JP4850196B2 - Electrophotographic photoreceptor, method for producing the same, and image forming apparatus and process cartridge using the same - Google Patents

Description

  The present invention relates to an electrophotographic photoreceptor for use in electrophotographic apparatuses and process cartridges such as copying machines, printers and facsimiles, and a method for producing the same, and particularly has electrophotographic characteristics excellent in environmental stability and suitable for mass production. The present invention relates to an electrophotographic photoreceptor and a method for producing the same.

  In recent years, the advantages of electrophotographic devices such as high speed, low noise, high image quality, and the ability to record on plain paper have been attracting attention. It is becoming popular. Furthermore, as a recent trend, in the field of printers and facsimiles, the form of use is shifting from office use to personal use, and further miniaturization, cost reduction, and maintenance-free are required. On the other hand, with the improvement of image processing techniques such as colorization of documents, higher resolution and higher quality image forming techniques are required.

  As a photoconductor used in the electrophotographic apparatus, an organic photoconductor made of an organic photoconductive material having advantages such as low cost and non-pollution has been actively developed, so that it can be installed in many apparatuses. It has become. Most of these practically used photoreceptors are multilayer photoreceptors in which a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material are sequentially formed on a conductive support. By separating the functions in this way, the characteristics such as sensitivity and durability required for the electrophotographic apparatus have been satisfied. Among them, a photoconductor having absorption in the oscillation wavelength region of a semiconductor laser, that is, a near-infrared wavelength region, has been actively developed. In particular, an electrophotographic photoconductor using an organic pigment such as phthalocyanine as a charge generation material. Is attracting attention.

  There are a coating method and a vapor deposition method as a method for forming a charge generation layer using an organic pigment such as phthalocyanine as a charge generation material. The coating method includes techniques such as dip coating and spray coating, but the dip coating method immerses the conductive support in a dispersion paint composed of at least a specific crystal type organic pigment, a binder resin and a solvent, This is a method of forming a charge generation layer on a conductive support by pulling up. The vapor deposition method is a method in which a heat-vaporized organic pigment is deposited on a conductive support, and a charge transport layer is formed directly on the deposited film, or in an organic solvent solution or its vapor before the charge transport layer is formed. Is subjected to crystal transformation to form a predetermined charge generation layer. This vapor deposition method can form a uniform film at the molecular level and can be said to be a production method suitable for high-resolution and high-quality electrophotographic apparatuses.

In addition, a method of forming an intermediate layer of polyvinyl butyral resin has been proposed for the purpose of preventing the charge generating material from being dissolved in the charge transport layer coating (see, for example, Patent Document 1).
JP-A-11-84692

  However, when a charge generation layer is formed by a vapor deposition method compared to a coating method using a charge generation material and a resin dispersion paint on a conductive support, characteristic fluctuations due to the environment such as high temperature and high humidity and low temperature and low humidity are large. . Further, since the resin component is not contained, the adhesion with the support is poor and the photosensitive layer is easily peeled off. Specifically, in an electrophotographic apparatus, there is a problem that scratches due to contact between the developing roller and the spacer portion that keeps the distance between the photosensitive members constant are enlarged, and the photosensitive layer in the vicinity thereof is peeled off.

  As a solution to these problems, an adhesive layer made of a resin component such as a vinyl acetate resin or a vinyl chloride-vinyl acetate copolymer may be provided between the support and the charge generation layer. At present, it is not possible to achieve both adhesion and characteristics. In addition, even when the method for forming an intermediate layer of polyvinyl butyral resin is used for the purpose of preventing the charge generating material from dissolving into the above-mentioned charge transport layer coating material, the adhesion between the photosensitive layer and the support is sufficiently satisfied. It has not been done.

  The present invention has been made in view of such problems, and is a problem of an electrophotographic photoreceptor in which the charge generation layer is formed of a vapor deposition film of an organic pigment, that is, variation in potential characteristics at high temperature and high humidity or low temperature and low humidity. An object of the present invention is to solve a decrease in adhesion between the photosensitive layer and the support.

  Specifically, it has excellent environmental stability, high adhesiveness, high sensitivity to semiconductor laser light, and sensitivity and chargeability, and excellent repetitive stability of these photoreceptor characteristics. It aims at providing a body and its manufacturing method.

  It is another object of the present invention to provide an image forming apparatus and a process cartridge that can obtain a stable image under any environment by using the electrophotographic photoreceptor.

The present invention relates to an electrophotographic photoreceptor in which at least a charge generation layer, an intermediate layer, and a charge transport layer are laminated in this order on a conductive support , wherein the charge generation layer excludes both ends of the conductive support. a deposited film of only the organic pigment provided in the area in need of electrophotographic characteristics, the intermediate layer is acetalized with polyvinyl alcohol butyraldehyde provided on the entire said conductive support resin (I) The coating film mainly comprises a mixture with a resin (II) acetalized with an aldehyde other than butyraldehyde , and further contains at least a charge transport material and a binder resin in the same region as the coating region of the intermediate layer. The charge transport layer is provided.

  The function of the intermediate layer is determined by a resin obtained by acetalizing polyvinyl alcohol. The configuration is represented by the general formula (Formula 1). The ratio of l, m, and n in the general formula is determined by the degree of saponification of polyvinyl acetate, the degree of butyralization or acetalization of polyvinyl alcohol.

