JP2007094355A - Electrophotographic photoreceptor, process cartridge, and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which is imparted with a wear resistance to suppress the growth of a flaw, is excellent in solubility and stability of a coating liquid and hardly gives rise to the occurrence of a solvent crack. <P>SOLUTION: The electrophotographic photoreceptor having a polycarbonate resin on a surface layer is characterized in that the polycarbonate resin has a repeating unit expressed by formula (1) and a repeating unit expressed by formula (2) and has a glass transition temperature of ≤155°C. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrophotographic photoreceptor, a process cartridge, and an electrophotographic apparatus, and more specifically, an electrophotographic photoreceptor containing a specific polycarbonate resin in a surface layer, a process cartridge having the electrophotographic photoreceptor, and an electrophotographic apparatus. About.

  There is an electrophotographic photosensitive member as an image holding member used in an electrophotographic apparatus. From the viewpoint of high productivity, ease of material design, and future prospect, development of an organic electrophotographic photosensitive member using an organic photoconductive substance is actively performed. Has been done. With regard to functionality as an electrophotographic photosensitive member, an electrophotographic photosensitive member superior to that of an inorganic electrophotographic photosensitive member has been produced. However, the sensitivity of an organic electrophotographic photosensitive member is enhanced, and the stability of an image during repeated use is increased. Further improvement is desired in terms of durability.

  In order to satisfy the durability characteristics of the organic electrophotographic photoreceptor, a polycarbonate resin having a bisphenol A skeleton as a resin having good wear resistance and electrical characteristics often used for the surface layer has attracted attention. However, it is not possible to solve all the problems as described above, and has the following problems.

  (1) These solvents are poor in solubility, exhibit only good solubility in a part of halogenated aliphatic hydrocarbons such as dichloromethane and 1,2-dichloroethane, and these solvents have low boiling points. When the photoconductor is produced using the coating solution prepared in (1), the coated surface is likely to be whitened. Moreover, it takes time and effort to manage the solid content of the coating liquid.

  (2) Solvents other than halogenated aliphatic hydrocarbons are partially soluble in tetrahydrofuran, dioxane, cyclohexanone, or a mixed solvent thereof, but the solution gels in several days, etc. It is not suitable for photoconductor production due to poor properties.

  (3) Furthermore, even if the above (1) and (2) are improved, the electrophotographic photoreceptor containing a polycarbonate resin having bisphenol A as a skeleton in the surface layer is liable to generate solvent cracks.

  (4) In addition, in the conventional polycarbonate resin, the film formed of the resin has poor lubricity, the photoconductor is easily damaged, and image defects may occur.

  In order to solve these problems, polycarbonate resins having various structures have been developed, and polycarbonate resins produced from bisphenol having a fluorene structure have been proposed (see Patent Documents 1 and 2). ). By using these polycarbonate resins, the solubility and the stability of the coating solution are improved, but there is room for further improvement with respect to the solvent cracks.

As a method for improving scratches on the photoreceptor, a compound having excellent lubricity is added, a resin having a strength higher than that of a polycarbonate resin having a bisphenol A skeleton is used, or wear is imparted to the scratches. Examples include suppressing growth. However, when crack growth is suppressed by imparting wear properties to the surface layer of the photoreceptor, solvent cracks are likely to occur.
JP-A-6-3838 JP 2002-278100 A

  The present invention solves the problems as described above, suppresses the growth of scratches by imparting wear properties, is excellent in solubility and stability of the coating liquid, and is less prone to solvent cracks. The purpose is to provide.

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

The electrophotographic photoreceptor according to the present invention is:
An electrophotographic photoreceptor containing a polycarbonate resin in the surface layer,
The polycarbonate resin has the following formula (1)

(In the formula (1), each R ₁ independently represents an alkylene group having 2 to 10 carbon atoms, a cycloalkylene group having 6 to 20 carbon atoms, or an arylene group having 6 to 20 carbon atoms, R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.
A repeating unit represented by the following formula (2):

(In formula (2), X represents a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 5 to 20 carbon atoms, or the following formula (3):

The connection structure shown by is shown. )
And having a glass transition temperature of 155 ° C. or lower,
It is characterized by that.

  A process cartridge and an electrophotographic apparatus according to the present invention include the above-described electrophotographic photosensitive member.

  By imparting wearability, the growth of scratches is suppressed, the solubility and stability of the coating liquid are excellent, and solvent cracks are unlikely to occur.

  Hereinafter, the present invention will be described in detail. First, the polycarbonate resin used in the present invention will be described in detail.

  The polycarbonate resin contained in the surface layer of the electrophotographic photosensitive member has at least a repeating unit represented by the above formula (1) and a repeating unit represented by the above formula (2), and the glass transition temperature of the resin. Is 155 ° C. or lower.

Each R ₁ in the formula (1) is independently an alkylene group having 2 to 10 carbon atoms, a cycloalkylene group having 6 to 20 carbon atoms, or an arylene group having 6 to 20 carbon atoms. Examples of the alkylene group include an ethylene group, a propylene group, and a butylene group. Examples of the cycloalkylene group include a cyclohexylene group and a cycloheptylene group. Examples of the arylene group include a phenylene group and a naphthylene group. Etc. R ₁₁ , R ₁₂ , R ₁₃ and R _{14 in} formula (1) are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Examples of the alkyl group include a methyl group, an ethyl group, and a propyl group, and examples of the aryl group include a phenyl group and a naphthyl group.

