JP4418600B2 - Method for producing electrophotographic photosensitive member - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an electrophotographic photoreceptor.Manufacturing methodSpecifically, the electrophotographic photosensitive member is excellent in durability such as wear resistance, has high quality in initial image quality, and has high image uniformity even during repeated use over a long period of time.Manufacturing methodAbout.
[0002]
[Prior art]
  One representative image holding member is an electrophotographic photosensitive member. In recent years, electrophotographic technology has been widely used and applied not only in the field of copying machines but also in the field of various printers because of its immediacy and high-quality images. The core electrophotographic photoreceptors include inorganic materials such as selenium, cadmium sulfide, and zinc oxide. In recent years, however, there are no pollution, high productivity, ease of material design, and future prospects. From this point, organic materials have been actively developed.
[0003]
  In organic electrophotographic photoreceptors, it is usual to use an organic photoconductive substance dissolved or dispersed in a binder resin to form a coating film. The coating film is formed by dissolving or dispersing the organic photoconductive substance and the binder resin in a solvent and then applying and drying. As the binder resin, materials such as vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride and copolymers thereof, polycarbonate, polyester, polyarylate, polysulfone, phenoxy resin, epoxy resin, silicone resin, and the like are used. Yes.
[0004]
  These electrophotographic photoreceptors are naturally required to have various characteristics such as electrical, mechanical and optical characteristics according to the applied electrophotographic process. In particular, in electrophotographic photoreceptors that are repeatedly used, electrical and mechanical forces such as charging, exposure, development, transfer, and cleaning are repeatedly applied directly or indirectly, and thus durability against them is required. . The organic electrophotographic photosensitive member has many advantages over the inorganic electrophotographic photosensitive member in many aspects, but because of insufficient mechanical strength, various studies have been made on these issues. It was.
[0005]
  As one attempt to improve the durability of the organic electrophotographic photosensitive member, the mechanical strength of the resin used for the uppermost layer of the electrophotographic photosensitive member has been improved. As a technique to improve the resin strength,
(1) Use a resin having high mechanical strength as a property of the resin.
(2) Incorporate into the resin using a composition having high mechanical strength,
(3) Increasing the molecular weight of the resin having the same composition and using a resin having a high molecular weight.
Etc. were done.
[0006]
  Further, as another method for improving the wear resistance, attempts have been made to add fine particles to the charge transport layer of the electrophotographic photosensitive member, thereby improving the durability of the electrophotographic photosensitive member. The fine particles used are inorganic fine particles such as silica, alumina and chart, and organic resin fine particles such as fluorine resin fine particles and polystyrene fine particles.
[0007]
  However, as a harmful effect of adding fine particles, the fine particles generally have a strong tendency to agglomerate in the resin solution, and uniform dispersion is difficult. Conventionally used electrophotographic photoreceptor materials and methods have problems with the dispersibility, agglomeration, and transparency of fine particles in the binder resin, and image degradation is likely to occur due to non-uniformity and unevenness of the charge transport layer. . In addition, when a dispersion liquid in which fine particles are dispersed to stand for producing an electrophotographic photosensitive member is allowed to stand, secondary aggregation or sedimentation occurs with time even if temporarily dispersed immediately after the dispersion step. A uniformly dispersed state could not be maintained, and it was difficult to stably form a uniform coating film during mass production.
[0008]
  Furthermore, in order to improve dispersibility and dispersion stability, a method of adding a dispersion aid such as a surfactant has been used. However, the addition of a dispersion aid is an electrophotographic property (image quality, potential stability, etc.). Therefore, it is necessary not to use a dispersion aid used at the time of dispersion or to suppress the amount of use as much as possible. Accordingly, there has been a demand for the development of a technique having good electrophotographic characteristics and having fine particle dispersibility and dispersion stability.
[0009]
  Thus, in order to achieve high durability of the electrophotographic photosensitive member, the fine particles are added to the electrophotographic photosensitive member while avoiding the use of a dispersion aid as much as possible, and the fine particles are uniformly dispersed in the resin. There has been a demand for the development of a technique for holding and preventing secondary aggregation and sedimentation.
[0010]
[Problems to be solved by the invention]
  An object of the present invention is to provide an electrophotographic photosensitive member having a high mechanical strength and a high-quality image so that it can be used repeatedly over a long period of time, and has stable characteristics without impairing image quality even in long-term use. PhotoconductorManufacturing methodIs to provide.
[0011]
  Another object of the present invention is to provide an electrophotographic photoreceptor having improved production stability by suppressing secondary aggregation of fine particles during production.Manufacturing methodIs to provide.
