JPH075703A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain such an electrophotographic sensitive body that suppresses changes in surface potential or dark decay for repeated use and can obtain stable picture images by incorporating a specified compd. into a photoconductive layer formed on a conductive substrate. CONSTITUTION:The photoconductive layer formed on a conductive substrate contains cyclopentanone by 0.05-10.0wt.%. By this method, characteristics for repeated use can be largely improved. If the amt. of cyclopentanone is less than 0.05wt.%, the effect is not enough. If the amt. exceeds 10.0wt.%, electrification property decreases and the residual potential increases. The amt. is preferably in the range of 0.1-8.0wt.%. When a proper amt. of cyclopentanone is made to remain in the photoconductive layer by controlling the drying temp., it is preferable to control the drying temp. of the photoconductive layer at 70-160 deg.C, more preferably 80-130 deg.C in order to incorporate a proper amt. of cyclopentanone into the photoconductive layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member which has good sensitivity and dark decay characteristics and has little change in surface potential and dark decay when repeatedly used.

[0002]

2. Description of the Related Art As a conventional electrophotographic photosensitive member, selenium (S) of about 50 μm is formed on a conductive substrate such as aluminum.
e) There is a film formed by a vacuum evaporation method. However, this Se photoconductor has a problem that it has sensitivity only up to a wavelength of about 500 nm. Moreover, a Se layer of about 50 μm is formed on the conductive substrate, and further several μm is formed on this.
There is a photoconductor on which a selenium-tellurium (Se-Te) alloy layer is formed. This photoconductor has a higher Te content in the Se-Te alloy, but the spectral sensitivity extends to a longer wavelength,
As the amount of Te added increases, the surface charge retention property becomes poor, and there is a serious problem that it cannot be used as a photoconductor in practice.

A chlorocyan blue or squarylium acid derivative of about 1 μm is coated on an aluminum substrate to form a charge generation layer, and a mixture of a polyvinylcarbazole or pyrazoline derivative having a high insulation resistance and a polycarbonate resin is formed on the charge generation layer. There is a so-called laminated type photoconductor in which a charge transport layer is formed by coating with 10 to 20 μm, but in reality, this photoconductor does not have sensitivity to light of 700 nm or more.

In recent years, the above-mentioned drawbacks have been improved in this laminated type photoreceptor, that is, a semiconductor laser oscillation region of 800 nm.
Although many photoreceptors having front and rear sensitivities have been reported, most of them use a phthalocyanine pigment as a charge generating material, and polyvinylcarbazole or pyrazoline is used on the charge generating layer having a thickness of about 0.5 to 1 μm. A mixture of a derivative or hydrazone derivative and a polycarbonate resin or a polyester resin having a high insulation resistance is 10 to 20 μm.
The charge transport layer is formed by coating to form a laminated type photoreceptor.

The laminated photoreceptor has a wide selection range of materials used for forming the photosensitive layer, and has various electrophotographic characteristics such as charging characteristics, dark decay, sensitivity, residual potential, repetitive characteristics and printing durability.
Since a high-performance photoconductor can be provided by combining the best materials, such a photoconductor has been widely used.

However, although such a laminated photoreceptor has excellent mechanical durability, it cannot be said that there is no problem in electrostatic durability and repetitive characteristics, and in particular, the surface potential decreases as it is repeatedly used. However, there is a problem that the surface potential drops sharply during the time from charging to development, that is, dark decay increases.

In order to improve such repetitive characteristics, various attempts have been made in the past to add various additives such as antioxidants to improve the deterioration of characteristics. However, although some improvement was observed by adding such an additive, the sensitivity was sometimes lowered by this, and a satisfactory photoreceptor could not be obtained.

[0008]

SUMMARY OF THE INVENTION The present invention provides an electrophotographic photosensitive member which suppresses changes in surface potential and dark decay which occur in a laminated photosensitive member at the time of repetition and which can obtain a stable image.

[0009]

[Means for Solving the Problems]

In the present invention, the photoconductive layer formed on the conductive substrate contains 0.05 to 10.0% by weight of cyclopentanone.
The present invention relates to a photoconductor.

The present invention will be described in detail below. By including a certain amount of cyclopentanone in the photoconductive layer, the repeating characteristics are significantly improved.

