JP2005189766A - Electrophotographic photoreceptor, process cartridge, and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which exhibits stable electrophotographic properties regardless of the operating environment in a high-speed copying machine, a printer or the like and also exhibits good duration properties by using an intermediate layer or a charge generating layer having rectification function of the same polarity as potential by electrostatic charge regardless of general electric conduction, and to provide a process cartridge with the electrophotographic photoreceptor and an electrophotographic apparatus. <P>SOLUTION: In the electrophotographic photoreceptor obtained by stacking at least an undercoat layer, a charge generating layer and a charge transport layer in this order on a conductive substrate, the undercoat layer contains a material having ability to transfer charges of the same polarity as polarity of electrostatic charge and the charge generating layer contains at least a hole transport material and an electron transport material together with a charge generating material. The process cartridge with the electrophotographic photoreceptor and the electrophotographic apparatus are also provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  Conventionally, inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been widely used for electrophotographic photoreceptors. On the other hand, as an electrophotographic photosensitive member using an organic photoconductive substance, a photoconductive polymer represented by poly-N-vinylcarbazole and 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadi Those using a low molecular organic photoconductive substance such as azole, and those obtained by combining such organic photoconductive substance with various dyes and pigments are known.

  An electrophotographic photosensitive member using an organic conductive material has good film formability and can be produced by coating, and therefore has an advantage of providing an electrophotographic photosensitive member that is extremely high in productivity and inexpensive. Moreover, it has an advantage that the photosensitive wavelength range can be freely controlled by selecting a dye or a pigment to be used, and has been extensively studied so far. In recent years, the development of a functionally separated electrophotographic photoreceptor in which a charge generation layer containing an organic conductive dye or pigment and a charge transport layer containing a photoconductive polymer or a low molecular organic photoconductive material are laminated. However, sensitivity and durability, which have been regarded as disadvantages of conventional organic electrophotographic photoreceptors, have been remarkably improved, and this has become the mainstream of organic electrophotographic photoreceptors.

  On the other hand, when the photosensitive layer is formed directly on the conductive support, there are problems such as low charging ability and lack of potential stability during repeated use.

  If these potentials are not stable, the image density may not be stable, or the image may be fogged.

  For this reason, functions and adhesion as a barrier layer between the photosensitive layer and the conductive support due to barrier properties between the photosensitive layer and the support, and coverage of defects, dirt, deposits, scratches, etc. on the support surface. It has been proposed to provide an intermediate layer that functions as a layer.

As such an intermediate layer, polyamide (see Patent Documents 1 and 2), polyester (see Patent Documents 3 and 4), polyurethane (see Patent Documents 5 and 6), casein (see Patent Document 7), Polypeptide (see Patent Document 8), polyvinyl alcohol (see Patent Document 9), polyvinylpyrrolidone (see Patent Document 10), vinyl acetate-ethylene copolymer (see Patent Document 11), maleic anhydride Resins such as coalescence (see Patent Document 12), polyvinyl butyral (see Patent Documents 13 to 14), quaternary ammonium salt-containing polymer (see Patent Documents 15 to 16), and ethyl cellulose (see Patent Document 17). It is known to use.
JP-A-46-47344 JP-A-52-25638 JP-A-52-20836 JP 54-26738 A JP-A 49-10044 JP-A-53-89435 JP-A-55-103556 JP 53-48523 A JP 52-100240 A JP-A-48-30936 JP-A-48-261141 JP 52-10138 A JP-A-57-90639 JP 58-106549 A JP 51-126149 A JP-A-56-60448 JP-A-55-143564

  However, in an electrophotographic photoreceptor using an ordinary resin as an intermediate layer, the potential is likely to change due to the influence of the temperature and humidity environment, and the dark area potential is lowered by carrier injection from the support side due to the reduced barrier function under high temperature and humidity. There is a drawback that the density of the copied image becomes thin.

  In addition, when such an electrophotographic photosensitive member is used in an electrophotographic printer that performs reversal development, there is a problem that fog is likely to occur in an image under high temperature and high humidity.

