JP5258409B2 - Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photoreceptor containing a binder resin and a charge transport material having a specific structure in a photosensitive layer, a process cartridge having the electrophotographic photoreceptor, and an electrophotographic apparatus.

  In recent years, photoconductors used in electrophotographic technology have been practically used as photoconductive materials because of their advantages such as easy film formation and stable production at low cost. The research and development is still active. Among organic photoconductors, the functionally separated type organic photoconductor having a charge generation layer and a charge transport layer laminated exhibits good electrophotographic characteristics, and further, a suitable material is selected from a wide range of organic materials for each layer. As a result, it has become the mainstream and put to practical use. And the improvement of the characteristic has been achieved about the high sensitivity as an organic photoconductor for electrophotography, and durability with respect to mechanical deterioration.

  However, on the other hand, further improvements are desired in terms of image quality, durability against electrical deterioration, storage stability of the photoreceptor, and the like.

  For example, with regard to image quality, with the colorization of an output image, uniformity such as density and color tone in one output image, and stability when these are continuously output are required.

  In particular, there is a phenomenon in which only the portion irradiated with light in one output image has a density (positive ghost image) in the halftone image of the next rotation, or a phenomenon in which the density becomes low (negative ghost image). It is a problem.

  Ghost images are thought to be caused by carrier retention (memory phenomenon) in the electrophotographic photosensitive member, and a method of adding an acceptor compound or an electron transport material to the charge generation layer is disclosed as a method for improving these. (Patent Documents 1 to 5).

  In addition, regarding electrical degradation, there is a need for improvement in photo memories that cause carriers to stay in the light-irradiated areas and cause a potential difference from the areas not irradiated with light, which impairs image reproducibility. . With the recent increase in sensitivity of photoconductors, it is important to improve photo memories in the current situation that photo memories are likely to be generated by light leaking from the outside.

  For improving photo memory, a method of adding a specific additive to the charge transport layer (Patent Document 6) and a method of using a resin binder having a specific structure in the charge transport layer (Patent Document 7) have been proposed.

  With respect to the storage stability of the photoreceptor, there is a problem that a low molecular compound such as a charge transport material contained in the photosensitive layer is deposited while the photoreceptor is stored. With the recent demand for higher sensitivity, low molecular weight compounds such as charge transport materials are often added in relatively large amounts. As a result, low molecular weight compounds can be obtained when the photoreceptor is stored for a long period of time. There is a tendency to be easily precipitated.

  As countermeasures, a method of curing a charge transporting monomer to form a charge transport layer (Patent Document 8) and a method using a polymer charge transport material (Patent Document 9) are disclosed.

  Patent Documents 10 to 17 disclose a technique in which a charge transport material is a compound having a triarylamine structure.

Further, Non-Patent Document 1 discloses a design guideline for a general high mobility charge transport material.
Japanese Patent Application Laid-Open No. 07-104495 JP 2000-292946 A JP 2002-296817 A JP-A-2005-208618 JP-A-2005-208619 Japanese Patent Application Laid-Open No. 08-320583 JP-A-10-020514 JP 2000-066424 A Japanese Patent Laid-Open No. 08-248649 JP-A-51-93224 JP 52-4242 A JP-A-61-2228450 JP-A-62-208054 JP-A-62-283341 JP-A-62-283341 JP-A-2-183259 JP 2005-215264 A Proceedings of the 49th Technical Seminar of the Imaging Society of Japan

  However, Patent Documents 10 to 16 disclose a charge transport material having a triarylamine structure, but do not disclose a charge transport material having an alkyl group having 6 to 10 carbon atoms as a substituent.

  Further, Patent Document 17 discloses a charge transport material having an aliphatic group having 4 or more carbon atoms, but only discloses the case where the charge transport material is applied to a single layer photoreceptor. Regarding the effect, there is no description about the effect of suppressing ghost, reducing photo memory, and preventing precipitation during long-term storage.

  Non-Patent Document 1 discloses a design guideline for a conventional general high mobility charge transport material.

  Specifically, Non-Patent Document 1 describes that it is necessary to design a molecular structure reflecting the following four points as a design guideline for a high mobility charge transport material. Specifically, (1) effective orbital spread and overlap, (2) avoidance of formation of structural traps, (3) uniform charge density distribution, (4) molecular structure considering dipole efficiency 4 points of the molecular design.

  Also in this non-patent document 1, introduction of an alkyl group having 6 to 10 carbon atoms into the structure of the charge transport material is contrary to the above-described general design guidelines for high mobility charge transport materials. It has not been.