Here, the content of cyclopentanone is set to 0.05 to 10.0% by weight with respect to the photoconductive layer, and the effect is sufficiently exhibited when the content is less than 0.05% by weight. On the other hand, on the other hand, if the content exceeds 10.0% by weight, the charging property is lowered and the residual potential is also increased. More preferably, the cyclopentanone content is in the range of 0.1 to 8.0% by weight.

As a method for incorporating cyclopentanone into the photoconductive layer, for example, when the photoconductive layer is prepared, cyclopentanone is used as a solvent, and the drying condition is adjusted so that an appropriate amount of cyclopentanone is photoconductive. It is allowed to remain in the layer, or cyclopentanone is not used at the time of producing the photoconductive layer, but an appropriate amount of cyclopentanone is contained in the photoconductive layer by a method such as a spray method or a vapor bath after the photoconductive layer is produced. And a method in which after removing cyclopentanone used in forming the photoconductive layer by drying, an appropriate amount of cyclopentanone is contained in the photoconductive layer.

Here, when the drying conditions are adjusted so that an appropriate amount of cyclopentanone remains in the photoconductive layer, the drying temperature is adjusted so that the photoconductive layer contains an appropriate amount of cyclopentanone. The temperature is preferably adjusted to 70 to 130 ° C, more preferably 80 to 120 ° C.

The amount of cyclopentanone remaining in the photoconductive layer can be quantified by measuring the amount of weight loss by thermal analysis. Specifically, 10 mg of the photosensitive layer was weighed, and the temperature was raised from room temperature to 150 ° C. immediately while flowing 200 ml / min of nitrogen gas, and then kept at the same temperature for 10 minutes to reduce the weight loss of the photoconductive layer. The weight reduction amount can be measured and quantified as the residual amount of cyclopentanone.

Further, by using gas chromatography, the amount of cyclopentanone remaining in the photoconductive layer can be quantified. Specifically, 30 mg of the photoconductive layer is weighed, immersed in a solvent such as acetone, methyl ethyl ketone, tetrahydrofuran, and ethanol, and the remaining solvent is extracted using ultrasonic waves. Then, toluene, benzene, hexane or the like is added to this as an internal standard substance, and it can be quantified by an internal standard method using gas chromatography.

The electrophotographic photoreceptor of the present invention comprises a photoconductive layer provided on a conductive substrate.

The photoconductive layer is a layer containing an organic photoconductive substance, and is a laminated type comprising a film of an organic photoconductive substance, a film containing an organic photoconductive substance and a binder, a charge generation layer and a charge transport layer. There is a film etc.

Examples of the organic photoconductive substance include:
The phthalocyanine composition described below can be used, and further known compounds can be used in combination. Also,
It is preferable to use at least a phthalocyanine composition and a charge-transporting substance together in the film of the organic photoconductive substance. In addition, it is preferable to use the following phthalocyanine composition and / or the organic pigment which generate | occur | produces an electric charge for the said charge generating layer, and a charge transporting substance is normally used for a charge transporting layer.

As the phthalocyanine composition, known ones can be used, but a mixed crystal of titanyl phthalocyanine and indium phthalocyanine chloride or a mixed crystal of a chlorinated derivative compound of titanyl phthalocyanine and indium phthalocyanine chloride is preferable because of high sensitivity. Such a phthalocyanine composition can be manufactured as follows.

18.4 g (0.144 mol) of phthalonitrile are added to 120 ml of α-chloronaphthalene, and then 4 ml (0.0364 mol) of titanium tetrachloride are added dropwise under a nitrogen atmosphere. After dripping, the temperature is raised and stirred with 200 to 220
After reacting at ℃ for 3 hours, hot filtration at 100 to 130 ℃, washed with α-chloronaphthalene, methanol.
Hydrolysis with 140 ml of deionized water (90 ° C, 1 hour)
Repeat this operation until the solution becomes neutral and wash with methanol. Next, the substrate is thoroughly washed with NMP at 100 ° C., and then with methanol. The compound thus obtained is heated and dried at 60 ° C. under vacuum to obtain titanyl phthalocyanine (yield 46%).

On the other hand, the method for synthesizing indium chloride phthalocyanine and a chlorinated derivative of indium phthalocyanine is described in Inorganic Chem.
istry 19 , 3131 (1980)] and JP-A-59-44054.

