JP2000147801A - Electrophotographic sensitive body, process cartridge and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic sensitive body which has, as excellent electrophotographic characteristics, a good resistance to electricity due to direct electrification, high sensitivity, excellent durability at the time of repeated use, small memory, and in which the fluctuation in bright part potential due to the transfer electrification is small, a memory by positive electrification hardly forms and further the fluctuation in the bright part potential is small even in the case of electrification system wherein an alternating current voltage is overlaid, and which is capable of supplying a good image. SOLUTION: The electrophotographic sensitive body has an electrifying member which is provided such a manner that the electrifying member is brought into contact with a electrophotographic sensitive body having a charge generating layer and a charge transporting layer on an electroconductive supporting body, and is used in an electrophotographic device wherein the photosensitive body is electrified by the electrifying member. In this case, the charge generating layer contains an organic pigment as charge generating material and a binder resin and further contains a charge transporting material. The maximum longitudinal diameter of the particles contained in the charge generating layer is in the range of 1-1,500 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic photoreceptor,
More specifically, the present invention relates to an electrophotographic photosensitive member having a photosensitive layer containing a specific material, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus.

[0002]

2. Description of the Related Art An electrophotographic method is disclosed in U.S. Pat.
As shown in JP-A-91, a photoconductive material whose support changes in electric resistance according to the amount of irradiation received during image exposure and is coated with an insulating material in a dark place is used. The basic characteristics required of an electrophotographic photoreceptor using this photoconductive material include (1) being able to be charged to an appropriate potential in a dark place, (2) being small in potential dissipation in a dark place, (3) Quickly dissipating the charge by light irradiation.

Heretofore, as an electrophotographic photoreceptor, an inorganic photoreceptor having a photosensitive layer mainly containing an inorganic photoconductive compound such as selenium, zinc oxide, and cadmium sulfide has been widely used. However, they satisfy the above conditions (1) to (3), but are not always satisfactory in heat stability, moisture resistance, durability, and productivity.

In order to overcome the disadvantages of inorganic photoreceptors, electrophotographic photoreceptors containing various organic photoconductive compounds as main components have been actively developed in recent years. For example, US Pat.
Japanese Patent No. 37851 discloses a photoreceptor having a charge transport layer containing triallyl pyrazoline, US Pat. No. 3,871,880.
Japanese Patent Application Laid-Open No. H11-163873 discloses a photoreceptor including a charge generation layer composed of a perylene pigment derivative and a charge transport layer composed of a condensate of 3-propylene and formaldehyde.

Electrophotographic photoreceptors using these organic photoconductive compounds are used as function-separated type photoreceptors in which a charge transport layer and a charge generation layer are laminated in order to satisfy both electrical and mechanical properties. Often done. On the other hand, as a matter of course, the electrophotographic photoreceptor is required to have sensitivity, electrical characteristics, and even optical characteristics according to the electrophotographic process applied.

The charge generation layer is generally formed by applying and drying a coating material prepared by dispersing and dissolving an organic pigment in a dispersion medium together with a binder if necessary. In this method, it is required that the dispersibility of the organic pigment and the binder in the paint is good. Therefore, it is desired that the particles of the organic pigment and the binder form primary particles as fine as possible and ideally, in order to make the force causing aggregation such as van der Waals force and electrostatic attraction difficult.

The miniaturization of particles is effective for increasing the light absorption efficiency. In order to efficiently inject generated charge carriers into the charge transport layer, the charge generation layer is preferably as thin as possible. For that purpose, the pigment and binder particles need to be fine.

There have been many attempts to increase the sensitivity of an electrophotographic photosensitive member by adding a charge transport material to a charge generation layer. For example, JP-A-57-14844, JP-A-58-187931, JP-A-60-2621
No. 62, for example. These include simply adding a charge transport material to the charge generation layer, combining the charge transport material with a charge transport material having a specific structure, and adding the charge transport material to each layer constituting the electrophotographic photoreceptor. .

Further, in recent years, a direct charging method in which a voltage is directly applied to a charging member as disclosed in JP-A-57-17826 and JP-A-58-40566 to apply a charge to an electrophotographic photoreceptor. The method is becoming mainstream. This is a method in which a roller-shaped charging member made of conductive rubber or the like is brought into direct contact with the electrophotographic photosensitive member to apply a charge, and the amount of ozone generated is significantly smaller than that of a scorotron or the like. While about 80% of the flowing current flows through the shield and is wasted, direct charging has the merit that it is very economical without this waste.

[0010] However, direct charging has a drawback that charging stability is very poor due to charging by discharge according to Paschen's rule. As a countermeasure, a so-called AC / DC charging system in which an AC voltage is superimposed on a DC voltage has been devised (JP-A-63-149668).

Although the charging method has improved the stability during charging, the amount of discharge on the surface of the electrophotographic photosensitive member is greatly increased due to the superposition of AC, and the shaving amount of the electrophotographic photosensitive member is increased. This causes a new disadvantage that the electrical strength as well as the mechanical strength is required. As described above, the charge transport layer is required to have strength against electric shock due to direct charging and durability against mechanical external forces such as toner development, a transfer process, and surface cleaning.