[0012]
[Means for Solving the Problems]
  According to the present invention, a conductive support and a photosensitive layer formed on the conductive support are provided.ShiThe photosensitive layer is a laminated type photosensitive layer having a charge generation layer and a charge transport layer, and the charge transport layerIs electricAn electrophotographic photosensitive member which is the outermost layer of the child photographic photosensitive memberHow to manufactureIn
  Chlorobenzene,
  Fluorine resin fine particles,
  Dispersing aid for fluorine resin fine particles,And
  As a structural unitThe following general formula (2) And the weight average molecular weight (Mw) is150,000-200000Inherent viscosity (ηinh .: measured using tetrachloroethane as a solvent and a resin concentration of 1.0 g / dl at 25 ° C.)1.1-1.4Polyarylate resin
ContainsThe charge transport layer is formed using the charge transport layer coating solution,
  The amount of the dispersion aid in the charge transport layer coating solution is 3% by mass of the fluororesin fine particles,
  The amount of the fluororesin fine particles in the charge transport layer coating solution is 10% by mass or more of the solid content of the charge transport layer coating solution.
An electrophotographic photosensitive memberManufacturing methodIs provided.
[0013]
[Chemical 2]
[0017]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described in detail.
[0018]
  The present invention provides a charge transport layer constituting the outermost layer of an electrophotographic photoreceptor.
  Fluorine resin fine particlesAs well as
  The following general formula (1)
[6]
{In General Formula (1), X is -CR ₅ R ₆ -(R ₅ And R ₆ Are the same or different and are a hydrogen atom, a trifluoromethyl group, an alkyl group having 1 to 3 carbon atoms, or a phenyl group. ), A cycloalkylidene group, a single bond, an ether bond, a thioether bond or a sulfonyl bond. R ₁ ~ R ₄ Are the same or different and each represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. }
And a structural unit represented byWeight average molecular weight(Mw) is100,000 or moreAnd the inherent viscosity (ηinh .: tetrachloroethane as the solvent, the resin concentration is 1.0 g / dl, measured at 25 ° C.) is 0.8 or more.Polyarylate resin
TheContainThus, high mechanical strength is achieved, and resin fine particles are uniformly dispersed in the resin to provide a high-quality image and to obtain stable characteristics even during repeated use.
[0019]
  Hereinafter, “a polyarylate resin having a weight average molecular weight (Mw) of 100,000 or more” means “a weight average molecular weight (Mw) of 100,000 or more and an inherent viscosity (ηinh .: tetrachloroethane as a solvent)., TreeA polyarylate resin having a fat concentration of 1.0 g / dl and measured at 25 ° C. of 0.8 or more is used.
[0020]
  Among the structures of the general formula (1), the structural unit represented by the general formula (2), the general formula (3), or the general formula (4)HaveBy using a polyarylate resin having a weight average molecular weight (Mw) of 100,000 or more, not only the mechanical strength is improved, but also the productivity of the electrophotographic photosensitive member is improved by improving the solubility of the resin. It is possible.
[0021]
[Chemical7]
[0022]
  Further, even when a polyarylate resin having a weight average molecular weight (Mw) of 100,000 or more obtained by copolymerizing the structural units represented by the general formula (2), the general formula (3) or the general formula (4) is used, the same applies. It is possible to achieve improved mechanical strength and improved solubility.
[0023]
  Further, by adding fine particles, which is a technique for enhancing the durability of the electrophotographic photosensitive member, that is, by adding the fluororesin fine particles in the present invention to the photosensitive layer, it is possible to further enhance the durability.
[0024]
  In the examination of the present invention, the mechanical strength of the electrophotographic photosensitive member is obtained by having the fluororesin fine particles and the polyarylate resin {general formula (1)} having a weight average molecular weight (Mw) of 100,000 or more in the charge transport layer. Improvement was achieved. Furthermore, image defects of electrophotographic photosensitive members using fluororesin fine particles are often caused by non-uniformity or unevenness of the dispersion state in the charge transport layer of fluororesin fine particles. When the dispersion liquid in which fine particles are dispersed is allowed to stand to produce an electrophotographic photoreceptor, secondary aggregation or sedimentation of the resin fine particles, and when the liquid is flowed during coating, the liquid takes a share. This may be due to the change in dispersion state or secondary aggregation. As a result, the uniform dispersion state of the fine particles could not be maintained, and it was difficult to form a stable uniform coating film. However, the weight average molecular weight (Mw) used in the present invention was 100,000 or more. When used together with an arylate resin, suppression of image defects was observed.
