JP2010211031A - Process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that is free of charging failure in an electrophotographic photoreceptor, suppresses image defects (image ghost) and stably gives images even in repeated use for a long period of time. <P>SOLUTION: The image forming apparatus includes an electrophotographic photoreceptor 7, a charging means 8, an electrostatic latent image forming means 9, a developing means 11, a transfer means 40, a potential irregularity eliminating means 15, and a toner removing means 13. The electrophotographic photoreceptor 7 includes a conductive substrate and a photosensitive layer formed on the surface of the conductive substrate; wherein the outermost surface layer of the photosensitive layer includes a crosslinked product using at least one selected from guanamine compounds and melamine compounds and at least one of specified charge transporting material; the content ratio of the guanamine compounds and melamine compounds in the outermost surface layer ranges from 0.1 mass% to 5 mass%; and the content ratio of the charge transporting material in the outermost surface layer ranges from 95 mass% to 99 mass%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a process cartridge and an image forming apparatus.

  An electrophotographic image forming apparatus generally has the following configuration and process. That is, the surface of the electrophotographic photosensitive member is charged to a polarity and a potential by a charging unit, and the electrostatic latent image is formed by selectively removing the surface of the charged electrophotographic photosensitive member by image exposure, and then developing unit. Then, the toner is attached to the electrostatic latent image to develop the latent image as a toner image, and the toner image is transferred to a transfer medium by a transfer unit to be discharged as an image formed product.

  In recent years, electrophotographic photoreceptors have the advantage of being able to obtain high speed and high printing quality, and thus have been remarkably used in the fields of copying machines and laser beam printers. As an electrophotographic photosensitive member used in these image forming apparatuses, it is inexpensive, manufacturable and disposable compared to conventional electrophotographic photosensitive members using inorganic photoconductive materials such as selenium, selenium-tellurium alloy, selenium-arsenic alloy, cadmium sulfide. Organic photoreceptors using organic photoconductive materials that have advantages in terms of the point have come to dominate.

  Conventionally, a corona charging method using a corona discharger has been used as the charging method. However, in recent years, a contact charging method having advantages such as low ozone and low power has been put into practical use and has been actively used. In the contact charging method, a conductive member as a charging member is brought into contact with or close to the surface of the photosensitive member, and a voltage is applied to the charging member to charge the surface of the photosensitive member. In addition, as a method of applying to the charging member, there are a direct current method in which only a direct current voltage is applied and an alternating current superposition method in which an alternating current voltage is superimposed on the direct current voltage. This contact charging method has the advantage that the apparatus can be downsized and the generation of gas such as ozone is small.

  As a transfer method, a method of directly transferring to paper has been the mainstream. However, in recent years, a method of transferring using an intermediate transfer member has been widely used because the degree of freedom of the transferred paper is widened.

  On the other hand, it is possible to suppress the deterioration and wear of the photoconductor by the contact charging method, and to prevent the photoconductor from being scratched or foreign matter pierced by the direct charging method or the use of the intermediate transfer body. In order to suppress the occurrence of a phenomenon in which a local excessive current flows), it has been proposed to improve the strength by providing a protective layer on the surface of the electrophotographic photosensitive member. As a material system for forming the protective layer, for example, Patent Document 1 proposes an alcohol-soluble charge transport material and a phenol resin.

  Patent Document 2 proposes a cured film of an alkyl etherified benzoguanamine / formaldehyde resin and an electron-accepting carboxylic acid or an electron-accepting polycarboxylic acid anhydride. Patent Document 3 discloses a cured film obtained by doping a benzoguanamine resin with iodine, an organic sulfonic acid compound, or ferric chloride, and Patent Document 4 includes a specific additive and a phenol resin, a melamine resin, a benzoguanamine resin, and a siloxane resin. Alternatively, a cured film with a urethane resin has been proposed. In addition, Patent Documents 5 and 6 also propose a cured film.

JP 2002-82469 A Japanese Patent Laid-Open No. 62-251757 Japanese Patent Laid-Open No. 7-146564 JP 2006-84711 A Japanese Patent No. 2575536 JP-A-9-190004

  An object of the present invention is to provide an image forming apparatus in which an electrophotographic photosensitive member does not cause poor charging even when used repeatedly over a long period of time, image defects (image ghosts) are suppressed, and images can be stably obtained. It is.

The above problems have been solved by the following means. That is,
The invention according to claim 1
Formed on the electrophotographic photosensitive member; an electrophotographic photosensitive member; a charging unit that charges the electrophotographic photosensitive member; an electrostatic latent image forming unit that forms an electrostatic latent image on the charged electrophotographic photosensitive member; Developing means for developing the electrostatic latent image to form a toner image; transfer means for transferring the toner image to the transfer target; and the potential of the electrophotographic photosensitive member surface after the toner image is transferred to the transfer target A potential unevenness removing means for removing unevenness; and a toner removing means for removing residual toner on the surface of the electrophotographic photosensitive member after the toner image is transferred to the transfer body,
The electrophotographic photoreceptor includes a conductive substrate and a photosensitive layer provided on the surface of the conductive substrate, and the outermost surface layer of the photosensitive layer is at least one selected from a guanamine compound and a melamine compound; , —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH, and at least one charge transporting material having at least one substituent selected from —COOH, and The content in the outermost surface layer of at least one kind selected from the guanamine compound and the melamine compound is 0.1% by mass or more and 5% by mass or less, and the content in the outermost surface layer of the charge transporting material Is 95% by mass or more and 99% by mass or less.

The invention according to claim 2
The image forming apparatus according to claim 1, wherein the charging unit is a non-contact type charging unit.

The invention according to claim 3
3. The image according to claim 1, wherein the potential unevenness removing unit is a non-contact charging member, and an AC voltage is superimposed on a DC voltage to apply the surface of the electrophotographic photosensitive member. Forming device.

The invention according to claim 4
The image forming apparatus according to any one of claims 1 to 3, wherein a peripheral speed when forming an image on the electrophotographic photosensitive member is 300 mm / sec or more and 340 mm / sec or less. .

The invention according to claim 5
The outermost surface layer of the photosensitive layer is at least one selected from guanamine compounds and melamine compounds, and at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. 5. The image forming apparatus according to claim 1, wherein at least one kind of charge transporting material having a high molecular weight is cured using an acid catalyst.

The invention according to claim 6
The image forming apparatus according to claim 5, wherein an amount of the acid catalyst with respect to 100 parts by mass of the compound having the guanamine structure or the melamine structure is 0.1 parts by mass or more and 50 parts by mass or less.

The invention according to claim 7 provides:
The image forming apparatus according to claim 1, wherein the charge transporting material is a compound represented by the following general formula (I).
_{F - ((- R 1 -X} ) n1 R 2 -Y) n2 (I)
(In general formula (I), F is an organic group derived from a compound having a hole transporting ability, R ₁ and R ₂ are each independently a linear or branched alkylene group having 1 to 5 carbon atoms. , N1 represents 0 or 1, n2 represents an integer of 1 to 4, X represents an oxygen, NH, or sulfur atom, Y represents —OH, —OCH ₃ , —NH ₂ , —SH, or — COOH is shown.)

The invention according to claim 8 provides:
8. The process cartridge according to claim 1, wherein at least the electrophotographic photosensitive member, the charging unit, the potential unevenness removing unit, and the toner removing unit are integrated into an image forming apparatus. The image forming apparatus according to any one of the above.

The invention according to claim 9 is:
Removes at least the electrophotographic photosensitive member, charging means for charging the electrophotographic photosensitive member, and uneven charging on the surface of the electrophotographic photosensitive member after the toner image is transferred to the transfer target. Potential unevenness removing means to perform, and toner removing means for removing residual toner on the surface of the electrophotographic photosensitive member after the toner image is transferred to the transfer target,
The electrophotographic photosensitive member has a conductive substrate and a photosensitive layer provided on the surface of the conductive substrate, and the outermost surface layer of the photosensitive layer is at least one selected from a guanamine compound and a melamine compound; , —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH, and at least one charge transporting material having at least one selected from a substituent as a substituent. The content in the outermost surface layer of at least one kind selected from the guanamine compound and the melamine compound is 0.1% by mass or more and 5% by mass or less, and the content in the outermost surface layer of the charge transporting material Is 95% by mass or more and 99% by mass or less.

According to the first aspect of the present invention, as compared with the case where the present configuration is not provided, even if it is repeatedly used over a long period of time, the electrophotographic photosensitive member is not charged poorly and image defects (image ghost) are suppressed. An image forming apparatus capable of stably obtaining an image is provided.
According to the invention which concerns on Claim 2, it drive | operates at high speed compared with the case where it does not have this structure.
According to the invention of claim 3, compared to the case without this configuration, even if it is repeatedly used over a long period of time, the electrophotographic photosensitive member does not fail to be charged and image defects (image ghost) are suppressed. The effect that a stable image can be obtained becomes remarkable.

According to the invention which concerns on Claim 4, compared with the case where it does not have this structure, it operates at high speed, without generating an image defect.
According to the invention which concerns on Claim 5, hardening of a charge transport material is accelerated | stimulated compared with the case where it does not have this structure.
According to the sixth aspect of the present invention, the effect that the curing of the charge transport material is promoted becomes remarkable as compared with the case where this configuration is not provided.

According to the invention of claim 7, the effect can be obtained over a longer period of time compared to the case where the present configuration is not provided.
According to the invention which concerns on Claim 8, operation becomes easy compared with the case where it does not have this structure.
According to the ninth aspect of the present invention, as compared with the case where the present configuration is not provided, even if it is repeatedly used over a long period of time, the electrophotographic photosensitive member is not charged poorly and image defects (image ghost) are suppressed. A process cartridge capable of stably obtaining an image is provided.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. FIG. 6 is a schematic configuration diagram illustrating another example of the image forming apparatus according to the present embodiment. 1 is a schematic partial cross-sectional view showing an example of an electrophotographic photosensitive member in the present embodiment. It is a general | schematic fragmentary sectional view which shows the other example of the electrophotographic photoreceptor in this embodiment. It is a general | schematic fragmentary sectional view which shows the other example of the electrophotographic photoreceptor in this embodiment.

The image forming apparatus according to the present embodiment includes an electrophotographic photosensitive member, a charging unit that charges the electrophotographic photosensitive member, an electrostatic latent image forming unit that forms an electrostatic latent image on the charged electrophotographic photosensitive member, A developing unit that develops an electrostatic latent image formed on the electrophotographic photosensitive member to form a toner image, a transfer unit that transfers the toner image to a transfer target, and the toner image that is transferred to the transfer target Potential unevenness removing means for removing potential unevenness on the surface of the subsequent electrophotographic photoreceptor, and toner removing means for removing residual toner on the surface of the electrophotographic photoreceptor after the toner image is transferred to the transfer target. The electrophotographic photoreceptor has a conductive substrate and a photosensitive layer provided on the surface of the conductive substrate, and the outermost surface layer of the photosensitive layer is at least one selected from a guanamine compound and a melamine compound. _If, -OH, -OCH 3, -NH , -SH, and a charge transporting material having at least one substituent selected from -COOH (hereinafter sometimes referred to as "specific charge transporting material".) Crosslinked using at least one, and A content of at least one of the outermost surface layers selected from the guanamine compound and the melamine compound is 0.1% by mass or more and 5% by mass or less, and the charge transporting material The content in the outermost surface layer is 95% by mass or more and 99% by mass or less.

  The image forming apparatus according to the present embodiment uses the electrophotographic photosensitive member having the above-described configuration, and removes the potential unevenness on the surface of the electrophotographic photosensitive member caused by the presence or absence of toner when transferring the toner image by the potential unevenness removing unit. As a result, it has been found and achieved that the effect of suppressing image defects (image ghosts) does not occur without causing poor charging of the electrophotographic photosensitive member.

  In the image forming apparatus according to this embodiment, at least the electrophotographic photosensitive member, the charging unit, the potential unevenness removing unit, and the toner removing unit may be a process cartridge that is detachably attached to the image forming apparatus.

In addition, the process cartridge according to the present embodiment is detached from the image forming apparatus main body, and at least after the electrophotographic photosensitive member, the charging unit for charging the electrophotographic photosensitive member, and the toner image are transferred to the transfer target. Potential unevenness removing means for removing the uneven charging on the surface of the electrophotographic photosensitive member, and toner removing means for removing the residual toner on the surface of the electrophotographic photosensitive member after the toner image is transferred to the transfer target, The electrophotographic photoreceptor includes a conductive substrate and a photosensitive layer provided on the surface of the conductive substrate, and the outermost surface layer of the photosensitive layer is at least one selected from a guanamine compound and a melamine compound; , —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH, and at least one charge transporting material having at least one substituent selected from —COOH, and , The content in the outermost surface layer of at least one selected from the guanamine compound and the melamine compound is 0.1% by mass or more and 5% by mass or less, and the content in the outermost surface layer of the charge transporting material The amount is 95% by mass or more and 99% by mass or less. In addition, in this embodiment, electroconductivity means a thing whose volume resistivity is 10 < ¹³ > ohm-cm or less. The volume resistivity in the present embodiment is a volume resistivity in a general environment (22 ° C., 50% RH).
Hereinafter, an image forming apparatus and a process cartridge according to the present embodiment will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present embodiment. An image forming apparatus 100 shown in FIG. 1 includes a process cartridge 300 including an electrophotographic photosensitive member 7, an exposure device (electrostatic latent image forming unit) 9, a transfer device (transfer unit) 40, and an intermediate transfer member 50. Prepare. In the image forming apparatus 100, the exposure device 9 is disposed at a position where the electrophotographic photosensitive member 7 is exposed from the opening of the process cartridge 300, and the transfer device 40 is disposed via the intermediate transfer member 50. The intermediate transfer member 50 is partly in contact with the electrophotographic photosensitive member 7.

  A process cartridge 300 in FIG. 1 includes, in a housing, an electrophotographic photosensitive member 7, a charging device (charging means) 8, a developing device (developing means) 11, a potential unevenness removing device (potential unevenness removing means) 15, and a cleaning device ( (Toner removing means) 13 is integrally supported. The cleaning device 13 has a cleaning blade (cleaning member) 131, and the cleaning blade 131 is disposed so as to contact the surface of the electrophotographic photosensitive member 7.

