JPH09120166A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoreceptor having superior repetitive characteristics, a long service life and high stability as well as superior performance (high γ) to digital light input by dispersing titanyl phthalocyanine having a specified crystal form in polycarbonate resin contg. specified structural units. SOLUTION: This photoreceptor having a threshold in its light attenuation curve obtained by dispersing titanyl phthalocyanine having peaks of the Bragg angles (2θ±0.2 deg.) at 9.5 deg., 24.1 deg. and 27.3 deg. in its X-ray diffraction spectrum in polycarbonate resin contg. structural units represented by the formula, wherein R is 1-6C alkyl, alkoxy or phenyl, (n) is 0-6, each of X<1> and X<2> is H, halogen or 1-6C alkyl and each of (l) and 9(m) is 0-4.

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 suitable for digital electrophotography used in electrophotography. Specifically, an electrophotographic photoconductor (a photoconductor having a high γ value) that has a threshold value in the light attenuation curve and has a small change in exposure energy that causes a transition from a high surface potential to a low surface potential.
It is about. In the present invention, “having a threshold value in the light attenuation curve” means the following. That is, in the light attenuation curve, the initial potential immediately after charging is V ₀ (V) and the residual potential is 50 μJ /
When the surface potential upon irradiation with light of cm ² is V _r (V), the difference between the two is ΔV (V ₀ −V _r ). At this time,
As 95% surface potential V ₉₅ , residual potential is ΔV 95
Surface potential with% value added (V ₉₅ = ΔV × 0.95 + V _r ).
Is taken as V ₅ "5% surface potential" and the residual potential is ΔV.
Surface potential (V ₅ = ΔV × 0.05 + V
_r )) and obtain the exposure energies giving V ₉₅ and V ₅ as “95% exposure energy” E ₉₅ and “5% exposure energy” E ₅ , respectively, and the value of E ₅ / E ₉₅ is 5 or less. Shall mean.

[0002]

2. Description of the Related Art Electrophotographic methods such as the Carlson method have been developed with a focus on rendering an original image in an analog manner. Therefore, in order to faithfully reproduce the brightness of the input light as the brightness of the toner image, the photoconductor used therein may have a characteristic that a photocurrent flows linearly similar to (the logarithmic value of) the input light amount. I have been asked. Therefore, it has been a principle to select a photosensitizer having such characteristics (low γ characteristics) as a material for the photoconductor. Therefore, it starts from a material close to a simple photoconductor in the early stage of electrophotography, and is similar to a photosensitive layer in an amorphous state of selenium (Se), an amorphous layer of silicon (Si), and an amorphous layer of Se. The prepared ZnO tie layer or the like has been used as a photoreceptor. Furthermore, in recent years, so-called function-separated photosensitive layers using organic semiconductors have been developed until they are used as photoreceptors. However, recently, the combination of electrophotographic technology and computer / communication has led to a rapid shift in the printer and facsimile systems to the electrophotographic recording system.In addition, even with ordinary copy machines, reversal, clipping, whiteout, etc. It is becoming a method that enables image processing. Therefore, it is desired to change the recording method of electrophotography from the conventional analog recording format for PPC to the digital recording format.

Further, as an input light source used in the digital recording system, there are a gas laser such as an Ar laser and a He-Ne laser, a semiconductor laser, a shutter array such as a liquid crystal, an LED and an EL array. Among them, semiconductor lasers are currently the mainstream because they can be downsized and reduced in cost, and a photosensitizer having high sensitivity in the near infrared region, which is the oscillation wavelength of semiconductor lasers, is required.

