JP2005227396A - Image forming method, image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method in which occurrence of image defects due to pinhole leak of an electrophotographic photoreceptor is suppressed and by which good image quality can stably be obtained over a prolonged period of time, and to provide an image forming apparatus and a process cartridge. <P>SOLUTION: The image forming method comprises an electrifying step of electrifying an electrophotographic photoreceptor comprising a conductive substrate, an undercoat layer and a photosensitive layer; an exposure step of forming an electrostatic latent image on the photoreceptor by exposing the electrified photoreceptor; a developing step of forming a toner image by developing the electrostatic latent image with a developer; a transfer step of transferring the toner image from the photoreceptor onto a transfer medium; and a cleaning step of removing the toner remaining on the photoreceptor after the transfer step, wherein the thickness of the undercoat layer and volume resistivity satisfy conditions represented by the expression (1): log<SB>10</SB>(ρ)>-3×log<SB>10</SB>(d)+13 [where ρ represents the volume resistivity (Ω cm); and d represents the thickness (μm) of the undercoat layer]. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  An electrophotographic image forming apparatus in which processes such as charging, exposure, development, and transfer are performed using an electrophotographic photosensitive member can perform image formation at high speed and obtain high print quality. Used in the fields of machine and laser beam printer.

In such an image forming apparatus, the demand for higher image quality has been increasing recently. Therefore, in order to meet such demands, the use of polymerized toner has been proposed in order to reduce the particle size of the toner used in the developer and to make the particle size distribution and shape uniform. In the case of using a polymerized toner, since the cleaning property when removing the residual toner from the electrophotographic photosensitive member after transfer is liable to be impaired, a technique using a specific cleaning device (for example, to maintain the cleaning property) , See Patent Document 1) and the like.
JP 2003-122039 A

  As described in Patent Document 1 and the like, many cleaning devices have a cleaning blade. However, in order to obtain a desired cleaning property, the cleaning blade is applied to the electrophotographic photosensitive member at a relatively high linear pressure. It is necessary to abut. At this time, if foreign matter or dust adheres to the surface of the electrophotographic photosensitive member, the foreign matter or the like is strongly pressed against the surface of the photosensitive member by the cleaning blade and penetrates into the photosensitive layer. Then, when the electrophotographic photosensitive member in which foreign matter or the like penetrates is used in the next image forming process, an electrical pinhole is generated by applying a high electric field locally by a charging device, thereby causing image quality defects. .

  As a method of suppressing such electrical leakage, there is a method of providing an undercoat layer between a conductive substrate constituting an electrophotographic photosensitive member and a photosensitive layer, and it is particularly effective to increase the thickness of the undercoat layer. It is believed that there is. However, in the above method, in order to improve the repetitive stability and environmental stability of the electrophotographic photosensitive member, to prevent image quality defects, etc., there is a function (charge blocking function) for suppressing charge injection required for the undercoat layer. The function of adjusting electrical resistance (resistance adjusting function) is impaired. For example, if the thickness of the undercoat layer is simply increased, the electrical resistance in the thickness direction becomes excessively large, and the electrical characteristics required in the image forming process are degraded. There is also a method of reducing the electrical resistance of the undercoat layer by adding conductive powder to the undercoat layer, but even in this method, both the charge blocking function and the resistance adjusting function are well balanced in the undercoat layer. It is not always easy to give.

  The present invention has been made in view of such circumstances, and can sufficiently suppress image quality defects caused by pinhole leakage of an electrophotographic photosensitive member, and can stably obtain good image quality over a long period of time. An object is to provide an image forming method, an image forming apparatus, and a process cartridge.

In order to solve the above problems, an image forming method of the present invention comprises a conductive substrate, an undercoat layer formed on the conductive substrate, and an electrophotographic photoreceptor having a photosensitive layer formed on the undercoat layer. A charging step for charging the photosensitive member, an exposure step for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image on the electrophotographic photosensitive member, and developing the electrostatic latent image with a developer to form a toner image. A developing step, a transfer step for transferring the toner image from the electrophotographic photosensitive member to a transfer medium, and a cleaning step for removing the toner remaining on the electrophotographic photosensitive member after the transfer step. The film thickness and the volume resistivity satisfy the condition represented by the following formula (1).
log ₁₀ (ρ)> − 3 · log ₁₀ (d) +13 (1)
[In the formula (1), ρ represents volume resistivity (Ω · cm), and d represents the film thickness (μm) of the undercoat layer. ]

  As described above, in the image forming method in which the steps of charging, exposure, development, transfer, and cleaning are performed, the film thickness and volume resistivity of the undercoat layer satisfy the condition represented by the above formula (1). While maintaining the charge blocking function and resistance adjustment function of the undercoat layer at a high level, the occurrence of image defects due to electrical leakage of the electrophotographic photosensitive member is sufficiently suppressed, so that good image quality is stable over a long period of time. Can be obtained.

Further, the image forming apparatus of the present invention includes a conductive substrate, an undercoat layer formed on the conductive substrate, an electrophotographic photoreceptor having a photosensitive layer formed on the undercoat layer, and an electrophotographic photoreceptor. A charging device for charging the photosensitive member, an exposure device for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image on the electrophotographic photosensitive member, and developing the electrostatic latent image with a developer to form a toner image. A developing device; a transfer device that transfers a toner image from the electrophotographic photosensitive member to a transfer medium; and a cleaning device that removes toner remaining on the electrophotographic photosensitive member after transfer. And the volume resistivity satisfies the condition represented by the following formula (1).
log ₁₀ (ρ)> − 3 · log ₁₀ (d) +13 (1)
[In the formula (1), ρ represents volume resistivity (Ω · cm), and d represents the film thickness (μm) of the undercoat layer. ]

  According to the image forming apparatus of the present invention, the occurrence of image defects due to pinhole leakage of the electrophotographic photosensitive member is sufficiently suppressed while maintaining the charge blocking function and the resistance adjusting function of the undercoat layer at a high level. The image forming method of the present invention that can be performed can be effectively carried out.

In the present invention, the undercoat layer is surface-treated using a silane coupling agent having at least a structure in which an amino group is bonded to the carbon atom at the end of the molecular chain, and satisfies the condition represented by the following formula (2). It is preferable to contain metal oxide particles.
(I ₁ / I ₂ ) ≦ 1.0 (2)
[In formula (2), I ₁ represents the absorption intensity in the characteristic absorption band 3270 cm ⁻¹ of the infrared absorption spectrum of the metal oxide particles obtained after the surface treatment, and I ₂ represents the metal oxide particles obtained after the surface treatment. The absorption intensity in the characteristic absorption band 880 cm ⁻¹ of the infrared absorption spectrum is represented. ]

  By including the specific metal oxide particles in the undercoat layer, it becomes easy to control the film thickness and volume resistivity of the undercoat layer in order to satisfy the above formula (1). All of the resistance adjustment function and the electrical leakage suppression function can be provided in a balanced manner.

  Here, the silane coupling agent used for the surface treatment is preferably a fluorine-free compound. The metal oxide particles preferably contain at least one selected from zinc oxide, titanium oxide and tin oxide.

  Moreover, it is preferable that the film thickness of an undercoat layer is larger than 15 micrometers. As a result, it is possible to more reliably prevent electrical leakage due to penetration of the foreign material and dust into the photosensitive layer and the undercoat layer. In this case as well, the film thickness and volume resistivity of the undercoat layer satisfy the condition represented by the above formula (1), thereby sufficiently suppressing the charge blocking function and resistance adjustment function of the undercoat layer. be able to.

  In the present invention, it is preferable that the electrophotographic photoreceptor contains lubricating particles (more preferably fluorine resin particles) in a layer disposed on the side of the photosensitive layer farthest from the conductive substrate.

  In the present invention, the developer contains toner particles having a volume average particle diameter of 3 to 9 μm obtained by a polymerization method, and the cleaning device contacts the electrophotographic photosensitive member at a linear pressure of 10 to 150 g / cm. It is preferable to have a blade member. This suppresses the phenomenon that the toner slips between the electrophotographic photosensitive member and the blade member in the cleaning process (slip-through) and the phenomenon that the blade presses the electrophotographic photosensitive member into the film (toner filming). Thus, the cleaning property can be improved. Also in this case, the charge blocking function, the resistance adjusting function, and the electrical leakage suppressing ability of the undercoat layer can be achieved by satisfying the conditions expressed by the above formula (1) for the film thickness and volume resistivity of the undercoat layer. It can be maintained sufficiently.

The process cartridge of the present invention comprises a conductive substrate, an undercoat layer formed on the conductive substrate, an electrophotographic photoreceptor having a photosensitive layer formed on the undercoat layer, and an electrophotographic photoreceptor. And a charging device for charging, wherein the thickness and volume resistivity of the undercoat layer satisfy a condition represented by the following formula (1).
log ₁₀ (ρ)> − 3 · log ₁₀ (d) +13 (1)
[In the formula (1), ρ represents volume resistivity (Ω · cm), and d represents the film thickness (μm) of the undercoat layer. ]

  According to the process cartridge of the present invention, the thickness of the undercoat layer and the volume resistivity satisfy the conditions represented by the above formula (1), so that charge blocking of the undercoat layer is possible in electrophotographic image formation. Since the occurrence of image defects due to electrical leakage of the electrophotographic photosensitive member is sufficiently suppressed while maintaining the function and the resistance adjustment function at a high level, it is possible to obtain good image quality over a long period of time.

  According to the image forming method, the image forming apparatus, and the process cartridge of the present invention, it is possible to sufficiently suppress the image quality defect due to the pinhole leak of the electrophotographic photosensitive member and stably obtain a good image quality over a long period of time. Become.

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

  FIG. 1 is a schematic diagram showing a preferred embodiment of the image forming apparatus of the present invention. An image forming apparatus 100 shown in FIG. 1 includes a drum-shaped (cylindrical) electrophotographic photosensitive member 1 that is rotatably provided. Around the electrophotographic photoreceptor 1, along the movement direction of the outer peripheral surface of the photoreceptor 1, a charging device 3, an exposure device 5, a developing device 7, a transfer device 9, a cleaning device 11, and a static eliminator (erasing device). 13 are arranged in this order. The electrophotographic photoreceptor 1 has a conductive substrate, an undercoat layer formed on the conductive substrate, and a photosensitive layer formed on the undercoat layer.

In the image forming apparatus 100 including the electrophotographic photosensitive member 1, the film thickness and volume resistivity of the undercoat layer satisfy the condition represented by the following formula (1).
log ₁₀ (ρ)> − 3 · log ₁₀ (d) +13 (1)
[In the formula (1), ρ represents volume resistivity (Ω · cm), and d represents the film thickness (μm) of the undercoat layer. ]

  The charging device 3 is a corona charging type charging device and charges the electrophotographic photosensitive member 1. Examples of the charging device 3 include a corotron charger and a scorotron charger. The charging device 3 is connected to a power source 15.

  The exposure device 5 exposes the charged electrophotographic photosensitive member 1 to form an electrostatic latent image on the electrophotographic photosensitive member 1.

  The developing device 7 develops the electrostatic latent image with a developer to form a toner image. The developer preferably contains toner particles having a volume average particle diameter of 3 to 9 μm obtained by a polymerization method.

  The transfer device 9 transfers the toner image developed on the electrophotographic photosensitive member 1 to a transfer medium.

  The cleaning device 11 removes toner remaining on the electrophotographic photosensitive member 1 after transfer. The cleaning device 11 preferably has a blade member that comes into contact with the electrophotographic photosensitive member 1 at a linear pressure of 10 to 150 g / cm.

  The static eliminator (erase device) 13 erases the remaining charge of the electrophotographic photosensitive member 1.

  Further, the image forming apparatus 100 includes a fixing device 15 that fixes the toner image on the transfer medium after the transfer process.

  Next, the electrophotographic photoreceptor 1 will be described in detail. FIG. 2 is a schematic cross-sectional view showing an example of the electrophotographic photosensitive member according to the present invention. The electrophotographic photoreceptor 1 has a structure in which an undercoat layer 22, an intermediate layer 23, a photosensitive layer 24, and a protective layer 25 are sequentially laminated on a conductive substrate 21. The electrophotographic photoreceptor 1 shown in FIG. 2 is a function separation type photoreceptor, and the photosensitive layer 24 includes a charge generation layer 26 and a charge transport layer 27.

With reference to FIG. 2, each element of the electrophotographic photoreceptor 1 will be described in detail.
As the conductive substrate 21, a metal drum such as aluminum, copper, iron, stainless steel, zinc, nickel, etc .; on a substrate such as sheet, paper, plastic, glass, etc., aluminum, copper, gold, silver, platinum, palladium, titanium, Deposited metal such as nickel-chromium, stainless steel, copper and indium, or deposited conductive metal compound such as indium oxide and tin oxide; laminated metal foil on the above substrate or carbon black, oxidized Indium, tin oxide, antimony oxide powder, metal powder, copper iodide, and the like are dispersed in a binder resin, and subjected to a conductive treatment by coating it.

  The shape of the conductive substrate 21 is not limited to a drum shape, and may be a sheet shape or a plate shape. In the case where a metal pipe is used as the conductive substrate 21, the surface may remain as it is, and before that, processing such as mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, wet honing, etc. May be performed.

  The undercoat layer 22 has a function of preventing charge injection from the conductive substrate 21 to the photosensitive layer 24 when the photosensitive layer 24 is charged. The undercoat layer 22 also functions as an adhesive layer that allows the photosensitive layer 24 to be bonded and held integrally with the conductive substrate 21. Further, the undercoat layer 22 has a function of preventing light reflection of the conductive substrate 21.

  The undercoat layer 22 only needs to have a film thickness and a volume resistivity that satisfy the condition of the above formula (1). The undercoat layer 22 preferably includes metal oxide particles and a binder resin, which will be described later.

  When the thickness of the undercoat layer 22 is as thick as possible, it is easy to prevent the entry of foreign matter from the outside, and the leak resistance is improved. Accordingly, the thickness of the undercoat layer 22 is preferably larger than 15 μm. On the other hand, a thin film having a film thickness of, for example, 15 μm or less tends to have insufficient leak resistance. From the viewpoint of enhancing the leak resistance of the undercoat layer 22 and effectively preventing the occurrence of pinhole leak, the thickness of the undercoat layer 22 is more preferably 15 μm to 50 μm, and further preferably 20 to 50 μm. preferable.

  Here, if the thickness of the undercoat layer 22 exceeds 50 μm, it becomes difficult to maintain good dispersibility of the contained material such as metal oxide particles, and there is a tendency that image quality is deteriorated due to an increase in residual charges. In this case, it is also difficult to make the film thickness uniform, and the manufacturing cost may increase.

  However, if the film has sufficient leakage resistance and the occurrence of the above-described leakage defect is not a concern, the thickness of the undercoat layer 22 can be set to be thinner than 15 μm. Applicable to thin films of about 1 μm.

Subbing layer 22 is necessary to obtain an appropriate resistance for the leakage acquired resistance, therefore, it is preferable that the volume resistivity of the undercoat layer 22 is ^{10 4 ~10 13 Ω · cm,} 10 8 ~ 10 ¹³ Ω · cm is more preferable, and 10 ⁹ to 10 ¹² Ω · cm is still more preferable. If the volume resistivity is less than 10 ⁴ Ω · cm, it tends to be difficult to obtain sufficient leakage resistance. On the other hand, if it exceeds 10 ¹³ Ω · cm, the residual potential tends to increase. The volume resistivity of the undercoat layer 22 can be controlled by changing the electrical resistance value of the metal oxide particles themselves and the amount added, and changing the dispersion state of the metal oxide particles in the binder resin. .

The metal oxide particles contained in the undercoat layer 22 preferably have a powder resistance (volume resistivity) of about 10 ² to 10 ¹¹ Ω · cm. If the resistance value of the metal oxide particles is lower than 10 ² Ω · cm, sufficient leak resistance tends to be difficult to obtain. On the other hand, if the resistance value of the metal oxide particles is higher than 10 ¹¹ Ω · cm, the residual potential may be increased.

  Moreover, the particle | grains in which a metal oxide particle contains at least 1 sort (s) chosen from a zinc oxide, a titanium oxide, and a tin oxide are preferable. Among these, particles containing zinc oxide are more preferable, and particles containing zinc oxide as a main component are more preferable. Here, “particles mainly composed of zinc oxide” refers to particles having a zinc oxide content of 90% by mass or more based on the total mass of the particles.

  The metal oxide particles may be surface-treated. In addition, two or more kinds of metal oxide particles such as those having different surface treatments or particles having different particle diameters can be mixed and used.

The metal oxide particles preferably have a specific surface area of 10 m ² / g or more. Those having a specific surface area value of 10 m ² / g or less tend to cause a decrease in chargeability and tend to make it difficult to obtain good electrophotographic characteristics.

  The surface treatment agent for the metal oxide particles may be any material as long as desired characteristics can be obtained, and can be selected from known materials. Examples thereof include silane coupling agents, titanate coupling agents, aluminum coupling agents, and surfactants. In particular, a silane coupling agent is preferably used because good electrophotographic characteristics can be obtained. Furthermore, a silane coupling agent having an amino group is preferably used because it gives a good blocking property to the undercoat layer.