一般的に低ブチラール・アセタール化で低分子量の樹脂は接着性に優れている。ブチルアルデヒドにてアセタール化した樹脂を中間層に用いると、高温高湿又は低温低湿環境下における電位変動等の環境安定性が向上するが、電荷輸送層との接着性が低下する。しかしながら、ブチルアルデヒド以外のアルデヒドにてアセタール化した樹脂を混合すると、電荷輸送層との接着性が向上し、高温高湿又は低温低湿環境化における電位変動等の環境安定性も満足するものとなる。

Generally, low butyral and acetalized low molecular weight resins are excellent in adhesion. When a resin acetalized with butyraldehyde is used for the intermediate layer, environmental stability such as potential fluctuation in a high-temperature, high-humidity or low-temperature, low-humidity environment is improved, but adhesion to the charge transport layer is reduced. However, when an acetalized resin other than butyraldehyde is mixed, adhesion with the charge transport layer is improved, and environmental stability such as potential fluctuation in high temperature and high humidity or low temperature and low humidity environment is also satisfied. .

  In particular, the charge generation layer is not formed on the conductive support, and the portion where the charge transport layer is formed on the intermediate layer made of such a resin component is in close contact with the conductive support of the charge transport layer. The nature is further improved.

  As described above, according to the present invention, the environmental stability is excellent, the adhesiveness is high, the sensitivity to the semiconductor laser light is high, and the sensitivity, the charging property, and the repetitive stability of these photoconductor characteristics are improved. In addition, an excellent electrophotographic photoreceptor and a method for producing the same can be provided.

  Further, by using the electrophotographic photoreceptor, it is possible to provide an image forming apparatus and a process cartridge capable of obtaining a stable image under any environment.

The electrophotographic photoreceptor according to the first aspect of the present invention is the electrophotographic photoreceptor in which at least a charge generation layer, an intermediate layer, and a charge transport layer are laminated in this order on a conductive support. layer is deposited film of an organic pigment provided only in a necessary region of the electrophotographic characteristics except for the both end portions of the conductive support, a polyvinyl alcohol wherein the intermediate layer is provided on the entire said conductive support A coating film mainly comprising a mixture of a resin (I) acetalized with butyraldehyde and a resin (II) acetalized with an aldehyde other than butyraldehyde , and the same region as the coating region of the intermediate layer The charge transport layer including at least a charge transport material and a binder resin is provided.

  According to this configuration, the charge generation layer is provided only in a region requiring electrophotographic characteristics, while the charge generation layer is provided by providing the intermediate layer and the charge transport layer mainly composed of a resin over the entire conductive support. The adhesion of the charge transport layer to the conductive support can be improved in a region where no is provided.

Further , according to this configuration, on the charge generation layer formed of a vapor deposition film of an organic pigment, a resin (I) obtained by acetalizing polyvinyl alcohol with butyraldehyde and a resin acetalized with an aldehyde other than butyraldehyde (II) ) Is formed, the effect of improving the adhesion of the charge transport layer to the conductive support in the region where the charge generation layer is not provided is obtained, and the adhesion to the charge transport layer is improved. However, environmental stability such as potential fluctuation in high temperature and high humidity or low temperature and low humidity environment can also be improved. As a result, it is possible to realize an electrophotographic photoreceptor excellent in environmental stability and excellent in adhesiveness with a conductive support.

The method for producing an electrophotographic photoreceptor according to the second aspect of the present invention is the production of an electrophotographic photoreceptor in which at least a charge generation layer, an intermediate layer, and a charge transport layer are laminated in this order on a conductive support. in the method, a step of forming the charge generating layer by depositing an organic pigment only in a necessary region of the electrophotographic characteristics except for the both end portions of the conductive support, the polyvinyl alcohol onto the entire said conductive support and forming the intermediate layer by using a coating based on a mixture of the acetalization at butyraldehyde resin (I) and acetalized resin in aldehyde other than butyraldehyde (II), the intermediate layer Forming the charge transport layer including at least a charge transport material and a binder resin in the same region as the coating region.

  According to this method, the charge generation layer is provided only in a region requiring electrophotographic characteristics, while the charge generation layer is provided by providing an intermediate layer and a charge transport layer mainly composed of a resin on the entire conductive support. It is possible to produce an electrophotographic photoreceptor in which the adhesion of the charge transport layer to the conductive support is improved in a region where no is provided.

Further , according to this method, a resin (I) obtained by acetalizing polyvinyl alcohol with butyraldehyde and a resin acetalized with an aldehyde other than butyraldehyde (II) ) Is formed, the effect of improving the adhesion of the charge transport layer to the conductive support in the region where the charge generation layer is not provided is obtained, and the adhesion to the charge transport layer is improved. However, environmental stability such as potential fluctuation in high temperature and high humidity or low temperature and low humidity environment can also be improved. As a result, an electrophotographic photoreceptor excellent in environmental stability and adhesiveness to a conductive support can be produced.

The image forming apparatus according to the third aspect of the present invention, using an electrophotographic photosensitive member, a charging, image exposure, development, transfer and separation, in an image forming apparatus for forming an image through the cleaning process, the first aspect The construction using the electrophotographic photosensitive member is adopted.

  According to this configuration, in the image forming apparatus, the effect exhibited by the electrophotographic photoreceptor of any of the first and second aspects can be obtained. As a result, it is possible to realize an image forming apparatus capable of obtaining a stable image under any environment.

According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the member that holds the gap between the electrophotographic photosensitive member and the developing roller used in the developing step is the electrophotographic photosensitive member. The structure which contacts in the outermost surface layer is taken.

  According to this configuration, since the member for maintaining the distance between the electrophotographic photosensitive member and the developing roller is brought into contact with the outermost surface layer of the electrophotographic photosensitive member, the electrophotographic photosensitive member and the developing roller can be configured with a simple configuration. Can be maintained at a constant interval, and there is no need to provide a separate mechanism for maintaining the interval between the electrophotographic photosensitive member and the developing roller at a constant interval.