[0025]
  Furthermore, using low molecular weight polyarylate resin, fluorinesystemWhen the content ratio of the resin fine particles is increased, image defects due to poor dispersion or re-aggregation of the resin fine particles tend to occur, and a dispersion aid such as a surfactant is used to prevent poor dispersion and re-aggregation. When a large amount of the agent is added, there is a tendency that an image density is lowered during repeated use. However, when a polyarylate resin having a weight average molecular weight (Mw) of 100,000 or more is used and the content ratio of the fluororesin fine particles is increased, the dispersibility of the dispersion aid is kept low even though the addition amount of the dispersion aid is kept low. There was no image defect due to reduction or dispersion stability (secondary agglomeration), and since the amount of dispersion aid added was suppressed, no adverse effects such as image density reduction during repeated use were observed.
[0026]
  An attempt to increase the durability of the electrophotographic photosensitive member by forming the charge transport layer of the electrophotographic photosensitive member from polyarylate resin and fluororesin fine particles is also made in Japanese Patent Application Laid-Open No. 9-319129. In the examples in this publication, a polyarylate resin having a weight average molecular weight (Mw) of about 30,000 is used, and fluorine resin fine particles are added in an amount of 10% by mass to 30% by mass of the solid content of the charge transport layer coating solution. An example is shown. The dispersion aid at this time is added by 4% by mass of the fluororesin fine particles, and it is shown that a good initial image can be provided with good dispersibility. However, an attempt was made to lower the mass ratio of the dispersion aid to the fine particles in order to ensure better image quality without causing a decrease in density during repeated use. As a result, it was used in the examples of JP-A-9-319129. The polyarylate resin having a weight average molecular weight (Mw) of about 30,000 is used, the mass ratio of the dispersion aid is 3%, and the fluororesin fine particles are 10 mass of the solid content of the charge transport layer coating solution. In the case where the ratio was not less than%, initial image deterioration due to poor dispersion was confirmed.
[0027]
  This means that in the case of a polyarylate resin having a weight average molecular weight of about 30,000, both the durability improvement of the electrophotographic photosensitive member and a good image can be achieved by including 10 mass% or more of fluorine-based resin fine particles in the charge transport layer. It is difficult to do. For this purpose, a polyarylate resin having a weight average molecular weight (Mw) of about 100,000 is used, the mass ratio of the dispersion aid is 3%, and the fluororesin fine particles are 10% of the solid content of the charge transport layer coating solution. In the case of the mass% or more, the initial image was not deteriorated due to poor dispersion, and the density reduction during repeated use could be suppressed to a low level. This indicates that when a polyarylate resin having a weight average molecular weight (Mw) of about 100,000 is used, it is possible to achieve both improved durability of the electrophotographic photosensitive member and good images.
[0028]
  Although the specific mechanism of the effect of improving the dispersibility and dispersion stability of the polyarylate resin having a weight average molecular weight (Mw) of 100,000 or more has not been sufficiently elucidated, the weight average molecular weight (Mw) is 100,000. When the polyarylate resin as described above is used, the viscosity of the electrophotographic photoreceptor coating solution in which the resin is dissolved in a solvent is higher than that when a conventional polyarylate resin is used under the same conditions, and the coating solution is The reason is that, due to the reasonably high viscosity, the dispersion state of the fluororesin fine particles is stabilized, and further the retention ability of the dispersion state is improved. Conceivable.
[0029]
  When a polyarylate resin having a relatively small weight average molecular weight (weight average molecular weight smaller than 100,000) is used and the viscosity of the coating liquid is increased to improve the dispersion stability, the coating liquid is inevitably produced. However, in this case, since the coating is performed at a lower speed in the production stage in which an appropriate film thickness of the photosensitive layer is applied, it is not suitable for mass production. By using a large polyarylate resin having a weight average molecular weight (Mw) of 100,000 or more, it is possible to maintain the productivity and increase the dispersion stability.
[0030]
  In the study on the particle size of the fluororesin fine particles, when the fine particle of the fluororesin fine particles is larger than 0.5 μm, the liquid storage stability of the coating liquid after the fine particle dispersion becomes worse, This causes fine particles to settle, resulting in image defects that appear to be due to uneven dispersion or secondary aggregation. Even with fluororesin fine particles having a particle diameter larger than 0.5 μm, precipitation and secondary aggregation were suppressed by using a polyarylate resin having a weight average molecular weight (Mw) of 100,000 or more and a dispersion aid. However, it did not necessarily satisfy all the conditions for a good image. However, when fluorine-based resin fine particles having a particle size of 0.3 μm or less are used and a combination of a polyarylate resin having a weight average molecular weight (Mw) of 100,000 or more and a dispersion aid is used, the fine particles are dispersed. No fine particles settled or secondary aggregation occurred when the coating solution was allowed to stand, and a good initial image was obtained. In this case, when a polyarylate resin having a large weight average molecular weight of 100,000 or more is used, the dispersion state of the fluororesin fine particles is stabilized and the dispersion state retention ability is improved by appropriately increasing the viscosity of the coating liquid. It is considered that one of the reasons is that the effect of doing is acting.