  That is, it has been common knowledge to design a charge transport material according to the above design guidelines. The charge transport material having an alkyl group having 6 to 10 carbon atoms in the structure of the present invention is said to be unable to ensure effective orbital expansion and overlap of (1) due to its steric hindrance. .

  An object of the present invention is to provide an electrophotographic photosensitive member that solves the above-described problems, has an image quality that does not cause ghosting, does not generate photo memory, and is stable for long-term storage. That is.

In accordance with the present invention, an electrophotographic photosensitive member having a photosensitive layer on an electroconductive substrate, the photosensitive layer contains a resin binder, and that electric charge transport material having an alkyl group having 6 to 10 carbon atoms, a And
The charge transport material having an alkyl group having 6 to 10 carbon atoms is at least one of the compounds represented by the following general formula (1) or (2). .

Further, according to the present invention, that electrostatic charge transport material having an alkyl group of the number of 6 to 10 carbon atoms, an electrophotographic photosensitive member is a compound represented by the following formula (1) is provided.

(In the above formula (1), R ₁₀₁ ~R ₁₂₈ is hydrogen atom, substituted showing also alkyl groups. Further, at least two of R ₁₀₁ to R _120, the number 6 to 10 carbon (However, it does not have two or more alkyl groups having 6 to 10 carbon atoms on the same benzene ring. X has a structure selected from the following group.)

Further, according to the present invention, the that electrostatic charge transport material having an alkyl group having 6 to 10 carbon atoms, an electrophotographic photosensitive member is a compound represented by the following formula (2) is provided.

(In the above formula (2), R _{201 to} R ₂₂₀ represent a hydrogen atom or an alkyl group which may have a substituent, and at least two are alkyl groups having 6 to 10 carbon atoms. (It does not have two or more alkyl groups having 6 to 10 carbon atoms on the ring at the same time. Y has a structure selected from the following group.)

(The above R _{1 to} R ₃ represent _a methyl group or an ethyl group.)
Furthermore, according to the present invention, there are provided a process cartridge and an electrophotographic apparatus comprising the electrophotographic photosensitive member.

  According to the present invention, an electrophotographic photosensitive member having image quality that does not cause ghosting, no photo memory, and stable for long-term storage, and a process cartridge having the electrophotographic photosensitive member are provided. In addition, an electrophotographic apparatus can be provided.

  Hereinafter, the electrophotographic photoreceptor of the present invention will be described in detail.

  As described above, the electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member having a photosensitive layer on a conductive support, and the photosensitive layer has a resin binder and a structure represented by the following general formula (1) or (2). An electrophotographic photoreceptor comprising a charge transport material.

(In the above formula (1), R ₁₀₁ ~R ₁₂₈ is hydrogen atom, substituted showing also alkyl groups. Further, at least two of R ₁₀₁ to R _120, the number 6 to 10 carbon (However, it does not have two or more alkyl groups having 6 to 10 carbon atoms on the same benzene ring. X has a structure selected from the following group.)

(In the above formula (2), R _{201 to} R ₂₂₀ represent a hydrogen atom or an alkyl group which may have a substituent, and at least two are alkyl groups having 6 to 10 carbon atoms. (It does not have two or more alkyl groups having 6 to 10 carbon atoms on the ring at the same time. Y has a structure selected from the following group.)

(The above R _{1 to} R _{3 represent a} methyl group or an ethyl group.)
Examples of the alkyl group of R _{101 to} R ₁₂₀ in the above formula (1) and R _{201 to} R ₂₂₀ in the formula (2) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a heptyl group. Octyl group, nonyl group, decanyl group and the like.

Examples of the alkyl group of R _{121 to} R _{128 in} the above formula (1) include a methyl group, an ethyl group, a propyl group, and a butyl group.

In addition, the alkyl groups of R _{101 to} R ₁₂₈ and R _{201 to} R ₂₂₀ may have a substituent, and examples of the substituent that may have include alkyl groups such as methyl, ethyl, propyl, and butyl Can be mentioned.

  The triarylamine compounds having an alkyl group having 6 to 10 carbon atoms, which are specific examples of the repeating structural units represented by the above formulas (1) and (2), are shown in Table 1, but are limited thereto. It is not a thing.

  In addition, unless otherwise indicated, all the alkyl groups which the charge transport material of an exemplary compound, an Example, and a comparative example has are linear alkyl groups.

Among these compounds, CTM-3, CTM-6, CTM-13, CTM-16, CTM-23, CTM-26, CTM-30, CTM-33, CTM-36 and CTM-40 are preferred. Furthermore, CTM-3, CTM-13, CTM-23, CTM-30, CTM-33, and CTM-40 are particularly preferable.