  Note that when the member is brought into contact with the outermost surface layer of the electrophotographic photoreceptor, peeling of the surface layer of the electrophotographic photoreceptor may occur as a problem. Since the adhesion of each layer is enhanced by using the electrophotographic photoreceptor of any one of the two aspects, the occurrence of such a problem can be reduced.

A process cartridge according to a fifth aspect of the present invention is a process cartridge used for an image forming apparatus that uses an electrophotographic photoreceptor and performs image formation through charging, image exposure, development, transfer / separation, and cleaning processes. The electrophotographic photosensitive member according to the first aspect is combined with any one of a charging unit, an image exposure unit, a developing unit, a transfer or separation unit, and a cleaning unit.

  According to this configuration, in the process cartridge used in the image forming apparatus, it is possible to obtain the effect exhibited by the electrophotographic photosensitive member according to any one of the first and second aspects. As a result, a process cartridge capable of obtaining a stable image under any environment can be realized.

According to a sixth aspect of the present invention, in the process cartridge according to the fifth aspect, the member that holds the gap between the electrophotographic photosensitive member and the developing roller of the developing unit is the outermost surface layer of the electrophotographic photosensitive member. The structure which contacts with is taken.

  According to this configuration, since the member for maintaining the distance between the electrophotographic photosensitive member and the developing roller is brought into contact with the outermost surface layer of the electrophotographic photosensitive member, the electrophotographic photosensitive member and the developing roller can be configured with a simple configuration. Can be maintained at a constant interval, and there is no need to provide a separate mechanism for maintaining the interval between the electrophotographic photosensitive member and the developing roller at a constant interval.

  When the member is brought into contact with the outermost surface layer of the electrophotographic photoreceptor, peeling of the surface layer of the electrophotographic photoreceptor may occur as a problem, but in the process cartridge, the first, Since the adhesion of each layer is enhanced using the electrophotographic photosensitive member according to any one of aspects 2, occurrence of such a problem can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view schematically showing the configuration of the electrophotographic photoreceptor according to the first exemplary embodiment of the present invention. In FIG. 1, an electrophotographic photoreceptor 10 is formed by laminating a charge generation layer 12, an intermediate layer 13, and a charge transport layer 14 on a conductive support 11.

  The conductive support 11 may have any conventionally known conductivity, such as a tube (cylindrical) made of a metal material such as aluminum, a plate, a sheet-like support, plastic or paper. A tube, a plate, a sheet-like support, or the like obtained by depositing a metal material on a tube, plate, or sheet-like support or imparting conductivity by a conductive paint, or molding a conductive plastic is used.

  In particular, a tube obtained by machining an aluminum alloy or a sheet obtained by evaporating aluminum on a polyethylene terephthalate film is often used. In the case where an aluminum tube is used for the conductive support 11, the surface of the support can be purified by cleaning with a surfactant or an organic solvent or by glow discharge treatment in a vacuum before forming the charge generation layer 12. is necessary. Inadequate cleaning of the aluminum tube causes an image defect resulting from an electrical failure due to the attached metal cutting powder, and a decrease in adhesiveness, which is a problem in the present invention.

The charge generation layer 12 formed on the conductive support 11 uses an organic pigment as a charge generation material, and has a pressure of 6 × 10 ⁻³ Pa or less by a resistance heating deposition method of 0.03 to 0.5 μm. It is obtained by forming a thin film in the range of On an aluminum tube having a length of 254 mm and an outer diameter of 30 mm, the amount of adhesion per one is approximately 1 to 10 mg.

  As the organic pigment, phthalocyanine pigments, perylene pigments, anthraquinone pigments, squarylium pigments and the like can be used. Of these, phthalocyanine pigments are preferred, and oxotitanium phthalocyanine is particularly used. These organic pigments are obtained by washing a crude pigment obtained by a known synthesis method into a highly crystalline pigment, or by sublimating and purifying it.

  The vapor deposition apparatus for vapor-depositing the organic pigment is not particularly limited as long as it can form a film uniformly on the entire conductive support 11, and if the conductive support 11 is an aluminum tube, an apparatus as shown in FIG. Used. FIG. 2 is a schematic view showing the inside of the chamber 21 of the vapor deposition apparatus.

In the vapor deposition apparatus shown in FIG. 2, an aluminum tube 22 mounted inside the chamber 21 revolves around the chamber 21 and forms a film on the upper part of the vapor deposition source 23. An oil diffusion pump or the like is attached to the exhaust port 24 to achieve a pressure of 6 × 10 ⁻³ Pa or less (unit). The vapor deposition source 23 may be a metal having a melting point equal to or higher than the sublimation point (about 500 ° C.) of the organic pigment to be vapor deposited, and a high melting point metal such as tungsten, molybdenum, tantalum, niobium, or an alloy thereof is often used.

  Furthermore, the vapor deposition source 23 is heated by applying a current from a DC power source, the organic pigment 20 filled in the vapor deposition source 23 is sublimated, and deposited on the aluminum tube 22 which is a conductive support to obtain a predetermined film thickness. It is. If the film thickness is less than or equal to the predetermined film thickness, the sensitivity required for the photoconductor cannot be obtained, and if it is greater than the predetermined film thickness, the chargeability necessary for the photoconductor cannot be obtained.

  The organic pigment vapor-deposited film thus formed is in an amorphous state and can be crystallized by being exposed to the vapor of an organic solvent or immersed in an organic solvent. Of course, it is also possible to transform the crystal by immersing it in the paint when forming the intermediate layer or the charge transport layer.

