JP2023057031A - process cartridge - Google Patents

Abstract

To provide a process cartridge that can prevent fogging and form an image with an excellent gradation property regardless of a use environment.SOLUTION: A process cartridge has an electrophotographic photoreceptor that can be removably attached to an electrophotographic device body, and developing means that supplies toner to the surface of the photoreceptor. A surface protective layer of the electrophotographic photoreceptor contains conductive particles. The content of the conductive particles is 20.0 to 70.0 volume% of the entire volume of the surface protective layer. The volume resistivity of the surface protective layer is 1.0×109 to 1.0×1014 Ω cm. A toner particle has at least one polyvalent metal element selected from the group consisting of aluminum, magnesium, calcium, and iron. The total content of the polyvalent metal element in the toner particle measured by the inductively coupled plasma-atomic emission spectroscopy (ICP-AES) is 0.10 to 1.25 μmol/g.SELECTED DRAWING: None

Description

The present invention relates to a process cartridge used in copiers and printers using an electrophotographic system or an electrostatic recording system.

In recent years, printers and copiers are required to have higher image quality. Furthermore, since users use various environments, it is required to obtain stable image quality regardless of the usage environment.

In response to this demand, many toners produced by the emulsion aggregation method have been proposed in terms of wide material selectivity and easy control of the shape of toner particles. In the emulsion aggregation method, a resin particle dispersion is prepared by emulsion polymerization, forced emulsification, phase inversion emulsification, or the like, and a colorant dispersion is prepared by dispersing a colorant in a solvent. After that, they are mixed, an aggregate corresponding to the toner particle size is formed using an aggregating agent, and the aggregate is fused and coalesced by heating to produce a toner.

Polyvalent metal ions are generally used as aggregating agents, and the presence of metal ions derived from the aggregating agents in the toner particles can cause charges accumulated on the surfaces of the toner particles to leak. As a result, the toner charge-up phenomenon is suppressed, especially in a low-temperature, low-humidity environment where electric charge tends to accumulate, and the adverse effect of developing toner in the non-printing portion of the image due to poor charging of the toner (hereinafter referred to as "fogging"). ) can be suppressed. On the other hand, in a high-temperature, high-humidity environment with a lot of moisture in the atmosphere, the charge on the toner surface leaks and the amount of charge decreases, resulting in fog and images with excellent gradation. There was a problem. The excellent gradation means that the difference in color density of the image can be clearly visually recognized. Color density is expressed by increasing or decreasing the amount of toner per unit area on the image. In some cases, the amount of toner applied may increase or become extremely small, making it difficult to visually recognize subtle differences in color densities on the image.

In order to address such a problem, Patent Document 1 discloses a process cartridge in which emulsion aggregation toner and a photoreceptor having a surface protective layer containing specific conductive particles (hereinafter also referred to as "protective layer") are combined. Proposed. In Japanese Patent Laid-Open No. 2002-100001, image deletion in a high-temperature and high-humidity environment is improved by stabilizing the charging characteristics of the photoreceptor and improving the mechanical strength of the photoreceptor. can also work effectively.

JP 2009-229495 A

However, according to the study by the present inventors, even the configuration as disclosed in Japanese Patent Laid-Open No. 2002-200010 could not improve the deterioration of the gradation in a high-temperature, high-humidity environment. It is presumed that this is because the charging characteristics of the protective layer of the photoreceptor were not suitable. It is believed that there is still room for improvement in the properties and content of the conductive particles in the protective layer in order to obtain images with excellent gradation.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a process cartridge capable of suppressing fogging and forming an image with excellent gradation regardless of the usage environment.

A process cartridge according to the present invention is a process cartridge that is detachably attachable to an electrophotographic apparatus main body, the process cartridge has an electrophotographic photosensitive member and a toner containing portion containing toner, and and developing means for supplying the toner to the surface of a photoreceptor, the electrophotographic photoreceptor comprising a conductive support, and a photosensitive layer and a surface protective layer formed on the conductive support. and in this order, the surface protective layer contains conductive particles, and the content of the conductive particles is 20.0% by volume or more and 70.0% by volume or less of the total volume of the surface protective layer. and the surface protective layer has a volume resistivity of 1.0×10 ⁹ Ω·cm or more and 1.0×10 ¹⁴ Ω·cm or less, and the toner accommodated in the toner storage portion binds It has toner particles containing a resin and an external additive, the toner particles having at least one polyvalent metal element selected from the group consisting of aluminum, magnesium, calcium and iron, and coupled induced plasma emission. The total content of the polyvalent metal elements in the toner particles measured by spectroscopic analysis (ICP-AES) is 0.10 μmol/g or more and 1.25 μmol/g or less.

According to the present invention, it is possible to provide a process cartridge capable of suppressing fogging and forming an image with excellent gradation regardless of the usage environment.

FIG. 2 is a schematic diagram of a process cartridge used for toner evaluation in Examples. FIG. 4 is a diagram showing an example of a comb-shaped electrode for measuring volume resistivity of a photoreceptor according to the present invention; 4 is an example of an image for evaluating the gradation of the process cartridge according to the present invention; 1 is a STEM image showing an example of niobium-containing titanium oxide used in Examples. It is a schematic diagram showing an example of niobium-containing titanium oxide used in Examples.