  Any silane coupling agent having an amino group can be used as long as it can obtain desired photoreceptor characteristics. Specifically, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N -Bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane and the like are exemplified, but not limited thereto.

  Two or more silane coupling agents can be used in combination. Examples of the silane coupling agent that can 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-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltri Examples include methoxysilane. The present invention is not limited to, et al.

  As the surface treatment method, any known method can be used, but a dry method or a wet method can be used.

  When surface treatment is performed by a dry method, a silane coupling agent dissolved directly or in an organic solvent is dropped and sprayed with dry air or nitrogen gas while stirring the metal oxide particles with a mixer having a large shearing force. By making it, a metal oxide particle can be processed uniformly. The addition or spraying is preferably performed at a temperature below the boiling point of the solvent. Spraying at a temperature above the boiling point of the solvent is not preferred because the solvent evaporates before the metal oxide particles are uniformly treated, and the silane coupling agent is locally concentrated, making uniform treatment difficult. . After addition or spraying, baking is preferably performed at 100 ° C. or higher. Baking can be 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, the metal oxide particles are dispersed in a solvent by stirring or ultrasonic waves, or using a sand mill, attritor, ball mill, etc., and after adding or stirring or dispersing the silane coupling agent solution, the solvent is removed. Is processed uniformly. The solvent is distilled off by filtration or distillation. After removing the solvent, baking is preferably performed at 100 ° C. or higher. Baking can be 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, the moisture contained in the metal oxide particles can be removed before adding the surface treatment agent. Specific examples thereof include a method of removing metal oxide particles while stirring and heating in a solvent used for surface treatment, and a method of removing by azeotropy with a solvent.

Among the metal oxide particles described above, the metal oxide particles are surface-treated using a silane coupling agent having at least a structure in which an amino group is bonded to the carbon atom at the end of the molecular chain. Metal oxide particles satisfying the conditions represented are preferred.
(I ₁ / I ₂ ) ≦ 1.0 (2)
[In formula (2), I ₁ represents the absorption intensity in the characteristic absorption band 3270 cm ⁻¹ of the infrared absorption spectrum of the metal oxide particles obtained after the surface treatment, and I ₂ represents the metal oxide particles obtained after the surface treatment. The absorption intensity in the characteristic absorption band 880 cm ⁻¹ of the infrared absorption spectrum is represented. ]

Here, “infrared absorption spectrum of metal oxide particles” indicates an infrared absorption spectrum measured based on the KBr tablet method. “Absorption intensity” indicates the percent transmittance (% T) of infrared light. T represents the transmittance (T = P / P ₀ , P: incident light intensity, P ₀ : transmitted light intensity transmitted through the KBr tablet of the measurement sample).

The value of (I ₁ / I ₂ ) is a value that correlates with the amount of amino groups bonded to the surface of the metal oxide particles (after the surface treatment). As this value increases, the amount of amino groups bonded to the surface of the metal oxide particles (after the surface treatment) also increases.

  Hereafter, the manufacturing method of the metal oxide particle which satisfy | fills the said Formula (2) is demonstrated. In the present specification, a surface using a silane coupling agent having at least a structure in which an amino group is bonded to the carbon atom at the end of the molecular chain (hereinafter simply referred to as “silane coupling agent C” if necessary). The metal oxide particles after the treatment are referred to as “metal oxide particles A”. Further, the metal oxide particles before the surface treatment is performed on the metal oxide particles A are referred to as “metal oxide particles B”. Therefore, the metal oxide particle A is a particle in a state where a film made of a silane coupling agent having an amino group as a raw material is formed on a part or all of the surface of the metal oxide particle B.

  The metal oxide particles B are surface-treated using a silane coupling agent C, and the obtained metal oxide particles A have amino groups on the surface in an amount satisfying the condition represented by the above (2). By including the metal oxide particles A, it is possible to form the undercoat layer 22 that has an excellent blocking (charge injection control) function and has a sufficiently reduced variation in resistance value (film resistance value) during repeated use. it can. That is, the undercoat layer 22 having excellent charge characteristics with little charge accumulation can be formed. Furthermore, by using this undercoat layer 22, it is possible to easily and reliably constitute an electrophotographic photosensitive member having high durability and high image quality that can sufficiently prevent deterioration in electrical characteristics due to repeated use. it can.

  Metal oxide particles having a surface treated with the above-mentioned silane coupling agent C and having an amino group on the surface in an amount satisfying the condition represented by the above formula (2) among the obtained metal oxide particles A Although the detailed mechanism about the fact that the excellent undercoat layer 22 having a small charge accumulation property due to repeated use can be constituted by selectively containing only A has not been clearly clarified, the present inventors Thinks as follows.

  That is, the present inventors compared the silane compound (here, a compound having no amino group at the terminal carbon atom of the molecular chain, particularly a fluorine-containing silane compound) with a silane coupling agent C. It is considered that the charge blocking performance of the undercoat layer 22 can be improved by using (surface treatment with a silane coupling agent having at least a structure in which an amino group is bonded to the carbon atom at the end of the molecular chain). Yes. In particular, when a fluorine-containing silane compound is used for the surface treatment, the dispersibility tends to deteriorate. Therefore, the silane coupling agent C is preferably a fluorine-free compound.

Here, if (I ₁ / I ₂ ) exceeds 1.0, the deterioration of the electric characteristics of the electrophotographic photosensitive member during repeated use cannot be sufficiently prevented, and image quality defects such as density reduction occur. It tends to be easier. On the other hand, if (I ₁ / I ₂ ) is too small, amino groups on the surface of the metal oxide particles A are insufficient, and sufficient charge blocking performance cannot be obtained, and the chargeability tends to decrease. is there. Therefore, (I ₁ / I ₂ ) is more preferably 0.2 to 1.0.

  Moreover, as a method of obtaining the metal oxide particles A satisfying the condition of the above formula (2), there are a method of controlling the amount of the silane coupling agent used for the surface treatment, and an extra silane by washing with a solvent after the surface treatment. Examples thereof include a method for removing the coupling agent and a method for appropriately decomposing amino groups by heat treatment after the surface treatment. Thus, since the metal oxide particles A satisfying the above condition (2) can be obtained relatively easily, also from this point of view, the undercoat layer 22 is sufficiently prevented from being deteriorated in electrical characteristics due to repeated use. Can be configured easily.

  Furthermore, since the metal oxide particles A are contained in the undercoat layer 22 and the environmental fluctuation of the film resistance value of the undercoat layer 22 can be sufficiently suppressed, the thickness of the undercoat layer 22 is increased (hereinafter referred to as “undercoat layer 22”). Can be easily made thicker). For example, the thickness of the undercoat layer 22 can be adjusted to be larger than 15 μm, for example.

  As the metal oxide particles B, the same types as those of the above-described suitable metal oxide particles can be used. The particle size of the metal oxide particles B can provide desired characteristics and can be dispersed in the coating solution for forming the undercoat layer. The coating solution for forming the undercoat layer is applied to the conductive substrate 21. Any particle size can be used as long as it can be applied on the surface and the thickness of the undercoat layer 22 or less, but the average particle size is preferably 100 nm or less. In addition, a particle size here means an average primary particle size.

  Further, regarding the powder resistance value (volume resistivity) and the specific surface area of the metal oxide particles B, it is preferable to take the same values as those of the above-described suitable metal oxide particles.

  The metal oxide particles B are surface-treated with a silane coupling agent C to form metal oxide particles A. Metal oxide particles A are obtained by surface treatment, and by selectively containing particles satisfying the condition of formula (2), the blocking (charge injection control) function of the undercoat layer 22 is improved, and resistance during repeated use The fluctuation amount of the value (film resistance value) can be sufficiently reduced.

  Here, the surface treatment refers to a treatment in which the silane coupling agent C is adsorbed on the surface of the metal oxide particles B and the hydrolyzable characteristic group of the silane coupling agent C is hydrolyzed there.

  The silane coupling agent C is not particularly limited as long as it is a silane coupling agent having at least a structure in which an amino group is bonded to the terminal carbon atom of the molecular chain, but is preferably a fluorine-free compound, A compound having a structure in which a fluorine atom or an atomic group containing a fluorine atom (characteristic group) is not bonded to a terminal carbon atom is more preferable.

  Specific examples of the silane coupling agent C include the same silane coupling agents having an amino group as described above. Such silane coupling agent C can also be used in an arbitrary mixture of two or more.

  Moreover, as a silane coupling agent that can be used in combination with the silane coupling agent C in the surface treatment, a silane coupling agent that can be used in combination with the above-described silane coupling agent having an amino group is used. Can be mentioned.

  Next, a surface treatment method for the metal oxide particles B will be described. The method for surface treatment of the metal oxide particles B with the silane coupling agent C is not particularly limited, and for example, a known method such as a dry method, a wet method, or a gas phase method can be used.

  In addition, you may isolate | separate the metal oxide particle A which satisfy | fills the conditions of Formula (2) from the metal oxide particle A obtained after surface-treating the metal oxide particle B. However, when the surface treatment conditions of the metal oxide particles B with good reproducibility for obtaining the metal oxide particles A satisfying the condition of the formula (2) can be easily optimized and grasped in advance, All of the metal oxide particles A obtained by the optimized surface treatment conditions of the metal oxide particles B may be used for forming the undercoat layer 22.

  For example, among the above-mentioned metal oxide particles A, a method for obtaining those satisfying the formula (2) includes a method for controlling the amount of the silane coupling agent for surface treatment, and washing with a solvent after the surface treatment. Examples thereof include a method for removing excess silane coupling agent, a method for appropriately decomposing amino groups by heat treatment after the surface treatment, and the like. For example, the amount of silane coupling agent C used is the combination of silane coupling agent C and metal oxide particles B used for the surface treatment, the temperature of the surface treatment reaction, the apparatus used for the surface treatment and the metal oxide to be prepared. It can be optimized and set according to the surface treatment conditions such as the scale of the particle A.

  For example, an example of a procedure for performing surface treatment based on a dry method will be described. First, a silane coupling agent (a silane coupling agent C or a mixture obtained by adding a silane coupling agent that can be used in combination with the silane coupling agent C) is adsorbed on the surface of the metal oxide particles B. At this time, while stirring the metal oxide particles B with a mixer having a large shearing force, the silane coupling agent is sprayed with dry air or nitrogen gas, or the silane coupling agent is used as a solvent (organic solvent, water, etc.). The dissolved liquid is sprayed with dry air or nitrogen gas. Thereby, the silane coupling agent (the mixture which added the silane coupling agent C mentioned above or the silane coupling agent which can be used together previously) to the surface of the metal oxide particle B can be adsorbed uniformly.

  When the silane coupling agent C is adsorbed on the surface of the metal oxide particles B (at the time of spraying), it is preferable to perform the temperature near the boiling point of the solvent when using the solvent. Spraying at a temperature equal to or higher than the boiling point of the solvent is not preferred because the solvent evaporates before being stirred uniformly, and the silane coupling agent tends to accumulate locally, making uniform treatment difficult.

  Then, after that, a baking process may be performed. Thereby, the hydrolysis reaction of the silane coupling agent (the silane coupling agent C or a mixture in which the silane coupling agent that can be used in combination with the silane coupling agent is added) can sufficiently proceed. The baking treatment can be performed under any temperature condition as long as the desired electrophotographic characteristics can be obtained. However, the silane coupling agent (silane coupling agent C or the silane cup that can be used in combination with the silane coupling agent C described above) can be used. When a mixture to which a ring agent is added is used, it is preferably performed at a temperature of 100 ° C. or higher, more preferably at a temperature of 150 to 250 ° C. If it is lower than 150 ° C., the hydrolysis reaction of the silane coupling agent C may not be sufficiently advanced. If the temperature exceeds 250 ° C., the silane coupling agent (the silane coupling agent C or a mixture to which the silane coupling agent that can be used in combination with the silane coupling agent is added) may be decomposed.

  Next, the surface-treated metal oxide particles A are crushed as necessary. Thereby, since the aggregate of the metal oxide particles A can be crushed, the dispersibility of the metal oxide particles A in the undercoat layer 22 can be improved.

  Next, an example of a procedure for performing a surface treatment based on a wet method will be described. First, the metal oxide particles B are dispersed in a solvent using ultrasonic waves, a sand mill, an attritor, a ball mill, or the like. Next, a liquid containing the silane coupling agent (the silane coupling agent C or a mixture containing the silane coupling agent that can be used in combination with the silane coupling agent) is added and stirred to advance the surface treatment reaction. . Thereafter, the solvent is distilled off from this liquid by distillation. Here, it is also conceivable to perform a solvent removal method by filtration. However, in this method, the unreacted silane coupling agent (the silane coupling agent C or a mixture to which the silane coupling agent that can be used in combination with the silane coupling agent is added) easily flows out, so as to obtain desired characteristics. This is not preferable because the amount of the silane coupling agent (the silane coupling agent C or a mixture to which the silane coupling agent that can be used in combination with the silane coupling agent is added) tends to be difficult to control.

  Moreover, you may further perform the baking process similar to the dry method mentioned above with respect to the solid substance obtained after solvent removal. In the wet method, the surface adsorbed water of the metal oxide particles B may be removed before the surface treatment. Examples of the method for removing the surface adsorbed water include a method of removing the surface adsorbed water while stirring and heating in a solvent used for the surface treatment, and a method of removing it by azeotroping with the solvent.

  As described above, the metal oxide particles satisfying the condition of the above formula (2) are manufactured. When the metal oxide particles are surface-treated with a silane coupling agent (including a silane coupling agent having at least a structure in which an amino group is bonded to the carbon atom at the end of the molecular chain), the metal in the undercoat layer 22 The amount of the silane coupling agent relative to the oxide particles can be arbitrarily set as long as desired electrophotographic characteristics can be obtained.

  Next, the binder resin contained in the undercoat layer 22 will be described. Binder resins include acetal resins such as polyvinyl butyral, 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. -Known polymer resin compounds such as vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol resin, phenol-formaldehyde resin, melamine resin, urethane resin, and charge transport resin having a charge transport group Or conductive resin such as polyaniline can be used.

  Among them, a resin insoluble in the upper coating solvent is preferably used, and in particular, an acetal resin, a phenol resin, a phenol-formaldehyde resin, a melamine resin, a urethane resin, an epoxy resin, and the like are preferably used.

  The undercoat layer 22 can be formed using an undercoat layer forming coating solution containing the metal oxide particles and the binder resin described above. The ratio between the metal oxide particles and the binder resin in the coating solution for forming the undercoat layer can be arbitrarily set within a range where desired electrophotographic characteristics can be obtained.

  Various additives can be used in the coating liquid for forming the undercoat layer in order to improve electrical characteristics, environmental stability, and image quality.

  Additives include quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, fluorenones such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone Compounds, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole and 2,5-bis (4-naphthyl) -1,3,4-oxadi Azoles, oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5′-tetra- Electron transport materials such as diphenoquinone compounds such as t-butyldiphenoquinone, electron transport pigments such as polycyclic condensation systems and azo systems, zirconium chelate compounds, Hexafluorophosphate chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, there can be used a known material such as a silane coupling agent.

  The silane coupling agent is used for the surface treatment of the metal oxide, but may be added to the coating solution as an additive. Specific examples of the silane coupling agent include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and γ-glycidoxy. Propyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) ) -Γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, and the like.

  Specific examples of the zirconium chelate compound include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl zirconium acetoacetate, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate , Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

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

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

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

  As a solvent for preparing the coating solution for forming the undercoat layer, a known organic solvent can be used. For example, the solvent can be arbitrarily selected from solvents such as alcohols, aromatics, halogenated hydrocarbons, ketones, ketone alcohols, ethers and esters. More specifically, 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 can be used.

  These solvent can be used individually by 1 type 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 a mixed solvent.

  Examples of the method for dispersing the metal oxide particles include a method using a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker. The undercoat layer 22 is formed on the conductive substrate 21 using the coating solution for forming the undercoat layer thus obtained. As a coating method for forming the undercoat layer 22, a normal method such as a blade coating method, a wire 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. be able to.

  The undercoat layer 22 preferably has a Vickers strength of 35 or more.

  The surface roughness of the undercoat layer 22 is adjusted to ¼n (n is the refractive index of the upper layer) to ½λ of the exposure laser wavelength λ used to prevent moire images. Resin particles can be added to the undercoat layer 22 to adjust the surface roughness. As the resin particles, silicone resin particles, cross-linked PMMA resin particles, and the like can be used.

  Further, the undercoat layer 22 can be polished for adjusting the surface roughness. Examples of the polishing method include a method using buffing, sand blasting, wet honing, grinding, and the like.

  The intermediate layer 23 is provided between the undercoat layer 22 and the photosensitive layer 24 in order to improve electrical characteristics, improve image quality, improve image quality maintenance, improve adhesion to the photosensitive layer 24, and the like.