  After forming the charge generation layer 12 on the conductive support 11, the intermediate layer 13 is made of a resin (I) obtained by acetalizing polyvinyl alcohol with butyraldehyde and a resin (II) obtained by acetalization with an aldehyde other than butyraldehyde. Is formed on the charge generation layer 12. At this time, the intermediate layer coating material composed of the above-described resin and organic solvent is used and formed on the charge generation layer 12 by a known coating means such as a dip coating method.

The resin (I) obtained by acetalizing polyvinyl alcohol with butyraldehyde is represented by the general formula (Chemical Formula 2), and preferably has a molecular weight of 1 × 10 ⁴ to 15 × 10 ⁴ and a butyralization degree of 50% or more. . Similarly, a resin (II) obtained by acetalizing polyvinyl alcohol with an aldehyde other than butyraldehyde is represented by a general formula (Chemical Formula 3: R (i) is a methyl group CH ₃ ), and has a molecular weight of 1 × Those having a concentration of 10 ⁴ to 15 × 10 ⁴ and a butyral degree of 50% or more are preferable.

  As for the ratio of these resin (I) and resin (II), it is preferable that 10 to 50% of resin (II) is contained with respect to the whole quantity. If the resin (II) is not included, the adhesion with the charge transport layer is lowered. On the other hand, when the amount of the resin (II) is large, the variation in electrophotographic characteristics in a high temperature and high humidity and low temperature and low humidity environment increases.

  Furthermore, organic solvents such as alcohols, ethylene glycol derivatives, ketones, and aromatic hydrocarbons can be used as the organic solvent that dissolves the resin in order to adjust the coating for the intermediate layer. The solvent is selected according to the required crystal state of the deposited organic pigment, and the resin concentration is adjusted to 1 to 5% in order to form a predetermined amount on the charge generation layer. When the amount is less than 1 part by weight based on 1 part by weight of the organic pigment deposited on the charge generation layer, a difference occurs in electrophotographic characteristics under high temperature and high humidity and low temperature and low humidity environments, in particular, the post-exposure potential. On the other hand, if it exceeds 2 parts by weight, the post-exposure potential increases due to repeated printing.

  Further, an intermediate layer is formed by a dip coating apparatus 31 as shown in FIG. Specifically, a pot 32 provided with a circulation pump 35 and a filter unit 36 is filled with an intermediate layer coating material 30, and an aluminum tube 33 which is a conductive support on which a charge generating material is deposited is provided with a gripping device. The movable part 34 is attached and dip coating is performed by moving the movable part up and down.

  The pulling rate is adjusted to 10 to 300 mm / min so that a predetermined amount of intermediate layer can be formed. Further, depending on the state of the organic pigment, it can be formed by a spray coating method. Finally, after coating, the intermediate layer is formed by natural drying or heat drying.

  After the charge generation layer 12 and the intermediate layer 13 are thus formed on the conductive support 11, the charge transport layer 14 made of the charge transport material and the binder resin is made of the charge transport material, the binder resin, and the organic solvent. The charge transport layer coating material is laminated on the intermediate layer 13 by a known coating means such as a dip coating method.

  As the charge transport material, an electron-donating oxazole compound, oxadiazole compound, pyrazoline compound, hydrazone compound, stilbene compound, tetraphenylbutadiene compound, biphenyl compound, and derivatives of these compounds can be used. Moreover, these compounds can also be used in mixture of 2 or more types.

  As the binder resin, resins such as polyester, polycarbonate, polysulfone, polyarylate, and polymethyl methacrylate can be used. However, compatibility with charge transport materials, film strength, solubility in coating solvents, and stability as a coating material. From the viewpoint of properties, polycarbonate is preferred.

  The composition ratio of these binder resins to the charge transport material is in the range of 0.25 to 3 with respect to the binder resin 1 by weight. In addition to the charge transport material and the binder resin, an antioxidant, an ultraviolet absorber and the like can be added to prevent the deterioration of these materials.

  Furthermore, organic solvents for dissolving these charge transport materials and binder resins to form charge transport layer coatings include chlorinated hydrocarbons such as dichloromethane and chloroform, cyclic ethers such as dioxane and tetrahydrofuran, toluene Aromatic hydrocarbons such as xylene are used. These organic solvents can be used singly or in combination of two or more, and are used by adjusting the concentration of the non-volatile content in the charge transport layer coating material in the range of 10 to 40% by weight.

  In general, the charge transport layer 14 is formed by a dip coating apparatus 41 as shown in FIG. 4 using the thus prepared charge transport layer coating material. Specifically, an aluminum tube 43 that is a conductive support on which the charge generation layer 12 and the intermediate layer 13 are formed is mounted on a movable portion 44 provided with a gripping device, and the charge transport layer coating 40 is placed in the container. After being immersed in the pot 42, the charge transport layer is formed by pulling up at a predetermined speed. The pot 42 is provided with a circulation pump 45 and a filter unit 46. After the dip coating, the organic solvent component is volatilized by a hot air dryer or the like, and a charge transport layer having a thickness of about 5 to 40 μm is formed after drying.

  As described above, according to the electrophotographic photoreceptor 10 of the first embodiment, the resin (I) obtained by acetalizing polyvinyl alcohol with butyraldehyde on the charge generation layer 12 formed of a vapor deposition film of an organic pigment, and butyraldehyde By forming the intermediate layer 13 composed of the resin (II) acetalized with an aldehyde other than the above, it is possible to improve the adhesiveness with the charge transport layer 14 and to change the potential in a high temperature / high humidity or low temperature / low humidity environment. Environmental stability can also be improved. As a result, it is possible to realize an electrophotographic photoreceptor excellent in environmental stability and excellent in adhesiveness with a conductive support.

