JP4143497B2 - Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member, an electrophotographic apparatus including the electrophotographic photosensitive member, and a process cartridge.

  Conventionally, as an electrophotographic photoreceptor using an organic photoconductive substance, a photoconductive polymer typified by poly-N-vinylcarbazole and 2,5-bis (p-diethylaminophenyl) -1,3,4- Known are those using a low molecular organic photoconductive material such as oxadiazole, and combinations of such organic photoconductive materials with various dyes and pigments.

  Recently, the development of a functionally-separated type photoreceptor in which a charge generation layer containing an organic photoconductive dye or pigment and a charge transport layer containing a photoconductive polymer or a low-molecular organic photoconductive material are stacked has been developed. Significant improvements have been made in sensitivity and durability, which have been regarded as disadvantages of organic electrophotographic photoreceptors, and this has become the mainstream of organic electrophotographic photoreceptors.

  On the other hand, as a matter of course, the electrophotographic photoreceptor is required to have sensitivity, electrical characteristics, and optical characteristics according to the applied electrophotographic process. In particular, for photoreceptors that are used repeatedly, the surface of the photoreceptor is subjected to electrical and mechanical external forces such as electrification, image exposure, toner development, transfer to paper, and cleaning treatment, so its durability against them Is required. Specifically, durability against surface abrasion and scratches due to rubbing, surface deterioration due to charging, such as transfer efficiency and slipperiness, and durability against electrical property deterioration such as sensitivity reduction and potential reduction are also required. Is done.

  As an electrophotographic photoreceptor developed from such a demand, for example, an electrophotographic photoreceptor having a layer formed by polymerizing a hole transporting compound having two or more chain polymerizable functional groups in the same molecule on the surface. Is known (see, for example, Patent Document 1). It is known that this electrophotographic photoreceptor can substantially achieve both mechanical strength and charge transport capability.

However, even in the electrophotographic photosensitive member, even if the initial characteristics are good, the cleaning characteristics and image characteristics during long-term durability are not always sufficient, and the cleaning blade is turned up, or image flow occurs under high temperature and high humidity. Sometimes happened.
JP 2000-66424 A

  An object of the present invention is to solve the above problems and to provide an excellent electrophotographic photosensitive member. That is, an object of the present invention is to provide an electron having a layer formed by polymerizing a hole transporting compound having two or more chain polymerizable functional groups in the same molecule and having excellent mechanical strength and charge transporting ability. It is an object of the present invention to provide a photographic photosensitive member, and a process cartridge and an electrophotographic apparatus having the photographic photosensitive member.

As a result of intensive studies, the inventors of the present invention form a surface of the electrophotographic photosensitive member in an electrophotographic photosensitive member having a conductive support and a photosensitive layer provided on the conductive support. The surface layer is formed by polymerizing a hole transporting compound monomer having two or more chain polymerizable functional groups, and the content of the hole transporting compound monomer remaining in the surface layer is determined based on the content of the surface layer. It has been found that an electrophotographic photosensitive member characterized by being 0.5% by mass or less based on the total weight can solve the above-mentioned problems.

  The present invention also provides the electrophotographic photosensitive member, and a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

  The electrophotographic photosensitive member of the present invention has excellent electrophotographic characteristics and durable image characteristics, and is excellent in mechanical strength, and therefore has excellent cleaning characteristics. Therefore, according to the present invention, an image with high image quality can be stably formed over a long period of time on an organic electrophotographic photosensitive member with high productivity.

  The effect of the electrophotographic photosensitive member is naturally exhibited also in a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

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

  The electrophotographic photoreceptor of the present invention has a conductive support and a photosensitive layer provided on the conductive support. In addition to the photosensitive layer, the electrophotographic photosensitive member of the present invention may have other layers as long as the function of the photosensitive layer is not impaired.

  The conductive support is not particularly limited as long as it has conductivity and can support the photosensitive layer. As such a conductive support, for example, a metal or alloy such as aluminum, copper, chromium, nickel, zinc and stainless steel formed into a drum or a sheet, or a metal foil such as aluminum or copper is laminated on a plastic film. And metal, plastic film, paper, and the like in which a conductive material is applied alone or with a binder resin to provide a conductive layer.

