JP4095509B2 - Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member having a curable surface layer, and in addition to the curable charge transporting compound, the surface layer contains an electrophotographic compound having a charge transporting compound having at least one hydroxyl group. The present invention relates to a photoreceptor. The present invention also relates to an electrophotographic apparatus having the above electrophotographic photosensitive member, an apparatus unit, and a facsimile.

  In recent years, organic photoconductive substances having advantages such as pollution-free and high productivity have been widely used as materials used for electrophotographic photoreceptors. These electrophotographic photoreceptors are often used as function-separated photoreceptors in which a charge generation layer and a charge transport layer are laminated in order to satisfy both electrical and mechanical properties.

  On the other hand, as a matter of course, the electrophotographic photosensitive member is required to have sensitivity, electrical characteristics, and optical characteristics according to the applied electrophotographic process. In particular, since various electric and mechanical external forces such as charging, exposure, toner development, transfer to paper and cleaning are directly applied to the surface layer of the photoreceptor to be used repeatedly, durability against them is required. .

Specifically, due to degradation caused by active substances such as ozone, NO _x , and nitric acid generated during charging, the sensitivity and potential may decrease, and the residual potential may increase. However, durability against these is required.

As a means for solving these problems, for example, a photoreceptor containing a cured product of a charge transporting compound having a chain polymerizable functional group in the same molecule in the outermost surface layer is known (for example, Patent Documents). 1). By using such a curable film having charge transportability, it is possible to achieve both excellent mechanical strength and charge transport ability. However, since the curable film having the above-described charge transporting property has a three-dimensional cross-linked structure in a very short time, the charge transporting group is not necessarily cured in an optimal arrangement, and has good electrophotographic characteristics. Although it has mechanical strength, it still has not reached its full performance.
JP 2000-147813 A

  An object of the present invention is to provide an electrophotographic photosensitive member in which the mechanical strength and electrophotographic characteristics of a curable film having a charge transport property are further expressed, and a process cartridge and an electrophotographic apparatus having the same.

As a result of intensive studies, the present inventors have found that in an electrophotographic photosensitive member having a conductive support and a photosensitive layer provided on the conductive support, the photosensitive layer is the same as that of the electrophotographic photosensitive member. Forming a surface, composed of a single layer, or composed of a plurality of stacked layers, the photosensitive layer composed of a single layer, or of the photosensitive layer composed of a plurality of layers The layer that forms the surface of the electrophotographic photoreceptor is a mixture containing at least a first charge transporting compound having an acryloyloxy group or a methacryloyloxy group and a second charge transporting compound having a hydroxyl group. The cured product obtained by carrying out at least one of or both of polymerization and crosslinking of the first charge transporting compound, and the mixture contains the second charge transporting compound as the first charge transporting compound. transport An electrophotographic photosensitive member which is a mixture containing 0.01 to 5.0 wt% relative to the compound has been found to be intended to solve the problems described above.

  This is because the second charge transporting compound is excellent in affinity with the first charge transporting compound which is a curable monomer having an acryloyloxy group or a methacryloyloxy group. The intermolecular distance between the charge transport compound and the three-dimensional crosslinked structure can be efficiently incorporated after curing, and an ideal charge transport layer in which the charge transport compound is condensed at an extremely high density can be formed. This is thought to be possible. As a result, it is considered that the present invention can provide an electrophotographic photoreceptor excellent in mechanical strength and electrical characteristics.

  According to the electrophotographic photosensitive member, the process cartridge, and the electrophotographic apparatus of the present invention, the photosensitive layer of the electrophotographic photosensitive member having the curable outermost surface layer contains a certain amount of the charge transporting compound having at least one hydroxyl group. By doing so, an electrophotographic photoreceptor having excellent mechanical strength and electrical characteristics can be produced, and high-quality images can be continuously formed.

  In the present invention, when the mixture contains the second charge transporting compound in an amount of 0.05 to 2.0% by mass with respect to the first charge transporting compound, the first and second charge transporting properties are included. This is even more effective in fully exhibiting the electrical characteristics inherent to the compound.

  In the present invention, the photosensitive layer composed of the single layer or the layer forming the surface of the electrophotographic photosensitive member is formed by curing the mixture with an electron beam. It is more effective in suppressing the influence of the polymerization initiator in the layer on the electrophotographic characteristics, suppressing the influence of the additive on the curing inhibition during production, and increasing the productivity.

  Details of the present invention will be described below.

  The electrophotographic photosensitive member of the present invention has a conductive support and a photosensitive layer provided on the conductive support.

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

  The photosensitive layer is provided on the conductive support and forms the surface of the electrophotographic photosensitive member when exposed. The photosensitive layer may be provided directly on the surface of the conductive support, or the conductive support through an appropriate other layer for improving the electrical characteristics and mechanical characteristics of the electrophotographic photosensitive member. It may be provided above.

  The photosensitive layer forms an electrostatic latent image by exposure. Such a photosensitive layer can be constituted by a layer having a function of generating charges by exposure and a function of transporting the generated charges. Such a photosensitive layer is composed of a single layer containing a charge generating substance and a charge transporting substance, or a plurality of layers in which a charge generating function layer and a charge transporting function layer are stacked. Can do. In the present invention, any of these photosensitive layers can be applied.

The photosensitive layer composed of a single layer, or the layer forming the surface of the electrophotographic photoreceptor among the photosensitive layers composed of a plurality of layers has at least an acryloyloxy group or a methacryloyloxy group. It is formed by a cured product of a mixture containing one charge transporting compound and a second charge transporting compound having one or more hydroxyl groups. The first charge transporting compound used may be one kind or two or more kinds. Similarly, the second charge transporting compound used may be one kind or two or more kinds.

