
It can be selected from organic photocardiographic polymers such as N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene.

Preferably, polyvinyl butyral, polyarylate (
Insulating properties of polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinylpyridine, cellulose resin, polyurethane, casein, polyvinyl alcohol, polyvinylpyrrolidone, etc. Examples include resins.

The resin contained in the charge generation layer is suitably 80% by weight or less, preferably 40i% by weight or less.

Solvents used during coating include alcohols such as methanol, ethanol, and isopropanol, acetone,
Ketones such as methyl ethyl ketone and cyclohexanone, amides such as N,N-dimethylformamide and N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, tetrahydrofuran, dioxane,
Ethers such as ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate.

Aromatic hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, trichlorethylene, etc., benzene, toluene, xylene, ligroin, monochlorobenzene, dichlorobenzene, etc. Examples include the following.

Coating is done by dip coating method, spray coating method,
spinner coating method, bead coating method, Meyer bar coating method, blade coating method,
Roller coating method.

This can be carried out using a coating method such as a curtain coating method.

The charge generation layer contains as much of the charge generation substance as possible in order to obtain sufficient absorbance, and in order to shorten the range of the generated charge carriers, the thin film layer 1, for example, 5I
L or less, preferably 0. A thin film layer having a thickness of 01 to 1 is desirable.

This means that most of the incident light is absorbed by the charge generation layer, generating many charge carriers.

Furthermore, this is due to the fact that the generated charge carriers need to be injected into the charge transport layer without being deactivated by recombination or trapping.

A photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer is provided on a conductive substrate.

Examples of the substrate having a conductive layer include aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium molybdenum, chromium,
Examples include titanium, nickel, indium, gold, platinum, etc. Plastics (e.g. polyethylene, Polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin,
polyfluorinated ethylene, etc.), conductive particles (e.g., aluminum powder, titanium oxide, tin oxide, zinc oxide, carbon black, silver particles, etc.) together with a suitable binder on a plastic or the conductive substrate;
Examples include substrates made of plastic or paper impregnated with conductive particles, and plastics containing conductive polymers.

A subbing layer having barrier and adhesive functions can also be provided between the conductive layer and the photosensitive layer.

The undercoat layer is made of casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610.
It can be formed from nylon, alkoxymethylated nylon, polyurethane, gelatin, aluminum oxide, etc.

The thickness of the undercoat layer is 0.1 to 5 mm, preferably 0.5 mm.
A range of ~3IL is suitable.

When using a photoreceptor having a conductive layer, a charge generation layer, and a charge transport layer in this order, the substituted amino compound of the present invention is
Because it has hole transport properties, it is necessary to charge the surface of the charge transport material negatively, and when it is exposed to light after being charged, the holes generated in the charge generation layer are injected into the charge transport layer in the exposed area, and then reach the surface and become negatively charged. The charge is neutralized, the surface potential is attenuated, and an electrostatic contrast is created between the surface potential and the unexposed area. It is necessary to use positively charged toner during development.

In another specific example of the present invention, disazo pigments or biryllium dyes, thiapyrylium dyes, selenapyrylium dyes disclosed in U.S. Pat. No. 3,554,745, U.S. Pat.
Photoconductive pigments and dyes such as benzobyrylium dyes, benzothiapyryllium dyes, and naphthopyrillium dyes can also be used as sensitizers.

In yet another embodiment, a eutectic complex of a biryllium dye and an electrically insulating polymer having a fullkylidene diarylene moiety as disclosed in U.S. Pat. No. 3,684,502 may be used as a sensitizer.

This eutectic complex is, for example, 4-[4-bis-(2-chloroethyl)aminophenyl]-2.6-'; phenylthiapyrylium verchlorate and poly(4,4'-isopropylidene diphenylene carbonate). with a halogenated hydrocarbon solvent (e.g. dichloromethane, chloroform, carbon tetrachloride, 1.1-dichloroethane, 1.2-dichloroethane, 1.1.2-1-dichloroethane, chlorobenzene, fromobenzene, 1.2-dichlorobenzene) A particulate eutectic complex is obtained by adding a non-polar solvent such as hexane, octane, decane, 2,2,4-trimethylbenzene, ligroin.