  The photosensitive layer is a layer having a function of generating charges by exposure and a function of transporting the generated charges, and is not particularly limited as long as it forms an electrostatic latent image by exposure. As such a photosensitive layer, for example, a so-called single layer type photosensitive layer containing a charge generation material and a charge transport material in the same layer, a charge generation layer containing a charge generation material, and a charge generation layer on the charge generation layer A so-called laminated photosensitive layer that is functionally separated into a charge transporting layer that is provided and has a charge transporting property is exemplified. In the present invention, the photosensitive layer may be any photosensitive layer, but is preferably a laminated photosensitive layer.

  The surface of the electrophotographic photoreceptor is formed by a layer formed by polymerizing a hole transporting compound monomer having two or more chain polymerizable functional groups. The surface layer is not particularly limited as long as it is a layer formed by polymerizing the hole transporting compound monomer, and may be a photosensitive layer itself or a charge transport layer in the multilayer photosensitive layer. It may be another layer such as a protective layer provided on the photosensitive layer to protect the photosensitive layer from damage due to mechanical force. In addition to the photosensitive layer and the protective layer, the electrophotographic photosensitive member may have other appropriate layers provided between the conductive support and the photosensitive layer.

The hole transporting compound monomer has two or more chain polymerizable functional groups in the same molecule. The chain polymerizable functional group that the hole transporting compound monomer has in the same molecule may be one type of functional group or two or more types of functional groups. In the present invention, “a hole transporting compound monomer having two or more chain polymerizable functional groups in the same molecule” means two or more in the same molecule described in detail in JP-A No. 2000-66424. 2 shows a hole transporting compound having a chain polymerizable functional group. As the hole transporting compound monomer, a monomer having a hole transporting functional group and the chain polymerizable functional group can be used. The hole transporting compound monomer may have other various functional groups as long as the hole transporting property and the chain polymerization property in these functional groups are not hindered.

  The functional group having hole transportability may be any as long as it exhibits hole transportability. As such a functional group having a hole transporting property, for example, a hole transporting group described in JP-A No. 2000-66424 can be used. Examples of the functional group having a hole transporting property used in the present invention include an oxazole derivative and an oxadiazole derivative when a hydrogen addition compound in which another functional group bonded to the functional group is replaced with a hydrogen atom is used. Imidazole derivatives, diarylamine derivatives such as diphenylamine, triarylamine derivatives such as triphenylamine, 9- (p-diethylaminostyryl) anthracene, 1,1-bis- (4-dibenzylaminophenyl) propane, styrylanthracene, Compounds such as styrylpyrazolines, phenylhydrazones, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, thiophene derivatives and N-phenylcarbazole derivatives, or these The number and the like functional group which is a complex formed by coalescence.

  The chain polymerizable functional group means a functional group capable of chain polymerization. The chain polymerization refers to the former form of polymerization reaction when the polymer formation reaction is largely divided into chain polymerization and sequential polymerization. For details, refer to “Basic Chemistry Resin Chemistry” (new edition) ) "July 25, 1995 (1 edition, 8 prints) As described in FIG. 24, the form mainly refers to unsaturated polymerization, ring-opening polymerization, isomerization polymerization, etc. in which the reaction proceeds via an intermediate such as a radical or ion. The chain polymerizable functional group is not particularly limited as long as it is a functional group capable of the above-described reaction form. For example, the unsaturated polymerizable functional group and the ring-opening polymerizable functional described in JP-A-2000-66424. And chain polymerizable functional groups such as a group.

  In the present invention, the hole-transporting compound monomer having two or more chain polymerizable functional groups in the same molecule is subjected to either or both of polymerization and crosslinking, and a composition containing the monomer is obtained. The surface layer can be formed by curing. This surface layer is obtained by polymerizing / crosslinking only the hole transporting compound monomer or using a mixture of a compound having another polymerizable group and the hole transporting compound monomer, Both can be formed by polymerization and crosslinking. The hole transporting compound monomer forming the surface layer may be one type of functional group or two or more types of functional groups.

  As used herein, the compound having another chain polymerizable group includes any monomer or oligomer / polymer having a chain polymerizable group. Further, the surface layer may be formed from a monomer or an oligomer / polymer having a polymerizable group other than the hole transporting compound monomer and the chain polymerizable functional group. Further, in some cases, it is possible to contain a hole transporting compound that is not chemically incorporated into the three-dimensional crosslinked structure, that is, a hole transporting compound that does not have a chain polymerizable functional group.

