JP2002251022A - Electrophotographic photoreceptor, process cartridge and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor where the reproducibility of dots generated in a higher-speed and higher-resolution electrophotographic process is not deteriorated and whose potential variation due to endurance does not get worse, and a process cartridge and an electrophotographic device. SOLUTION: This electrophotographic photoreceptor is used on an electrophotographic process condition that R>=1200 and R×r>=1.9×10<3> when resolution in the electrophotographic process is defined as R (dpi) and the revolving speed of the electrophotographic photoreceptor is defined as r (rotation/ second). The sensitive body is provided with a photoreceptive layer on a conductive supporting body and the contact angle of the surface of the photoreceptive layer to pure water is >=100 deg.. Thus, the electrophotographic photoreceptor, and the process cartridge and the electrophotographic device having the electrophotographic photoreceptor are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic photoreceptor,
More particularly, the present invention relates to an electrophotographic photosensitive member including a photosensitive layer having a specific pure water contact angle, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic device.

[0002]

2. Description of the Related Art Electrophotographic copying machines and printers have become widespread, and digital image processing systems have become popular with the advancement of computers, and the speed, resolution, image quality, durability and durability have been increasing. Cost reduction is required.

[0003] In response to such demands, the functions required of the electrophotographic photoreceptor are also increasing.

In an electrophotographic process of higher speed and higher resolution, an electrophotographic photosensitive member is required to have better responsiveness of an optical signal, to be excellent in image formation, to have higher durability, and the like. Under these circumstances, when the resolution in the electrophotographic process is R (dpi) and the number of rotations of the electrophotographic photosensitive member is r (rotation / second), R ≧ 1200 and R · r ≧
Under the electrophotographic process conditions of 1.9 × 10 ³ , FIG.
When such an isolated dot image was output, it was found that the reproducibility of dots was inferior to that in the conventional electrophotographic process, and the problem that dots were not formed well occurred. This is presumably because image formation such as a latent image on the electrophotographic photosensitive member, toner development, and toner transfer to paper cannot follow the high-speed process. Furthermore, in such a high-speed, high-resolution electrophotographic process, the durability was evaluated, and the fluctuation of the potential of the electrophotographic photosensitive member due to the durability was larger than that in the conventional electrophotographic process.
It was found that the image density was not stable.

[0005] Electrophotographic photoreceptors have hitherto been studied from various directions, and particularly the surface layer has been particularly studied because of its close relationship with durability. Among them, as one of the surface properties, the contact angle of the electrophotographic photosensitive member surface with pure water affects the slip property, abrasion resistance, mold release property and the like. If the contact angle to water is 90 degrees or more,
It is disclosed that toner transfer and cleaning are excellent.

[0006] In the present study, it was found that there was an unexpected correlation between a problem in a high-speed process like never before and the contact angle of the electrophotographic photosensitive member surface.
The present invention has been completed.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photosensitive apparatus in which dot reproducibility caused in a higher-speed and higher-resolution electrophotographic process is not deteriorated, and fluctuation of potential of an electrophotographic photosensitive member due to durability is not deteriorated. It provides the body.

Another object of the present invention is to provide a process cartridge having the above electrophotographic photosensitive member and an electrophotographic apparatus.

[0009]

According to the present invention, when the resolution in the electrophotographic process is R (dpi) and the number of rotations of the electrophotographic photosensitive member is r (rotation / second), R ≧ 1200.
And an electrophotographic photoconductor used under electrophotographic process conditions of R · r ≧ 1.9 × 10 ^{3, wherein} the electrophotographic photoconductor is provided with a photosensitive layer on a conductive support, An electrophotographic photosensitive member having a surface with a contact angle of 100 degrees or more with pure water, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus are provided.

[0010]

Embodiments of the present invention will be described below in detail.

The present inventors have studied the characteristics of an electrophotographic photosensitive member in a higher-speed, higher-resolution electrophotographic process, and found that there is a correlation between the surface characteristics of the electrophotographic photosensitive member and image and potential fluctuations. I noticed that. When the contact angle of the electrophotographic photoreceptor surface with pure water is 100 degrees or more, the reproducibility of the dots of the output image is good and the potential fluctuation of the electrophotographic photoreceptor is small in a higher-speed, higher-resolution electrophotographic process. all right. On the other hand, when the contact angle of the electrophotographic photosensitive member was less than 100 degrees, the dots of the output image were not reproduced, and no dots could be confirmed. Further, it was found that the potential fluctuation of the electrophotographic photoreceptor greatly deteriorated as the temperature fell below 100 degrees, and it was found that the value of 100 degrees was used as the threshold value.