[0031]
  Although the preferable example of the structural unit of the polyarylate resin which has a structural unit shown by General formula (1) used for this invention below is shown below, it is not limited to these.
[0032]
[Table 1]
[0033]
[Table 2]
[0034]
  In particular, the polyarylate resin represented by the structural unit example (1), the structural unit example (2), or the structural unit example (3) is preferable in terms of mechanical strength and solubility in a solvent.
[0035]
  Moreover, in order to add other characteristics, such as intensity | strength and solubility, it is also possible to set it as the copolymer with bisphenol of another structure. For example, when the polyarylate resin represented by the general formula (3) is copolymerized with the polyarylate resin represented by the general formula (2), the polymerization ratio is 5/95 to 95/5, respectively. It is possible to extract the characteristics of
[0036]
  Furthermore, it is also possible to blend with polyarylate or polycarbonate of other structure in order to improve productivity. For example, when the polyarylate resin represented by the general formula (3) is blended with the polyarylate resin represented by the general formula (2), the mixing ratio (mass ratio) is the formula (2) / formula (3) = 5. 20/80 to 80/20 is preferable in order to achieve the effect of the present invention efficiently.
[0037]
  The molecular weight of the resin has a weight average molecular weight (Mw) of 100,000 or more from the viewpoints of mechanical strength, dispersion stability of fluororesin fine particles, and dispersion retention. However, if the weight average molecular weight is too large, the viscosity of the coating solution becomes too high and the productivity is lowered. Therefore, a polyarylate resin having a weight average molecular weight (Mw) of 100,000 to 250,000 is preferable.
[0038]
  The fluororesin fine particles have at least a composition selected from tetrafluoroethylene resin, chlorotrifluoroethylene resin, hexafluoroethylenepropylene resin, vinyl fluoride resin, vinylidene fluoride resin, dichlorodifluoroethylene resin, and copolymers thereof. Fine particles made of one kind of resin are preferable.
[0039]
  In order to ensure a good image quality, the average particle size of the resin fine particles is preferably 0.3 μm or less, and particularly preferably the average particle size is 0.1 μm or less, from the above-mentioned matters.
[0040]
  Hereinafter, the configuration of the electrophotographic photosensitive member of the present invention will be described.
[0041]
  The electrophotographic photosensitive member of the present invention is applied to a laminated type having a charge transport layer containing a charge transport material and a charge generation layer containing a charge generation material.
[0042]
  As the charge generation material in the present invention, commonly known materials can be used, for example, selenium-tellurium, pyrylium dyes, thiopyrylium dyes, metal phthalocyanine pigments, metal-free phthalocyanine pigments, anthanthrone pigments. And dibenzpyrenequinone pigments, pyranthrone pigments, trisazo pigments, disazo pigments, azo pigments, indigo pigments, quinacridone pigments, and cyanine pigments. These pigments can be sufficiently used by using a homogenizer, ultrasonic dispersion, ball mill, vibration mill, sand mill attritor, roll mill or liquid collision type high-speed disperser together with a binder resin and a solvent having a mass of 0.3 to 4 times. A dispersed dispersion is obtained. In the case of a laminated electrophotographic photoreceptor, a charge generation layer is obtained by applying this solution and drying. The film thickness is preferably 5 μm or less, and particularly preferably 0.1 to 2 μm.
[0043]
  Charge transport materials are broadly classified into electron transport materials and hole transport materials. Examples of electron transport compounds include 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, chloranil, tetra Examples thereof include electron accepting compounds such as cyanoquinodimethane and alkyl-substituted diphenoquinone, and those obtained by polymerizing these electron accepting compounds. Examples of the hole transporting compound include polycyclic aromatic compounds such as pyrene and anthracene, heterocyclic compounds such as carbazole, indole, oxazole, thiazole, oxathiazole, pyrazole, pyrazoline, thiadiazole and triazole, p-diethylaminobenzaldehyde-N, Hydrazone compounds such as N-diphenylhydrazone and N, N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, α-phenyl-4′-N, N-diphenylaminostilbene and 5- (4- (di- p-tolylamino) benzylidene) -5H-dibenzo (a, d) styryl compounds such as cycloheptene, benzidine compounds and triarylamine compounds, or polymer compounds having groups of these compounds in the main chain or side chain ( Poly-N- Alkenyl carbazole and polyvinyl anthracene and the like). These compounds are dissolved in a solvent together with a binder resin to form a solution. In the case of a multilayer electrophotographic photoreceptor, a charge transport layer is obtained by applying this solution and drying. The film thickness is preferably 5 to 40 μm, and particularly preferably 15 to 30 μm.