  In the present invention, the content of the hole transporting compound monomer remaining in the surface layer is 1% by mass or less with respect to the total weight of the surface layer in order to improve cleaning characteristics and image characteristics. In order to further improve the above-described characteristics, the content is more preferably 0.5% by mass or less.

In the present invention, the hole transporting compound monomer remaining in the surface layer means that all the chain polymerizable functional groups in the hole transporting compound monomer are unreacted. That is, when even one chain polymerizable functional group is involved in the polymerization, it does not correspond to the residual monomer. The content of the residual monomer can be reduced by, for example, heating the electrophotographic photoreceptor to about 50 to 150 ° C. in an inert gas atmosphere after forming the surface layer.

  Various other additives can be added to the surface layer. Examples of the additive include deterioration inhibitors such as antioxidants and ultraviolet absorbers, and lubricants such as fluorine atom-containing resin fine particles.

  Next, a method for producing an electrophotographic photoreceptor according to the present invention will be specifically described.

  In the present invention, an undercoat layer having a barrier function and an adhesive function can be provided on the conductive support. The undercoat layer is formed for improving the adhesion of the photosensitive layer, improving the coating property, improving the charge injection property from the conductive support, and protecting the photosensitive layer from electrical breakdown.

  Materials for the undercoat layer include polyvinyl alcohol, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, ethylene-acrylic acid copolymer, casein, polyamide, N-methoxymethylated 6 nylon, copolymer nylon, glue, gelatin, etc. It has been known. These are dissolved in a solvent suitable for each and coated on a support. The film thickness at that time is preferably 0.1 to 2 μm.

  Furthermore, in the present invention, defects of the conductive support or interference fringes generated when coherent light is used are formed between the conductive support and the photosensitive layer, or between the conductive support and the undercoat layer. For the purpose of prevention, a resin layer in which conductive particles are dispersed can be provided as a conductive layer. The film thickness is preferably 5 to 30 μm.

  When the electrophotographic photoreceptor of the present invention is a function separation type photoreceptor, a charge generation layer and a charge transport layer are laminated. Examples of the charge generation material used in the charge generation layer include selenium-tellurium, pyrylium, thiapyrylium dyes, various central metals and crystal systems, specifically, crystal types such as α, β, γ, ε, and X types. Phthalocyanine compounds, anthanthrone pigments, dibenzpyrenequinone pigments, pyranthrone pigments, trisazo pigments, disazo pigments, monoazo pigments, indigo pigments, quinacridone pigments, asymmetric quinocyanine pigments, quinocyanines and amorphous materials described in JP-A No. 54-143645 Silicon etc. are mentioned.

  In the case of a function-separated type photoreceptor, the charge generation layer comprises the charge generation material together with a binder resin and a solvent in an amount of 0.3 to 4 times, a homogenizer, an ultrasonic dispersion, a ball mill, a vibration ball mill, a sand mill, an attritor, and the like. It is well dispersed by a method such as a roll mill, and is formed by applying the dispersion on the undercoat layer and drying the coating film, or as a single composition film such as a vapor deposition film of the charge generation material. Is done. The film thickness is preferably 5 μm or less, and particularly preferably in the range of 0.1 to 2 μm.

  Examples of the binder resin include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic acid ester, methacrylic acid ester, vinylidene fluoride, trifluoroethylene, polyvinyl alcohol, polyvinyl acetal, Examples include polycarbonate, polyester, polysulfone, polyphenylene oxide, polyurethane, cellulose resin, phenol resin, melamine resin, silicon resin, and epoxy resin. Moreover, a well-known organic solvent or its mixed solvent is used suitably for the said solvent.

The surface layer is formed as a charge transport layer on the above-described charge generation layer, or formed as a protective layer on the charge generation layer formed of a charge transport material and a binder resin on the charge generation layer. Is done. In any case, after the surface layer is coated on the charge generation layer or the charge transport layer with the solution containing the hole transport compound monomer, the hole transport compound monomer in the coating film is polymerized / cured. It can be formed by reacting. As a method for applying these solutions, for example, a dip coating method, a spray coating method, a curtain coating method, a spin coating method and the like are known. From the viewpoint of efficiency / productivity, the dip coating method is preferable. As the method for forming the surface layer, vapor deposition, plasma, or other known film forming methods can be selected as appropriate.