Further, an example is shown in which a fibrous member 132 (roll shape) for supplying the lubricant 14 to the surface of the photoreceptor 7 and a fibrous member 133 (flat brush shape) for assisting cleaning are used. It may be used accordingly.
Hereinafter, the image forming apparatus according to the present embodiment will be described for each component. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

The electrophotographic photoreceptor 7 has a conductive substrate and a photosensitive layer provided on the surface of the conductive substrate, and the outermost surface layer of the photosensitive layer is at least one selected from a guanamine compound and a melamine compound. , —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH, and at least one charge transporting material having at least one substituent selected from —COOH, and In the outermost surface layer of the charge transporting material, the content in the outermost surface layer of at least one selected from the guanamine compound and the melamine compound is 0.1% by mass or more and 5% by mass or less. Content is 95 mass% or more and 99 mass% or less, It is characterized by the above-mentioned.

  The electrophotographic photosensitive member 7 has the above-described configuration, so that wrinkles and unevenness are suppressed even when the outermost surface layer of the photosensitive layer is thickened, the mechanical strength of the outermost surface layer is high, and ghost resistance (ghosting) : An afterimage phenomenon caused by the history of the previous image remaining), deterioration of electrical characteristics and image quality characteristics due to repeated use over a long period of time is suppressed, and a stable image can be obtained. The reason for this is not clear, but is presumed as follows.

  A guanamine compound or melamine compound and a charge transporting material having a specific functional group can be polyfunctionalized at the cross-linking sites (cross-linking sites), highly cross-linked, increase mechanical strength, and change in electrical properties depending on the environment Is formed. And while reducing the amount of guanamine compound and melamine compound and increasing the amount of charge transporting material and increasing the amount compared to conventional electrophotographic photoreceptors, the electrical properties are maintained while maintaining this highly crosslinked state. With respect to the image quality, the rise in the residual potential is suppressed, the image quality characteristics are improved in ghost resistance, the deterioration of the electrical characteristics and the image quality characteristics is suppressed, and stable image quality is obtained. Further, by combining a guanamine compound or a melamine compound with a charge transporting material having a specific functional group, even if the amount of the charge transporting material is larger than that of a conventional electrophotographic photoreceptor, the outermost layer of the photosensitive layer Even if the film is thickened, wrinkles and unevenness are suppressed.

  Therefore, the electrophotographic photosensitive member according to this embodiment is presumed to have the above effect.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 3 is a schematic cross-sectional view showing a preferred embodiment of the electrophotographic photoreceptor according to the embodiment. 4 to 5 are schematic cross-sectional views showing electrophotographic photoreceptors according to other embodiments.

  The electrophotographic photoreceptor 7 shown in FIG. 3 is provided with a subbing layer 1 on a conductive substrate 4, and a photosensitive layer in which a charge generation layer 2, a charge transport layer 3, and a protective layer 5 are sequentially formed thereon. It has been.

  The electrophotographic photoreceptor 7 shown in FIG. 4 is provided with a photosensitive layer in which the functions are separated into the charge generation layer 2 and the charge transport layer 3, similarly to the electrophotographic photoreceptor 7 shown in FIG. 3. An electrophotographic photoreceptor 7 shown in FIG. 5 contains a charge generation material and a charge transport material in one layer (single-layer type photosensitive layer 6 (charge generation / charge transport layer)).

  In the electrophotographic photoreceptor 7 shown in FIG. 4, a photosensitive layer in which an undercoat layer 1 is provided on a conductive substrate 4 and a charge transport layer 3, a charge generation layer 2, and a protective layer 5 are sequentially formed thereon is provided. Is provided. Further, in the electrophotographic photoreceptor 7 shown in FIG. 5, the undercoat layer 1 is provided on the conductive substrate 4, and the photosensitive layer in which the single-layer type photosensitive layer 6 and the protective layer 5 are sequentially formed thereon is provided. It has been.

  The electrophotographic photoreceptor 7 shown in FIGS. 3 to 5 corresponds to the outermost surface layer. In the electrophotographic photoreceptor shown in FIGS. 3 to 5, the undercoat layer may or may not be provided.

  Hereinafter, each element will be described based on the electrophotographic photoreceptor 7 shown in FIG. 3 as a representative example.

<Conductive substrate>
Examples of the conductive substrate 4 include a metal plate, a metal drum, and a metal belt formed using a metal or an alloy such as aluminum, copper, zinc, stainless steel, chromium, nickel, molybdenum, vanadium, indium, gold, or platinum. Alternatively, a paper, a plastic film, a belt, or the like on which a conductive compound such as a conductive polymer or indium oxide, or a metal or alloy such as aluminum, palladium, or gold is applied, vapor-deposited, or laminated can be given. Here, as described above, “conductive” means that the volume resistivity is less than 10 ¹³ Ωcm.

  When the electrophotographic photoreceptor 7 is used in a laser printer, the surface of the conductive substrate 4 has a center line average roughness Ra of 0.04 μm or more and 0 in order to prevent interference fringes generated when laser light is irradiated. It is desirable to roughen the surface to 5 μm or less. If Ra is less than 0.04 μm, it becomes close to a mirror surface, so that the effect of preventing interference tends to be insufficient. If Ra exceeds 0.5 μm, the image quality tends to be rough even if a film is formed. When non-interfering light is used for the light source, it is not particularly necessary to roughen the interference fringes, and it is possible to prevent the occurrence of defects due to the irregularities on the surface of the conductive substrate 4, and thus it is suitable for longer life.

  Surface roughening methods include wet honing by suspending the abrasive in water and spraying it on the support, or centerless grinding and anodic oxidation in which the support is pressed against a rotating grindstone and continuously ground. Processing is desirable.

  As another roughening method, the surface of the conductive substrate 4 is not roughened, and the conductive or powder is dispersed in the resin to form a layer on the support surface. A method of roughening with particles dispersed therein is also desirably used.

  Here, the roughening treatment by anodic oxidation is to form an oxide film on the aluminum surface by anodizing in an electrolyte solution using aluminum as an anode. Examples of the electrolyte solution include a sulfuric acid solution and an oxalic acid solution. However, the porous anodic oxide film formed by anodic oxidation is chemically active as it is, easily contaminated, and has a large resistance fluctuation due to the environment. Therefore, the pores of the anodic oxide film are sealed with pressurized water vapor or boiling water (a metal salt such as nickel may be added) by volume expansion due to a hydration reaction, and a sealing process is performed to change to a more stable hydrated oxide. It is desirable.

  The thickness of the anodic oxide film is desirably 0.3 μm or more and 15 μm or less. When this film thickness is less than 0.3 μm, the barrier property against implantation tends to be poor and the effect tends to be insufficient. On the other hand, if it exceeds 15 μm, the residual potential tends to increase due to repeated use.

  Further, the conductive substrate 4 may be subjected to treatment with an acidic aqueous solution or boehmite treatment. The treatment with an acidic treatment liquid containing phosphoric acid, chromic acid and hydrofluoric acid is carried out as follows. First, an acidic treatment liquid is prepared. The mixing ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment liquid is such that phosphoric acid is in the range of 10% by mass to 11% by mass, chromic acid is in the range of 3% by mass to 5% by mass, and hydrofluoric acid is 0.00%. The concentration of these acids is preferably in the range of 13.5 mass% to 18 mass%. The treatment temperature is preferably 42 ° C. or more and 48 ° C. or less, but by keeping the treatment temperature high, a thicker film can be formed faster than when the treatment temperature is lower than the range. The film thickness is preferably from 0.3 μm to 15 μm. If it is less than 0.3 μm, the barrier property against injection tends to be poor and the effect tends to be insufficient. On the other hand, when it exceeds 15 μm, there is a tendency that the residual potential increases due to repeated use.

  The boehmite treatment is performed by immersing in pure water at 90 ° C. or more and 100 ° C. or less for 5 minutes or more and 60 minutes or less, or by contacting with heated steam at 90 ° C. or more and 120 ° C. or less for 5 minutes or more and 60 minutes or less. The film thickness is preferably 0.1 μm or more and 5 μm or less. This is further anodized using an electrolyte solution with lower film solubility than other types such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, citrate, etc. It may be processed.

<Underlayer>
The undercoat layer 1 is configured by containing inorganic particles in a binder resin, for example.
As the inorganic particles, powder resistance (volume resistivity) of 10 ² Ω · cm or more and 10 ¹¹ Ω · cm or less is desirably used. This is because the undercoat layer 1 needs to obtain an appropriate resistance for leak resistance and carrier block property acquisition. In addition, if the resistance value of the inorganic particles is lower than the lower limit of the above range, sufficient leakage resistance cannot be obtained, and if it is higher than the upper limit of this range, there is a concern that the residual potential is increased.

  Among these, inorganic particles (conductive metal oxide) such as tin oxide, titanium oxide, zinc oxide and zirconium oxide are preferably used as the inorganic particles having the above resistance value, and zinc oxide is particularly preferably used.

  Further, the inorganic particles may be subjected to a surface treatment, or may be used by mixing two or more kinds such as those having different surface treatments or particles having different particle diameters. The volume average particle size of the inorganic particles is desirably in the range of 50 nm to 2000 nm (desirably 60 to 1000).

As the inorganic particles, those having a specific surface area of 10 m ² / g or more by the BET method are desirably used. Those having a specific surface area value of less than 10 m ² / g tend to cause a decrease in chargeability and tend to make it difficult to obtain good electrophotographic characteristics.

  Further, by incorporating inorganic particles and an acceptor compound, a product having excellent electrical properties for a long period of time and carrier blockability can be obtained. Any acceptor compound may be used as long as the desired properties can be obtained, but quinone compounds such as chloranil and bromoanil, tetracyanoquinodimethane compounds, 2,4,7-trinitrofluorenone. Fluorenone compounds such as 2,4,5,7-tetranitro-9-fluorenone, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, Oxadiazole compounds such as 5-bis (4-naphthyl) -1,3,4-oxadiazole, 2,5-bis (4-diethylaminophenyl) 1,3,4-oxadiazole, xanthone compounds , Thiophene compounds, electron transporting materials such as diphenoquinone compounds such as 3,3 ′, 5,5 ′ tetra-t-butyldiphenoquinone, etc. are desirable In particular compounds having an anthraquinone structure are preferable. Furthermore, acceptor compounds having an anthraquinone structure such as hydroxyanthraquinone compounds, aminoanthraquinone compounds, aminohydroxyanthraquinone compounds, and the like are desirably used, and specific examples include anthraquinone, alizarin, quinizarin, anthralfin, and purpurin.

  The content of these acceptor compounds may be arbitrarily set as long as desired characteristics are obtained, but is desirably 0.01% by mass or more and 20% by mass or less with respect to the inorganic particles. Furthermore, 0.05 mass% or more and 10 mass% or less are desirable from a viewpoint of preventing charge accumulation and preventing aggregation of inorganic particles. Aggregation of the inorganic particles tends to cause variations in the formation of the conductive path, which not only tends to cause deterioration in sustainability such as an increase in residual potential when repeatedly used, but also tends to cause image quality defects such as black spots.

  The acceptor compound may be added only when the undercoat layer is applied, or may be previously attached to the surface of the inorganic particles. Examples of the method for imparting the acceptor compound to the surface of the inorganic particles include a dry method or a wet method.

  When surface treatment is performed by a dry method, dispersion is caused by dropping an acceptor compound dissolved in an organic solvent directly or with dry air or nitrogen gas while stirring inorganic particles with a mixer having a large shearing force. Processed without occurring. The addition or spraying is preferably performed at a temperature below the boiling point of the solvent. When spraying at a temperature equal to or higher than the boiling point of the solvent, the solvent evaporates before stirring without causing variation, and the acceptor compound is locally concentrated, which makes it difficult to perform processing without variation. After addition or spraying, baking may be performed at 100 ° C. or higher. Baking is carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained.

  As a wet method, the inorganic particles are dispersed in a solvent using stirring, ultrasonic waves, a sand mill, an attritor, a ball mill, etc., added with an acceptor compound, stirred or dispersed, and then the solvent is removed without causing variations. It is processed. The solvent removal method is distilled off by filtration or distillation. After removing the solvent, baking may be performed at 100 ° C. or higher. Baking is carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained. In the wet method, water containing inorganic particles can also be removed before adding the surface treatment agent. For example, a method of removing with stirring and heating in a solvent used for the surface treatment, a method of removing by azeotropic distillation with the solvent May be used.

  In addition, the inorganic particles may be subjected to a surface treatment before the acceptor compound is provided. The surface treatment agent is not particularly limited as long as it has desired characteristics and is selected from known materials. For example, a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, a surfactant, and the like can be given. In particular, silane coupling agents are desirably used because they provide good electrophotographic properties. Further, a silane coupling agent having an amino group is desirably used because it gives the undercoat layer 1 good blocking properties.

  Any silane coupling agent having an amino group may be used as long as the desired electrophotographic photoreceptor characteristics can be obtained. Specific examples include γ-aminopropyltriethoxysilane, N-β-. (Aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, etc. However, it is not limited to these.

  Two or more silane coupling agents may be mixed and used. Examples of the silane coupling agent that may be used in combination with the silane coupling agent having an amino group include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl)- γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltri Examples include methoxysilane, etc. Not intended to be constant.

  As the surface treatment method, any known method may be used, but a dry method or a wet method is preferably used. Moreover, you may perform surface treatment by acceptor provision and a coupling agent etc. simultaneously.

  The amount of the silane coupling agent relative to the inorganic particles in the undercoat layer 1 is arbitrarily set as long as the desired electrophotographic characteristics can be obtained, but from the viewpoint of improving dispersibility, 0.5 mass with respect to the inorganic particles. % To 10% by mass is desirable.

  As the binder resin contained in the undercoat layer 1, any known resin may be used as long as it can form a good film and can obtain desired characteristics. For example, polyvinyl butyral Acetal resin, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin , Silicone resins, silicone-alkyd resins, phenolic resins, phenol-formaldehyde resins, melamine resins, urethane resins and other known polymer resin compounds, charge transporting resins having a charge transporting group, and conductive resins such as polyaniline, etc. Is used. Among these, resins that are insoluble in the upper coating solvent are preferably used, and phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, epoxy resins, and the like are particularly preferable. When these are used in combination of two or more, the mixing ratio is set as necessary.

  The ratio of the metal oxide to which the acceptor property is imparted in the coating solution for forming the undercoat layer and the binder resin, or the inorganic particles and the binder resin is arbitrarily set within a range in which desired electrophotographic photoreceptor characteristics can be obtained.