In the present invention, the descriptions of "XX or more and YY or less" and "XX to YY" that represent numerical ranges mean numerical ranges including the lower and upper limits, which are endpoints, unless otherwise specified.
The present invention will be described in detail below.
The inventors of the present invention have found that, in a toner containing toner particles in which a polyvalent metal element is present, from the initial stage to the end of long-term continuous use,
(1) Excellent gradation can be obtained in a high-temperature and high-humidity environment;
(2) no fogging under high temperature and high humidity environment;
(3) no fog due to charge-up in a low temperature and low humidity environment;
We conducted an intensive study on

As a result, a process cartridge having a photoreceptor, a toner containing section containing toner, and developing means for supplying toner to the surface of the photoreceptor,
The photoreceptor has a conductive support, and a photosensitive layer and a surface protective layer formed on the conductive support in this order, and the surface protective layer contains conductive particles. , the content of the conductive particles is 20.0% by volume or more and 70.0% by volume or less of the total volume of the surface protective layer, and the surface protective layer has a volume resistivity of 1.0 × 10 ⁹ Ω· cm or more and 1.0×10 ¹⁴ Ω·cm or less,
The toner contained in the toner containing portion has toner particles containing a binder resin and an external additive, and the toner particles contain at least one selected from the group consisting of aluminum, magnesium, calcium, and iron. and the total content of the polyvalent metal elements in the toner particles is 0.10 μmol/g or more and 1.25 μmol as measured by coupled-inductive plasma atomic emission spectrometry (ICP-AES) / g or less,
It has been found that, regardless of the use environment, it is possible to suppress fogging and form an image having excellent gradation.

The reason why the effects of the present invention are exhibited by the above is considered as follows.
Image gradation expresses the difference in color density by increasing or decreasing the amount of toner per unit area developed on the photosensitive member in the process cartridge. The amount of toner to be developed is controlled by the potential of the electrostatic latent image formed on the surface of the photoreceptor and the charge amount of the toner. It is important that the charge amount distribution is high and sharp. For example, in a high-temperature, high-humidity environment with a large amount of moisture in the atmosphere, the amount of toner charge tends to decrease, and the amount of toner developed on the photoreceptor tends to increase, resulting in subtle electrostatic latent images. It becomes difficult to obtain a difference in density with respect to the potential difference. In addition, it becomes difficult to control the density of low-density images such as halftones, and when the potential of the electrostatic latent image drops below a certain value, the developability of the toner suddenly decreases, resulting in a phenomenon in which the image density becomes extremely low. easier to do.

The present inventors found that by adding an appropriate amount of conductive particles to the surface protective layer of the photoreceptor and controlling the volume resistivity of the surface protective layer, the charge on the surface of the photoreceptor during development can be reduced to a small portion. can be injected into the toner. Furthermore, with respect to the toner, the amount of the polyvalent metal element present in the toner particles was controlled to appropriately control the balance between the charge injection property and the charge leak property. In addition, the inventors have found that by combining these, it is possible to inject a very small portion of the charge on the surface of the photoreceptor into the toner during development, thereby increasing the charge amount of the toner and sharpening the charge amount distribution. As a result, it is possible to provide a process cartridge capable of obtaining an image with excellent gradation regardless of the usage environment and suppressing the occurrence of fogging even after long-term use.

The photoreceptor according to the present invention has a conductive support, a photosensitive layer, and a protective layer which is a surface layer. The protective layer contains conductive particles, and the content of the conductive particles is 20.0% by volume or more and 70.0% by volume or less of the total volume of the protective layer. Furthermore, it is characterized in that the volume resistivity of the protective layer is 1.0×10 ⁹ Ω·cm or more and 1.0×10 ¹⁴ Ω·cm or less. Although the protective layer contains a large amount of conductive particles, the volume resistivity is maintained relatively high. It is possible to have the toner inject charge.

If the content of the conductive particles is less than 20.0% by volume, the charge injection property of the toner according to the present invention is lowered, so the charge amount of the toner during development is low, resulting in a decrease in gradation and fogging. easier to do. On the other hand, if the content of the conductive particles exceeds 70%, the protective layer itself becomes brittle, and the surface of the photoreceptor is likely to be scratched over long-term use. As a result, the charge uniformity of the photoreceptor deteriorates, and gradation deterioration and fogging tend to occur. A more preferable content of the conductive particles is 40.0% by volume or more and 70.0% by volume or less of the protective layer.

Further, the volume resistivity of the protective layer is 1.0×10 ⁹ Ω·cm or more and 1.0×10 ¹⁴ Ω·cm or less. If the volume resistivity of the protective layer is less than 1.0×10 ⁹ Ω·cm, the resistance of the protective layer is so low that it becomes difficult to maintain the potential and the gradation tends to deteriorate. If the volume resistivity of the protective layer exceeds 1.0×10 ¹⁴ Ω·cm, the resistance of the protective layer is too high, and the injection chargeability of the toner is remarkably deteriorated.