More specifically, there is a demand for durability against mechanical deterioration and electrical deterioration in which the surface is worn or scratched due to discharge during charging and rubbing of the cleaning member. Mechanical deterioration is particularly inferior to mechanical deterioration of an organic photoreceptor which is often physically soft unlike an inorganic photoreceptor, and improvement in durability is particularly desired.

Further, as the surface layer is scraped, the electric field strength and the capacitance applied to the electrophotographic photosensitive member naturally change. This is one of the causes of potential fluctuations. To prevent this, it is desired to prevent surface wear and to minimize potential fluctuations even if worn.

Further, there has been a drawback that since an AC voltage is applied, charges are easily retained at the interface between the charge transport layer and the charge generation layer, and the potential of the light portion is easily fluctuated. Further, the phenomenon that the light portion potential fluctuates due to the application of the transfer charge is becoming remarkable with the speeding up of the electrophotographic apparatus.
In general, in the case of a digital electrophotographic apparatus,
The transfer current is positive, and depending on the material, the cleaning blade and the charging member that are in contact with the photoreceptor are positively charged by the contact.

Further, in an electrophotographic photosensitive member used repeatedly, a high current is repeatedly turned on and off in the photosensitive member by charging and exposure. As a result, the charge moving in the photoconductor remains at a trap site in the photoconductor, resulting in a residual potential. This causes fluctuations in the photoconductor potential due to repeated use.

[0016]

SUMMARY OF THE INVENTION It is an object of the present invention to provide excellent electrophotographic characteristics, such as good electrical resistance due to direct charging, high sensitivity, excellent repetition characteristics due to durability, small memory, and transfer charging. An electrophotographic photoreceptor capable of supplying a good image with a small change in the light portion potential and a small change in the light portion potential even in a charging method in which an AC voltage is superimposed. And a process cartridge having the same.

[0017]

According to the present invention, there is provided a charging member disposed in contact with an electrophotographic photosensitive member having a charge generating layer and a charge transport layer on a conductive support, and the charging member is In an electrophotographic photoreceptor used for an electrophotographic apparatus for charging a photoreceptor, the charge generation layer contains an organic pigment as a charge generation material and a binder resin, and particles present in the charge generation layer have a maximum major axis of 1 nm to 1500.
The present invention provides an electrophotographic photosensitive member having a charge transporting material in a charge generation layer, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus.

[0018]

Embodiments of the present invention will be described below.

In the electrophotographic photoreceptor of the present invention, the organic pigment in the charge generation layer may be a bisazo compound or a trisazo compound shown below,

[0020]

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Wherein R ¹¹ and R ¹² are the same or different,
It is a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. R ¹³ is a hydrogen atom or a halogen atom.

[0022]

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[0023]

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[0024]

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In the formulas (2), (3) and (4), R ²¹ and R
²² is the same or different and is a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. R ²³ is a hydrogen atom or a halogen atom.

[0026]

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Wherein R ³¹ and R ³² are the same or different,
It is a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. R ³³ is a hydrogen atom or a halogen atom.

Alternatively, the CuKα characteristic X-ray diffraction black angles (2θ ± 0.2 °) of 9.0 °, 14.2 °, 23.
Oxytitanium phthalocyanine having strong peaks at 9 ° and 27.1 °, or 7.4 ° and 28.2 ° of the characteristic X-ray diffraction black angle (2θ ± 0.2 °) of CuKα.
Hydroxygallium phthalocyanine having a strong peak to, these may be used alone or may be used in combination, and the charge transport material added to the charge transport layer or the charge generation layer has a structure shown below, These are electrophotographic photoreceptors which may be used alone or in combination.

[0029]

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Where Ar⁴¹And Ar⁴²Has a substituent
A good aromatic ring group;⁴¹And R ⁴²Is a hydrogen atom, halo
A gen atom, an alkyl group or an alkoxy group. R⁴³Is
It is a hydrogen atom or a halogen atom.

[0031]

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In the formula, X represents -CH- or -CH = CH-. R ⁵¹ and R ⁵² represent an alkyl group, an aralkyl group or an aromatic ring group which may have a substituent. Also, R ⁵³
And R ⁵⁴ represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. Ar ⁵¹ represents an aryl group.

Further, the electrophotographic photoreceptor is characterized in that the charge transport layer contains a polymer having a structural unit represented by the following structural formula (8).

[0034]

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In the formula, X is -CR ⁹ R ^10- (where R ⁹ and R ¹⁰ are each independently a hydrogen atom, a trifluoromethyl group,
An alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms), an optionally substituted 1,1-cycloalkylene group having 5 to 11 carbon atoms, α, ω having 2 to 10 carbon atoms
-Alkylene group, single bond, -O-, -S-, -SO-,
Or —SO ₂ —. R ^{1 to} R ⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group which may be substituted,
An aryl group and an alkylene group.

The electrophotographic photoreceptor, process cartridge and electrophotographic apparatus according to the present invention have excellent electrophotographic properties such as good electrical resistance due to direct charging, high sensitivity, excellent repetition characteristics due to durability, small memory, The change in the light portion potential due to the transfer charging is small, and the change in the light portion potential is small even in the charging method in which the AC voltage is superposed, so that a good image can be supplied.