The electrophotographic photoreceptor in this specific example includes styrene-butadiene copolymer, silicone resin, vinyl resin, vinylidene chloride-acrylonitrile copolymer, styrene-7crylonitrile copolymer, vinyl acetate-vinyl chloride copolymer, polyvinyl butyral, polymethyl methacrylate, poly-N-butyl methacrylate,
Polyesters, cellulose esters, etc. can be contained as a binder.

The electrophotographic photoreceptor of the present invention can be used not only for i-child photocopying machines, but also for laser printers, CRT printers,
It is also widely used in electrophotographic application fields such as electrophotographic plate making systems.

[Example] Example 1 β-type copper phthalocyanine (trade name: LionolBlue)
NCB Taner (manufactured by Toyo Ink Manufacturing Co., Ltd.) with water,
7 g of pigment purified by filtration after sequential reflux in ethanol and benzene, trade name Polyester 7 Dohesive 49
000 (solid content 20%, manufactured by DuPont), 35 g of toluene, and 35 g of dioxane were mixed and dispersed in a ball mill for 6 hours to prepare a coating liquid. This coating solution was applied onto an aluminum sheet to a dry film thickness of 0.5#1. A charge generation layer was formed by coating with a Mayer bar so that the charge generation layer was formed.

Next, the above fluorene compound example (2) is used as a charge transport material.
A solution obtained by stirring and dissolving 7 g of the substance in 5) and 7 g of polycarbonate (trade name Panrai K-1300, manufactured by Kijin ■) in a mixed solvent of 35 g of tetrahydrofuran and 35 g of chlorobenzene was placed on top of the charge generation layer. An electrophotographic photoreceptor having a photosensitive layer having a two-layer structure was prepared by coating with a Mayer bar to a dry film thickness of 111 L.

This electrophotographic photoreceptor was corona-charged at 15 KV using an electrostatic copying paper tester Model-5P-428 manufactured by Kawaguchi Electric Co., Ltd., held in a dark place for 1 second, and then exposed to light at an illuminance of 5 cm UX. The charging characteristics were measured.

As for the charging characteristics, the surface potential (Vo) is 1, and the potential (vl) when dark decayed for 1 second is 1. The exposure amount (E 1/2) required for attenuation to /2 was measured.

Furthermore, in order to measure the fluctuations in the bright area potential and dark area potential when the electrophotographic photoreceptor prepared above was used upside down, the photoreceptor prepared in this example was manufactured by Canon Corporation, and a PPC copying machine ( NP-150Z) was attached to a photosensitive drum cylinder and 50,000 copies were made using the same machine, and the changes in bright area potential (Vshi) and dark area potential (Vp) were measured at the initial stage and after 50,000 copies were made. It was measured.

Comparative sample l
was created and similar measurements were taken. The results are shown below.

VO(-V)Vl (-V)El/2 (lux, 5e
c) Example 1 686 685 1.90 Comparative sample 1
660 630 4.05 initial After 50,000 sheets durability Example I VD(-V) 686 678VL(
-V) 120 149 Comparative sample I VD(
-V) 865 640V -V) 187
39G From the above, it was confirmed that the electrophotographic photoreceptor of the present invention was significantly superior to the comparative sample in both sensitivity and potential stability.

In Examples 2 to 1, instead of the charge transport material used in Example 1,
Examples of fluorene compounds (2), (5) (7), (12)
, (17), (19), (22), (23), (35)
, (40), (43), (53), (5B), (66)
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the compounds (82) and (44) were used as the charge-generating substance.

The electrophotographic properties of each photoreceptor were measured in the same manner as in Example 1. The results are shown below.

Examples Compound examples vo vi El/2(-
V) (-V) (lux, 5ec)2 (
2) 686 668 1.923 (5)
895 681 2.904 (7) 6
94 679 2.645 (12) 690
675 2.506 (17) 685 665
2.107 (19) 660 62
0 2.018 (22) 682
671 1.979 (23) 685
674 2.1410 (35)
691 682 2.3511 (40)
686 689 2.0512 (43
) 682 668 2.1113
(53) 694 884 1.9114
(5B) 685 6B8 2.1
915 (82) 691 677
2.8516 (86) 694 68
5 2.11 early Example after 50,000 sheets durability VD Vw V) VL.