  CTM-3, CTM-13, CTM-23, CTM-30, CTM-33, and CTM-40 are linear alkyls having 6 to 8 carbon atoms among the compounds represented by the above general formula (1). Corresponds to those having a group.

  Since the charge transport material of the present invention has a specific skeleton and an alkyl group having 6 to 10 carbon atoms, molecules are unlikely to gather and precipitation due to crystallization of molecules is unlikely to occur. Furthermore, since it can exist uniformly in the charge transport layer containing the resin binder regardless of the resin type, it forms micro domains (charge trap sites) of the charge transport material that is considered to be a cause of photo memory. Hateful. As a result, it is considered that ghosts caused by the memory phenomenon of the photosensitive layer are also suppressed.

  However, since it has an alkyl group having 6 to 10 carbon atoms, it is inferior in terms of sensitivity, although slightly, compared to conventional charge transport materials that do not have these substituents. However, by adjusting the ratio of the charge transport material and the resin binder in the charge transport layer and using the ratio of the charge transport material 5-10% more than the conventional one, the number of carbon atoms is 6 or more and 10 Sensitivity equivalent to that having no alkyl group is obtained.

  The charge transport materials represented by the above formulas (1) and (2) used for the charge transport layer of the electrophotographic photosensitive member of the present invention may be used alone, or the compounds of the above formulas (1) and (2) Two or more types may be mixed and used.

  The charge transport materials represented by the above formulas (1) and (2) used in the charge transport layer of the present invention are synthesized by a condensation reaction of an aryl halide and an amine compound. Examples of coupling reactions used in the synthesis include, for example, the Ullmann reaction synthesized from benzene iodides and amine compounds using a copper catalyst (Dai Organic Chemistry, vol. 16, 52 (1959) Asakura Shoten, Organic Chemistry Course. 3, 66 (1983) Maruzen, etc.). It can also be synthesized from an aryl halide and an amine compound by a method using a phosphine and a palladium compound as a catalyst in the presence of a base. Such synthetic methods are described in Tetrahedron Letters, Vol. 36, no. 21, 3609 (1995), J. MoI. AM. Chem. Soc. Vol. 120, 9722 (1998).

<Synthesis Example 1>
Below, the synthesis method of exemplary compound CTM-3 is shown as a synthesis example.

  1-iodo-4-n-hexylbenzene 10.0 g (34.7 mmol), 2,2-bis (4-aminophenyl) propane 1.78 g (7.8 mmol), o-dichlorobenzene 10 ml, copper powder 6. 6 g and 7.2 g of potassium carbonate are prepared. These were placed in a 100 ml eggplant flask equipped with a condenser and heated to reflux for 8 hours.

  After allowing to cool, filtration was performed to remove the catalyst. To the obtained filtrate, 100 ml of toluene and 100 ml of water were added, liquid separation extraction was performed, and the organic layer was separated. Furthermore, after washing the organic layer with 100 ml of water, sodium sulfate was added to the organic layer to remove moisture. Next, toluene and o-dichlorobenzene were distilled off from the resulting solution to obtain a crude product.

  The obtained crude product was purified using a silica gel column to obtain 4.87 g (yield 72%) of the charge transport material of Example Compound CTM-3.

<Synthesis Example 2>
Next, a synthesis example of exemplary compound CTM-13 is shown.

  In a 200 ml eggplant flask with a condenser tube, 10.0 g (34.7 mmol) of 1-bromo-4-n-hexylbenzene, 2.07 g (7.8 mmol) of 1,1-bis (4-aminophenyl) cyclohexane and 30 ml of o-xylene was added and stirred at room temperature for 5 minutes. Next, 373 mg (1.66 mmol) of palladium acetate, 1.34 g (6.64 mmol) of tri-tert-butylphosphine and 5.58 g (58.1 mmol) of sodium-tert-butoxide were added, and the mixture was heated to reflux for 1 hour.

  After allowing to cool, filtration was performed to remove the catalyst. To the obtained filtrate, 100 ml of toluene and 100 ml of water were added, liquid separation extraction was performed, and the organic layer was separated. Further, the organic layer was washed with 100 ml of water. After repeating this washing operation three times, sodium sulfate was added to the organic layer to remove moisture. Next, o-xylene and toluene were distilled off from the resulting solution to obtain a crude product.

  The resulting crude product was purified using a silica gel column to obtain 5.80 g (yield: 82.0%) of the charge transport material of Exemplary Compound CTM-13.