Although the reason for this is not clear, it is supposed that the contact angle of the electrophotographic photosensitive member with respect to pure water has a correlation with the releasability of the toner. Charged products, toner, paper, etc. are liable to adhere to the surface due to repeated use, causing deterioration of the electrophotographic photosensitive member and affecting the durability of the electrophotographic photosensitive member. May have some relationship with the size of

As the electrophotographic photosensitive member used in the present invention, a laminated electrophotographic photosensitive member obtained by sequentially laminating a charge generation layer and a charge transport layer on a conductive support is used.

Further, an inverted electrophotographic photosensitive member in which a charge transport layer and a charge generating layer are sequentially laminated on a support may be used. Further, an overcoat layer may be formed on the laminated electrophotographic photosensitive member or the inverse electrophotographic photosensitive member. May be provided.

[0015] Between the conductive support and the photosensitive layer, a coating of structural defects of the support, improvement of adhesion between the photosensitive layer and the support, protection against electrical destruction of the photosensitive layer, improvement of chargeability, support of the support, A conductive layer may be provided for the purpose of improving the charge injecting property from the substrate into the photoconductive layer.

The support used in the present invention may be any one having conductivity, such as metals such as aluminum and stainless steel, aluminum alloys and alloys such as indium oxide-tin oxide, and coating layers of these metals and alloys. For example, a cylindrical cylinder and a film of plastic having a conductive particle, paper or plastic impregnated with conductive particles, plastic having a conductive polymer, and the like are used.

The conductive particles dispersed in the conductive layer are zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide, antimony and tantalum-doped tin oxide and zirconium oxide, respectively. And conductive metal oxides, metal sulfides such as barium sulfate, carbon black and the like, or particles containing these, among which tin oxide, titanium oxide, barium sulfate and antimony oxide are preferred.
The average particle size is preferably from 0.01 to 0.5 μm, particularly preferably from 0.02 to 0.3 μm. The resin for dispersing the conductive fine powder can be appropriately selected from those which are not eluted by the solvent of the coating liquid for the barrier layer or the photosensitive layer directly applied on the conductive layer and used. In general, when the average particle diameter of the filler is small, dispersion becomes difficult and reaggregation becomes easy. However, a filler having excellent dispersibility is used. The content of the filler is 1.0 to 9 with respect to the conductive layer.
0 mass% is preferable, and especially 5.0 to 80 mass% is preferable.

As the resin used for the conductive layer, for example, phenol resin, polyurethane, polyamide, polyimide, polyamide imide, polyamic acid, polyvinyl acetal, epoxy resin, acrylic resin, melamine resin or polyester is preferable. These resins may be used alone or in combination of two or more. These resins have good adhesiveness to the support, improve the dispersibility of the filler, and have good solvent resistance after film formation. Among the above resins, phenol resins and polyurethanes are particularly preferred.

In order to improve the dispersibility of the filler, the surface of the filler may be treated with a treating agent such as a coupling agent (a silane coupling agent or a titanium coupling agent) or a silicone oil. Further, the treatment agent may be contained in a binder of the conductive layer.

The thickness of the conductive layer is preferably 0.1 to 30 μm, particularly preferably 0.5 to 20 μm. Further, the volume resistivity of the conductive layer is preferably 10 ¹³ Ω · cm or less, particularly preferably 10 Ω · cm or more and 10 ¹² Ω · cm or less. In the present invention, the volume resistivity is obtained by coating a conductive layer to be measured on an aluminum plate, further forming a gold thin film on the conductive layer, and measuring the current flowing between both electrodes of the aluminum plate and the gold thin film by pA. It was determined by measuring with a meter.

A leveling agent can be added to the conductive layer in order to enhance the surface properties of the conductive layer.

Depending on the kind of the material for the photosensitive layer, free carriers may be injected from the conductive layer into the photosensitive layer, which lowers the charging ability of the electrophotographic photosensitive member and greatly affects image characteristics. In such a case, if necessary, an intermediate layer having an electric barrier property (for example, a suitable resin thin film) is provided between the conductive layer and the photosensitive layer to effectively suppress the injection of the free carrier. Can be. As the intermediate layer, for example, polyvinyl alcohol, polyvinyl methyl ether, polyacrylic acids, methyl cellulose, ethyl cellulose, polyglutamic acid, casein, water-soluble resin such as starch, polyamide, polyimide, polyamide imide, polyamide acid, melamine resin, epoxy resin , A resin such as polyurethane or polyglutamic acid ester can be used. In particular, polyamide is preferable as the intermediate layer in terms of coating properties, adhesion, solvent resistance, electrical barrier properties, resistance, and the like. As the polyamide, a low-crystalline or non-crystalline copolymer nylon which can be applied in a solution state is suitable. The thickness of the intermediate layer is 0.1-2.
0 μm is preferred.