[0044]
  The charge transport material used for the charge transport layer is preferably 20 to 70% by mass with respect to the solid content of the charge transport layer. If it is less than 20% by mass, it is difficult to obtain a sufficient charge transfer capability, and therefore an increase in residual potential is likely to occur. If it exceeds 70% by mass, the mechanical strength of the charge transport layer tends to be low, so that sufficient durability is difficult to obtain.
[0045]
  The binder resin used in the charge transport layer is preferably 20 to 80% by mass with respect to the solid content of the charge transport layer. If it exceeds 80% by mass, it is difficult to obtain a sufficient charge transfer capability, so that an increase in residual potential, a decrease in electrical durability, a reduction in the effect of reducing the surface energy, and the like are likely to occur. If it is less than 20% by mass, the mechanical strength of the charge transport layer tends to be lowered, so that sufficient durability is difficult to obtain.
[0046]
  A dispersion aid may be used when the above-described fluororesin fine particles are dispersed in a polyarylate resin having a weight average molecular weight of 100,000 or more. As the dispersion aid, a fluorine-based surfactant is preferable. Specifically, as a fluorine-based surfactant,
X-SO₂NRCH₂COOH,
X-SO₂NRCH₂CH₂O (CH₂CH₂O)_nH (n = 5, 10, 15),
X-SO₂N (CH₂CH₂CH₂OH)₂,
X-RO (CH₂CH₂O)_n  (N = 5, 10, 15),
X- (RO)_n  (N = 5-20),
X- (RO)_nR (n = 5-20),
X-COOH, X-CH₂CH₂COOH, X-ORCOOH, X-ORCH₂COOH,
X-SO₃H, X-ORSO₃H, X-CH₂CH₂OH,
[0047]
[Chemical8]
X-CH, a graft polymer surfactant having X- in the side chain₂X-CH, a graft polymer type surfactant having-in the side chain₂CH₂X-CH, a graft polymer type surfactant having-in the side chain₂CH₂Examples thereof include a graft polymer type surfactant having OCO- in the side chain. However, R in a formula shows an alkyl group, an allyl group, or an aralkyl group, X is -CF₃, -C₄F₉Or -C₈F₁₇Fluorocarbon group such as
[0048]
  Examples of the dispersion method of the fluororesin fine particles include a homogenizer, a ball mill, a sand mill, a roll mill, and an ultrasonic wave. However, the dispersion method is not particularly limited as long as it can be dispersed to a primary particle size.
[0049]
  In the present invention,ConductiveIf necessary, an intermediate layer having an adhesion function and a charge barrier function can be provided between the support and the photosensitive layer, or between the conductive layer and the photosensitive layer. Examples of the material for the intermediate layer include casein, polyvinyl alcohol, polyvinyl butyral, nitrocellulose, ethyl cellulose, ethylene-acrylic acid copolymer, polyethylene oxide, phenol resin, polyamide, polyurethane, polyether urethane, and gelatin. These are dissolved in a solvent, applied and dried. The thickness of the intermediate layer is preferably 0.05 to 5 μm, and particularly preferably 0.2 to 1 μm.
[0050]
  In addition to the above compounds, additives can be used for the photosensitive layer in order to improve mechanical properties and durability. Examples of such additives include antioxidants, ultraviolet absorbers, stabilizers, crosslinking agents, lubricants, and conductivity control agents.
[0051]
  There is no limitation on the application method of these electrophotographic photosensitive members, and generally known means such as a dip coating method, a spray coating method, and a bar coating method can be used.
[0052]
  FIG. 1 shows a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.
[0053]
  In FIG. 1, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is rotationally driven around a shaft 2 in the direction of an arrow at a predetermined peripheral speed. In the rotating process, the electrophotographic photosensitive member 1,bandTime series electric digital of the target image information output from exposure means (not shown) such as slit exposure and laser beam scanning exposure, etc. Exposure light 4 that is enhanced and modulated in response to an image signal is received. In this way, electrostatic latent images corresponding to the target image information are sequentially formed on the peripheral surface of the electrophotographic photoreceptor 1.
[0054]
  The formed electrostatic latent image is then developed with toner by the developing means 5 and is taken out from a paper feeding unit (not shown) between the electrophotographic photoreceptor 1 and the transfer means 6 in synchronism with the rotation of the electrophotographic photoreceptor 1. The toner images formed and supported on the surface of the electrophotographic photosensitive member 1 are sequentially transferred by the transfer means 6 onto the transferred transfer material 7.
[0055]
  The transfer material 7 that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member, introduced into the image fixing means 8, and subjected to image fixing to be printed out as an image formed product (print, copy). .