Further, as described above, the photoconductor used in the traditional electrophotographic method based on the analog concept is
It has a low γ characteristic, and due to its characteristics, it is suitable for electronic photography, such as a printer for outputting data from a computer, or a digital copy for digitally processing an image, in which an input digital optical signal must be rendered as a digital image. Not suitable. That is, even the deterioration of the digital signal in the signal path from the computer or image processing device to the electrophotographic device, or the aberration caused by the optical system for converging the writing light beam or forming the original image. However, the photoconductors using these photosensitizers faithfully depict the original digital images.
Therefore, it is strongly desired to provide a digital photoconductor having high sensitivity and high γ characteristics which can be used in this field. Under such circumstances, the concept of a digital photoconductor is disclosed in Japanese Patent Application Laid-Open No. 1-169454.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the present situation, and has excellent performance (high γ characteristic) with respect to digital optical input, and also has excellent repeatability, long life and high stability. Another object of the present invention is to provide an electrophotographic photosensitive member.

[0006]

As a result of intensive studies for solving the above-mentioned problems, the present invention has revealed that titanyl phthalocyanine having a specific crystal form is a specific binder resin, that is, the following general formula [I ] By dispersing in a polycarbonate resin containing a specific structural unit represented by, excellent performance for digital light input (having a threshold,
In addition to exhibiting high γ characteristics), it has been found that it has excellent repeatability and has a long life and high stability, and completed the photoreceptor of the present invention.

That is, according to the present invention, in an electrophotographic photosensitive member comprising phthalocyanine dispersed in a binder resin, phthalocyanine is titanyl phthalocyanine having a specific crystal form, and the binder resin is a polycarbonate containing a specific structural unit. An electrophotographic photosensitive member characterized by being a resin, which has a threshold value in a light decay curve and has a small change in exposure energy for transition from a high surface potential to a low surface potential (high γ value photosensitive member) Is.

[0008]

Embedded image

(In the formula, R is an alkyl group having 1 to 6 carbon atoms or a phenyl group, and n is 0 to 6.
X ¹ and X ² are the same or independently a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms, and l and m are the same or independently 0 to 4. Hereinafter, the present invention will be described in detail.

<1> Titanyl phthalocyanine The titanyl phthalocyanine used in the present invention is CuX.
In the X-ray diffraction spectrum of α rays, the black angle (2θ ±
0.2 °) has peaks at 9.5 °, 24.1 °, and 27.3 °. Usually, the intensity of the diffraction peak at 27.3 ° is the strongest. The synthesis method of titanyl phthalocyanine is described in Moser and Thomas's “Phthalocyanine Compound” (MOSER and THOMAS, “Pht.
halocyane compounds ”) and other known methods, for example, a method of heating and melting o-phthalonitrile and titanium tetrachloride or heating in the presence of an organic solvent such as α-chloronaphthalene. , 1,3-diiminoisoindoline and tetrabutoxytitanium can be obtained in a good yield by a method of heating them with an organic solvent such as N-methylpyrrolidone.The titanyl phthalocyanine thus synthesized contains a chlorine-substituted phthalocyanine. As a method for producing titanyl phthalocyanine of the present invention, for example, titanyl phthalocyanine is mechanically ground, and an organic solvent is added to a suspension obtained by dispersing in water, followed by treatment.
Although it can be produced by the method described in Japanese Patent Publication No. 8 and the like, it is not limited to this method, and even if it is produced by another production method, it can be used if it belongs to the same crystal form crystallographically. It is possible.

<2> Polycarbonate Resin The polycarbonate resin used in the present invention is a polycarbonate resin containing a specific structural unit represented by the following general formula [I].

[0012]

Embedded image

(Wherein R is an alkyl group, an alkoxy group or a phenyl group having 1 to 6 carbon atoms, and n is 0 to 6).
It is. X ¹ and X ² are the same or independently a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms, and l and m are the same or independently 0 to 4. )

The specific structural unit contained in the polycarbonate resin used in the present invention will be specifically described. R in the general formula [I] is an alkyl group having 1 to 6 carbon atoms, an alkoxy group or a phenyl group. As examples of these, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, pentyl group, hexyl group, cyclohexyl group, methoxy group, It is an ethoxy group, a propoxy group or a phenyl group, and the hydrogen atom of these groups may be substituted with a halogen atom, another alkyl group, an alkoxy group or a phenyl group. In addition, X ¹ and X ² are the same or independently a hydrogen atom, a halogen atom and an alkyl group having 1 to 6 carbon atoms, examples of which include a fluorine atom, a chlorine atom, a bromine atom, a methyl group, Ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group,
A pentyl group, a hexyl group, a cyclohexyl group, a methoxy group, an ethoxy group, a propoxy group, a phenyl group, even if the hydrogen atom of these groups is substituted with a halogen atom, another alkyl group, an alkoxy group or a phenyl group. good.