  X in Formula (2) is a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 5 to 20 carbon atoms, or a linkage represented by Formula (3) above. Structure. Examples of the alkylene group include an ethylene group, a propylene group, and a butylene group. Examples of the cycloalkylene group include a cyclohexylene group and a cycloheptylene group.

  The polycarbonate resin of this invention is manufactured by making the dihydroxy compound and carbonic acid diester of following formula (6) and following formula (7) react in presence of a polymerization catalyst.

(In Formula (6), each R ₁ independently represents an alkylene group having 2 to 10 carbon atoms, a cycloalkylene group having 6 to 20 carbon atoms, or an arylene group having 6 to 20 carbon atoms, R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.

(In formula (7), X is a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 5 to 20 carbon atoms, or the following formula (3):

The connection structure shown by is shown. )

  The polycarbonate resin of the present invention is preferably synthesized by reacting the dihydroxy compound represented by the above formula (6) at a ratio of 30 mol% to 90 mol%, more preferably 30 mol% to 70 mol%. preferable. When the ratio of the dihydroxy compound represented by the formula (6) is larger than 90 mol%, the solubility is likely to deteriorate, and solvent cracks are more likely to occur. On the other hand, if it is less than 30 mol%, the compatibility with the charge transport material is deteriorated, so that potential fluctuations are likely to occur when it is used repeatedly.

  Specific examples of the dihydroxy compound represented by the formula (6) used in the present invention include the following compounds.

9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene 9,9-bis (4- (2-hydroxyethoxy) -3-methylphenyl) fluorene 9,9-bis (4- (2-hydroxy) Ethoxy) -3-isopropylphenyl) fluorene 9,9-bis (4- (2-hydroxyethoxy) -3-isobutylphenyl) fluorene 9,9-bis (4- (2-hydroxyethoxy) -3-tert-butyl Phenyl) fluorene 9,9-bis (4- (2-hydroxyethoxy) -3-cyclohexylphenyl) fluorene 9,9-bis (4- (2-hydroxyethoxy) -3-phenylphenyl) fluorene 9,9-bis (4- (2-hydroxyethoxy) -3,5-dimethylphenyl) fluorene 9,9-bis (4- (2-hydride) Kishietokishi) -3-tert-butyl-6-methylphenyl) fluorene 9,9-bis (4- (3-hydroxy-2,2-dimethyl) phenyl) fluorene

  Among these compounds, 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene is preferable in terms of solvent cracks.

  Specific examples of the dihydroxy compound represented by the formula (7) used in the present invention include the following compounds.

Tricyclodecane [5.2.1.02,6] dimethanol Pentacyclopentadecanedimethanol Cyclohexane-1,4-dimethanol Decalin-2,6-dimethanol Decalin-1,5-dimethanol Norbornane dimethanol 1, 4-butanediol 1,5-pentanediol 1,6-hexanediol 1,8-octanediol 1,9-nonanediol 1,10-decanediol spiroglycol

  Of these compounds, dihydroxy compounds having cycloalkylene are preferable in terms of compatibility with solvent cracks and charge transport materials. In particular, tricyclodecane [5.2.1.02,6] dimethanol and pentacyclopentadecane dimethanol are preferable in terms of compatibility with solvent cracks and charge transport materials.

  The polycarbonate resin in the present invention includes a random, block or alternating copolymer structure, and exhibits excellent solubility and solvent crack resistance.

  The polycarbonate resin of the present invention may be obtained by copolymerizing the dihydroxy compounds represented by the above formulas (6) and (7) one by one, or by copolymerizing two or more dihydroxy compounds having different structures. There may be. Furthermore, if necessary, it may be copolymerized with a dihydroxy compound or bisphenol having another structure.

  When the polycarbonate resin of the present invention is copolymerized with another dihydroxy compound or bisphenol, the ratio is preferably 60 mol% or less, and more preferably 50 mol% or less.

  Moreover, the glass transition temperature of the polycarbonate resin in this invention is 155 degrees C or less. Moreover, it is preferable that this glass transition temperature is 105 degreeC or more and 150 degrees C or less. If the glass transition temperature is higher than 155 ° C., solvent cracks are likely to occur. On the other hand, when the temperature is lower than 105 ° C., a phenomenon in which the toner adheres to the surface of the electrophotographic photosensitive member (hereinafter referred to as toner fusion) tends to occur when it is repeatedly used.

  It is preferable that the polystyrene conversion weight average molecular weight of the polycarbonate resin used for this invention is 20,000-200,000, More preferably, it is 25,000-100,000. If the weight average molecular weight in terms of polystyrene is less than 20,000, scratches and solvent cracks are likely to occur, and if it exceeds 200,000, the viscosity of the coating solution will increase, and defects such as unevenness and bubbles during coating are likely to occur. Become.

  Further, in the polycarbonate resin of the present invention, the oxygen atom content contained in the main chain is preferably 25% by mass or less, and more preferably 22% by mass or less from the viewpoint of adhesion to the toner.

<Polycarbonate resin of the present invention>
Below, the manufacturing method of the polycarbonate resin of this invention is described. For the polycarbonate resin of the present invention, a known melt polycondensation method in which a dihydroxy compound and a carbonic acid diester are reacted in the presence of a basic compound catalyst and / or a transesterification catalyst is suitably used.