  The first charge transporting compound is a compound in which at least one acryloyloxy group or methacryloyloxy group is chemically bonded to the charge transporting group as a functional group. When the first charge transporting compound has a plurality of acryloyloxy groups or methacryloyloxy groups, all of the acryloyloxy groups or methacryloyloxy groups may be the same or different. The first charge transporting compound is preferably a compound represented by the following general formula (1). The first charge transporting compound has a plurality of acryloyloxy groups or methacryloyloxy groups, that is, a + b × d is 2 or more in the following general formula (1) to form the surface of the electrophotographic photoreceptor. In the layer to be used, it is more preferable to achieve both excellent mechanical strength and electrical characteristics.

  The second charge transporting compound is a compound in which at least one hydroxyl group is chemically bonded to the charge transporting group as a functional group. The second charge transporting compound is preferably a compound represented by the following general formula (2).

In the first and second charge transporting compounds, “may be the same or different” means that when there are a plurality of substituents arbitrarily selected from a plurality of types, these substituents are of the same type. It indicates that it may be a substituent or a different kind of substituent. More specifically, in the general formula (2), “when a is 2 or more, P ³ may be the same or different” means different functional groups (acryloyloxy group, methacryloyloxy group, alkyl group). , Aryl group, hydrogen atom, halogen atom or hydroxyl group) as P ¹¹ , P ¹² , P ¹³ , P ¹⁴ , P ¹⁵ ... P ¹ⁿ as long as it has at least one hydroxyl group. Well, for example, when a = 3, all three functional groups P ³ directly bonded to the charge transporting group A are the same, but two are the same but different (for example, P ¹¹ , P ¹¹ and P ¹² Toka) also differ from three, respectively and also (for example, P ¹² and P ¹⁵ and P ¹⁷ Toka) is intended to mean that may be ( "if d is 2 or P ⁴ may be the same or different "When b is 2 or more, Z is the same or different. “It ’s okay” means the same thing).

The charge transporting group in the first and second charge transporting compounds is not particularly limited as long as it is a functional group exhibiting charge transporting properties. As such a charge transporting group, for example, a hole transporting group described in JP-A No. 2000-147813 can be used. Such charge transporting groups include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, diarylamines when represented as hydrogenation compounds in which the bonding site to P ¹ or Z in the above general formula is replaced with a hydrogen atom Derivatives, triarylamine derivatives such as triphenylamine, 9- (p-diethylaminostyryl) anthracene, 1,1-bis- (4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline, phenylhydrazones, thiazole Derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, thiophene derivatives, N-phenylcarbazole derivatives, optionally substituted naphthalene, anthracene, phenanthrene, pyreth , Condensed ring hydrocarbons such as fluorene, fluoranthene, azulene, indene, perylene, chrysene, coronene, or optionally substituted benzofuran, indole, carbazole, benzcarbazole, acridine, phenothiazine, quinoline, etc. And a compound that becomes a compound in which a plurality of these are combined.

In addition, the organic group in the general formulas (1) and (2) is appropriately connected to a charge transporting group and an acryloyloxy group, a methacryloyloxy group, or a hydroxyl group so as not to impair the function of each substituent. The organic group is not particularly limited as long as it is an organic group. As such an organic group, for example, organic residues described in JP-A No. 2000-147813 can be used. Examples of such an organic group include an alkylene group which may have a substituent, an arylene group which may have a substituent, CR ²¹ = CR ²² (R ²¹ and R ²² are an alkyl group, an aryl group, or a hydrogen atom) R ²¹ and R ²² may be the same or different), C═O, S═O, SO ₂ , an oxygen atom or a sulfur atom, or an arbitrary combination of two or more. A substituent etc. are mentioned.

  The mixture contains 0.01 to 5.0% by mass of the second charge transporting compound with respect to the first charge transporting compound. When the content of the second charge transporting compound in the mixture is smaller than the above range, a photosensitive layer that can sufficiently exhibit the original electrical characteristics may not be obtained, and when the content is larger than the above range. Since the plastic action increases, the mechanical strength of the layer forming the surface of the electrophotographic photosensitive member tends to decrease. The electrical property and mechanical strength of the photosensitive layer are such that the content of the second charge transporting compound relative to the first charge transporting compound in the mixture is 0.05 to 2.0% by mass. It is more preferable when forming a photosensitive layer having excellent resistance.

  The cured product is obtained by performing at least one of polymerization and crosslinking of the first charge transporting compound in the mixture or both. In the polymerization and crosslinking, not only the first charge transporting compound but also the second charge transporting compound in the mixture may be polymerized or crosslinked. The first charge transporting compound can be polymerized or crosslinked by heat, light and radiation, and is preferably polymerized by radiation.

  The greatest advantage of polymerization by radiation is that a polymerization initiator is not required, and the influence on the electrophotographic characteristics due to this can be eliminated. In addition, the productivity is high because it is a short and efficient polymerization reaction. In addition, because of its good radiation transparency, the effect of curing inhibition due to the presence of a shielding substance such as a thick film or an additive in the film is very small. However, depending on the type of central skeleton having a charge transporting property such as the electron transporting group or a functional group in which the organic group is bonded to the electron transporting group, the polymerization reaction may not easily proceed. It is possible to add a polymerization initiator within a range that does not affect the photographic characteristics.

  The radiation is preferably an electron beam or a γ ray. In the case of electron beam irradiation, any type of accelerator such as a scanning type, an electro curtain type, a broad beam type, a pulse type, and a laminar type can be used. When irradiating an electron beam, in the electrophotographic photosensitive member of the present invention, the irradiation conditions are very important in order to develop electrical characteristics and durability.