  The intermediate layer 23 includes a binder resin and an organometallic compound. Examples of the binder resin include acetal resins such as polyvinyl butyral, 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. -High molecular resin compounds such as vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin. These can be used individually by 1 type or as a mixture or polycondensate of 2 or more types. Examples of the organometallic compound include organometallic compounds containing zirconium, titanium, aluminum, manganese, silicon, and the like. These can be used individually by 1 type or as a mixture or polycondensate of 2 or more types.

  As the organometallic compound, an organometallic compound containing zirconium or silicon is preferable. The organometallic compound is excellent in performance such as a low residual potential, a small potential change due to the environment, and a small potential change due to repeated use.

  Specific examples of the silicon compound include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltri Methoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl)- Examples include γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, and the like.

  Particularly preferably used silicon compounds include vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 2- (3,4-epoxy. (Cyclohexyl) ethyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N Examples include silane coupling agents such as phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane.

  Specific examples of the organic zirconium compound include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate , Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Specific examples of the organic titanium compound include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, and titanium lactate ammonium. Examples thereof include salts, titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.

  Specific examples of the organoaluminum compound include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.

  The intermediate layer 23 plays the role of an electrical blocking layer in addition to improving the coatability of the upper layer. However, when the film thickness is too large, the electrical barrier becomes too strong and the potential increases due to desensitization or repetition. May cause. Therefore, the film thickness of the intermediate layer 23 is preferably 0.1 to 3 μm.

  The charge generation layer 26 includes a charge generation material. That is, the charge generation layer 26 is formed by vacuum deposition of a charge generation material, or is formed using a charge generation layer forming coating solution containing an organic solvent and a binder resin.

  As the charge generation material, a known charge generation material can be used. For infrared light, phthalocyanine pigments, squarylium, bisazo, trisazo, perylene, dithioketopyrrolopyrrole can be used. For visible light, condensed polycyclic pigments, bisazo, perylene, trigonal selenium, dye-sensitized zinc oxide fine particles, and the like can be used. Among these, phthalocyanine pigments are preferable because particularly excellent performance can be obtained. By using a phthalocyanine pigment, an electrophotographic photoreceptor having particularly high sensitivity and excellent repeat stability can be obtained.

  Phthalocyanine pigments generally have several crystal forms, and any of these crystal forms can be used as long as it is a crystal form capable of obtaining the desired sensitivity. Particularly preferred phthalocyanine pigments include chlorogallium phthalocyanine, dichlorosus phthalocyanine, hydroxygallium phthalocyanine, metal-free phthalocyanine, oxytitanyl phthalocyanine, and chloroindium phthalocyanine.

  The phthalocyanine pigment crystal is obtained by mechanically dry-grinding a phthalocyanine pigment produced by a known method with an automatic mortar, planetary mill, vibration mill, CF mill, roller mill, sand mill, kneader, or the like, or after such dry grinding. It can manufacture by performing a wet grinding process using a ball mill, a mortar, a sand mill, a kneader, etc. with a solvent.

  Solvents used in the wet grinding treatment include aromatics (toluene, chlorobenzene, etc.), amides (dimethylformamide, N-methylpyrrolidone, etc.), aliphatic alcohols (methanol, ethanol, butanol, etc.), aliphatic poly Monohydric alcohols (ethylene glycol, glycerin, polyethylene glycol, etc.), aromatic alcohols (benzyl alcohol, phenethyl alcohol, etc.), esters (acetic ester, butyl acetate, etc.), ketones (acetone, methyl ethyl ketone, etc.), dimethyl sulfoxide, And ethers (diethyl ether, tetrahydrofuran, etc.). Also, a mixed system of two or more of these, or a mixed system of these organic solvents and water may be used.

  The amount of the solvent used is preferably 1 to 200 parts by weight and more preferably 10 to 100 parts by weight with respect to 1 part by weight of the pigment crystal. The treatment temperature is preferably from −20 ° C. to the boiling point of the solvent, more preferably from −10 to 60 ° C. In addition, grinding aids such as sodium chloride and sodium nitrate can be used during grinding. The grinding aid is preferably used in a weight of 0.5 to 20 times, more preferably 1 to 10 times the weight of the pigment.

  In addition, phthalocyanine pigment crystals produced by a known method can be crystal controlled by treating with acid pasting or a combination of acid pasting and dry pulverization or wet pulverization as described above. . The acid used for acid pasting is preferably sulfuric acid, more preferably 70 to 100% sulfuric acid, and even more preferably 95 to 100% sulfuric acid. The melting temperature is preferably -20 to 100 ° C, more preferably -10 to 60 ° C. The amount of concentrated sulfuric acid is set in the range of 1 to 100 times, preferably 3 to 50 times the weight of the phthalocyanine pigment crystals.

  As the solvent to be precipitated, water or a mixed solvent of water and an organic solvent is used in an arbitrary amount. There are no particular restrictions on the temperature conditions for precipitation, but cooling with ice or the like is preferred to prevent heat generation.

  The charge generation material can be subjected to a surface treatment to improve the stability of electrical characteristics, prevent image quality defects, and the like. As the surface treatment agent, a coupling agent or the like can be used, but is not limited thereto. Specific examples of the coupling agent used for the surface treatment 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-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane and the like can be mentioned.

  Particularly preferred silane coupling agents are vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4 -Epoxycyclohexyl) ethyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane and the like.

  Zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate zirconium butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, zirconium naphthenate, lauric acid Organic zirconium compounds such as zirconium, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like can also be used.

  Tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, titanium lactate, titanium lactate Organic titanium compounds such as ethyl ester, titanium triethanolamate, polyhydroxytitanium stearate, aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) An organoaluminum compound such as can also be used.

  The binder resin can be selected from a wide range of insulating resins, and can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. Preferred binder resins include polyvinyl acetal resin, polyarylate resin (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin Insulating resins such as polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin can be mentioned, but are not limited thereto. These binder resins can be used individually by 1 type or in mixture of 2 or more types. Of these, polyvinyl acetal resin is particularly preferably used.

  In the coating solution for forming a charge generation layer, the blending ratio (weight ratio) between the charge generation material and the binder resin is preferably in the range of 10: 1 to 1:10. The solvent for preparing the coating solution can be arbitrarily selected from known organic solvents such as alcohols, aromatics, halogenated hydrocarbons, ketones, ketone alcohols, ethers, esters, and the like. . For example, 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, dioxane, tetrahydrofuran, Usual organic solvents such as methylene chloride, chloroform, chlorobenzene, and toluene can be used.

  These solvent can be used individually by 1 type 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 a mixed solvent.

  Various additives may be added to the coating solution for forming the charge generation layer in order to improve electrical characteristics and image quality. Additives include quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, fluorenones such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone Compounds, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole and 2,5-bis (4-naphthyl) -1,3,4-oxadi Azoles, oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5′-tetra- Electron transport materials such as diphenoquinone compounds such as t-butyldiphenoquinone, electron transport pigments such as polycyclic condensation systems and azo systems, zirconium chelate compounds, Hexafluorophosphate chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, there can be used a known material such as a silane coupling agent.

  Specific examples of the silane coupling agent include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and γ-glycidoxy. Propyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) ) -Γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, and the like.

  Specific examples of the zirconium chelate compound include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl zirconium acetoacetate, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate , Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

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

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

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

  Examples of a method for dispersing the above-described materials in the coating solution include a method using a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker.

  In this dispersion, when the above-mentioned material is in the form of particles, it is preferable that the particles have a particle size of preferably 0.5 μm or less, more preferably 0.3 μm or less, and further preferably 0.15 μm or less. It is effective for improving sex.

  As a coating method used when the charge generation layer 26 is provided, a normal method such as a blade coating method, a wire 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. be able to.

  The thickness of the charge generation layer 26 is preferably 0.05 to 5 μm, and more preferably 0.1 to 1 μm. If the thickness of the charge generation layer 26 is less than 0.05 μm, there is a tendency that sufficient sensitivity is not exhibited. On the other hand, when the film thickness of the charge generation layer 26 exceeds 5 μm, there is a tendency to cause adverse effects such as poor charging properties.

  The charge transport layer 27 includes a charge transport material and a binder resin. A well-known thing can be used as a charge transport material, The following can be illustrated. Oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1- [pyridyl- (2)]-3 Pyrazoline derivatives such as-(p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, triphenylamine, tri (p-methyl) phenylamine, N, N'-bis (3,4-dimethylphenyl) biphenyl Aromatic tertiary amino compounds such as -4-amine, dibenzylaniline, 9,9-dimethyl-N, N′-di (p-tolyl) fluoren-2-amine, N, N′-diphenyl-N, Aromatic tertiary diamino compounds such as N′-bis (3-methylphenyl)-[1,1-biphenyl] -4,4′-diamine, 3- (4′-dimethylaminophenyl) Nyl) -5,6-di- (4′-methoxyphenyl) -1,2,4-triazine, 1,2,4-triazine derivatives, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, 4-diphenyl Hydrazone derivatives such as aminobenzaldehyde-1,1-diphenylhydrazone, [p- (diethylamino) phenyl] (1-naphthyl) phenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, 6-hydroxy-2, Benzofuran derivatives such as 3-di (p-methoxyphenyl) -benzofuran, α-stilbene derivatives such as p- (2,2-diphenylvinyl) -N, N′-diphenylaniline, enamine derivatives, N-ethylcarbazole, etc. Carbazole derivatives, poly-N-vinylcarbazole and derivatives thereof Hole transport material such as body.

  Quinone compounds such as chloranil, bromoanil, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2- ( 4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4-oxadiazole, 2,5 -Oxadiazole compounds such as bis (4-diethylaminophenyl) 1,3,4 oxadiazole, xanthone compounds, thiophene compounds, 3,3 ', 5,5'-tetra-t-butyldiphenoquinone, etc. Electron transport materials such as diphenoquinone compounds. Or the polymer etc. which have the group which consists of a compound shown above in the principal chain or a side chain are mentioned. These charge transport materials can be used alone or in combination of two or more.

  As the binder resin, a known resin can be used, and among them, a resin capable of forming an electrically insulating film is preferable. For example, polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, acrylonitrile-styrene copolymer Polymer, acrylonitrile-butadiene 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-carbazole, polyvinyl butyral, polyvinyl formal, polysulfone, casein, gelatin, polyvinyl alcohol, ethyl cellulose, phenol resin, polyamide Cal Bokishi methylcellulose, vinylidene polymer wax chloride, polyurethane, polyarylate, polyacrylamide, chlorinated rubber, polyvinyl carbazole, polyvinyl anthracene, although polyvinyl pyrene, and the like, but is not limited thereto.

  These binder resins are used singly or in combination of two or more. Of these, polycarbonate resins, polyester resins, methacrylic resins, and acrylic resins are particularly preferred because of their excellent compatibility with charge transport materials, solubility in solvents, and strength. The blending ratio (weight ratio) between the binder resin and the charge transport material can be arbitrarily set in any case, but attention must be paid to a decrease in electrical characteristics and a decrease in film strength.

  In addition, when the charge transport layer 27 is a surface layer of an electrophotographic photosensitive member (a layer disposed on the side farthest from the conductive substrate of the photosensitive layer), the charge transport layer 27 imparts lubricity to the surface layer. Lubricant particles (for example, silica particles, alumina particles, polytetrafluoroethylene (PTFE), etc.) in order to make them less likely to be worn or scratched, and to improve the cleaning performance of the developer attached to the photoreceptor surface. Of fluorine resin particles and silicone resin fine particles). These lubricating particles can be used in combination of two or more. In particular, fluorine resin particles are preferably used. Fluorine-based resin particles are made of tetrafluoroethylene resin, trifluorinated ethylene resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodiethylene chloride resin and their co-polymers. Coalescence is mentioned. These can be used alone or in combination of two or more. Among the above, tetrafluoroethylene resin and vinylidene fluoride resin are preferable.

  The primary particle size of the fluororesin particles is preferably 0.05 to 1 μm, more preferably 0.1 to 0.5 μm. If the primary particle size is less than 0.05 μm, aggregation during dispersion tends to proceed easily. On the other hand, if it exceeds 1 μm, image quality defects tend to occur.

  The content of the fluororesin particles in the charge transport layer 27 is preferably 0.1 to 40 wt%, more preferably 1 to 30 wt% with respect to the total solid content of the charge transport layer 27. If the content is less than 0.1 wt%, the modification effect due to the dispersion of the fluorine-based resin particles tends to be insufficient. On the other hand, if it exceeds 40 wt%, the light transmission property tends to decrease and the residual potential tends to increase due to repeated use.

  The charge transport layer 27 can be formed by applying and drying a charge transport layer forming coating solution in which a charge transport material, a binder resin, and other materials are dissolved in a suitable solvent.

  Examples of the solvent used for forming the charge transport layer 27 include aromatic hydrocarbon solvents such as toluene and chlorobenzene, aliphatic alcohol solvents such as methanol, ethanol, and n-butanol, acetone, cyclohexanone, and 2-butanone. Such as ketone solvents, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform and ethylene chloride, cyclic or linear ether solvents such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether, or mixed solvents thereof. Can be used. The mixing ratio of the charge transport material and the binder resin is preferably 10: 1 to 1: 5.

  A small amount of silicone oil can be added to the coating solution for forming the charge transport layer as a leveling agent for improving the smoothness of the coating film.

  As a method for dispersing the fluorine-based resin in the charge transport layer 27, a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a high-pressure homogenizer, an ultrasonic disperser, a colloid mill, a collision-type medialess disperser, a through-type medialess A method such as a disperser can be used.

  Examples of the dispersion of the coating liquid for forming the charge transport layer 27 include a method of dispersing the fluororesin particles in a solution of a binder resin, a charge transport material and the like dissolved in a solvent.

  Moreover, in the coating liquid manufacturing process, it is preferable to control the temperature of the coating liquid to 0 ° C to 50 ° C. Methods for controlling the temperature of the coating liquid include: cooling with water, cooling with wind, cooling with refrigerant, adjusting the room temperature of the manufacturing process, warming with hot water, warming with hot air, warming with a heater, heating A method of making a coating liquid manufacturing facility with a material that is difficult to heat, a method of making a coating liquid manufacturing facility with a material that easily dissipates heat, a method of making a coating liquid manufacturing facility with a material that easily stores heat, and the like can be used.

  As a method for mixing the coating solution, a method using a stirrer, stirring with a stirring blade, a roll mill, a sand mill, an attritor, a ball mill, a high-pressure homogenizer, an ultrasonic disperser, or the like can be used. As a dispersion method, a method using a sand mill, an attritor, a ball mill, a high-pressure homogenizer, an ultrasonic disperser, a roll mill, or the like can be used.

  In order to improve the dispersion stability of the dispersion and to prevent aggregation during the formation of the coating film, it is also effective to add a small amount of a dispersion aid to the dispersion station. Examples of the dispersion aid include a fluorine-based surfactant, a fluorine-based polymer, a silicone-based polymer, and a silicone oil.

  Coating methods used when the charge transport layer 27 is provided include push-up coating method, roll coater coating method, gravure coater coating method, blade coating method, wire bar coating method, spray coating method, dip coating method, bead coating method, air Usual methods such as a knife coating method and a curtain coating method can be used.

  The thickness of the charge transport layer 27 is preferably 5 to 50 μm, and more preferably 10 to 40 μm.

  Further, for the purpose of preventing deterioration of the photoreceptor due to ozone, oxidizing gas or light / heat generated in the image forming apparatus, an anti-oxidant, a light stabilizer, etc. are added to the electrophotographic photoreceptor. An agent can be added.

  Antioxidants include hindered phenols, hindered amines, paraphenylenediamines, arylalkanes, hydroquinones, spirochromans, spiroidanones and their derivatives, organic sulfur compounds, and organic phosphorus compounds.

  Examples of phenolic antioxidants include 2,6-di-t-butyl-4-methylphenol, styrenated phenol, n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxy Phenyl) -propionate, 2,2′-methylene-bis (4-methyl-6-tert-butylphenol), 2-tert-butyl-6- (3′-tert-butyl-5′-methyl-2′-hydroxy) Benzyl) -4-methylphenyl acrylate, 4,4′-butylidene-bis- (3-methyl-6-tert-butyl-phenol), 4,4′-thio-bis- (3-methyl-6-t-) Butylphenol), 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl) − '-Hydroxy-phenyl) propionate] -methane, 3,9-bis [2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl]- Examples include 2,4,8,10-tetraoxaspiro [5,5] undecane.

  Examples of hindered amine compounds include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy]- 2,2,6,6-tetramethylpiperidine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine succinate Polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diimyl} {(2,2,6,6-tetra Methyl-4-piperidyl) imino} hexamethylene {(2,3,6,6-tetramethyl-4-piperidyl) imino}], 2- (3,5-di-t-butyl-4-hydroxybenzyl)- 2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl- N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate and the like.

  Examples of organic sulfur antioxidants include dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, pentaerythritol-tetrakis. -(Β-lauryl-thiopropionate), ditridecyl-3,3′-thiodipropionate, 2-mercaptobenzimidazole and the like.