  In particular, in a multilayer electrophotographic photosensitive member in which a photosensitive layer is formed by sequentially laminating a charge generation layer and a charge transport layer, the charge generation layer containing a high concentration of the charge generation material is located on the intermediate layer, so that the carrier from the support side A potential drop due to increased injection was more likely to occur, and even with a slight decrease in the barrier function of the intermediate layer, fogging was likely to occur in a reversal development type printer.

  The conventional intermediate layer by electrical conduction has a contradictory property that if the resistance is increased to ensure barrier properties, the residual potential increases, whereas if the resistance is decreased, the barrier properties become insufficient and fogging becomes severe.

  As a result of intensive research, the present inventors have found that a high-speed copying machine can be realized by using an intermediate layer or a charge generation layer having a rectifying action of the same polarity with respect to a charged potential, regardless of general electric conduction. The present inventors have found that printers and the like show stable electrophotographic characteristics regardless of the use environment and also show good characteristics in durability.

  That is, the present invention relates to an electrophotographic photosensitive member in which at least an undercoat layer, a charge generation layer, and a charge transport layer are laminated in this order on a conductive support, and the undercoat layer has a charge transfer having the same polarity as the charge polarity. An electrophotographic photosensitive member comprising a substance having a function, wherein the charge generation layer contains at least a hole transport substance and an electron transport substance together with the charge generation substance.

  Further, the present invention is characterized in that the electrophotographic photosensitive member and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means are integrally supported and are detachable from the electrophotographic apparatus. Process cartridge.

  The present invention also provides an electrophotographic apparatus comprising the electrophotographic photosensitive member, a charging unit, an exposure unit, a developing unit, and a transfer unit.

  As described above, according to the present invention, an electrophotographic photoreceptor having excellent potential characteristics and electrophotographic characteristics, a process cartridge and an electrophotographic apparatus having the electrophotographic photoreceptor can be provided.

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

In the present invention, the undercoat layer or the charge generation layer contains a compound having a transporting ability having the same polarity as the charged potential of the surface of the electrophotographic photosensitive member, and the charge generating layer further has a transporting ability having a reverse polarity. An electrophotographic photoreceptor comprising a compound. When the electrophotographic photosensitive member of the present invention is used with a negative charge, the undercoat layer contains an electron transport material, and the charge transport layer contains a hole transport material in addition to the electron transport material. Conversely, when used in positive charge, the undercoat layer is characterized by containing a hole transport material. The charge transport materials contained in the undercoat layer and the charge generation layer may be the same or different, and when they are different, the difference in the lowest unoccupied orbital level is preferably within ± 0.2 (eV). Examples of electrical properties required for the undercoat layer include volume resistivity and charge mobility. The volume resistivity of the undercoat layer is 1 × 10 ¹⁰ Ω · cm or more, more preferably 1 × 10 ¹² Ω · cm. It is preferable that this value does not vary depending on the use environment. However, when the undercoat layer has such a high resistance, charge injection from the support on which the photosensitive layer is laminated can be prevented, but charges generated by exposure in the charge generation layer cannot be transferred to the support. . Therefore, the undercoat layer needs to have a rectifying action, and the charge mobility at that time is 10 ⁻⁷ cm ² / V · sec or more, more preferably 10 ⁻⁶ cm ² / V · sec or more.

  It is important that the carrier pair generated by image exposure in the charge generation layer is quickly separated into holes and electrons. In the present invention, for the purpose of promoting the separation, an electron transport material and a hole transport are provided in the charge generation layer. Contains substances. However, when the charge generation layer has such a configuration, charge injection from the support occurs, and is particularly noticeable during repeated use. Therefore, a combination with an undercoat layer having a high resistance and a rectifying effect is effective.

  Next, the electrophotographic photosensitive member according to the present invention is specifically shown.

  The electrophotographic photosensitive member of the present invention has a structure in which at least an undercoat layer, a charge generation layer, and a charge transport layer are sequentially formed on a conductive support, and the undercoat layer has a transport ability having the same polarity as the charge polarity. And the charge generation layer contains both an electron transport material and a hole transport material.