  Examples of the carbonic acid diester used in the present invention include the following compounds.

Diphenyl carbonate Ditolyl carbonate Bis (chlorophenyl) carbonate m-cresyl carbonate Dimethyl carbonate Diethyl carbonate Dibutyl carbonate Dicyclohexyl carbonate

  Of these, diphenyl carbonate is particularly preferred. Diphenyl carbonate is preferably used in a ratio of 0.97 mol or more and 1.10 mol or less, and more preferably in a ratio of 0.98 mol or more and 1.05 mol or less with respect to 1 mol of the total of dihydroxy compounds. preferable.

  Examples of the basic compound catalyst include alkali metal compounds and / or alkalinity metal compounds, nitrogen-containing compounds, and the like.

  As such a compound, an organic acid salt such as an alkali metal or alkaline earth metal compound, an inorganic salt, an oxide, a hydroxide, a hydride, or an alkoxide is used. Moreover, as a nitrogen-containing compound, quaternary ammonium hydroxide or those salts, or amines are used preferably, These compounds may be used individually or in combination.

  Specific examples of the alkali metal compound include the following compounds.

Hydroxides (sodium hydroxide, potassium hydroxide, cesium hydroxide, lithium hydroxide, etc.)
Hydrocarbons (sodium bicarbonate, sodium carbonate, potassium carbonate, cesium carbonate, lithium carbonate, etc.)
Acetic acid (sodium acetate, potassium acetate, cesium acetate, lithium acetate, etc.)
Stearic acids (sodium stearate, potassium stearate, cesium stearate, lithium stearate, etc.)
Borides (sodium borohydride, sodium phenyl borohydride, etc.)
Benzoic acids (sodium benzoate, potassium benzoate, cesium benzoate, lithium benzoate, etc.)
Hydrogen phosphate (disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, etc.)
Disodium phenylphosphate Disodium salt of bisphenol A, 2 potassium salt, 2 cesium salt or 2 lithium salt Phenol sodium salt, potassium salt, cesium salt or lithium salt

  Specific examples of the alkaline earth metal compound include the following compounds.

Hydroxides (magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide)
Bicarbonate (magnesium bicarbonate, calcium bicarbonate, strontium bicarbonate, barium bicarbonate, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate)
Acetic acid oxide (magnesium acetate, calcium acetate, strontium acetate, barium acetate, etc.)
Stearic acid (magnesium stearate, calcium stearate, etc.)
Calcium benzoate Magnesium phenyl phosphate

  Specific examples of the nitrogen-containing compound include the following compounds.

Quaternary ammonium hydroxides having an alkyl group or an aryl group (tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylbenzylammonium hydroxide, etc.)
Tertiary amines (triethylamine, dimethylbenzylamine, triphenylamine, etc.)
Secondary amines (diethylamine, dibutylamine, etc.)
Primary amines (propylamine, butylamine, etc.)
Imidazoles (2-methylimidazole, 2-phenylimidazole, benzimidazole, etc.)
Base or basic salt (ammonia, tetramethylammonium borohydride, tetrabutylammonium borohydride, tetrabutylammonium tetraphenylborate, tetraphenylammonium tetraphenylborate, etc.)

  As the transesterification catalyst, zinc, tin, zirconium and lead salts are preferably used, and these may be used alone or in combination.

  Specific examples of the transesterification catalyst include the following compounds.

Zinc (zinc acetate, zinc benzoate, zinc 2-ethylhexanoate, etc.)
Tins (tin chloride (II), tin chloride (IV), tin acetate (II), tin acetate (IV), dibutyltin dilaurate, dibutyltin oxide, dibutyltin dimethoxide, etc.)
Zirconium (zirconium acetylacetonate, zirconium oxyacetate, zirconium tetrabutoxide, etc.)
Leads (lead acetate (II), lead acetate (IV), etc.)

These polymerization catalysts are used in a ratio of 1 × 10 ⁻⁹ to 1 × 10 ⁻³ mol, preferably 1 × 10 ⁻⁷ to 1 × 10 ⁻³ mol, relative to a total of 1 mol of the dihydroxy compound. It is done.

  The above-mentioned melt polycondensation method is a method in which melt polycondensation is performed using the above-mentioned raw materials and a polymerization catalyst while removing a by-product by a transesterification reaction under normal pressure or reduced pressure. The reaction is generally carried out in a multistage process of two or more stages.

  Specifically, the first stage reaction is performed at a temperature of 120 to 260 ° C., preferably 180 to 240 ° C. for 0.1 to 5 hours, preferably 0.5 to 3 hours. Next, the reaction temperature is raised while raising the degree of vacuum of the reaction system to carry out the reaction between the dihydroxy compound and the carbonic acid diester, and finally the polycondensation reaction is carried out at a temperature of 200 to 350 ° C. under a reduced pressure of 1 mmHg or less. The total reaction time (residence time) is preferably 1 to 10 hours. Such a reaction may be carried out continuously or batchwise. The reaction apparatus used for carrying out these reactions is equipped with paddle blades, lattice blades, glasses blades, etc. even with vertical types equipped with vertical stirring blades, Max blend stirring blades, helical ribbon stirring blades, etc. It may be a horizontal type or an extruder type equipped with a screw. In addition, it is preferable to use a reaction apparatus in which these are appropriately combined in consideration of the viscosity of the polymer.