  Examples of the organophosphorus antioxidant include trisnonylphenyl phosfte, triphenyl phosfte, tris (2,4-di-t-butylphenyl) -phosfte, and the like.

  The organic sulfur-based and organic phosphorus-based antioxidants are called secondary antioxidants, and a synergistic effect can be obtained by using them together with primary antioxidants such as phenol-based or amine-based antioxidants.

  Examples of the light stabilizer include benzophenone-based, benzotriazole-based, dithiocarbamate-based, and tetramethylpiperidine-based derivatives.

  Examples of the benzophenone light stabilizer include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-di-hydroxy-4-methoxybenzophenone, and the like. Examples of the benzotriazole-based light stabilizer include 2- (2′-hydroxy-5′-methylphenyl) -benzotriazole, 2- [2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ′). ', 6' '-tetra-hydrophthalimido-methyl) -5'-methylphenyl] -benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzo Triazole, 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-t-butylphenyl)- Benzotriazole, 2- (2′-hydroxy-5′-t-octylphenyl) -benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-amylphenyl) -benzo Riazor, and the like. Examples of other compounds include 2,4-di-t-butylphenyl-3 ', 5'-di-t-butyl-4'-hydroxybenzoate and nickel dibutyl-dithiocarbamate.

  In addition, at least one electron accepting substance can be contained for the purpose of improving sensitivity, reducing residual potential, reducing fatigue during repeated use, and the like.

Examples of the electron accepting substance include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene. , Chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, phthalic acid and the like. Of these, fluorenone-based, quinone-based, and benzene derivatives having an electron-withdrawing substituent such as Cl, CN, NO ₂ are particularly preferable.

  In the electrophotographic photoreceptor 1 having a laminated structure, the protective layer 25 is provided to prevent chemical change of the charge transport layer 27 during charging and to further improve the mechanical strength of the photosensitive layer 24.

  The protective layer 25 includes a binder resin (including a curable resin) and a charge transporting compound. Examples of the form of the protective layer 25 include a cured resin film including a curable resin and a charge transporting compound, and a film formed by including a conductive material in an appropriate binder resin. Any known resin can be used as the curable resin, and examples thereof include phenol resin, polyurethane resin, melamine resin, diallyl phthalate resin, and siloxane resin.

As the protective layer 25 formed including a charge transporting compound, a cured film formed including a compound represented by the following general formula (I-1) is preferable.
_{^{F 1 [-D 1 -Si (OR}} 2) a (R 1) 3-a] b ··· (I-1)
[In Formula (I-1), F ¹ represents an organic group derived from a charge transporting compound, D ¹ represents a divalent group (flexible subunit), R ¹ represents a hydrogen atom, an alkyl group And R 1 represents one selected from the group consisting of a substituted or unsubstituted aryl group, R ² represents one selected from the group consisting of hydrogen, an alkyl group, and a trialkylsilyl group; The integer of 3 is represented, b represents the integer of 1-4. ]

Note that the charge transporting compound represented by F ¹ is a photofunctional compound (compound having a photocarrier transporting ability consisting of holes or electrons).

In the general formula (I-1), the organic group represented by F ¹ is not particularly limited as long as it has a photocarrier transport ability composed of holes or electrons, and has a conventional charge transport material. What is necessary is just to have the structure as it is. Specifically, a skeleton of a compound having a hole transporting property such as a triarylamine compound, a benzidine compound, an arylalkane compound, an aryl-substituted ethylene compound, a stilbene compound, an anthracene compound, or a hydrazone compound, and A compound having a skeleton of a compound having an electron transporting property such as a quinone compound, a fluorenone compound, a xanthone compound, a benzophenone compound, a cyanovinyl compound, or an ethylene compound can be used.

In general formula (I-1), the moiety represented by —Si (OR ² ) _a (R ¹ ) _3-a functions as a characteristic group having a hydrolyzable group (hereinafter referred to as “substituted silicon group”). To do. This substituted silicon group, when there is another adjacent substituted silicon group, causes a crosslinking reaction with each other at the portion of the -Si- group, and -Si-O-Si in which an oxygen atom is bridged between the adjacent -Si- groups. -Bonds are formed in a three-dimensional manner. That is, this substituted silicon group plays a role of forming a so-called inorganic glassy network in the protective layer 25.

In the general formula (I-1), D ¹ specifically links the portion of F ¹ for imparting photoelectric characteristics to a substituted silicon group that contributes to the construction of a three-dimensional inorganic glassy network. It is a divalent group that plays a role. Further, D ¹ represents an organic base structure that imparts moderate flexibility to the portion of the inorganic glassy network that is hard but brittle, and plays a role of improving mechanical toughness as a film (protective layer 25). .

Specifically, as D ¹ , a divalent hydrocarbon group represented by —C ₁ H _2l —, —C _m H _2m-2 —, or —C _n H _2n-4 — (where l is 1 to 15 M represents an integer of 2 to 15, n represents an integer of 3 to 15), —COO—, —S—, —O—, —CH ₂ —C ₆ H ₄ —, —N ═CH—, — (C ₆ H ₄ ) — (C ₆ H ₄ ) —, and a characteristic group having a structure in which these characteristic groups are arbitrarily combined, and further, the constituent atoms of these characteristic groups are substituted with other atoms. And those substituted with a group.

  In general formula (I-1), b is preferably 2 or more. When b is 2 or more, the charge transport material represented by the general formula (I-1) contains two or more Si atoms, so that an inorganic glassy network is easily formed, and mechanical strength is improved. To do.

  As a compound represented by general formula (I-1), the compound represented by the following general formula (I-2) is preferable. The compound represented by the following general formula (I-2) is a compound having a hole transporting ability (hole transporting material), and the inclusion of the compound in the protective layer 25 particularly affects the electrical characteristics and mechanical properties of the protective layer 25. It is preferable from the viewpoint of improving strength characteristics.

In general formula (I-2), Ar ¹ , Ar ² , Ar ³ and Ar ⁴ may be the same or different and each represents a substituted or unsubstituted aryl group, and Ar ⁵ represents a substituted or unsubstituted aryl group. Or, it represents an arylene group, k represents 0 or 1, and 1 to 4 characteristic groups of Ar ^{1 to} Ar ⁵ have a structure represented by the following general formula (I-3).

—Y ¹ —Si (OR ² ) _a R ¹ _3-a (I-3)
In the general formula (I-3), a, ^{R 1} and ^{R 2} are a in each formula (I-1) in a ^{R 1} and ^{R 2} synonymous, ^{Y 1} represents a divalent group.

Here, as Y ¹ , specifically, a divalent hydrocarbon group represented by —C ₁ H _2l —, —C _m H _2m-2 —, or —C _n H _2n-4 — (where l is 1 represents an integer of 1 to 15, m represents an integer of 2 to 15, and n represents an integer of 3 to 15), a substituted or unsubstituted divalent aryl group, —N═CH—, —O—, And one divalent group selected from the group consisting of -COO-. Y ¹ may be a characteristic group having a structure in which divalent groups selected from the above groups are arbitrarily combined.

Ar ^{1 to} Ar ⁵ in the general formula (I-2) are preferably any of the following formulas (I-4) to (I-10).

Here, in formulas (I-4) to (I-10), R ⁶ , R ⁷ and R ⁸ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkyl having 1 to 4 carbon atoms. 1 type chosen from the group which consists of a phenyl group substituted by a group or a C1-C4 alkoxy group, an unsubstituted phenyl group, and a C7-C10 aralkyl group. R ⁹ represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom. X represents a characteristic group having a structure represented by the general formula (I-3), m and s each represents 0 or 1, and t represents an integer of 1 to 3.

  Here, as Ar in Formula (I-10), what is represented by following formula (I-11) or (I-12) is preferable.

In formulas (I-11) and (I-12), R ¹⁰ and R ¹¹ have the same meanings as R ⁹ described above. T represents an integer of 1 to 3.

  In addition, as Z ′ in the formula (I-10), t of 0 is preferable among those represented by the following formulas (I-11) and (I-12).

Moreover, as described above, in formulas (I-4) to (I-10), X represents a characteristic group having a structure represented by general formula (I-3). Y ¹ in the characteristic group is a divalent hydrocarbon group represented by —C ₁ H _2l —, —C _m H _2m-2 —, or —C _n H _2n-4 — described above (here, , L represents an integer of 1 to 15, m represents an integer of 2 to 15, and n represents an integer of 3 to 15), -N = CH-, -O-, -COO-,- S-,-(CH) _β- (β represents an integer of 1 to 10), the general formula (I-11) described above, the general formula (I-12) described above, the following general formula (I -13) and the characteristic group represented by (I-14).

Here, in formula (I-14), y and z each represent an integer of 1 to 5, t represents an integer of 1 to 3, and as described above, R ⁹ represents a hydrogen atom, a carbon number of 1 to 1 type chosen from the group which consists of a 4 alkyl group, a C1-C4 alkoxy group, and a halogen atom.

As described above, Ar ⁵ in formula (I-2) represents a substituted or unsubstituted aryl group or arylene group. When k = 0, formula (I-15) shown in Table 4 To (I-19) is preferable, and moreover, when k = 1, it is more preferable to apply to any of formulas (I-20) to (I-24) shown in Table 5.

Ar ⁵ in formula (I-2) is any one of formulas (I-15) to (I-19) shown in Table 4, and further formulas (I-20) to (I-20) shown in Table 5. In the case of taking any structure of −24), Z ′ in the formulas (I-19) and (I-24) is selected from the group consisting of the following general formulas (I-25) to (I-32) It is preferable that it is 1 type selected.
_{- (CH 2) q - (} I-25)
_{- (CH 2 CH 2 O)} r - (I-26)

Here, in formulas (I-31) to (I-32), R ¹² and R ¹³ are each a group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom. 1 represents a divalent group, q and r each represent an integer of 1 to 10, and t represents an integer of 1 to 2, respectively.

  W in the formulas (I-31) and (I-32) is preferably any one of divalent groups represented by the following (I-31) to (I-41). In formula (I-40), u represents an integer of 0 to 3.

—CH ₂ — (I-33)
_{-C (CH 3) 2 - ···} (I-34)
-O- (I-35)
-S- (I-36)
-C (CF ₃ ) _2- (I-37)
—Si (CH ₃ ) ₂ — (I-38)

  Moreover, as a specific example of a compound represented by general formula (I-2), the thing of the compound numbers 1-274 of Table 1-Table 55 in Unexamined-Japanese-Patent No. 2001-83728 can be used, for example.

  Furthermore, the charge transport material represented by the general formula (I-1) may be used alone or in combination of two or more. In addition to the charge transport material represented by the general formula (I-1), a compound represented by the following general formula (II) may be used in combination for the purpose of further improving the mechanical strength of the cured film.

B {-Si (OR < ² >) _a (R < ¹ >) _3-a } [ _gamma] (II)
Here, a in formula (II), ^{R 1} and ^{R 2} each destination mentioned formula (I-1) in a, has the same meaning as ^{R 1} and ^{R 2,} B is a divalent organic group Γ represents an integer of 2 or more.

  The compound represented by the general formula (II) is a compound having a substituted silicon group having a hydrolyzable group described above. In the compound represented by the general formula (II), the moiety of the —Si— group contained in the substituted silicon group is a charge transport material represented by the general formula (I-1) or other adjacent general formula. It reacts with the substituted silicon group of the compound represented by (II) to form a three-dimensional bond of —Si—O—Si— in which oxygen atoms are bridged between adjacent —Si— groups. That is, a so-called inorganic glass is formed in the protective layer 25 by a hydrolysis reaction that proceeds between substituted silicon groups of the compound represented by the general formula (II) and the charge transport material represented by the general formula (I-1). A quality network is formed.

The charge transport material represented by the general formula (I-1) can also form the protective layer 25 (cured film) having an inorganic glassy network by itself as described above. Since the compound represented by (II) has two or more alkoxysilyl groups, it is considered that the crosslinked structure of the cured film is easily formed three-dimensionally and has higher mechanical strength. In addition, the compound represented by the general formula (II) is suitable for the cured film, like the D ¹ portion in the charge transport material represented by the general formula (I-1), by being a constituent material of the cured film. There is also a role to give flexibility.

As the compound represented by the general formula (II), those represented by the following general formulas (II-1) to (II-5) are preferable. In formulas (II-1) to (II-5), T ¹ and T ² each represent a divalent or trivalent hydrocarbon group that may be independently branched. A represents the substituted silicon group having hydrolyzability described above. h, i, and j each independently represent an integer of 1 to 3. The compounds represented by formulas (II-1) to (II-5) are selected so that the number of A in the molecule is 2 or more.

  Table 9 shows compounds (formulas (III-1) to (III-19)) which are preferable examples of the compound represented by the general formula (II). In Table 9, Me represents a methyl group, Et represents an ethyl group, and Pr represents a propyl group.

  In addition to the compound represented by the general formula (I), another compound capable of crosslinking reaction may be used in combination. As such a compound, various silane coupling agents and commercially available silicon-based hard coat agents can be used.

  As silane coupling agents, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxy Silane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltriethoxysilane, tetramethoxysilane, methyltrimethoxy Examples thereof include silane and dimethyldimethoxysilane.

  As a commercially available hard coat agent, KP-85, CR-39, X-12-2208, X-40-9740, X-41-1007, KNS-5300, X-40-2239 (above, manufactured by Shin-Etsu Silicone Co., Ltd.) ), AY42-440, AY42-441, AY49-208 (manufactured by Toray Dow Corning).

  A fluorine atom-containing compound can be added to the protective layer 25 for the purpose of imparting surface lubricity. By improving the surface lubricity, the friction coefficient between the electrophotographic photosensitive member 1 and the cleaning member is lowered, and the wear resistance can be improved. In addition, it has an effect of preventing adhesion of discharge products, developer, paper dust, and the like to the surface of the photoreceptor, which is useful for improving the life of the photoreceptor.

  Examples of the fluorine atom-containing compound include fluorine atom-containing polymers such as polytetrafluoroethylene. They can be added as they are or in the form of fine particles of fluorine atom-containing polymer.

  In the case where the protective layer 25 is a cured film formed of the compound represented by the general formula (I), a fluorine atom-containing compound that can react with alkoxysilane is added to constitute a part of the crosslinked film. It is desirable.

  Specific examples of the fluorine atom-containing compound include (tridecafluoro-1,1,2,2-tetrahydrooctyl) triethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, and 3- (heptafluoro). Isopropoxy) propyltriethoxysilane, 1H, 1H, 2H, 2H-perfluoroalkyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorooctyltri An ethoxysilane etc. are mentioned.

  The addition amount of the fluorine atom-containing compound is preferably 20% by weight or less. Beyond this, a problem may occur in the film formability of the crosslinked cured film.

  The protective layer 25 has sufficient oxidation resistance, but an antioxidant may be added for the purpose of imparting stronger oxidation resistance.

  Antioxidants are preferably hindered phenols or hindered amines, organic sulfur antioxidants, phosphite antioxidants, dithiocarbamate antioxidants, thiourea antioxidants, benzimidazole antioxidants. You may use well-known antioxidants, such as. The addition amount of the antioxidant is preferably 15% by weight or less, and more preferably 10% by weight 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.

  It is also possible to add known additives used for forming a coating film to the protective layer 25, and known materials such as leveling agents, ultraviolet absorbers, light stabilizers, and surfactants can be used.

  The protective layer 25 preferably contains the lubricating particles described in the charge transport layer 27. By containing such particles, the lubricity of the protective layer 25 is improved, it is difficult to be worn and scratched, and the cleaning property of the developer adhering to the surface of the photoreceptor is improved. Among such lubricating particles, the fluorine resin particles described in the charge transport layer 27 are preferable.

  In order to form the protective layer 25, a protective layer-forming coating solution containing a mixture of the aforementioned various materials and various additives is prepared, applied onto the photosensitive layer 24, and heat-treated. Thereby, a cross-linking curing reaction is caused three-dimensionally to form a strong cured film. The temperature of the heat treatment is not particularly limited as long as it does not affect the underlying photosensitive layer 24, but is preferably from room temperature to 200 degrees, particularly preferably from 100 to 160 degrees.

  In the formation of the protective layer 25, the crosslinking curing reaction may be performed without a catalyst, but an appropriate catalyst may be used. Catalysts include acid catalysts such as hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid and trifluoroacetic acid, bases such as ammonia and triethylamine, organotin compounds such as dibutyltin diacetate, dibutyltin dioctoate and stannous oxalate, tetra -Organic titanium compounds such as -n-butyl titanate and tetraisopropyl titanate, iron salts, manganese salts, cobalt salts, zinc salts, zirconium salts and aluminum chelate compounds of organic carboxylic acids.

  In order to make application | coating easy for the coating liquid for protective layer formation, a solvent can be added and used as needed. Specifically, water, methanol, ethanol, n-propanol, i-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, Examples include ordinary solvents such as methylene chloride, chloroform, dimethyl ether, and dibutyl ether. These can be used individually by 1 type or in mixture of 2 or more types.

  In the formation of the protective layer 25, as a coating method, a normal 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 may be used. it can.

  The thickness of the protective layer 25 is preferably 0.5 to 20 μm, and particularly preferably 2 to 10 μm.