Although the exact reason is unknown, the environment in which the electrophotographic photoreceptor is placed in the present application is one in which the charging member is directly exposed to a DC and / or AC electric field. Therefore, when a direct current and an alternating electric field are applied, first, the maximum length of the charge generation material of the charge generation layer and the particles of the binder resin (the reason for defining the maximum length here is that the charge generation material varies depending on its type. It takes a shape, but it is roughly divided into a spherical shape and a needle shape, and by taking the maximum major axis, it is easy to find the greatest common divisor of that shape in both shapes, reflecting the size of the shape When the particle diameter exceeds 1500 nm, the frequency of vibration, rotation, and contact increases due to the AC electric field between the adjacent particles together with the decrease in the light absorption rate, and the internal energy of the particles increases. Presumed to lead to a rise.

As a result, the temperature inside the particles rises and polarization occurs, and it is considered that the sensitivity or durability of the photoconductor affects the potential fluctuation. A more preferred maximum major axis is 700 nm or less. The maximum major axis of the particles of the charge generation material and the binder resin in the charge generation layer is preferably as small as possible. However, considering the size of the pigment itself, it is difficult to manufacture the charge generation layer below 1 nm by the current dispersion means.

Secondly, it is considered that an influence is exerted on the carrier in which a reverse bias such as an alternating electric field or transfer occurs at each of the charge generation layer and the charge transport layer and at the interface thereof. On the other hand, by adding the charge transporting material to the charge generating layer, the charge transporting material is scattered around the charge generating material in an image, which helps hopping of the carriers in the charge generating layer, and also at the interface. It is presumed that the injection barrier was lowered to prevent stagnation of carriers. It is considered that this makes it possible to reduce the fluctuation of the light-portion potential under reverse bias due to the transfer charging, and to reduce the fluctuation of the light-portion potential even in the charging method in which the AC voltage is superimposed.

Third, it has recently been found that the use of a polymer having a skeleton represented by the structural formula (8) in the surface layer increases its hardness and increases its resistance to external stress. Further, it was found that the addition of the charge transport material into the charge generation layer had an unexpected effect of buffering changes in electric field strength and capacitance.

The maximum major axis of the particles comprising the organic pigment and the binder resin in the charge generation layer in the present invention was measured by a transmission electron microscope under the following conditions.

For the preparation of the measurement sample, the liquid for the charge generation layer was used as a solvent with methyl ethyl ketone for 0.01 to 0.0
It is adjusted to 5 parts by weight, 50 to 100 μl is dropped on a water drop, and this is collected on a carbon support membrane to be used as a specimen. This sample is mounted in a measurement room of an electron microscope, and the inside of the room is 10 ^-7 to ^-6
Vacuum to about Torr and raise the electron beam acceleration voltage to 10
Measure at 100 KV. Photo magnification is 10,000
Shoot at ~ 100,000 times.

The halogen atom in the present invention includes a fluorine atom, a chlorine atom and a bromine atom, and the alkyl group includes a methyl group, an ethyl group, an isopropyl group, a butyl group and a tertiary butyl group. And as the alkoxy group, a methoxy group, an ethoxy group,
And propoxy groups, and as the aralkyl group,
As a benzyl group, a phenel group, or an alkylene group, an ethylene group, a trimethylene group, a propylene group, or an aromatic group (aryl group) such as a phenyl group, a tolyl group,
Examples include a kidyl group, a naphthyl group, and a benzyl group.

Equations (1), (2), (3), (4),
Of the bisazo-based compound and the trisazo-based compound represented by (5), particularly preferred examples include those having the following structures, but are not limited thereto.

An example of the equation (1) is shown in Table 1 below.

[0046]

[Table 1]

Examples of the equations (2), (3) and (4) are shown in Table 2 below.

[0048]

[Table 2]

An example of the equation (5) is shown in Table 3 below.

[0050]

[Table 3]

As for oxytitanium phthalocyanine, the black angle (2θ ± 0.
2 °) 9.0 °, 14.2 °, 23.9 °, 27.1
Oxytitanium phthalocyanine, which has a strong peak at an angle of °, is highly sensitive and effectively functions in the present invention, and is therefore preferred.

For hydroxygallium phthalocyanine, the black angle (2θ ± 2) of the characteristic X-ray diffraction of CuKα
Hydroxygallium phthalocyanine having strong peaks at 7.4 ° and 28.2 ° (0.2 °) is highly sensitive and effective in the present invention, and is preferred.

Specific examples of the structural unit of the polyarylate resin used in the present invention are shown below, but are not limited thereto.

[0054]

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[0055]

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In the electrophotographic photoreceptor of the present invention, even if the polymer is composed of the same structural unit represented by the structural formula (8), two or more different structural units represented by the structural formula (8) may be used. It may be a copolymer composed of units.

Hereinafter, the configuration of the electrophotographic photosensitive member used in the present invention will be described.