  In the present invention, the acceleration voltage is preferably 250 kV or less, and optimally 150 kV or less. The irradiation dose is preferably in the range of 0.5 Mrad to 100 Mrad, more preferably in the range of 1 Mrad to 20 Mrad. When the accelerating voltage exceeds the above, the electron beam irradiation damage tends to increase on the characteristics of the photoreceptor. In addition, when the irradiation dose is less than the above range, the curing tends to be insufficient, and when the irradiation dose is large, the photoreceptor characteristics are likely to be deteriorated due to the deterioration of the photoreceptor, so care should be taken.

The photosensitive layer composed of a single layer, or the layer forming the surface of the electrophotographic photosensitive member, is a solution containing the first and second charge transporting compounds, the conductive support or the like. It can be produced by applying a polymerization reaction or a cross-linking reaction after application to an object to form a layer. Alternatively, the layer forming the surface of the electrophotographic photosensitive member is obtained by previously reacting a solution containing the first and second charge transporting compounds to obtain a cured product, and then dispersing the cured product in the solvent again. Alternatively, it can be formed using a dissolved paint or the like. In this case, the photosensitive layer composed of a single layer, or the layer that forms the surface of the electrophotographic photosensitive member, is applied, for example, with a paint containing the cured product to the object on which the layer is to be formed. Formed by drying. As the solvent of the solution, a solvent selected from known solvents capable of dissolving at least the first charge transporting compound or a mixture thereof can be used.

  In the present invention, as a method of applying the coating material such as the solution, for example, a dip coating method, a spray coating method, a curtain coating method, and a spin coating method are known. The method is preferred. In the present invention, vapor deposition, plasma, and other known film forming methods can be appropriately selected for forming the aforementioned layers.

  In the present invention, a charge transporting monomer (first charge transporting compound) which is one of the constituent elements of the photosensitive layer composed of the single layer or the layer forming the surface of the electrophotographic photoreceptor. An acryloyloxy group or a methacryloyloxy group is selected as the chain polymerizable functional group. The reason is that these chain-polymerizable functional groups are particularly excellent in reactivity and polymerize and crosslink in a very short time, so that productivity is high and mechanical strength after curing is also high.

  However, when the first charge transporting compound is used, although the mechanical strength is excellent, the original electrical characteristics may not be obtained. This is considered because the chain polymerizable functional group is polymerized and crosslinked in a very short time, and the charge transporting group is not necessarily cured into a three-dimensional crosslinked structure in an ideal arrangement. ing.

  However, the layer forming the surface of the electrophotographic photosensitive member described above is composed of a charge transporting compound (second charge transporting compound) having one or more hydroxyl groups in the same molecule and the first charge transporting compound. It is possible to improve electrical characteristics without impairing mechanical strength by forming a cured product of a mixture containing an appropriate amount of.

  The reason is not yet clear, but by adding a charge transporting compound having at least one hydroxyl group having high affinity with acryloyloxy group and methacryloyloxy group in the same molecule and curing it, the tertiary A charge transporting compound having a hydroxyl group is incorporated into the original network cross-linking structure, and the charge transporting group can form an ideal charge transporting layer. It is assumed that the characteristics can be improved.

  In the present invention, in addition to the surface layer of the electrophotographic photoreceptor, a layer not exposed on the surface may be formed of a cured product of the mixture.

  Below, the manufacturing method of the electrophotographic photoreceptor of the present invention is specifically shown.

  In the present invention, an undercoat layer having a barrier function and an adhesive function can be provided on the conductive support. The undercoat layer improves the adhesion of the photosensitive layer, improves the coating properties, protects the conductive support, covers defects on the surface of the conductive support, improves the charge injection from the conductive support, It is formed to protect against mechanical destruction.

  Materials for the undercoat layer include polyvinyl alcohol, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, ethylene-acrylic acid copolymer, casein, polyamide, N-methoxymethylated 6 nylon, copolymer nylon, glue and gelatin Etc. are known. One or more of these known materials are used as the material for the undercoat layer.

  The material of the undercoat layer is dissolved in a solvent suitable for each and coated on the conductive support. Then, the undercoat layer is formed by an appropriate treatment such as drying. The film thickness at that time is preferably 0.1 to 2 μm.

  When the electrophotographic photoreceptor in the present invention is a function separation type photoreceptor, a charge generation layer and a charge transport layer are laminated. The charge generation material used for the charge generation layer is not particularly limited as long as it is a material that generates charge upon exposure. Such charge generating materials include selenium-tellurium, pyrylium, thiapyrylium dyes, and various central metals and crystal systems, specifically, phthalocyanines having crystal types such as α, β, γ, ε, and X types. Examples include compounds, anthanthrone pigments, dibenzpyrenequinone pigments, pyranthrone pigments, trisazo pigments, monoazo pigments, indigo pigments, quinacridone pigments, asymmetric quinocyanine pigments, quinocyanine, and amorphous silicon described in JP-A No. 54-143645. .

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

  Examples of the binder resin include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic acid ester, methacrylic acid ester, vinylidene fluoride, and trifluoroethylene, polyvinyl alcohol, polyvinyl acetal, and polycarbonate. , Polyester, polysulfone, polyphenylene oxide, polyurethane, cellulose resin, phenol resin, melamine resin, silicon resin, epoxy resin and the like.

  The charge transport layer can be formed by applying a solution of a charge transport compound onto the charge generation layer and curing it by an appropriate treatment. In the case where the charge transport layer is a layer forming the surface of the electrophotographic photoreceptor, the charge transport layer is obtained by applying a solution of the first and second charge transport compounds as the mixture onto the charge generation layer. Can be formed by curing with radiation or the like as described above. When a surface protective layer is further provided on the charge generation layer, the charge transport layer is coated with a solution comprising a charge transport compound and a binder resin on the charge generation layer in the same manner as the charge generation layer. It can be formed by curing the film with a suitable treatment.