  Various additives may be used in the undercoat layer 1 in order to improve electrical characteristics, environmental stability, and image quality. As additives, known materials such as polycyclic condensation type, azo type electron transporting pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, silane coupling agents, and the like are used. It is done. The silane coupling agent is used for the surface treatment of the metal oxide, but may be further added to the coating solution as an additive. Specific examples of the silane coupling agent used here include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ- Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (Aminoethyl) -γ-aminopropylmethyldimethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane and the like. Examples of zirconium chelate compounds include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl zirconium acetoacetate, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, naphthene. Zirconate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

Examples of titanium chelate compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, Examples thereof include titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.

Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.

  These compounds may be used alone or as a mixture or polycondensate of a plurality of compounds.

  As a solvent for adjusting the coating solution for forming the undercoat layer, any known organic solvent such as alcohol, aromatic, halogenated hydrocarbon, ketone, ketone alcohol, ether, ester, etc. Selected. Examples of the solvent include methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, Usual organic solvents such as dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene and toluene are used.

  Moreover, you may use the solvent used for these dispersion | distribution individually or in mixture of 2 or more types. When mixing, any solvent can be used as long as it can dissolve the binder resin as the mixed solvent.

  As a dispersion method, known methods such as a roll mill, a ball mill, a vibration ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker can be used. Further, as the coating method used when the undercoat layer 1 is provided, conventional methods such as blade coating method, wire bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain coating method, etc. Is used.

  The undercoat layer 1 is formed on the conductive substrate using the undercoat layer-forming coating solution thus obtained.

The undercoat layer 1 preferably has a Vickers hardness of 35 or more.
Furthermore, the undercoat layer 1 is set to any thickness as long as desired characteristics can be obtained. The thickness is preferably 15 μm or more, and more preferably 15 μm or more and 50 μm or less.

  When the thickness of the undercoat layer 1 is less than 15 μm, sufficient leakage resistance cannot be obtained, and when it is 50 μm or more, residual potential tends to remain when used for a long period of time, so that it tends to cause an abnormal image density. There are drawbacks.

  Further, the surface roughness (ten-point average roughness) of the undercoat layer 1 is from 1 / 4n (n is the refractive index of the upper layer) to 1 / 2λ of the exposure laser wavelength λ used to prevent moire images. Adjusted to In order to adjust the surface roughness, particles such as a resin may be added to the undercoat layer. As the resin particles, silicone resin particles, cross-linked polymethyl methacrylate resin particles, and the like are used.

  Here, the undercoat layer contains a binder resin and a conductive metal oxide, and has a light transmittance of 40% or less (preferably 10% or more and 35% or less, more preferably 15%) with respect to light having a wavelength of 950 nm at a thickness of 20 μm. % Or more and 30% or less). It is necessary to maintain stable high image quality in an electrophotographic photosensitive member aimed at extending the life. Similar characteristics are also required when a crosslinkable outermost surface layer (protective layer) is used. When a crosslinkable outermost layer (protective layer) is used, an acid catalyst is often used for curing, and the greater the amount relative to the solid content in the outermost surface layer (protective layer), the higher the film strength. Since the printing durability can be improved, the service life is extended. On the other hand, the residual catalyst in the bulk becomes a charge trap site, so that the light fatigue resistance is lowered, and this causes image density unevenness due to light exposure during maintenance.

  This light resistance (light fatigue resistance) is improved to a level where there is no problem in practical use by optimizing the amount of the material (especially charge transport material, acid catalyst), but a bright environment such as a normal office, for example, It is not sufficient for high-intensity and long-time exposure, such as when irradiating at a showroom or when observing foreign matter adhering to the surface of an electrophotographic photoreceptor. It is necessary to increase the curing catalyst and increase the film strength, but in that case, the light resistance may not be sufficient. Therefore, by using an undercoat layer having the above-described light transmittance (that is, low light transmittance), the undercoat layer absorbs light incident on the electrophotographic photosensitive member, so that light resistance to strong light is obtained. The image can be obtained stably over a long period of time. That is, since the reflected light from the surface of the conductive substrate is reduced, light resistance (light fatigue resistance) is obtained against light exposure for a long time with high brightness, and the amount of curing catalyst is increased, for example, the outermost surface layer (protective layer) ) Longer life can be achieved even if strength is increased and printing durability is improved.

  The light transmittance of the undercoat layer is measured as follows. The undercoat layer forming coating solution is applied on a glass plate so that the thickness after drying is 20 μm. After drying, the light transmittance of the film at a wavelength of 950 nm is measured using a spectrophotometer. For the light transmittance by the photometer, an apparatus name “Spectrophotometer (U-2000)” manufactured by Hitachi, Ltd. is used as a spectrophotometer.

  The light transmittance of the undercoat layer is controlled by adjusting the dispersion time during dispersion using the roll mill, ball mill, vibration ball mill, attritor, sand mill, colloid mill, paint shaker, or the like. The dispersion time is not particularly limited, but is preferably any time from 5 minutes to 1000 hours, and more preferably from 30 minutes to 10 hours. When the dispersion time is increased, the light transmittance tends to decrease.

  Further, the undercoat layer may be polished for adjusting the surface roughness. As a polishing method, buffing, sandblasting, wet honing, grinding, or the like can be used.

  The coated layer is dried to obtain an undercoat layer. Usually, the drying is performed at a temperature at which the solvent is evaporated and a film is formed.

<Charge generation layer>
The charge generation layer 2 is a layer containing a charge generation material and a binder resin.
Examples of the charge generation material include azo pigments such as bisazo and trisazo, condensed aromatic pigments such as dibromoanthanthrone, perylene pigments, pyrrolopyrrole pigments, phthalocyanine pigments, zinc oxide, and trigonal selenium. Among these, metal and metal-free phthalocyanine pigments are desirable for near-infrared laser exposure. In particular, hydroxygallium phthalocyanine disclosed in JP-A-5-263007, JP-A-5-279591, and the like. Chlorogallium phthalocyanine disclosed in JP-A-5-98181, dichlorotin phthalocyanine disclosed in JP-A-5-140472, JP-A-5-140473, etc., JP-A-4-189873, More preferred is titanyl phthalocyanine disclosed in Kaihei 5-43823. For near-ultraviolet laser exposure, condensed aromatic pigments such as dibromoanthanthrone, thioindigo pigments, porphyrazine compounds, zinc oxide, and trigonal selenium are more desirable. As the charge generation material, an inorganic pigment is desirable when a light source with an exposure wavelength of 380 nm to 500 nm is used, and a metal and a metal-free phthalocyanine pigment are desirable when a light source with an exposure wavelength of 700 nm or less and 800 nm is used.

  As the charge generation material, it is desirable to use a hydroxygallium phthalocyanine pigment having a maximum peak wavelength in a range of 810 nm to 839 nm in a spectral absorption spectrum in a wavelength range of 600 nm to 900 nm. This hydroxygallium phthalocyanine pigment is different from the conventional V-type hydroxygallium phthalocyanine pigment, and is desirable because it provides better dispersibility. Thus, by shifting the maximum peak wavelength of the spectral absorption spectrum to a shorter wavelength side than the conventional V-type hydroxygallium phthalocyanine pigment, it becomes a fine hydroxygallium phthalocyanine pigment in which the crystal arrangement of the pigment particles is suitably controlled, When used as a material for an electrophotographic photosensitive member, excellent dispersibility and sufficient sensitivity, chargeability, and dark decay characteristics can be obtained.

The hydroxygallium phthalocyanine pigment having the maximum peak wavelength in the range of 810 nm to 839 nm is preferably in a specific range for the average particle size and in a specific range for the BET specific surface area. Specifically, the average particle size is desirably 0.20 μm or less, more desirably 0.01 μm or more and 0.15 μm or less, while the BET specific surface area is desirably 45 m ² / g or more. 50 m ² / g or more is more desirable, and 55 m ² / g or more and 120 m ² / g or less is particularly desirable. The average particle size is a volume average particle size (d50 average particle size) measured by a laser diffraction / scattering particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.). Moreover, it is the value measured by the nitrogen substitution method using the BET-type specific surface area measuring device (Shimadzu Corporation make: Flow soap II2300).

When the average particle diameter is larger than 0.20 μm, or when the specific surface area value is less than 45 m ² / g, the pigment particles are coarsened or aggregates of the pigment particles are formed, and the electrophotographic photosensitive member When used as a material, there is a tendency that defects are likely to occur in characteristics such as dispersibility, sensitivity, chargeability, and dark decay characteristics, thereby tending to cause image quality defects.

  The maximum particle diameter (maximum primary particle diameter) of the hydroxygallium phthalocyanine pigment is desirably 1.2 μm or less, more desirably 1.0 μm or less, and more desirably 0.3 μm or less. is there. When the maximum particle size exceeds the above range, minute black spots tend to occur.

Furthermore, from the viewpoint of more reliably suppressing density unevenness caused by exposure of the photoreceptor to a fluorescent lamp or the like, the hydroxygallium phthalocyanine pigment has an average particle size of 0.2 μm or less and a maximum particle size of 1.2 μm. The specific surface area value is preferably 45 m ² / g or more.

  In addition, the hydroxygallium phthalocyanine pigment described above has Bragg angles (2θ ± 0.2 °) of 7.5 °, 9.9 °, 12.5 °, and 16.5 in an X-ray diffraction spectrum using CuKα characteristic X-rays. It is desirable to have diffraction peaks at 3 °, 18.6 °, 25.1 ° and 28.3 °.

The hydroxygallium phthalocyanine pigment preferably has a thermal weight reduction rate of 2.0% or more and 4.0% or less when heated from 25 ° C. to 400 ° C., and preferably 2.5% or more and 3.8%. % Or less is more desirable. The thermal weight reduction rate is measured by a thermobalance or the like. When the thermal weight reduction rate exceeds 4.0%, the impurities contained in the hydroxygallium phthalocyanine pigment affect the electrophotographic photosensitive member, and the sensitivity characteristics, potential stability during repeated use, and image quality decrease. Tend to occur. Further, if it is less than 2.0%, the sensitivity tends to be lowered. This is considered to be due to the fact that the hydroxygallium phthalocyanine pigment exhibits a sensitizing action by interaction with the solvent molecules contained in the crystal.
When the above-described hydroxygallium phthalocyanine pigment is used as a charge generation material for an electrophotographic photoreceptor, the optimum sensitivity and excellent photoelectric characteristics of the photoreceptor can be obtained, and the binder resin contained in the photosensitive layer can be obtained. Since it has excellent dispersibility, it is particularly effective in that it has excellent image quality characteristics.

  Here, it has been known that by defining the average particle diameter and BET specific surface area of the hydroxygallium phthalocyanine pigment, it is possible to suppress the occurrence of initial fogging and sunspots. was there. On the other hand, by combining the outermost surface layer described later (a protective layer made of a crosslinked film using at least one selected from a guanamine compound and a melamine compound and a specific charge transport material), Generation of fog and black spots due to long-term use, which has been a problem with the combination of charge generation layers, can be suppressed. This is presumably because film wear and chargeability degradation caused by long-term use are suppressed by using the protective layer. In addition, it is possible to suppress fogging and black spots that have been generated in the conventional photoconductors even for thinning of the charge transport layer, which is effective in improving electrical characteristics (reducing residual potential).

The binder resin used for the charge generation layer 2 is selected from a wide range of insulating resins, and selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. Also good. Desirable binder resins include polyvinyl butyral resins, polyarylate resins (polycondensates of bisphenols and aromatic divalent carboxylic acids, etc.), polycarbonate resins, polyester resins, phenoxy resins, vinyl chloride-vinyl acetate copolymers, polyamides. Resins, acrylic resins, polyacrylamide resins, polyvinyl pyridine resins, cellulose resins, urethane resins, epoxy resins, caseins, polyvinyl alcohol resins, polyvinyl pyrrolidone resins, and the like. These binder resins are used singly or in combination of two or more. The blending ratio of the charge generation material and the binder resin is preferably in the range of 10: 1 to 1:10 by mass ratio. Here, “insulating” means here that “insulating” means that the volume resistivity is 10 ¹³ Ωcm or more.

  The charge generation layer 2 is formed using a coating liquid in which the charge generation material and the binder resin are dispersed in a solvent.

  Solvents used for dispersion include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, and methylene chloride. , Chloroform, chlorobenzene, toluene and the like. These may be used alone or in admixture of two or more.

  In addition, as a method for dispersing the charge generating material and the binder resin in the solvent, usual methods such as a ball mill dispersion method, an attritor dispersion method, and a sand mill dispersion method can be used. By these dispersion methods, changes in the crystal form of the charge generation material due to dispersion are prevented. Further, at the time of dispersion, it is effective that the average particle size of the charge generating material is 0.5 μm or less, desirably 0.3 μm or less, and more desirably 0.15 μm or less.

  Further, when forming the charge generation layer 2, a usual method such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method is used. .

  The film thickness of the charge generation layer 2 obtained in this way is desirably 0.1 μm or more and 5.0 μm or less, and more desirably 0.2 μm or more and 2.0 μm or less.

<Charge transport layer>
The charge transport layer 3 is formed containing a charge transport material and a binder resin, or containing a polymer charge transport material.
Examples of charge transport materials include quinone compounds such as p-benzoquinone, chloranil, bromanyl, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, xanthone compounds, benzophenone compounds , Electron transport compounds such as cyanovinyl compounds and ethylene compounds, triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds, etc. Examples thereof include pore-transporting compounds. These charge transport materials may be used alone or in combination of two or more, but are not limited thereto.

  As the charge transport material, from the viewpoint of charge mobility, a triarylamine derivative represented by the following structural formula (a-1) and a benzidine derivative represented by the following structural formula (a-2) are desirable.

(In Structural Formula (a-1), R ⁸ represents a hydrogen atom or a methyl group. N represents 1 or 2. Ar ⁶ and Ar ⁷ are each independently a substituted or unsubstituted aryl group, —C _{6. ^{H 4 -C (R 9) =}} C (R 10) (R 11), or _{-C 6 H 4 -CH = CH-} CH = C (R 12) shows the ^{(R 13), R 9} to ^{R 13} are Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, including a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms; A substituted amino group substituted with a group or an alkyl group having 1 to 3 carbon atoms.)