Indium phthalocyanine chloride can be produced, for example, as follows.

78.2 mmol of phthalonitrile and 15.8 mmol of indium trichloride were put into 100 ml of quinoline which had been distilled twice and deoxygenated, and the mixture was heated under reflux for 0.5 to 3 hours, then gradually cooled, and then cooled to 0 ° C. After filtration, the crystals are washed with methanol, toluene and acetone, and then at 110 ° C.
To dry.

The chlorinated derivative of indium phthalocyanine chloride can be produced, for example, as follows. Phthalonitrile (156 mmol) and indium trichloride (37.5 mmol) were mixed and heated at 300 ° C. and heated for 0.5 to 3 hours to obtain a crude product of monochloroindium chlorophthalocyanine, which was placed in a Soxhlet extractor. Wash with α-chloronaphthalene.

The composition ratio of the phthalocyanine composition comprising a mixed crystal of titanyl phthalocyanine and indium phthalocyanine chloride or a mixed crystal of a chlorinated derivative of titanyl phthalocyanine and indium phthalocyanine depends on electrophotographic characteristics such as chargeability, dark decay and sensitivity. To titanyl phthalocyanine content is preferably 20 to 95% by weight, more preferably 50 to 90% by weight, particularly preferably 65 to 90% by weight, and 75 to 90% by weight. Most preferably, it is in the range of%.

Mixed crystals of titanyl phthalocyanine and indium phthalocyanine chloride or mixed crystals of chlorinated derivatives of titanyl phthalocyanine and indium phthalocyanine chloride are prepared from a simple mixture of two phthalocyanines by acid pasting and solvent treatment as follows: be able to.

For example, a mixture 1 of two phthalocyanines
g was dissolved in 50 ml of concentrated sulfuric acid and stirred at room temperature, and this was added dropwise to 1 liter of ion-exchanged water cooled with ice water in about 1 hour, preferably 40 to 50 minutes, to cause reprecipitation. After standing overnight, the supernatant is removed by decantation, and the precipitate is collected by centrifugation. After that, the precipitate is repeatedly washed with ion-exchanged water as washing water until the pH after washing with washing water is 2 to 5 and the conductivity is 5 to 500 μS / cm. Then, after thoroughly washing with methanol, vacuum heating and drying at 60 ° C. give a powder.

If the pH exceeds 5, the desired mixed crystal cannot be obtained even if the following solvent treatment is carried out. On the other hand, if the pH is 2 or less, the photoreceptor prepared using the obtained mixed crystal is satisfactory. The desired electrophotographic characteristics cannot be obtained.

The powder thus obtained can be crystal-transformed by treating it with an organic solvent to obtain a highly sensitive phthalocyanine composition.

For example, 1 g of the powder obtained by the above method is put in 10 ml of N-methyl-2-pyrrolidone, toluene or xylene as an organic solvent, and heated and stirred (the above powder /
The solvent (weight ratio) is 1/1 to 1/100). The heating temperature is 50 ° C to 200 ° C, preferably 80 ° C to 150 ° C.
And the heating time is 1 hour to 10 hours, preferably 1 hour to 6 hours. After completion of heating and stirring, filtration, washing with methanol, and vacuum heating and drying at 60 ° C. can give 700 mg of crystals of the phthalocyanine composition. As the organic solvent used in this treatment, for example, methanol, ethanol,
Alcohols such as isopropanol and butanol, n-
Hexane, octane, alicyclic hydrocarbons such as cyclohexane, benzene, toluene, aromatic hydrocarbons such as xylene, tetrahydrofuran, dioxane, diethyl ether, ethylene glycol dimethyl ether, ethers such as ethylene glycol diethyl ether, acetate cellosolve, acetone, Ketones such as methyl ethyl ketone, cyclohexanone and isophorone, esters such as methyl acetate and ethyl acetate, dimethyl sulfoxide, dimethylformamide, phenol, cresol, anisole, nitrobenzene, acetophenone, benzyl alcohol, pyridine, N-methyl-2-pyrrolidone, quinoline , Non-chlorine organic solvents such as picoline, dichloromethane,
Examples thereof include chlorine-based organic solvents such as dichloroethane, trichloroethane, tetrachloroethane, carbon tetrachloride, chloroform, chloromethyloxirane, chlorobenzene and dichlorobenzene.