The charge generating materials used in the present invention include selenium-tellurium, pyrylium, thiapyrylium dyes, phthalocyanines, anthantrones, dibenzopyrene quinones, trisazo, cyanine, disazo, monoazo, indigo, quinacridone and asymmetric quinocyanine. Each of the following pigments. Further, as the phthalocyanine, aluminum chlorophthalocyanine, chloroindium phthalocyanine, oxyvanadyl phthalocyanine,
Examples thereof include metal phthalocyanines such as hydroxygallium phthalocyanine, chlorogallium phthalocyanine, magnesium phthalocyanine, and oxytitanium phthalocyanine, and metal-free phthalocyanines. Phthalocyanine greatly differs in sensitivity and other electrophotographic characteristics depending on its crystal structure, and its structure can be confirmed by X-rays or the like.

As the binder resin for the charge generation layer, various resins can be used, and specifically, for example, polycarbonate resin, polyester resin, polyarylate resin, butyral resin, polystyrene resin, polyvinyl acetal resin, diallyl phthalate resin, acrylic resin Resin, methacrylic resin, vinyl acetate resin, phenol resin, silicone resin, polysulfone resin, styrene-butadiene copolymer resin, alkyd resin, epoxy resin, urea resin, vinyl chloride-vinyl acetate copolymer resin, etc. Is not limited to these.

As the dispersion solvent, alcohols, sulfoxides, ketones, ethers, esters, aliphatic halogenated hydrocarbons or aromatic compounds can be used.

The charge generation layer comprises a charge generation material,
A homogenizer, ultrasonic dispersion, a ball mill, a vibrating ball mill, a sand mill, an attritor, a roll mill, a liquid collision type high-speed disperser, and the like are dispersed uniformly with a 4.0-fold amount of a binder resin and a solvent, and a dispersion liquid is applied. Formed by drying. The thickness of the charge generation layer is preferably 5 μm or less, particularly preferably 0.01 to 0.2 μm.

Various sensitizers, antioxidants, ultraviolet absorbers, plasticizers or known charge generation materials can be added to the charge generation layer as needed.

The charge transport layer used in the present invention is formed by applying and drying a coating solution in which a charge transport material and a binder resin are dissolved in a solvent. Examples of the charge transport material used include a triarylamine compound, a hydrazone compound, a stilbene compound, a pyrazoline compound, an oxazole compound, a triallylmethane compound, and a thiazole compound. Specific examples of the binder resin include acrylic resins such as polymethyl methacrylate and styrene-acryl copolymer, polystyrene, low molecular weight polypropylene, styrene-butadiene rubber, ethylene-vinyl acetate copolymer, vinyl chloride, and acetic acid. Vinyl and their copolymers, petroleum resins, saturated alkyl polyester resins, polyethylene terephthalate resins, polybutylene terephthalate resins, aromatic polyester resins such as polyarylate resins, polyacetals, polycarbonates, polyether sulfones,
Examples thereof include polysulfone, polyphenylene sulfide, and polyetheretherketone.

Further, an antioxidant, an ultraviolet absorber, a plasticizer, or a known charge transport material can be added to the charge transport layer as needed.

FIG. 1 shows a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the 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 electrophotographic photosensitive member 1 is uniformly charged at a predetermined positive or negative potential on its peripheral surface by the primary charging means 3, and then is exposed from exposure means (not shown) such as slit exposure or laser beam scanning exposure. The exposure light 4 intensity-modulated according to the time-series electric digital image signal of the target image information to be output is received. In this way, an electrostatic latent image corresponding to the target image information is sequentially formed on the peripheral surface of the electrophotographic photosensitive member 1.

The formed electrostatic latent image is then developed.
Is transferred to the transfer material 7 taken out of the paper supply unit (not shown) between the electrophotographic photosensitive member 1 and the transfer means 6 in synchronization with the rotation of the electrophotographic photosensitive member 1 and fed. The toner image formed and carried on the surface of the photoconductor 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 electrophotographic photosensitive member, introduced into the image fixing means 8 and subjected to image fixing, thereby being printed out of the apparatus as an image formed product (print, copy). Be out.

The surface of the electrophotographic photoreceptor 1 after the image transfer is cleaned and cleaned by removing the untransferred toner by a cleaning means 9, and is further subjected to a charge removal treatment by a pre-exposure light 10 from a pre-exposure means (not shown). After that, it is repeatedly used for image formation. 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, among the above-described components such as the electrophotographic photosensitive member 1, the primary charging means 3, the developing means 5, and the cleaning means 9, a plurality of components are housed in a container and integrally combined as a process cartridge. The process cartridge may be configured to be detachable from an electrophotographic apparatus body 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 with the electrophotographic photosensitive member 1 to form a cartridge, and is attached to and detached from the apparatus main body by using a guide unit 12 such as a rail of the apparatus main body. A flexible process cartridge 11 can be provided.

In the case where the electrophotographic apparatus is a copying machine or a printer, the exposure light 4 is reflected light or transmitted light from the original, or the original is read by a sensor, converted into a signal, and a laser beam is emitted in accordance with the signal. Beam scanning, LED
The light is emitted when the array is driven or the liquid crystal shutter array is driven.