More preferably, the protective layer has a volume resistivity of 1.0×10 ¹⁰ Ω·cm or more and 1.0×10 ¹⁴ Ω·cm or less. The volume resistivity of the protective layer can be controlled, for example, by the particle size of the conductive particles. The number average particle diameter of the conductive particles is preferably 40 nm or more and 300 nm or less, more preferably 100 nm or more and 250 nm or less. When the number average particle size of the conductive particles is less than 40 nm, the specific surface area of the conductive particles increases, and moisture adsorption increases in the vicinity of the conductive particles on the surface of the protective layer, and the volume resistivity of the protective layer decreases. easier to do. If the number average particle diameter of the conductive particles exceeds 300 nm, the dispersion of the particles in the protective layer is deteriorated, and the area of the interface with the binder resin is reduced, the resistance at the interface is increased, and the charge injection property is deteriorated. easier to do.

The conductive particles contained in the protective layer include metal oxide particles such as titanium oxide, zinc oxide, tin oxide, and indium oxide, with titanium oxide being preferred. Especially when it is anatase type titanium oxide, charge transfer in the protective layer becomes smooth and charge injection becomes good. The anatase-type titanium oxide preferably has a degree of anatase of 90% or more. The metal oxide particles may be doped with atoms such as niobium, phosphorus, aluminum, and oxides thereof, and particularly preferably titanium oxide particles containing niobium and having niobium unevenly distributed near the particle surface. is. The uneven distribution of niobium in the vicinity of the surface enables efficient transfer of charge. More specifically, with respect to the concentration ratio calculated as "niobium atom concentration/titanium atom concentration" at the center of the particle, "niobium atom concentration/titanium Titanium oxide particles having a concentration ratio calculated as "atomic concentration" of 2.0 times or more. The niobium atom concentration and titanium atom concentration are obtained by EDS analysis using a scanning transmission electron microscope (STEM). FIG. 4 shows an STEM image of an example of the niobium-containing titanium oxide particles used in the examples of the present invention. Although the details will be described later, the niobium-containing titanium oxide particles used in the present Examples are produced by coating titanium oxide particles, which serve as a core material, with niobium-containing titanium oxide and then firing the coated titanium oxide particles. Therefore, it is considered that the coated niobium-containing titanium oxide grows as niobium-doped titanium oxide by so-called epitaxial growth along the crystals of the titanium oxide of the core material. As shown in FIG. 4, the niobium-containing titanium oxide produced in this manner has a lower density near the surface than the density at the center of the particle, and is controlled to have a core-shell-like shape.

A STEM image of FIG. 4 is schematically shown in FIG. In such niobium-containing titanium oxide particles, the niobium/titanium atomic concentration ratio in the vicinity of the particle surface is higher than the niobium/titanium atomic concentration ratio in the center of the particle, and the niobium atoms are unevenly distributed in the vicinity of the particle surface. Specifically, the niobium/titanium atomic concentration ratio within 5% of the maximum diameter of the grain from the surface of the grain is at least 2.0 times the niobium/titanium atomic concentration ratio in the central portion of the grain. By increasing the ratio to 2.0 times or more, charges can easily move in the protective layer, and the charge injection property can be improved. If it is less than 2.0 times, it becomes difficult to transfer electric charges. In FIG. 5, reference numeral 31 indicates the central portion of the conductive particles, reference numeral 32 indicates the vicinity of the surface of the conductive particles, reference numeral 33 indicates X-rays for analyzing the central portion of the conductive particles, and reference numeral 34. indicates an X-ray that analyzes the inside of 5% of the particle diameter from the surface of the conductive particles.

The preferred niobium atom content is preferably 0.5% by mass or more and 15.0% by mass or less, and 2.6% by mass or more and 10.0% by mass or less, relative to the mass of the niobium atom-containing titanium oxide particles. is more preferable.

The toner according to the present invention will be described below.
The toner according to the present invention has toner particles containing a binder resin and an external additive, and the toner particles contain at least one polyvalent metal element selected from the group consisting of aluminum, magnesium, calcium and iron. have. Further, the total content of the polyvalent metal elements in the toner particles is 0.10 μmol/g or more and 1.25 μmol/g or less as measured by coupled-induced plasma-atomic emission spectrometry (ICP-AES). is.

The toner particles contain at least one polyvalent metal element selected from the group consisting of aluminum, magnesium, calcium and iron as injection sites for injecting charges from the photoreceptor. The electrical resistivities of these metal elements at 20° C. are aluminum 2.7×10 ⁻⁸ Ω・m, calcium 4.2×10 ⁻⁸ Ω・m, magnesium 4.5×10 ⁻⁸ Ω・m, and Iron is 9.7×10 ⁻⁸ Ω·m (quoted from “Kagaku Binran Basic Edition II” (revised 4th edition, edited by The Chemical Society of Japan, Maruzen, 1993, page 490)). The present inventors have confirmed that a toner containing these metal elements in an appropriate amount exhibits stable charge injection properties and charge retention properties. Although not used in the toner according to the present invention, for reference, metal elements with a lower electrical resistance include 1.7×10 ⁻⁸ Ω·m of copper and 1.6×10 ⁻⁸ Ω·m of silver (“ Kagaku Binran, Basic Edition II" (revised 4th edition, edited by The Chemical Society of Japan, Maruzen, 1993, page 490)).