[0056]
  Toner imageimageTheTranscriptiondidThe surface of the subsequent electrophotographic photosensitive member 1 is cleaned by removing the transfer residual toner by the cleaning unit 9, and after being subjected to the charge removal process by the pre-exposure light 10 from the pre-exposure unit (not shown), the surface is repeated. Used for image formation. In addition,bandWhen the electric means 3 is a contact charging means using a charging roller or the like, pre-exposure is not necessarily required.
[0057]
  In the present invention, the above-described electrophotographic photoreceptor 1,bandAmong the constituent elements such as the electric 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 is an electronic device such as a copying machine or a laser beam printer. You may comprise so that attachment or detachment with respect to the photographic apparatus main body is possible. For example,bandAt least one of the electric means 3, the developing means 5, and the cleaning means 9 is integrally supported together with the electrophotographic photosensitive member 1 to form a cartridge, and the guide means 12 such as a rail of the apparatus main body is used.Electronic photographyThe process cartridge 11 can be detachably attached to the apparatus main body.
[0058]
  Further, when the electrophotographic apparatus is a copying machine or a printer, the exposure light 4 is reflected or transmitted light from the original, or the original is read by a sensor and converted into a signal, and a laser beam scanning performed according to this signal is performed. The light emitted by driving the LED array or the liquid crystal shutter array.
[0059]
  The electrophotographic photosensitive member of the present invention can be used not only for electrophotographic copying machines but also widely applicable to electrophotographic application fields such as laser beam printers, CRT printers, LED printers, FAX, liquid crystal printers, and laser plate making. It is.
[0060]
【Example】
  Hereinafter, the present invention will be described in more detail with reference to specific examples. In addition, "part" in an Example shows a mass part.
[0061]
  (referenceExample 1)
  On a 30φ × 357 mm aluminum cylinder, a coating liquid composed of the following materials was applied by a dip coating method and thermally cured at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 15 μm.
[0062]
  Conductive pigment: SnO₂Coated barium sulfate 10 parts
  Resistance adjustment pigment: Titanium oxide 2 parts
  Binder resin: 6 parts of phenol resin
  Leveling material: 0.001 part of silicone oil
  Solvent: methanol / methoxypropanol = 2/8 (mass ratio) 20 parts
[0063]
  Next, a solution obtained 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 is applied onto this conductive layer by a dip coating method and dried. As a result, an intermediate layer having a thickness of 0.5 μm was formed.
[0064]
  Next, 4 parts of an azo pigment represented by the following structural formula:
[0065]
[Chemical9]
[0066]
Disperse 2 parts of polyvinyl butyral (trade name: ESREC BLS, manufactured by Sekisui Chemical Co., Ltd.) and 35 parts of cyclohexanone for 12 hours in a sand mill using 1 mmφ glass beads, and then add 60 parts of methyl ethyl ketone to prepare a dispersion for a charge generation layer. did. This dispersion was applied onto the intermediate layer by a dip coating method and dried to form a charge generation layer having a thickness of 0.3 μm.
[0067]
  Next, 4 parts of polytetrafluoroethylene particles having an average primary particle size of 0.3 μm and 0.16 part of a fluorosurfactant (trade name: Aron GF300, manufactured by Toagosei Co., Ltd.) as a dispersion aid (based on fluororesin fine particles) 4 mass%), a weight average molecular weight (Mw) of 150,000 and an inherent viscosity of 1.1, 80 parts of chlorobenzene are added to 8 parts of the polyarylate resin having the structure of the structural unit example (1), and fluorinesystemA resin fine particle dispersion was prepared. In this dispersion, 7 parts of an amine compound having the following structural formula as a charge transport material,
[0068]
[Chemical10]
[0069]
  1 part of an amine compound of the structural formula
[0070]
[Chemical11]
[0071]
Was added to obtain a coating solution for the charge transport layer. This coating solution was applied by a dip coating method and dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 27 μm. The production conditions are shown in Table 1.
[0072]
  Next, evaluation will be described. For evaluation, Canon Co., Ltd., copy machine GP40 (AC / DC charging system in which a DC voltage superimposed with an AC voltage is applied from a charging member placed in contact with the electrophotographic photosensitive member to charge the electrophotographic photosensitive member) is used. It was. The dark part potential Vd = −700V and the bright part potential Vl = −200V. 10,000 sheets were copied in an intermittent mode in which A4 size plain paper was stopped once for each copy, and then the wear amount of the electrophotographic photosensitive member film thickness was measured. Also, the presence or absence of image defects due to initial dispersion failure was observed. The evaluation method is to visually measure the number of image defects due to poor dispersion on the entire surface of A3 paper that has been output using an electrophotographic photosensitive member. When there is no image defect: ○, when there are 1 to 2 defects: Δ, In the case of 3 or more: evaluated as x. Further, the aggregation of the fine particles after the charge transport layer coating solution was allowed to stand in a dark place at room temperature for 1 month was also observed. The evaluation method is to evaluate the difference between the average particle size before standing (particle size distribution meter: measured by Horiba, CAPA700) and the average particle size after standing for 1 month, and when the particle size difference is less than 0.2 μm: When there was no aggregation and the average particle size difference was less than 0.2 to 0.5 μm: slightly aggregated, when the average particle size difference was 0.5 μm or more: it was evaluated that there was aggregation. The results are shown in Table 2.