The method for producing the polycarbonate resin used in the present invention includes a method of polymerizing by transesterification of an aromatic dihydroxy compound and a carbonic acid derivative (transesterification method, melt polymerization method), and a method of removing an aromatic dihydroxy compound and phosgene. There are a method of performing polymerization in a solution or an interface in the presence of an acid agent (phosgene method), a method of ring-opening polymerization of a cyclic oligocarbonate, and the like. Various aromatic dihydroxy compounds are used in the polymerization of polycarbonate resin,
In the present invention, an aromatic dihydroxy compound having a specific structure represented by the following structural formula [II] is used.

[0016]

Embedded image

(Wherein R is an alkyl group, an alkoxy group or a phenyl group having 1 to 6 carbon atoms, and n is 0 to 6).
It is. X ¹ and X ² are the same or independently a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms, and l and m are the same or independently 0 to 4. )

As the raw material monomer of the polycarbonate resin used in the present invention, 1,1-bis (4-hydroxyphenyl) -cyclohexane, 1,1-bis (4-hydroxyphenyl) -4-methyl-cyclohexane,
1,1-bis (4-hydroxyphenyl) -3-methyl-cyclohexane, 1,1-bis (4-hydroxyphenyl) -2-methyl-cyclohexane, 1,1-bis (4-hydroxyphenyl) -4, 4-dimethyl-cyclohexane, 1,1-bis (4-hydroxyphenyl)
-3,3-Dimethyl-cyclohexane, 1,1-bis (4-hydroxyphenyl) -2,2-dimethyl-cyclohexane, 1,1-bis (4-hydroxyphenyl)
-2,4-Dimethyl-cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,4-dimethyl-cyclohexane, 1,1-bis (4-hydroxyphenyl)
-2,5-Dimethyl-cyclohexane, 1,1-bis (4-hydroxyphenyl) -4-ethyl-cyclohexane, 1,1-bis (4-hydroxyphenyl) -4-
Propyl-cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethyl-cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,
3,5-triethyl-cyclohexane, 1,1-bis (4-hydroxy-3-methyl-phenyl) -cyclohexane, 1,1-bis (4-hydroxy-3,5-dimethyl-phenyl) -cyclohexane, 1, 1-bis (4
-Hydroxy-3-ethyl-phenyl) -cyclohexane, 1,1-bis (4-hydroxy-3-chloro-phenyl) -cyclohexane, 1,1-bis (4-hydroxyphenyl) -4-ethyl-cyclohexane, 1 , 1-
Bis (4-hydroxy-3-methyl-phenyl) -3,
3,5-trimethyl-cyclohexane, 1,1-bis (4-hydroxy-3-chloro-phenyl) -3,3,3
5-trimethyl-cyclohexane etc. are mentioned. Further, the polycarbonate resin of the present invention may be a copolymer of the above monomer and another dihydroxy compound. Examples of other dihydroxy compounds include 2,2-bis (4
-Hydroxyphenyl) -propane, bis (4-hydroxyphenyl) -methane, bis (4-hydroxyphenyl) -sulfone, 2,2-bis (4-hydroxy-3)
-Methyl-phenyl) -propane, 2,2-bis (4-
Hydroxy-3,5-dimethyl-phenyl) -propane, 2,2-bis (4-hydroxy-3-bromo-phenyl) -propane, 2,2-bis (4-hydroxy-)
3,5-dibromo-phenyl) -propane, di (4-hydroxyphenyl) -methyl-phenyl-methane, 2,
Bisphenols such as 2-bis (4-hydroxyphenyl) -butane, 4,4′-dihydroxybiphenyl,
4,4'-dihydroxy-3,3'-dimethyl-biphenyl, 4,4'-dihydroxy-3,3 ', 5,5'-
Biphenyls such as tetramethyl-biphenyl, aromatic dihydroxy compounds such as hydroquinone and dihydroxynaphthalene, and the like can be mentioned. The composition ratio of copolymerizing these other monomers is 0 to 90 mol%. When the content of the other monomer increases, the high γ characteristic will not be exhibited. When the copolymer is used, it may be a random polycarbonate or a block copolycarbonate.