If the content of at least one polyvalent metal element selected from the group consisting of aluminum, magnesium, calcium and iron in the toner particles is 0.10 μmol/g or more and 1.25 μmol/g or less, By combining with such a photoreceptor, the injection charging performance from the photoreceptor to the toner can be exhibited, and an image excellent in gradation can be obtained. If the content of the polyvalent metal element is less than 0.10 μmol/g, the charge injection property is significantly lowered, so that charge is not imparted to the toner and excellent gradation cannot be obtained. In addition, since the toner is easily charged up, the charge amount distribution of the toner is broadened in a low-temperature and low-humidity environment, and fogging is likely to occur. If the content of the polyvalent metal element exceeds 1.25 μmol/g, although the charge injection property is excellent, the charge tends to leak, resulting in deterioration of gradation and fogging.

A more detailed content of the polyvalent metal element is 0.50 μmol/g or less, more preferably 0.10 μmol/g or more and 0.32 μmol/g or less in the case of aluminum. 0.80 μmol/g or less for magnesium, 0.90 μmol/g or less for calcium, and 1.25 μmol/g or less for iron, the total content of these four polyvalent metal elements is preferably 0.10 μmol/g or more and 1.25 μmol/g or less. It is considered that the reason why the content range of the polyvalent metal element differs depending on the substance is related to the resistance value of the metal. Among the above, aluminum is preferable because it has a low electrical resistance value and exhibits excellent injectability even in a small amount.

The polyvalent metal element is preferably dispersed on the surface of the toner particles and inside the toner particles. Since the polyvalent metal element is also present inside the toner particles, the charge applied to the toner particle surfaces can be accumulated inside the toner particles. When the polyvalent metal element is present only on the surface of the toner particles, for example, by externally adding metal oxide particles to the toner particles, the leak property becomes too high, and the injected charge is transferred through members such as the toner carrier. is leaking, making it difficult to achieve the desired effect. Furthermore, through long-term use, the charging characteristics of the toner tend to fluctuate due to embedding or detachment of the external additive on the surface of the toner, which may make it difficult to obtain images with stable image quality.

As a means for allowing the polyvalent metal element to exist inside the toner particles, it is preferable to manufacture the toner particles by an emulsion aggregation method and to incorporate the polyvalent metal element into the particles via an aqueous medium. In the emulsion aggregation method, the metal element is ionized in an aqueous medium and then contained in the toner particles, so that the metal element can be uniformly dispersed. Furthermore, in emulsion aggregation toners, a carboxyl group is generally present in the molecular chain that constitutes the binder resin. Metal ions added as aggregating agents coordinate with carboxyl groups to form excellent conductive paths in the fine resin particles. Also, at this time, trivalent aluminum can be coordinated with a carboxyl group in a smaller amount than divalent magnesium, calcium, and iron, which can have mixed valences, and can exhibit better charge injection properties. .

The toner according to the present invention may contain wax. As the wax, known substances can be used, for example, low-molecular-weight polyethylene, low-molecular-weight polypropylene, microcrystalline wax, paraffin wax, aliphatic hydrocarbon waxes such as Fischer-Tropsch wax, and aliphatic hydrocarbon waxes such as oxidized polyethylene wax. Wax oxides or block copolymers thereof, waxes obtained by grafting a vinyl-based monomer such as styrene or acrylic acid to an aliphatic hydrocarbon wax, stearyl stearate, behenyl behenate, dibehenyl sebacate, Distearyl dodecanedioate, distearyl octadecanedioate, nonanediol dibehenate, ethylene glycol distearate, ethylene glycol dibehenate, butanediol dibehenate, butanediol distearate, pentaerythritol tetrabehenate, di Examples include saturated fatty acid ester compounds such as pentaerythritol hexastearate. Among them, an ester compound is preferable because it has a higher polarity and a lower electrical resistance value than a hydrocarbon wax, and thus has a function of assisting charge injection into the toner particles.

The configuration of the photoreceptor according to the present invention will be described in detail below.
<Protective layer>
When the protective layer serves as the surface layer, the surface of the protective layer contains the conductive particles of the present invention. The protective layer may contain a polymer of a compound having a polymerizable functional group and a resin. Examples of polymerizable functional groups include isocyanate groups, blocked isocyanate groups, methylol groups, alkylated methylol groups, epoxy groups, metal alkoxide groups, hydroxyl groups, amino groups, carboxy groups, thiol groups, carboxylic acid anhydride groups, carbon-carbon double bond groups, alkoxysilyl groups, silanol groups, and the like. A monomer having charge transport ability may be used as the compound having a polymerizable functional group. A compound having a polymerizable functional group may have a charge-transporting structure at the same time as the chain-polymerizable functional group.