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,
The present invention can be widely applied to electrophotographic application fields such as CRT printers, LED printers, faxes, liquid crystal printers, and laser plate making.

[0038]

The present invention will be described in more detail with reference to the following examples. In the examples, “parts” means “parts by mass”.

(Example 1) Length: 260.5 mm, diameter: 3
An aluminum cylinder (JISA3003 aluminum alloy) having 0 mm, a cylinder part thickness of 0.7 mm, a maximum surface roughness of 5.0 μm, and an average surface roughness of 1.0 μm was prepared.

60 parts of powder composed of barium sulfate particles having a tin oxide coating layer (trade name: Pastoran PC1, manufactured by Mitsui Mining & Smelting Co., Ltd.), titanium oxide (trade name: TITA)
NIX JR, manufactured by Teica Co., Ltd.) 60 parts, resol type phenol resin (trade name: Phenolite J-325, manufactured by Dainippon Ink and Chemicals, Inc., solid content 70%) 70 parts,
10 parts of silicone oil (trade name: SH28PA, manufactured by Toray Silicone Co., Ltd.), 10 parts of silicone resin (trade name: Tospearl 120, manufactured by Toshiba Silicone Co., Ltd.), 2-
A solution consisting of 60 parts of methoxy-1-propanol / 60 parts of methanol was dispersed in a ball mill for about 20 hours.

The conductive layer dispersion thus prepared was applied onto the above-mentioned aluminum cylinder by an immersion method, and was heated and cured at 140 ° C. for 30 minutes to form a resin layer having a thickness of 15 μm. The surface roughness Rmax of the resin layer measured at this time was 0.7 μm.
The roughness Rmax is based on JIS B0601.

Next, 10 parts of a copolymerized nylon resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) and 10 parts of methoxymethylated 6 nylon resin (trade name: Toresin EF-30)
T, manufactured by Teikoku Chemical Co., Ltd.)
A solution dissolved in a mixed solution of 200 parts of n-butanol was applied onto the resin layer by dip coating, and dried by heating at 90 ° C. for 10 minutes to form an intermediate layer having a thickness of 0.62 μm.

Next, Cu represented by the following structural formula (1)
Bragg angle in Kα characteristic X-ray diffraction (2θ ± 0.
2 () is 9.0 (, 14.2 ° 23.9 ° and 27.1)
(6 parts of an oxytitanium phthalocyanine pigment having a strong peak at,

[0044]

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A mixed solution of 5 parts of polyvinyl butyral resin (trade name: Eslec BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 180 parts of cyclohexanone was dispersed in a sand mill for 3 hours, and 250 parts of ethyl acetate was added to charge the mixture. A coating liquid for a generating layer was prepared. This coating solution was applied onto the above-prepared intermediate layer by dip coating, and dried by heating at 90 ° C. for 10 minutes to form a charge generating layer having a thickness of 0.06 μm.

Next, 40 parts of a charge transporting material represented by the following structural formula (2):

[0047]

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Polycarbonate (trade name: Iupilon Z)
-400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) and 45 parts of a silicone-modified polycarbonate represented by the following structural formula (3) (viscosity average molecular weight: 40000)

[0049]

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A solution prepared by dissolving chlorobenzene in 350 parts of chlorobenzene was applied onto the above-mentioned charge generating layer by dip coating.
For 1 hour to form a charge transport layer having a thickness of 27 μm.

At this time, the contact angle of the surface layer with pure water is
It was 104.8 degrees when measured as follows.

<Measurement Method of Contact Angle> The contact angle was measured using pure water at normal temperature and normal humidity, and a contact angle type CA-DS manufactured by Kyowa Interface Science Co., Ltd. was used as an apparatus. The contact angle was an average value of five points on the surface of the electrophotographic photosensitive member, and was measured within one minute after the attachment of the water droplet.

Next, the evaluation will be described. As an evaluation device, an LBP “Laser Jet 4000” manufactured by Hewlett-Packard was used after being modified as follows. In the remodeling, the resolution (R) was set to real 1200 dpi, the drum rotation speed (r) was set to 1.6 (rotation / second), and the process speed was set to 151.4 mm / sec. Further, a DC bias of -620 V is applied as an applied voltage to the electrophotographic photoreceptor, and an AC of 1600 Hz / 1300 μA is further applied.
By superimposing a bias, the charging potential Vd of the surface of the electrophotographic photosensitive member at the time of non-irradiation of the laser beam is -600V.
It was made to become.

The above electrophotographic photoreceptor is loaded in such an electrophotographic apparatus, and the charged potential Vd of the dark portion when laser light is not irradiated under normal temperature and normal humidity (23 ° C./50% RH) environment, laser light irradiation The potential Vl at the time was measured. The amount of laser light was 0.3 μJ / cm ² . Table 1 shows the results.