  The conductive support of the electrophotographic photosensitive member of the present invention is a metal or alloy such as iron, copper, gold, silver, aluminum, zinc, titanium, lead, nickel, tin, antimony, indium, or an oxide of the metal, Carbon, conductive polymer, etc. can be used. The shape includes a drum shape such as a cylindrical shape and a columnar shape, and a belt shape and a sheet shape. The conductive material may be molded as it is, used as a paint, deposited, or processed by etching or plasma treatment. In the case of paint, the support can be made of paper, plastic, etc. as well as the metal and alloy.

  Furthermore, it is preferable to provide a conductive layer for the purpose of preventing interference fringes due to scattering when the support is coated with unevenness or defects, and when the image input is laser light, between the support and the undercoat layer. This can be formed by dispersing conductive powder such as carbon black, metal particles, and metal oxide in a binder resin. The film thickness of the conductive layer is preferably 5 to 40 μm, more preferably 10 to 30 μm.

In the electrophotographic photosensitive member of the present invention, an undercoat layer is provided between the conductive support or the conductive layer and the photosensitive layer. The undercoat layer functions as a charge injection control or an adhesive layer at the interface. The undercoat layer in the present invention has a transport function having the same polarity as the charged polarity of the electrophotographic photosensitive member surface. For example, when used in a negative polarity, the undercoat layer has a negative transport ability, that is, an electron transport ability, and its electron mobility is preferably 10 ⁻⁷ cm ² / V · sec or more, more preferably 10 ⁻⁶ cm ² / V · sec or more. The volume resistivity of the undercoat layer is 1 × 10 ¹⁰ Ω · cm or more, more preferably 1 × 10 ¹² Ω · cm.

The measurement of electron and hole mobility can be obtained by the time of flight method. It is known that the mobility depends on the electric field strength, and the value when the electric field strength is 3 × 10 ⁷ V / m is used. A specific measuring method is that a sample in which a charge generation layer and a charge transport layer are sequentially formed on a conductive support is sandwiched between glass transparent electrodes coated with a conductive material such as ITO coating, and consists of a power source and a resistance for current measurement. By forming a circuit, applying voltage, and irradiating the sample with light from the transparent electrode side, among the carriers generated in the charge generation layer, those injected into the charge transport layer are caused by hopping conduction in the charge transport phase. By observing the current waveform when traveling with an oscilloscope, the traveling time (t) of the carrier traveling in the sample is obtained. The speed (v = d / t) is obtained from the travel time (t) and the thickness (d) of the sample, and the speed (v) is the product of mobility (μ) and electric field strength (E) (v = μE). Therefore, the mobility (μ) of the sample can be obtained.

  The undercoat layer of the present invention contains a substance having a charge transport function, and the polarity varies depending on the charging polarity using the electrophotographic photosensitive member. In the case of using a negative charge, a substance having an electron transport function is used. On the other hand, in the case of using a positive charge, a substance having a hole transport function is used. Examples of the electron transport material include phthalimide, 4-nitrophthalimide, tetracyanoethylene, tetracyanoquinodimethane, chloranil, bromanyl, o-nitrobenzoic acid, trinitrofluorenone, quinone, diphenoquinone, naphthoquinone, anthraquinone, stilbenequinone, 2 , 4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone and the like, polymers obtained by polymerizing these electron withdrawing substances, and pigments such as azo pigments and perylene pigments. It is done. As the hole transport material, examples of the charge transport material include pyrene compounds, N-alkylcarbazole compounds, hydrazone compounds, N, N-dialkylaniline compounds, diphenylamine compounds, triphenylamine compounds, triphenylmethane compounds, pyrazoline compounds. , Styryl compounds, stilbene compounds, and the like.

  In addition to the charge transport material, a binder resin can be used at the same time. Specific examples of the binder resin include polyester, polyurethane, polyacrylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, polyamide. -Imido, nylon, polysulfone, polyallyl ether, polyacetal, butyral resin, benzal resin and the like.

  The thickness of the undercoat layer is preferably 0.1 to 10 μm, more preferably 0.3 to 5 μm. The amount of the charge transport material contained in the undercoat layer is preferably 20 to 100% by mass, more preferably 30 to 100% by mass, by mass ratio.