Examples of resins include polyester resins, acrylic resins, phenoxy resins, polycarbonate resins, polystyrene resins, phenol resins, melamine resins, and epoxy resins. Among them, polycarbonate resins, polyester resins, and acrylic resins are preferred. Alternatively, the protective layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. The reaction at that time includes thermal polymerization reaction, photopolymerization reaction, radiation polymerization reaction, and the like. Examples of the polymerizable functional group possessed by the monomer having a polymerizable functional group include an acryloyl group and a methacryloyl group. A material having charge transport ability may be used as the monomer having a polymerizable functional group.

The protective layer can be formed by preparing a protective layer coating solution containing each of the above materials and a solvent, forming this coating film on the photosensitive layer, and drying and/or curing it. Solvents used in the coating liquid include alcohol solvents, ketone solvents, ether solvents, sulfoxide solvents, ester solvents, and aromatic hydrocarbon solvents.

The protective layer may contain additives such as an antioxidant, an ultraviolet absorber, a plasticizer, a leveling agent, a lubricating agent, and an abrasion resistance improver. Specifically, hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, boron nitride particles etc.
The average film thickness of the protective layer is preferably 0.2 μm or more and 5 μm or less, more preferably 0.5 μm or more and 3 μm or less.
The material and particle size of the conductive particles contained in the protective layer are as described above.

<Conductive support>
The photoreceptor according to the present invention has a conductive support having electrical conductivity. The shape of the support includes a cylindrical shape, a belt shape, a sheet shape, etc. Among them, a cylindrical support is preferable. Further, the surface of the support may be subjected to electrochemical treatment such as anodization, blasting treatment, cutting treatment, and the like. The material of the support is preferably metal, resin, glass, or the like. Examples of metals include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. Among them, an aluminum support using aluminum is preferable. In addition, it is preferable to impart conductivity to the resin or glass by treatment such as mixing or coating with a conductive material.

<Conductive layer>
In the photoreceptor according to the present invention, a conductive layer may be provided on the support. By providing the conductive layer, it is possible to cover scratches and irregularities on the surface of the support and to control reflection of light on the surface of the support. The conductive layer preferably contains conductive particles and a resin. Materials for the conductive particles include metal oxides, metals, and carbon black. Metal oxides include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, and bismuth oxide. Metals include aluminum, nickel, iron, nichrome, copper, zinc, silver and the like. Among these, metal oxides are preferably used as the conductive particles, and titanium oxide, tin oxide, and zinc oxide are particularly preferably used.

When a metal oxide is used as the conductive particles, the surface of the metal oxide may be treated with a silane coupling agent or the like, or the metal oxide may be doped with an element such as niobium, phosphorus, or aluminum or an oxide thereof. good. In particular, titanium oxide particles having niobium atoms unevenly distributed on the surface or near the surface are preferred.

Moreover, when a metal oxide is used as the conductive particles, the number average particle diameter thereof is preferably 1 nm or more and 500 nm or less, more preferably 3 nm or more and 400 nm or less.

Examples of resins include polyester resins, polycarbonate resins, polyvinyl acetal resins, acrylic resins, silicone resins, epoxy resins, melamine resins, polyurethane resins, phenol resins, and alkyd resins. In addition, the conductive layer may further contain silicone oil, resin particles, masking agents such as titanium oxide, and the like.

The conductive layer can be formed by preparing a conductive layer coating solution containing each of the above materials and a solvent, forming this coating film on a support, and drying the coating film. Solvents used in the coating liquid include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, aromatic hydrocarbon solvents and the like. Examples of the dispersion method for dispersing the conductive particles in the conductive layer coating liquid include methods using a paint shaker, a sand mill, a ball mill, and a liquid collision type high-speed disperser.

The average film thickness of the conductive layer is preferably 1 μm or more and 40 μm or less, and particularly preferably 3 μm or more and 30 μm or less.

<Undercoat layer>
In the photoreceptor according to the present invention, an undercoat layer may be provided on the support or the conductive layer. By providing the undercoat layer, the adhesion function between the layers is enhanced, and the charge injection blocking function can be imparted. The undercoat layer preferably contains a resin. Alternatively, the undercoat layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group.

Examples of resins include polyester resins, polycarbonate resins, polyvinyl acetal resins, acrylic resins, epoxy resins, melamine resins, polyurethane resins, phenol resins, polyvinyl phenol resins, alkyd resins, polyvinyl alcohol resins, polyethylene oxide resins, polypropylene oxide resins, and polyamide resins. , polyamic acid resins, polyimide resins, polyamideimide resins, cellulose resins, and the like.

Examples of the polymerizable functional group possessed by the monomer having a polymerizable functional group include an isocyanate group, a blocked isocyanate group, a methylol group, an alkylated methylol group, an epoxy group, a metal alkoxide group, a hydroxyl group, an amino group, a carboxyl group, a thiol group, Carboxylic anhydride groups, carbon-carbon double bond groups, and the like.