  In the electrophotographic photosensitive member 1, in order to obtain high resolution, the thickness of the functional layer above the charge generation layer 26 is preferably adjusted to 50 μm or less, more preferably 40 μm or less. When the functional layer is a thin film, a combination of a particle-dispersed undercoat layer and a high-strength protective layer is particularly effectively used.

  The electrophotographic photoreceptor 1 is not limited to the above configuration. For example, the electrophotographic photoreceptor 1 may have a configuration in which the intermediate layer 23 and / or the protective layer 25 are not present. That is, a configuration in which the undercoat layer 22 and the photosensitive layer 24 are formed on the conductive substrate 21, and a configuration in which the undercoat layer 22, the intermediate layer 23, and the photosensitive layer 24 are sequentially formed on the conductive substrate 21. Alternatively, an undercoat layer 22, a photosensitive layer 24, and a protective layer 25 may be sequentially formed on the conductive substrate 21.

  The charge generation layer 26 and the charge transport layer 27 may be stacked in reverse order. Further, the photosensitive layer 24 may have a single layer structure. In that case, a protective layer may be provided on the photosensitive layer, or both an undercoat layer and a protective layer may be provided. Further, an intermediate layer may be provided on the undercoat layer as described above.

The electrophotographic photosensitive member 1 can be used in an image forming apparatus such as a laser beam printer, a digital copying machine, an LED printer, or a laser facsimile that emits near-infrared light or visible light. The laser beam is preferably a laser that oscillates light of 350 to 800 nm in order to obtain a high-definition image. Furthermore, the laser beam preferably has a spot diameter of 10 ⁴ μm ² or less, and more preferably 3 × 10 ³ μm ² or less, in order to obtain a high-definition image.

  Next, the developer will be described in detail. The developer may be a one-component developer or a two-component developer.

  The developer includes toner (hereinafter, sometimes referred to as “toner particles”). The toner particles may be, for example, a kneading and pulverizing method in which a binder resin, a colorant, a release agent, and a charge control agent, if necessary, are kneaded, pulverized, and classified; the particles obtained by the kneading and pulverizing method are mechanically impacted. A method of changing the shape by force or thermal energy; emulsion polymerization of a polymerizable monomer of a binder resin, and dispersion of the obtained dispersion, a colorant, a release agent, and, if necessary, a charge control agent The emulsion polymerization aggregation method to obtain toner particles by mixing and agglomerating and heat-fusing the solution; a solution of a binder resin polymerizable monomer and a colorant, a release agent, and a charge control agent as necessary Suspension polymerization method in which the polymer is suspended in an aqueous solvent; a suspension method in which a binder resin, a colorant, a release agent, and a charge control agent, if necessary, are suspended in an aqueous solvent and granulated Toner particles produced by the above method.

  Among them, from the viewpoint of shape control and particle size distribution control, toner particles obtained by a suspension polymerization method, an emulsion polymerization aggregation method, and a dissolution suspension method manufactured with an aqueous solvent are preferable, such as a suspension polymerization method and an emulsion polymerization aggregation method. Toner particles obtained by a polymerization method are more preferred, and toner particles obtained by an emulsion polymerization aggregation method are particularly preferred.

The toner particles obtained by the above polymerization method usually have a volume average particle diameter of 2 to 12 μm, but preferably 3 to 9 μm. When the volume average particle diameter is less than 2 μm, the amount of toner remaining on the surface of the photoreceptor without being cleaned tends to increase, which tends to cause image staining. On the other hand, if it exceeds 12 μm, it tends to be difficult to obtain a fine high-quality image. Further, by using toner particles having an average shape factor (ML ² / A) of 115 to 145, an image with high development, transferability, and high image quality can be obtained.

  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 have a core-shell structure can be used.

  The toner particles may be composed of toner base particles alone including a binder resin, a colorant, a release agent, and the like, and may include external additives in addition to the toner base particles. When an external additive is included, the toner particles can be produced by mixing the toner base particles and the external additive with a Henschel mixer or a V blender. Further, when the toner particles are produced by a wet method, an external additive can be added by a wet method.

  Binder resins include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate, and methyl acrylate. , Α-methylene aliphatic monocarboxylic esters such as ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, vinyl Examples thereof include homopolymers and copolymers of vinyl ethers such as methyl ether, vinyl ethyl ether, and vinyl butyl ether, and vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone. Typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. Examples thereof include coalescence, polyethylene, and polypropylene. Further examples include polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like.

  Coloring agents include 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, and 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 can be exemplified as a representative one.

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

  In addition, a charge control agent may be added to the toner particles as necessary. Known charge control agents can be used, but azo metal complex compounds, metal complex compounds of salicylic acid, and resin type charge control agents containing polar groups can be used. When the toner is manufactured by a wet manufacturing method, it is preferable to use a material that is difficult to dissolve in water in terms of controlling ionic strength and reducing wastewater contamination. The toner particles may be either a magnetic toner containing a magnetic material or a non-magnetic toner containing no magnetic material.

  Abrasive fine particles may be added to the toner particles for the purpose of removing deposits and deteriorated substances on the surface of the electrophotographic photoreceptor 1. Examples of the abrasive fine particles include inorganic fine particles, organic fine particles, and composite fine particles obtained by attaching inorganic fine particles to the organic fine particles. Inorganic fine particles having excellent abrasive properties are particularly preferable.

  Inorganic fine 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, aluminum oxide, barium sulfate, silicon carbide, boron carbide, titanium carbide, silicon nitride, titanium nitride, and boron nitride, nitrides, borides, and the like are preferably used.

  The inorganic fine particles include titanium coupling agents such as tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, γ- (2-amino Ethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxysilane Hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane Treatment may be performed with a silane coupling agent such as decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, or p-methylphenyltrimethoxysilane.

  Moreover, you may hydrophobize with higher fatty acid metal salts, such as silicone oil, aluminum stearate, a zinc stearate, a calcium stearate.

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

  The average particle size of the organic fine particles is preferably 5 nm to 1000 nm, more preferably 5 nm to 800 nm, and even more preferably 5 nm to 700 nm. If the average particle size is too small, the polishing ability is insufficient, the discharge product removability is lowered, and there is a tendency that an image flow is caused by moisture absorption of the discharge product. On the other hand, if it is too large, the surface of the electrophotographic photoreceptor 1 tends to be easily damaged.

  The amount of abrasive fine particles added to the toner particles is preferably 0.01 to 2.0% by weight, more preferably 0.05 to 1.0% by weight. When the addition amount is too small, the polishing ability is insufficient, the discharge product removability is lowered, and there is a tendency that an image flow due to moisture absorption of the discharge product occurs. On the other hand, if the amount is too large, the surface of the electrophotographic photosensitive member tends to be damaged.

  A lubricity imparting agent may be added to the toner particles for the purpose of further reducing the torque or preventing the toner from fusing by increasing the pressing force of the toner.

  Lubricating agents 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 acid Aliphatic amides such as amides, erucic acid amides, ricinoleic acid amides, stearic acid amides, plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil, and beeswax Minerals such as animal waxes, montan waxes, ozokerites, ceresins, paraffin waxes, microcrystalline waxes, Fischer-Tropsch waxes, etc., petroleum waxes, and modified products thereof can be used. These can be used alone or in combination of two or more.

  However, the average particle size may be in the range of 0.1 to 10 μm, and the particles having the above chemical structure may be pulverized to have the same particle size. The amount added to the toner is preferably in the range of 0.01 to 2.0% by weight, more preferably 0.05 to 1.5% by weight.

  As the other inorganic oxide added to the toner particles, it is preferable to use a small-diameter inorganic oxide having a primary particle size of 40 nm or less for powder flowability, charge control and the like. Further, it is preferable to add an inorganic oxide having a larger diameter than that in order to reduce adhesion and control charging. These inorganic oxide fine particles may be known ones, but it is preferable to use silica and titanium oxide in combination for precise charge control. Further, the surface treatment of the small-diameter inorganic fine particles increases the dispersibility and increases the effect of increasing the powder fluidity.

  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 coating are used. The mixing ratio with the carrier can be set as appropriate.

  The wear amount and surface roughness of the electrophotographic photosensitive member are preferably controlled appropriately. As this means, adjustment of the contact condition of the cleaning blade member to the photosensitive member, optimization of the blade surface layer material, control by the material of the blade member, adjustment by combined use with a polishing roll and a brush member, surface layer of the electrophotographic photosensitive member There are methods such as strength control by materials and control by adding abrasive fine particles and a lubricity-imparting agent to the toner. By combining these controls, it is controlled within an appropriate range.

Next, the cleaning device 11 will be described in detail.
The cleaning device preferably includes a cleaning member that contacts the electrophotographic photosensitive member 1 with a linear pressure of 10 to 150 g / cm (preferably 15 to 100 g / cm). When the linear pressure of the cleaning member is less than 10 g / cm, a phenomenon that the developer slips through the cleaning blade tends to occur. Therefore, the surface of the electrophotographic photosensitive member is easily worn by the developer remaining on the surface of the electrophotographic photosensitive member in the charging process of the next cycle.

  On the other hand, when the linear pressure of the cleaning member exceeds 150 g / cm, filming due to the developer remaining on the surface of the electrophotographic photosensitive member, damage to the surface of the electrophotographic photosensitive member, and excessive wear tend to occur. Therefore, the wear makes it easy for foreign matter that has pierced the photoreceptor to reach the conductive substrate, and leaks easily occur.

  An example of the cleaning member is a cleaning blade. As a material for the cleaning blade, urethane rubber, silicon rubber, fluorine rubber, chloroprene rubber, butadiene rubber, or the like can be used. Among them, it is preferable to use a polyurethane elastic body because of its excellent wear resistance.

  As the polyurethane elastic body, a polyurethane synthesized through an addition reaction of an isocyanate, a polyol and various hydrogen-containing compounds is generally used. As the polyol component, polyether polyols such as polypropylene glycol and polytetramethylene glycol, and polyester polyols such as adipate polyol, polycaprolactam polyol, and polycarbonate polyol are used. Examples of the polyisocyanate component include tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, toluidine diisocyanate and other aromatic polyisocyanates, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, dicyclohexylmethane diisocyanate, and the like. The following aliphatic polyisocyanates are used. It is manufactured by preparing a urethane prepolymer using the polyol component and the polyisocyanate component, adding a curing agent to the urethane prepolymer, pouring it into a predetermined mold, crosslinking and curing, and then aging at room temperature.

  As the curing agent, a dihydric alcohol such as 1,4-butanediol and a trihydric or higher polyhydric alcohol such as trimethylolpropane or pentaerythritol are usually used in combination.

The physical properties of the cleaning blade include, for example, hardness (JISA scale) 50 to 90, Young's modulus 40 to 90 (kg / cm ² ), 100% modulus 20 to 65 (kg / cm ² ), 300% modulus 70 to 150 ( kg / cm ² ), tensile strength 240-500 (kg / cm ² ), elongation 290-500 (%), rebound resilience 30-70 (%), tear strength 25-75 (kg / cm ² ), permanent Those having an elongation of 4.0% or less can be used. Further, the contact setting angle of the blade is preferably 10 to 40 (°).

  Hereinafter, an image forming method of the present invention using the above-described image forming apparatus 100 will be described.

  First, in the image forming apparatus 100, when the electrophotographic photosensitive member 1 is driven to rotate, the charging device 3 is driven in conjunction with the rotation. Then, the surface of the electrophotographic photosensitive member 1 is uniformly charged to a predetermined polarity and potential (charging process). Next, the electrophotographic photosensitive member 1 whose surface is uniformly charged is exposed imagewise by the laser light emitted from the exposure device 5, and an electrostatic latent image is formed on the surface of the photosensitive member 1 (exposure step). ).

  The electrostatic latent image is developed with toner of the developing device 7 to form a toner image (development process). The toner at this time may be a two-component toner or a one-component toner.

  This toner image is transferred to a transfer medium in the process of passing through the interface between the photoreceptor 1 and the transfer device 9 (transfer process). Further, the toner remaining on the photoreceptor 1 is removed by the cleaning device 11 (cleaning step).

  FIG. 3 is a schematic view showing another preferred embodiment of the image forming apparatus of the present invention. The image forming apparatus shown in FIG. 3 has the same configuration as that of the image forming apparatus 100 shown in FIG. 3 except that it includes a charging device 4 that charges the electrophotographic photoreceptor 1 by a contact method. In particular, in the image forming apparatus 110 that employs a contact-type charging device in which an AC voltage is superimposed on a DC voltage, the electrophotographic photoreceptor 1 can be preferably used because it has excellent wear resistance. In this case, the static eliminator 14 may not be provided.

  In the contact charging method, charging members such as a roller shape, a blade shape, a belt shape, a brush shape, and a magnetic brush shape are applicable. In particular, the roller-shaped or blade-shaped charging member may be arranged in a contact state or a non-contact state having a certain amount of gaps (100 μm or less) with respect to the photoreceptor.

A roller-shaped charging member, a blade-shaped charging member, and a belt-shaped charging member are composed of a material adjusted to an electric resistance (10 ³ Ω to 10 ⁸ Ω) effective as a charging member, You may be comprised from several layers.

  The material is mainly composed of synthetic rubber such as urethane rubber, silicon rubber, fluorine rubber, chloroprene rubber, butadiene rubber, EPDM, epichlorohydrin rubber, and elastomers such as polyolefin, polystyrene, vinyl chloride, conductive carbon, metal oxide. In addition, an appropriate electrical conductivity imparting agent such as an ionic conductive agent may be blended in an appropriate amount to develop an effective electrical resistance as a charging member.

  Furthermore, a resin such as nylon, polyester, polystyrene, polyurethane, silicone, etc. is made into a paint, and an appropriate amount of an optional conductivity imparting agent such as conductive carbon, metal oxide, or ionic conductive agent is blended therewith, and the resulting paint is dapped. It can be used by laminating by any method such as spraying or roll coating.

  On the other hand, for the brush-shaped charging member, a conventional fiber-impregnated fiber such as acrylic, nylon, polyester, etc., which has been used in the past, is impregnated with fluorine, and then implanted using a conventional method. Can be produced. Further, after various fibers are formed on the brush-shaped charging member, fluorine impregnation treatment may be performed.

  The brush-shaped charging member referred to here may be any of a roller-shaped charging member and a brushed charging member, and the shape thereof is not particularly limited. Further, the magnetic brush-like charging member is a member in which ferrite, magite and the like having a magnetic force are radially arranged on the outer periphery of a cylinder containing a multipolar magnet. A brush is desirable.

  FIG. 4 is a schematic view showing another preferred embodiment of the image forming apparatus of the present invention. The image forming apparatus 200 is an image forming apparatus of a tandem type intermediate transfer system. In the housing 220, four electrophotographic photosensitive members 201a to 201d (for example, 201a is yellow, 201b is magenta, 201c is cyan, and 201d is black). Color images can be formed respectively) along the intermediate transfer belt 209 and arranged in parallel with each other.

  Conventionally, as a method for transferring a visible image onto a transfer paper such as paper, a transfer drum method for winding a transfer paper such as paper around a transfer drum and transferring the visible image on the photosensitive member to the transfer paper for each color, etc. It has been known. In this case, compared with the tandem intermediate transfer method, the transfer of the visible image from the photosensitive member to the intermediate transfer member required the intermediate transfer member to rotate a plurality of times. This is a promising transfer method in the future because it can transfer images from a plurality of photoconductors 201a to 201d by one rotation of 209 and can improve the transfer speed and can select a transfer medium as in the transfer drum method. .

  Here, the electrophotographic photoreceptors 201 a to 201 d mounted on the image forming apparatus 200 are the same as the electrophotographic photoreceptor 1. Note that the image forming apparatus 200 satisfies the condition of the above formula (1).

  Each of the electrophotographic photoreceptors 201a to 201d can be rotated in a predetermined direction (counterclockwise on the paper surface), and the charging rolls 202a to 202d, the developing devices 204a to 204d, and the primary transfer roll 210a along the rotation direction. To 210d and cleaning devices 215a to 215d are arranged. Each of the developing devices 204a to 204d can be supplied with toner of four colors, yellow, magenta, cyan, and black, stored in the toner cartridges 205a to 205d. Further, the primary transfer rolls 210a to 210d are in contact with the electrophotographic photosensitive members 201a to 201d via the intermediate transfer belt 209, respectively.

  Further, a laser light source (exposure device) 203 is disposed at a predetermined position in the housing 220. Laser light emitted from the laser light source 203 can be applied to the surfaces of the electrophotographic photosensitive members 201a to 201d after charging. Accordingly, charging, exposure, development, primary transfer, and cleaning are sequentially performed in the rotation process of the electrophotographic photosensitive members 201a to 201d, and the toner images of the respective colors are transferred onto the intermediate transfer belt 209 in an overlapping manner.