Further, using an undurable electrophotographic photosensitive member,
A halftone image of isolated dots as shown in FIG. 2 was printed. The image at that time was observed with a magnifying glass of 50 magnifications, and
The dot reproducibility (scatter, connection of dots, etc.) was evaluated. Table 1 shows the results.

Further, using a modified Hewlett-Packard LBP “Laser Jet 4000”,
The continuous durability of 10,000 sheets was performed in an environment of 3 ° C./55% RH. Letter size paper (75 g / m ² ) manufactured by Xerox Co., Ltd. was used as the evaluation paper. Table 1 shows the potential results after the endurance and the image results after the endurance (shading of image density).

(Example 2) Instead of the charge transport layer coating solution used in Example 1, the following materials: 40 parts of a charge transport material of the structural formula (2): polycarbonate (Iupilon Z-400, Mitsubishi Gas Chemical Co., Ltd.) Co., Ltd.) 50 parts Comb-type silicone (Aron GS101CP, manufactured by Toa Gosei Chemical Industry Co., Ltd.) 0.9 parts Coating liquid for a charge transport layer is prepared using 400 parts of chlorobenzene to form a charge generation layer. did. At this time, the thickness of the charge generation layer was 24 μm. The contact angle of the surface of the electrophotographic photosensitive member with respect to pure water was 105.5 degrees. This electrophotographic photosensitive member was used in Example 1
Was evaluated in the same way as Table 1 shows the results.

(Example 3) In place of the charge transport layer coating solution used in Example 1, the following materials: 40 parts of a charge transport material of the structural formula (2): polycarbonate (Iupilon Z-400, Mitsubishi Gas Chemical Co., Ltd.) Co., Ltd.) 45 parts ・ 5 parts of silicone-modified polycarbonate of structural formula (3) (viscosity average molecular weight 40,000) ・ 0.9 parts of comb silicone (Aron GS101CP, manufactured by Toa Gosei Chemical Industry Co., Ltd.) 0.9 parts ・ 340 parts of chlorobenzene To prepare a charge transport layer coating solution, thereby forming a charge generation layer. At this time, the thickness of the charge generation layer was 29 μm. The contact angle of the surface of the electrophotographic photosensitive member with respect to pure water was 113.4 degrees. This electrophotographic photosensitive member was used in Example 1
Was evaluated in the same way as Table 1 shows the results.

Example 4 Instead of the dispersion for a charge generation layer used in Example 1, CuK represented by the structural formula (1) was used.
Bragg angle in α-characteristic X-ray diffraction (2θ ± 0.2 ()
5.4 parts of an oxytitanium phthalocyanine pigment having a strong peak at 9.0 (, 14.2 °, 23.9 ° and 27.1 (), 0.6 part of a material represented by the following structural formula (4), and oxidation 1.1 parts of an inhibitor (Antage Crystal, manufactured by Kawaguchi Chemical Co., Ltd.) is 5 parts of polyvinyl butyral resin (trade name: Esrec BX-1, manufactured by Sekisui Chemical Co., Ltd.)
After dispersion with a liquid collision type high-speed dispersion device together with a mixed solution consisting of 180 parts of cyclohexanone, 250 parts of ethyl acetate was added to prepare a coating liquid for a charge generation layer. This charge generation layer dispersion was used for forming the charge generation layer. At this time, the thickness of the charge generation layer was 0.05 μm.

[0060]

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Further, instead of the coating liquid for the charge transport layer used in Example 1, the following materials: 72 parts of the charge transport material of the structural formula (2); 8 parts of the charge transport material of the following structural formula (5): 85 parts of polycarbonate (Iupilon Z-400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) 10 parts of silicone-modified polycarbonate of the following structural formula (6) (viscosity average molecular weight 400000) 10 parts of silicone-modified polycarbonate of structural formula (3) (viscosity average) Molecular weight 40000) 5 parts ・ Comb type silicone (Aron GS101CP, manufactured by Toa Gosei Chemical Industry Co., Ltd.) 1.8 parts ・ 800 parts of chlorobenzene is used to prepare a charge transport layer coating liquid to form a charge transport layer. did. At this time, the thickness of the charge transport layer was 27 μm. The contact angle of the electrophotographic photosensitive member surface with pure water was 108.4 degrees. This electrophotographic photosensitive member was used in Example 1
Was evaluated in the same way as Table 1 shows the results.

[0062]

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[0063]

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Example 5 Instead of the charge transport layer coating solution used in Example 4, the following materials: 81 parts of the charge transport material of the structural formula (2) 9 parts of the charge transport material of the structural formula (5) -50 parts of polyarylate of the following structural formula (7) (viscosity average molecular weight 40000)-40 parts of polycarbonate (Iupilon Z400, manufactured by Mitsubishi Gas Chemical Co., Ltd.)-10 parts of silicone-modified polycarbonate of structural formula (6)-10 parts of comb silicone (Aron GS101CP, manufactured by Toa Gosei Chemical Industry Co., Ltd., 1.9 parts; chlorobenzene, 470 parts; methylal, 252 parts) was used to prepare a charge transport layer coating solution to form a charge transport layer. The thickness of the layer was 21 μm, and the contact angle of the surface of the electrophotographic photosensitive member with pure water was 112.1 °.
Was evaluated in the same way as Table 1 shows the results.