  The surface protective layer can be formed by applying a solution of the first and second charge transporting compounds on the charge transporting layer and curing it by radiation or the like as described above. Thus, the said charge transportable cured film can be used as the said charge transport layer, or can be used as a surface protective layer which has a charge transport capability. Therefore, in such an electrophotographic photoreceptor composed of a plurality of stacked layers, the photosensitive layer means a charge generation layer and a charge transport layer, or a charge generation layer, a charge transport layer and a surface protective layer. To do.

  When the first charge transporting compound is used in the charge transporting layer, the charge transporting compound is the first represented by the general formula (1) with respect to the total amount of the charge transporting layer film after polymerization and curing. It is desirable that the charge transporting compound in which the bonding site between A and P1 and Z of one charge transporting compound is replaced with a hydrogen atom is contained in an amount of 20% or more, preferably 40% or more in terms of molecular weight. When the content of the first charge transporting compound is less than 20%, the charge transporting ability is lowered, and problems such as a reduction in sensitivity and an increase in residual potential may occur. The film thickness of the charge transport layer is determined so that the total film thickness combined with the lower charge generation layer is 1 to 50 μm, and is preferably adjusted in the range of 5 to 30 μm.

When the first charge transporting compound is used for the surface protective layer, the charge transporting layer underneath is a suitable charge transporting material, for example, a heterocyclic ring such as poly-N-vinylcarbazole or polystyrylanthracene, or a condensed polyvalent compound. Polymer compounds having ring aromatics, heterocyclic compounds such as pyrazoline, imidazole, oxazole, triazole and carbazole, triarylalkane derivatives such as triphenylmethane, triarylamine derivatives such as triphenylamine, phenylenediamine derivatives, N -A solution obtained by dispersing / dissolving a low molecular weight compound such as phenylcarbazole derivative, stilbene derivative, hydrazone derivative and an appropriate binder resin (selectable from the aforementioned resin for charge generation layer) in a solvent is described above. And can be formed by coating and drying.

  In this case, the ratio of the charge transport material to the binder resin is preferably 30 to 100, preferably 50 to 100, when the total weight of both is 100. It is selected appropriately. If the amount of the charge transporting material is less than that, the charge transporting ability may be lowered, and problems such as a decrease in sensitivity and an increase in residual potential may occur. The film thickness of the charge transport layer is determined so that the total film thickness combined with the upper surface protective layer is 1 to 50 μm, and is preferably adjusted in the range of 5 to 30 μm.

Here, Eox the oxidation potential of the general formula (2) Eox ⁰² the oxidation potential of the second charge-transporting compound represented by said first charge-transporting compound represented by the general formula (1) ⁰¹ Then, it is desirable that the oxidation potential difference between the two charge transporting compounds satisfy the relationship shown in the following formula 1.
(Equation 1)
Eox ⁰¹ -1 ≦ Eox ⁰²
The oxidation potential can be measured by the following method.
(Measurement method of oxidized electrons)
Using a SCE (saturated calomel electrode) as a reference electrode, a 0.1 N (n-Bu) ₄ N ⁺ ClO ₄ ⁻ / CH ₂ Cl ₂ solution is used as the electrolyte, and the potential applied to the working electrode (platinum) by the potential sweeper The current-potential curve obtained by sweeping is measured, and the oxidation potential is measured.

Specifically, the sample is dissolved in a 0.1 N (n-Bu) ₄ N ⁺ ClO ₄ / CH ₂ Cl ₂ solution to a concentration of about 5 to 10 mmol%. Then, a voltage is applied to the sample solution with the working electrode, and the current change when the voltage is continuously changed from 0 (V) → + 1.5 (V) → 0 (V) is measured. Get a curve. When sweeping from 0 (V) to +1.5 (V) in this current-potential curve, the potential at the peak top position where the current value showed a peak at the position closest to the 0 (V) side is expressed as Eox ^a (V ), And when it is swept from +1.5 (V) to 0 (V), let Eox ^b (V) be the potential at the peak top position where the current value peaked at the position closest to 0 (V) side, Let (Eox ^a + Eox ^b ) / 2 (V) be the oxidation potential (Eox (V)).

  Ideally, the combination of the first charge transporting compound and the second charge transporting compound has a common central skeleton having a charge transporting function, and a combination of materials differing only in functional groups is electrically Most preferable in improving the characteristics. When two types of charge transporting compounds that do not satisfy the above-described oxidation potential relationship are used in combination, there is no problem in mechanical strength, but the electrical characteristics tend to deteriorate.

  In the case of a photosensitive layer composed of a single layer, a solution containing at least the first charge transporting compound, the second charge transporting compound and a charge generating material is used as an appropriate undercoat layer or intermediate layer. A single-layer photosensitive layer composed of a charge generating substance and a charge transporting substance provided on the conductive support. Any of the cases where polymerization or crosslinking is performed after coating a solution containing at least the first charge transporting compound and the second charge transporting compound on the layer is possible.

  Furthermore, various additives can be added to the photosensitive layer as necessary. Examples of the additive include an antioxidant, a polymerization inhibitor, an anti-degradation agent such as an ultraviolet absorber and a halogen compound, a lubricant such as tetrafluoroethylene resin and carbon fluoride, and a monofunctional or polyfunctional chain polymerizable property. Examples thereof include a curability-imparting agent such as a polymerizable monomer having a functional group, a thermoplastic resin, a known charge transport compound, and a known charge generating substance.

  Table 1 below shows the first charge transporting compound according to the present invention, and Table 2 shows typical examples of the second charge transporting compound, but the present invention is not limited to these.