  The intermediate transfer belt 209 is supported with a predetermined tension by a drive roll 206, a backup roll 208, and a tension roll 207, and can rotate without causing deflection due to the rotation of these rolls. The secondary transfer roll 213 is disposed so as to contact the backup roll 208 via the intermediate transfer belt 209. The intermediate transfer belt 209 that has passed between the backup roll 208 and the secondary transfer roll 213 is cleaned by a cleaning blade 216 disposed in the vicinity of the drive roll 206, for example, and then repeatedly used for the next image forming process. Is done.

  Further, a tray (transfer medium tray) 211 is provided at a predetermined position in the housing 220, and the transfer medium 230 such as paper in the tray 211 is transferred by the transfer roll 212 to the intermediate transfer belt 209 and the secondary transfer roll. Then, the sheet is sequentially transferred between the two fixing rolls 214 that are in contact with each other and between the two fixing rolls 214 and then discharged to the outside of the housing 220.

  In the above description, the case where the intermediate transfer belt 209 is used as the intermediate transfer member has been described. However, the intermediate transfer member may have a belt shape (for example, an endless belt shape) like the intermediate transfer belt 209. It may be a drum shape. When a belt-shaped configuration such as the intermediate transfer belt 209 is adopted as the intermediate transfer member, generally the film thickness of the belt is preferably 50 to 500 μm, more preferably 60 to 150 μm. In addition, the film thickness of a belt can be suitably selected according to the hardness of material. When a drum-shaped configuration is adopted as the intermediate transfer member, it is preferable to use a cylindrical substrate formed of aluminum, stainless steel (SUS), copper, or the like as the substrate. If necessary, an elastic layer can be coated on the cylindrical substrate, and a surface layer can be formed on the elastic layer.

  The medium to be transferred in the present invention is not particularly limited as long as it is a medium for transferring a toner image formed in the shape of an electrophotographic photosensitive member. For example, when transferring directly from an electrophotographic photosensitive member to paper or the like, paper or the like is a transfer medium, and when an intermediate transfer member is used, the intermediate transfer member is a transfer medium.

  As the material of the endless belt, heat such as polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene phthalate, PC / polyalkylene phthalate (PAT) blend material, ethylene tetrafluoroethylene copolymer (ETFE), etc. A semiconductive endless belt made of a plastic resin has been proposed.

  Japanese Patent No. 2560727, Japanese Patent Application Laid-Open No. 5-77252, etc. propose an intermediate transfer member in which ordinary carbon black is dispersed as a conductive fine powder in a polyimide resin.

  Since the polyimide resin is a material having a high Young's modulus, it is less likely to be deformed by driving (stress of a support roll, a cleaning blade, etc.), so that it becomes an intermediate transfer body in which image defects such as color misregistration are unlikely to occur. A polyimide resin is usually obtained as a polyamic acid solution by polymerizing a substantially equimolar amount of tetracarboxylic dianhydride or its derivative and a diamine in a solvent. As tetracarboxylic dianhydride, what is shown by the following general formula (IV) is mentioned, for example.

［式中、Ｒは、脂肪族鎖式炭化水素基、脂肪族環式炭化水素基及び芳香族炭化水素基、並びにこれらの炭化水素基に置換基が結合した基からなる群より選ばれる４価の有機基を示す。］

[Wherein, R is a tetravalent group selected from the group consisting of an aliphatic chain hydrocarbon group, an aliphatic cyclic hydrocarbon group, an aromatic hydrocarbon group, and a group in which a substituent is bonded to these hydrocarbon groups. An organic group of ]

  Specific examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, and 3,3 ′, 4,4′-biphenyltetracarboxylic acid. Acid dianhydride, 2,3,3 ′, 4-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid Dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2′-bis (3,4-dicarboxyphenyl) sulfonic dianhydride, perylene-3,4,9,10 -Tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, ethylenetetracarboxylic dianhydride, etc. are mentioned.

On the other hand, specific examples of the diamine include 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, 3,3′-dichlorobenzidine, 4,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenylsulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 3,3′-dimethyl-4,4′-biphenyldiamine, benzidine, 3,3′-dimethylbenzidine 3,3′-dimethoxybenzidine, 4,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenylpropane, 2,4-bis (β-aminotert-butyl) toluene, bis (p-β-amino- Tert-butylphenyl) ether, bis (p-β-methyl-δ-aminophenyl) benzene, bis p- (1,1-dimethyl-5-amino-benzyl) benzene, 1-isopropyl-2,4-m-phenylenediamine, m-xylylenediamine, p-xylylenediamine, di (p-aminocyclohexyl) methane , Hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylene, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2,11-diaminododecane, 1 , 2-bis-3-aminopropoxyethane, 2,2-dimethylpropylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 3-methylheptamethylenediamine, 5-methylnonamethylenediamine, 2, 17-diaminoeicosadecane, 1,4-diaminocyclohexane, 1,10-diamino-1,10-dimethyldecane, 12-diaminooctadecane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, _{piperazine, H 2 N (CH 2)} 3 O (CH 2) 2 O (CH 2) NH 2, H 2 N (CH 2) 3 S (CH 2) 3 NH 2, H 2 N (CH 2) 3 N _{(CH 3) 2 (CH 2} ) 3 NH 2 and the like.

  As the solvent for the polymerization reaction of tetracarboxylic dianhydride and diamine, a polar solvent is preferably used from the viewpoint of solubility. As the polar solvent, N, N-dialkylamides are preferable, and specific examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide, which are low molecular weight compounds thereof. N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethyl sulfoxide, hexamethylphosphortriamide, N-methyl-2-pyrrolidone, pyridine, tetramethylene sulfone, dimethyltetramethylene sulfone and the like. These can be used alone or in combination of two or more.

  The intermediate transfer member contains oxidized carbon black in a polyimide resin. Oxidized carbon black can be obtained by oxidizing carbon black to give an oxygen-containing functional group (for example, carboxyl group, quinone group, lactone group, hydroxyl group, etc.) to the surface.

  This oxidation treatment is an air oxidation method in which contact is caused to react with air in a high temperature atmosphere, a method in which it reacts with nitrogen oxide or ozone at room temperature, and a method in which ozone oxidation is performed at low temperature after air oxidation at high temperature. Etc.

  Specific examples of the oxidized carbon include MA100 (pH 3.5, volatile matter 1.5%), MA100R (pH 3.5, volatile matter 1.5%), MA100S (pH 3.5, manufactured by Mitsubishi Chemical). Volatility 1.5%), # 970 (pH 3.5, volatile content 3.0%), MA11 (pH 3.5, volatile content 2.0%), # 1000 (pH 3.5, volatile content 3) 0.02), # 2200 (pH 3.5, volatile content 3.5%), MA 230 (pH 3.0, volatile content 1.5%), MA 220 (pH 3.0, volatile content 1.0%) # 2650 (pH 3.0, volatile content 8.0%), MA7 (pH 3.0, volatile content 3.0%), MA8 (pH 3.0, volatile content 3.0%), OIL7B ( pH 3.0, volatile content 6.0%), MA 77 (pH 2.5, volatile content 3.0%), # 2350 (p 2.5, volatile content 7.5%), # 2700 (pH 2.5, volatile content 10.0%), # 2400 (pH 2.5, volatile content 9.0%), Detexa Printex 150T (pH 4.5, volatile content 10.0%), Special Black 350 (pH 3.5, volatile content 2.2%), Special Black 100 (pH 3.3, volatile content 2.2%), Special Black 250 (pH 3.1, volatile content 2.0%), Special Black 5 (pH 3.0, volatile content 15.0%), Special Black 4 (pH 3.0, volatile content 14.0%), Special Black 4A (pH 3.0, volatile content 14.0%), Special Black 550 (pH 2.8, volatile content 2.5%), Special Black 6 (pH 2.5, volatile content 18.0%), Same color black FW2 0 (pH 2.5, volatile content 20.0%), same color black FW2 (pH 2.5, volatile content 16.5%), same color black FW2V (pH 2.5, volatile content 16.5%), Cabot Corporation MONARCH1000 (pH 2.5, volatile content 9.5%), MONARCH 1300 (pH 2.5, volatile content 9.5%) manufactured by Cabot, MONARCH 1400 (pH 2.5, volatile content 9.0%) manufactured by Cabot, MOGUL-L (pH 2.5, volatile matter 5.0%), REGAL400R (pH 4.0, volatile matter 3.5%);

  The oxidation-treated carbon black obtained in this way has an excessive current flowing in part, and is not easily affected by oxidation due to repeated voltage application. Furthermore, due to the effect of the oxygen-containing functional group attached to the surface, the dispersibility in polyimide is high, the resistance variation can be reduced, the electric field dependency is also reduced, and the electric field concentration due to the transfer voltage is less likely to occur. .

  As a result, resistance degradation due to transfer voltage is prevented, uniformity of electrical resistance is improved, electric field dependency is small, resistance change due to the environment is small, and image quality defects such as whitening of the paper running part occur. The intermediate transfer member can obtain a suppressed high image quality. If at least two types are included, these oxidized carbon blacks preferably have substantially different conductivity, such as the degree of oxidation treatment, DBP oil absorption, specific surface area by the BET method using nitrogen adsorption, etc. Use materials with different physical properties.

  When two or more types of carbon blacks having different physical properties are added as described above, for example, carbon black exhibiting high conductivity is preferentially added, and then carbon black having low conductivity is added to adjust the surface resistivity. It is possible.

  Specific examples of the oxidized carbon black include SPECIAL BLACK4 (Degussa, pH 3.0, volatile content: 14.0%), SPECIAL BLACK250 (Degussa, pH 3.1, volatile content: 2.0%), and the like. Is mentioned. The content of the oxidized carbon black is preferably about 10 to 50% by weight, more preferably 12 to 30% by weight, based on the polyimide resin. If this content is less than 10% by weight, the uniformity of electrical resistance may decrease, and the decrease in surface resistivity during durable use may increase. On the other hand, if it exceeds 50% by weight, the desired resistance value may be obtained. Is not preferred, and it is not preferable because it becomes brittle as a molded product.

  The intermediate transfer body made of polyimide resin in which oxidized carbon black is dispersed performs a step of preparing a polyamic acid solution in which oxidized carbon black is dispersed, a step of forming a film (layer) on the inner surface of a cylindrical mold, and imide conversion It can be obtained through a process.

  About the manufacturing method of the polyamic acid solution which disperse | distributed 2 or more types of oxidation treatment carbon black, the said acid dianhydride component and diamine component are contained in the dispersion liquid which disperse | distributed 2 or more types of oxidation treatment carbon black beforehand in the solvent. Method of dissolving and polymerizing Two or more types of oxidized carbon black are each dispersed in a solvent to prepare two or more types of carbon black dispersions, and the acid anhydride component and the diamine component are dissolved and polymerized in this dispersion. Thereafter, a method of mixing each polyamic acid solution, etc. can be considered, and a polyamic acid solution in which carbon black is dispersed is prepared by selecting as appropriate.

  The polyamic acid solution thus obtained is supplied to and spread on the inner surface of the cylindrical mold to form a film, and the polyamic acid is obtained by imide conversion by heating. In this heating step for imide conversion, an intermediate transfer member having good flatness can be obtained by performing imide conversion under heating conditions that are maintained at a constant temperature for 0.5 hour or more. This will be described in detail below.

  A polyamic acid solution is supplied to the inner surface of the cylindrical mold. This supply method can be performed by appropriately selecting a method using a dispenser, a method using a die, or the like. The surface state of the inner peripheral surface of the cylindrical mold used at this time is preferably mirror-finished.

  A coating film having a uniform film thickness is formed by appropriately selecting the polyamide acid solution supplied in this manner, such as a method of centrifugal molding while heating, a method of molding using a bullet-shaped traveling body, a method of rotational molding, and the like. Subsequently, the mold with the coating film formed on the inner peripheral surface is heated in a dryer and heated until imide conversion, or after removing the solvent until the shape can be maintained as a belt, from the inner surface of the mold A method may be considered in which, after peeling and replacing the outer surface of a metal cylinder, the entire cylinder is heated to perform imide conversion. In order to obtain an intermediate transfer member having suitable flatness and outer surface accuracy, it is preferable to remove the solvent until it can be held as a belt, and then replace it with a metal cylinder to perform imide conversion.

  The heating conditions in the step of removing the solvent are not particularly limited as long as the removal of the solvent proceeds, but preferably at 80 to 200 ° C. for 0.5 to 5 hours. Next, the molded product that can retain its shape as a belt is peeled off from the inner peripheral surface of the mold. At this time, a mold release process can be performed on the inner peripheral surface of the mold.

  Next, the molded product heated and cured until it can be held as a belt shape is replaced with the outer surface of the metal cylinder, and the replaced cylinder is heated to advance the imide conversion reaction of the polyamic acid.

  The metal cylinder used at this time preferably has a linear expansion coefficient larger than that of the polyimide resin. By making the outer diameter of the cylinder smaller than the inner diameter of the polyimide molding by a predetermined amount, heat setting can be performed and a uniform film thickness can be obtained. Thus, an endless belt without unevenness can be obtained. The surface roughness (Ra) of the outer surface of the metal cylinder used at this time is preferably 1.2 to 2.0 μm. If the surface roughness (Ra) of the outer surface of the metal cylinder is smaller than 1.2 μm, the belt-shaped intermediate transfer member obtained because the metal cylinder itself is too smooth will not slip due to contraction in the axial direction of the belt. This is performed in this step, which causes variations in film thickness and a decrease in flatness accuracy.

  Also, if the surface roughness (Ra) of the outer surface of the metal cylinder is larger than 2.0 μm, the outer surface of the metal cylinder is transferred to the inner surface of the belt-shaped intermediate transfer member, and unevenness is generated on the outer surface, thereby causing image defects. generate. The surface roughness (Ra) of the outer surface of the belt-shaped intermediate transfer member made of polyimide resin in which carbon black thus obtained is dispersed is 1.5 μm or less.

  The surface roughness is measured according to JIS B601. When the surface roughness (Ra) of the intermediate transfer member is larger than 1.5 μm, image defects such as roughening occur. This is because the voltage applied locally during transfer and the electric field due to peeling discharge concentrate on the convex part of the belt surface, the surface of this part is altered and a new conductive path is created, resulting in a decrease in resistance. However, the density is lowered, and it seems that the entire image looks cluttered.

  It is preferable that the heating process for imide conversion is performed at a heating temperature of 220 to 280 ° C. and a heating time of 0.5 to 2 hours. Although depending on the composition of the polyimide resin, the amount of shrinkage is the largest in this region under the heating conditions during imide conversion.Thus, by gently performing the shrinkage in the axial direction of the belt, film thickness variation and flatness A reduction in accuracy can be prevented.

  The intermediate transfer member that has undergone such a heating step has a flatness of 5 mm or less, preferably 3 mm or less. When the flatness is 5 mm or less, there is no roughness and color deviation is small. However, when the belt end is bent vertically, the intermediate transfer member will not break during use even if it is 5 mm or less, but it rarely remains after contacting the peripheral member. Further, when the flatness is 3 mm or less, the intermediate transfer member is not brought into contact with the peripheral member during use and there is almost no color shift.

(Process cartridge)
Next, a process cartridge equipped with an electrophotographic photosensitive member will be described.
FIG. 5 is a schematic view showing a preferred embodiment of the process cartridge of the present invention.

  In the process cartridge 300, a charging device 3, a developing device 7, a cleaning device 11, and a static eliminator 13 are combined in a case 301 together with an electrophotographic photosensitive member 1 using a mounting rail 303. The process cartridge 300 is not provided with an exposure device, but an opening 305 for exposure is formed in the case 301. The electrophotographic photosensitive member 1 is the above-described electrophotographic photosensitive member, and includes a conductive substrate, an undercoat layer formed on the conductive substrate, and a photosensitive layer formed on the undercoat layer. The process cartridge 300 is configured such that the film thickness and volume resistivity of the undercoat layer satisfy the condition expressed by the above formula (1).

  The process cartridge 300 is detachable from the image forming apparatus main body including the transfer device 12, the fixing device 15, and other components not shown, and constitutes the image forming apparatus together with the image forming apparatus main body. To do.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all. In this example, first, an electrophotographic photosensitive member and a developer were produced, and an image forming apparatus was produced using them.

(Photoreceptor 1)
First, an aluminum substrate (conductive substrate) having a diameter of 30 mm, a length of 340 mm, and a thickness of 1 mm was prepared.

A mixture of 100 parts by weight of zinc oxide (average particle diameter 70 nm, prototype manufactured by Teika) and 500 parts by weight of toluene was stirred, and N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane ( 1.5 parts by weight of KBM603 (manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and the mixture was further stirred for 2 hours. Thereafter, toluene was distilled off under reduced pressure and baked at 150 ° C. for 2 hours, and the zinc oxide was subjected to a surface treatment. As a result of IR measurement of this zinc oxide by the KBr method, it was confirmed that (I ₁ / I ₂ ) was 1 or less (I ₁ is the characteristic of the infrared absorption spectrum of the zinc oxide particles obtained after the surface treatment) The absorption intensity in the absorption band 3270 cm ⁻¹ is represented, and I ₂ represents the absorption intensity in the characteristic absorption band 880 cm ⁻¹ of the infrared absorption spectrum of the zinc oxide particles obtained after the surface treatment.