(In Structural Formula (a-2), R ¹⁴ and R ^{14 ′} may be the same or different, and each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or 1 to 5 carbon atoms. ^.R 15, ^{R 15} to an alkoxy group, ^{', R 16,} and ^{R 16'} may be the same or different, each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, 1 to 4 carbon atoms Or more, an alkoxy group having 5 or less, an amino group substituted with an alkyl group having 1 to 2 carbon atoms, a substituted or unsubstituted aryl group, -C (R ¹⁷ ) = C (R ¹⁸ ) (R ¹⁹ ), or- CH = CH—CH═C (R ²⁰ ) (R ²¹ ), wherein R ^{17 to} R ²¹ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. And n are each independently 0 or more and 2 It represents an integer of below.)

Here, among the triarylamine derivatives represented by the structural formula (a-1) and the benzidine derivatives represented by the structural formula (a-2), in particular, “—C ₆ H ₄ —CH═CH—CH ═C (R ¹² ) (R ¹³ ) ”and a benzidine derivative having“ —CH═CH—CH═C (R ²⁰ ) (R ²¹ ) ”have charge mobility, protective layer and It is excellent and desirable from the standpoints of adhesiveness and afterimage (hereinafter sometimes referred to as “ghost”) caused by the history of the previous image remaining.

  The binder resin used for the charge transport layer 3 is polycarbonate resin, polyester resin, polyarylate resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer. , Vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly- N-vinyl carbazole, polysilane, etc. are mentioned. Further, as described above, polymer charge transport materials such as polyester-based polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 may be used. These binder resins are used singly or in combination of two or more. The blending ratio of the charge transport material and the binder resin is desirably 10: 1 to 1: 5 by mass ratio.

  In particular, as the binder resin, at least one of a polycarbonate resin having a viscosity average molecular weight of 50,000 to 80,000 and a polyacrylate resin having a viscosity average molecular weight of 50,000 to 80,000 is desirable. As described above, the electrophotographic photosensitive member has light resistance. It may not be enough. Therefore, by using a charge transport layer containing a resin having the above molecular weight, the charge transport layer absorbs light incident on the electrophotographic photosensitive member, so that it has excellent light resistance against strong light and is stable for a long time. To obtain an image. That is, since the reflected light from the surface of the conductive substrate is reduced, light resistance (light fatigue resistance) is obtained against light exposure for a long time with high brightness, and the amount of curing catalyst is increased, for example, the outermost surface layer (protective layer) ) Longer life can be achieved even if strength is increased and printing durability is improved.

  In addition, a polymer charge transport material may be used as the charge transport material. As the polymer charge transporting material, known materials having charge transporting properties such as poly-N-vinylcarbazole and polysilane are used. In particular, polyester polymer charge transport materials disclosed in JP-A-8-176293, JP-A-8-208820 and the like have a higher charge transportability than other types, and are particularly desirable. is there. The polymer charge transporting material is formed by itself, but may be formed by mixing with a binder resin described later.

  The charge transport layer 3 is formed using a charge transport layer forming coating solution containing the above-described constituent materials. Solvents used in the coating solution for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, and halogenation such as methylene chloride, chloroform and ethylene chloride. Ordinary organic solvents such as aliphatic hydrocarbons, cyclic ethers such as tetrahydrofuran and ethyl ether or linear ethers may be used alone or in combination of two or more. Moreover, a well-known method is used as a dispersion method of each said constituent material.

  The coating method for applying the charge transport layer forming coating solution onto the charge generation layer 2 includes blade coating method, Mayer bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, A usual method such as a curtain coating method is used.

  The film thickness of the charge transport layer 3 is desirably 5 μm or more and 50 μm or less, and more desirably 10 μm or more and 30 μm or less.

<Protective layer>
The protective layer 5 is the outermost surface layer in the electrophotographic photosensitive member 7 and is a layer provided in order to give resistance to abrasion and scratches on the outermost surface and to increase toner transfer efficiency.

The protective layer 5 has a charge transport having at least one selected from a guanamine compound and a melamine compound and at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. It is comprised including the crosslinked material using the coating liquid containing at least 1 sort (s) of an active material.

First, the guanamine compound will be described.
The guanamine compound is a compound having a guanamine skeleton (structure), and examples thereof include acetoguanamine, benzoguanamine, formoguanamine, steroguanamine, spiroguanamine, and cyclohexylguanamine.

  The guanamine compound is particularly preferably at least one of a compound represented by the following general formula (A) and a multimer thereof. Here, the multimer is an oligomer polymerized using the compound represented by the general formula (A) as a structural unit, and the degree of polymerization thereof is, for example, 2 or more and 200 or less (preferably 2 or more and 100 or less). The compound represented by the general formula (A) may be used alone or in combination of two or more. In particular, when the compound represented by the general formula (A) is used as a mixture of two or more kinds, or used as a multimer (oligomer) having the structural unit as a structural unit, the solubility in a solvent is improved.

In general formula (A), R ₁ is a linear or branched alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, or 4 to 10 carbon atoms. The following substituted or unsubstituted alicyclic hydrocarbon groups are shown. R _{2 to} R ₅ each independently represent hydrogen, —CH ₂ —OH, or —CH ₂ —O—R ₆ . R ₆ represents hydrogen or a linear or branched alkyl group having 1 to 10 carbon atoms.

In the general formula (A), the alkyl group representing R ₁ has 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, more preferably 1 to 5 carbon atoms. . The alkyl group may be linear or branched.

In general formula (A), the phenyl group represented by R ₁ has 6 to 10 carbon atoms, and more preferably 6 to 8 carbon atoms. Examples of the substituent substituted with the phenyl group include a methyl group, an ethyl group, and a propyl group.

In general formula (A), the alicyclic hydrocarbon group representing R ₁ has 4 to 10 carbon atoms, and more preferably 5 to 8 carbon atoms. Examples of the substituent substituted with the alicyclic hydrocarbon group include a methyl group, an ethyl group, and a propyl group.

In the general formula (A), in “—CH ₂ —O—R ₆ ” representing R _{2 to} R ₅ , the alkyl group representing R ₆ has 1 to 10 carbon atoms, and desirably has carbon atoms. 1 or less and 8 or more, and more preferably 1 or more and 6 or less. The alkyl group may be linear or branched. Desirably, a methyl group, an ethyl group, a butyl group, etc. are mentioned.

As the compound represented by the general formula (A), it is particularly desirable that R ₁ represents a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, and R _{2 to} R ₅ are each independently —CH ₂ —O. It is a compound represented by —R ₆ . R ₆ is preferably selected from a methyl group and an n-butyl group.

  The compound represented by the general formula (A) is synthesized by, for example, a known method using guanamine and formaldehyde (for example, Experimental Chemistry Course 4th Edition, Volume 28, page 430).

  Hereinafter, as specific examples of the compound represented by the general formula (A), exemplary compounds: (A) -1 to exemplary compounds: (A) -42 are shown, but are not limited thereto. Moreover, although the following specific examples show the thing of a monomer, the multimer (oligomer) which uses these as a structural unit may be sufficient. In this embodiment, “Me” represents a methyl group, “Bu” represents a butyl group, and “Ph” represents a phenyl group.

  Commercially available products of the compound represented by the general formula (A) include, for example, “Superbecamine (R) L-148-55, Superbecamine (R) 13-535, Superbecamine (R) L-145- 60, Superbecamine (R) TD-126 "manufactured by Dainippon Ink Co., Ltd.," Nicarac BL-60, Nicarac BX-4000 "manufactured by Nippon Carbide, and the like.

  In addition, the compound represented by the general formula (A) (including multimers) can be used in a suitable solvent such as toluene, xylene, ethyl acetate, etc., in order to remove the influence of residual catalyst after synthesis or after purchasing a commercial product. It may be dissolved and washed with distilled water, ion exchange water or the like, or may be removed by treatment with an ion exchange resin.

Next, the melamine compound will be described.
The melamine compound is a melamine skeleton (structure), and is particularly preferably at least one of a compound represented by the following general formula (B) and a multimer thereof. Here, the multimer is an oligomer polymerized using the compound represented by the general formula (B) as a structural unit in the same manner as the general formula (A), and the degree of polymerization thereof is, for example, 2 or more and 200 or less (preferably 2 or more). 100 or less). In addition, the compound shown by the general formula (B) or the multimer thereof may be used alone or in combination of two or more. Moreover, you may use together with the compound shown by the said general formula (A), or its multimer. In particular, when the compound represented by the general formula (B) is used as a mixture of two or more kinds or used as a multimer (oligomer) having the structural unit as a structural unit, the solubility in a solvent is improved.

In general formula (B), R ^{6 to} R ¹¹ each independently represent a hydrogen atom, —CH ₂ —OH, —CH ₂ —O—R ¹² , and R ¹² is branched from 1 to 5 carbon atoms. Or a good alkyl group. Examples of the alkyl group include a methyl group, an ethyl group, and a butyl group.

  The compound represented by the general formula (B) is synthesized by, for example, a known method using melamine and formaldehyde (for example, synthesized in the same manner as the melamine resin in Experimental Chemistry Course 4th edition, Volume 28, page 430). Is done.

  Hereinafter, as specific examples of the compound represented by the general formula (B), exemplary compounds: (B) -1 to exemplary compounds: (B) -7 are shown, but are not limited thereto. However, the present invention is not limited to these. Moreover, although the following specific examples show the thing of a monomer, the multimer (oligomer) which uses these as a structural unit may be sufficient.

  As a commercial item of the compound represented by the general formula (B), for example, Super Melami No. 90 (Nippon Yushi Co., Ltd.), Super Becamine (R) TD-139-60 (Dainippon Ink Co., Ltd.), Uban 2020 (Mitsui Chemicals), Smitex Resin M-3 (Sumitomo Chemical), Nicarak MW-30 (Made by Nippon Carbide).

  In addition, the compound represented by the general formula (B) (including multimers) can be used in an appropriate solvent such as toluene, xylene, ethyl acetate, etc., in order to remove the influence of residual catalyst after synthesis or after purchasing a commercial product. It may be dissolved and washed with distilled water, ion exchange water or the like, or may be removed by treatment with an ion exchange resin.

Next, a specific charge transport material will be described. As the specific charge transporting material, for example, a material having at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH is preferably exemplified. In particular, the specific charge transporting material preferably has at least two (or three) substituents selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. It is done. As described above, the increase in reactive functional groups (substituents) in a specific charge transporting material increases the crosslink density, resulting in a cross-linked film with higher strength, particularly when using a blade cleaner. The rotational torque of the body is reduced, and the damage to the blade is suppressed and the wear of the electrophotographic photosensitive member is suppressed. Although details of this are unknown, since a cured film having a high crosslinking density can be obtained by increasing the number of reactive functional groups, the molecular motion on the extreme surface of the electrophotographic photoreceptor is suppressed, and the surface molecules of the blade member It is presumed that this interaction weakens.

The specific charge transporting material is preferably a compound represented by the following general formula (I).
_{F - ((- R 1 -X} ) n1 R 2 -Y) n2 (I)

In general formula (I), F is an organic group derived from a compound having a hole transporting ability, R ₁ and R ₂ are each independently a linear or branched alkylene group having 1 to 5 carbon atoms. N1 represents 0 or 1, and n2 represents an integer of 1 or more and 4 or less. X represents an oxygen, NH, or sulfur atom, and Y represents —OH, —OCH ₃ , —NH ₂ , —SH, or —COOH.

  In general formula (I), an arylamine derivative is preferably used as the compound having a hole transporting ability in an organic group derived from a compound having a hole transporting ability represented by F. Preferred examples of the arylamine derivative include a triphenylamine derivative and a tetraphenylbenzidine derivative.

  The compound represented by the general formula (I) is preferably a compound represented by the following general formula (II). The compound represented by the general formula (II) is particularly excellent in charge mobility, stability against oxidation and the like.

In general formula (II), Ar ^{1 to} Ar ⁴ may be the same or different and each independently represents a substituted or unsubstituted aryl group, and Ar ⁵ represents a substituted or unsubstituted aryl group or a substituted or unsubstituted group. D represents — (— R ₁ —X) _n1 R ₂ —Y, c represents 0 or 1 independently, k represents 0 or 1, and the total number of D is 1 or more and 4 It is as follows. R ₁ and R ₂ each independently represent a linear or branched alkylene group having 1 to 5 carbon atoms, n1 represents 0 or 1, X represents an oxygen, NH, or sulfur atom. , Y represents —OH, —OCH ₃ , —NH ₂ , —SH, or —COOH.

In the general formula (II), “— (— R ₁ —X) _n1 R ₂ —Y” representing D is the same as in the general formula (I), and R ₁ and R ₂ each independently have 1 or more carbon atoms. 5 or less linear or branched alkylene group. N1 is preferably 1. X is preferably oxygen. Y is preferably a hydroxyl group.
The total number of D in the general formula (II) corresponds to n2 in the general formula (I), preferably 2 or more and 4 or less, and more preferably 3 or more and 4 or less. That is, in the general formula (I) and the general formula (II), when the molecular weight is desirably 2 or more and 4 or less, more desirably 3 or more and 4 or less in one molecule, the crosslinking density increases and a crosslinked film with higher strength can be obtained. In particular, the rotational torque of the electrophotographic photosensitive member when using a blade cleaner is reduced, so that damage to the blade and wear of the electrophotographic photosensitive member are suppressed. Although the details are unknown, increasing the number of reactive functional groups results in a cured film having a high crosslink density, which suppresses molecular motion on the extreme surface of the electrophotographic photosensitive member and interacts with the blade member surface molecules. It is presumed that the action is weakened.

In general formula (II), Ar _{1 to} Ar ₄ are preferably any of the following formulas (1) to (7). Incidentally, the following equation (1) to (7) can be coupled to each Ar ₁ to Ar ₄ - shown with _{"(D) C".}

In the formulas (1) to (7), R ⁹ is phenyl substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Represents a group selected from the group consisting of a group, an unsubstituted phenyl group, and an aralkyl group having 7 to 10 carbon atoms, wherein R ^{10 to} R ¹² are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and a carbon number, respectively. One selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms, a phenyl group substituted with an alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom Ar represents a substituted or unsubstituted arylene group, D and c are the same as “D” and “c” in formula (II), s represents 0 or 1, and t represents 1 or more, respectively. Integer less than 3 Represent. ]

  Here, as Ar in Formula (7), what is represented by following formula (8) or (9) is desirable.