The process cartridge of the present invention comprises the above-described electrophotographic photosensitive member of the present invention, charging means for charging the electrophotographic photosensitive member, and developing means for developing the electrostatic latent image formed on the charged electrophotographic photosensitive member with toner. One or more components such as cleaning means for removing toner remaining on the electrophotographic photosensitive member after transfer of the toner image formed on the electrophotographic photosensitive member, It is configured to be detachable from the main body of an electrophotographic apparatus such as a laser beam printer. The process cartridge of the present invention may appropriately include other means in addition to the electrophotographic photosensitive member and the above-described components.

  The electrophotographic apparatus of the present invention includes the above-described electrophotographic photosensitive member of the present invention, the charging unit, an exposing unit that forms an electrostatic latent image on the charged electrophotographic photosensitive member by exposure, the developing unit, Transfer means for transferring the toner image formed on the electrophotographic photosensitive member to a transfer material. In addition to the above, the electrophotographic apparatus according to the present invention may include other means such as fixing means for fixing an unfixed toner image on a transfer material by heating and pressing, and means for detachably supporting the process cartridge. May be included as appropriate.

  FIG. 1 schematically shows an electrophotographic apparatus having a process cartridge having the electrophotographic photosensitive member of the present invention. In the figure, an electrophotographic photosensitive member 1 that is driven to rotate at a predetermined peripheral speed in the direction of an arrow about an axis 2, a primary charging means 3 that charges the electrophotographic photosensitive member 1, and a charged electrophotographic photosensitive member 1. Development means 5 for developing the electrostatic latent image with toner, and cleaning means 9 for removing the toner remaining on the electrophotographic photoreceptor 1 after the transfer of the toner image formed on the electrophotographic photoreceptor 1. The electrophotographic photosensitive member 1, the primary charging unit 3, the developing unit 5, and the cleaning unit 9 are integrally supported. The process cartridge 11 is detachably attached to the apparatus main body using guide means such as a rail 12 of the apparatus main body.

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

  The electrophotographic photoreceptor 1 is driven to rotate at a predetermined peripheral speed in the direction of the arrow about the shaft 2. In the rotation process, the electrophotographic photosensitive member 1 is uniformly charged at a predetermined positive or negative potential on its peripheral surface by the primary charging unit 3, and then from an image exposure unit (not shown) such as slit exposure or laser beam scanning exposure. The image exposure light 4 is received. In this way, electrostatic latent images are sequentially formed on the peripheral surface of the photoreceptor 1. When the electrophotographic apparatus is a copying machine or a printer, the image exposure light 4 is reflected or transmitted from the original, or is read as a signal by a sensor, converted into a signal, and laser beam scanning performed according to this signal. Light emitted by driving the LED array, driving the liquid crystal shutter array, or the like.

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

  After the image transfer, the surface of the photoreceptor 1 is cleaned by removing the transfer residual toner by the cleaning unit 9, and is further subjected to a charge removal process by the pre-exposure light 10 from the pre-exposure unit (not shown), and then repeatedly. Used for image formation. When the primary charging unit 3 is a contact charging unit using a charging roller or the like, the pre-exposure need not be performed.

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

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In the examples, “parts” represents parts by mass.
<Example 1>
First, a coating material for the conductive layer was prepared by the following procedure. 50 parts of conductive titanium oxide powder coated with tin oxide containing 10% antimony oxide, 25 parts of phenol resin, 20 parts of methyl cellosolve, 5 parts of methanol, and a silicone compound (polydimethylsiloxane polyoxyalkylene copolymer, 0.002 part of an average molecular weight of 3000) was prepared by dispersing for 2 hours in a sand mill using 1 mm diameter glass beads. This paint was applied on an aluminum cylinder having a diameter of 30 mm by a dip coating method and dried at 150 ° C. for 30 minutes to form a conductive layer having a thickness of 18 μm.

  Next, 5 parts of N-methoxymethylated nylon was dissolved in 95 parts of methanol to prepare an intermediate layer coating material. This paint was applied onto the conductive layer by a dip coating method and dried at 100 ° C. for 20 minutes to form a 0.5 μm intermediate layer.

  Next, 3 parts of oxytitanium phthalocyanine having strong peaks at 9.0 degrees, 14.2, 23.9 degrees, and 27.1 degrees with black angles 2θ ± 0.2 degrees in X-ray diffraction of CuKα, polyvinyl Disperse 3.5 parts of butyral (trade name ESREC BM2, manufactured by Sekisui Chemical Co., Ltd.) and 35 parts of cyclohexanone with a sand mill using 1 mm diameter glass beads for 2 hours, and then add 60 parts of ethyl acetate. A charge generation layer coating was prepared. This paint was applied onto the intermediate layer by a dip coating method and dried at 90 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

  Next, Compound Example Nos. 18 charge transporting compounds and Compound Example No. 18 charge transporting compound having a hydroxyl group of 0.006 parts (0.01% with respect to the charge transporting compound) was dissolved in a mixed solvent of 50 parts of monochlorobenzene and 30 parts of dichloromethane to obtain a coating material for charge transporting layer. Was prepared. The paint is coated on the charge generation layer, and the paint is cured by irradiating the paint film with an electron beam under conditions of an acceleration voltage of 150 kV and an irradiation dose of 15 Mrad to form a charge transport layer having a thickness of 15 μm. Photoconductor 1 was produced.

  The photoconductor 1 is mounted on a laser beam printer (Laser Writer 16 / 600PS: manufactured by Apple Inc.) modified so that the light amount and the charge setting can be changed, and is in a normal temperature and humidity environment (23 ° C./55% RH) (N / N ), Charging was set so that the initial dark portion potential (Vd) was −700 (V).