(Embodiment 2)
While the electrophotographic photoreceptor according to the first exemplary embodiment of the present invention forms the charge generation layer in the entire region of the conductive support, the electrophotographic photosensitive member according to the second exemplary embodiment includes the photoconductor. The difference is that the charge generation layer is formed only in a region requiring electrophotographic characteristics.

  FIG. 5 schematically shows the configuration of the electrophotographic photoreceptor according to the second exemplary embodiment of the present invention. In FIG. 5, as an example, a surface view schematically showing the structure of an electrophotographic photoreceptor formed on a cylindrical aluminum tube on the upper side (hereinafter referred to as “cylindrical electrophotographic photoreceptor”) is shown. A sectional view schematically showing the configuration of a cylindrical electrophotographic photoreceptor is shown below.

  In FIG. 5, a cylindrical electrophotographic photoreceptor 50 is formed by laminating a charge generation layer 52, an intermediate layer 53, and a charge transport layer 54 in this order on a conductive support 51, as in FIG. is there. Each configuration is the same as that shown in FIG. 1, but the electrophotographic photoreceptor 50 according to Embodiment 2 has a configuration in which a charge generation layer is formed only in a region 55 that requires electrophotographic characteristics of the photoreceptor. It has become.

  Specifically, in the vapor deposition apparatus of FIG. 2, the charge generation layer 52 is formed by attaching a shielding plate so that the organic pigment does not adhere to both ends of the conductive support 51. Thereby, it can prevent that an organic pigment adheres to the both ends of the electroconductive support body 51 which is a part which does not require electrophotographic characteristics. Further, the intermediate layer 53 and the charge transport layer 54 are sequentially laminated on the entire region of the conductive support 51 on which the charge generation layer 52 is formed, thereby completing the cylindrical electrophotographic photoreceptor 50.

  As described above, according to the cylindrical electrophotographic photoreceptor 50 of the second embodiment, the charge generation layer 52 is formed only in the region requiring the electrophotographic characteristics, while the resin is mainly applied to the entire area on the conductive support 51. By forming the intermediate layer 53 and the charge transport layer 54 as components, it is possible to improve the adhesion of the charge transport layer 54 to the conductive support 51 in a region where the charge generation layer 52 is not formed.

  Also in the second embodiment, as in the first embodiment, a resin (I) obtained by acetalizing polyvinyl alcohol with butyraldehyde and acetalized with an aldehyde other than butyraldehyde on the charge generation layer 52. By forming the intermediate layer 53 made of the resin (II), the adhesiveness with the charge transport layer 54 is improved, and the environmental stability such as potential fluctuation in a high temperature and high humidity or low temperature and low humidity environment is improved. Can do. As a result, it is possible to realize an electrophotographic photoreceptor excellent in environmental stability and excellent in adhesiveness with a conductive support.

  FIG. 6 is a cross-sectional view showing a schematic configuration of an image forming apparatus equipped with electrophotographic photoreceptors 10 and 50 according to Embodiments 1 and 2 of the present invention.

  The image forming apparatus shown in FIG. 1 includes a reading unit 602 that scans a document and reads an image on the top of a housing 601, and an upper cover 603 that opens and closes the document reading surface is attached to the upper surface of the reading unit 602 so as to be freely opened and closed. ing.

  A discharge space 604 for discharging recording paper is formed in the lower portion of the reading unit 602 in the housing 601, and the lower surface of the discharge space 604 functions as a discharge tray 605. In addition, a paper feed cassette 606 that stores recording paper is disposed at the bottom of the housing 601.

  A pickup roller 607 is disposed above and below the sheet feeding side end of the sheet feeding cassette 606 so as to be movable up and down, and a sheet feeding roller 608 and a separation roller 609 are disposed opposite to each other in the vicinity of the pickup roller 607. The paper feed roller 608 is a roller for feeding the recording paper taken out from the paper feed cassette 606 by the pickup roller 607 to the transport path, and the separation roller 609 is a plurality of sheets taken out from the paper feed cassette 606 in an overlapping manner. A roller for separating one sheet from a recording sheet.

  A recording paper conveyance path is formed substantially vertically upward from the lower portion of the housing 601. The electrophotographic photoreceptor 10 (50) according to the present invention is disposed on the conveyance path. A registration roller 610 for controlling the conveyance timing of the recording paper passing through the electrophotographic photoreceptor 10 (50) is disposed near the entrance of the conveyance path. The electrophotographic photoreceptor 10 (50) is held by a process cartridge 611. A laser scan unit (LSU) 612 is disposed inside the apparatus with respect to the process cartridge 611. The LSU 612 forms a latent image on the electrophotographic photoreceptor 10 (50). Further, a transfer roller 613 is disposed opposite to the electrophotographic photoreceptor 10 (50), and the transfer roller 613 transfers the toner attached to the electrophotographic photoreceptor 10 (50) onto a recording sheet.

  A fixing unit 614 is installed on the downstream side of the process cartridge 611 in the recording paper conveyance path. The fixing unit 614 includes a fixing roller 615 and a pressure roller 616 that is pressed against the fixing roller 615 with a predetermined pressure. The recording paper fed from the fixing roller 615 and the pressure roller 616 is discharged to the paper discharge tray 605 by a discharge roller 617 provided on the discharge space 604 side of the fixing unit 614.

  FIG. 7 is an enlarged schematic sectional view of the process cartridge 611 holding the electrophotographic photoreceptor 10 (50) according to the present invention.

  In the process cartridge 611, the electrophotographic photoreceptor 10 (50) is grounded through a rotating shaft and is driven to rotate counterclockwise as indicated by an arrow in the figure. The electrophotographic photoreceptor 10 (50) is charged by the charging roller 702 of the charging unit 701. Specifically, the charging roller 702 superimposes a DC bias or an AC bias to give a uniform charge on the electrophotographic photoreceptor 10 (50).