  In the present invention, the hole transporting compound monomer having two or more functional groups in the same molecule can be polymerized and cured by heat, light such as visible light, ultraviolet light, or radiation. Therefore, the surface layer in the present invention contains the hole transporting compound monomer and, if necessary, a polymerization initiator in the surface layer coating liquid, and the coating film formed using the coating liquid, The hole-transporting compound monomer can be polymerized by irradiation with heat, light or radiation. In the present invention, it is preferable to polymerize and cure by radiation. That is, the surface layer is preferably a layer formed by irradiating the hole transporting compound monomer with radiation to polymerize the hole transporting compound monomer.

  The greatest advantage of polymerization by radiation is that it does not require a polymerization initiator, thereby ensuring good electrophotographic characteristics. This is presumably because a very high purity three-dimensional photosensitive layer matrix is produced. In addition, because it is a short and efficient polymerization reaction, it is highly productive, and because of its good radiation permeability, it inhibits curing when a thick film or additives such as additives are present in the film. The influence of the is very small. The surface layer is preferably a layer formed by irradiating the hole transporting compound monomer with radiation to polymerize the hole transporting compound monomer in order to obtain the various advantages described above. However, depending on the type of the central skeleton of the hole transporting compound monomer, the polymerization reaction may not proceed easily, and in this case, it is possible to add a polymerization initiator within a range that does not affect the polymerization reaction.

  The radiation is an electron beam or γ-ray. It is preferable that the radiation is an electron beam in order to polymerize the hole transporting compound monomer and obtain the various advantages described above. In the case of electron beam irradiation, any type of accelerator such as a scanning type, an electro curtain type, a broad beam type, a pulse type, and a laminar type can be used. When irradiating with an electron beam, in the electrophotographic photosensitive member of the present invention, irradiation conditions are important for developing electrical characteristics and durability. In the present invention, the acceleration voltage is preferably 250 kV or less, and optimally 150 kV or less. The irradiation dose is preferably in the range of 0.1 Mrad to 100 Mrad, more preferably in the range of 0.5 Mrad to 20 Mrad. When the acceleration voltage exceeds the above, damage to the photoreceptor due to electron beam irradiation tends to increase, and the photoreceptor characteristics tend to deteriorate due to electron beam irradiation. Further, when the irradiation dose is less than the above range, the curing tends to be insufficient, and when the irradiation dose is large, the photoreceptor characteristics tend to be deteriorated due to deterioration of the photoreceptor.

  Moreover, in order to perform sufficient hardening, it is desirable to add heat at the time of the polymerization reaction by an electron beam. The timing of applying heat may be any before, during, or after electron beam irradiation as long as the photoconductor, which is an object to be irradiated, is at a constant temperature while radicals are present. The heating temperature is preferably from room temperature to 250 ° C, particularly preferably from 50 ° C to 150 ° C. When the temperature is higher than the above range, the material of the electrophotographic photoreceptor tends to deteriorate and the electrophotographic characteristics tend to deteriorate. The time for heating is approximately several seconds to several tens of minutes depending on the temperature. The atmosphere for irradiation and heating may be any of air, an inert gas such as nitrogen and helium, or a vacuum, but it can suppress the deactivation of radicals due to oxygen. A vacuum is preferred.

  When the surface layer is a charge transport layer, the thickness of the charge transport layer is preferably 1 to 50 μm, and particularly preferably 3 to 30 μm.

  When the surface layer is the protective layer, the charge transport layer corresponding to the lower layer is a polymer having a suitable charge transport material, for example, poly-N-vinylcarbazole, polystyrylanthracene, or a heterocycle or condensed polycyclic aromatic. Compounds, heterocyclic compounds such as pyrazoline, imidazole, oxazole, triazole, carbazole, triarylalkane derivatives such as triphenylmethane, triarylamine derivatives such as triphenylamine, phenylenediamine derivatives, N-phenylcarbazole derivatives, stilbene derivatives A solution in which a low molecular weight compound such as a hydrazone derivative is dispersed / dissolved in a solvent together with an appropriate binder resin (which can be selected from the aforementioned resin for charge generation layer) is applied and dried by the above-mentioned known method. Can be formed.

  In this case, the ratio of the charge transport material to the binder resin is preferably selected in the range of 30 to 100, preferably 30 to 100, when the total weight of both is 100. If the amount of the charge transporting material is less than that, the charge transporting ability is lowered, and problems such as a decrease in sensitivity and an increase in residual potential may occur. In this case, the thickness of the charge transport layer is preferably adjusted in the range of 1 to 50 μm, more preferably 3 to 30 μm.