The method for producing the polycarbonate resin used in the present invention by the phosgene method (interfacial polymerization method) is such that methylene chloride, toluene and xylene are used as the organic solvent, and an alkaline aqueous solution is used as the deoxidizing agent. Polymerization is carried out by coexisting an organic solvent in an aqueous alkaline solution of the compound and blowing phosgene into the organic solvent. Phosgene is usually blown in an excess of about 20%, and
Tertiary amine, quaternary ammonium, phosphonium salts, etc. may be added to accelerate the polymerization reaction. The reaction temperature is 0 to 50 ° C, preferably 10 to 30 ° C. The reaction time varies depending on conditions such as temperature and catalyst, but is 30 minutes to 5 hours.

In the method for producing the polycarbonate resin used in the present invention by the transesterification method, an aromatic dihydroxy compound and an aromatic ester of carbonic acid are melt-polymerized in the presence of a base catalyst. As a catalyst for transesterification, basic metal oxides such as alkali metals, alkaline earth metals and zinc oxide, carbonates of various metals, acetates, hydrides, quaternary ammonium salts and basic metal salts such as phosphonium salts. Is used. Polymerization is carried out by gradually reducing the pressure between 200 and 350 ° C. Eventually 1mmHg
The reaction is terminated with the following high vacuum. The reaction time is temperature,
The time is 2 to 5 hours, though it varies depending on the conditions such as the catalyst.
Further, during polymerization, it should be carried out in an inert atmosphere of nitrogen, argon or the like in order to suppress abnormal reactions such as decomposition and crosslinking.

The polycarbonate resin used in the present invention preferably has a number average molecular weight of 3,000 to 500,000, more preferably 10,000 to 200,000.
The glass transition temperature is 20 to 300 ° C, more preferably 50 to 250 ° C. Such a polycarbonate resin may be obtained by polymerizing each of the above monomers by the above method, but a commercially available product may be used. Examples of commercially available products include "Upilon" manufactured by Mitsubishi Gas Chemical Co., Inc., APEC manufactured by Bayer Japan Co., Ltd., and the like.

<3> Electrophotographic Photoreceptor A photoreceptor suitable for digital electrophotography of the present invention can be obtained by providing a photosensitive layer having the above phthalocyanine dispersed in the above polycarbonate resin on a conductive substrate. That is, the phthalocyanine and the homopolymer or copolymer produced by the above-mentioned method are uniformly dispersed with a solvent and the like in a kneading disperser such as a ball mill and an attritor, and coated on a conductive support to form a single layer. The photosensitive layer may be formed of The mixing ratio of the phthalocyanine and the polycarbonate resin is about 1: 1 to 10 by weight, and the phthalocyanine and the polycarbonate resin are mixed with the solvent. Then, the mixed phthalocyanine and polycarbonate resin are applied to a metal such as aluminum ordinarily used for an electrophotographic photoreceptor, or a conductive support such as paper or plastic subjected to conductive treatment to form a photosensitive layer.