  The photosensitive layer of the electrophotographic photoreceptor used in the present invention is a function-separated type electrophotographic photoreceptor comprising a charge generation layer and a charge transport layer, and is formed on the undercoat layer in the order of a charge generation layer and a charge transport layer.

  The charge generation layer contains at least an electron transport material and a hole transport material in addition to the charge generation material.

  In the present invention, a general material can be used as the charge generating substance. In general, selenium-tellurium, pyrylium, thiapyrylium dyes, various central metals and crystal systems, specifically, phthalocyanine compounds having crystal types such as α, β, γ, ε, and X type, an anthropogenic charge generator Anthrone pigments, dibenzpyrenequinone pigments, pyranthrone pigments, trisazo pigments, disazo pigments, monoazo pigments, indigo pigments, quinacridone pigments, asymmetric quinocyanine pigments, quinocyanines and A-Si described in JP-A No. 54-143645 Can be mentioned.

  Examples of the electron transport material contained in the charge generation layer include phthalimide, 4-nitrophthalimide, tetracyanoethylene, tetracyanoquinodimethane, chloranil, bromanyl, o-nitrobenzoic acid, trinitrofluorenone, quinone, diphenoquinone, naphthoquinone, Electron-withdrawing substances such as anthraquinone, stilbenequinone, 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, and polymers obtained by polymerizing these electron-withdrawing substances, azo pigments, perylene And pigments such as pigments. Examples of the charge transport material contained in the charge generation layer include a pyrene compound, an N-alkylcarbazole compound, a hydrazone compound, an N, N-dialkylaniline compound, a diphenylamine compound, a triphenylamine compound, and a triphenylamine compound. Examples include phenylmethane compounds, pyrazoline compounds, styryl compounds, stilbene compounds, and the like.

  In addition to the charge generation material, a binder resin can also be used. Specific examples of the binder resin include polyester, polyurethane, polyacrylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, polyamide. -Imido, nylon, polysulfone, polyallyl ether, polyacetal, butyral resin, benzal resin and the like.

It is preferable that the lowest unoccupied orbital level (LUMO1) of the electron transport material contained in the undercoat layer and the lowest unoccupied orbital level (LUMO2) of the electron transport material contained in the charge generation layer satisfy the following formula (A). .
LUMO1 ≦ LUMO2 ± 0.2 (eV) (A)

In addition, the highest occupied orbital level (HOMO1) of the hole transport material contained in the undercoat layer and the highest occupied orbital level (HOMO2) of the hole transport material contained in the charge generation layer are represented by the following formula (B ) Is preferably satisfied.
HOMO1 ≦ HOMO2 ± 0.2 (eV) (B)
Note that the difference in the lowest unoccupied orbital (LUMO) level and the difference in the highest occupied orbital (HOMO) level correspond to the difference in reduction potential and oxidation potential, respectively.

The oxidation potential and reduction potential described here are measured by the following method. Saturated calomel electrode as a reference electrode, 0.1 N in an electrolytic solution ^{_{(n-Bu) 4 N +}} ClO 4 - with acetonitrile solution, sweeping the potential applied to the working electrode (platinum) by the potential sweeper, resulting current The potential when the potential curve showed a peak was taken as the oxidation potential. Specifically, the sample ^{_{0.1N (n-Bu) 4 N}} + ClO 4 - are dissolved so as to become a concentration of about 5～15Mmol% acetonitrile solution. A voltage was applied to the sample solution by a working electrode, and the voltage was linearly changed from a low potential (0 V) to a high potential (+1.5 V) (in the case of an oxidation potential. In the case of a reduction potential, 0 V to −1. 5V) is measured to obtain a current-potential curve. In this current-potential curve, the potential at the peak top position when the current value showed a peak (or the first peak when there are a plurality of peaks) was defined as an oxidation potential or a reduction potential.

  The amount of the charge generation material contained in the charge generation layer is preferably 20 to 80% by mass in mass ratio. The amount of the charge transport material contained in the charge generation layer is preferably 20 to 80% by mass by mass ratio. The ratio of the electron transport material to the hole transport material in the charge transport material is in the range of 1: 9 to 9: 1 by mass ratio, more preferably 3: 7 to 7: 3. The thickness of the charge generation layer is preferably 0.001 to 6 μm, and more preferably 0.01 to 2 μm.