  When the surface layer is the protective layer, the thickness of the protective layer is preferably 0.5 to 10 μm, particularly preferably 1 to 7 μm.

  As a method for forming a single layer type photosensitive layer, a solution containing the hole transporting compound monomer and the charge generating material is applied on a conductive support which may be provided with an appropriate undercoat layer, and then polymerized, Applying a solution containing the hole transporting compound monomer onto a single-layer type photosensitive layer composed of a charge generating material and a charge transporting material provided on a conductive support, when cured. Thereafter, any of the cases of polymerization and curing to form a protective layer is possible.

  As described above, the initial characteristics and abrasion resistance are sufficient even in an electrophotographic photoreceptor formed by polymerizing and curing a hole transporting compound having a surface layer having two or more functional groups in the same molecule. However, the image characteristics and the cleaning characteristics are not always sufficient as the durability characteristics, and the image flow under high temperature and high humidity and the blade turning may occur.

  As a result of intensive studies, the present inventors have found that there is a relationship between the content of the residual monomer with respect to the total weight of the surface layer after polymerization / curing, and the cleaning characteristics and image characteristics as a photoreceptor, leading to the present invention. . That is, the surface layer is formed by polymerizing and curing a hole transporting compound monomer having two or more chain-polymerizable functional groups in the same molecule, and the residual monomer contained in the surface layer after polymerization and curing By using an electrophotographic photosensitive member whose amount is 1% by mass or less with respect to the total weight of the surface layer, the cleaning characteristics and the image characteristics are dramatically improved. In order to further improve the characteristics, a surface layer having a residual monomer content of 0.5% by mass or less is more preferable.

  The reason why the cleaning characteristics and the image characteristics have been drastically improved is presumed that the residual monomer contained in the surface layer moves to the outermost surface due to a temperature rise or the like during durability. It is considered that the residual monomer that has migrated to the surface increases the friction with the cleaning member or causes image flow under high temperature and high humidity.

If at least one of the chain-polymerizable functional groups of the hole-transporting compound monomer is involved in the polymerization, the hole-transporting compound monomer is chemically bonded to the three-dimensional cross-linked structure. In this case, it does not migrate to the surface. The reason why the initial characteristics and the wear resistance were good even when the monomer ratio was larger than 1% by mass was that the monomers retained the hole transport function, so even if they migrated to the surface, the potential characteristics. It is considered that there was no effect on the wear resistance, since the remaining monomers other than 1% by mass or less were involved in the polymerization reaction.

  The residual monomer in the surface layer can be measured by the following method.

The surface layer of the electrophotographic photoreceptor was peeled and pulverized, and 1 g of the obtained powder was reflux extracted (100 ° C., 4 hours) with 100 ml of a solvent such as ethanol in which the hole transporting compound monomer is soluble, The extract solution is concentrated with an evaporator to obtain an extract. 1 part by mass of this extract is dissolved in 400 parts by mass of an appropriate solvent such as THF, and quantified by HPLC (high-speed liquid phase chromatograph) by the absolute calibration curve method under the following conditions.
<Conditions>
Measuring device: SERIES1100 (manufactured by HP)
Column: ODSpak F-411
Flow rate: 1.5ml / min
Moving bed (methanol / water): 90/10 → 100/0 (%)
Sample volume: 20 μl
FIG. 1 shows a schematic configuration of an electrophotographic apparatus having a process cartridge having the electrophotographic photosensitive member of the present invention. In the figure, an electrophotographic photosensitive member 1 that is driven to rotate at a predetermined peripheral speed in the direction of an arrow about an axis 2, a primary charging means 3 that charges the electrophotographic photosensitive member 1, and a charged electrophotographic photosensitive member 1. Development means 5 for developing the electrostatic latent image with toner, and cleaning means 9 for removing the toner remaining on the electrophotographic photoreceptor 1 after the transfer of the toner image formed on the electrophotographic photoreceptor 1. The electrophotographic photosensitive member 1, the primary charging unit 3, the developing unit 5, and the cleaning unit 9 are integrally supported. The process cartridge 11 is detachably attached to the apparatus main body using guide means such as a rail 12 of the apparatus main body.