  After completion of the polymerization reaction, the polycarbonate resin of the present invention removes or deactivates the catalyst in order to maintain thermal stability and hydrolysis stability. In general, a method of deactivating a catalyst by adding a known acidic substance is preferably performed. Specific examples of these substances include the following compounds.

Aromatic sulfonic acids (p-toluenesulfonic acid, etc.)
Aromatic sulfonate esters (butyl p-toluenesulfonate, hexyl p-toluenesulfonate, etc.)
Aromatic sulfonates such as tetrabutylphosphonium dodecylbenzenesulfonate
Organic halides (stearic acid chloride, benzoyl chloride, p-toluenesulfonic acid chloride, etc.)
Alkyl sulfate (dimethyl sulfate, etc.)
Organic halides (benzyl chloride, etc.)

  After deactivation of the catalyst, a step of devolatilizing and removing the low boiling point compound in the polymer at a pressure of 0.1 to 1 mmHg and a temperature of 200 to 350 ° C may be provided. In this step, a horizontal apparatus equipped with a stirring blade having excellent surface renewability such as a paddle blade, a lattice blade, or a glasses blade, or a thin film evaporator is preferably used.

  Next, the configuration of the electrophotographic photoreceptor according to the present invention will be described.

  The electrophotographic photoreceptor according to the present invention may have a structure of a single-layer type photosensitive layer containing a charge generation material and a charge transport material in a single layer as a photosensitive layer. The electrophotographic photosensitive member according to the present invention has a structure of a functionally separated type (laminated type) photosensitive layer that is functionally separated into a charge transport layer containing a charge transport material and a charge generation layer containing a charge generation material. Also good. The electrophotographic photoreceptor according to the present invention is preferably a function separation type (lamination type) in terms of electrophotographic characteristics, and more preferably a function separation type (lamination type) in which a charge generation layer and a charge transport layer are laminated in this order from the support side. . Hereinafter, the expression “separated type (laminated type)” refers to a layer in which a charge generation layer and a charge transport layer are laminated in this order from the support side.

  The surface layer of the electrophotographic photosensitive member according to the present invention has the above-described polycarbonate resin according to the present invention. The surface layer may be various layers, and examples thereof include a charge transport layer having a charge transport material, a charge generation layer having a charge generation material, and a protective layer.

  As the support used in the electrophotographic photoreceptor according to 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 molded into a drum or a sheet may be used. Moreover, what laminated | stacked metal foil, such as aluminum and copper, on the plastic film may be used. Furthermore, what vapor-deposited aluminum, indium oxide, tin oxide, etc. on the plastic film may be used.

  The surface of the support may be subjected to a cutting process, a roughening process (such as a honing process or a blasting process), an alumite process, or the like for the purpose of preventing interference fringes due to scattering of laser light or the like. Alternatively, chemical treatment may be performed with a solution obtained by dissolving a metal salt compound or a fluorine compound metal salt in an acidic aqueous solution mainly composed of alkali phosphate, phosphoric acid, or tannic acid.

  The honing process includes a dry honing process and a wet honing process. The wet honing treatment is a method in which a powdery abrasive is suspended in a liquid such as water and sprayed onto the surface of the support at a high speed to roughen the surface of the support. Thereby, the surface roughness can be controlled by spraying pressure, speed, amount of abrasive, type, shape, size, hardness, specific gravity, suspension temperature and the like. The dry honing process is a method in which the surface of the support is roughened by spraying an abrasive on the surface of the support with air at a high speed. Thereby, the surface roughness can be controlled similarly to the wet honing process. As an abrasive | polishing agent used for a honing process, particles, such as a silicon carbide, an alumina, iron, a glass bead, are mentioned.

  On the support, a conductive layer may be provided for the purpose of preventing interference fringes due to scattering of laser light or the like, or covering a scratch 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 a suitable solvent and coated on a support or a conductive layer to form an intermediate layer.

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

  In the case of the function separation type (laminated type) photosensitive layer, a charge generation layer is formed on the above-mentioned support, conductive layer, or intermediate layer.

  The charge generation layer is composed of a homogenizer, ultrasonic dispersion, ball mill, vibration ball mill, sand mill, attritor, roll mill, liquid collision type high speed disperser, etc. Disperse well with this method. Thereafter, this dispersion is applied and dried.

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

  As the charge generation material, those generally known can be used. Examples include pigments such as selenium-tellurium, pyrylium, metal phthalocyanine, metal-free phthalocyanine, anthanthrone, dibenzpyrenequinone, trisazo, cyanine, disazo, monoazo, indigo, quinacudrine.

  These pigments can be obtained by using a homogenizer, ultrasonic dispersion, ball mill, vibration mill, sand mill attritor, roll mill, liquid collision type high speed disperser, etc. together with binder resin and solvent having a mass of 0.3 to 4 times. A dispersed dispersion is obtained. In the case of a function-separated type (laminated type) photosensitive layer, the dispersion is applied on a support, a conductive layer, or an intermediate layer, and dried to obtain a charge generation layer.

  In the case of a function separation type (laminated type) photosensitive layer, a charge transport layer is formed on the charge generation layer.