The solvent used for the coating liquid is preferably selected from those which dissolve the polycarbonate resin and do not cause the growth of phthalocyanine crystals which hinder the performance. Examples of the solvent having such a property include: Hydrocarbons such as toluene, xylene, mineral spirits,
Acetone, methyl ethyl ketone, methyl butyl ketone,
Ketones such as cyclohexanone, halogenated hydrocarbons such as dichloromethane, dichloroethane, trichloroethane and chlorobenzene, ethers such as tetrahydrofuran, dioxane, monoglyme, diglyme and anisole, methanol, ethanol, propanol, butanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve. , Alcohols such as cyclohexanol, esters such as ethyl acetate, propyl acetate and butyl acetate, and amides such as dimethylformamide and N-methylpyrrolidone. For these solvents,
One kind may be used alone or two or more kinds may be mixed and used.

As a coating method, if necessary, a solvent such as toluene or cyclohexanone is added to the above mixture to adjust the viscosity, and then an air doctor coater, a plate coater,
Dip coater, ring coater, rod coater,
The film is formed by a coating method such as a reverse coater, a spray coater, a hot coater, a squeeze coater, a gravure coater. After coating, it is dried until a sufficient charging potential is imparted as a photoconductive layer. Usually, the drying is performed at a temperature of 30 to 300 ° C. for 1 minute to 24 hours after preliminary drying at room temperature.

The electrophotographic photosensitive member (hereinafter referred to as the photosensitive member of the present invention) manufactured according to the above-mentioned means according to the present invention has a resin / photoconductive material of titanyl phthalocyanine in a weight ratio of 1: 1. That is all. Therefore, for example, the amount of resin is larger than in the case of the conventional photoconductor using zinc oxide in which the weight ratio of resin / photoconductive material is 0.2. Therefore, it is possible to realize a photoconductor having a physical strength of the coating and being highly flexible. Further, an undercoat layer or an overcoat layer may be provided for the purpose of improving various characteristics of the photoreceptor. Further, additives such as antioxidants may be added for the purpose of improving stability and the like.

The photoconductor of the present invention produced as described above is used by positive charging, has a large adhesiveness with a conductive support, has good moisture resistance, has little change with time, and has a toxicity problem. It is characterized in that it is practically excellent in that it is low in quantity, easy to manufacture and inexpensive. The photoconductor of the present invention obtained as described above can be used as a photoconductor for digital light input because it has a specific flow of photocurrent as compared with the case of the conventional photoconductor.

That is, in the conventional photoconductor, as described above, the photocurrent of an amount linearly corresponding to (the logarithmic value of) the input light amount flows, whereas the photoconductor of the present invention has a certain input. The photocurrent does not flow up to the light amount, or it is a very small amount,
Immediately after the light amount is exceeded, the photocurrent suddenly starts to flow. In digital recording, the image gradation is expressed by the dot area. Therefore, the photosensitivity characteristics of the photoconductor used in this recording method are preferably those described above. This is because, even if the laser spot is accurately modulated by the optical system, the distribution of the light quantity of the spot itself and the halo cannot be avoided in principle. Therefore, in the conventional photoconductor, which changes the light energy (input light amount) stepwise, the dot pattern changes due to the light amount change, which causes fog as noise. Therefore, the photoconductor of the present invention is a photoconductor advantageous for a digital light input photoconductor.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, titanyl phthalocyanine is synthesized according to a known method and subjected to mechanical and chemical treatments such as grinding and solvent treatment to obtain a desired crystal form, which is used in the present invention. It is prepared by dispersing it in the polycarbonate resin specified in 1. and applying it on a conductive substrate. The polycarbonate resin may be composed only of the structural unit represented by the general formula [I], or may be a copolymer resin with another dihydroxy compound. The titanyl phthalocyanine and the polycarbonate resin are mixed in a weight ratio of about 1: 1 to 10, and a photosensitive layer is formed by coating the conductive substrate on a conductive substrate. In preparing a photoconductor, an undercoat layer or an overcoat layer may be provided to improve various properties, or an additive such as an antioxidant conventionally used such as an antioxidant may be added to the photosensitive layer to improve stability. It is optionally implemented as necessary. Hereinafter, the present invention will be described with reference to examples.