[0065]

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Example 6 Instead of the charge transport layer coating solution used in Example 4, the following materials: 81 parts of the charge transport material of the structural formula (2) 9 parts of the charge transport material of the structural formula (5) -50 parts of polyarylate of structural formula (7)-40 parts of polycarbonate (Iupilon Z200, manufactured by Mitsubishi Gas Chemical Co., Ltd.)-10 parts of silicone-modified polycarbonate of structural formula (6)-Comb type silicone (Aron GS101CP, Toa Gosei Chemical) A charge transport layer coating solution was prepared using 1.9 parts, 470 parts of chlorobenzene, and 252 parts of methylal to form a charge transport layer. At this time, the thickness of the charge transport layer was 24 μm. The contact angle of the surface of the electrophotographic photosensitive member with respect to pure water was 107.3 degrees. This electrophotographic photosensitive member was used in Example 1
Was evaluated in the same way as Table 1 shows the results.

(Example 7) Instead of the charge transport layer coating solution used in Example 4, a charge transport layer coating solution was prepared by the following method to form a charge transport layer. At this time, the thickness of the charge transport layer was 20 μm. The contact angle of the surface of the electrophotographic photosensitive member with respect to pure water was 121.2 degrees. This electrophotographic photosensitive member was evaluated in the same manner as in Example 1. Table 1 shows the results.

<Method of preparing coating solution for charge transport layer> 6.7 parts of charge transport material of structural formula (2) 2.8 parts of charge transport material of structural formula (5) Polycarbonate (Iupilon Z400, Mitsubishi Gas Chemical) 9.5 parts were dissolved in 30 parts of chlorobenzene and 20 parts of methylal.

Further, 1 part of a fluororesin powder (trade name: Lubron L-2, manufactured by Daikin Industries, Ltd.) was added to chlorobenzene 10
The liquid dispersed in the part by sand mill dispersion was added to the above-mentioned solution. At this time, in order to stabilize the dispersibility of the powder, 0.05 part of a surfactant (trade name: GF-300, manufactured by Toagosei Co., Ltd.) as a dispersing aid was added (fluorine resin powder content 5 mass%).

(Example 8) Instead of the charge transport layer coating liquid used in Example 1, the following materials: 40 parts of the charge transport material of the structural formula (2) Polycarbonate (Iupilon Z-400, Mitsubishi Gas Chemical Co., Ltd.) Co., Ltd.) 50 parts 1 part of silicone-modified polycarbonate of structural formula (3) (viscosity average molecular weight 40,000) 1 part 360 parts of chlorobenzene was used to prepare a charge transport layer coating solution to form a charge generation layer. At this time, the thickness of the charge generation layer was 24 μm. The contact angle of the surface of the electrophotographic photosensitive member with respect to pure water was 101.1 degrees. This electrophotographic photosensitive member was used in Example 1
Was evaluated in the same way as Table 1 shows the results.

(Example 9) Instead of the aluminum cylinder used in Example 1, the length was 257.0 mm and the diameter was 2
An electrophotographic photoreceptor was prepared in the same manner as in Example 4 using an aluminum cylinder having a thickness of 4 mm, a cylinder thickness of 0.7 mm, a maximum surface roughness of 5.0 μm, and an average surface roughness of 1.0 μm. The production conditions were the same as in Example 1, and the contact angle of the electrophotographic photosensitive member surface with pure water was 107.5 degrees.

This electrophotographic photosensitive drum was manufactured by Canon L
The BP “LBP-350” was loaded into an evaluation machine modified as follows, and evaluated in the same manner as in Example 1. In the modification, the resolution (R) was set to real 1200 dpi, the number of rotations (r) of the drum was set to 1.6 (rotation / second), and the process speed was set to 120.6 mm / sec. The charging conditions and the amount of laser light were set so that Vd = -600 V and Vl = -180 V. Table 1 shows the results.

Example 10 Instead of the aluminum cylinder used in Example 1, the length was 288 mm and the diameter was 4 mm.
An electrophotographic photoreceptor was produced in the same manner as in Example 4 using an aluminum cylinder having a thickness of 6.7 mm, a cylinder thickness of 1.0 mm, a maximum surface roughness of 5.0 μm, and an average surface roughness of 1.0 μm. The production conditions were the same as in Example 1, and the contact angle of the surface of the electrophotographic photosensitive member with respect to pure water was 107.9 degrees.