  The charge transport layer is prepared by dissolving the charge transport material and the binder resin of the present invention in a solvent to form a coating solution, coating the coating solution on the charge generation layer, and drying the coating solution.

  It is known that a solvent crack is particularly likely to occur in a structure in which a charge transport material having a relatively low molecular weight, specifically, a charge transport material having a molecular weight of less than 1000 and a binder resin are mixed. By using the resin of the present invention, excellent solvent crack resistance can be exhibited even in the above-described configuration.

  The ratio of the charge transport material to the binder resin (charge transport material / binder resin) in the coating solution is preferably 10/100 or more and 200/100 or less in terms of mass ratio. Further, from the viewpoint of the compatibility between the charge transport material and the binder resin, the adhesion to the toner, or the effect on the solvent crack, 50/100 or more and 90/100 or less are more preferable.

  As the binder resin, the above polycarbonate resin may be used alone, or two or more kinds may be mixed and used. Furthermore, you may mix with resin other than the polycarbonate resin in this invention as needed. Examples of the binder resin to be mixed include polycarbonate resins other than those described above, polyarylate resins, polyester resins, polystyrene resins, polymethacrylate resins, and polyacrylate resins.

  When mixed with a resin other than the resin in the present invention, the mixing ratio is preferably 5/95 or more and 95/5 or less, and more preferably 10/90 or more and 90/10 or less in terms of mass ratio. In addition, the glass transition temperature and oxygen atom content of resin other than resin in this invention are not specifically limited.

  Moreover, you may add antioxidant, a heat stabilizer, a ultraviolet absorber, and a plasticizer in a charge transport layer as needed.

  Furthermore, you may use a lubricant and microparticles as needed. Examples of the lubricant or fine particles include the following substances.

Resin fine particles (polytetrafluoroethylene fine particles, polystyrene fine particles, etc.)
Metal oxide fine particles (silica fine particles, alumina fine particles, tin oxide fine particles, etc.)
Fine particles obtained by surface treatment of these fine particles Solid lubricant (such as zinc stearate)
Silicone substituted with alkyl groups Aliphatic oil varnish with alkyl fluoride groups

  The thickness of the charge transport layer is preferably 5 to 40 μm, and preferably 8 to 30 μm.

  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. A single solvent or a plurality of solvents may be used.

  Examples of the coating method include generally known methods such as dip coating, spray coating, and bar coating.

<Process cartridge and electrophotographic apparatus according to the present invention>
Next, an electrophotographic apparatus having a process cartridge having an electrophotographic photosensitive member according to the present invention will be described.

  FIG. 1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus having an electrophotographic photosensitive member according to the present invention. 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 a direction indicated by an arrow at a predetermined peripheral speed. In the rotation process, the electrophotographic photosensitive member 1 is uniformly charged at a predetermined positive or negative potential on its peripheral surface by the primary charging unit 3. Subsequently, the exposure light 4 from exposure means (not shown), such as slit exposure and laser beam scanning exposure, is received. In this way, electrostatic latent images are sequentially formed on the peripheral surface of the electrophotographic photoreceptor 1.

  The formed electrostatic latent image is then developed with toner by the developing means 5. Thereafter, the developed toner developed image is fed from a paper feed unit (not shown) between the electrophotographic photosensitive member 1 and the transfer means 6 in synchronization with the rotation of the electrophotographic photosensitive member 1. 7 is sequentially transferred by the transfer means 6.

  The transfer material 7 that has received the image transfer is separated from the surface of the electrophotographic photosensitive member, introduced into the image fixing means 8, and subjected to image fixing, thereby being printed out as an image formed product (print or copy).

  The surface of the electrophotographic photosensitive member 1 after the image transfer is cleaned by removing the transfer residual toner by the cleaning unit 9 and further subjected to charge removal processing by the pre-exposure light 10 from the pre-exposure unit (not shown). After that, it is repeatedly used for image formation. When the primary charging unit 3 is a contact charging unit using a charging roller or the like as shown in FIG. 1, pre-exposure is not always necessary.

  In the present invention, as a process cartridge, a plurality of components such as the above-described electrophotographic photosensitive member 1, primary charging means 3, developing means 5 and cleaning means 9 are integrally combined as a process cartridge. May be. The process cartridge may be configured to be detachable from a main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. For example, at least one of the primary charging unit 3, the developing unit 5 and the cleaning unit 9 is integrally supported with the electrophotographic photosensitive member 1 to form a cartridge, which can be attached to and detached from the apparatus main body using a guide unit 12 such as a rail of the apparatus main body. Process cartridge 11.

  Further, when the electrophotographic apparatus is a copying machine or a printer, the exposure light 4 may be reflected light or transmitted light from a document. Alternatively, the light may be emitted by reading a document with a sensor, converting the signal into a signal, scanning a laser beam performed according to the signal, driving an LED array, driving a liquid crystal shutter array, and the like.

  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 Hereinafter, although this invention is demonstrated in detail according to an Example, this invention is not limited to these. In the examples, “part” means “part by mass”. The physical properties in Table 1 are measured by the following methods.

  1) Glass transition temperature (Tg): Using a differential thermal scanning calorimeter (DSC) SSC / 5200 manufactured by Seiko Instruments Inc., from 40 ° C. to 200 ° C. at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere. The temperature rose. Then, it cooled once and it heated up again from 40 degreeC to 200 degreeC with the temperature increase rate of 10 degree-C / min, and measured by making 2nd measured value into glass transition temperature.