  The charge transport layer contains at least a charge transport material, and when used in a negative charge, a material having an electron transport function is used, and conversely, when used in a positive charge, a material having a hole transport function is used. Used. Examples of the charge transport material that can be used in the charge transport layer include the materials that can be used in the undercoat layer and the charge generation layer described above.

  In addition to the charge transport material, a binder resin can also be used. Specific examples of the binder resin include polyester, polyurethane, polyacrylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, polyamide. -Imido, nylon, polysulfone, polyallyl ether, polyacetal, butyral resin, benzal resin and the like.

  When the charge transport layer is used on the outermost surface, a resin or monomer that cures or polymerizes using heat, light, or radiation, or a resin or monomer that cures or polymerizes having a photoconductive function is used for the charge transport layer. Is possible.

  The thickness of the charge transport layer is preferably 5 to 70 μm, more preferably 10 to 30 μm. The amount of the charge transport material contained in the charge transport layer is preferably 20 to 100% by mass, more preferably 30 to 100% by mass in mass ratio.

The electrophotographic photoreceptor of the present invention can be provided with a protective layer for the purpose of improving durability and electrophotographic characteristics. When providing a protective layer, the film thickness is preferably from 0.01 to 10 μm, more preferably from 0.1 to 7 μm. The protective layer may contain a charge generation material or a charge transport material. Further, it is possible to use a resin or monomer that cures and polymerizes using radiation, and further a resin or monomer that cures and polymerizes having a photoconductive function. Further, the protective layer may contain a conductive material such as a metal and its oxide, nitride, salt, alloy or carbon. Examples of such metal species include iron, copper, gold, silver, lead, zinc, nickel, tin, aluminum, titanium, antimony, and indium. Specifically, ITO, TiO ₂ , ZnO, SnO ₂ Al ₂ O ₃ or the like can be used. The conductive material is dispersed in the protective layer in the form of fine particles, but the particle diameter is preferably 0.001 to 5 μm, more preferably 0.01 to 1 μm, and the amount added to the protective layer Is preferably 1 to 70 mass%, more preferably 5 to 50 mass%. A titanium coupling agent, a silane coupling agent, various surface activities, and the like may be used as the dispersant. When the binder resin having a halogen group is contained in the charge generation layer, the mass ratio is preferably 0.1 to 50% by mass, more preferably 1 to 20%.

  Various additives such as an antioxidant, a photodegradation inhibitor, and a radiation degradation inhibitor may be used for each layer constituting the photosensitive layer. Further, the surface layer may contain various fluorine compounds, silane compounds, metal oxides or the like or fine particles thereof for the purpose of improving the lubricity and water repellency. A dispersant or a surfactant may be used for the purpose of improving these dispersibility. The content of these additives in the surface layer is preferably 1 to 70% by mass, more preferably 5 to 50% by mass.

  As a method for producing the electrophotographic photoreceptor of the present invention, methods such as vapor deposition and coating are used. The coating method can form films having various compositions in a wide range from a thin film to a thick film. Specifically, it is applied by a bar coater, knife coater, dip coating, spray coating, beam coating, electrostatic coating, roll coater, attritor, powder coating or the like.

  FIG. 2 shows a schematic configuration of an electrophotographic apparatus having a process cartridge having the electrophotographic photosensitive member of the present invention.

  In FIG. 2, reference numeral 4 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is rotationally driven in a direction of an arrow about a shaft 5 at a predetermined peripheral speed. In the rotation process, the electrophotographic photosensitive member 4 is charged uniformly (positive or negative) by a charging means (primary charging means) 6 on its peripheral surface, and then exposed to exposure means (such as slit exposure or laser beam scanning exposure). The exposure light 7 that is emphasized and modulated corresponding to the time-series electric digital image signal of the target image information output from the not-shown image is received. In this way, electrostatic latent images corresponding to target image information are sequentially formed on the peripheral surface of the electrophotographic photosensitive member 4.