The electrophotographic photoreceptor of the present invention is preferably of a laminate type having a charge transport layer and a charge generation layer.

The conductive support to be used may be a conductive support, and may be a metal such as aluminum or stainless steel, or a metal provided with a conductive layer, paper, plastic, or the like. And the like.

A conductive layer may be provided for the purpose of covering the scratch on the support. This can be formed by dispersing conductive powder such as carbon black and metal particles in a binder resin. The thickness of the conductive layer is preferably 5 to 40.
μm, more preferably 10 to 30 μm.

An intermediate layer having an adhesive function is provided thereon. As the material of the intermediate layer, polyamide, polyvinyl alcohol, polyethylene oxide, ethyl cellulose,
Casein, polyurethane, polyether urethane and the like. These are applied by dissolving in an appropriate solvent.
The thickness of the intermediate layer is preferably 0.05 to 5 μm, more preferably 0.3 to 1 μm.

The charge generation layer is formed on the intermediate layer. The charge generation layer used in the present invention is mainly formed by adding a predetermined charge transport material at a predetermined ratio to a coating material in which a specific charge generation material and a binder resin are dispersed in a solvent, coating and drying. . The charge transport material to be added is
The solid content of the paint for the charge generation layer is preferably 0.0
The content is 1 to 200% by weight, more preferably 0.1 to 100% by weight.

The charge generation layer in the present invention is formed by a homogenizer, an ultrasonic dispersion, a ball mill, a vibrating ball mill, a sand mill, an attritor, and the like.
It is well dispersed by a method such as a roll mill and a liquid collision type high-speed disperser. At this time, in order to obtain the target particle size, the material of the dispersion medium, the diameter, the filling amount, the number of rotations of the apparatus, the pressure, the dispersion time,
It is necessary to control the particle size by appropriately setting the coating composition. The size of the particles in the charge generation layer according to the present invention is measured by directly observing with a transmission electron microscope.

Examples of the binder resin used herein include polyester resin, polyacryl resin, polyvinyl carbazole resin, phenoxy resin, polycarbonate resin, polystyrene resin, polyvinyl acetate resin, polysulfone resin, polyarylate resin, vinyldene chloride, and polyvinyl benzal. Resins and polybutyral resins are mainly used.

The ratio of the binder resin to the pigment is 1/10 to 10
10/1 is preferred, and more preferably 1.5 / 1 to 3 /
It is one. The dispersion is formed by coating and drying. The thickness of the charge generation layer is preferably 5 μm or less, more preferably 0.1 to 2 μm.

The charge transport layer is formed by applying and drying a coating material in which a charge transport material and a binder resin of the present invention are dissolved in a solvent. Examples of the charge transport material to be used include a triarylamine compound, a stilbene compound, a hydrazone compound, a pyrazoline compound, an oxazole compound, a triallylmethane compound, and a thiazole compound. In the present invention, a triarylamine-based compound and a stilbene compound, which are particularly excellent in stability, are mainly used. Examples of the binder resin include the same resins as those used for preparing the paint for the charge generation layer. In the present invention, a polyarylate resin having particularly excellent mechanical and electrical strength is mainly used.

These are combined with 0.5 to 2 times the amount of the binder resin, applied and dried to form a charge transport layer.
The thickness of the charge transport layer is preferably 5 to 40 μm, more preferably 15 to 35 μm.

FIG. 1 shows a schematic configuration of an electrophotographic apparatus using a process cartridge having an electrophotographic photosensitive member of the present invention.

In FIG. 1, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is driven to rotate around a shaft 2 in a direction of an arrow at a predetermined peripheral speed. In the rotation process, the photosensitive member 1 is uniformly charged with a predetermined positive or negative potential on its peripheral surface by the primary charging means 3 and then output from an image exposure means (not shown) such as slit exposure or laser beam scanning exposure. It receives image exposure light 4 that has been enhanced and modulated in accordance with the time-series electrical digital image signal of the desired image information. In this way, an electrostatic latent image corresponding to the target image information is sequentially formed on the peripheral surface of the photoconductor 1.

The formed electrostatic latent image is then developed.
The toner-developed image is developed by the image forming apparatus, and the developed toner-developed image is taken out from a paper feeding unit (not shown) between the photoconductor 1 and the transfer unit 6 in synchronization with the rotation of the photoconductor 1 and fed.
Then, the toner image formed and carried on the surface of the photoreceptor 1 is sequentially transferred by the transfer unit 6.

The transfer material 7 to which the toner image has been transferred is separated from the surface of the photoreceptor, introduced into the image fixing means 8 and subjected to image fixing to be printed out of the apparatus as an image formed product (print, copy). You.

After the transfer of the image, the surface of the photoreceptor 1 is cleaned by removing the untransferred toner by the cleaning means 9, and is further cleaned by a pre-exposure light 10 from a pre-exposure means (not shown).
Is used for image formation repeatedly after the charge removal processing. When the primary charging unit 3 is a contact charging unit using a charging roller or the like, the pre-exposure is not necessarily required.