  After the electrophotographic photoreceptor 10 (50) is uniformly charged, image exposure based on the image signal from the LSU 612 is performed. The light source used for the LSU 612 is a semiconductor laser, and laser light is scanned on the electrophotographic photoreceptor 10 (50) by an optical system such as a polygon mirror and an fθ lens, and photoelectric conversion of the electrophotographic photoreceptor 10 (50) is performed. An electrostatic latent image is formed on the electrophotographic photoreceptor 10 (50) by the function.

  Next, the electrostatic latent image is developed by the developing unit 703, and a toner image is formed on the electrophotographic photoreceptor 10 (50). Specifically, in the case of magnetic one-component toner, a toner layer regulated by a developing blade 706 is formed on a developing roller 705 containing a magnet 704, and the electrophotographic photoreceptor 10 (50), the developing roller 705, and the like. Development is performed with a DC bias or AC bias applied between the two. The developing roller 705 is driven to rotate clockwise as indicated by an arrow in the figure.

  The distance between the developing roller 705 and the electrophotographic photoreceptor 10 (50) is kept constant by a gap spacer 707 attached to the developing roller 705. The gap spacer 707 is attached to both ends of the circumferential surface of the developing roller 705 (ends on the back side and the near side shown in FIG. 7), and is the outermost surface layer (circumferential surface) of the electrophotographic photoreceptor 10 (50). Touch both ends. In particular, in the electrophotographic photoreceptor 50 according to the second embodiment, contact is made at a portion where the charge generation layer 52 is not formed.

  As described above, the gap spacer 707, which is a member for maintaining the distance between the electrophotographic photoreceptor 10 (50) and the developing roller 705, is brought into contact with the outermost surface layer of the electrophotographic photoreceptor 10 (50). With the configuration, the interval between the electrophotographic photoreceptor 10 (50) and the developing roller 705 can be maintained at a constant interval, and the interval between the electrophotographic photoreceptor 10 (50) and the developing roller 705 is maintained at a constant interval. There is no need to provide a separate mechanism.

  When the gap spacer 707 is brought into contact with the outermost surface layer of the electrophotographic photoreceptor 10 (50), peeling of the surface layer of the electrophotographic photoreceptor 10 (50) may occur as a problem. Since the image forming apparatus uses the electrophotographic photoreceptor 10 (50) in which the adhesion of each layer described above is improved, occurrence of such a problem can be reduced. In particular, when the electrophotographic photoreceptor 50 according to the second embodiment is used, the both ends of the electrophotographic photoreceptor 50 having improved adhesion come into contact with the gap spacer 707, and thus the occurrence of this problem. It can be further reduced.

  The toner image formed on the electrophotographic photoreceptor 10 (50) is transferred to the recording paper supplied from the paper feed cassette 606 by the transfer roller 613 described above. The recording paper on which the toner image is transferred is separated from the electrophotographic photoreceptor 10 (50) and sent to the fixing unit 614. After the toner image is heated and fixed on the recording paper by the fixing unit 614, the recording paper is discharged to the paper discharge tray 605.

  On the other hand, in the electrophotographic photoreceptor 10 (50), residual toner is removed by pressure contact of the cleaning blade 709 of the cleaning unit 708, and the surface is cleaned, and the process returns to the charging unit 701 for the next image forming process. enter.

  As is apparent from the above description, the process cartridge 611 shown in FIG. 7 includes the electrophotographic photoreceptor 10 (50), the charging unit 701 having the charging roller 702, the developing unit 703 having the developing roller 705, and the cleaning blade. The cleaning unit 708 having the 709 is integrally provided. However, the present invention is not limited to the case where all of these functions are provided, and the process cartridge 611 may be configured by combining some of these functions.

  Hereinafter, specific examples and comparative examples of the electrophotographic photoreceptor according to the embodiment of the present invention will be described.

Example 1
An aluminum (aluminum-magnesium-silicon alloy) cutting tube having an outer diameter of 30 mm, an inner diameter of 28.5 mm, and a length of 254 mm was washed with a degreasing detergent (Clean Through LC870 manufactured by Kao Corporation) and ion-exchanged water. It attaches to the vapor deposition equipment. An oxotitanium phthalocyanine vapor deposition film was formed on the aluminum tube under a reduced pressure of 5 × 10 ⁻³ Pa. The amount of oxotitanium phthalocyanine per aluminum tube was 2 mg.

  Next, 2 parts by weight of resin (I) (Sekisui Chemical Co., Ltd., ESREC BL-1) obtained by acetalizing polyvinyl alcohol with butyraldehyde with respect to 100 parts by weight of ethanol (first grade reagent manufactured by Kanto Chemical Co., Ltd.) The aluminum tube in which the vapor-deposited film was formed in a solution in which 0.5 part by weight of resin (II) (Sekisui Chemical Co., Ltd. S-REC BX-1) acetalized with an aldehyde other than butyraldehyde was added is shown in FIG. The intermediate layer is dip coated with a dip treatment apparatus. The amount of resin per aluminum tube in the intermediate layer was 3 mg. That is, the amount is 1.5 times the amount of 2 mg of oxotitanium phthalocyanine which is the organic pigment vapor deposition film of the charge generation layer. Subsequently, 18 parts by weight of 2-methyl-4-dibenzylaminobenzaldehyde-N, N-diphenylhydrazone and 2 parts by weight of 1,1-bis (p-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene, Using a paint composed of 20 parts by weight of polycarbonate (Tufzette P-300 manufactured by Idemitsu Kosan Co., Ltd.) and 100 parts by weight of dichloromethane, a charge transport layer is provided so that the film thickness after drying is 25 μm in the dip coating apparatus of FIG. The photoreceptor was completed.