Moreover, the undercoat layer may further contain an electron transporting substance, a metal oxide, a metal, a conductive polymer, or the like for the purpose of enhancing electrical properties. Among these, electron transport substances and metal oxides are preferably used.
Examples of electron-transporting substances include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, halogenated aryl compounds, silole compounds, and boron-containing compounds. . An electron-transporting substance having a polymerizable functional group may be used as the electron-transporting substance, and an undercoat layer may be formed as a cured film by copolymerizing the electron-transporting substance with the above-mentioned monomer having a polymerizable functional group.
Metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, and silicon dioxide. Metals include gold, silver, and aluminum.

The metal oxide particles contained in the undercoat layer may be subjected to surface treatment using a surface treatment agent such as a silane coupling agent. A common method is used for the surface treatment of the metal oxide particles. Examples include dry methods and wet methods.
In the dry method, an alcohol aqueous solution, an organic solvent solution, or an aqueous solution containing a surface treatment agent is added while stirring the metal oxide particles in a mixer capable of high-speed stirring such as a Henschel mixer, and the particles are uniformly dispersed. It will be dried later.
In the wet method, the metal oxide particles and the surface treatment agent are stirred in a solvent or dispersed in a sand mill using glass beads or the like. After dispersion, the solvent can be removed by filtration or distillation under reduced pressure. done. After removing the solvent, baking is preferably performed at 100° C. or higher.

The undercoat layer may further contain additives, for example, known materials such as metal powder such as aluminum, conductive substances such as carbon black, charge transport substances, metal chelate compounds, and organometallic compounds. can be included.
Examples of charge-transporting substances include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, halogenated aryl compounds, silole compounds, and boron-containing compounds. . A charge-transporting substance having a polymerizable functional group may be used as the charge-transporting substance, and the undercoat layer may be formed as a cured film by copolymerizing the charge-transporting substance with the above monomer having a polymerizable functional group.

The undercoat layer can be formed by preparing an undercoat layer coating liquid containing each of the above materials and a solvent, forming this coating film on a support or a conductive layer, and drying and/or curing it. can.

Solvents used in the undercoat layer coating solution include organic solvents such as alcohols, sulfoxides, ketones, ethers, esters, aliphatic halogenated hydrocarbons, and aromatic compounds. In the present invention, it is preferable to use an alcohol-based or ketone-based solvent.
Dispersion methods for preparing the undercoat layer coating liquid include methods using a homogenizer, an ultrasonic disperser, a ball mill, a sand mill, a roll mill, a vibration mill, an attritor, and a liquid collision type high-speed disperser.

The average film thickness of the undercoat layer is preferably 0.1 μm or more and 10 μm or less, more preferably 0.1 μm or more and 5 μm or less.

<Photosensitive layer>
The photosensitive layer of the photoreceptor according to the present invention is mainly classified into (1) laminated photosensitive layer and (2) single layer photosensitive layer. (1) The laminated photosensitive layer is a photosensitive layer having a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance. (2) The single-layer type photosensitive layer is a photosensitive layer containing both a charge-generating substance and a charge-transporting substance.

(1) Laminated photosensitive layer The laminated photosensitive layer has a charge generation layer and a charge transport layer.

(1-1) Charge Generation Layer The charge generation layer preferably contains a charge generation substance and a resin.

Examples of charge-generating substances include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, and phthalocyanine pigments. Among these, azo pigments and phthalocyanine pigments are preferred. Among the phthalocyanine pigments, oxytitanium phthalocyanine pigments, chlorogallium phthalocyanine pigments, and hydroxygallium phthalocyanine pigments are preferred.
The content of the charge-generating substance in the charge-generating layer is preferably 40% by mass or more and 85% by mass or less, more preferably 60% by mass or more and 80% by mass or less, relative to the total mass of the charge-generating layer. preferable.

Resins include polyester resins, polycarbonate resins, polyvinyl acetal resins, polyvinyl butyral resins, acrylic resins, silicone resins, epoxy resins, melamine resins, polyurethane resins, phenol resins, polyvinyl alcohol resins, cellulose resins, polystyrene resins, and polyvinyl acetate resins. , polyvinyl chloride resin, and the like. Among these, polyvinyl butyral resin is more preferable.

The charge generation layer may further contain additives such as antioxidants and UV absorbers. Specific examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, and the like.

The charge-generating layer can be formed by preparing a charge-generating layer coating solution containing each of the above materials and a solvent, forming this coating film on a support, a conductive layer, or an undercoat layer, followed by drying. can. Solvents used in the coating liquid include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, aromatic hydrocarbon solvents and the like.

The average film thickness of the charge generation layer is preferably 0.1 μm or more and 1 μm or less, more preferably 0.15 μm or more and 0.4 μm or less.

(1-2) Charge Transport Layer The charge transport layer preferably contains a charge transport substance and a resin.

Examples of charge-transporting substances include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. . Among these, triarylamine compounds and benzidine compounds are preferred.
The content of the charge transport substance in the charge transport layer is preferably 25% by mass or more and 70% by mass or less, more preferably 30% by mass or more and 55% by mass or less, relative to the total mass of the charge transport layer. preferable.