Of these, ketones, alcohols and non-chlorine organic solvents are preferable, and among these, N-methyl-2-pyrrolidone, pyridine, isopropanol, methyl ethyl ketone and diethyl ketone are preferable.

Other organic pigments which generate the electric charge include azoxybenzene type, disazo type, trisazo type,
Benzimidazole type, polycyclic quinone type, indigoid type, quinacridone type, perylene type, methine type, α type, β
Pigments known to generate electric charges such as metal-free or metal-type phthalocyanine-based pigments having various crystal structures such as γ-type, γ-type, δ-type, ε-type, and χ-type can be used.
These pigments are disclosed, for example, in JP-A-47-37543, JP-A-47-37544, and JP-A-47-18.
No. 543, No. 47-18544, No. 48-43942, No. 48-70538, No. 49-1231, No. 49-105.
No. 536, JP-A-50-75214, JP-A-53-44028, and JP-A-54-17732.

Further, τ, τ ′, η and η ′ type metal-free phthalocyanines disclosed in JP-A-58-182640 and European Patent Publication No. 92,255 can also be used. In addition to these substances, any organic application that generates a charge carrier upon irradiation with light can be used.

As the charge-transporting substance, polymer compounds such as poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylindroquinoxaline, polyvinylbenzothiophene, polyvinylanthracene, polyvinylacridine are used. , Polyvinylpyrazoline, etc., and low molecular compounds include fluorenone, fluorene, 2,7-dinitro-9-fluorenone, 4H-indeno (1,2,6)
Thiofen-4-one, 3,7-dinitro-dibenzothiophen-5-oxide, 1-bromopyrene, 2-phenylpyrene, carbazole, N-ethylcarbazole, 3-phenylcarbazole, 3- (N-methyl-N).
-Phenylhydrazone) methyl-9-ethylcarbazole, 2-phenylindole, 2-phenylnaphthalene, oxadiazole, 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole, 1-
Phenyl-3- (4-diethylaminostyryl) -5-
(4-Diethylaminostyryl) -5- (4-diethylaminophenyl) pyrazoline, 1-phenyl-3- (p
-Diethylaminophenyl) pyrazolin, p- (dimethylamino) -stilbene, 2- (4-dipropylaminophenyl) -4- (4-dimethylaminophenyl) -5
-(2-chlorophenyl) -1,3-oxazole, 2
-(4-Dimethylaminophenyl) -4- (4-dimethylaminophenyl) -5- (2-fluorophenyl)-
1,3-oxazole, 2- (4-diethylaminophenyl) -4- (4-dimethylaminophenyl) -5-
(2-fluorophenyl) -1,3-oxazole, 2
-(4-Dipropylaminophenyl) -4- (4-dimethylaminophenyl) -5- (2-fluorophenyl)
Examples include -1,3-oxazole, imidazole, chrysene, tetraphene, aclidene, triphenylamine, benzidine, and their derivatives. As the charge-transporting substance, a benzidine derivative represented by the following general formula (I) is particularly preferable.

[0036]

[Chemical 1] (R ₁ and R ₂ each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, a fluoroalkyl group or a fluoroalkoxy group, and at least one of R ₁ and R ₂ is fluoroalkyl. A group or a fluoroalkoxy group, and each R ₃ independently represents
A hydrogen atom or an alkyl group, and Ar ₁ and Ar ₂ each independently represent an aryl group)

In the general formula (I), examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group and a tert-butyl group. As the alkoxy group, a methoxy group, an ethoxy group,
Examples include n-propoxy group and iso-propoxy group. Examples of the aryl group include a phenyl group, a tolyl group, a biphenyl group, a terphenyl group and a naphthyl group. Examples of the fluoroalkyl group include a trifluoromethyl group, a trifluoroethyl group, a heptafluoropropyl group and the like. As the fluoroorcoxy group, a trifluoromethoxy group, a 2,3-difluoroethoxy group,
2,2,2-trifluoroethoxy group, 1H, 1H-pentafluoropropoxy group, hexafluoro-iso-propoxy group, 1H, 1H-pentafluorobutoxy group,
2,2,3,4,4,4-hexafluorobutoxy group,
Examples thereof include fluoroalkoxy groups such as 4,4,4-trifluorobutoxy group. Examples of the benzidine derivative represented by the general formula (I) include the following No. 1-No.
6 and the like.