  In addition to the rail 12, the electrophotographic apparatus shown in FIG. 1 has transfer means 6 for transferring a toner image on the electrophotographic photosensitive member 1 to a transfer material 7, and an unfixed toner image transferred to the transfer material 7. The image fixing means 8 for fixing, the exposure means (not shown) for irradiating the electrophotographic photosensitive member 1 with light corresponding to the electrostatic latent image to be formed on the charged electrophotographic photosensitive member 1, and the cleaning means 9 And a pre-exposure means (not shown) for irradiating the electrophotographic photosensitive member 1 with light for erasing the electrostatic history of the electrophotographic photosensitive member 1 after removal of the electrophotographic photosensitive member 1

  The electrophotographic photoreceptor 1 is driven to rotate at a predetermined peripheral speed in the direction of the arrow about the shaft 2. 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 unit 3, and then from an image exposure unit (not shown) such as slit exposure or laser beam scanning exposure. The image exposure light 4 is received. In this way, electrostatic latent images are sequentially formed on the peripheral surface of the photoreceptor 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 is read as a signal by a sensor, converted into a signal, and laser beam scanning performed according to this signal. Light emitted by driving the LED array, driving the liquid crystal shutter array, or the like.

  The formed electrostatic latent image is then developed with toner by the developing means 5, and the formed toner image is taken out from a paper feeding unit (not shown) and fed in synchronization with the rotation of the electrophotographic photosensitive member 1. The transfer means 6 sequentially transfers the transfer material 7 onto the transfer material 7. The transfer material 7 that has received the image transfer is separated from the surface of the electrophotographic photosensitive member 1, introduced into the image fixing means 8, and subjected to image fixing to be printed out as a copy (copy).

  After the image transfer, the surface of the photoreceptor 1 is cleaned by removing the transfer residual toner by the cleaning unit 9, and is further subjected to a charge removal process by the pre-exposure light 10 from the pre-exposure unit (not shown), and then 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 need not be performed.

  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.

  Hereinafter, the present invention will be described with reference to examples.

<Example 1>
50 parts of conductive titanium oxide powder coated with tin oxide containing 10% antimony oxide (mass parts, hereinafter the same), phenol resin 25 parts, methyl cellosolve 20 parts, methanol 5 parts and silicone oil (polydimethylsiloxane poly) 0.002 part of an oxyalkylene copolymer (average molecular weight 3000) was dispersed for 2 hours in a sand mill using glass beads having a diameter of 1 mm to prepare a coating material for a conductive layer. This paint was applied on an aluminum cylinder having a diameter of 30 mm by a dip coating method and dried at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 20 μm.

  Next, 5 parts of N-methoxymethylated nylon was dissolved in 95 parts of methanol to prepare an undercoat layer coating material. This paint was applied onto the conductive layer by a dip coating method and dried at 100 ° C. for 20 minutes to form a 0.6 μm undercoat layer.

  Next, 3 parts of oxytitanium phthalocyanine having strong peaks at 9.0 degrees, 14.2, 23.9 degrees, and 27.1 degrees with black angles 2θ ± 0.2 degrees in X-ray diffraction of CuKα, polyvinyl Disperse 3 parts of butyral (trade name ESREC BM2, manufactured by Sekisui Chemical Co., Ltd.) and 35 parts of cyclohexanone in a sand mill using glass beads with a diameter of 1 mm for 2 hours, and then add 60 parts of ethyl acetate to charge. A coating for the generation layer was prepared. This paint was applied onto the undercoat layer by a dip coating method and dried at 50 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

  Next, 60 parts of a hole transporting compound monomer represented by the following structural formula (1) was dissolved in a mixed solvent of 30 parts of monochlorobenzene and 30 parts of dichloromethane to prepare a charge transport layer coating solution. This paint was applied onto the charge generation layer by a dip coating method, and this coating film was irradiated with an electron beam under an atmosphere having an oxygen concentration of 10 ppm and an acceleration voltage of 150 kV and an irradiation dose of 10 Mrad. Subsequently, a heat treatment was performed for 10 minutes under the same atmosphere at a temperature of 80 ° C. to form a charge transport layer having a thickness of 15 μm, thereby obtaining an electrophotographic photoreceptor.

  According to the above procedure, an electrophotographic photoreceptor for measuring the amount of residual monomer and an electrophotographic photoreceptor for actual machine testing were produced. The charge transport layer of the obtained electrophotographic photoreceptor for measurement was peeled off, and the amount of residual monomer contained in the charge transport layer was measured and found to be 0.47% by mass with respect to the total weight of the charge transport layer.