This electrophotographic photosensitive drum was manufactured by Canon L
The BP “LBP-2040” was loaded into an evaluation machine modified as follows, and evaluated in the same manner as in Example 1. In the remodeling, the resolution (R) was set to real 1200 dpi, the drum rotation speed (r) was set to 1.6 (rotation / second), and the process speed was set to 234.7 mm / sec. The charging conditions and the amount of laser light were set so that Vd = −550 V and Vl = −180 V. Table 1 shows the results.

(Example 11) Instead of the aluminum cylinder used in Example 1, a length of 360 mm and a diameter of 80 mm were used.
An electrophotographic photosensitive member was produced in the same manner as in Example 4 using an aluminum cylinder having a thickness of 1.0 mm, a cylinder portion thickness of 1.0 mm, a maximum surface roughness of 5.0 μm, and an average surface roughness of 1.0 μm. The manufacturing conditions were the same as in Example 1, and the contact angle of the surface of the electrophotographic photosensitive member with respect to pure water was 108.6 degrees.

This electrophotographic photosensitive drum was loaded into an evaluation machine modified from a Canon color copying machine “CLC-500” as follows, and evaluated in the same manner as in Example 1. In the remodeling, the resolution (R) was set to real 1200 dpi, the drum rotation speed (r) was set to 1.6 (rotation / second), and the process speed was set to 402.4 mm / sec. The charging conditions and the amount of laser light were set so that Vd = −730 V and Vl = −180 V. Table 1 shows the results.

(Example 12) The evaluator used in Example 1 was modified as follows. For remodeling, resolution (R) is real 1
440 dpi, the drum rotation speed (r) is 1.6 (rotation / second), and the process speed is 151.4 mm / sec.
c. The same electrophotographic photosensitive drum as in Example 3 was loaded into this evaluator, and evaluation was performed in the same manner as in Example 1. Regarding the reproducibility of one dot, a similar halftone image was printed with one square in FIG. 2 being 18 μm. Table 1 shows the results.

(Example 13) The evaluation machine used in Example 1 was modified as follows. For remodeling, resolution (R) is real 1
200 dpi, the drum rotation speed (r) is 1.9 (rotation / sec), and the process speed is 179.0 mm / sec.
c. The same electrophotographic photosensitive drum as in Example 3 was loaded into this evaluator, and evaluation was performed in the same manner as in Example 1. Table 1 shows the results.

(Example 14) The evaluation machine used in Example 1 was modified as follows. For remodeling, resolution (R) is real 1
440 dpi, the drum rotation speed (r) is 1.9 (rotation / second), and the process speed is 179.0 mm / sec.
c. The same electrophotographic photosensitive drum as in Example 3 was loaded into this evaluator, and evaluation was performed in the same manner as in Example 1. Regarding the reproducibility of one dot, a similar halftone image was printed with one square in FIG. 2 being 18 μm. Table 1 shows the results.

(Comparative Example 1) Instead of the charge transport layer coating solution used in Example 1, the following materials: 40 parts of a charge transport material of the structural formula (2): polycarbonate (Iupilon Z-400, Mitsubishi Gas Chemical Co., Ltd.) Co., Ltd.) 50 parts chlorobenzene 450 parts to prepare a charge transport layer coating liquid to form a charge generation layer. At this time, the thickness of the charge generation layer was 24 μm. The contact angle of the surface of the electrophotographic photosensitive member with respect to pure water was 92.8 degrees. This electrophotographic photosensitive member was evaluated in the same manner as in Example 1. Table 1 shows the results.

(Comparative Example 2) Instead of the charge transport layer coating solution used in Example 1, the following materials: 40 parts of the charge transport material of the structural formula (2); polyarylate of the structural formula (7) (viscosity average) A coating liquid for a charge transport layer was prepared using 50 parts of 450 parts of chlorobenzene to form a charge generation layer. At this time, the thickness of the charge generation layer was 24 μm. The contact angle of the surface of the electrophotographic photosensitive member with respect to pure water was 85.1 degrees. This electrophotographic photosensitive member was evaluated in the same manner as in Example 1. Table 1 shows the results.

(Comparative Example 3) Instead of the charge transport layer coating solution used in Example 1, the following materials: 40 parts of the charge transport material of the following structural formula (8): polyarylate of the structural formula (7) (viscosity) A coating liquid for a charge transport layer was prepared using 50 parts of chlorobenzene and 420 parts of chlorobenzene to form a charge generation layer. At this time, the thickness of the charge generation layer was 21 μm. The contact angle of the surface of the electrophotographic photosensitive member with respect to pure water was 80.5 degrees. This electrophotographic photosensitive member was evaluated in the same manner as in Example 1. Table 1 shows the results.