Examples of resins include polyester resins, polycarbonate resins, acrylic resins, and polystyrene resins. Among these, polycarbonate resins and polyester resins are preferred. A polyarylate resin is particularly preferable as the polyester resin.
The content ratio (mass ratio) of the charge transport substance and the resin is preferably 4:10 to 20:10, more preferably 5:10 to 12:10.

The charge transport layer may also contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slipperiness agents and wear resistance improvers. Specifically, hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, boron nitride particles. etc.

The charge transport layer can be formed by preparing a charge transport layer coating solution containing each of the above materials and a solvent, forming this coating film on the charge generation layer, and drying the coating film. Solvents used in the coating liquid include alcohol solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents. Among these solvents, ether solvents and aromatic hydrocarbon solvents are preferred.

The average film thickness of the charge transport layer is preferably 3 μm or more and 50 μm or less, more preferably 5 μm or more and 40 μm or less, and particularly preferably 10 μm or more and 30 μm or less.

(2) Single-layer type photosensitive layer A single-layer type photosensitive layer is prepared by preparing a coating liquid for a photosensitive layer containing a charge-generating substance, a charge-transporting substance, a resin and a solvent, and applying this coating film to a support, a conductive layer, or an undercoat. It can be formed by forming on a layer and drying. The charge-generating substance, charge-transporting substance, and resin are the same as those exemplified in the above “(1) Laminated photosensitive layer”.

The binder resin, the wax as the release agent, the colorant, the charge control agent, and the external additive, which constitute the toner according to the present invention, will be described in detail below.

<Binder resin>
The binder resin of the toner according to the present invention is not particularly limited, and known ones can be used, but vinyl resins, polyester resins, and the like are preferable. Examples of vinyl resins, polyester resins and other binder resins include the following resins or polymers.
Homopolymers of styrene and substituted products thereof such as polystyrene and polyvinyltoluene; styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers, styrene-methyl acrylate copolymers, styrene - ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-methacrylic acid Ethyl copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer Styrenic copolymers such as coalescence, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, poly Vinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyamide resin, epoxy resin, polyacrylic resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin. These binder resins can be used alone or in combination. A styrenic copolymer is preferred.

It is preferable that these binder resins contain a carboxyl group because they coordinate with polyvalent metal ions to form excellent conductive paths as described above.
Polymerizable monomers containing a carboxy group include, for example, acrylic acid, methacrylic acid; α-alkyl derivatives or β-alkyl derivatives of acrylic acid or methacrylic acid such as α-ethylacrylic acid and crotonic acid; fumaric acid, maleic acid , citraconic acid, and itaconic acid; unsaturated dicarboxylic acids such as monoacryloyloxyethyl succinate, monoacryloyloxyethylene succinate, monoacryloyloxyethyl phthalate, and monomethacryloyloxyethyl phthalate monoester derivatives and the like.

As the polyester resin, those obtained by condensation polymerization of the following carboxylic acid component and alcohol component can be used.
Carboxylic acid components include terephthalic acid, isophthalic acid, phthalic acid, fumaric acid, maleic acid, cyclohexanedicarboxylic acid, and trimellitic acid. Alcohol components include bisphenol A, hydrogenated bisphenol, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, glycerin, trimethylolpropane, and pentaerythritol.
Moreover, the polyester resin may be a polyester resin containing a urea group. It is preferable not to cap the carboxyl groups such as terminals of the polyester resin.

<Wax>
The toner according to the present invention may contain wax as a release agent. Waxes that are preferably used are as described above. The content of the wax is preferably 5.0 parts by mass or more and 20.0 parts by mass or less with respect to 100.0 parts by mass of the binder resin or the polymerizable monomer forming the binder resin.

<Colorant>
Colorants are not particularly limited, and known ones can be used.

Yellow pigments include yellow iron oxide, navels yellow, naphthol yellow S, hansa yellow G, hansa yellow 10G, benzidine yellow G, benzidine yellow GR, quinoline yellow lake, permanent yellow NCG, condensed azo compounds such as tartrazine lake, Isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds are used. Specific examples include the following.
C. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 155, 168, 180, 185, 193.

Red pigments include red iron oxide, permanent red 4R, lithol red, pyrazolone red, watching red calcium salt, lake red C, lake red D, brilliant carmine 6B, brilliant carmine 3B, eoxin lake, rhodamine lake B, alizarin lake, and the like. condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specific examples include the following. C. I. Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221, 254.

Blue pigments include copper phthalocyanine compounds and their derivatives such as alkali blue lake, victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partial chloride, fast sky blue, and indanthrene blue BG, anthraquinone compounds, and basic dyes. A lake compound etc. are mentioned. Specific examples include the following. C. I. Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, 66.

Examples of black pigments include carbon black, aniline black, non-magnetic ferrite, magnetite, and those toned black using the above yellow, red, and blue colorants. These colorants can be used singly or in combination, or in the form of a solid solution.

If necessary, the colorant may be surface-treated with a substance that does not inhibit polymerization. The content of the colorant is preferably 3.0 parts by mass or more and 15.0 parts by mass or less with respect to 100.0 parts by mass of the binder resin or the polymerizable monomer forming the binder resin. .