[0038]

[Chemical 2]

[Chemical 3]

Next, the electrophotographic photosensitive member will be described.

The above-mentioned phthalocyanine composition and an organic pigment which generates an electric charge used as necessary (both are the former)
And a charge-transporting substance (the latter) are used as a mixture (when a single-layer photoconductive layer is formed), the latter / the former is in a weight ratio of 10/1 to 2/1. It is preferable to mix them. At this time, the binder is 0 to 500% by weight, particularly 30 to 500% by weight based on the total amount of these compounds (the former + the latter).
It is preferably used in the range of weight%. When using these binders, additives such as a plasticizer, a fluidity-imparting agent, and a pinhole suppressor can be added, if necessary.

When a laminated photoconductive layer comprising a charge generating layer and a charge transporting layer is formed, the charge generating layer contains the above phthalocyanine composition and, if necessary, an organic pigment which generates a charge, The agent may be contained in an amount of 500% by weight or less based on the total amount of the phthalocyanine composition and the organic pigment, and the above-mentioned additive is added in an amount of 5% by weight or less based on the total amount of the phthalocyanine composition and the organic pigment. You may. Further, the charge transport layer may contain the above-mentioned charge transport material, and may further contain a binder in an amount of 500% by weight or less based on the charge transport material. When the charge transporting substance is a low molecular weight compound, it is preferable that the binder is contained in an amount of 50% by weight or more based on the compound.

Binders that can be used in all of the above cases include silicone resin, polybutyral resin, polyamide resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, polyacrylic resin, polystyrene resin, styrene- Butadiene copolymer, polymethyl methacrylate resin, polyvinyl chloride, ethylene-vinyl acetate copolymer, vinyl chloride-
Examples thereof include vinyl acetate copolymer, polyacrylamide resin, polyvinyl carbazole, polyvinyl pyrazoline, polyvinyl pyrene and the like. Further, a thermosetting resin or a photocurable resin that is crosslinked by heat and / or light can also be used.

In any case, there is no particular limitation as long as it is an insulating resin capable of forming a coating film in a normal state and a resin which is cured by heat and / or light to form a coating film.

Examples of the plasticizer as the above-mentioned additive include halogenated paraffin, dimethylnaphthalene, dibutyl phthalate, and the like, and as the fluidity-imparting agent, Modaflow (manufactured by Monsanto Chemical Co.), Acronal 4F (manufactured by Basuf Co.) and the like. As the pinhole inhibitor,
Examples thereof include benzoin and dimethyl phthalate. These may be appropriately selected and used, and the amount thereof may be appropriately determined.

In the electrophotographic photosensitive member having a photoconductive layer formed on a conductive substrate, the thickness of the photoconductive layer is preferably 5 to 50 μm. When the laminated type of the charge generation layer and the charge transport layer is used as the photoconductive layer, the charge generation layer is preferably 0.00
The thickness is 1 to 10 μm, particularly preferably 0.2 to 5 μm. If it is less than 0.001 μm, it is difficult to uniformly form the charge generation layer, and if it exceeds 10 μm, the electrophotographic properties tend to deteriorate. The thickness of the charge transport layer is preferably 5 to 50 μm, particularly preferably 8 to 25 μm. If the thickness is less than 5 μm, the initial potential becomes low, and
If it exceeds μm, the sensitivity tends to decrease.

To form a photoconductive layer on a conductive substrate, a method of depositing an organic photoconductive substance on the conductive substrate, an organic photoconductive substance and, if necessary, other components such as toluene and xylene are used. Aromatic solvents, halogenated hydrocarbon solvents such as methylene chloride and carbon tetrachloride, alcohol solvents such as methanol, ethanol, propanol, etc. that are uniformly dissolved or dispersed and coated on a conductive substrate and dried. There is. As a coating method, a spin coating method, a dipping method or the like can be adopted. When the charge generation layer and the charge transport layer are formed in the same manner, either of the charge generation layer and the charge transport layer may be an upper layer, and the charge generation layer may be a two-layer charge transport layer. It may be sandwiched.