  Evaluation is performed by attaching the obtained photoreceptor to a process cartridge of Panafax UF770 manufactured by Matsushita Electric Power Systems Co., Ltd., attaching a surface potential meter (MODEL 344 manufactured by Trek) to the developing portion, and charging potential V0 and exposure at the position of the developer. The post potential VL was measured. The results of this potential measurement are shown in Table 1. The same measurement was also performed under a high temperature and high humidity environment (35 ° C. and 70%) and a low temperature and low humidity environment (10 ° C. and 15%). Further, the photosensitive layer peels off (gap part peeling) at the gap spacer 707 that keeps the distance from the developing roller 705 in the low temperature and low humidity environment, and the potential measurement result after repeated printing of 8000 sheets (characteristic after printing 8000 sheets). Table 1 also shows the number of printed pages.

(Example 2)
In Example 2, a photoconductor was prepared and evaluated in the same manner as in Example 1 except that 2.25 parts by weight of resin (I) and 0.25 parts by weight of resin (II) in Example 1 were used. . The results are shown in Table 1.

(Example 3)
In Example 3, a photoconductor was prepared and evaluated in the same manner as in Example 1 except that the resin (I) in Example 1 was changed to 1.25 parts by weight and the resin (II) was changed to 1.25 parts by weight. . The results are shown in Table 1.

Example 4
In Example 4, the photoconductor was prepared in the same manner as in Example 1 except that the resin concentration of the intermediate layer paint was 1.8% and the resin amount per aluminum tube of the intermediate layer in Example 1 was 2 mg. Created and evaluated. That is, this is the case where the amount of resin in the intermediate layer is the same as the amount of oxotitanium phthalocyanine 2 mg that is the organic pigment vapor deposition film of the charge generation layer. The results are shown in Table 1.

(Example 5)
In Example 5, a photoconductor was prepared in the same manner as in Example 1 except that the resin concentration of the intermediate layer coating was 3% and the resin amount per aluminum tube of the intermediate layer in Example 1 was 4 mg. Evaluation was performed. This is a case where the amount of resin in the intermediate layer is twice the amount of 2 mg of oxotitanium phthalocyanine which is the organic pigment vapor deposition film of the charge generation layer. The results are shown in Table 1.

(Example 6)
In Example 6, when forming the oxotitanium phthalocyanine vapor deposition film, a shielding plate was provided inside the vapor deposition apparatus so that the vapor deposition film did not adhere to both end portions 10 mm of the aluminum tube. Other than that, a photoconductor was prepared and evaluated in the same manner as in Example 1. That is, the evaluation was performed using the electrophotographic photoreceptor 50 according to the second embodiment. The results are shown in Table 1. Here, as shown in Table 1, good results could be obtained particularly in the evaluation of gap part peeling.

(Comparative Example 1)
In Comparative Example 1, a photoreceptor was prepared and evaluated in the same manner as in Example 1 except that the intermediate layer in Example 1 was not provided. The results are shown in Table 1. Here, as shown in Table 1, it can be seen that there are particularly large fluctuations in environmental fluctuations and repeated fluctuations. In the evaluation of gap peeling, it can be recognized that the film strength of the photosensitive layer is insufficient.

(Comparative Example 2)
In Comparative Example 2, a photoreceptor was prepared and evaluated in the same manner as in Example 1 except that 2.5 parts by weight of the resin (I) in Example 1 was not used and the resin (II) was not used. The results are shown in Table 1. Here, it can be recognized that the film strength of the photosensitive layer is insufficient in the evaluation of the peeling of the gap compared to the evaluation of Example 1 or the like.

(Comparative Example 3)
In Comparative Example 3, a photoreceptor was prepared and evaluated in the same manner as in Example 1 except that 2.5 parts by weight of the resin (II) in Example 1 was not used. The results are shown in Table 1. Here, although some improvement is seen in the evaluation of the gap peeling, it can be seen that there are large fluctuations in environmental fluctuations and repeated fluctuations, particularly in high temperature and high humidity.

(Comparative Example 4)
In Comparative Example 4, a photoconductor was prepared in the same manner as in Example 1 except that the resin content concentration of the intermediate layer paint was 5% and the resin amount per aluminum tube of the intermediate layer in Example 1 was 7 mg. Evaluation was performed. This is a case where the amount of resin in the intermediate layer is 3.5 times the amount of 2 mg of oxotitanium phthalocyanine which is the organic pigment vapor deposition film of the charge generation layer. The results are shown in Table 1. Here, it can be seen that there are large fluctuations in environmental fluctuations and repetitive fluctuations, particularly in high temperature and high humidity.

表１に示す結果から明らかなように、本実施の形態に係る電子写真用感光体では、良好な電子写真特性を示すとともに、環境変動、繰り返し変動が小さく、感光層の膜強度も優れた性能を示す。特に、上記実施例では、中間層を形成しない場合（比較例１）、中間層の樹脂量を、電荷発生層の有機顔料蒸着膜であるオキソチタニウムフタロシアニン量２ｍｇと同量にした場合（実施例４）、オキソチタニウムフタロシアニン量２ｍｇの１．５倍にした場合（実施例１）、２倍にした場合（実施例５）及び３．５倍にした場合（比較例４）について評価を行っている。この評価結果から中間層の樹脂量は、電荷発生層の有機顔料蒸着膜の質量の０．５〜３倍の量とした場合に良好な電子写真特性を示すとともに、環境変動、繰り返し変動が小さく、感光層の膜強度も優れた性能を示すことが認識できる。

As is apparent from the results shown in Table 1, the electrophotographic photoreceptor according to the present embodiment has good electrophotographic characteristics, small environmental fluctuations, small fluctuations, and excellent film strength of the photosensitive layer. Indicates. In particular, in the above example, when the intermediate layer is not formed (Comparative Example 1), the amount of resin in the intermediate layer is the same as 2 mg of oxotitanium phthalocyanine which is the organic pigment deposited film of the charge generation layer (Example) 4) In the case of 1.5 times the amount of oxotitanium phthalocyanine 2 mg (Example 1), the case of 2 times (Example 5) and the case of 3.5 times (Comparative Example 4) were evaluated. Yes. From this evaluation result, the resin amount of the intermediate layer shows good electrophotographic characteristics when the amount is 0.5 to 3 times the mass of the organic pigment vapor-deposited film of the charge generation layer, and the environmental variation and repetitive variation are small. It can be recognized that the film strength of the photosensitive layer also shows excellent performance.