  The initial characteristics of the photoreceptor 1 were measured by the following method under the conditions of transfer current: +5.5 μA and process speed: 96 mm / sec.

The photosensitive member 1 of the charged printer is irradiated with laser light having a wavelength of 780 (nm) to reduce the amount of light (EΔ500, sensitivity required to reduce the potential of −700 (V) to −200 (V). Measured). Furthermore, the potential when irradiated with light of 20 μJ / cm ² (20 cJ / m ² ) was measured as the residual potential (Vr).

  Then, the environment was changed to a high temperature and high humidity environment (32 ° C./85% RH) (H / H), and the amount of fluctuation (ΔVl) of Vr from room temperature and normal humidity was measured.

  The surface potential of the photoreceptor was measured using a surface potential meter (model 344: manufactured by Trek) with a modified LBP cartridge, a potential probe (model 6000B-8: manufactured by Trek) attached to the development position. .

  Next, the photoconductor 1 newly produced by the same method as described above is mounted on a modified machine similar to the above, and continuously 20000 sheets in a normal temperature and low humidity environment (23 ° C./10% RH) (N / L). The film thickness before and after the endurance of the photosensitive member 1 was measured using an overcurrent film thickness meter (manufactured by Karl Fischer) to determine the amount of scraping.

  In addition, the photo memory was measured as follows. In order to measure the photo memory for white light, the photoconductor 1 newly produced by the same method as described above is mounted on a remodeling machine similar to the above, and the initial dark potential (Vd) in a low temperature and low humidity environment (N / N). / Charge and exposure light quantity are set so that the initial bright part potential (Vl) becomes -700 (V) /-200 (V), and then the photosensitive member 1 is masked so that dark parts and bright parts are formed. The sample was irradiated with light at 3000 lux for 20 minutes under a fluorescent lamp and then allowed to stand for 5 minutes, and the surface potential of the photoreceptor 1 was measured as described above. The absolute value (ΔVd) of the amount of change from the initial dark portion potential after standing was used as a photo memory.

From these results, the photoreceptor 1 has a low residual potential, very little potential fluctuation and photo memory in various environments, and a small amount of film thickness reduction, so that a clear image can be stably obtained over a long period of time. It has become clear that it has excellent electrical properties and mechanical strength.
<Examples 2 to 20>
As shown in Table 3, photoconductors 2 to 20 were prepared in the same manner as in Example 1, except that the type and addition amount of the chain polymerizable charge transporting compound and the charge transporting compound having a hydroxyl group in Example 1 were changed. Were prepared and evaluated in the same manner. The results are shown in Table 3.
<Comparative Examples 1-8>
As shown in Table 4, the comparative photoconductors 1 to 3 were prepared in the same manner as in Example 1 except that the chain polymerizable charge transporting compound of Example 1 and the type and addition amount of the charge transporting compound having a hydroxyl group were changed. 8 was prepared and evaluated in the same manner. The results are shown in Table 4.
<Example 21>
Compound Example Nos. 18 charge transporting compounds and Compound Example No. Charge transporting is carried out by dissolving 0.6 part of a charge transporting compound having 18 hydroxyl groups and 1.0 part of a thermal polymerization initiator of the following structural formula (A) in a mixed solvent of 50 parts of monochlorobenzene and 30 parts of dichloromethane. A layer coating was prepared. This paint was coated on the charge generation layer, and the coating film was heated and cured at 150 ° C. for 1.5 hours to form a charge transport layer having a thickness of 15 μm. This was evaluated in the same manner as in Example 1. The results are shown in Table 3.

<Examples 22 and 23>
As shown in Table 3, photoconductors 22 and 23 were prepared in the same manner as in Example 21, except that the type and amount of the chain polymerizable charge transporting compound and the charge transporting compound having a hydroxyl group in Example 21 were changed. Were prepared and evaluated in the same manner. The results are shown in Table 3.
<Comparative Examples 9-11>
As shown in Table 4, the comparative photoconductors 9 to 9 were prepared in the same manner as in Example 21, except that the type and amount of the chain polymerizable charge transporting compound of Example 21 and the charge transporting compound having a hydroxyl group were changed. 11 was prepared and evaluated in the same manner. The results are shown in Table 4.
<Example 24>
Compound Example Nos. 18 charge transporting compounds and Compound Example No. Charge transporting is carried out by dissolving 0.6 part of a charge transporting compound having 18 hydroxyl groups and 1.0 part of a photopolymerization initiator of the following structural formula (B) in a mixed solvent of 50 parts of monochlorobenzene and 30 parts of dichloromethane. A layer coating was prepared. This paint is coated on the charge generation layer and cured for 60 seconds at a light intensity of 500 mW / cm ² (5000 W / m ² ) using a metal halide lamp to form a charge transport layer having a thickness of 15 μm. 24 was obtained. This was evaluated in the same manner as in Example 1. The results are shown in Table 5.

<Examples 25 and 26>
As shown in Table 5, photoconductors 25 and 26 were prepared in the same manner as in Example 24 except that the type and addition amount of the chain polymerizable charge transporting compound and the charge transporting compound having a hydroxyl group in Example 24 were changed. Were prepared and evaluated in the same manner. The results are shown in Table 5.
<Comparative Examples 12-14>
As shown in Table 7, the comparative photoconductors 12 to 12 were prepared in the same manner as in Example 24 except that the type and addition amount of the chain polymerizable charge transporting compound and the hydroxyl group-containing charge transporting compound of Example 24 were changed. 14 was produced and evaluated in the same manner. The results are shown in Table 7.
<Example 27>
The charge generation layer was produced in the same manner as in Example 1. Next, 20 parts of a styryl compound of the following structural formula (C) and 10 parts of a polycarbonate resin (number average molecular weight 20000) having a repeating unit of the following structural formula (D) are mixed in a mixed solvent of 50 parts of monochlorobenzene and 20 parts of dichloromethane. A charge transport layer was formed on the charge generation layer using a coating solution for a charge transport layer prepared by dissolving in the solution. The thickness of the charge transport layer at this time was 15 μm.