<Synthesis Example 3>
Next, the synthesis example of exemplary compound CTM-30 is shown.

  In a 200 ml eggplant flask equipped with a condenser tube, 10.0 g (30.5 mmol) of bis (4-bromophenyl) ether, 24.0 g (61.0 mmol) of a diarylamine compound having the following structure (A), and 60 ml of o-xylene were added. And stirred at room temperature for 5 minutes. Next, 548 mg (2.44 mmol) of palladium acetate, 2.97 g (9.76 mmol) of tri-tert-butylphosphine and 8.21 g (85.4 mmol) of sodium-tert-butoxide were added and heated under reflux for 1 hour.

After allowing to cool, filtration was performed to remove the catalyst. To the obtained filtrate, 100 ml of toluene and 100 ml of water were added, liquid separation extraction was performed, and the organic layer was separated. Further, the organic layer was washed with 100 ml of water. After repeating this washing operation three times, sodium sulfate was added to the organic layer to remove moisture. Next, o-xylene and toluene were distilled off from the resulting solution to obtain a crude product.

  The obtained crude product was purified using a silica gel column to obtain 26.5 g (yield: 91.2%) of the charge transport material of Example Compound CTM-30.

  Hereinafter, the charge transport materials used in the examples were synthesized in the same manner as in any one of Synthesis Examples 1 to 3, using the corresponding aryl halide and amine compound.

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

  The photosensitive layer of the electrophotographic photosensitive member of the present invention is a single-layer photosensitive member containing a charge generating material and a charge transporting material on a conductive support. Alternatively, it may be a function-separated type laminated photoreceptor in which a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material are laminated in this order on a conductive support. However, a function-separated type laminated photoreceptor is more preferable.

  As the support used in the electrophotographic photoreceptor of the present invention, any support may be used as long as it has conductivity. For example, a metal such as aluminum, copper, chromium, nickel, zinc, and stainless steel is molded into a drum or a sheet. Or what laminated | stacked metal foil, such as aluminum and copper, on the plastic film, what vapor-deposited aluminum, indium oxide, tin oxide etc. on the plastic film, etc. are mentioned.

  When the image input is laser light such as LBP, a conductive layer may be provided for the purpose of preventing interference fringes due to scattering or covering scratches on the support. This can be formed by dispersing conductive particles such as carbon black and metal particles in a binder resin.

  5-40 micrometers is preferable and, as for the film thickness of a conductive layer, 10-30 micrometers is more preferable.

  Further, an intermediate layer having an adhesive function may be provided on the support or the conductive layer.

  Examples of the material for the intermediate layer include polyamide, polyvinyl alcohol, polyethylene oxide, ethyl cellulose, casein, polyurethane, and polyether urethane. These are dissolved in an appropriate solvent and applied.

  The thickness of the intermediate layer is preferably 0.05 to 5 μm, more preferably 0.3 to 1 μm.

  Charge generation layer is a method such as homogenizer, ultrasonic dispersion, ball mill, vibration ball mill, sand mill, attritor, roll mill, liquid collision type high-speed disperser, etc. with charge generation material 0.3 to 4 times the amount of binder resin and solvent It is well dispersed and formed by applying and drying the dispersion.

  As the charge generating material used in the electrophotographic photosensitive member of the present invention, those generally known can be used. For example, azo pigments such as monoazo, disazo, and trisazo, and phthalocyanine pigments such as metal phthalocyanine and nonmetal phthalocyanine can be used.

  Indigo pigments such as indigo and thioindigo, and perylene pigments such as perylene anhydride and perylene imide can also be used as the charge generating substance. Polycyclic quinone pigments such as anthraquinone, pyrenequinone, and dibenzpyrenequinone, squarylium dyes, pyrylium salts and thiapyrylium salts, and triphenylmethane dyes can also be used as charge generating substances.

  Further, the charge generation material may be an inorganic material such as selenium, selenium-tellurium, amorphous silicon, a quinacridone pigment, or an azulenium salt pigment. Alternatively, cyanine dyes such as quinocyanine, anthanthrone pigments, pyranthrone pigments, xanthene dyes, quinoneimine dyes, styryl dyes, cadmium sulfide, and zinc oxide may be used. These charge generation materials may be used alone or in combination of two or more.

  The thickness of the charge generation layer is preferably 5 μm or less, more preferably 0.1 to 2 μm.

  In addition, various sensitizers, antioxidants, ultraviolet absorbers, plasticizers, and the like can be added to the charge generation layer as necessary.