[0073]
  (Example 25 and Reference Example 6-14)
  An electrophotographic photosensitive member was produced under the conditions shown in Table 1 (except that the conditions shown in Table 1 were changed).referenceThe same as in Example 1) was evaluated. The results are shown in Table 2.
[0074]
  (Comparative Examples 1-4)
  As a resin constituting the charge transport layer, a polyarylate resin comprising the structural unit example (1) having a weight average molecular weight (Mw) of 40,000 and an inherent viscosity of 0.5 is used. Body (except for changing the conditions shown in Table 1)referenceThe same as in Example 1) was evaluated. The results are shown in Table 2.
[0075]
  (Comparative Examples 5-7)
  As a resin constituting the charge transport layer, an electrophotographic photosensitive member was produced under the conditions shown in Table 1 using a polycarbonate resin composed of a structural unit of the general formula (5) having a weight average molecular weight (Mw) of 40,000 (Table 1). Except for changing the condition of 1referenceThe same as in Example 1) was evaluated. The results are shown in Table 2.
[0076]
[Chemical12]
[0077]
[Table 1]
[0078]
[Table 2]
[0079]
  (Example 15)
  4 parts of polytetrafluoroethylene particles having an average primary particle size of 0.1 μm as fluororesin fine particles used in the charge transport layer and a fluorosurfactant (trade name: Aron GF300, manufactured by Toagosei Co., Ltd.) 0.12 as a dispersion aid A charge transport layer coating solution and an electrophotographic photosensitive member were prepared in the same manner as in Example 2 except that 3 parts by weight (3% by mass with respect to the fluororesin fine particles) was used.
[0080]
  Next, evaluation will be described. For evaluation, Canon Co., Ltd., copy machine GP40 (AC / DC charging system in which a DC voltage superimposed with an AC voltage is applied from a charging member placed in contact with the electrophotographic photosensitive member to charge the electrophotographic photosensitive member) is used. It was. The dark part potential Vd = −700V and the bright part potential Vl = −200V. The presence or absence of image defects due to initial dispersion failure was observed. The evaluation method is to visually measure the number of image defects due to poor dispersion on the entire surface of the A3 paper that has been output using an electrophotographic photosensitive member. When there is no image defect: ○, when there are 1 to 2 defects: Δ, In the case of 3 or more: evaluated as x. Further, the aggregation of the fine particles after the charge transport layer coating solution was allowed to stand in a dark place at room temperature for 1 month was also observed. The evaluation method evaluates the difference between the average particle size before standing (particle size distribution meter: measured by Horiba, CAPA700) and the average particle size after standing for one month, and when the particle size difference is less than 0.2 μm: aggregation None, when the average particle size difference was 0.2 to less than 0.5 μm: slightly aggregated, when the average particle size difference was 0.5 μm or more: evaluated as aggregated. The results are shown in Table 3.
[0081]
  (referenceExample 16)
  The resin constituting the charge transport layer is composed of copolymer {polymerization ratio (1) / (2) = 7/3} of structural unit examples (1) and (2) having a weight average molecular weight (Mw) of 200,000. 4 parts of polytetrafluoroethylene particles having an average primary particle size of 0.1 μm as polyarylate resin and fluororesin fine particles, and 0.12 part of fluorosurfactant (trade name: Aron GF300, manufactured by Toagosei Co., Ltd.) as a dispersion aid A charge transport layer coating solution and an electrophotographic photosensitive member were produced in the same manner as in Example 2 except that (3% by mass with respect to the fluororesin fine particles) was used, and evaluated in the same manner as in Example 15. The results are shown in Table 3.
[0082]
  (referenceExample 17)
  Structure of copolymer (polymerization ratio (1) / (3) = 7/3) of structural unit examples (1) and (3) having a weight average molecular weight (Mw) of 150,000 as the resin constituting the charge transport layer 4 parts of polytetrafluoroethylene particles having an average primary particle size of 0.1 μm as a fluorine-containing resin fine particle and a fluorine-containing surfactant (trade name: Aron GF300, manufactured by Toagosei Co., Ltd.) as a dispersion aid A charge transport layer coating solution and an electrophotographic photosensitive member were prepared in the same manner as in Example 2 except that 12 parts (3% by mass with respect to the fluororesin fine particles) were used, and evaluated in the same manner as in Example 15. did. The results are shown in Table 3.