(-V) (-V) (-V) (-V
)2'685' 118 670 148
Example 17 An ammonia aqueous solution of casein (11.2 g of casein, 1 g of 28% ammonia water, 222 mA of water) was coated on an aluminum cylinder by dip coating and dried to form a subbing layer with a coating amount of 1.017 m2. did.

Next, as a charge-generating substance, pigment 1 of exemplified (78) [L part, butyral resin (trade name: 778M-2, tl
1 ffi (manufactured by I Suikagaku Co., Ltd.) and 30 fi parts of isopropyl alcohol were dispersed in a ball mill for 4 hours, and this dispersion was applied onto the previous subbing layer by dip coating.
A charge generation layer was formed by dry bombing. This film thickness is 0.3 pL
Met.

Next, 1 part by weight of the substance of fluorene compound example (22),
1 part by weight of polysulfone (P-1700, manufactured by UCC),
Mix chlorobenzene Gffi and stir with a stirrer,
Dissolved. This liquid was applied onto the previous charge generation layer by a dip coating method and dried to form a charge transport layer. The film thickness was 121L.

A corona discharge of 15 KV was applied to the photoreceptor thus prepared.

The surface potential (initial potential Vo) at this time was measured. Furthermore, the surface potential of this photoreceptor was measured after it was left in a dark place for 5 seconds.

Sensitivity was evaluated by measuring the amount of exposure (El/2J/cm2) required to attenuate the potential VK to 1/2 after dark decay. At this time, a gallium/aluminum/arsenic ternary semiconductor laser (output 5 mW, oscillation wavelength 780 nm) was used as a light source. Show the results.

Vo knee 690V potential retention rate (Vi/V6 x 100): 96
%El/2: 2.8ILJ/cm Second, the photoreceptor of a laser beam printer (manufactured by Canon ■, LBP-LX), which is an electrophotographic printer using a reverse development method and equipped with the same semiconductor laser as described above, was subjected to the photoreceptor of the present invention. An actual image formation test was conducted under the conditions shown below.

Surface potential knee after primary charging: 700 V, surface potential knee after image exposure: 150 V (exposure amount: 1.2% J/cm2), transfer potential: +700 V, developer polarity: negative polarity, process speed: 50 mm/sec.

Development conditions (development bias) knee 450V, image exposure scan method: image scan, - exposure before next charging: 50 um
Full red exposure of x, sec.

Image formation was performed by line scanning a laser beam in accordance with character signals and image signals.

Good prints of both text and images were obtained.

Example 18 3 g of 4-(4-dimethylaminophenyl)-2,6-cyphenylthiavirylium perchlorate and 5 g of the substance of the fluorenone compound example (53) were added to polyester (same as above) in toluene-dioxane ( (50:50) solution was mixed with 100 mL of solution and dispersed in a ball mill for 6 hours.

This dispersion was applied onto an aluminum sheet using a Meyer bar so that the film thickness after drying was 15 JL.

The electrophotographic properties of the photoreceptor thus prepared were measured in the same manner as in Example 1. The results are shown below.

vo Knee 691V, V, Knee 682VEl/2:
2.14JLux, sea initial V, knee 690V, VL, knee 131V VD after 50,000 sheets durability knee 681V, 'VL, knee 159V Example 1
9 Place a casein ammonia aqueous solution (casein 1) on an aluminum plate.
1.2g, 28% ammonia water 1g, water 222 mal
) was coated with Mayer Par and dried to form an adhesive layer with a film thickness of IIL.

Next, 5 g of the disazo pigment of charge generating substance example (16) and 2 g of butyral resin (butyralization degree 63%) were dispersed together with a solution dissolved in 95 mJL of ethanol, and then coated on the contact M layer, and after drying, the film A charge generation layer having a thickness of 0.4 mm was formed.

Next, a charge generation layer was prepared by dissolving 5 g of the fluorene compound example (55) and 5 g of poly-4,4° dioxydiphenyl-2,2-propane carbonate (viscosity average molecular weight 30,000) in 150 mJL of dichloromethane. An electrophotographic photoreceptor was prepared by coating and drying on top to form a charge transport layer having a thickness of 111 L.

The electrophotographic properties of this photoreceptor were measured in the same manner as in Example 1. Show the results.