  In the charge transport layer, at least a compound of the formula (1) or (2) is used as a charge transport material. The charge transporting material exemplified below can be used in combination as long as the effect of the present invention is not impaired, but the ratio of the charge transporting material represented by the above formula (1) or (2) is 50% or more. preferable. Further, it is more preferably 70% or more. Examples of charge transport materials that can be used in combination include triarylamine compounds having a molecular weight of 1000 or less, hydrazone compounds, styryl compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, triarylmethane compounds, and the like.

  The following can be used as the binder resin which is the resin binder of the charge transport layer. For example, acrylic resin, acrylonitrile resin, allyl resin, alkyd resin, epoxy resin, silicone resin, nylon, phenol resin, phenoxy resin, butyral resin, polyacrylamide resin, and polyacetal resin.

  The binder resin may be a polyamide-imide resin, a polyamide resin, a polyallyl ether resin, a polyarylate resin, a polyimide resin, or a polyurethane resin. Furthermore, polyester resins, polyethylene resins, polycarbonate resins, polystyrene resins, polysulfone resins, polyvinyl butyral resins, and polyphenylene oxide resins can also be used as binder resins.

  Further, the binder resin may be polybutadiene resin, polypropylene resin, methacrylic resin, urea resin, vinyl chloride resin, vinyl acetate resin, polyolefin resin, polycyclic olefin resin, or the like. In particular, polyarylate resin, polycarbonate resin, polycyclic olefin resin and the like are preferable as the binder resin. These may be used alone or in combination as a mixture or copolymer.

  The charge transport layer can be formed by applying a charge transport layer coating solution obtained by dissolving a charge transport material and a binder resin in a solvent, and drying it. The ratio between the charge transport material and the binder resin is preferably in the range of 2: 1 to 0.6: 1 (mass ratio).

  The thickness of the charge transport layer is preferably 5 to 40 μm, and more preferably 10 to 35 μm.

  When the charge transport layer is a surface layer of an electrophotographic photosensitive member, a lubricant or fine particles may be used as necessary. Examples of the lubricant or fine particles include resin fine particles such as polytetrafluoroethylene fine particles and polystyrene fine particles, and metal oxide fine particles such as silica fine particles, alumina fine particles, and tin oxide fine particles. Furthermore, fine particles obtained by subjecting the fine particles to surface treatment, solid lubricants such as zinc stearate, silicones substituted with alkyl groups, aliphatic oils having alkyl fluoride groups, varnishes, and the like may be used.

  Further, as a surface layer of the electrophotographic photoreceptor, a layer for protecting the photosensitive layer, that is, a protective layer may be separately provided on the photosensitive layer.

  The resin used for the protective layer is preferably a high molecular weight thermoplastic resin, a thermosetting resin, or a photocurable resin, and more preferably a high molecular weight polycarbonate resin, polyarylate resin, phenol resin, acrylic resin, or epoxy resin. preferable. Further, for the purpose of reducing the residual potential or improving the film strength, conductive particles or a lubricant may be contained.

  The film forming method of the protective layer can be cured by heat, light or electron beam, and may contain a polymerization initiator or an additive compound as necessary.

  In the step of forming each layer of the electrophotographic photoreceptor, examples of the solvent to be used include chlorobenzene, tetrahydrofuran, 1,4-dioxane, toluene, xylene and the like, and a single solvent or a plurality of solvents may be used.

  As the coating method, a conventionally known method such as a dip coating method, a spray coating method, a bar coating method, or the like can be used.

  Next, an electrophotographic apparatus having a process cartridge having the electrophotographic photosensitive member of the present invention will be described with reference to the drawings. This process cartridge integrally supports an electrophotographic photosensitive member, a charging unit, a developing unit, a transfer unit, and a cleaning unit that collects toner remaining on the electrophotographic photosensitive member after the transfer process. Further, it can be freely attached to and detached from the electrophotographic apparatus main body.

  FIG. 1 shows a schematic configuration of a contact charging type electrophotographic apparatus having a process cartridge having the electrophotographic photosensitive member of the present invention. This example is a transfer type copying machine or printer.

  In FIG. 1, an electrophotographic photoreceptor 1 is a drum type. The electrophotographic photosensitive member 1 is rotationally driven in a clockwise direction indicated by an arrow A with a predetermined peripheral speed (process speed).

  The charging roller 2 is a contact charging member as charging means. The charging roller 2 is applied with a DC voltage from the bias power source 2A and rotates in accordance with the rotation of the photoreceptor 1 that is press-fitted. As a result, the peripheral surface of the photoreceptor 1 is uniformly charged by the charging roller 2 with a predetermined polarity and potential by a so-called contact charging method.