[In the formulas (8) and (9), R ¹³ and R ¹⁴ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. 1 represents one selected from the group consisting of a phenyl group substituted with, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, and t represents an integer of 1 to 3. ]

  Further, Z ′ in the formula (7) is preferably represented by any one of the following formulas (10) to (17).

[In the formulas (10) to (17), R ¹⁵ and R ¹⁶ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Represents a phenyl group substituted with, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, W represents a divalent group, q and r each represent Represents an integer of 1 to 10, and t represents an integer of 1 to 3. ]

  W in the formulas (16) to (17) is preferably any one of divalent groups represented by the following (18) to (26). However, in formula (25), u represents an integer of 0 or more and 3 or less.

In general formula (II), Ar ⁵ is the aryl group of the above (1) to (7) exemplified in the description of Ar ^{1 to} Ar ⁴ when k is 0, and when k is 1, An arylene group obtained by removing a hydrogen atom from the aryl groups of the above (1) to (7).

  Specific examples of the compound represented by the general formula (I) include the following exemplified compounds: I-1 to exemplified compounds: I-34. In addition, the compound shown by the said general formula (I) is not limited at all by these.

  Here, the solid content concentration in at least one coating liquid selected from a guanamine compound (a compound represented by the general formula (A)) and a melamine compound (a compound represented by the general formula (B)) is 0.1 mass. % Or more and 5% by mass or less, preferably 1% by mass or more and 3% by mass or less. Compared with the case where the solid content concentration is within the above range, if it is less than the above range, it is difficult to obtain a dense film, so that it is difficult to obtain sufficient strength, and if it exceeds the above range, the electrical characteristics and ghost resistance deteriorate. .

  On the other hand, the solid content concentration of the specific charge transporting material in at least one kind of the coating liquid is 95% by mass or more and 99% by mass or less, and desirably 97% by mass or more and 99% by mass or less. When the solid content concentration is less than the above range, the electrical characteristics are deteriorated as compared with the case where the solid content concentration is within the above range. In addition, although it is desirable that the solid content concentration is large, at least one selected from a guanamine compound (a compound represented by the general formula (A)) and a melamine compound (a compound represented by the general formula (B)), and others In view of the effective function of the additive, it is 99% by mass or less.

Hereinafter, the protective layer 5 will be described in more detail.
The protective layer 5 includes at least one selected from a guanamine compound (a compound represented by the general formula (A)) and a melamine compound (a compound represented by the general formula (B)) and a specific charge transporting material (general formula). A phenol resin, a melamine resin, a urea resin, an alkyd resin, or the like may be mixed and used together with a crosslinked product with the compound represented by (I). Further, in order to improve the strength, a compound having more functional groups in one molecule such as spiroacetal guanamine resin (for example, “CTU-guanamine” (Ajinomoto Fine Techno Co., Ltd.)) is used as the material in the crosslinked product. Copolymerization is also effective.

  In addition, other heat such as phenol resin, melamine resin, and benzoguanamine resin is added to the protective layer 5 for the purpose of effectively suppressing oxidation by the discharge generated gas by adding so as not to absorb the discharge generated gas excessively. A curable resin may be mixed and used.

  In addition, it is desirable to add a surfactant to the protective layer 5, and the surfactant to be used is particularly a surfactant that includes at least one type of structure among a fluorine atom, an alkylene oxide structure, and a silicone structure. Although there is no limitation, those having a plurality of the above structures have high affinity and compatibility with the charge transporting organic compound, and the film forming property of the coating liquid for the protective layer is improved, and wrinkles and unevenness of the protective layer 5 are suppressed. Therefore, it is preferable.

  There are various surfactants having a fluorine atom. Specific examples of the surfactant having a fluorine atom and an acrylic structure include Polyflow KL600 (manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF-351, EF-352, EF-801, EF-802, EF-601 (above, JEMCO Manufactured). The surfactant having an acrylic structure mainly includes those obtained by polymerizing or copolymerizing monomers such as acrylic or methacrylic compounds.

Specific examples of the surfactant having a perfluoroalkyl group as a fluorine atom include perfluoroalkyl sulfonic acids (for example, perfluorobutane sulfonic acid, perfluorooctane sulfonic acid), and perfluoroalkyl carboxylic acids (for example, , Perfluorobutanecarboxylic acid, perfluorooctanecarboxylic acid, etc.) and perfluoroalkyl group-containing phosphates. Perfluoroalkylsulfonic acids and perfluoroalkylcarboxylic acids may be salts thereof and amide-modified products thereof.
Examples of commercially available perfluoroalkyl sulfonic acids include MegaFuck F-114 (manufactured by Dainippon Ink & Chemicals, Inc.), F-top EF-101, EF102, EF-103, EF-104, EF-105, and EF-. 112, EF-121, EF-122A, EF-122B, EF-122C, EF-123A (manufactured by JEMCO), AK, 501 (manufactured by Neos) and the like.

Examples of commercially available perfluoroalkyl carboxylic acids include Megafac F-410 (manufactured by Dainippon Ink & Chemicals, Inc.), Ftop EF-201, EF-204 (and above, manufactured by JEMCO).
As commercial products of perfluoroalkyl group-containing phosphates, MegaFac F-493, F-494 (above, manufactured by Dainippon Ink & Chemicals, Inc.) F-top EF-123A, EF-123B, EF-125M, EF -132 (above, manufactured by JEMCO).

  Examples of the surfactant having an alkylene oxide structure include polyethylene glycol, polyether antifoaming agent, and polyether-modified silicone oil. The polyethylene glycol preferably has a number average molecular weight of 2000 or less, and the polyethylene glycol having a number average molecular weight of 2000 or less includes polyethylene glycol 2000 (number average molecular weight 2000), polyethylene glycol 600 (number average molecular weight 600), polyethylene glycol 400. (Number average molecular weight 400), polyethylene glycol 200 (number average molecular weight 200) and the like.

Moreover, as a polyether antifoamer, PE-M, PE-L (above, Wako Pure Chemical Industries Ltd. make), antifoam No. 1. Antifoaming agent No. 1 5 (above, manufactured by Kao Corporation).
Examples of the surfactant having a silicone structure include general silicone oils such as dimethyl silicone, methylphenyl silicone, diphenyl silicone, and derivatives thereof.

  Furthermore, surfactants having both a fluorine atom and an alkylene oxide structure include those having an alkylene oxide structure or a polyalkylene structure in the side chain, and the end of the alkylene oxide or polyalkylene oxide structure substituted with a substituent containing fluorine. And the like. Specific examples of the surfactant having an alkylene oxide structure include, for example, Megafac F-443, F-444, F-445, and F-446 (above, Dainippon Ink & Chemicals, Inc.), POLY FOX PF636. , PF6320, PF6520, PF656 (above, manufactured by Kitamura Chemical Co., Ltd.).

  As surfactants having both an alkylene oxide structure and a silicone structure, KF351 (A), KF352 (A), KF353 (A), KF354 (A), KF355 (A), KF615 (A), KF618, KF945 (A), KF6004 (above, manufactured by Shin-Etsu Chemical Co., Ltd.), TSF4440, TSF4445, TSF4450, TSF4446, TSF4452, TSF4453, TSF4460 (above, manufactured by GE Toshiba Silicon), BYK-300, 302, 306, 307, 310, 315, 320, 322, 323, 325, 330, 331, 333, 337, 341, 344, 345, 346, 347, 348, 370, 375, 377, 378, UV3500, UV3510, UV3570, etc. (above, Big Chemie Ja Emissions Co., Ltd.) and the like.

  The content of the surfactant is desirably 0.01% by mass or more and 1% by mass or less, and more desirably 0.02% by mass or more and 0.5% by mass or less with respect to the total solid content of the protective layer 7. When the content of the surfactant having a fluorine atom is 0.01% by mass or more, the effect of preventing coating film defects such as suppression of wrinkles and unevenness tends to increase. In addition, when the content of the surfactant having a fluorine atom is 1% by mass or less, it becomes difficult to separate the surfactant having the fluorine atom from the cured resin, and the strength of the obtained cured product tends to be maintained. is there.

  Further, the protective layer 5 may be used in combination with another coupling agent or a fluorine compound for the purpose of adjusting the film formability, flexibility, lubricity, and adhesiveness of the film. As this compound, various silane coupling agents and commercially available silicone hard coat agents are used.

  As the silane coupling agent, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, and the like are used. As a commercially available hard coat agent, KP-85, X-40-9740, X-8239 (manufactured by Shin-Etsu Silicone), AY42-440, AY42-441, AY49-208 (manufactured by Toray Dow Corning) Etc. are used. In addition, (tridecafluoro-1,1,2,2-tetrahydrooctyl) triethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, 3- (hepta) for imparting water repellency and the like. Fluoroisopropoxy) propyltriethoxysilane, 1H, 1H, 2H, 2H-perfluoroalkyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorooctyl Fluorine-containing compounds such as triethoxysilane may be added. Although the silane coupling agent is used in an arbitrary amount, the amount of the fluorine-containing compound is desirably 0.25 times or less by mass with respect to the compound not containing fluorine. If this amount is exceeded, there may be a problem with the film formability of the crosslinked film.

  Moreover, you may add resin which melt | dissolves in alcohol for the purpose of discharge gas resistance of the protective layer 5, mechanical strength, scratch resistance, particle dispersibility, viscosity control, torque reduction, wear amount control, pot life extension, and the like.

  Here, the alcohol-soluble resin means a resin that dissolves 1% by mass or more in an alcohol having 5 or less carbon atoms. Examples of resins soluble in alcohol solvents include polyvinyl butyral resins, polyvinyl formal resins, and polyvinyl acetal resins such as partially acetalized polyvinyl acetal resins in which a part of butyral is modified with formal or acetoacetal (for example, manufactured by Sekisui Chemical Co., Ltd.) ESREC B, K, etc.), polyamide resin, cellulose resin, polyvinylphenol resin and the like. In particular, polyvinyl acetal resin and polyvinyl phenol resin are desirable in terms of electrical characteristics. The resin preferably has a weight average molecular weight of 2,000 to 100,000, and more preferably 5,000 to 50,000. When the molecular weight of the resin is less than 2,000, the effect due to the addition of the resin tends to be insufficient, and when it exceeds 100,000, the solubility is reduced and the addition amount is limited. It tends to cause film formation defects. The amount of the resin added is preferably 1% by mass or more and 40% by mass or less, more preferably 1% by mass or more and 30% by mass or less, and further preferably 5% by mass or more and 20% by mass or less. If the addition amount of the resin is less than 1% by mass, the effect of the addition of the resin tends to be insufficient. If the addition amount exceeds 40% by mass, the temperature is high under high humidity (for example, 28 ° C., 85% RH). Image blur is likely to occur.

  It is desirable to add an antioxidant to the protective layer 5 for the purpose of preventing deterioration due to an oxidizing gas such as ozone generated in the charging device. When the mechanical strength of the surface of the photoconductor is increased and the photoconductor has a long life, the photoconductor is in contact with the oxidizing gas for a long time, and therefore, stronger oxidation resistance is required than before. Antioxidants are preferably hindered phenols or hindered amines, organic sulfur antioxidants, phosphite antioxidants, dithiocarbamate antioxidants, thiourea antioxidants, benzimidazole antioxidants. , Etc., may be used. The addition amount of the antioxidant is preferably 20% by mass or less, and more preferably 10% by mass or less.

  Examples of the hindered phenol antioxidant include 2,6-di-t-butyl-4-methylphenol, 2,5-di-t-butylhydroquinone, N, N′-hexamethylene bis (3,5-di). -T-butyl-4-hydroxyhydrocinnamide, 3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 2,4-bis [(octylthio) methyl] -o-cresol, 2,6-di-t-butyl-4-ethylphenol, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol) 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 2,5-di-t-amylhydroquinone, 2-t-butyl-6- (3-butyl-2- Dorokishi-5-methylbenzyl) -4-methylphenyl acrylate, 4,4'-butylidene bis (3-methyl -6-t-butylphenol) and the like.

  Furthermore, various particles may be added to the protective layer 5 for the purpose of lowering the residual potential or improving the strength. An example of the particles is silicon-containing particles. The silicon-containing particles are particles containing silicon as a constituent element, and specific examples include colloidal silica and silicone particles. Colloidal silica used as silicon-containing particles is prepared by dispersing silica having an average particle size of 1 nm to 100 nm, preferably 10 nm to 30 nm in an organic solvent such as an acidic or alkaline aqueous dispersion, alcohol, ketone, or ester. A commercially available product may be used. The solid content of colloidal silica in the protective layer 5 is not particularly limited, but 0.1% based on the total solid content of the protective layer 5 in terms of film forming properties, electrical characteristics, and strength. It is used in the range of mass% to 50 mass%, desirably 0.1 mass% to 30 mass%.

  The silicone particles used as the silicon-containing particles are selected from silicone resin particles, silicone rubber particles, and silicone surface-treated silica particles, and those commercially available are generally used. These silicone particles are spherical, and the average particle size is desirably 1 nm or more and 500 nm or less, and more desirably 10 nm or more and 100 nm or less. Silicone particles are small particles that are chemically inert and excellent in dispersibility in resins, and since the content required to obtain more sufficient properties is low, the crosslinking reaction is not hindered. The surface properties of the photographic photoreceptor are improved. In other words, it is improved in lubricity and water repellency on the surface of the electrophotographic photosensitive member in a state of being taken in without a variation in a strong cross-linked structure, and has good wear resistance and contamination resistance adhesion over a long period of time. Maintained. The content of the silicone particles in the protective layer 5 is desirably 0.1% by mass or more and 30% by mass or less, more desirably 0.5% by mass or more and 10% by mass or less, based on the total amount of the total solid content of the protective layer 5. It is.