  The formed electrostatic latent image is then developed with toner by the developing means 8 and taken out from a paper feeding unit (not shown) between the electrophotographic photosensitive member 4 and the transfer means 9 in synchronization with the rotation of the electrophotographic photosensitive member 4. The toner image formed and supported on the surface of the electrophotographic photosensitive member 4 is sequentially transferred by the transfer means 9 to the transfer material 10 thus fed.

  The transfer material 10 that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member, introduced into the image fixing means 11, and subjected to image fixing to be printed out as an image formed product (print or copy). .

  After the image is transferred, the surface of the electrophotographic photosensitive member 4 is cleaned by removing the toner remaining after the transfer by the cleaning unit 12, and is further subjected to the charge removal process by the pre-exposure light 13 from the pre-exposure unit (not shown). Used repeatedly for image formation.

  The charging means 6 may be a scorotron charger or a corotron charger using corona discharge, or a contact type charger using a known form such as a roller shape, a blade shape, or a brush shape. As a material of the member of the contact charger, an elastic body imparted with conductivity is generally used. The voltage applied to the contact charging member may be only a DC voltage or an oscillating voltage obtained by superimposing an AC voltage on a DC voltage. The oscillating voltage referred to here is a voltage whose voltage value periodically changes with time, and the AC voltage has a peak-to-peak voltage that is at least twice the charging start voltage of the electrophotographic photosensitive member when only the DC voltage is applied. It is preferable.

  When the charging unit 6 is a contact charging unit using a charging roller or the like, pre-exposure is not always necessary.

  In the present invention, a plurality of components such as the electrophotographic photosensitive member 4, the charging unit 6, the developing unit 8, and the cleaning unit 12 are housed in a container and integrally combined as a process cartridge 14. The process cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. For example, at least one of the charging unit 6, the developing unit 8 and the cleaning unit 12 is integrally supported together with the electrophotographic photosensitive member 1 to form a cartridge, and is detachable from the apparatus main body using a guide unit 15 such as a rail of the apparatus main body. Process cartridge.

  Further, when the electrophotographic apparatus is a copying machine, the exposure light 7 is reflected or transmitted light from the original, or the original is read by a sensor, converted into a signal, laser beam scanning performed in accordance with this signal, LED Light emitted by driving the array and driving the liquid crystal shutter array.

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

  Hereinafter, specific examples of the present invention will be described.

[Example 1]
The electrophotographic photosensitive member in this example is as follows. 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 (mass parts, hereinafter the same), 25 parts of resol type phenol resin, 20 parts of methoxypropanol, 5 parts of methanol and silicone oil (polydimethyl) A siloxane polyoxyalkylene copolymer (average molecular weight 3000) was prepared by dispersing 0.002 part in a sand mill apparatus using φ1 mm glass beads for 2 hours. The said coating material was apply | coated by the dip coating method on the φ30mm aluminum cylinder, and it dried for 30 minutes at 140 degreeC, and formed the 20-micrometer-thick conductive layer.

  Next, 5 parts of the compound (E1) and the following formula (1)

5 parts of a polycarbonate resin (viscosity average molecular weight 85000) having a repeating unit represented by is dissolved in 90 parts of chlorobenzene to prepare an undercoat layer coating material. The paint was applied onto the conductive layer by a dip coating method and dried at 100 ° C. for 20 minutes to form an undercoat layer having a thickness of 1.5 μm.

  Next, 3 parts of oxytitanium phthalocyanine having strong peaks at 9.0, 14.2, 23.9 and 27.1 degrees in Bragg angle 2θ ± 0.2 degrees in X-ray diffraction of CuKα, polyvinyl butyral (Product name ESREC BM-2, manufactured by Sekisui Chemical Co., Ltd.) 1 part, Compound (E1) 1 part, Compound (H1) and 35 parts of cyclohexanone were dispersed for 2 hours in a sand mill using φ1 mm glass beads, and thereafter 60 parts of ethyl acetate was added to the mixture to prepare a charge generation layer coating material. This paint was applied onto the undercoat layer by a dip coating method and dried at 50 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

  Next, 10 parts of the compound (H1) as a hole transport material and 10 parts of a polycarbonate resin (viscosity average molecular weight 22000) having a repeating unit of the following structural formula (1) are dissolved in a mixed solvent of 30 parts of monochlorobenzene and 30 parts of tetrahydrofuran. Thus, a paint for the charge transport layer was prepared. This paint was applied onto the charge generation layer by a dip coating method and dried with hot air at 100 ° C. for 60 minutes to form a charge transport layer having a thickness of 20 μm, whereby an electrophotographic photoreceptor was obtained.