[0083]

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(Comparative Example 4) The following materials were used instead of the coating solution for the charge transport layer used in Example 1. 40 parts of a charge transport material having the following structural formula (9): Polycarbonate (Iupilon Z-200, Mitsubishi Gas Chemical Co., Ltd.) Coating solution for a charge transport layer was prepared using 50 parts of 380 parts of chlorobenzene to form a charge generation layer. At this time, the thickness of the charge generation layer was 23 μm. The contact angle of the surface of the electrophotographic photosensitive member with respect to pure water was 71.2 degrees. This electrophotographic photosensitive member was evaluated in the same manner as in Example 1. Table 1 shows the results.

[0085]

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(Comparative Example 5) Instead of the charge transport layer coating solution used in Example 1, the following materials: 23 parts of a charge transport material of the structural formula (2): polycarbonate (Iupilon Z-200, Mitsubishi Gas Chemical Co., Ltd.) Co., Ltd.) 50 parts • 300 parts of chlorobenzene was used to prepare a charge transport layer coating solution to form a charge generation layer. At this time, the thickness of the charge generation layer was 23 μm. The contact angle of the surface of the electrophotographic photosensitive member with respect to pure water was 97.9 degrees. This electrophotographic photosensitive member was evaluated in the same manner as in Example 1. Table 1 shows the results.

[0087]

[Table 1] Dot reproducibility ◎ ・ ・ ・ 1 dot can be confirmed clearly ○ ・ ・ ・ There is some scatter, but 1 dot is isolated △ ・ ・ ・ Slightly scattered, 1 dot is isolated but connected × × 1 dot appears to be connected × × ... 1 dot cannot be confirmed

As is clear from the results in Table 1, when an electrophotographic photosensitive member having a contact angle of 100 ° or more with pure water on the surface of the electrophotographic photosensitive member was used, an isolated dot of 1200 dpi was reproduced. It turned out that it was excellent in image formation. On the other hand, when an electrophotographic photosensitive member having a contact angle of 97.9 degrees or less was used, no isolated dot was formed.

Regarding the fluctuation of the potential of the electrophotographic photosensitive member, the fluctuation of the potential was small and the durability image was good for the electrophotographic photosensitive member having a contact angle of 100 ° or more.
It was found that in the electrophotographic photoreceptor having a temperature of 97.9 degrees or less, the potential fluctuation rapidly increased, and as the contact angle was further reduced, the potential fluctuation significantly deteriorated.

[0090]

According to the present invention, an electrophotographic photoreceptor which does not deteriorate dot reproducibility even in a higher-speed and higher-resolution electrophotographic process and does not deteriorate the potential fluctuation of the electrophotographic photoreceptor due to durability. And a process cartridge and an electrophotographic apparatus having the same.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus including a process cartridge having an electrophotographic photosensitive member according to the present invention.

FIG. 2 At 1200 dpi (21 μm × 21 μ for one cell)
It is a figure which shows the 1 dot formation method of m).

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Axis 3 Charging means 4 Exposure light 5 Developing means 6 Transfer means 7 Transfer material 8 Fixing means 9 Cleaning means 10 Pre-exposure light 11 Process cartridge 12 Guide means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Norimichi Miki 3-30-2 Shimomaruko, Ota-ku, Tokyo Within Canon Inc. (72) Inventor Hirotoshi Uesugi 30-30-2 Shimomaruko, Ota-ku, Tokyo Canon F term (reference) 2H068 AA28 AA34 AA35 FA27

Claims (4)

[Claims] 1. The resolution in an electrophotographic process is R
(Dpi), the number of rotations of the electrophotographic photosensitive member is r (rotation / second)
In the electrophotographic photoreceptor used under the electrophotographic process conditions of R ≧ 1200 and R · r ≧ 1.9 × 10 ³ , the electrophotographic photoreceptor is provided with a photosensitive layer on a conductive support. An electrophotographic photoreceptor, wherein a contact angle of the surface of the photosensitive layer with respect to pure water is 100 degrees or more. 2. The electrophotographic photoreceptor according to claim 1, wherein said photosensitive layer comprises at least a charge generation layer and a charge transport layer. 3. A charging unit for charging the electrophotographic photosensitive member according to claim 1 or 2,
At least one means selected from the group consisting of a developing means for developing the electrophotographic photosensitive member on which the electrostatic latent image is formed with toner, and a cleaning means for collecting residual toner on the electrophotographic photosensitive member after the transfer step A process cartridge which is supported integrally with the electrophotographic apparatus and is detachable from the main body of the electrophotographic apparatus. 4. An electrophotographic photosensitive member according to claim 1, a charging means for charging the electrophotographic photosensitive member, and an exposure to the charged electrophotographic photosensitive member to form an electrostatic latent image. An electrophotographic apparatus comprising: an exposure unit; a developing unit that develops an electrophotographic photosensitive member on which an electrostatic latent image is formed with toner; and a transfer unit that transfers a toner image on the electrophotographic photosensitive member onto a transfer material. apparatus.