An electrophotographic photosensitive member for testing an actual machine is mounted on an LBP-SX manufactured by Canon Inc., and initial electrophotographic characteristics, image characteristics, cleaning characteristics under normal temperature and humidity, and images under high temperature and high humidity Characteristics and cleaning characteristics were evaluated.

  Regarding the electrophotographic characteristics, the light attenuation sensitivity and the residual potential Vsl were measured with the LBP-SX developing device modified for variable light quantity removed and the potential measurement probe installed at the same position. The light attenuation sensitivity is the amount of light necessary for light attenuation of the surface potential of the electrophotographic photosensitive member from −700 V that is a dark portion potential to −200 V that is a light portion potential. The residual potential is the surface potential of the electrophotographic photosensitive member when a light amount five times the light attenuation sensitivity is irradiated.

  The image characteristics and the cleaning characteristics were evaluated based on the occurrence of image flow and the occurrence of turning over of the cleaning blade after 10,000 sheets were used for continuous continuous paper use.

The image characteristics and cleaning characteristics under high temperature and high humidity are as follows: The evaluation machine and paper for passing paper are allowed to stand under high temperature and high humidity of 35 ° C and 85% for 24 hours, and then the continuous use of the paper continuously in the same environment. Was evaluated by the presence or absence of image flow and turning up of the cleaning blade. The results are shown in Table 1.
<Examples 2 to 4>
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the heating conditions after the electron beam irradiation in Example 1 were changed to 100 ° C., 130 ° C., and 160 ° C., and the amount of residual monomer was determined and evaluated. The results are shown in Table 1.
<Comparative Example 1>
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that heating after electron beam irradiation was not performed, and the amount of residual monomer was determined and evaluated. The results are shown in Table 1.
<Comparative Examples 2 and 3>
An electrophotographic photosensitive member was prepared in the same manner as in Comparative Example 1 except that the electron beam irradiation dose was changed to 5, 30 Mrad, and the amount of residual monomer was determined and evaluated. The results are shown in Table 1.
<Example 5>
After forming the charge generation layer in Example 1, 10 parts of a styryl compound of the following structural formula (2) and 10 parts of a polycarbonate resin having a repeating unit of the following structural formula (3) were mixed with 50 parts of monochlorobenzene and dichloromethane 30. Dissolved in a portion of the mixed solvent to prepare a coating for the charge transport layer. This paint was applied onto the charge generation layer by a dip coating method and dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 15 μm.

  Next, 60 parts of the hole transporting compound monomer of the structural formula (1) was dissolved in a mixed solvent of 50 parts of monochlorobenzene and 50 parts of dichloromethane to prepare a protective layer coating material. This paint was applied onto the charge generation layer by a dip coating method, and this coating film was irradiated with an electron beam under an atmosphere having an oxygen concentration of 10 ppm and an acceleration voltage of 150 kV and an irradiation dose of 10 Mrad. Subsequently, a heat treatment was carried out for 10 minutes under the same atmosphere at a temperature of 80 ° C. to form a protective layer having a thickness of 5 μm to obtain an electrophotographic photoreceptor.

When the protective layer of the obtained photoconductor for measurement was peeled off and the amount of residual monomer contained in the protective layer was measured, it was 0.43% by mass with respect to the total weight of the protective layer.
<Examples 6 to 8>
An electrophotographic photosensitive member was prepared in the same manner as in Example 5 except that the heating conditions after electron beam irradiation were changed to 100 ° C., 130 ° C., and 160 ° C., and the residual monomer amount was determined and evaluated. The results are shown in Table 1.
<Comparative example 4>
An electrophotographic photosensitive member was prepared in the same manner as in Example 5 except that heating after electron beam irradiation was not performed, and the amount of residual monomer was determined and evaluated. The results are shown in Table 1.
<Examples 9 to 11>
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 5 except that the hole transporting compound monomer (1) was changed to the hole transporting compound monomers represented by the following structural formulas (4) to (6). The results are shown in Table 1.