Other particles include fluorine-based particles such as ethylene tetrafluoride, ethylene trifluoride, propylene hexafluoride, vinyl fluoride, vinylidene fluoride, and “8th Polymer Material Forum Lecture Proceedings p89”. As shown, particles made of a resin obtained by copolymerizing a fluororesin and a monomer having a hydroxyl group, ZnO—Al ₂ O ₃ , SnO ₂ —Sb ₂ O ₃ , In ₂ O ₃ —SnO ₂ , ZnO ₂ —TiO ₂ , ZnO Examples thereof include semiconductive metal oxides such as —TiO ₂ , MgO—Al ₂ O ₃ , FeO—TiO ₂ , TiO ₂ , SnO ₂ , In ₂ O ₃ , ZnO, and MgO. For the same purpose, an oil such as silicone oil may be added. Silicone oils include silicone oils such as dimethylpolysiloxane, diphenylpolysiloxane, and phenylmethylsiloxane; amino-modified polysiloxane, epoxy-modified polysiloxane, carboxyl-modified polysiloxane, carbinol-modified polysiloxane, methacryl-modified polysiloxane, mercapto-modified poly Reactive silicone oils such as siloxane and phenol-modified polysiloxane; cyclic dimethylcyclosiloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and dodecamethylcyclohexasiloxane; 1,3,5- Trimethyl-1.3.5-triphenylcyclotrisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclo Cyclic methylphenylcyclosiloxanes such as trasiloxane, 1,3,5,7,9-pentamethyl-1,3,5,7,9-pentaphenylcyclopentasiloxane; cyclic phenylcyclosiloxanes such as hexaphenylcyclotrisiloxane Fluorine-containing cyclosiloxanes such as (3,3,3-trifluoropropyl) methylcyclotrisiloxane; hydrosilyl group-containing cyclosiloxanes such as methylhydrosiloxane mixtures, pentamethylcyclopentasiloxane, and phenylhydrocyclosiloxane; penta And vinyl group-containing cyclosiloxanes such as vinylpentamethylcyclopentasiloxane.

  Further, a metal, metal oxide, carbon black, or the like may be added to the protective layer 5. Examples of the metal include aluminum, zinc, copper, chromium, nickel, silver, and stainless steel, or those obtained by depositing these metals on the surface of plastic particles. Examples of the metal oxide include zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, indium oxide doped with tin, tin oxide doped with antimony and tantalum, and zirconium oxide doped with antimony. . These may be used alone or in combination of two or more. When two or more types are used in combination, they may be simply mixed, or may be in the form of a solid solution or fusion. The average particle diameter of the conductive particles is preferably 0.3 μm or less, particularly preferably 0.1 μm or less, from the viewpoint of the transparency of the protective layer.

  In the protective layer 5, an acid catalyst is used as a curing catalyst in order to promote curing of the guanamine compound (compound represented by the general formula (A)), the melamine compound (compound represented by the general formula (B)) and the charge transport material. It may be used and cured. Acid catalysts include aliphatic carboxylic acids such as acetic acid, chloroacetic acid, trichloroacetic acid, trifluoroacetic acid, oxalic acid, maleic acid, malonic acid, and lactic acid, aromatics such as benzoic acid, phthalic acid, terephthalic acid, and trimellitic acid Carboxylic acid, methanesulfonic acid, dodecylsulfonic acid, benzenesulfonic acid, dodecylbenzenesulfonic acid, aliphatic such as naphthalenesulfonic acid, toluenesulfonic acid, and aromatic sulfonic acids are used, but sulfur-containing materials should be used. Is desirable.

  Moreover, the amount of the acid catalyst with respect to 100 parts by mass of the compound having the guanamine structure or the melamine structure is 0.1 to 50 parts by mass in that the effect that the curing of the charge transport material is promoted becomes remarkable. (10 parts by mass or more and 30 parts by mass or less is more preferable).

  By using a sulfur-containing material as a curing catalyst, this sulfur-containing material can be used as a guanamine compound (a compound represented by the general formula (A)), a melamine compound (a compound represented by the general formula (B)) or a charge transport material. The mechanical strength of the protective layer 5 obtained by exhibiting an excellent function as a curing catalyst and promoting the curing reaction is further improved. Furthermore, when the compound represented by the general formula (I) (including the general formula (II)) is used as the charge transport material, the sulfur-containing material exhibits an excellent function as a dopant for these charge transport materials. In addition, the electrical characteristics of the obtained functional layer are further improved. As a result, when an electrophotographic photosensitive member is formed, all of mechanical strength, film formability, and electrical characteristics are achieved at a high level.

  The sulfur-containing material as a curing catalyst is preferably at room temperature (for example, 25 ° C.) or exhibits acidity after heating, and at least one of organic sulfonic acid and its derivatives is most preferable from the viewpoint of adhesiveness, ghost, and electrical characteristics. desirable. The presence of these catalysts in the protective layer 5 is easily confirmed by XPS or the like.

  Examples of the organic sulfonic acid and / or a derivative thereof include p-toluenesulfonic acid, dinonylnaphthalenesulfonic acid (DNNSA), dinonylnaphthalenedisulfonic acid (DNNDSA), dodecylbenzenesulfonic acid, and phenolsulfonic acid. Among these, paratoluenesulfonic acid and dodecylbenzenesulfonic acid are desirable from the viewpoint of catalytic ability and film formability. Further, an organic sulfonate may be used as long as it can be dissociated to some extent in the curable resin composition.

  In addition, by using a so-called thermal latent catalyst that increases the catalytic ability when a temperature above a certain level is applied, the catalytic ability is low at the liquid storage temperature and the catalytic ability is high at the time of curing. And storage stability.

  As a heat latent catalyst, for example, a microcapsule in which an organic sulfone compound or the like is encapsulated in a polymer form, an adsorbed acid or the like on a pore compound such as zeolite, and a proton acid and / or proton acid derivative is blocked with a base Thermal latent proton acid catalyst, proton acid and / or proton acid derivative esterified with primary or secondary alcohol, proton acid and / or proton acid derivative blocked with vinyl ethers and / or vinyl thioethers And boron trifluoride monoethylamine complex, boron trifluoride pyridine complex, and the like.

  Among them, a product obtained by blocking a protonic acid and / or a protonic acid derivative with a base in terms of catalytic ability, storage stability, availability, and cost is desirable.

  As the protonic acid of the heat latent protonic acid catalyst, sulfuric acid, hydrochloric acid, acetic acid, formic acid, nitric acid, phosphoric acid, sulfonic acid, monocarboxylic acid, polycarboxylic acids, propionic acid, oxalic acid, benzoic acid, acrylic acid, methacrylic acid, Itaconic acid, phthalic acid, maleic acid, benzenesulfonic acid, o, m, p-toluenesulfonic acid, styrenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, decylbenzenesulfonic acid, undecylbenzenesulfonic acid, Examples include tridecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, dodecylbenzenesulfonic acid and the like. In addition, as a proton acid derivative, a neutral compound such as an alkali metal salt or alkaline earth metal circle of a proton acid such as sulfonic acid or phosphoric acid, a polymer compound in which a proton acid skeleton is introduced into a polymer chain (polyvinylsulfone) Acid, etc.). Examples of the base that blocks the protonic acid include amines.

  The amines are classified as primary, secondary or tertiary amines. There is no restriction in particular and any of them may be used.

  Examples of the primary amine include methylamine, ethylamine, propylamine, isopropylamine, n-butylamine, isobutylamine, t-butylamine, hexylamine, 2-ethylhexylamine, secondary butylamine, allylamine, and methylhexylamine.

  As secondary amines, dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, diisobutylamine, di-t-butylamine, dihexylamine, di (2-ethylhexyl) amine, N-isopropyl N-isobutylamine , Di (2-ethylhexyl) amine, disecondary butylamine, diallylamine, N-methylhexylamine, 3-pipecoline, 4-pipecoline, 2,4-lupetidine, 2,6-lupetidine, 3,5-lupetidine, morpholine, N -Methylbenzylamine and the like.

  As tertiary amines, trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, triisobutylamine, tri-t-butylamine, trihexylamine, tri (2-ethylhexyl) amine, N-methylmorpholine, N, N-dimethylallylamine, N-methyldiallylamine, triallylamine, N, N-dimethylallylamine, N, N, N ′, N′-tetramethyl-1,2-diaminoethane, N, N, N ′, N′-tetramethyl-1,3 -Diaminopropane, N, N, N ', N'-tetraallyl-1,4-diaminobutane, N-methylpiperidine, pyridine, 4-ethylpyridine, N-propyldiallylamine, 3-dimethylaminopropanol, 2-ethylpyrazine, 2, 3-di Tilpyrazine, 2,5-dimethylpyrazine, 2,4-lutidine, 2,5-lutidine, 3,4-lutidine, 3,5-lutidine, 2,4,6-collidine, 2-methyl-4-ethylpyridine, 2-methyl-5-ethylpyridine, N, N, N ′, N′-tetramethylhexamethylenediamine, N-ethyl-3-hydroxypiperidine, 3-methyl-4-ethylpyridine, 3-ethyl-4-methyl Pyridine, 4- (5-nonyl) pyridine, imidazole, N-methylpiperazine and the like can be mentioned.

  Commercially available products include “NACURE2501” (toluenesulfonic acid dissociation, methanol / isopropanol solvent, pH 6.0 to pH 7.2, dissociation temperature 80 ° C.), “NACURE2107” (p-toluenesulfonic acid dissociation, manufactured by King Industries, Inc. Isopropanol solvent, pH 8.0 to pH 9.0, dissociation temperature 90 ° C.) “NACURE 2500” (p-toluenesulfonic acid dissociation, isopropanol solvent, pH 6.0 to pH 7.0, dissociation temperature 65 ° C.), “NACURE 2530” (P-toluenesulfonic acid dissociation, methanol / isopropanol solvent, pH 5.7 to pH 6.5, dissociation temperature 65 ° C.), “NACURE2547” (p-toluenesulfonic acid dissociation, aqueous solution, pH 8.0 to pH 9.0, Dissociation temperature 107 ), “NACURE2558” (p-toluenesulfonic acid dissociation, ethylene glycol solvent, pH 3.5 to pH4.5, dissociation temperature 80 ° C.), “NACUREXP-357” (p-toluenesulfonic acid dissociation, methanol solvent, pH 2. 0 to pH 4.0, dissociation temperature 65 ° C.) “NACUREXP-386” (p-toluenesulfonic acid dissociation, aqueous solution, pH 6.1 to pH 6.4, dissociation temperature 80 ° C.), “NACUREX C-2211” (p -Toluenesulfonic acid dissociation, pH 7.2 to pH 8.5, dissociation temperature 80 ° C.), “NACURE 5225” (dodecylbenzenesulfonic acid dissociation, isopropanol solvent, pH 6.0 to pH 7.0, dissociation temperature 120 ° C.), “ NACURE 5414 "(dodecylbenzenesulfonic acid dissociation, key Ren solvent, dissociation temperature 120 ° C.), “NACURE 5528” (dodecylbenzenesulfonic acid dissociation, isopropanol solvent, pH 7.0 to pH 8.0, dissociation temperature 120 ° C.), “NACURE 5925” (dodecylbenzenesulfonic acid dissociation, pH 7.0) PH 7.5 or less, dissociation temperature 130 ° C., “NACURE 1323” (disinyl naphthalene sulfonic acid dissociation, xylene solvent, pH 6.8 to pH 7.5, dissociation temperature 150 ° C.), “NACURE 1419” (dinonyl naphthalene sulfonic acid Dissociation, xylene / methyl isobutyl ketone solvent, dissociation temperature 150 ° C.), “NACURE1557” (dinonylnaphthalenesulfonic acid dissociation, butanol / 2-butoxyethanol solvent, pH 6.5 to pH 7.5, dissociation temperature 150 ° C.), “ NA CUREX 49-110 ”(dinonyl naphthalene disulfonic acid dissociation, isobutanol / isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 90 ° C.),“ NACURE 3525 ”(dinonyl naphthalene disulfonic acid dissociation, isobutanol / isopropanol solvent, pH 7.0 to pH 8.5, dissociation temperature 120 ° C., “NACUREXP-383” (dinonyl naphthalene disulfonic acid dissociation, xylene solvent, dissociation temperature 120 ° C.), “NACURE 3327” (dinonyl naphthalene disulfonic acid dissociation, isobutanol / Isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 150 ° C.), “NACURE4167” (phosphoric acid dissociation, isopropanol / isobutanol solvent, pH 6.8 to pH 7.3, dissociation temperature 80 ), “NACUREXP-297” (phosphoric acid dissociation, water / isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 90 ° C., “NACURE 4575” (phosphoric acid dissociation, pH 7.0 to pH 8.0, dissociation temperature) 110 ° C.).

  These thermal latent catalysts may be used alone or in combination of two or more.

  Here, the compounding amount of the catalyst is at least one amount selected from the guanamine compound (the compound represented by the general formula (A)) and the melamine compound (the compound represented by the general formula (B)) (in the coating solution). The solid content concentration is preferably in the range of 0.1% by mass to 50% by mass, and more preferably 10% by mass to 30% by mass. When the amount is less than the above range, the catalytic activity may be too low, and when it exceeds the above range, the light resistance may be deteriorated. The light resistance refers to a phenomenon in which the irradiated portion causes a decrease in density when the photosensitive layer is exposed to light from the outside such as room light. The cause is not clear, but it is presumed that this is because a phenomenon similar to the optical memory effect occurs as disclosed in JP-A-5-099737.

  The protective layer 5 having the above configuration includes at least one selected from the guanamine compound (the compound represented by the general formula (A)) and the melamine compound (the compound represented by the general formula (B)) and the specific charge transport. It forms using the coating liquid for film formation containing at least 1 sort (s) of a conductive material. In the coating liquid for film formation, the constituent components of the protective layer 5 are added as necessary.

  The coating solution for film formation is prepared without a solvent or, if necessary, alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran, diethyl ether and dioxane. You may carry out using solvents, such as. Such solvents can be used singly or in combination of two or more, and preferably have a boiling point of 100 ° C. or lower. As the solvent, it is particularly preferable to use a solvent having at least one hydroxyl group (for example, alcohol).

  The amount of the solvent is arbitrarily set, but if it is too small, the guanamine compound (the compound represented by the general formula (A)) and the melamine compound (the compound represented by the general formula (B)) are likely to be precipitated. 0.5 parts by mass or more and 30 parts by mass or less, preferably 1 part by mass of at least one kind selected from a compound represented by formula (A) and a melamine compound (compound represented by formula (B)) 1 to 20 parts by mass is used.

  In addition, when the coating liquid is obtained by reacting the above components, it may be simply mixed and dissolved, but it is room temperature (for example, 25 ° C.) to 100 ° C., preferably 30 ° C. to 80 ° C. for 10 minutes to 100 Heating may be performed for a period of time or less, preferably 1 hour or more and 50 hours or less. It is also desirable to irradiate ultrasonic waves at this time. Thereby, it is likely that a partial reaction proceeds, and it is easy to obtain a film having no coating film defects and little variation in film thickness.