  2) Weight average molecular weight (Mw) in terms of polystyrene: A calibration curve was prepared using standard polystyrene having a known molecular weight (molecular weight distribution = 1) using GPC and chloroform as a developing solvent. Based on this calibration curve, it was calculated from the retention time of GPC.

3) Oxygen atom content It calculated from the molecular weight and molar ratio of the structural unit contained in resin.

Example 1
<Manufacture of polycarbonate resin (PC-1)>
The following components were placed in a 300 ml four-necked flask equipped with a stirrer and a distillation apparatus, heated to 180 ° C. under a nitrogen atmosphere of 760 mmHg, and stirred for 30 minutes.

4,3.9 g of 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene
(Hereinafter referred to as Compound A) (0.100 mol)
Pentacyclopentadecanedimethanol 26.2g
(Hereinafter referred to as Compound B) (0.100 mol)
(Hereinafter, these compounds A and B are collectively referred to as starting materials.)
43.7g of diphenyl carbonate
(0.204 mol)
Sodium bicarbonate 2.5 × 10 ⁻³ g
(3 × 10 ⁻⁵ mol)

  Thereafter, the degree of vacuum was adjusted to 150 mmHg, and at the same time, the temperature was raised to 200 ° C. at a rate of 60 ° C./hour, and held at that temperature for 20 minutes to conduct a transesterification reaction. Furthermore, the temperature was raised to 225 ° C. at a rate of 75 ° C./hour, and 10 minutes after the completion of the temperature raising, the degree of vacuum was reduced to 1 mmHg or less over 1 hour while maintaining the temperature. Thereafter, the temperature was raised to 235 ° C. at a rate of 60 ° C./hour, and the reaction was further performed with stirring for 1.5 hours. After completion of the reaction, nitrogen was blown into the reactor to return to normal pressure, and the produced polycarbonate resin (PC-1) was taken out. The physical property measurement results of the obtained polycarbonate resin (PC-1) are shown in Table 1.

<Manufacture of electrophotographic photoreceptor>
An aluminum cylinder having a diameter of 24 mm and a length of 246 mm was used as a support.

  Next, the following components were dispersed in a sand mill apparatus using glass beads having a diameter of 1 mm for 2 hours to prepare a conductive layer coating solution.

Titanium oxide particles coated with tin oxide containing 10% by mass of antimony oxide 50 parts Resol type phenol resin 25 parts Methoxypropanol 30 parts Methanol 30 parts Silicone oil 0.002 parts (Polydimethylsiloxane polyoxyalkylene copolymer, weight average Molecular weight 3000)

  The conductive layer coating solution was dip-coated on a support and cured at 140 ° C. for 20 minutes to form a conductive layer having a thickness of 15 μm.

  Next, an intermediate layer coating solution was prepared by dissolving 5 parts of N-methoxymethylated 6 nylon in 95 parts of methanol.

  This intermediate layer coating solution was dip coated on a support and dried at 100 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.6 μm.

  Next, the following components were dispersed in a sand mill apparatus using glass beads having a diameter of 1 mm for 4 hours, and then 250 parts of ethyl acetate was added to prepare a charge generation layer coating solution.

10 parts of hydroxygallium phthalocyanine crystal (charge generating material) (7.5 °, 9.9 °, 12.5 °, 16.3 °, 18 of Bragg angle (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction) Crystal forms having strong peaks at .6 °, 25.1 ° and 28.3 °)
Compound having the structure represented by the following formula (8) 0.1 part Polyvinyl butyral resin 5 parts (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.)
250 parts of cyclohexanone

  This 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 0.2 μm.

  Next, the following components were dissolved in a mixed solvent of 45 parts of monochlorobenzene and 10 parts of dimethoxymethane to prepare a charge transport layer coating solution.

Charge transport material represented by the following formula (CT-1) 3.5 parts Charge transport material represented by the following formula (CT-2) 3.5 parts Polycarbonate resin (PC-1) 10 parts (as binder resin)

  This was applied onto the charge generation layer by a dip coating method and dried at 105 ° C. for 1 hour to form a charge transport layer having a thickness of 13 μm.

(Each evaluation method)
First, the liquid stability evaluation method of the coating liquid for charge transport layers of this invention is demonstrated.

  The liquid stability was evaluated by visually observing whether the coating liquid was gelled or whitened after it was left in a room temperature and humidity environment (23 ° C., 50% RH) for 1 month. did. In the evaluation, the case where gelation or whitening of the coating solution did not occur was evaluated as ◯, and the case where it occurred was evaluated as x.

  Next, a method for evaluating a solvent crack of the electrophotographic photosensitive member according to the present invention will be described.

  The evaluation device used was a cartridge in which a cartridge for LBP “Laser Jet 1012” manufactured by Hewlett-Packard was replaced with a charging roller for applying DC voltage. The evaluation was performed by mounting the produced electrophotographic photosensitive member on the above-described cartridge and leaving it in a 40 ° C. and 90% RH environment for one month, and then observing whether a crack occurred in the charging roller contact portion. went. In the judgment, A is a crack not generated, B is a slight crack, and C is a crack.

  Next, a method for evaluating scratches and potential fluctuations of the electrophotographic photosensitive member of the present invention will be described.