<Comparative Examples 5-7>
An electrophotographic photosensitive member was prepared in the same manner as in Examples 9 to 11 except that the electron beam irradiation conditions in Examples 9 to 11 were changed to 20 Mrad and heating after irradiation was not performed, and the amount of residual monomer was determined and evaluated. did. The results are shown in Table 1.
< Reference Example 1 >
After forming the charge transport layer in Example 4, 60 parts of the hole transport compound monomer of the structural formula (1) and 3 parts of each of the photopolymerization initiators of the following structural formulas (7) and (8) were added to monochlorobenzene. It dissolved in the mixed solvent of 50 parts and 30 parts of dichloromethane, and prepared the coating material for protective layers. This paint was applied onto the charge generation layer by dip coating, and ultraviolet rays were applied to the coating film at a light intensity of 1600 W / m ² using a metal halide lamp in an atmosphere having an oxygen concentration of 10 ppm.
Irradiation was for 0 seconds to cure the coating film. Subsequently, a heat treatment was carried out for 10 minutes under the same atmosphere at a temperature of 120 ° C. to form a protective layer having a thickness of 5 μm to obtain an electrophotographic photoreceptor. The amount of residual monomer was determined and evaluated in the same manner as in Example 1. The results are shown in Table 1.

  As shown in Comparative Example 1 and Comparative Examples 3 to 7 in Table 1, the electrophotographic photosensitive member having a residual monomer amount larger than 1% by mass with respect to the solid content of the surface layer had almost good characteristics at normal temperature and humidity. However, with respect to image characteristics and cleaning characteristics under more severe high temperature and high humidity, image flow and blade turning have occurred. Note that the turning of the blade means that the cleaning blade is inverted and cannot be durable. Further, in the electrophotographic photosensitive member having the residual monomer amount shown in Comparative Example 2, blade turning occurred even under normal temperature and humidity.

  On the other hand, as shown in the examples, by setting the amount of residual monomer with respect to the solid content of the surface layer to 1% by mass or less, problems such as image flow and blade turning occur even under severer high temperature and high humidity. A clear image could be obtained until the end of the 10,000 sheet durability.

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

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Axis 3 Primary charging means 4 Image exposure light 5 Developing means 6 Transfer means 7 Transfer material 8 Image fixing means 9 Cleaning means 10 Pre-exposure light 11 Process cartridge 12 Rail

Claims (9)

In an electrophotographic photosensitive member having a conductive support and a photosensitive layer provided on the conductive support,
Surface layer forming the surface of the electrophotographic photosensitive member is formed by polymerizing a hole-transporting compound monomer having two or more chain polymerizable functional groups,
The content of the hole-transporting compound monomer, an electrophotographic photosensitive member, characterized in that more than 0.5% by weight, based on the total weight of the surface layer remaining on the surface layer. The electrophotographic photoreceptor according to claim 1, wherein the hole transporting compound monomer is represented by the following structural formula (1).

The electrophotographic photosensitive member according to claim 1, wherein the hole transporting compound monomer is represented by the following structural formula (4), (5) or (6).

The electrophotographic photosensitive member according to claim 1, wherein the surface layer is a protective layer provided on the photosensitive layer . 4. The electron according to claim 1, wherein the photosensitive layer includes a charge generation layer and a charge transport layer provided on the charge generation layer, and the surface layer is the charge transport layer. Photoconductor . The electrophotographic photoreceptor according to any one of claims 1 to 5, wherein the surface layer is formed by irradiating the hole transporting compound monomer with radiation to polymerize the hole transporting compound monomer. . The electrophotographic photosensitive member according to claim 6, wherein the radiation is an electron beam . 8. The electrophotographic photosensitive member according to claim 1, charging means for charging the electrophotographic photosensitive member, and development for developing an electrostatic latent image formed on the charged electrophotographic photosensitive member. A process cartridge mounted on an electrophotographic apparatus having means and a cleaning means for removing toner from the surface of the electrophotographic photosensitive member,
The electrophotographic photosensitive member and at least one means selected from the group consisting of the charging means, the developing means, and the cleaning means are integrally supported and configured to be detachable from the main body of the electrophotographic apparatus. Feature process cartridge . 8. The electrophotographic photosensitive member according to claim 1, charging means for charging the electrophotographic photosensitive member, and exposure for forming an electrostatic latent image on the charged electrophotographic photosensitive member by exposure.
Means, developing means for developing the electrostatic latent image formed on the electrophotographic photosensitive member with toner, and transfer means for transferring the toner image formed on the electrophotographic photosensitive member to a transfer material. An electrophotographic apparatus .

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