  The prepared electrophotographic photosensitive member was subjected to continuous 5000 sheet durability using a laser beam printer EX from Canon Inc., and electrophotographic characteristics and image evaluation were performed. These results are shown in Table 3.

(Mobility measurement)
On the other hand, for mobility measurement, a sample is prepared on an aluminum sheet as follows. 3 parts of the oxytitanium phthalocyanine, 3 parts of polyvinyl butyral (trade name ESREC BM-2, manufactured by Sekisui Chemical Co., Ltd.) and 35 parts of cyclohexanone are dispersed in a sand mill using φ1 mm glass beads for 2 hours, and then acetic acid is added. 60 parts of ethyl was added to prepare a charge generation layer coating material. This paint was applied onto the undercoat layer by a dip coating method and dried at 50 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm. The charge generation layer coating material was applied with a wire bar and dried at 50 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

  Next, 5 parts of Compound Example (E1) and 5 parts of a polycarbonate resin (viscosity average molecular weight 22000) having a repeating unit of the following structural formula (1) are dissolved in 30 parts of chlorobenzene and coated on the charge generation layer with a wire bar. Then, it was dried at 100 ° C. for 60 minutes to form a charge transport layer having a thickness of 20 μm, and a sample for measuring electron mobility was prepared.

The electron mobility of this sample is assembled with the circuit shown in FIG. 1, and the charging potential is adjusted so that the electric field applied to the photosensitive layer is 3.0 × 10 ⁷ V / m. Shown in

(Resistance measurement)
The volume resistance value is measured by forming a surface layer on a polyethylene terephthalate (PET) film having platinum deposited on the surface, and using a volume resistance measuring device (4140B microammeter manufactured by Hewlett Packard).

[Examples 2 and 3]
Example 3 was prepared and evaluated in the same manner as in Example 1 except that the electron transport materials contained in the undercoat layer and the charge generation layer were changed to (E2) to (E3) in Example 1, and the results are shown in Table 3.

[Examples 4 and 5]
In Example 1, except that the electron transport material contained in the undercoat layer was changed to compounds (E2) to (E3), it was prepared and evaluated in the same manner as in Example 1, and the results are shown in Table 3.

[Comparative Example 1]
In Example 1, except that the electron transport material contained in the undercoat layer was changed to the compound (E4), it was prepared and evaluated in the same manner as in Example 1, and the results are shown in Table 3.

[Example 6]
As in Example 1, a 20 μm thick conductive layer was formed on an aluminum cylinder.

  Next, 5 parts of the compound (H2) and 5 parts of a polycarbonate resin (viscosity average molecular weight 85000) were dissolved in 90 parts of chlorobenzene to prepare an undercoat layer coating material. The paint was applied onto the conductive layer by a dip coating method and dried at 100 ° C. for 20 minutes to form an undercoat layer having a thickness of 1.5 μm.

  Next, 3 parts of oxytitanium phthalocyanine having strong peaks at 9.0, 14.2, 23.9 and 27.1 degrees in Bragg angle 2θ ± 0.2 degrees in X-ray diffraction of CuKα, polyvinyl butyral (Product name ESREC BM-2, manufactured by Sekisui Chemical Co., Ltd.) 1 part, Compound (E2) 1 part, Compound (H2) and 35 parts of cyclohexanone were dispersed for 2 hours in a sand mill using φ1 mm glass beads, and then 60 parts of ethyl acetate was added to the mixture to prepare a charge generation layer coating material. This paint was applied onto the undercoat layer by a dip coating method and dried at 50 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