In the present invention, a plurality of components such as the above-described electrophotographic photosensitive member 1, primary charging means 3, developing means 5, and cleaning means 9 are integrally connected as a process cartridge. The process cartridge may be configured to be detachable from a main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. For example, at least one of the primary charging unit 3, the developing unit 5, and the cleaning unit 9 is integrally supported together with the photoreceptor 1 to form a cartridge, which can be attached to and detached from the apparatus main body using a guide unit such as a rail 12 of the apparatus main body. Process cartridge 1
It can be 1.

When the electrophotographic apparatus is a copying machine or a printer, the image exposure light 4 is reflected or transmitted from the original, or the original is read by a sensor and converted into a signal. Laser beam scanning,
Light emitted by driving the LED array, driving the liquid crystal shutter array, and the like.

The electrophotographic photosensitive member of the present invention can be used not only for an electrophotographic copying machine but also for a laser beam printer,
It can be widely used in electrophotographic applications such as CRT printers, LED printers, liquid crystal printers, and laser plate making.

[0076]

The present invention will be described in more detail with reference to the following examples. In the examples, "parts" and "%" indicate parts by weight and% by weight, respectively.

(Example 1) 30 mmφ, 357.5 mm
The aluminum cylinder of the above was used as a support, and a coating composed of the following materials was applied on the support by a dipping method, and was thermally cured at 150 ° C. for 30 minutes to form a film having a thickness of 20 μm.
Was formed.

Conductive pigment: Barium sulfate treated with SnO ₂ 10 parts Pigment for resistance adjustment: 2 parts of titanium oxide Binder resin: 6 parts of phenol resin Leveling material: 0.001 part of silicone oil Solvent: methanol / methoxypropanol 0.2 / 0.8 20 parts

Next, 3 parts of N-methoxymethylated nylon and 3 parts of copolymerized nylon were added thereto with 65 parts of methanol /
A solution dissolved in a mixed solvent of 30 parts of n-butanol was applied by an immersion method to form an intermediate layer having a thickness of 0.5 μm.

Next, the following structural formula (9)

[0081]

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The compound 4.2 parts of cyclohexanone 60
Part and 1 mmφ glass beads, and dispersed in a sand mill at a temperature of 5 to 10 ° C. for 72 hours, and then gradually stirring 2 parts of polyvinyl butyral (trade name: Eslec BM2, manufactured by Sekisui Chemical) and 100 parts of methyl ethyl ketone while stirring. In addition to the above, the mixture was further dispersed for 3 hours using a sand mill, and this solution was prepared at a predetermined ratio, and observed with a transmission electron microscope (H7500, manufactured by Hitachi, Ltd.). Met. Further, the solid content of the liquid after the preparation was measured and was found to be 3.2%.

Next, the following structural formula (10)

[0084]

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The charge transporting material is 50
% By weight and mixed with the dispersion for charge generation layer. This was applied by an immersion method to form a charge generation layer having a thickness of 0.3 μm.

Next, 10 parts of the charge transporting material of the above structural formula (10) and 10 parts of the polymer described in Condition 1 of Table 4 were dissolved in a mixed solvent of 30 parts of monochlorobenzene / 70 parts of dichloromethane.

The polymer was prepared from a predetermined biphenol (0.0
Sodium hydroxide (0.8 g) and tetramethylammonium chloride (1 g) were dissolved in 100 ml of water and charged into a 1-liter mixer, and terephthalic acid chloride (0 ml) was added to 1,2-dichloroethane (30 ml). .0
05mol), isophthalic acid chloride (0.005mo)
The solution obtained by dissolving l) was added with stirring, stirred at a high speed for 10 minutes, and allowed to stand for 2 hours. Then, a 1,2-dichloroethane solution was recovered, and a large amount of hexane was added to the solution to obtain a polymer, which was recovered with chloroform. After collection, water washing,
A solution that had been subjected to a purification step by dissolution and dropwise addition of methanol was used. This paint was applied by a dipping method and dried at 120 ° C. for 2 hours to form a charge transport layer having a thickness of 22 μm.

Next, evaluation will be described. The apparatus used was GP215 manufactured by Canon. The produced electrophotographic photoreceptor was subjected to paper passing durability using this apparatus in an environment of 28 ° C. and a relative humidity of 60%. The sequence is one per print
Intermittent mode in which the motor stops several times.

The surface potential (bright portion potential) and the amount of decrease in the film thickness of the electrophotographic photosensitive member were measured at the initial stage of durability and at 10,000 sheets. Further, at the time of measurement, +12 μm from the transfer charger
A current of A was passed, and the bright portion potential when transfer was applied was measured. {Bright portion potential (no transfer) −bright portion potential (with transfer)}
Is shown as the transfer memory. In addition, a bias of +3 KV was applied to the photosensitive member in the circumferential direction by using an external power supply, and the potential difference between a portion to which the bias was applied and a portion to which the bias was not applied after one hour was observed. When the toner ran out, the toner was replenished and used repeatedly until a problem occurred in the image.

Further, 3000 l of a part of the electrophotographic photosensitive member
The white fluorescent lamp was exposed to light for 3 minutes with ux, and after standing for 10 minutes, the bright portion potential was measured, and the value of {bright portion potential (before irradiation) -bright portion potential (after irradiation)} was taken as the photo memory value. A Taber abrasion tester using a polishing tape was used.
For a minute, and the weight loss at that time was measured. Table 5 shows the results.