[0029]

【Example】

<Production Example of titanyl phthalocyanine> 58 g of 1,3-diiminoisoindoline and 51 g of tetrabutoxytitanium are reacted in 300 ml of α-chloronaphthalene at 210 ° C. for 5 hours, and then heat filtered at 150 ° C. to obtain α-chloronaphthalene, It was washed with dimethylformamide (DMF) in this order.
Then, it was washed with hot DMF, hot water and methanol and dried to obtain 51 g of titanyl phthalocyanine. 100 ml of 6 g of this titanyl phthalocyanine and 50 g of glass beads
The mixture was placed in a polybin of No. 1 and ground for 40 hours with a paint shaker (Red Devil Co.). Then, the titanyl phthalocyanine was separated from the glass beads with methanol, and the obtained titanyl phthalocyanine was washed with 100 ml of water. This titanyl phthalocyanine wet cake is water 100m
1 and dichlorobenzene (10 ml) were added and the mixture was stirred for 1 hour, filtered and washed with methanol to obtain 4.3 g of titanyl phthalocyanine. The resulting titanyl phthalocyanine had a black angle (2θ ± 0.2 °) of 9.5 °, 24.
It was a crystal having peaks at 1 ° and 27.3 °. Of these, the intensity of the diffraction peak at 27.3 ° is the strongest.

<Production Example 1 of Polycarbonate Resin> A 2 l flask equipped with a stirrer, a reflux condenser, a thermometer, a gas introduction tube, a pH electrode and a dropping funnel was replaced with nitrogen, and then 1,
1-bis (4-hydroxyphenyl) -cyclohexane (147.4 g, 0.55 mol), sodium hydrogen sulfite (0.11 g), aqueous sodium hydroxide solution (NaO
H: 55 g, 1.38 mol, water: 600 ml) and methylene chloride (400 ml) were added. The reaction temperature is 23-27
Phosgene while maintaining vigorous stirring at ℃
Blow in until H drops to 7. The time required for the reaction is about 2 hours. About 70 g of phosgene was used. Next, aqueous sodium hydroxide solution (NaOH: 30 g, water: 30
ml), benzyltriethylammonium chloride (4.8
g) was added, and the mixture was vigorously stirred at 25 to 35 ° C for 1 hour. After completion of the reaction, the organic phase is separated from the aqueous phase, and the organic phase is washed with water (50
It was washed 3 times with 0 ml). Furthermore, 2% HCl aqueous solution (50
It was washed with 0 ml) and water (500 ml). After washing, the mixture was poured into methanol, filtered, and dried under reduced pressure at 100 ° C. for 10 hours.

<Production Example 2 of Polycarbonate Resin> 1,1-bis (4-hydroxyphenyl) -cyclohexane (147.4 g, 0.55 mol) of Production Example 1 was added to 1,1-
Bis (4-hydroxyphenyl) -cyclohexane (7
3.7 g, 0.275 mol), bisphenol A (6
2.5 g, 0.275 mol), and polymerized in the same manner as in Production Example 1.

<Production Example 3 of Polycarbonate Resin> 1,1-bis (4-hydroxyphenyl) -cyclohexane (147.4 g, 0.55 mol) of Production Example 1 was added to 1,1-
Bis (4-hydroxyphenyl) -cyclohexane (7
3.7 g, 0.275 mol), bisphenol F (55
g, 0.275 mol) and polymerized in the same manner as in Production Example 1.

<Production Example 4 of Polycarbonate Resin> 1,1-bis (4-hydroxyphenyl) -cyclohexane (147.4 g, 0.55 mol) of Production Example 1 was added to 1,1-
Polymerization was carried out in the same manner as in Production Example 1 except that bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (170.5 g, 0.275 mol) and bisphenol A (62.5 g, 0.275 mol) were used. .