  60 parts by weight of zinc oxide thus surface-treated is used as a curing agent, 15 parts by weight of blocked isocyanate (Sumijoule 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) and butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) It melt | dissolved in 85 weight part of methyl ethyl ketone with 15 weight part, and was set as the solution. 38 parts by weight of this solution was mixed with 25 parts by weight of methyl ethyl ketone, and dispersion treatment was performed for 2 hours with a sand mill using 1 mmφ glass beads to obtain a dispersion. As a catalyst, 0.005 part by weight of dioctyltin dilaurate and 3.5 parts by weight of a silicone resin ball having an average particle diameter of 4.5 μm (Tospearl 145, manufactured by GE Toshiba Silicone Co., Ltd.) for imparting light scattering to the obtained dispersion. Were added and stirred to obtain a coating solution for forming an undercoat layer. This coating solution was applied onto an aluminum substrate by a dip coating method and dried at 160 ° C. for 100 minutes to cure the coating film to form an undercoat layer having a thickness of 23 μm.

The volume resistivity ρ (Ω · cm) of the undercoat layer was measured as follows. A vertical cross section with respect to the axis of a φ0.7 mm tungsten rod was pressed perpendicularly to the undercoat layer coated on the aluminum substrate at a pressure of 100 g, the aluminum substrate was set to 0 V, −10 V was applied to the tungsten rod, The current value I (A) after 2 seconds was measured. Substituting the thickness d (μm) of the undercoat layer and the current value I (A) into the following formula, the volume resistivity ρ (Ω · cm) was calculated.
Volume resistivity ρ (Ω · cm) = − 10 × 0.035 ² × 3.14 / (I × d × 10 ⁻⁴ )
The obtained results are shown in Table 10 together with the thickness of the undercoat layer.

  Next, hydroxygallium phthalocyanine having diffraction peaks at positions of at least 7.6 ° and 28.2 ° in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using CuKα rays was prepared. A mixture of 4 parts by weight of the hydroxygallium phthalocyanine, 1 part by weight of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nihon Unicar) as a binder resin, and 120 parts by weight of n-butyl acetate was used in a sand mill for 4 hours. Dispersion treatment was performed to obtain a charge generation layer forming coating solution. The obtained coating solution was dip-coated on the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm.

Next, 1 part by weight of tetrafluoroethylene resin particles and 0.02 part by weight of the fluorine-based graft polymer are sufficiently stirred and mixed together with 5 parts by weight of tetrahydrofuran and 2 parts by weight of toluene to obtain a tetrafluoroethylene resin particle suspension. It was. Next, 4 parts by weight of N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1 ′] biphenyl-4,4′-diamine as a charge transport material, and bisphenol Z-type polycarbonate 6 parts by weight of a resin (viscosity average molecular weight 40,000) was mixed and dissolved in 23 parts by weight of tetrahydrofuran and 10 parts by weight of toluene, and then the tetrafluoroethylene resin particle suspension was added and mixed with stirring. Thereafter, using a high-pressure homogenizer (trade name LA-33S, manufactured by Nanomizer Co., Ltd.) equipped with a through-type chamber having a fine flow path, the dispersion treatment with the pressure increased to 400 Kgf / cm ² was repeated 6 times, and then 4 An ethylene resin particle dispersion was obtained. Further, 0.2 parts by weight of 2,6-di-t-butyl-4-methylphenol was mixed to obtain a coating solution for forming a charge transport layer. This coating solution was applied onto the charge generation layer and dried at 115 ° C. for 40 minutes to form a charge transport layer having a thickness of 25 μm. The obtained electrophotographic photoreceptor was designated as photoreceptor 1.

(Photoreceptor 2)
The undercoat layer and the charge generation layer are formed on the conductive substrate in the same manner as in Example 1 except that the undercoat layer is prepared so that the film thickness and volume resistivity are as shown in Table 10. did. Next, 4 parts by weight of N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1 ′] biphenyl-4,4′-diamine as a charge transport material, bisphenol Z-type polycarbonate resin (Viscosity average molecular weight 40,000) 6 parts by weight, tetrahydrofuran 80 parts by weight and 2,6-di-tert-butyl-4-methylphenol 0.2 parts by weight were mixed to obtain a charge transport layer forming coating solution. . This coating solution was applied onto the charge generation layer and dried at 115 ° C. for 40 minutes to form a charge transport layer. The thickness of the charge transport layer was 20 μm.

  Next, a protective layer (surface layer) was formed using a protective layer forming coating solution described below. That is, 2 parts by weight of a compound represented by the following formula (V), 2 parts by weight of methyltrimethoxysilane, 1 part by weight of tetramethoxysilane and 0.3 part by weight of colloidal silica, 5 parts by weight of isopropyl alcohol, 3 parts by weight of tetrahydrofuran and It was dissolved in a mixed solution of 0.3 parts by weight of distilled water, 0.5 parts by weight of ion exchange resin (Amberlyst 15E) was added, and the mixture was stirred at room temperature for 24 hours for hydrolysis.

A solution obtained by filtering and separating the ion exchange resin from the hydrolyzed solution was mixed with 0.1 parts by weight of aluminum trisacetylacetonate (Al (aqaq) ₃ ) and 3,5-di-t-butyl-4-hydroxytoluene (BHT). ) 0.4 part by weight was added to prepare a coating solution for forming a protective layer. The coating solution was applied on the charge transport layer by a ring-type dip coating method and air-dried at room temperature for 30 minutes. Then, it heat-processed at 150 degreeC for 1 hour, the coating film was hardened, and the protective layer with a film thickness of about 3 micrometers was formed.

(Photoreceptor 3)
100 parts by weight of zinc oxide (average particle size 70 nm, prototype manufactured by Teika) is stirred and mixed with 500 parts by weight of toluene, 1.5 parts by weight of a silane coupling agent (KBM603, manufactured by Shin-Etsu Chemical Co., Ltd.) is added, and 2 hours Stir. Thereafter, toluene was distilled off under reduced pressure, baked at 150 ° C. for 2 hours, and further baked at 200 ° C. for 1 hour to perform surface treatment. As a result of IR measurement of this zinc oxide by the KBr method, it was confirmed that (I ₁ / I ₂ ) was 0.9 (I ₁ is the infrared absorption spectrum of the zinc oxide particles obtained after the surface treatment). represents the absorption intensity at the characteristic absorption band 3270cm ^-1, _{I 2} represents the absorption intensity in the infrared absorption spectrum of the characteristic absorption band 880 cm ^-1 of the zinc oxide particles obtained after the surface treatment).

  60 parts by weight of zinc oxide subjected to this surface treatment, 15 parts by weight of blocked isocyanate (Sumijoule 3175, manufactured by Sumitomo Bayern Urethane) as a curing agent, and 15 parts by weight of butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) Dissolved in 85 parts by weight of methyl ethyl ketone. 38 parts by weight of the solution and 25 parts by weight of methyl ethyl ketone were mixed. Furthermore, dispersion was obtained by dispersing for 2 hours in a sand mill using 1 mmφ glass beads. As a catalyst, 0.005 part by weight of dioctyltin dilaurate and 0.01 part by weight of silicone oil SH29PA (manufactured by Toray Dow Corning Silicone) were added to the resulting dispersion to obtain a coating liquid for forming an undercoat layer. This coating solution was applied onto an aluminum substrate having a diameter of 30 mm, a length of 340 mm, and a thickness of 1 mm by a dip coating method, followed by drying and curing at 160 ° C. for 100 minutes to form an undercoat layer having a thickness of 25 μm. Table 10 shows the film thickness of the undercoat layer and the volume resistivity measured in the same manner as in the case of the photoreceptor 1.

  Next, a charge generation layer and a charge transport layer were formed in the same manner as in Example 1. The obtained electrophotographic photoreceptor was designated as photoreceptor 3.

(Photoreceptor 4)
100 parts by weight of zinc oxide (MZ300, manufactured by Teika) and 500 parts by weight of toluene are stirred and mixed, and 5 parts by weight of γ-aminopropyltrimethoxysilane (KBM903, manufactured by Shin-Etsu Chemical Co., Ltd.) is added as a silane coupling agent. Stir for 2 hours. Thereafter, toluene was distilled off under reduced pressure and baked at 150 ° C. for 2 hours, and further baked at 200 ° C. for 1 hour. As a result of IR measurement of this zinc oxide by KBr method, as a result of IR measurement of this zinc oxide by KBr method, (I ₁ / I ₂ ) was confirmed to be 0.5 (I ₁ is represents the absorption intensity at the characteristic absorption band 3270cm ^-1 in the infrared absorption spectrum of the zinc oxide particles obtained after the surface treatment, I ₂ is the characteristic absorption band 880 cm ^-1 in the infrared absorption spectrum of the zinc oxide particles obtained after the surface treatment Represents absorption intensity). Further, the absorption intensity at the characteristic absorption band 2927cm ^-1 was confirmed to be 0.6 with respect to the absorption intensity at the characteristic absorption band 880 cm ^-1.

  60 parts by weight of surface-treated zinc oxide, 15 parts by weight of blocked isocyanate (Sumijoule 3175, manufactured by Sumitomo Bayern Urethane) as a curing agent, and 15 parts by weight of butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) as methyl ethyl ketone Dissolved in 85 parts by weight. 38 parts by weight of the solution and 25 parts by weight of methyl ethyl ketone were mixed. Furthermore, dispersion was obtained by dispersing for 2 hours in a sand mill using 1 mmφ glass beads. As a catalyst, 0.005 part by weight of dioctyltin dilaurate and 0.01 part by weight of silicone oil SH29PA (manufactured by Toray Dow Corning Silicone) were added to the resulting dispersion to obtain a coating liquid for forming an undercoat layer. This coating solution was applied onto an aluminum substrate having a diameter of 30 mm, a length of 340 mm, and a thickness of 1 mm by a dip coating method, followed by drying and curing at 160 ° C. for 100 minutes to form an undercoat layer having a thickness of 20 μm. Table 10 shows the film thickness of the undercoat layer and the volume resistivity measured in the same manner as in the case of the photoreceptor 1.

  Next, a charge generation layer was formed on the undercoat layer. First, 15 parts by weight of oxytitanyl phthalocyanine having a diffraction peak at a position of at least 27.3 ° in a Bragg angle (2θ ± 0.2 °) of an X-ray diffraction spectrum using Cukα rays as a charge generating substance, a binder resin As a mixture, 10 parts by weight of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nihon Unicar) and 300 parts by weight of n-butyl acetate were obtained. This mixture was dispersed in a sand mill for 4 hours using 1 mmφ glass beads. The obtained dispersion was dip-coated on the undercoat layer as a coating solution for forming a charge generation layer and dried to form a charge generation layer having a thickness of 0.2 μm.

  Furthermore, 4 parts by weight of N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1 ′] biphenyl-4,4′-diamine and bisphenol Z polycarbonate resin (molecular weight 40,000) 6 A coating solution prepared by adding 80 parts by weight of chlorobenzene and dissolved in parts by weight was applied onto the charge generation layer and dried at 130 ° C. for 40 minutes to form a charge transport layer having a thickness of 25 μm. The obtained electrophotographic photoreceptor was designated as photoreceptor 4.

(Photoreceptor 5)
The outer surface of the ED tube aluminum substrate is subjected to liquid honing using spherical alumina fine powder having a D50 of 30 μm to obtain a 30 mmφ conductive substrate roughened to a center line average roughness Ra of 0.18 μm. It was.

  Next, 4 parts by weight of polyvinyl butyral resin (S-REC BM-S, manufactured by Sekisui Chemical Co., Ltd.) was dissolved in 170 parts by weight of n-butyl alcohol. To the solution, 30 parts by weight of an organic zirconium compound (acetylacetone zirconium butyrate) and 3 parts by weight of an organic silane compound (γ-aminopropyltrimethoxysilane) were added, mixed and stirred to obtain a coating solution for forming an undercoat layer. The obtained coating solution was applied to the outer peripheral surface of the substrate using a dip coating apparatus and air-dried at room temperature for 5 minutes, and then the substrate was heated to 50 ° C. over 10 minutes, and then 50 ° C. and 85% RH. It was put in a constant temperature and humidity chamber (dew point 47 ° C.) and subjected to a humidifying and curing accelerating treatment for 20 minutes. Then, it put into the hot air dryer and dried for 10 minutes at 170 degreeC, and formed the undercoat layer of film thickness of 1.0 micrometer. Table 10 shows the film thickness of the undercoat layer and the volume resistivity measured in the same manner as in the case of the photoreceptor 1.

  A charge generation layer and a charge transport layer were formed on the undercoat layer in the same manner as in Example 1. The obtained electrophotographic photoreceptor was designated as photoreceptor 5.

(Photoreceptor 6)
An undercoat layer was formed on an aluminum substrate in the same manner as in Example 1 except that the thickness of the undercoat layer was 1.0 μm. Table 10 shows the film thickness of the undercoat layer and the volume resistivity measured in the same manner as in the case of the photoreceptor 1. Next, a charge generation layer and a charge transport layer were formed on the undercoat layer in the same manner as in Example 1. The obtained electrophotographic photoreceptor was designated as photoreceptor 6.

(Photoreceptor 7)
Toluene solution containing 100 parts by weight of zinc oxide (Nano Tek ZnO, manufactured by CI Kasei Co., Ltd.) and 10% by weight of N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane as a coupling agent 10 parts by weight and 200 parts by weight of toluene were mixed and refluxed for 2 hours with stirring. Thereafter, the system was depressurized to 10 mmHg to distill off the toluene, and heat treatment was performed at 135 ° C. for 2 hours to subject the zinc oxide particles to a surface treatment. As a result of IR measurement of this zinc oxide by the KBr method, it was confirmed that (I ₁ / I ₂ ) was 0.5 (I ₁ is the infrared absorption spectrum of the zinc oxide particles obtained after the surface treatment). represents the absorption intensity at the characteristic absorption band 3270cm ^-1, _{I 2} represents the absorption intensity in the infrared absorption spectrum of the characteristic absorption band 880 cm ^-1 of the zinc oxide particles obtained after the surface treatment).

  After mixing 33 parts by weight of surface-treated zinc oxide particles, 6 parts by weight of blocked isocyanate (Sumijoule 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) and 25 parts by weight of methyl ethyl ketone, butyral resin (BM-1, Sekisui) 5 parts by weight of chemical), 3 parts by weight of silicone balls (Tospearl 120, manufactured by Toshiba Silicone) and 0.01 parts by weight of leveling agent (silicone oil SH29PA, manufactured by Toray Dow Corning Silicone) were added to the above mixture. Then, a dispersion treatment for 2 hours was performed in a sand mill to obtain a coating solution for forming an undercoat layer. Further, the above coating solution is applied to the outer peripheral surface of a cylindrical aluminum substrate having a diameter of 30 mm, a length of 404 mm, and a wall thickness of 1 mm by dip coating, followed by drying and curing at 150 ° C. for 30 minutes, and subbing with a film thickness of 20 μm. A layer was formed. Table 10 shows the film thickness of the undercoat layer and the volume resistivity measured in the same manner as in the case of the photoreceptor 1.

  Next, a charge generation layer and a charge transport layer were formed on the undercoat layer in the same manner as in Example 1. The obtained electrophotographic photoreceptor was designated as photoreceptor 7.

(Developer 1)
<Manufacture of toner base particles>
In the production of toner mother particles, first, a resin fine particle dispersion, a colorant dispersion, and a release agent dispersion were prepared. Next, toner mother particles were produced using them. The details will be described below.

  Each physical property value was measured by the following method. That is, the particle size distribution of the toner and the composite particles was measured using a multisizer (manufactured by Nikka Kisha Co., Ltd.) with an aperture diameter of 100 μm.

Further, the average shape factor ML ² / A of the toner and the composite particles means a value calculated by the following formula. In the case of a true sphere, ML ² / A = 100.
ML ² / A = (maximum length) ² × π × 100 / (area × 4)
As a specific method for obtaining the average shape factor, a toner image is taken from an optical microscope into an image analyzer (LUZEX (III), manufactured by Nireco), the equivalent circle diameter is measured, the maximum length and area are obtained, The value of ML ² / A in the above formula was determined for the particles.

<Resin fine particle dispersion>
A nonionic surfactant (370 parts by weight of styrene, 30 parts by weight of n-butyl acrylate, 8 parts by weight of acrylic acid, 24 parts by weight of dodecanethiol, and 4 parts by weight of carbon tetrabromide) Emulsion polymerization in a flask in which 6 parts by weight of Nonipol 400 (manufactured by Sanyo Chemical Co., Ltd.) and 10 parts by weight of an anionic surfactant (Neogen SC, Daiichi Kogyo Seiyaku Co., Ltd.) are dissolved in 550 parts by weight of ion-exchanged water. While slowly mixing for 10 minutes, 50 parts by weight of ion-exchanged water in which 4 parts by weight of ammonium persulfate was dissolved was added thereto. After carrying out nitrogen substitution, it heated with the oil bath until the contents became 70 degreeC, stirring the inside of a flask, and emulsion polymerization was continued as it was for 5 hours. As a result, a resin fine particle dispersion in which resin particles having an average particle diameter of 150 nm, Tg = 58 ° C., and weight average molecular weight Mw = 11500 was obtained. The solid content concentration of this dispersion was 40% by weight.