When the phthalocyanine composition is applied by spin coating, a coating solution obtained by dispersing the phthalocyanine composition in a halogenated solvent such as chloroform or toluene or a nonpolar solvent is used and the number of revolutions is 500 to 400.
Spin coating at 0 rpm is preferable, and when applying by a dipping method, the phthalocyanine composition is applied to an organic solvent such as methanol, dimethylformamide, chloroform, methylene chloride or 1,2-dichloroethane with a ball mill or ultrasonic wave. It is preferable to immerse the conductive substrate in the coating liquid that has been dispersed.

The electrophotographic photoreceptor may have a thin adhesive layer or a barrier layer immediately above the conductive substrate, or may have a protective layer on the surface.

[0049]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

Production Example 1 1 g of a phthalocyanine mixture consisting of 0.75 g of titanyl phthalocyanine and 0.25 g of indium phthalocyanine chloride was dissolved in 50 ml of sulfuric acid, stirred for 30 minutes at room temperature, and then added to 1 liter of ion-exchanged water cooled with ice water.
The solution was dropped in about 40 minutes and reprecipitated. Further, the mixture was stirred under cooling for 1 hour and then left overnight. After removing the supernatant liquid by decantation, the precipitate was separated by centrifugation to obtain 700 mg of precipitate. As the first washing, 120 ml of ion-exchanged water as washing water was added to 700 mg of the precipitate and stirred, and then the precipitate and the washing water were separated and removed by centrifugation.
The same washing operation was performed 5 times in succession. The pH and conductivity of the wash water separated and removed in the sixth operation (that is, the wash water after washing) were measured (23 ° C.). Model PH51 manufactured by Yokogawa Electric Corporation was used for the measurement of pH. Further, the conductivity is measured by model SC-17 manufactured by Shibata Scientific Instruments Co., Ltd.
A was used. The pH of the wash water is 3.3 and the conductivity is
It was 65.1 μS / cm. Then, it was washed 3 times with 60 ml of methanol and dried under vacuum at 60 ° C. for 4 hours. Next, 1 g of this vacuum dried product was added to 10 ml of isopropyl alcohol.
The mixture was heated and stirred at 90 ° C for 8 hours, filtered, washed with methanol, and vacuum-dried at 60 ° C for 4 hours, and the Bragg angle (2θ ± 0.2 °) was 7.5 degrees, 22.5 degrees, 24.3
Phthalocyanine crystals having major diffraction peaks at 25.3 and 28.6 degrees were obtained. The X-ray diffraction spectrum of this crystal is shown in FIG.

Production Example 2 Similarly, to 1 g of the above vacuum dried product, 9.0 g of ion-exchanged water and 86 g of toluene were added, and the mixture was heated and stirred at 60 ° C. for 8 hours,
After filtration, it was washed with methanol and vacuum-dried at 60 ° C. for 4 hours, and the Bragg angle (2θ ± 0.2 degrees) was 7.5 degrees, 2
Phthalocyanine crystals having major diffraction peaks at 4.2 degrees and 27.3 degrees were obtained. The X-ray diffraction spectrum of this crystal is shown in FIG.