  The surface of the photosensitive member 1 corresponding to the target image information is irradiated on the surface of the photosensitive member 1 by exposing the surface of the photosensitive member 1 to exposure 3 of the target image information by an unillustrated exposure unit (image forming exposure unit for a document image, laser beam scanner, etc.) An electrostatic latent image is formed.

  The formed electrostatic latent image is visualized as a transferable particle image (toner image) 5a by regular development or reversal development with the charged particles (toner) 5 of the developing device 4.

  Next, the toner image is transferred from the sheet feeding cassette 9 to the nip portion (transfer portion) between the photosensitive member 1 and the transfer roller 7 serving as a transfer unit pressed against the photosensitive member by the feeding roller 10 and the registration roller 11. The transferred particles 5b adhere to the paper 6 fed one by one at the timing. A bias voltage having a polarity opposite to the charge held in the toner 5 is applied to the transfer roller 7 from a bias power source 7A.

  The sheet 6 that has received the toner image transfer is separated from the surface of the photoreceptor 1 and is conveyed to a fixing means (not shown) to undergo a toner image fixing process.

  The surface of the photoreceptor 1 after the transfer of the toner image is cleaned by a cleaner (cleaning device) 8 to remove residual contaminants such as residual toner, and is repeatedly used for image formation.

  An example of a contact charging type full-color electrophotographic apparatus having a plurality of photosensitive members, a charging roller, and a developing device is shown in FIG. In this full-color electrophotographic apparatus, process cartridges similar to those in FIG. 1 containing toners of respective colors (black, cyan, magenta, yellow) are arranged in parallel in a vertical arrangement. This is a color electrophotographic apparatus called a tandem type in which transfer is performed sequentially by each transfer means, and finally fixing is performed.

  In FIG. 2, 20K, 20C, 20M, and 20Y are process cartridges for each color, and 21K, 21C, 21M, and 21Y are electrophotographic photosensitive members. 22K, 22C, 22M, and 22Y are charging rollers, 23 is a transfer roller, 24 is a paper conveying belt, 25 is a laser light source, 26K, 26C, 26M, and 26Y are toners of various colors, 27 is a fixing device, and 28 is a paper feed roller. .

  The electrophotographic photosensitive member of the present invention can be used not only in electrophotographic copying machines but also widely in electrophotographic application fields such as laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making.

  Examples of the photosensitive layer of the present invention are shown below, but the present invention is not limited thereto. In the examples, “part” means “part by mass”.

Example 1
An aluminum cylinder having a diameter of 30 mm and a length of 260.5 mm was used as a support.

Next, prepare 10 parts of SnO ₂ coated barium sulfate (conductive particles), 2 parts of titanium oxide (pigment for resistance adjustment), 6 parts of phenol resin (binder resin), 0.001 part of silicone oil (leveling agent) . Using these and a mixed solvent of 4 parts of methanol / 16 parts of methoxypropanol, a coating solution for a conductive layer was prepared.

  This conductive layer coating solution was dip-coated on a support and thermally cured at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 15 μm.

  Next, an intermediate layer coating solution was prepared by dissolving 3 parts of N-methoxymethylated nylon and 3 parts of copolymer nylon in a mixed solvent of 65 parts of methanol / 30 parts of n-butanol.

  This intermediate layer coating solution was dip-coated on the conductive layer and dried at 100 ° C. for 10 minutes to form an intermediate layer having a thickness of 0.7 μm.

  Next, strong peaks at 7.5 °, 9.9 °, 16.3 °, 18.6 °, 25.1 ° and 28.3 ° with a Bragg angle 2θ ± 0.2 ° of CuKα characteristic X-ray diffraction 10 parts of a crystalline form of hydroxygallium phthalocyanine (charge generating material) having This was added to a solution obtained by dissolving 5 parts of polyvinyl butyral resin (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) in 250 parts of cyclohexanone. Dispersion was performed in a 23 ± 3 ° C. atmosphere for 1 hour with a sand mill using glass beads having a diameter of 1 mm, and after dispersion, 250 parts of ethyl acetate was added to prepare a charge generation layer coating solution.

  The charge generation layer coating solution was dip coated on the intermediate layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.20 μm.

  Next, 9 parts of a charge transport material indicated by CTM-13 and 10 parts of polycarbonate resin (trade name: Iupilon Z-400, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) are prepared as a resin binder. These were dissolved in a mixed solvent of 80 parts of monochlorobenzene and 10 parts of dimethoxymethane to prepare a charge transport layer coating solution. This was applied onto the charge generation layer by dipping and dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 16 μm (near the center).