<Production Example 5 of Polycarbonate Resin> 1,1-bis (4-hydroxyphenyl) -cyclohexane (147.4 g, 0.55 mol) of Production Example 1 was added to 1,1-
Bis (4-hydroxyphenyl) -cyclohexane (7
3.7 g, 0.275 mol), 2,2-bis (4-hydroxyphenyl) -butane (66.55 g, 0.275)
Mol) and polymerized in the same manner as in Production Example 1.

<Production Example 6 of Polycarbonate Resin> 1,2-bis (4-hydroxyphenyl) -cyclohexane of Production Example 1 (147.4 g, 0.55 mol) was added to 2,2-
Bis (4-hydroxyphenyl) -propane (125
g, 0.55 mol) and polymerized in the same manner as in Production Example 1.

Example 1 0.25 g of titanyl phthalocyanine obtained in the production example
To the polycarbonate resin 1.0 obtained in Production Example 1.
g, toluene 6.5 g, glass beads (diameter 2 mm) 1
It was sealed together with 2 g in a glass container and dispersed for 4 hours with a paint shaker (manufactured by Red Devil Co.), and after dispersion, glass beads were separated to obtain a photoreceptor coating solution. This photoreceptor coating liquid was applied on a degreased aluminum sheet having a thickness of 90 μm by the wire bar method, preliminarily dried at room temperature, and then dried in an oven at 100 ° C. for 1 hour. As a result, a photoreceptor having a film thickness of 15.5 μm was obtained.

Example 2 The same treatment as in Example 1 was carried out except that the polycarbonate resin of Example 1 was replaced with the polycarbonate resin obtained in Production Example 2 to obtain a photoreceptor having a film thickness of 15.8 μm. Example 3 The same process as in Example 1 was carried out except that the polycarbonate resin obtained in Production Example 3 was used instead of the polycarbonate resin obtained in Production Example 3 to obtain a photoreceptor having a film thickness of 15.6 μm.

Example 4 The same procedure as in Example 1 was carried out except that the polycarbonate resin obtained in Production Example 4 was used instead of the polycarbonate resin obtained in Production Example 4 to obtain a photoreceptor having a film thickness of 16.0 μm. Example 5 The same process as in Example 1 was carried out except that the polycarbonate resin obtained in Production Example 5 was used instead of the polycarbonate resin obtained in Production Example 5 to obtain a photoreceptor having a film thickness of 15.7 μm.

Example 6 The same treatment as in Example 1 was carried out except that the polycarbonate resin of Example 1 was replaced with a commercially available polycarbonate resin (APEC-HT, manufactured by Bayer Japan), and the film thickness was 15.7 μm.
m photoconductor was obtained. Example 7 The same treatment as in Example 1 was carried out except that the polycarbonate resin of Example 1 was replaced with a commercially available polycarbonate resin (Upilon Z200, manufactured by Mitsubishi Gas Chemical Co., Ltd.), and the film thickness was 15.7 μm.
m photoconductor was obtained. Hereinafter, a comparative example used for evaluating the polycarbonate resin according to each example of the present invention will be described.

Comparative Example 1 0.25 g of titanyl phthalocyanine obtained in Production Example was used as a polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.).
1.0 g, toluene 6.5 g, glass beads (diameter 2 m
m) Sealed together with 12 g in a glass container, dispersed with a paint shaker (made by Red Devil Co.) for 4 hours,
After the dispersion, the glass beads were separated to obtain a photoreceptor coating liquid. This photoreceptor coating liquid was applied on a degreased aluminum sheet having a thickness of 90 μm by the wire bar method, preliminarily dried at room temperature, and then dried in an oven at 100 ° C. for 1 hour. As a result, a photoreceptor having a film thickness of 16.2 μm was obtained. Comparative Example 2 The same treatment as in Comparative Example 1 was carried out except that the polyester resin of Comparative Example 1 was replaced with the polycarbonate resin obtained in Production Example 6 to obtain a photoreceptor having a film thickness of 15.5 μm.