[0091]

[Table 4]

In Table 4, the mixing ratio of the terephthalic acid chloride and the isophthalic acid chloride in the monomers used is 1: 1:
It was set to 1.

Example 2 The following formula (11) was used for the charge generating material of the charge generating layer.

[0094]

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The compound 4.2 parts of cyclohexanone 60
Part and 1 mmφ glass beads, and dispersed in an atmosphere of a temperature of 10 to 20 ° C. for 64 hours in a sand mill device, and then stirring 2 parts of polyvinyl butyral (trade name: Eslec BM2, manufactured by Sekisui Chemical) and 100 parts of methyl ethyl ketone The solution was gradually added, and further dispersed for 3 hours using a sand mill. This solution was prepared at a predetermined ratio, and observed with a transmission electron microscope (H7500, manufactured by Hitachi, Ltd.). 160 nm. Further, the solid content of the liquid after the preparation was measured and was found to be 3.2%.

Next, 50% by weight of the charge transporting material of the structural formula (10) based on the solid content was added and mixed with the dispersion for the charge generating layer. This is applied by a dipping method, and the film thickness is 0.3
A μm charge generation layer was formed. Other than these, Example 1
An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above. Table 5 shows the results.

Example 3 Compound 2.1 of the structural formula (9)
Parts and 2.1 parts of the compound of the structural formula (11) were dispersed in a sand mill using a 1 mmφ glass bead and 60 parts of cyclohexanone for 70 hours in an atmosphere at a temperature of 10 ± 2 ° C., and then polyvinyl butyral (trade name: Eslek) BM
2, 2 parts of Sekisui Chemical Co., Ltd.) and 100 parts of methyl ethyl ketone were gradually added while stirring, and further dispersed for 3 hours using a sand mill, and this liquid was prepared at a predetermined ratio. (H7500), the maximum major axis of the particles was 150 nm. Further, when the solid content of the liquid after the preparation was measured, it was 3.2.
%Met.

Next, 50% by weight of the charge transporting material of the structural formula (10) based on the solid content was added and mixed with the dispersion for the charge generating layer. This is applied by a dipping method, and the film thickness is 0.3
A μm charge generation layer was formed. Other than these, Example 1
An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above. Table 5 shows the results.

Example 4 CuKα characteristic X-ray diffraction black angles (2θ ± 0.2 °) of 9.0 °, 14.2 °,
Add 3 parts of oxytitanium phthalocyanine having strong peaks at 23.9 ° and 27.1 °, 2 parts of polyvinyl butyral (trade name: Esrec BM2, manufactured by Sekisui Chemical), and 35 parts of cyclohexanone, and use 1 mmφ glass beads. The mixture was dispersed for 7 hours in an atmosphere at a temperature of 20 ± 3 ° C. using a sand mill. This liquid was prepared at a predetermined ratio and observed with a transmission electron microscope (H7500, manufactured by Hitachi, Ltd.). As a result, the maximum major axis of the particles was 210 nm.
Further, the solid content of the liquid after the preparation was measured and found to be 3.2.
%Met.

Next, 50% by weight of the charge transporting material of the structural formula (10) based on the solid content was added and mixed with the dispersion for the charge generating layer. This is applied by a dipping method, and the film thickness is 0.3
A μm charge generation layer was formed. Other than these, Example 1
An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above. Table 5 shows the results.

Example 5 Characteristics of CuKα 3 parts of hydroxygallium phthalocyanine having strong peaks at 7.4 ° and 28.2 ° of black angle (2θ ± 0.2 °) in characteristic X-ray diffraction, 3 parts of polyvinyl butyral ( Product Name: Esrec B
(M2, manufactured by Sekisui Chemical Co., Ltd.) and 35 parts of cyclohexanone, and dispersed using a 1 mmφ glass bead in a sand mill at a temperature of 20 ± 3 ° C. for 5 hours. This liquid was prepared at a predetermined ratio and observed with a transmission electron microscope (H7500, manufactured by Hitachi, Ltd.). The maximum major axis of the particles was 300 nm. Further, the solid content of the liquid after the preparation was measured and was found to be 3.2%.

Next, the charge transporting material of the structural formula (10) was added in an amount of 50% by weight based on the solid content and mixed with the dispersion for the charge generating layer. This is applied by a dipping method, and the film thickness is 0.3
A μm charge generation layer was formed. Other than these, Example 1
An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above. Table 5 shows the results.

(Example 6) The following formula (12) was used for the charge generation material of the charge generation layer.

[0104]

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13. Black angle (2θ ± 0.2 °) of 9.0 parts of compound X-ray diffraction and characteristic X-ray diffraction of CuKα;
3 parts of oxytitanium phthalocyanine having strong peaks at 2 °, 23.9 ° and 27.1 ° are dispersed for 10 hours in a sand mill at a temperature of 15 to 20 ° C. using 60 parts of cyclohexanone and 1 mmφ glass beads. ,
3 parts of polyvinyl butyral (trade name: Eslec BM2, manufactured by Sekisui Chemical) and 100 parts of methyl ethyl ketone are gradually added with stirring, and further dispersed for 3 hours using a sand mill device. Observation with a scanning electron microscope (H7500, manufactured by Hitachi, Ltd.) revealed that the maximum major axis of the particles was 170 nm. Further, the solid content of the liquid after the preparation was measured and was found to be 3.2%.