Example 1 1.5 g of phthalocyanine produced in Production Example 1 and polyvinyl butyral resin S-REC BL-S (manufactured by Sekisui Chemical Co., Ltd.)
0.9 g, melamine resin ML351W (manufactured by Hitachi Chemical Co., Ltd.) 0.1 g, ethyl cellosolve 49 g and tetrahydrofuran 49 g were mixed and dispersed by a ball mill. The obtained dispersion liquid is applied onto an aluminum plate (conductive substrate 100 mm × 100 mm × 0.1 mm) by a dipping method, and the temperature is 120 ° C.
And dried for 1 hour to form a charge generation layer having a thickness of 0.5 μm. 1.5 g of the charge-transporting substance (No. 1) described above,
Polycarbonate resin Lexan 141 (manufactured by GE) 1.
The coating liquid obtained by blending 5 g of tetrahydrofuran, 12.4 g of tetrahydrofuran and 3.1 g of cyclopentanone was coated on the above substrate by the dipping method, and the content of cyclohexanone was about 0.2% by weight at 120 ° C. While being controlled as above, this was dried to form a charge transport layer having a thickness of 20 μm.
Electrophotographic characteristics (sensitivity, residual potential, dark decay rate, photoresponsiveness)
Was evaluated by Cynthia 30HC (manufactured by Gentech). The photoreceptor was charged to -650 V by the corona charging method, and monochromatic light of 780 nm was exposed on the photoreceptor of 50 mS to measure various characteristics. The definitions of the above properties are as follows. The sensitivity (E ₅₀ ) is the irradiation energy amount of monochromatic light of 780 nm required to halve the initial charging potential of −650 V after 0.2 seconds of exposure, and the residual potential (Vr) is 20 mJ / m ^{2 of the} same wavelength. Exposure of monochromatic light of 50 ms for 0.2
It is the potential remaining on the surface of the photoconductor after a second. Dark decay rate (DD
R) is (V ₁ / V) using the initial charging potential of the photoconductor of −650 V and the surface potential V ₁ (−V) after the initial charging and left in a dark place for 1 second.
650) × 100. The photoresponsiveness (T _1/2 ) is
It was defined as the time (sec) required to halve the initial charging potential of -650 V by exposing monochromatic light of 20 mJ / m ^{2 having} a wavelength of 780 nm for 50 ms. In addition, the repeatability is
The exposure was evaluated by the ratio of the charging potential V ₁₀₀₀ after repeating 1000 times to the initial charging potential −650 V (V ₀ retention rate), and the dark decay retention rate (DDR retention rate) evaluated by the same method. In addition, the image quality is evaluated by an image evaluation machine (negative charging,
Image densities of fogging, black spots, white spots, and black background were evaluated using the reverse development method). The surface potential was -700V and the bias potential was -600V. The image density of the black background was evaluated by a Macbeth reflection densitometer (manufactured by A division of Kollmergen Corporation). The results are shown in Table 1.

Example 2 The phthalocyanine obtained in Production Example 2 in Example 1,
No. 1 as a charge transporting substance. 2 and the drying temperature is 100
℃, the content of cyclopentanone is about 3.0% by weight
An electrophotographic photosensitive member was manufactured in accordance with Example 1 except that the film was dried so that the characteristics were evaluated. The results are shown in Table 1.

Example 3 In Example 1, τ-type metal-free phthalocyanine (manufactured by Toyo Ink Mfg. Co., Ltd.), I-56 as a charge transporting substance, and a weight ratio of tetrahydrofuran to cyclopentanone as a solvent for a coating liquid for a charge transporting layer A 1: 1 mixed solvent was used and the drying temperature was 80 ° C., and the cyclopentanone content was about 8.
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that it was dried to 0% by weight, and its characteristics were evaluated. The results are shown in Table 1.

Comparative Example 1 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the drying temperature was 140 ° C. and the cyclopentanone content was about 0.01% by weight. Then, the characteristics were evaluated. The results are shown in Table 1.

Comparative Example 2 An electrophotographic photosensitive member was produced in the same manner as in Example 2 except that the drying temperature was 50 ° C. and the cyclopentanone content was about 12.0% by weight. Then, the characteristics were evaluated. The results are shown in Table 1.

Comparative Example 3 An electrophotographic photosensitive member was produced in the same manner as in Example 3 except that the solvent of the charge transport layer coating solution was replaced by tetrahydrofuran (THF), and the characteristics were evaluated. The results are shown in Table 1.

[0058]

[Table 1]

[0059]

In the electrophotographic photosensitive member according to the present invention, 0.05 to 10.0% by weight of cyclopentanone is contained in the photosensitive layer formed on the conductive substrate. The holding ability of the charging potential and the dark decay is stable, a good image is obtained, and the photoreceptor can be used stably for a long period of time without impairing its electrophotographic characteristics.

[Brief description of drawings]

FIG. 1 is an X-ray diffraction diagram of phthalocyanine produced according to Production Example 1.

FIG. 2 is an X-ray diffraction diagram of phthalocyanine produced by Production Example 2.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Megumi Matsui 4-13-1, Higashimachi, Hitachi City, Ibaraki Prefecture Ibaraki Research Laboratory, Hitachi Chemical Co., Ltd.

Claims (2)

[Claims] 1. A photoconductive layer formed on a conductive substrate,
A photoreceptor containing 0.05 to 10.0% by weight of cyclopentanone. 2. The photoconductor according to claim 1, wherein the drying temperature of the photoconductive layer is 70 to 130 ° C.