  Then, a coating solution for forming a film is formed on the charge transport layer 3 by a usual method such as a blade coating method, a Mayer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method. The protective layer 5 can be obtained by curing by applying at a temperature of, for example, 100 ° C. or more and 170 or less if necessary.

  The coating liquid for forming a film is used for, for example, an antistatic film on a fluorescent coloring paint, a glass surface, a plastic surface, etc., in addition to the use as a photoreceptor. When this coating liquid for forming a film is used, a film having excellent adhesion to the lower layer is formed, and performance deterioration due to repeated use over a long period is suppressed.

  Here, the electrophotographic photoreceptor has been described as an example of the function separation type, but the content of the charge generation material in the single-layer type photosensitive layer 6 (charge generation / charge transport layer) is 10% by mass or more and 85% by mass. % Or less, desirably 20 mass% or more and 50 mass% or less. In addition, the content of the charge transport material is desirably 5% by mass or more and 50% by mass or less. The method for forming the single-layer type photosensitive layer 6 (charge generation / charge transport layer) is the same as the method for forming the charge generation layer 2 and the charge transport layer 3. The film thickness of the single-layer type photosensitive layer (charge generation / charge transport layer) 6 is preferably about 5 μm to 50 μm, and more preferably 10 μm to 40 μm.

  In the embodiment, at least one selected from a guanamine compound (a compound represented by the general formula (A)) and a melamine compound (a compound represented by the general formula (B)) and a specific charge transporting material (general Although the form using the crosslinked product with the compound represented by the formula (I) for the protective layer 5 has been described, in the case of a layer configuration without the protective layer 5, for example, it is used for the charge transport layer located in the outermost surface layer. May be.

As the charging device 8, for example, a contact type using a charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube, or the like that is conductive or semiconductive (volume resistivity is 10 ³ Ωcm or more and 10 ¹⁰ Ωcm or less). A charger is used. In addition, known chargers such as a non-contact type roller charger, a scorotron charger using a non-contact type corona discharge, a corotron charger, and the like are also used. In the present embodiment, a non-contact charging device (charging means) such as a scorotron charger is desirable because it can be operated at high speed and charging uniformity can be obtained. As the scorotron charger, a known material such as a tungsten wire or a stainless steel wire is used. For the wire, other materials such as gold, silver, platinum, nickel, glass, and carbon may be coated or subjected to acid value prevention treatment. The diameter of the wire is preferably 30 μm or more and 80 μm or less. In addition, a scorotron charger having a plurality of wires is appropriately selected. If the diameter of the wire is less than 30 μm, there may be a problem in durability, and it may be difficult to use for a charger that is used for a long period of time as in this embodiment, and if it exceeds 80 μm, the surface area of the wire Since it becomes too large, discharge unevenness is likely to occur, it is difficult to obtain uniform charging characteristics for a long time, and it may be difficult to use for a charger that is used for a long time as in this embodiment.

  The potential unevenness removing device 15 may be provided on the downstream side of the transfer device 40 in the rotation direction of the electrophotographic photoreceptor 7, and may be provided on either the upstream side or the downstream side of the cleaning device 13. Absent. As the potential unevenness removing device, either a scorotron charging member using corona discharge or a corotron charging member may be used. Even if it is repeatedly used over a long period of time, the electrophotographic photosensitive member will not be poorly charged and image defects ( A non-contact charging member such as a corotron charging member is desirable in that the effect that image ghost) is suppressed and a stable image can be obtained becomes remarkable. Further, it is desirable that the potential unevenness removing device 15 applies the surface of the electrophotographic photosensitive member 7 by superimposing the AC voltage on the DC voltage in that the effect of the present embodiment becomes more remarkable. The application conditions are selected according to the surface potential of the electrophotographic photoreceptor 7, the toner charging conditions, and the primary transfer conditions. For example, when the potential unevenness removing device 15 is a corotron charging member, the AC applied voltage is preferably used in the range of −10 KVpp to −1 KVpp, and the frequency is preferably used in the range of 300 Hz to 900 Hz. In general, it is desirable to use a DC applied voltage in a range of −800 μA to −20 μA. Regarding the above parameters, it is desirable not to discharge the electrophotographic photosensitive member during actual use, and this is selected in consideration of this point.

  Although not shown, a photosensitive member heating member for increasing the temperature of the electrophotographic photosensitive member 7 and reducing the relative temperature is provided around the electrophotographic photosensitive member 7 for the purpose of improving the stability of the image. Also good.

  Examples of the exposure apparatus 9 include optical system devices that expose the surface of the photoconductor 7 with light such as semiconductor laser light, LED light, and liquid crystal shutter light in a desired image-like manner. The wavelength of the light source is in the spectral sensitivity region of the photoreceptor. As the wavelength of the semiconductor laser, near infrared having an oscillation wavelength near 780 nm is the mainstream. However, the present invention is not limited to this wavelength, and an oscillation wavelength laser in the 600 nm range or a laser having an oscillation wavelength in the vicinity of 400 nm to 450 nm as a blue laser may be used. For color image formation, a surface-emitting laser light source capable of multi-beam output is also effective.

  As the developing device 11, for example, a general developing device that performs development by bringing a magnetic or non-magnetic one-component developer or a two-component developer into contact or non-contact may be used. The developing device is not particularly limited as long as it has the functions described above, and is selected according to the purpose. For example, a known developing device having a function of attaching the one-component developer or the two-component developer to the photoreceptor 7 using a brush, a roller, or the like can be used. Among these, those using a developing roller holding the developer on the surface are desirable.

Hereinafter, the toner used in the developing device 11 will be described.
The toner used in the image forming apparatus according to the present embodiment has an average shape factor (shape factor: (ML ² / A) × (π / 4) × 100) from the viewpoint of obtaining high developability and transferability and high image quality. The number average, where ML represents the maximum length of the particles, and A represents the projected area of the particles) is preferably 100 or more and 150 or less, more preferably 105 or more and 145 or less, and more preferably 110 or more and 140 or less. It is further desirable that Further, the toner preferably has a volume average particle diameter of 3 μm or more and 12 μm or less, more preferably 3.5 μm or more and 10 μm or less, and further preferably 4 μm or more and 9 μm or less. By using a toner that satisfies this average shape factor and volume average particle diameter, the developability and transferability are improved, and a so-called high-quality image called photographic image quality is obtained.

  The toner is not particularly limited by the production method as long as it satisfies the above average shape factor and volume average particle diameter. For example, the toner may include a binder resin, a colorant, a release agent, and the like. A kneading and pulverizing method in which a charge control agent is added, kneading, pulverizing, and classifying; a method in which the shape of particles obtained by the kneading and pulverizing method is changed by mechanical impact force or thermal energy; Emulsion polymerization of the body, and the resulting dispersion is mixed with a dispersion of a colorant, a release agent and, if necessary, a charge control agent, and then agglomerated and heat-fused to obtain toner particles. Suspension polymerization method in which a polymerizable monomer for obtaining a binder resin, a colorant, a release agent, and a charge control agent, if necessary, are suspended in an aqueous solvent and polymerized; A water-based solution of a resin, a colorant, a release agent, and a solution such as a charge control agent as necessary. Toner is used which is suspended in and produced by a dissolution suspension method in which granulated.

  Further, a known method such as a production method in which the toner obtained by the above method is used as a core, and agglomerated particles are further adhered and heat-fused to give a core-shell structure is used. The toner production method is preferably a suspension polymerization method, an emulsion polymerization aggregation method, or a dissolution suspension method in which an aqueous solvent is used from the viewpoint of shape control and particle size distribution control, and an emulsion polymerization aggregation method is particularly desirable.

  The toner base particles are composed of a binder resin, a colorant, and a release agent, and include silica and a charge control agent as necessary.

  Binder resins used for toner base particles include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, etc. Α-methylene aliphatics such as vinyl esters, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate Homopolymers and copolymers of monocarboxylic acid esters, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl butyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone Polyester resins by copolymerization of dicarboxylic acids and diols.

  Particularly representative binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, and styrene-maleic anhydride copolymer. A polymer, polyethylene, a polypropylene, a polyester resin etc. are mentioned. Further, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like can be mentioned.

  In addition, as colorants, magnetic powders such as magnetite and ferrite, carbon black, aniline blue, caryl blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, Lamp Black, Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 is exemplified as a representative example.

  Typical examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, Fischer tropical wax, montan wax, carnauba wax, rice wax, and candelilla wax.

  As the charge control agent, known ones are used, and azo metal complex compounds, metal complex compounds of salicylic acid, and resin type charge control agents containing polar groups are used. When the toner is manufactured by a wet manufacturing method, it is desirable to use a material that is difficult to dissolve in water in terms of controlling ionic strength and reducing wastewater contamination. The toner may be either a magnetic toner containing a magnetic material or a non-magnetic toner containing no magnetic material.

  As the toner used in the developing device 11, the toner base particles and the external additive are mixed with a Henschel mixer or a V blender.

Manufactured by mixing. In addition, when the toner base particles are produced by a wet method, external addition can also be performed by a wet method.

  Lubricating particles may be added to the toner used in the developing device 11. Lubricating particles include solid lubricants such as graphite, molybdenum disulfide, talc, fatty acids and fatty acid metal salts, low molecular weight polyolefins such as polypropylene, polyethylene and polybutene, silicones having a softening point upon heating, oleic amides , Erucic acid amide, ricinoleic acid amide, stearic acid amide and other aliphatic amides, carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil and other plant waxes, beeswax animal wax, montan wax, ozokerite , Ceresin, paraffin wax, microcrystalline wax, mineral such as Fischer-Tropsch wax, petroleum wax, and modified products thereof. These are used individually by 1 type or in combination of 2 or more types. However, the average particle size is preferably in the range of 0.1 μm or more and 10 μm or less, and those having the above chemical structure may be pulverized to make the particle sizes uniform. The amount added to the toner is desirably in the range of 0.05% by mass to 2.0% by mass, and more desirably in the range of 0.1% by mass to 1.5% by mass.

  To the toner used in the developing device 11, inorganic particles, organic particles, composite particles obtained by attaching inorganic particles to the organic particles, and the like may be added for the purpose of removing deposits and deteriorated materials on the surface of the electrophotographic photosensitive member. .

  Inorganic particles include silica, alumina, titania, zirconia, barium titanate, aluminum titanate, strontium titanate, magnesium titanate, zinc oxide, chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, Various inorganic oxides such as manganese oxide, boron oxide, silicon carbide, boron carbide, titanium carbide, silicon nitride, titanium nitride, and boron nitride, nitrides, borides, and the like are preferably used.

  In addition, the inorganic particles may be mixed with titanium coupling agents such as tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, bis (dioctylpyrophosphate) oxyacetate titanate, γ- (2- Aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxy Silane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane The treatment may be performed with a silane coupling agent such as run, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, and p-methylphenyltrimethoxysilane. In addition, those hydrophobized with higher fatty acid metal salts such as silicone oil, aluminum stearate, zinc stearate, calcium stearate and the like are also desirably used.

  Examples of the organic particles include styrene resin particles, styrene acrylic resin particles, polyester resin particles, and urethane resin particles.

  The particle diameter is preferably 5 nm to 1000 nm, more preferably 5 nm to 800 nm, and even more preferably 5 nm to 700 nm in terms of number average particle diameter. If the average particle size is less than the lower limit, the polishing ability tends to be lacking. On the other hand, if the average particle size exceeds the upper limit, the surface of the electrophotographic photoreceptor tends to be damaged. Moreover, it is desirable that the sum of the addition amounts of the above-described particles and the lubricating particles is 0.6% by mass or more.

  Other inorganic oxides added to the toner are small-diameter inorganic oxides with a primary particle size of 40 nm or less for powder flowability, charge control, etc. It is desirable to add a larger diameter inorganic oxide. Known inorganic oxide particles are used, but it is desirable to use silica and titanium oxide in combination for precise charge control.

Further, the surface treatment of the small-diameter inorganic particles increases the dispersibility and increases the effect of increasing the powder fluidity. Furthermore, it is desirable to add carbonates such as calcium carbonate and magnesium carbonate and inorganic minerals such as hydrotalcite in order to remove the discharge purified product.

  In addition, the color toner for electrophotography is used by mixing with a carrier. As the carrier, iron powder, glass beads, ferrite powder, nickel powder, or those coated with a resin are used. The mixing ratio with the carrier is set.

  As the transfer device 40, for example, a contact transfer charger using a belt, a roller, a film, a rubber blade, etc., a known transfer charger such as a scorotron transfer charger using a corona discharge or a corotron transfer charger is used. Can be mentioned.

  As the intermediate transfer member 50, a belt-like member (intermediate transfer belt) made of polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber or the like having semiconductivity is used. Further, as the form of the intermediate transfer member 50, a drum-like one is used in addition to the belt shape.

  In addition to the above-described devices, the image forming apparatus 100 may include, for example, a light neutralizing device that performs light neutralization on the photoconductor 7.

  FIG. 2 is a schematic cross-sectional view showing an image forming apparatus according to another embodiment. As shown in FIG. 2, the image forming apparatus 120 is a tandem-type full-color image forming apparatus in which four process cartridges 300 are mounted. In the image forming apparatus 120, four process cartridges 300 are arranged in parallel on the intermediate transfer member 50, and one electrophotographic photosensitive member is used for one color. The image forming apparatus 120 has the same configuration as that of the image forming apparatus 100 except that it is a tandem system.

  When the electrophotographic photosensitive member of the present invention is used in a tandem type image forming apparatus, the electric characteristics of the four photosensitive members are stabilized, so that an image quality with excellent color balance can be obtained over a longer period.