Next, 50% by weight of the charge transporting material of the structural formula (10) based on the solid content was added and mixed with the dispersion for the charge generating layer. This is applied by a dipping method, and the film thickness is 0.3
A μm charge generation layer was formed. Other than these, Example 1
An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above. Table 5 shows the results.

Example 7 Compound 4.2 of the structural formula (9)
Part was dispersed for 76 hours in a sand mill at a temperature of 5 to 10 ° C using 60 parts of cyclohexanone and 1 mmφ glass beads, and then polyvinyl butyral (trade name:
2 parts of Esrec BM2 (manufactured by Sekisui Chemical) and 100 parts of methyl ethyl ketone were gradually added with stirring, and further dispersed for 3 hours using a sand mill. This solution was prepared at a predetermined ratio, and was then measured with a transmission electron microscope (Hitachi, Ltd.). H7
500), the maximum major axis of the particles was 130 n
m. Further, the solid content of the liquid after the preparation was measured and was found to be 3.2%.

Next, the following structural formula (13)

[0109]

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The charge transporting material is 50
% By weight and mixed with the dispersion for charge generation layer. This was applied by an immersion method to form a charge generation layer having a thickness of 0.3 μm. Except for these, an electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1. Table 5 shows the results.

Example 8 Compound 4.2 of the structural formula (9)
Part was dispersed for 72 hours in a sand mill at a temperature of 5 to 10 ° C using 60 parts of cyclohexanone and 1 mmφ glass beads, and then polyvinyl butyral (trade name:
2 parts of Esrec BM2 (manufactured by Sekisui Chemical) and 100 parts of methyl ethyl ketone were gradually added with stirring, and further dispersed for 3 hours using a sand mill. This solution was prepared at a predetermined ratio, and was then measured with a transmission electron microscope (Hitachi, Ltd.). H7
500), the maximum major axis of the particles was 130 n
m. Further, the solid content of the liquid after the preparation was measured and was found to be 3.2%.

Next, 30% by weight of the charge transporting material of the structural formula (10) based on the solid content was added and mixed with the dispersion for the charge generating layer. This is applied by a dipping method, and the film thickness is 0.3
A μm charge generation layer was formed. Other than these, Example 1
An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above. Table 5 shows the results.

Example 9 Compound 4.2 of the structural formula (9)
Part was prepared by using a sand mill with 60 parts of cyclohexanone and 1 mmφ glass bead at a temperature of 5 to 10 ° C.
After dispersing for 2 hours, 2 parts of polyvinyl butyral (trade name: Eslec BM2, manufactured by Sekisui Chemical) and 100 parts of methyl ethyl ketone are gradually added with stirring using a sand mill, and dispersed for 3 hours. And a transmission electron microscope (H750, manufactured by Hitachi, Ltd.)
When observed in 0), the maximum major axis of the particles was 130 nm. Further, the solid content of the liquid after the preparation was measured and was found to be 3.2%.

Next, the charge transport material of the structural formula (10) was added in an amount of 10% by weight based on the solid content, and mixed with the dispersion for the charge generation layer. This is applied by a dipping method, and the film thickness is 0.3
A μm charge generation layer was formed. Other than these, Example 1
An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above. Table 5 shows the results.

Example 10 Compound of Structural Formula (9)
Two parts were dispersed for 72 hours in an atmosphere of 5 to 10 ° C. using a sand mill using 60 parts of cyclohexanone and 1 mmφ glass beads, and then polyvinyl butyral (trade name:
2 parts of Esrec BM2 (manufactured by Sekisui Chemical) and 100 parts of methyl ethyl ketone were gradually added with stirring, and further dispersed for 3 hours using a sand mill. This solution was prepared at a predetermined ratio, and was then measured with a transmission electron microscope (Hitachi, Ltd.). H7
Observed at 500), the maximum major axis of the particles was 190 n.
m. Further, the solid content of the liquid after the preparation was measured and was found to be 3.2%.

Next, 3% by weight of the charge transporting material of the structural formula (10) based on the solid content was added and mixed with the dispersion for the charge generating layer. This is applied by a dipping method, and the film thickness is 0.3 μm.
m of the charge generation layer was formed. Except for these, an electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1. Table 5 shows the results.

(Examples 11 to 14) Except that the binder resin of the charge transport layer used under the conditions 2 to 5 in Table 4 was used.
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1. Table 5 shows the results.

[0118]

[Table 5]

Comparative Example 1 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that no charge transporting material was added to the charge generating layer. Table 6 shows the results.