Vo knee 889V, Vl knee 680Vel/2:
2.091ux, sec Initial Vo: -688V, VL: -1
After durability of 30V 50,000 sheets VD knee 678V, VL knee 156V Example 20 A 0.2 mm thick molybdenum plate (substrate) whose surface was cleaned was fixed at a predetermined position in a glow discharge deposition tank. Next, the inside of the tank was evacuated. The vacuum level was approximately 5×10″6 torr.

Thereafter, the input voltage of the heater was increased to stabilize the molybdenum substrate temperature at 150°C. After that, hydrogen gas and silane gas (15% by volume relative to hydrogen gas) were introduced into the tank, and 5MHz high-frequency power was applied to the zero-order induction coil, which was stabilized at 0.5 torr by adjusting the gas flow rate and the main valve of the deposition tank. A glow discharge is generated inside the coil inside the tank and the power is 30W.
The input power was set to . An amorphous silicon film was grown on the substrate under the above conditions, and after the same conditions were maintained until the film thickness reached 21L, glow discharge was stopped. After that, turn off the heater and high frequency power supply, wait until the substrate temperature reaches 100℃, close the hydrogen gas and silane gas outflow valves,
Once the inside of the tank was lowered to below to-5 torr, the pressure was returned to atmospheric pressure and the substrate was taken out.

Next, a charge transport layer was formed on this amorphous silicon layer in the same manner as in Example 1 except that the fluorenone compound was used.

The photoreceptor created in this way was installed in a charging exposure experiment equipment,
It was corona charged at -6 KV and immediately irradiated with a light image. The light image was illuminated through a transmission type test chart using a tungsten lamp light source. Immediately thereafter, a positively charged developer (including toner and carrier) was cascaded onto the photoreceptor surface to obtain a good toner image on the photoreceptor surface.

Example 21 3 g of 4-(4-dimethylaminophenyl)-2,6-siphenylthiapyrylium perchlorate and poly(4,4
'-isopropylidene diphenylene carbonate) 3g
After sufficiently dissolving and in 200 mal of dichloromethane,
100 mu of toluene was added to precipitate the eutectic complex. After separating this precipitate, dichloromethane was added to dissolve it again, and then 100 mJl of n-hexane was added to this solution to obtain a precipitate of a eutectic complex.

5 g of this eutectic complex was added to 95 mfL of a methanol solution containing 2 g of polyvinyl butyral and dispersed in a ball mill for 6 hours. After drying, this dispersion was applied onto an aluminum plate having a casein layer using a Mayer bar to a film thickness of 0.4% to form a charge generation layer.

Next, a charge transport layer was formed on the charge generation layer in the same manner as in Example 1 except that the material of Fluorene Compound Example (25) was used. The electrophotographic properties of the thus prepared photoreceptor were measured in the same manner as in Example 1.

The results are shown below.

vo knee 688V, vi knee 670VEt/2
: 1.98JLux, sea initial VD knee 685V, VL knee 121V after 50,000 sheet durability Vl, knee 677V, v, knee 151V Example 22 5 g of the same eutectic complex used in Example 21 and the above fluorene system 150 m 4 of tetrahydrofuran solution containing 5 g of compound example (43) and polyester (same as above)
1 and thoroughly mixed and stirred.

This liquid was applied onto an aluminum sheet using a Mayer bar so that the film thickness after drying was 15 tons.

The electrophotographic properties of this photoreceptor were measured in the same manner as in Example 1. Show the results.

vo knee 691V, V, knee 680VE 1 /
2: 2, 341 u X, S e C first
Period Vll, Knee 680V, VL: 135V After 50,000 sheets durability Vtl Knee 678V, VL Knee 159V [Effects of the Invention] The electrophotographic photoreceptor of the present invention has high sensitivity and high sensitivity by using a specific compound as a charge transport material. It has the remarkable effect of improving light and potential stability during durability and being applicable to a wide range of fields of electrophotography.

Claims (1)

[Claims] (1) An electrophotographic photoreceptor characterized by having a layer containing a fluorene compound represented by the following general formula. General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ In the formula, R_1, R_2, R_3, R_4, R_5 and R
_6 represents an alkyl group, aralkyl group, aryl group, or heterocyclic group which may have a substituent, and R_1 and R_
2, R_3 and R_4 each represent a residue that forms a heterocycle with a nitrogen atom, and R_5 and R_6 are
One of them may be a hydrogen atom.