  As the evaluation apparatus, LBP “Laser Jet 1012” manufactured by Hewlett-Packard modified as described in (1) to (3) below was used.

(1) Primary charging: Contact charging system that applies only DC voltage (2) Charging roller: Charging roller for DC voltage application (3) Modification to adjust the charging potential and image exposure of the electrophotographic photosensitive member

  The evaluation was performed in a normal temperature and normal humidity environment (23 ° C., 50% RH).

  Evaluation of scratches by repeated use of the produced electrophotographic photosensitive member was performed by setting the initial dark part potential to be −550V and the bright part potential to be −150V. For evaluation of scratches on the electrophotographic photosensitive member, 3000 sheets of A4 size plain paper were output once for each image output, and the subsequent surface roughness (Rz) (μm) was measured. The surface roughness of the electrophotographic photosensitive member was measured using a surface roughness measuring instrument (Surfcoder SE-3400, Konishi Laboratory Co., Ltd.). Using this, evaluation (evaluation length: 8 mm) was performed in accordance with the ten-point average roughness (Rzjis) evaluation in JIS B 0601: 2001, and a position 120 mm from the upper end of the electrophotographic photosensitive member was measured.

  The evaluation of the fluctuation (ΔVl) of the bright part potential due to repeated use of the produced electrophotographic photosensitive member is performed by setting the initial dark part potential on the surface of the electrophotographic photosensitive member to be −550 V and the bright part potential to be −150 V. It was. The evaluation of the fluctuation of the bright part potential due to repeated use of the electrophotographic photosensitive member was performed by continuously outputting 2000 sheets of A4 size plain paper and measuring the surface potential before and after that. The surface potential of the electrophotographic photosensitive member was measured at the developing device position by exchanging the jig and the developing device fixed so that the potential measuring probe was positioned 130 mm from the upper end of the electrophotographic photosensitive member.

  Next, the toner adhesion evaluation method of the electrophotographic photosensitive member of the present invention will be described.

  As an evaluation sample, an aluminum sheet obtained by dip coating an electrophotographic photosensitive member was used. The produced electrophotographic photosensitive member was affixed to a flat surface and fixed in a state inclined at 45 °. The evaluation of toner adhesion was performed by dropping the toner on the surface of the photoconductor and observing the state of the toner adhering to the surface of the photoconductor. In the judgment, A with little toner adhesion was A, B with slightly toner adhesion, and C with much adhesion. The evaluation results are shown in Table 1.

(Example 2)
The same procedure as in Example 1 was carried out except that 19.6 g (0.100 mol) of tricyclo [5.2.1.02,6] decandimethanol was used in place of compound B in Example 1, and polycarbonate was used. Resin (PC-2) was obtained. The physical property measurement results of this polycarbonate resin are shown in Table 1.

  Furthermore, an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that (PC-2) was used as the binder resin. The evaluation results are shown in Table 1.

(Example 3)
In Example 1, the same procedure as in Example 1 was carried out except that 70.2 g of Compound A (0.160 mol) and 11.8 g of Compound B (0.0400 mol) were used as starting materials. Resin (PC-3) was obtained. The physical property measurement results of this polycarbonate resin are shown in Table 1.

  Further, an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that (PC-3) was used as the binder resin. The evaluation results are shown in Table 1.

Example 4
In Example 1, 26.3 g of compound A (0.0600 mol) and 36.7 g of compound B (0.140 mol) were used as starting materials. Otherwise by performing the same operations as in Example 1, a polycarbonate resin (PC-4) was obtained. The physical property measurement results of this polycarbonate resin are shown in Table 1.

  Furthermore, an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that (PC-4) was used as the binder resin. The evaluation results are shown in Table 1.

(Example 5)
In Example 1, 78.9 g of compound A (0.180 mol) and 3.9 g (0.0200 mol) of tricyclo [5.2.1.02,6] decandimethanol were used as starting materials. Otherwise by performing the same operations as in Example 1, a polycarbonate resin (PC-5) was obtained. The physical property measurement results of this polycarbonate resin are shown in Table 1.

(Example 6)
In Example 1, 61.4 g of compound A (0.140 mol) and 11.8 g (0.0600 mol) of tricyclo [5.2.1.02,6] decandimethanol were used as starting materials. Otherwise by performing the same operations as in Example 1, a polycarbonate resin (PC-6) was obtained. The physical property measurement results of this polycarbonate resin are shown in Table 1.

  Further, an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 2 except that (PC-6) was used as the binder resin. The evaluation results are shown in Table 1.

(Example 7)
In Example 1, 26.3 g of compound A (0.0600 mol) and tricyclo [5.2.1.02,6] decandimethanol 27.5 g (0.140 mol) were used as starting materials. Otherwise by performing the same operations as in Example 1, a polycarbonate resin (PC-7) was obtained. The physical property measurement results of this polycarbonate resin are shown in Table 1.

  Furthermore, an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that (PC-7) was used as the binder resin. The evaluation results are shown in Table 1.

(Example 8)
In Example 1, except that 14.4 g (0.100 mol) of cyclohexane-1,4-dimethanol was used instead of Compound B, the same operation as in Example 1 was carried out to obtain a polycarbonate resin (PC-8). Obtained. The physical property measurement results of this polycarbonate resin are shown in Table 1.

  Furthermore, an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that (PC-8) was used as the binder resin. The evaluation results are shown in Table 1.