(Comparative Example 2) In Example 1, the pre-dispersion time was set to 12 hours, and the prepared liquid was prepared at a predetermined ratio, and the transmission electron microscope (H7, manufactured by Hitachi, Ltd .;
500), the maximum major axis of the particles was 1900
A similar electrophotographic photoreceptor was prepared and evaluated except for the nm. Table 6 shows the results.

Comparative Example 3 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the binder resin of the charge transport layer had the following structural formula (14) and no charge transport material was added to the charge generation layer. The body was created and evaluated. Table 6 shows the results.

[0122]

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[0123]

[Table 6]

[0124]

The electrophotographic photoreceptor of the present invention has high sensitivity without losing the mechanical strength even when it is directly charged, and has a repetitive characteristic photo memory due to durability and excellent in the fluctuation of the light portion potential due to transfer charging. An electrophotographic photoreceptor that hardly causes a memory due to charging, has a small alternating current, and has a small fluctuation in the light portion potential, and can supply a good image, and a process cartridge using the electrophotographic photoreceptor. It has become possible to provide an electrophotographic apparatus.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus using a process cartridge having an electrophotographic photosensitive member of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 5/06 354 G03G 5/06 354Z 360 360 365 365 365A 366 366 367 367 371 371 371

Claims (5)

[Claims] 1. An electrophotographic apparatus comprising: a charging member disposed in contact with an electrophotographic photosensitive member having a charge generation layer and a charge transport layer on a conductive support; and charging the photosensitive member from the charging member. In the electrophotographic photoreceptor used in (1), the charge generation layer contains an organic pigment as a charge generation material and a binder resin, the maximum major axis of the particles present in the charge generation layer is in the range of 1 nm to 1500 nm, and An electrophotographic photoreceptor comprising a charge transport material in a charge generation layer. 2. The organic pigment according to claim 1, wherein the organic pigment is
Compound, trisazo compound,(Where R¹¹And R¹²Are the same or different and are a hydrogen atom,
A halogen atom, an alkyl group or an alkoxy group;
¹³Is a hydrogen atom or a halogen atom.Embedded imageEmbedded image(In the formulas (2), (3) and (4), R^{twenty one}And R^{twenty two}Is the same or
Is different from a hydrogen atom, a halogen atom, an alkyl group or
R is an alkoxy group;^{twenty three}Is a hydrogen atom or a halogen atom
Is)(Where R³¹And R³²Are the same or different and are a hydrogen atom,
A halogen atom, an alkyl group or an alkoxy group;
³³Is a hydrogen atom or a halogen atom) or the black angle (2θ ±) of the characteristic X-ray diffraction of CuKα.
0.2 °) 9.0 °, 14.2 °, 23.9 °, 2
Oxytitanium phthalo having a strong peak at 7.1 °
Characteristic X-ray diffraction black of cyanine or CuKα
A strong pin at the angle (2θ ± 0.2 °) of 7.4 ° and 28.2 °
Hydroxygallium phthalocyanine
These may be used alone or in combination.
And added to the charge transport layer or the charge generation layer.
Charge transporting materials have the structures shown below,
The method according to claim 1, which may be used alone or in combination.
Electrophotographic photoreceptor;(Wherein, Ar⁴¹And Ar⁴²Is an aromatic which may have a substituent
A ring group;⁴¹And R ⁴²Is a hydrogen atom, a halogen atom,
R is an alkyl group or an alkoxy group;⁴³Is a hydrogen atom or
Is a halogen atom.(Wherein X represents -CH- or -CH = CH-;
R⁵¹And R⁵²Is an alkyl, aralkyl or substituted
An aromatic ring group which may have a group;⁵³And R⁵⁴
Is a hydrogen atom, halogen atom, alkyl group or alkoxy
Represents a group; Ar⁵¹Represents an aryl group) 3. The electrophotographic photoreceptor according to claim 1, wherein the charge transporting layer contains a polymer having a structural unit represented by the following structural formula (8): (In the formula, X is -CR ⁹ R ^10- (where R ⁹ and R ¹⁰ each independently represent a hydrogen atom, a trifluoromethyl group,
An alkyl group having 6 or an aryl group having 6 to 12 carbon atoms), an optionally substituted 1,1-cycloalkylene group having 5 to 11 carbon atoms, an α, ω-alkylene group having 2 to 10 carbon atoms, single bond, -O -, - S -, - SO-, or -SO ₂
R ^{1 to} R ⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group which may be substituted, an aryl group,
An alkylene group) 4. A charging unit for charging the electrophotographic photosensitive member according to claim 1, wherein the charging unit charges the electrophotographic photosensitive member.
Integrated with at least one unit selected from the group consisting of a developing unit for developing the electrophotographic photosensitive member on which the electrostatic latent image is formed with toner, and a cleaning unit for collecting residual toner on the photosensitive member after the transfer process And a process cartridge which is detachably mounted on the main body of the electrophotographic apparatus. 5. An electrophotographic photosensitive member according to claim 1, a charging means for charging the electrophotographic photosensitive member, and image exposure of the charged electrophotographic photosensitive member to form an electrostatic latent image. An electrophotographic apparatus comprising: an image exposing unit that develops an electrostatic latent image with toner; and a transfer unit that thermally transfers a toner image on a transfer material.