[0083]
  (Comparative Examples 8 and 9)
  An electrophotographic photoreceptor was prepared under the conditions shown in Table 3 (same as Example 2 except that the conditions of Table 3 were changed), and evaluated in the same manner as Example 15. The results are shown in Table 3.
[0084]
[Table 3]
[0085]
  From Table 2, by using the electrophotographic photosensitive member of the present invention containing a polyarylate resin having a weight average molecular weight (Mw) of 100,000 or more and fluororesin fine particles in the charge transport layer, electrophotographic photosensitivity during repeated use is used. It has been shown that the durability of the body is improved and that a uniform image can be provided over a long period of time without deterioration of image quality in the initial use of the electrophotographic photosensitive member due to the poor dispersion. In particular, when high durability is achieved by using fluorine resin fine particles of 10% by mass or more of the solid content in the charge transport layer, the effect of using a polyarylate resin having a weight average molecular weight (Mw) of 100,000 or more is remarkable. As a result, it has become possible to achieve both improvement in durability and maintenance of high image quality, which were difficult with low molecular weight polyarylate. Further, even during long-term storage of the charge transport layer coating solution, secondary aggregation of the fluororesin fine particles is suppressed by using a polyarylate resin having a high molecular weight, and the dispersion does not change so that the electrophotography The production stability of the photoreceptor has also improved.
[0086]
  From Table 2 and Table 3, if the primary particle size of the fluororesin fine particles is 0.3 μm or less by using a polyarylate resin having a weight average molecular weight (Mw) of 100,000 or more, the solids of the fluororesin fine particles Even when the amount exceeds 10% by mass, secondary aggregation of the fluororesin fine particles is suppressed even during long-term storage of the coating solution for the charge transport layer, which was difficult with the low molecular weight polyarylate resin. It was revealed that a good image can be provided.
[0087]
  Therefore, an electrophotographic photoreceptor comprising a polyarylate resin having a weight average molecular weight (Mw) of 100,000 or more and an inherent viscosity of 0.8 or more and fluororesin fine particles in the charge transport layer of the present invention, and the electrophotographic photoreceptor. The superiority of the process cartridge and the electrophotographic apparatus having the same was shown.
[0088]
【The invention's effect】
  According to the present invention, the charge transport layer contains a polyarylate resin having a weight average molecular weight (Mw) of 100,000 or more and an inherent viscosity of 0.8 or more and fluororesin fine particles. Abrasion resistance is remarkably improved, durability during repeated use is improved, and high molecular weight resin is used to uniformly disperse fluororesin fine particles in the film, resulting in poor dispersion and secondary aggregation. It has become possible to provide an electrophotographic photosensitive member that can suppress the occurrence of unevenness due to the above and the like and provide a good image, a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.
[Explanation of symbols]
1 Electrophotographic photoreceptor
2 axis
3 Charging means
4 exposure light
5 Development means
6 Transfer means
7 Transfer material
8 Fixing means
9 Cleaning means
10 Pre-exposure light
11 Process cartridge
12 Guide means

Claims (3)

Have a conductive support and a photosensitive layer formed on the conductive support member, a photosensitive layer of the laminate type photosensitive layer has a charge generating layer and a charge transport layer, charge transport layer is electron photoreceptor In the method for producing an electrophotographic photoreceptor which is the outermost layer of
Chlorobenzene ,
Fluorine resin fine particles,
Dispersing aid for fluorine resin fine particles , and
As a structural unit, the following general formula ( 2 )
In having only the structural units represented, and the weight average molecular weight (Mw) of 150,000 to 200,000, and using tetrachloroethane as inherent viscosity (.eta.inh .: solvent, the concentration of the resin and 1.0 g / dl, 25 The charge transport layer is formed using a coating solution for a charge transport layer containing a polyarylate resin having a 1.1 to 1.4 ( measured at ° C.)
The amount of the dispersion aid in the charge transport layer coating solution is 3% by mass of the fluororesin fine particles,
The method for producing an electrophotographic photosensitive member , wherein the amount of the fluororesin fine particles in the charge transport layer coating solution is 10% by mass or more of the solid content of the charge transport layer coating solution . The fluorine resin particles, method for producing an electrophotographic photosensitive member according to claim 1 is polytetrafluoroethylene particles. The method for producing an electrophotographic photosensitive member according to claim 1 or 2 having an average primary particle diameter of the fluorine resin particles is 0.3μm or less.