  Further, in the image forming apparatus (process cartridge) according to the present embodiment, the developing device (developing means) is a developer holder that moves (rotates) in the opposite direction to the moving direction (rotating direction) of the electrophotographic photosensitive member. It is desirable to have a developing roller that is Here, the developing roller has a cylindrical developing sleeve that holds developer on the surface, and the developing device has a configuration that includes a regulating member that regulates the amount of developer supplied to the developing sleeve. Can be mentioned. By moving (rotating) the developing roller of the developing device in a direction opposite to the rotation direction of the electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member is rubbed with toner that is caught between the developing roller and the electrophotographic photosensitive member. Is done. And this rubbing, at least one selected from a guanamine compound (compound represented by the general formula (A)) and a melamine compound (compound represented by the general formula (B)) and a specific charge transporting material (particularly The discharge product adhered to the surface of the electrophotographic photosensitive member due to the deposit removability enhanced by the cross-linked product with the material that increases the number of reactive functional groups to obtain a cured film having a high cross-linking density as described above. In particular, it is considered that the scraping property of the low resistance substance due to ozone and NOx is improved, and the deposition of such discharge products is suppressed for a very long time. As a result, it is presumed that the occurrence of image quality defects peculiar to a high wear-resistant photoconductor such as a reduction in resolution, streaks, and image blur is suppressed, and higher image quality and longer life are achieved at a higher level. Moreover, it is considered that excellent slipperiness of the electrophotographic photosensitive member surface is maintained over a long period of time by suppressing the accumulation of discharge products. As a result, the cleaning blade can be prevented from turning over or generating abnormal noise, and a high level of cleaning performance can be maintained over a long period of time.

In the image forming apparatus according to the present embodiment, the distance between the developing sleeve and the photoconductor is preferably 200 μm or more and 600 μm or less, and more preferably 300 μm or more, from the viewpoint of suppressing the accumulation of discharge products over a longer period. More preferably, it is 500 μm or less. From the same point of view, the distance between the developing sleeve and the regulating blade, which is a regulating member that regulates the developer amount, is desirably 300 μm or more and 1000 μm or less, and more desirably 400 μm or more and 750 μm or less.
Further, from the viewpoint of suppressing the accumulation of discharge products over a longer period, the absolute value of the moving speed of the developing roll surface is 1.5 times or more the absolute value (process speed) of the moving speed of the photoreceptor surface. Desirably, it is 5 times or less, and more desirably 1.7 times or more and 2.0 times or less.

  Further, in the image forming apparatus (process cartridge) according to the present embodiment, the developing device (developing unit) includes a developer holding body having a magnetic material, and is a two-component developer containing a magnetic carrier and toner. It is desirable to develop an image. In this configuration, a clearer image quality can be obtained with a color image, and higher image quality and longer life can be achieved compared to the case of a one-component developer, particularly a non-magnetic one-component developer.

  The image forming apparatus (process cartridge) according to the present embodiment is capable of suppressing the image defects (image ghosts) and maintaining the effect of stably obtaining an image, while being operated at high speed. The peripheral speed at the time of image formation is desirably 300 mm / sec or more and 340 mm / sec or less, and more desirably 310 mm / sec or more and 320 mm / sec or less. Here, the peripheral speed when the electrophotographic photosensitive member 7 forms an image is calculated from the diameter of the electrophotographic photosensitive member and the rotational speed of the motor for driving the photosensitive member. The rotation speed of the motor is measured using a general tachometer or the like.

  Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

[Production of photoconductor]
-Production of photoreceptor 1-
First, a 60 mmφ cylindrical aluminum base material subjected to a honing treatment was prepared. Next, 20 parts by mass of a zirconium compound (trade name: Orgatics ZC540, manufactured by Matsumoto Pharmaceutical Co., Ltd.), 2.5 parts by mass of a silane compound (trade name: A1100, manufactured by Nihon Unicar Co., Ltd.), polyvinyl butyral resin (trade name: 3 parts by mass of Eslex BM-S (manufactured by Sekisui Chemical Co., Ltd.) and 45 parts by mass of butanol were mixed to obtain a coating solution for forming an undercoat layer. This coating solution was dip-coated on an aluminum substrate and dried by heating at 145 ° C. for 10 minutes to form an undercoat layer of 1.5 μm.

  Next, chlorogallium phthalocyanine having strong diffraction peaks at Bragg angles (2θ ± 0.2 °) of 7.4 °, 16.6 °, 25.5 ° and 28.3 ° in the X-ray diffraction spectrum is 1 1 part by mass and 1 part by mass of polyvinyl butyral (trade name: ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.) and 100 parts by mass of n-butyl acetate are further mixed with glass beads for 1 hour with a paint shaker and dispersed. Thus, a coating solution for forming a charge generation layer was obtained. This coating solution was dip-coated on the undercoat layer and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.10 μm.

  Next, 2.5 parts by mass of a charge transport material represented by the following formula (CT-1) and a polymer compound having a structural unit represented by the following formula (B-1) (n is the number of repetitions. Viscosity average (Molecular weight: 60000) 2.5 parts by mass and 20 parts by mass of chlorobenzene were mixed to obtain a coating solution for forming a charge transport layer.

  This charge transport layer forming coating solution was applied onto the charge generation layer by a dip coating method and heated at 135 ° C. for 40 minutes to form a charge transport layer having a thickness of 15 μm. Thus, the charge generation layer and the charge transport layer were formed on the aluminum substrate.

  Next, 0.09 part by mass of a guanamine compound “Nicalac MW-30 (manufactured by Nippon Carbide)” as a resin, 99 parts by mass of the exemplified compound I-30 as a charge transporting material, and a p-toluenesulfonic acid catalyst Was dissolved in cyclopentanol to obtain a coating solution for forming a protective layer. This coating solution was applied onto the charge transport layer by a dip coating method and air-dried at 25 ° C. for 30 minutes. Then, it hardened | cured by heat-processing at 160 degreeC for 1 hour, and formed the protective layer with a film thickness of 4.5 micrometers. This photoreceptor was designated as an electrophotographic photoreceptor 1.

-Production of electrophotographic photoreceptors 2 to 70-
In the preparation of a coating solution for forming a protective layer in the production of the electrophotographic photoreceptor 1, the type and amount of charge transporting material, the type and amount of guanamine compound and melamine compound, and the use of a catalyst (p-toluenesulfonic acid catalyst) The electrophotographic photoreceptors 2 to 70 were produced by changing the amounts as described in Tables 1 and 2. The photoreceptors 66 and 67 used the same amounts of the guanamine compound and the melamine compound, and the photoreceptors 43 to 63 used the same amount of the exemplified compound: I-30 and the exemplified compound: I-28. Moreover, the unit of the usage-amount in Table 1 and Table 2 is a mass part.

The following potential unevenness removing device was prepared as potential unevenness removing means.
-Potential unevenness removal device 1: Corotron device AC application -9.0 KVpp frequency 700 Hz, DC application -200 μA (constant current control)
-Potential unevenness removal device 2: Corotron device DC application-400 μA (constant current control)

<Examples 1 to 56, Comparative Examples 1 to 22>
A photoreceptor shown in Tables 3 and 4 and a potential unevenness removing device ("-" means unused) are combined with a color laser printer (Fuji Xerox Co., Ltd., "Docu Center II 7550I" modified machine, intermediate (Equipped with a transfer member) (potential unevenness removal device is attached downstream of the transfer device and upstream of the toner removal device) and forms an image on the condition that the peripheral speed when forming an image on the electrophotographic photosensitive member is 320 mm / sec. The following evaluation was conducted. The results are shown in Tables 3 and 4.

(Initial electrical characteristics)
Evaluation was performed using a surface potential meter 344 manufactured by Trek Co., Ltd. for charging characteristics (charging potential), surface potential wrinkle preparation, and residual potential, which are electrical characteristics of the photoreceptor when mounted on the printer.
◎: There is no problem in electrical characteristics, and there is no problem in use in a high-quality region. ○: There is no problem in electrical characteristics, there is no problem in actual use. △: There is a problem in potential gradation of electrical characteristics. : Cannot withstand actual use

(Image density unevenness)
After the evaluation of the initial electrical characteristics, the image density unevenness of a 20% halftone image formed under a general environment (22 ° C., 50% RH) was visually evaluated according to the following criteria.
A: There is no density unevenness, and there is no problem in use in a high-quality area.
○: Density unevenness occurs slightly, but there is no problem in actual use.
Δ: Density unevenness occurs and the problem is confirmed.
X: The density unevenness is so intense that it cannot withstand actual use.

(Cleanability)
After the above evaluation of the image density unevenness, 600,000 continuous images of area coverage 5% documents were formed on A4 paper in a general environment (22 ° C., 50% RH), and further low temperature and low humidity (10 ° C., 10% % RH), 10 sheets of non-transferred images of 100% density on the entire surface were output on A3 paper, and the cleaning property was visually evaluated according to the following criteria.
A: No toner slipping is confirmed.
○: No toner slip-through is confirmed at output up to 20 sheets.
Δ: Partially passing through the toner is observed, but there is no practical problem.
X: Toner slippage is observed over the entire surface.

(Image flow)
After the above evaluation of the cleaning property, the product is further stored at high temperature and high humidity (30 ° C., 90% RH) for 8 hours, and after storage, a 1 dot Line image is formed. From the reproducibility of the 1 dot Line image, the image flow is based on the following criteria. Visual evaluation was made.
A: 1 dot Line is resolved.
○: 1 dot Line is slightly blurred but there is no problem in actual use.
Δ: 1 dot Line is crushed.
X: 1 dot Line has partially disappeared.

(ghost)
After the image flow evaluation described above, the ghost of the first image and the 1000th image was visually evaluated according to the following criteria after standing still for 24 hours under low temperature and low humidity (10 ° C., 15% RH).
(Double-circle): There is no generation | occurrence | production of a ghost and there is no problem in the use in a high quality area | region.
○: There is a slight occurrence of ghost, but there is no problem in actual use.
Δ: Strongly ghosted and a problem is confirmed.
X: Ghosting is intense and cannot be used in actual use.

Those described as “not evaluated” in Tables 3 and 4 were not evaluated for the following reasons.
When the initial electrical characteristics were “x”, the characteristics of the photoconductor were not satisfied, so that an image could not be formed, and subsequent evaluation was impossible.
When the cleaning property was “x”, no image could be formed in the image flow evaluation, and the subsequent evaluation (including ghost) became impossible.

  As shown in Tables 3 and 4, in the example, compared to the comparative example, the occurrence of ghost is suppressed, and the image density unevenness due to charging failure in high speed use is suppressed. In addition, it has excellent initial electrical characteristics, and it has been improved significantly for cleaning performance and image flow for long-term output of 600,000 sheets continuously, and high quality and high image quality can be obtained over a long period of time.

DESCRIPTION OF SYMBOLS 1 Subbing layer 2 Charge generation layer 3 Charge transport layer 4 Conductive substrate 5 Protective layer 6 Single layer type photosensitive layer 7 Electrophotographic photoreceptor 8 Charging device 9 Exposure device 11 Developing device 13 Cleaning device 14 Lubricant 15 Potential unevenness removing means 40 Transfer device 50 Intermediate transfer body 100 Image forming device 120 Image forming device 132 Fibrous member (roll shape)
133 Fibrous member (flat brush shape)

Claims (9)

Formed on the electrophotographic photosensitive member; an electrophotographic photosensitive member; a charging unit that charges the electrophotographic photosensitive member; an electrostatic latent image forming unit that forms an electrostatic latent image on the charged electrophotographic photosensitive member; Developing means for developing the electrostatic latent image to form a toner image; transfer means for transferring the toner image to the transfer target; and the potential of the electrophotographic photosensitive member surface after the toner image is transferred to the transfer target A potential unevenness removing means for removing unevenness; and a toner removing means for removing residual toner on the surface of the electrophotographic photosensitive member after the toner image is transferred to the transfer body,
The electrophotographic photosensitive member has a conductive substrate and a photosensitive layer provided on the surface of the conductive substrate, and the outermost surface layer of the photosensitive layer is at least one selected from a guanamine compound and a melamine compound; , —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH, and at least one charge transporting material having at least one selected from a substituent as a substituent. The content in the outermost surface layer of at least one kind selected from the guanamine compound and the melamine compound is 0.1% by mass or more and 5% by mass or less, and the content in the outermost surface layer of the charge transporting material Is 95% by mass or more and 99% by mass or less.   The image forming apparatus according to claim 1, wherein the charging unit is a non-contact type charging unit.   3. The image according to claim 1, wherein the potential unevenness removing unit is a non-contact charging member, and an AC voltage is superimposed on a DC voltage to apply the surface of the electrophotographic photosensitive member. Forming equipment.   The image forming apparatus according to any one of claims 1 to 3, wherein a peripheral speed at the time of image formation of the electrophotographic photosensitive member is 300 mm / sec or more and 340 mm / sec or less. The outermost surface layer of the photosensitive layer is substituted with at least one selected from a guanamine compound and a melamine compound and at least one selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. 5. The image forming apparatus according to claim 1, wherein at least one kind of the charge transporting material possessed as a material is cured using an acid catalyst. The image forming apparatus according to claim 5, wherein an amount of the acid catalyst with respect to 100 parts by mass of the compound having the guanamine structure or the melamine structure is 0.1 parts by mass or more and 50 parts by mass or less. The image forming apparatus according to claim 1, wherein the charge transporting material is a compound represented by the following general formula (I).
_{F - ((- R 1 -X} ) n1 R 2 -Y) n2 (I)
(In general formula (I), F is an organic group derived from a compound having a hole transporting ability, R ₁ and R ₂ are each independently a linear or branched alkylene group having 1 to 5 carbon atoms. , N1 represents 0 or 1, n2 represents an integer of 1 to 4, X represents oxygen, NH, or a sulfur atom, Y represents —OH, —OCH ₃ , —NH ₂ , —SH, and — Indicates either COOH.)   8. The process cartridge according to claim 1, wherein at least the electrophotographic photosensitive member, the charging unit, the potential unevenness removing unit, and the toner removing unit are integrated into an image forming apparatus. The image forming apparatus according to any one of the above. Removes at least the electrophotographic photosensitive member, charging means for charging the electrophotographic photosensitive member, and uneven charging on the surface of the electrophotographic photosensitive member after the toner image is transferred to the transfer target. Potential unevenness removing means to perform, and toner removing means for removing residual toner on the surface of the electrophotographic photosensitive member after the toner image is transferred to the transfer target,
The electrophotographic photoreceptor includes a conductive substrate and a photosensitive layer provided on the surface of the conductive substrate, and the outermost surface layer of the photosensitive layer is at least one selected from a guanamine compound and a melamine compound; , —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH, and at least one charge transporting material having at least one substituent selected from —COOH, and In the outermost surface layer of the charge transporting material, the content in the outermost surface layer of at least one selected from the guanamine compound and the melamine compound is 0.1% by mass or more and 5% by mass or less. A process cartridge having a content of 95% by mass or more and 99% by mass or less.