<Evaluation of Electrophotographic Photoconductor of the Present Invention> The photosensitivity of the photoconductors of the respective Examples and Comparative Examples obtained above was measured by a photoconductor evaluation device (Cynthia-55, manufactured by Gentec). It evaluated using. First, corona charging was performed at a voltage of +6.0 KV, and monochromatic light of 780 nm with different light intensity was applied to each corona-charged photoconductor, and the light decay time curve for each light intensity (characteristic curve of surface potential against irradiation time) ) Was measured. Then, the surface potential after irradiation for a certain period of time (here, 0.075 seconds) obtained from the curve was plotted against the light energy. This was made into the light attenuation curve.

In the light attenuation curve, the difference between the initial potential immediately after charging is V ₀ (V) and the surface potential when the residual potential is 50 μJ / cm ² is V _r (V) is shown. Let ΔV (V ₀ −V _r ). At this time, the surface potential (V ₉₅ = ΔV × 0.95 + V _r ) obtained by adding 95% of ΔV to the residual potential is taken as “95% surface potential” V ₉₅ , and “5
The surface potential (V ₅ = ΔV × 0.05 + V _r ) obtained by adding 5% of ΔV to the residual potential is taken as “% surface potential” V ₅ .
The exposure energies that give V ₉₅ and V ₅ are obtained as “95% exposure energy” E ₉₅ and “5% exposure energy” E ₅ , respectively, and the value of E ₅ / E ₉₅ can be digitally recorded according to the following evaluation criteria. And

0 <E ₅ / E ₉₅ ≦ 5: Digital recording is possible 5 <E ₅ / E ₉₅ : Analog recording Further, of 0 <E ₅ / E ₉₅ ≦ 5, the smaller E ₉₅ is, the light sensitivity is higher. It can be said that it is excellent as an electrophotographic photoreceptor. Table 1 shows the evaluation results of the photoreceptor characteristics.

[0044]

[Table 1]

[0045]

As described above, the photoconductor in which the specific crystalline form of titanyl phthalocyanine according to the present invention is dispersed in the specific polycarbonate resin has a peculiar manner of flow of optical power with respect to light input, that is, an analog. Both light and digital light can be output as a digital signal. Therefore, it can be used for a digital recording type electrophotography, and can realize a high-quality image with a sharp edge even when used for a conventional PPC (analog light input) photoconductor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Suzuki 1000 Kamoshida-cho, Aoba-ku, Yokohama-shi, Kanagawa Mitsubishi Chemical Corporation Yokohama Research Institute

Claims (5)

[Claims] 1. A black angle (2θ) of an X-ray diffraction spectrum.
Disperse titanyl phthalocyanine showing peaks at 9.5 °, 24.1 ° and 27.3 ° in a polycarbonate resin containing a specific structural unit represented by the following general formula [I]. An electrophotographic photosensitive member having a threshold value in a light attenuation curve. Embedded image (In the formula, R is an alkyl group having 1 to 6 carbon atoms, an alkoxy group, or a phenyl group, n is 0 to 6, and X ¹ and X
² is the same or independent, and shows a hydrogen atom, a halogen atom, or a C1-C6 alkyl group, 1 and m are the same or independent, and are 0-4. ) 2. The electrophotographic photosensitive member according to claim 1, wherein the polycarbonate resin is a resin composed of only the specific structural unit represented by the general formula [I]. 3. The electrophotographic photosensitive member according to claim 1, wherein the polycarbonate resin is a resin composed of the specific structural unit represented by the general formula [I] and another structural unit. 4. The electrophotographic photoreceptor according to claim 1, wherein the mixing ratio of titanyl phthalocyanine and the polycarbonate resin is 1 to 1 by weight. 5. The electrophotographic photoreceptor according to claim 1, wherein a photosensitive layer made of a mixture of titanyl phthalocyanine and a polycarbonate resin is formed on a conductive substrate.