  Next, 10 parts of the compound (E3) as an electron transport material and 10 parts of a polycarbonate resin (viscosity average molecular weight 22000) having a repeating unit of the following structural formula (1) are dissolved in a mixed solvent of 30 parts of monochlorobenzene and 30 parts of tetrahydrofuran. Then, a charge transport layer coating was prepared. This paint was applied onto the charge generation layer by a dip coating method and dried with hot air at 100 ° C. for 60 minutes to form a charge transport layer having a thickness of 20 μm, whereby an electrophotographic photoreceptor was obtained. The obtained electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The charging means has been modified so that the charging polarity is positive. The results are shown in Table 3.

[Example 7]
An electrophotographic photosensitive member was similarly prepared and evaluated except that the hole transport material used for the undercoat layer in Example 6 was replaced with the compound (H3) and the hole transport material used for the charge generation layer was replaced with the compound (H1). did.

[Comparative Example 2]
In Example 7, an electrophotographic photoreceptor was prepared and evaluated in the same manner except that the hole transport material used for the charge generation layer was replaced with the compound (H4).

[Comparative Example 3]
As an undercoat layer, a solution obtained by dissolving 5 g of methoxymethylated nylon (weight average molecular weight 32,000) and 10 g of alcohol-soluble copolymer nylon (weight average molecular weight 29,000) in 95 g of methanol was applied with a Meyer bar, and dried. Preparation and evaluation were performed in the same manner as in Example 1 except that an undercoat layer having a thickness of 1 μm was formed.

It is a figure which shows the example of the electron and hole mobility measurement of an electrophotographic photoreceptor. 1 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus including a process cartridge having the electrophotographic photosensitive member of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent electrode 2 Photosensitive layer 3 Conductive support body 4 Electrophotographic photoreceptor 5 Axis 6 Charging means 7 Exposure light 8 Developing means 9 Transfer means 10 Transfer material 11 Fixing means 12 Cleaning means 13 Pre-exposure light 14 Process cartridge 15 Guide means

Claims (9)

  In an electrophotographic photosensitive member in which at least an undercoat layer, a charge generation layer, and a charge transport layer are laminated in this order on a conductive support, the undercoat layer contains a substance having a charge transfer ability having the same polarity as the charge polarity. An electrophotographic photoreceptor, wherein the charge generation layer contains at least a hole transport material and an electron transport material together with the charge generation material.   2. The electrophotographic photosensitive member according to claim 1, wherein the substance having a charge transfer ability having the same polarity as the charged polarity is an electron transporting substance.   The electrophotographic photosensitive member according to claim 1, wherein the substance having a charge transfer ability having the same polarity as the charged polarity is a hole transport substance. The lowest unoccupied orbital level (LUMO1) of the electron transport material contained in the undercoat layer and the lowest unoccupied orbital level (LUMO2) of the electron transport material contained in the charge generation layer satisfy the following formula (A): The electrophotographic photosensitive member according to claim 2.
LUMO1 ≦ LUMO2 ± 0.2 (eV) (A) The highest occupied orbital level (HOMO1) of the hole transport material contained in the undercoat layer and the highest occupied orbital level (HOMO2) of the hole transport material contained in the charge generation layer are represented by the following formula (B The electrophotographic photosensitive member according to claim 3, wherein:
HOMO1 ≦ HOMO2 ± 0.2 (eV) (B) 6. The volume resistance of the undercoat layer is 1 × 10 ¹⁰ Ω · cm or more, and the mobility of the undercoat layer is 1 × 10 ⁻⁷ cm ² / V · sec or more. The electrophotographic photosensitive member according to any one of the above. The volume resistance of the undercoat layer is 1 × 10 ¹² Ω · cm or more, and the mobility of the undercoat layer is 1 × 10 ⁻⁶ cm ² / V · sec or more. The electrophotographic photosensitive member according to any one of the above.   The electrophotographic photosensitive member according to any one of claims 1 to 7 and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means are integrally supported, and are detachable from the electrophotographic apparatus. A process cartridge characterized by being.   An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1, a charging unit, an exposure unit, a developing unit, and a transfer unit.

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