Example 9
In Example 4, the same operation as in Example 1 was performed except that 20.2 g (0.140 mol) of cyclohexane-1,4-dimethanol was used in place of Compound B, and a polycarbonate resin (PC-9) was obtained. Obtained. The physical property measurement results of this polycarbonate resin are shown in Table 1.

  Furthermore, an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that (PC-9) was used as the binder resin. The evaluation results are shown in Table 1.

(Example 10)
In Example 1, 8.8 g of compound A (0.0200 mol) and tricyclo [5.2.1.02,6] decandimethanol 35.4 g (0.180 mol) were used as starting materials. Otherwise by performing the same operations as in Example 1, a polycarbonate resin (PC-10) was obtained. The physical property measurement results of this polycarbonate resin are shown in Table 1.

  Further, an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that (PC-10) was used as the binder resin. The evaluation results are shown in Table 1.

(Example 11)
In Example 1, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the following components were used as the binder resin. The evaluation results are shown in Table 1.

PC-1 7 parts Polycarbonate resin having a repeating unit represented by the following formula 3 parts (PC-Z, Mw: 55000)

(Example 12)
In Example 1, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that 9 parts of PC-2 and 1 part of PC-Z (Mw: 55000) were used as the binder resin. . The evaluation results are shown in Table 1.

(Example 13)
In Example 1, an electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that 5.5 parts of CT-1 was used as the charge transport material. The evaluation results are shown in Table 1.

(Example 14)
In Example 1, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that 1.5 parts of CT-1 was used as the charge transport material. The evaluation results are shown in Table 1.

(Example 15)
In Example 1, an electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that 6.5 parts of CT-1 was used as the charge transport material. The evaluation results are shown in Table 1.

(Example 16)
In Example 1, an electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that 1 part of CT-1 was used as the charge transport material. The evaluation results are shown in Table 1.

(Comparative Example 1)
In Example 1, a polycarbonate resin (PC-11) was obtained in the same manner as in Example 1 except that only 87.7 g of Compound A (0.200 mol) was used as a starting material. The physical property measurement results of this polycarbonate resin are shown in Table 1.

  Further, an electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that PC-11 was used as the binder resin and dichloromethane was used in place of dimethoxymethane as the solvent used in the charge transport layer coating solution. . The evaluation results are shown in Table 1.

(Comparative Example 2)
In Example 1, except that 14.6 g (0.100 mol) of 1,4,3,6-sorbide was used instead of Compound B, the same operation as in Example 1 was carried out to obtain a polycarbonate resin (PC-12). Got. The physical property measurement results of this polycarbonate resin are shown in Table 1.

  Furthermore, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that PC-12 was used as the binder resin. The evaluation results are shown in Table 1.

(Comparative Example 3)
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that polycarbonate resin (PC-13) having a repeating unit represented by the following formula was used as the binder resin of Example 1. The evaluation results are shown in Table 1.

(Comparative Example 4)
In Example 1, a polycarbonate resin (PC-14) was obtained in the same manner as in Example 1 except that the following components were used as starting materials. The physical property measurement results of this polycarbonate resin are shown in Table 1.

9,9-bis (4-hydroxy-3-methylphenyl) fluorene 22.7 g
(0.0600 mol)
Cyclohexane-1,4-dimethanol 20.2g
(0.140 mol)

  Furthermore, an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that PC-14 was used as the binder resin. The evaluation results are shown in Table 1.

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

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Axis 3 Primary charging means 4 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 Guide means

Claims (9)

An electrophotographic photoreceptor containing a polycarbonate resin in the surface layer,
The polycarbonate resin has the following formula (1)

(In the formula (1), each R ₁ independently represents an alkylene group having 2 to 10 carbon atoms, a cycloalkylene group having 6 to 20 carbon atoms, or an arylene group having 6 to 20 carbon atoms, R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.
A repeating unit represented by the following formula (2):

(In formula (2), X represents a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 5 to 20 carbon atoms, or the following formula (3):

The connection structure shown by is shown. )
And a glass transition temperature of 155 ° C. or lower.   The electrophotographic photosensitive member according to claim 1, wherein a ratio of the repeating unit represented by the formula (1) is 30 mol% or more and 90 mol% or less. The repeating unit represented by the formula (2) is represented by the following formula (4).

Or the following formula (5)

The electrophotographic photosensitive member according to claim 1, wherein   4. The electrophotographic photosensitive member according to claim 1, wherein a ratio of the repeating unit represented by the formula (1) is 30 mol% or more and 70 mol% or less.   The electrophotographic photosensitive member according to claim 1, wherein the polycarbonate resin has a glass transition temperature of 150 ° C. or lower.   The electrophotographic photosensitive member according to claim 1, wherein the surface layer contains a charge transport material.   The electrophotographic photosensitive member according to claim 6, wherein a ratio of the charge transporting material to the binder resin is 50/100 or more and 90/100 or less in terms of mass ratio. An electrophotographic photosensitive member according to any one of claims 1 to 7,
At least one means selected from the group consisting of charging means, developing means and cleaning means;
A process cartridge characterized by being integrally supported and detachable from the main body of the electrophotographic apparatus.   An electrophotographic apparatus comprising: the electrophotographic photosensitive member according to claim 1; and a charging unit, an exposure unit, a developing unit, and a transfer unit.