Subsequently, Compound Example No. 1 in Table 1 was used. No. 19 charge transporting compound 60 parts and Table 2 Compound Example No. A surface protective layer coating material was prepared by dissolving 0.006 part of a charge transporting compound having 6 hydroxyl groups in 150 parts of n-propyl alcohol. The coating is coated on the charge transport layer, and the coating is cured by irradiating the coating with an electron beam under conditions of an acceleration voltage of 150 kV and an irradiation dose of 15 Mrad to form a surface protective layer having a thickness of 5 μm. 27 was obtained. This was evaluated in the same manner as in Example 1. The results are shown in Table 5.
<Examples 28 to 46>
As shown in Table 5, photoconductors 28 to 46 were prepared in the same manner as in Example 27 except that the type and addition amount of the chain polymerizable charge transporting compound of Example 27 and the charge transporting compound having a hydroxyl group were changed. Were prepared and evaluated in the same manner. The results are shown in Table 5.
<Comparative Examples 15-22>
As shown in Table 7, the comparative photoconductors 15 to 15 were prepared in the same manner as in Example 27, except that the type and amount of the chain polymerizable charge transporting compound of Example 27 and the charge transporting compound having a hydroxyl group were changed. 22 was prepared and evaluated in the same manner. The results are shown in Table 7.
<Example 47>
The charge transport layer was produced in the same manner as in Example 27. Subsequently, Compound Example No. 1 in Table 1 was used. No. 19 charge transporting compound 60 parts and Table 2 Compound Example No. A surface protective layer coating material was prepared by dissolving 0.6 part of a charge transporting compound having 6 hydroxyl groups and 1.0 part of a thermal polymerization initiator of the following structural formula (A) in 150 parts of n-propyl alcohol. . This paint was coated on the charge transport layer, and this coating film was heated and cured at 150 ° C. for 1.5 hours to form a surface protective layer having a thickness of 5 μm. This was evaluated in the same manner as in Example 1. The results are shown in Table 6.

<Examples 48 and 49>
As shown in Table 6, photoconductors 48 and 49 were prepared in the same manner as in Example 47, except that the type and addition amount of the chain polymerizable charge transporting compound and the hydroxyl group-containing charge transporting compound of Example 47 were changed. Were prepared and evaluated in the same manner. The results are shown in Table 6.
<Comparative Examples 23-25>
As shown in Table 7, Comparative Photoreceptor 2 was prepared in the same manner as in Example 47, except that the type and addition amount of the chain polymerizable charge transporting compound of Example 47 and the charge transporting compound having a hydroxyl group were changed.
3-25 were produced and evaluated similarly. The results are shown in Table 7.
<Example 50>
The charge transport layer was produced in the same manner as in Example 27. Subsequently, Compound Example No. 1 in Table 1 was used. No. 19 charge transporting compound 60 parts and Table 2 Compound Example No. A surface protective layer coating material was prepared by dissolving 0.6 parts of a charge transporting compound having 6 hydroxyl groups and 1.0 part of a photopolymerization initiator of the following structural formula (B) in 150 parts of n-propyl alcohol. . This paint was coated on the charge transport layer, and this coating film was cured for 60 seconds at a light intensity of 500 mW / cm ² using a metal halide lamp to form a surface protective layer having a thickness of 5 μm, whereby a photoreceptor 50 was obtained. . This was evaluated in the same manner as in Example 1. The results are shown in Table 6.

<Examples 51 and 52>
As shown in Table 6, photoconductors 51 to 52 were prepared in the same manner as in Example 50 except that the type and amount of the chain polymerizable charge transporting compound and the hydroxyl group-containing charge transporting compound in Example 50 were changed. Were prepared and evaluated in the same manner. The results are shown in Table 6.
<Example 53>
The charge generation layer was produced in the same manner as in Example 1. Subsequently, Compound Example No. 1 in Table 1 was used. 18 charge transporting compounds and Compound Example No. 0.006 part of a charge transporting compound having 18 hydroxyl groups and 6 parts of a curable monomer of the following structural formula (E) (manufactured by Nippon Kayaku Co., Ltd., Kayarad DPHA) are mixed with 50 parts of monochlorobenzene and 30 parts of dichloromethane. It melt | dissolved in the mixed solvent and prepared the coating material for charge transport layers. The paint is coated on the charge generation layer, and the paint is cured by irradiating the paint film with an electron beam under conditions of an acceleration voltage of 150 kV and an irradiation dose of 15 Mrad to form a charge transport layer having a thickness of 15 μm. A photoreceptor 53 was produced. This was evaluated in the same manner as in Example 1. The results are shown in Table 6.

<Comparative Examples 26-28>
As shown in Table 7, the comparative photoconductors 26 to 26 were prepared in the same manner as in Example 50 except that the type and amount of the chain polymerizable charge transporting compound and the hydroxyl group-containing charge transporting compound in Example 50 were changed. 28 was prepared and evaluated in the same manner. The results are shown in Table 7.
<Comparative Example 29>
The charge generation layer was produced in the same manner as in Example 1. Subsequently, Compound Example No. 1 in Table 1 was used. 19 parts of a charge transporting compound of 19 and 0.6 part of a charge transporting compound of the following structural formula (C) (1.0% by mass with respect to the charge transporting compound) are mixed with 50 parts of monochlorobenzene and 30 parts of dichloromethane. It melt | dissolved in the mixed solvent and prepared the coating material for charge transport layers. The coating is coated on the charge generation layer, and the coating is cured by irradiating the coating with an electron beam under conditions of an acceleration voltage of 150 kV and an irradiation dose of 15 Mrad to form a charge transport layer having a thickness of 15 μm. A body 29 was prepared and evaluated in the same manner. The results are shown in Table 7.