<Colorant dispersion (1)>
60 parts by weight of carbon black (Mogal L: manufactured by Cabot), 6 parts by weight of nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.), and 240 parts by weight of ion-exchanged water are mixed and dissolved, and homogenizer The mixture was stirred for 10 minutes using (Ultra Turrax T50: manufactured by IKA). Thereafter, a colorant dispersion (1) in which colorant (carbon black) particles having an average particle diameter of 250 nm were dispersed was prepared by dispersion treatment with an optimizer.

<Colorant dispersion (2)>
60 parts by weight of Cyan pigment B15: 3, 5 parts by weight of a nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.), and 240 parts by weight of ion-exchanged water were mixed and dissolved, and a homogenizer (Ultra Turrax) The mixture was stirred for 10 minutes using T50 (manufactured by IKA). Thereafter, a colorant dispersion (2) in which colorant (Cyan pigment) particles having an average particle diameter of 250 nm were dispersed was prepared by dispersing with an optimizer.

<Colorant dispersion (3)>
60 parts by weight of Magenta pigment R122, 5 parts by weight of a nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) and 240 parts by weight of ion-exchanged water are mixed and dissolved, and a homogenizer (Ultra Turrax T50: IKA) is mixed. For 10 minutes. Thereafter, a colorant dispersion (3) in which colorant (Magenta pigment) particles having an average particle diameter of 250 nm were dispersed was prepared by dispersing with an optimizer.

<Colored dispersion (4)>
90 parts by weight of Yellow pigment Y180, 5 parts by weight of nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.), and 240 parts by weight of ion-exchanged water are mixed and dissolved, and a homogenizer (Ultra Turrax T50: The mixture was stirred for 10 minutes using IKA. Thereafter, a colorant dispersion (4) in which colorant (Yellow pigment) particles having an average particle diameter of 250 nm were dispersed was prepared by dispersion treatment with an optimizer.

<Releasing agent dispersion>
100 parts by weight of paraffin wax (HNP0190: manufactured by Nippon Seiwa Co., Ltd., melting point 85 ° C.), 5 parts by weight of cationic surfactant (Sanisol B50: manufactured by Kao Corporation), and 240 parts by weight of ion-exchanged water Mixed. It was dispersed for 10 minutes in a round stainless steel flask using a homogenizer (Ultra Turrax T50: manufactured by IKA). Thereafter, a dispersion treatment was performed using a pressure discharge type homogenizer to prepare a release agent dispersion liquid in which release agent particles having an average particle diameter of 550 nm were dispersed.

<Toner mother particle K1>
234 parts by weight of resin fine particle dispersion, 30 parts by weight of colorant dispersion (1), 40 parts by weight of release agent dispersion, 0.5 parts by weight of polyaluminum hydroxide (Pho2S manufactured by Asada Chemical Co., Ltd.) 600 parts by weight of ion-exchanged water was mixed. It was further mixed and dispersed in a round stainless steel flask using a homogenizer (Ultra Turrax T50: manufactured by IKA). Then, it heated to 40 degreeC, stirring the inside of a flask in the oil bath for heating. After maintaining at 40 ° C. for 30 minutes, it was confirmed that aggregated particles having a D50 of 4.5 μm were produced. Further, the temperature of the heating oil bath was raised and maintained at 56 ° C. for 1 hour, and D50 was 5.3 μm. Thereafter, 26 parts by weight of the resin fine particle dispersion was added to the dispersion containing the aggregate particles, and then the temperature of the heating oil bath was raised to 50 ° C. and held for 30 minutes. The dispersion containing the aggregated particles was added with 1N sodium hydroxide to adjust the pH of the system to 7.0, and then the stainless steel flask was sealed and heated to 80 ° C. while continuing stirring using a magnetic seal. And held for 4 hours. After cooling, the toner base particles were separated by filtration, washed four times with ion exchange water, and then lyophilized to obtain toner base particles K1. The volume average particle diameter D50 of the toner base particles K1 is 5.9 μm, and the average shape factor ML ² / A is 132.

<Toner base particle C1>
Toner base particles C1 were obtained in the same manner as toner base particles K1, except that the colored particle dispersion (2) was used instead of the colored particle dispersion (1). The volume average particle diameter D50 of the toner base particles C1 is 5.8 μm, and the average shape factor ML ² / A is 131.

<Toner mother particle M1>
Toner mother particles M1 were obtained in the same manner as toner mother particles K1, except that colored particle dispersion (3) was used instead of colored particle dispersion (1). The toner mother particles M1 had a volume average particle diameter D50 of 5.5 μm and an average shape factor ML ² / A of 135.

<Toner base particle Y1>
Toner base particles Y1 were obtained in the same manner as toner base particles K1, except that the colored particle dispersion (4) was used instead of the colored particle dispersion (1). The volume average particle size D50 of the toner base particles Y1 is 5.9 μm, and the average shape factor ML ² / A is 130.

<Carrier>
14 parts by weight of toluene, 2 parts by weight of a styrene / methacrylate copolymer (component ratio: 90/10), and 0.2 parts by weight of carbon black (R330: manufactured by Cabot Corporation) were stirred with a stirrer for 10 minutes, A dispersed coating solution was prepared. Next, this coating solution and 100 parts by weight of ferrite particles (average particle size: 50 μm) were put in a vacuum degassing kneader and stirred at 60 ° C. for 30 minutes. Further, the carrier was obtained by depressurizing while depressurizing while heating and drying. This carrier had a volume resistivity of 10 ¹¹ Ωcm when an applied electric field of 1000 V / cm was applied.

  100 parts by weight of each of the toner base particles K1, C1, M1, and Y1 is 1 part by weight of rutile-type titanium oxide (particle size 20 nm, n-decyltrimethoxysilane treated), silica (particle size 40 nm, silicone oil treated, Gas phase oxidation method) 2.0 parts by weight, cerium oxide (average particle size 0.7 μm) 1 part by weight, zinc stearate solution (higher fatty acid alcohol (higher fatty acid alcohol having a molecular weight of 700) and zinc stearate in a weight ratio of 5 : 1 by grinding with a jet mill at a ratio of 1 and an average particle size of zinc stearate of 8.0 μm) was blended with a 5 L Henschel mixer at a peripheral speed of 30 m / s × 15 minutes. Thereafter, coarse particles were removed using a sieve having an opening of 45 μm to obtain toner 1. Further, developer 1 was obtained by stirring 100 parts by weight of carrier and 5 parts by weight of toner 1 with a V-blender for 20 minutes at 40 rpm and sieving with a sieve having an opening of 212 μm.

(Developer 2)
<Toner mother particles K2>
234 parts by weight of the resin fine particle dispersion, 30 parts by weight of the colorant dispersion (1), 40 parts by weight of the release agent dispersion, 0.5 parts by weight of polyaluminum hydroxide (Pho2S manufactured by Asada Chemical Co., Ltd.) And 600 parts by weight of ion-exchanged water were mixed. It was further mixed and dispersed in a round stainless steel flask using a homogenizer (Ultra Turrax T50: manufactured by IKA). Then, it heated to 40 degreeC, stirring the inside of a flask in the oil bath for heating. After maintaining at 40 ° C. for 30 minutes, it was confirmed that aggregated particles having a D50 of 4.5 μm were produced. Further, the temperature of the heating oil bath was raised and maintained at 56 ° C. for 1 hour, and D50 was 5.3 μm. Thereafter, 26 parts by weight of the resin fine particle dispersion was added to the dispersion containing the aggregate particles, and then the temperature of the heating oil bath was raised to 50 ° C. and held for 30 minutes. After adding 1N sodium hydroxide to the dispersion containing the aggregate particles and adjusting the pH of the system to 5.0, the stainless steel flask is sealed, and the stirring is continued to 95 ° C. using a magnetic seal. Heated and held for 4 hours. After cooling, the toner base particles were filtered off, washed four times with ion exchange water, and then freeze-dried to obtain toner base particles K2. The volume average particle diameter D50 of the toner base particles K2 is 5.8 μm, and the average shape factor ML ² / A is 109.

<Toner base particle C2>
Toner base particles C2 were obtained in the same manner as K2 except that the colored particle dispersion (2) was used instead of the colored particle dispersion (1). The volume average particle size D50 of the toner base particles C2 is 5.7 μm, and the average shape factor ML ² / A is 110.

<Toner mother particle M2>
Toner mother particles M2 were obtained in the same manner as K2 except that the colored particle dispersion (3) was used instead of the colored particle dispersion (1). The volume average particle diameter D50 of the toner base particles M2 is 5.6 μm, and the average shape factor ML ² / A is 114.

<Toner base particle Y2>
Toner mother particles Y2 were obtained in the same manner as above except that the colored particle dispersion (4) was used instead of the colored particle dispersion (1). The volume average particle diameter D50 of the toner base particles Y2 is 5.8 μm, and the average shape factor ML ² / A is 108.

  Instead of toner base particles K1, C1, M1, Y1, toner base particles K2, C2, M2, Y2 are used, and aluminum oxide (average particle size 0) is used instead of 1 part by weight of cerium oxide (average particle size 0.7 μm). Toner 2 was prepared in the same manner as Toner 1 except that 1 .mu.m) was used. A developer 2 was obtained in the same manner as the developer 1 except that the toner 2 was used.

(Developer 3)
Polyester resin (bisphenol type, weight average molecular weight (Mw) 14000, glass transition temperature (Tg): 62 ° C.) 89 parts by weight, polypropylene wax (trade name: Biscol 660P, manufactured by Sanyo Chemical Industries), 5 parts by weight, and carbon black (Cabot BPL) 6 parts by weight were mixed. The mixture was kneaded with a biaxial extruder, pulverized with a jet mill, and then classified with a wind classifier to produce toner particles having a volume average particle diameter D50 of 8.5 μm. Next, 100 parts by weight of the toner particles, 1.0 part by weight of colloidal silica (trade name: R972, manufactured by Nippon Aerosil Co., Ltd.), and 0.5 weight of cerium oxide (average particle diameter: 0.2 μm) as abrasive fine particles. Parts were stirred and mixed using a Henschel mixer to prepare a toner composition.

  On the other hand, 14 parts by weight of toluene, 2 parts by weight of a styrene-methacrylate copolymer (component ratio: 90/10) and 0.2 parts by weight of carbon black (trade name: R330, manufactured by Cabot Corporation) were stirred with a stirrer for 10 minutes. A coating solution was prepared. This coating solution and 100 parts by weight of ferrite particles (average particle size: 50 μm) are placed in a vacuum degassing kneader and stirred at 60 ° C. for 30 minutes, and then degassed by depressurization while heating and dried. A carrier was prepared.

  After 7 parts by weight of the toner composition and 100 parts by weight of the carrier were stirred for 20 minutes at a rotation speed of 40 rpm using a V blender, coarse particles were removed using a sieve having an opening of 177 μm, and a two-component developer (development) Agent 3) was obtained.

(Example 1)
An image forming apparatus (printer manufactured by Fuji Xerox, modified Docu Center Color C400) having the configuration shown in FIG. 1, including the above-described electrophotographic photoreceptor 1, developer 1, and cleaning device having a cleaning blade, was produced. The cleaning blade had a thickness of 2 mm, a hardness of 75 °, and a rebound resilience at 51 ° C. of 51%. Further, the cleaning blade was disposed at a contact angle of 25 ° with respect to the electrophotographic photosensitive member, and the pressing pressure of the blade was 20 g / cm.

(Examples 2-8 and Comparative Examples 1-10)
Image formation of Examples 2 to 8 and Comparative Examples 1 to 10 was performed in the same manner as in Example 1 except that the pressing pressure of the electrophotographic photosensitive member, developer, and cleaning blade was changed to the combinations shown in Tables 11 and 12. A device was made.

(Image formation test)
Using the image forming apparatuses of Examples 1 to 8 and Comparative Examples 1 to 10, 70,000 sheets of image forming tests were performed in an environment of high temperature and high humidity (28 ° C., 85% RH). Observing the occurrence of black spots due to leaks during the test, the image quality was evaluated by the occurrence of black spots. The obtained results are shown in Tables 11 and 12.

1 is a schematic diagram showing a preferred embodiment of an image forming apparatus of the present invention. 1 is a schematic cross-sectional view showing an example of an electrophotographic photoreceptor according to the present invention. It is a schematic diagram which shows other suitable embodiment of the image forming apparatus of this invention. It is a schematic diagram which shows other suitable embodiment of the image forming apparatus of this invention. It is a schematic diagram showing a preferred embodiment of the process cartridge of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electrophotographic photoreceptor, 3 ... Charging apparatus, 5 ... Exposure apparatus, 7 ... Developing apparatus, 9 ... Transfer apparatus,
DESCRIPTION OF SYMBOLS 11 ... Cleaning apparatus, 21 ... Conductive substrate, 22 ... Undercoat layer, 24 ... Photosensitive layer, 100, 110, 200, ... Image forming apparatus.

Claims (10)

A charging step for charging an electrophotographic photosensitive member having a conductive substrate, an undercoat layer formed on the conductive substrate, and a photosensitive layer formed on the undercoat layer;
Exposing the charged electrophotographic photoreceptor to form an electrostatic latent image on the electrophotographic photoreceptor; and
A developing step of developing the electrostatic latent image with a developer to form a toner image;
A transfer step of transferring the toner image from the electrophotographic photosensitive member to a transfer medium;
A cleaning step of removing toner remaining on the electrophotographic photosensitive member after the transfer step;
Have
An image forming method, wherein the film thickness and volume resistivity of the undercoat layer satisfy a condition represented by the following formula (1).
log ₁₀ (ρ)> − 3 · log ₁₀ (d) +13 (1)
[In the formula (1), ρ represents volume resistivity (Ω · cm), and d represents the film thickness (μm) of the undercoat layer. ] An electrophotographic photoreceptor having a conductive substrate, an undercoat layer formed on the conductive substrate, and a photosensitive layer formed on the undercoat layer;
A charging device for charging the electrophotographic photosensitive member;
An exposure apparatus that exposes the charged electrophotographic photoreceptor to form an electrostatic latent image on the electrophotographic photoreceptor;
A developing device for developing the electrostatic latent image with a developer to form a toner image;
A transfer device for transferring the toner image from the electrophotographic photosensitive member to a transfer medium;
A cleaning device for removing toner remaining on the electrophotographic photosensitive member after transfer;
With
An image forming apparatus, wherein a film thickness and volume resistivity of the undercoat layer satisfy a condition represented by the following formula (1).
log ₁₀ (ρ)> − 3 · log ₁₀ (d) +13 (1)
[In the formula (1), ρ represents volume resistivity (Ω · cm), and d represents the film thickness (μm) of the undercoat layer. ] Metal oxide particles in which the undercoat layer is surface-treated using a silane coupling agent having at least a structure in which an amino group is bonded to a carbon atom at the end of a molecular chain, and satisfies the condition represented by the following formula (2) The image forming apparatus according to claim 2, further comprising:
(I ₁ / I ₂ ) ≦ 1.0 (2)
[In Formula (2), I ₁ represents the absorption intensity in the characteristic absorption band 3270 cm ⁻¹ of the infrared absorption spectrum of the metal oxide particles obtained after the surface treatment, and I ₂ represents the metal oxide particles obtained after the surface treatment. It represents the absorption intensity in the characteristic absorption band 880 cm ⁻¹ of the infrared absorption spectrum. ]   The image forming apparatus according to claim 2, wherein the silane coupling agent is a fluorine-free compound.   The image forming apparatus according to claim 2, wherein the metal oxide particles contain at least one selected from zinc oxide, titanium oxide, and tin oxide.   The image forming apparatus according to claim 2, wherein a thickness of the undercoat layer is greater than 15 μm.   7. The electrophotographic photosensitive member according to any one of claims 2 to 6, wherein the electrophotographic photosensitive member contains lubricating particles in a layer disposed on the side farthest from the conductive substrate of the photosensitive layer. Image forming apparatus.   The image forming apparatus according to claim 7, wherein the lubricating particles are fluorine resin particles.   The developer contains toner particles having a volume average particle diameter of 3 to 9 μm obtained by a polymerization method, and the cleaning device has a blade member that contacts the electrophotographic photosensitive member at a linear pressure of 10 to 150 g / cm. The image forming apparatus according to claim 2, wherein the image forming apparatus is provided. An electrophotographic photoreceptor having a conductive substrate, an undercoat layer formed on the conductive substrate, and a photosensitive layer formed on the undercoat layer;
A charging device for charging the electrophotographic photosensitive member;
With
A process cartridge, wherein a film thickness and volume resistivity of the undercoat layer satisfy a condition represented by the following formula (1).
log ₁₀ (ρ)> − 3 · log ₁₀ (d) +13 (1)
[In the formula (1), ρ represents volume resistivity (Ω · cm), and d represents the film thickness (μm) of the undercoat layer. ]

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