  Thus, the electrophotographic photosensitive member used in each example was produced.

  Next, the evaluation method will be described. The produced electrophotographic photosensitive member was evaluated according to the following.

  First, ghost image evaluation was performed as image evaluation. For the evaluation, a laser beam printer LBP-2510 (charge (primary charge): contact charging method, process speed: 94.2 mm / s) manufactured by Canon Inc. was used as an evaluation apparatus. The modification made it possible to adjust the charging potential (dark portion potential) and the image exposure amount of the electrophotographic photosensitive member, and to prevent the static eliminator from operating.

  The evaluation was performed in an environment at room temperature of 15 ° C. and humidity of 10%.

  Further, the charging potential (dark portion potential) and the image exposure amount were adjusted so that the dark portion potential was set to -500v and the bright portion potential was set to -100v.

  The electrophotographic photosensitive member produced in the above example was mounted on the cyan process cartridge, and this was mounted on the cyan process cartridge station of the printer, and an evaluation image was output.

  Image output for ghost image evaluation was performed as follows.

  After continuously outputting 1000 A4 size 5% printed image patterns, the following evaluation images were output.

  As an evaluation image, as shown in FIG. 3, a halftone image printed with a 1-dot Keima pattern after a black square image was output at the head of the image was used. The evaluation of the ghost image is performed by subtracting the image density that is not the ghost part from the image density of the ghost part of the image printed with the 1-dot Keima pattern using a spectral densitometer X-Rite 504/508 (manufactured by X-Rite). Was the ghost concentration. Ten points of this were measured with one ghost image, and the average value of these 10 points was obtained.

  In this evaluation, the difference in the ghost image density is 0.05 or more, and there is a clear difference, and it is the NG level. If it was less than 0.05, it was a level with no apparent difference.

  Next, photo memory evaluation was performed.

  The photo memory evaluation was performed by irradiating a part of the electrophotographic photosensitive member with 3000 lux white fluorescent light for 20 minutes, leaving it for 5 minutes, measuring the bright part potential, and how much the bright part potential dropped before the light was applied. Was measured as a photo memory value.

  Furthermore, precipitation with time was evaluated.

The above-described LBP2510 urethane rubber cleaning blade was pressed against the electrophotographic photosensitive member, stored at 75 ° C., and subjected to an acceleration test for precipitation. Evaluation was made after 14 days by observing the surface of the photoreceptor with a microscope to determine the presence or absence of precipitation. When there was no precipitation, the test was continued until 30 days later.
The results are shown in Table 2.

(Example 2 to Example 30)
A photoconductor was prepared in the same manner as in Example 1 except that the charge transport material in the charge transport layer was changed to that shown in Table 1, and the same evaluation was performed. The results are shown in Table 2.

(Example 31 to Example 60)
The resin binder of the charge transport layer of Examples 1 to 30 was changed to a polycyclic olefin resin binder (trade name: TOPAS-5013, manufactured by Ticona, Tg: 130 ° C.) which is a copolymer having the following repeating structural units. Except this, a photoconductor was prepared in the same manner as in Examples 1 to 30, and the same evaluation was performed. The results are shown in Table 2.

(Comparative Examples 1-8)
In Examples 7, 10, 12, 15, 17, 20, 23, 27, Examples 7, 10, except that the charge transport material of the charge transport layer was changed to that of Comparative CTM-1 to 8 in Table 3 below. Photoconductors were prepared in the same manner as 12, 15, 17, 20, 23, and 27, and the same evaluation was performed. The results are shown in Table 4.

(Comparative Examples 9 and 10)
A photoconductor was prepared and evaluated in the same manner as in Example 12 except that the charge transport material of Example 12 was replaced with Comparative CTM-9 and Comparative CTM-10 in Table 5 below, respectively. The results are shown in Table 6.

(Comparative Examples 11-18)
Examples 37, 40, 42, 45, 47, 50, 53, 57 Examples 37, 40, 42, 45, except that the charge transport materials were changed to Comparative CTM-1 to 8 in Table 3 above. Photoconductors were prepared in the same manner as 47, 50, 53 and 57, but in all cases, the charge transport layer became a cloudy film. When the electrophotographic characteristics were confirmed, the sensitivity was low, and the bright part potential could not be set to −100 v, so that the ghost image could not be evaluated. Other evaluation results are shown in Table 7.

  When Examples and Comparative Examples are compared, the ghosts in Comparative Examples 1 to 8 using a charge transport material having no alkyl group having 6 to 10 carbon atoms with respect to the photoreceptor in the present invention are ghosted. And the photo memory is not good. In the precipitation test, the charge transport material was deposited after 14 days. In the photoreceptors of Comparative Examples 11 to 18, the charge transport layer became a cloudy film, and sufficient electrophotographic characteristics were not obtained.