  As described above, according to the present invention, the environmental stability is excellent, the adhesiveness is high, the sensitivity to the semiconductor laser light is high, and the sensitivity, the charging property, and the repetitive stability of these photoconductor characteristics are improved. In addition, it is possible to provide an excellent electrophotographic photoreceptor and a method for producing the same, and is useful for obtaining an image forming apparatus and a process cartridge capable of obtaining a stable image under any environment.

Sectional drawing which showed typically the structure of the electrophotographic photoreceptor which concerns on embodiment of this invention Schematic showing the configuration of the vapor deposition apparatus used in the examples of the present invention Schematic showing the configuration of the dip coating apparatus for forming an intermediate layer used in the examples of the present invention Schematic showing the configuration of the dip coating apparatus for forming a charge transport layer used in the examples of the present invention Sectional drawing which showed typically the structure of the electrophotographic photoreceptor which concerns on embodiment of this invention 1 is a cross-sectional view of an image forming apparatus equipped with an electrophotographic photoreceptor according to an embodiment of the present invention. Sectional drawing of the process unit carrying the electrophotographic photoreceptor which concerns on embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electrophotographic photoreceptor 11 Conductive support 12 Charge generation layer 13 Intermediate layer 14 Charge transport layer 20 Organic pigment (charge generation material (oxotitanium phthalocyanine))
21 Vapor deposition chamber 22 Aluminum tube (conductive support)
DESCRIPTION OF SYMBOLS 23 Deposition source 24 Exhaust port 30 Paint for intermediate | middle layer 31 Immersion coating apparatus 32 Pot 33 Aluminum pipe | tube (conductive support body in which the charge generating material was vapor-deposited)
34 Movable part provided with gripping device 35 Circulating pump 36 Filter unit 40 Paint for charge transport layer 41 Immersion coating device 42 Pot 43 Aluminum tube (conductive support on which charge generation layer and intermediate layer are formed)
44 Movable part provided with gripping device 45 Circulating pump 46 Filter unit 50 Electrophotographic photosensitive member (cylindrical electrophotographic photosensitive member)
51 Conductive support (aluminum tube)
52 charge generation layer 53 intermediate layer 54 charge transport layer 55 region where electrophotographic characteristics are required 606 paper feed cassette 611 process cartridge 612 laser scan unit (LSU)
613 Transfer roller 614 Fixing unit 701 Charging unit 702 Charging roller 703 Developing unit 705 Developing roller 706 Developing blade 708 Cleaning unit 709 Cleaning blade

Claims (6)

In an electrophotographic photoreceptor in which at least a charge generation layer, an intermediate layer, and a charge transport layer are laminated in this order on a conductive support, the charge generation layer has electrophotographic characteristics excluding both ends of the conductive support . a deposited film of an organic pigment provided only in a necessary region, the intermediate layer is non-acetalized resin (I) and butyraldehyde polyvinyl alcohol provided on the entire area the conductive support at butyraldehyde A coating film comprising a mixture of a resin (II) acetalized with aldehyde as a main component, and the charge transport layer further comprising at least a charge transport material and a binder resin in the same region as the coating region of the intermediate layer; An electrophotographic photoreceptor characterized by being provided. In a method for producing an electrophotographic photosensitive member in which at least a charge generation layer, an intermediate layer, and a charge transport layer are laminated in this order on a conductive support, the electrophotographic characteristics excluding both ends of the conductive support are necessary. a step of forming the charge generating layer by depositing an organic pigment only in the region at acetalized resin (I) and butyraldehyde except aldehyde polyvinyl alcohol onto the entire said conductive support at butyraldehyde the charge transport comprising the step of forming the intermediate layer by using a coating based on a mixture of acetalized resin (II), and at least a charge-transporting substance and a binder resin in the same region and the intermediate layer coating region Forming a layer, and a method for producing an electrophotographic photoreceptor. An image forming apparatus that uses an electrophotographic photoreceptor and forms an image through charging, image exposure, development, transfer / separation, and a cleaning process, wherein the electrophotographic photoreceptor according to claim 1 is used. Image forming apparatus. 4. The image forming apparatus according to claim 3 , wherein a member for maintaining a distance between the electrophotographic photosensitive member and a developing roller used in a developing process is in contact with an outermost surface layer of the electrophotographic photosensitive member. A process cartridge for use in an image forming apparatus that uses an electrophotographic photoreceptor to form an image through charging, image exposure, development, transfer / separation, and cleaning steps, and the electrophotographic photoreceptor according to claim 1 ; A process cartridge produced by combining any one of a charging unit, an image exposure unit, a developing unit, a transfer or separation unit, and a cleaning unit. 6. The process cartridge according to claim 5 , wherein a member for maintaining a distance between the electrophotographic photosensitive member and a developing roller of the developing unit is in contact with the outermost surface layer of the electrophotographic photosensitive member.

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