<Comparative Example 30>
The charge generation layer was produced in the same manner as in Example 1. Subsequently, Compound Example No. 1 in Table 1 was used. 19 charge transporting compounds of 60, 0.6 parts of charge transporting compound of the following structural formula (F) (1.0% by mass with respect to the charge transporting compound), 50 parts of monochlorobenzene and 30 parts of dichloromethane. It melt | dissolved in the mixed solvent and prepared the coating material for charge transport layers. The coating is coated on the charge generation layer, and the coating is cured by irradiating the coating with an electron beam under conditions of an acceleration voltage of 150 kV and an irradiation dose of 15 Mrad to form a charge transport layer having a thickness of 15 μm. A body 30 was made and evaluated similarly. The results are shown in Table 7.

  In the table below, “electron beam CTL” means a charge transport layer prepared by curing a paint by electron beam irradiation, and “thermal CTL” means charge transport produced by curing a paint by heating. “UV CTL” means a charge transport layer prepared by curing a paint by irradiation with ultraviolet rays. In the table below, “electron beam OCL” means a surface protective layer prepared by curing a paint by electron beam irradiation, and “thermal OCL” means a surface protective layer prepared by curing the paint by heating. The term “ultraviolet OCL” means a surface protective layer produced by curing a paint by irradiation with ultraviolet rays.

  From the above experimental results, the charge transporting compound having a hydroxyl group in the same molecule, more preferably having an oxidation potential as close as possible to the oxidation potential of the charge transporting compound having an acryloyloxy group or a methacryloyloxy group, and The charge transporting compound having a hydroxyl group in the same molecule is 0.01 to 5.0% by mass, more preferably 0.05 to 2.00%, based on the charge transporting compound having at least an acryloyloxy group or a methacryloyloxy group. It is clear that an electrophotographic photoreceptor excellent in mechanical strength and electrical characteristics can be obtained when it is contained in a mass% and cured by an electron beam.

1 is a schematic view showing an embodiment of a process cartridge having an electrophotographic photosensitive member of the present invention and an electrophotographic apparatus having the process cartridge. FIG.

Explanation of symbols

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

Claims (11)

In an electrophotographic photosensitive member having a conductive support and a photosensitive layer provided on the conductive support,
The photosensitive layer forms the surface of the electrophotographic photosensitive member and is composed of a single layer or a plurality of stacked layers,
The photosensitive layer composed of a single layer, or the layer forming the surface of the electrophotographic photoreceptor among the photosensitive layers composed of a plurality of layers has at least an acryloyloxy group or a methacryloyloxy group. It is obtained by performing at least one of or both of polymerization and crosslinking of the first charge transporting compound in a mixture containing one charge transporting compound and a second charge transporting compound having a hydroxyl group. Formed of hardened material,
The electrophotographic photoreceptor, wherein the mixture contains 0.01 to 5.0% by mass of the second charge transporting compound with respect to the first charge transporting compound.   2. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer composed of the plurality of layers includes a charge generation layer and a charge transport layer, and the charge transport layer is a layer forming a surface of the electrophotographic photosensitive member.   2. The electron according to claim 1, wherein the photosensitive layer composed of the plurality of layers includes a charge generation layer, a charge transport layer, and a surface protective layer, and the surface protective layer is a layer that forms a surface of the electrophotographic photosensitive member. Photoconductor. The electrophotographic photoreceptor according to any one of claims 1 to 3, wherein the first charge transporting compound is a compound represented by the following general formula (1).

  The electrophotographic photosensitive member according to claim 4, wherein a + b × d in the general formula (1) represents an integer of 2 or more. The electrophotographic photoreceptor according to any one of claims 1 to 5, wherein the second charge transporting compound is a compound represented by the following general formula (2).

  The said mixture contains 0.05-2.0 mass% of said 2nd charge transport compound with respect to said 1st charge transport compound, The any one of Claim 1 to 6 characterized by the above-mentioned. The electrophotographic photoreceptor described in 1.   The photosensitive layer composed of the single layer or the layer forming the surface of the electrophotographic photosensitive member is a layer produced by curing the mixture by any one of heat, light, and radiation. The electrophotographic photosensitive member according to any one of claims 1 to 7.   8. The photosensitive layer comprising the single layer or the layer forming the surface of the electrophotographic photosensitive member is a layer produced by curing the mixture with an electron beam. The electrophotographic photosensitive member according to any one of the above. 10. The electrophotographic photosensitive member according to claim 1, charging means for charging the electrophotographic photosensitive member, and development for developing an electrostatic latent image formed on the charged electrophotographic photosensitive member. A process cartridge mounted on an electrophotographic apparatus having means and a cleaning means for removing toner from the surface of the electrophotographic photosensitive member,
The electrophotographic photosensitive member and at least one means selected from the group consisting of the charging means, the developing means, and the cleaning means are integrally supported and configured to be detachable from the main body of the electrophotographic apparatus. Feature process cartridge.   10. The electrophotographic photosensitive member according to claim 1, charging means for charging the electrophotographic photosensitive member, and exposure means for forming an electrostatic latent image on the charged electrophotographic photosensitive member by exposure. And developing means for developing the electrostatic latent image formed on the electrophotographic photosensitive member with toner, and transfer means for transferring the toner image formed on the electrophotographic photosensitive member to a transfer material. An electrophotographic device.

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