  Even in the photoreceptors using Comparative CTM-9 and Comparative CTM-10 which have an alkyl group having 6 to 10 carbon atoms but have different structures of charge transport materials, ghosts and photo memories are not good, and precipitation occurs. In the test, the result was precipitated after 30 days.

  That is, only when the charge transport material of the present invention is used as a photoconductor, it is considered that the ghost suppressing effect and the photomemory reducing effect are manifested. Further, it can be said that the electrophotographic photosensitive member of the present invention is a stable photosensitive member in which precipitation does not occur even during long-term storage.

  Therefore, according to the present invention, it is possible to provide an electrophotographic photosensitive member that has an image quality that does not cause ghosting, that does not cause photo memory, and that is stable for long-term storage.

FIG. 2 is a diagram illustrating an example of a contact charging type process cartridge and an electrophotographic apparatus. FIG. 2 is a diagram illustrating an example of a full-color contact charging type electrophotographic apparatus in which the process cartridges illustrated in FIG. 1 are arranged in a tie-down manner in vertical order from yellow, magenta, cyan, and black in order. It is a figure which shows the image for evaluation used in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Charging roller 2A Bias power supply 3 Exposure 4 Developer 5 Charged particle (toner)
5a Transferable particle image (toner image)
5b Particles to be transferred 6 Paper 7 Transfer roller 7A Bias power supply 8 Cleaner (cleaning device)
DESCRIPTION OF SYMBOLS 9 Paper feed cassette 10 Paper feed roller 11 Registration roller 20K, 20C, 20M, 20Y Each color process cartridge 21K, 21C, 21M, 21Y Electrophotographic photosensitive member 22K, 22C, 22M, 22Y Charging roller 23 Transfer roller 24 Paper conveyance belt 25 Laser Light source 26K, 26C, 26M, 26Y Each color toner 27 Fixing device 28 Paper feed roller

Claims (6)

On a conductive support an electrophotographic photosensitive member having a photosensitive layer, the photosensitive layer contains a resin binder, and that electric charge transport material having an alkyl group having 6 to 10 carbon atoms, a,
The electrophotographic photoreceptor , wherein the charge transport material having an alkyl group having 6 to 10 carbon atoms is at least one of compounds represented by the following general formula (1) or (2) .

(In the above formula _{(1), R} 101 ~R ₁₂₈ is hydrogen atom, substituted showing also alkyl groups. _Further, at least two of R 101 _{to R 120,} the number 6 to 10 carbon (However, it does not have two or more alkyl groups having 6 to 10 carbon atoms on the same benzene ring. X has a structure selected from the following group.)


(In the above formula (2), R _{201 to} R ₂₂₀ represent a hydrogen atom and an alkyl group which may have a substituent, and at least two are alkyl groups having 6 to 10 carbon atoms, provided that the same benzene (It does not have two or more alkyl groups having 6 to 10 carbon atoms on the ring at the same time. Y has a structure selected from the following group.)

(The above R _{1 to} R ₃ represent _a methyl group or an ethyl group.) The electrophotographic photoreceptor according to claim 1 , wherein the compound represented by the general formula (1) has a linear alkyl group having 6 to 8 carbon atoms. The resin binder may electrophotographic photosensitive member according to claim 1 or 2, characterized in that a polyolefin resin. The photosensitive layer, the electrophotographic photosensitive member according to any one of claims 1 to 3, characterized in that a layered photoreceptor having a charge generating layer and a charge transport layer. An electrophotographic photosensitive member according to any one of claims 1 to 4, charging means for charging the electrophotographic photoreceptor, developing means for developing an electrophotographic photoreceptor formed of an electrostatic latent image with toner, Together with at least one means selected from the group consisting of a transfer means for transferring a toner image on the electrophotographic photosensitive member onto a transfer material and a cleaning means for recovering toner remaining on the electrophotographic photosensitive member after the transfer step. A process cartridge that is integrally supported and detachable from the electrophotographic apparatus body. The electrophotographic photosensitive member according to any one of claims 1 to 4, charging means for charging the electrophotographic photoreceptor, an exposure means of the electrophotographic photosensitive member, an electrophotographic photosensitive member which is formed of an electrostatic latent image An electrophotographic apparatus comprising: developing means for developing the toner with toner; and transfer means for transferring a toner image on the electrophotographic photosensitive member onto a transfer material.