<Charge control agent>
The toner according to the present invention may contain a charge control agent. A known charge control agent can be used. In particular, a charge control agent that has a high charging speed and can stably maintain a constant charge amount is preferred. Furthermore, when the toner particles are produced by a direct polymerization method, it is preferable to use a charge control agent that has a low polymerization inhibitory property and that does not substantially contain substances solubilized in an aqueous medium. Examples of charge control agents that control toner particles to be negatively chargeable include the following.

As organometallic compounds and chelate compounds, monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, oxycarboxylic acids and dicarboxylic acid metal compounds. Others include aromatic oxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, or esters, phenol derivatives such as bisphenol, and the like. Furthermore, urea derivatives, metal-containing salicylic acid-based compounds, metal-containing naphthoic acid-based compounds, boron compounds, quaternary ammonium salts, and calixarenes are included.

These charge control agents can be contained singly or in combination of two or more. The amount of the charge control agent to be added is preferably 0.01 parts by mass or more and 10.0 parts by mass or less with respect to 100.0 parts by mass of the binder resin.

<External Additives>
The toner according to the present invention may contain an external additive for the purpose of improving fluidity, charging property, blocking property and the like.
Examples of external additives include inorganic fine particles such as silica fine particles, alumina fine particles, and titanium oxide fine particles. These can be used individually by 1 type or in combination of 2 or more types. These inorganic fine particles are preferably surface-treated with a silane coupling agent, a titanium coupling agent, a higher fatty acid, a silicone oil, or the like, in order to improve heat-resistant storage stability and environmental stability.

The BET specific surface area of the external additive is preferably 10.0 m ² /g or more and 450.0 m ² /g or less. The BET specific surface area can be determined by a low temperature gas adsorption method using a dynamic constant pressure method according to the BET method (preferably the BET multipoint method). For example, using a specific surface area measuring device (trade name: Gemini 2375 Ver.5.0, manufactured by Shimadzu Corporation), nitrogen gas is adsorbed on the sample surface, and the BET multipoint method is used for measurement. BET specific surface area (m ² /g) can be calculated.

The total content of these various external additives is preferably 0.05 parts by mass or more and 5.0 parts by mass or less with respect to 100.0 parts by mass of the toner particles. The type and content of the external additive can be appropriately selected as long as the effects of the present invention are not impaired.

<Method for producing toner particles>
A known means can be used as a method for producing toner particles, and a kneading pulverization method or a wet production method can be used. A wet production method is preferable from the viewpoint of uniformity of particle size and shape controllability. Examples of the wet production method include a suspension polymerization method, a dissolution suspension method, an emulsion polymerization aggregation method, an emulsion aggregation method, and the like, and an emulsion aggregation method is more preferable. That is, the toner particles are preferably emulsion aggregation toner particles. This is because the polyvalent metal element is easily ionized in the aqueous medium, and the polyvalent metal element is easily contained in the toner particles when the binder resin is aggregated.
In the emulsion aggregation method, toner particles are produced through an emulsification step, an aggregation step, a fusion step, a cooling step, and a washing step of fine resin particles. Further, if necessary, a core-shell toner can be obtained by adding a shell forming process after the cooling process.

Emulsification process of fine resin particles Resin fine particles containing a binder resin as a main component can be prepared by a known method. For example, by dissolving the binder resin in an organic solvent and adding it to the aqueous medium, dispersing the particles in the aqueous medium together with the surfactant and polymer electrolyte using a dispersing machine such as a homogenizer, and then heating or reducing the pressure to remove the solvent. , a resin particle dispersion can be prepared. Any organic solvent can be used as long as it dissolves the resin, but tetrahydrofuran, ethyl acetate, chloroform and the like are preferable from the viewpoint of their high solubility.
Alternatively, the resin, surfactant, base, etc., are added to an aqueous medium, and emulsified and dispersed in an aqueous medium that does not substantially contain an organic solvent using a dispersing machine that applies high-speed shearing force, such as Clearmix, Homomixer, and Homogenizer. is preferable from the viewpoint of environmental load.

Surfactants used for emulsification are not particularly limited, and examples thereof include the following. Anionic surfactants such as sulfate-based, sulfonate-based, carboxylate-based, phosphate ester-based, and soap-based; cationic surfactants such as amine salt-based and quaternary ammonium salt-based; polyethylene glycol-based, alkylphenols Nonionic surfactants such as ethylene oxide adducts and polyhydric alcohols. The said surfactant may be used individually by 1 type, and may use 2 or more types together.

The median diameter of the fine resin particles based on volume distribution is preferably 0.05 to 1.0 μm, more preferably 0.05 to 0.4 μm. If it is 1.0 μm or less, it becomes easy to obtain toner particles having a median diameter of 4.0 to 7.0 μm based on volume distribution suitable as toner particles. The volume distribution-based median diameter can be measured by using a dynamic light scattering particle size distribution analyzer (Nanotrac UPA-EX150: manufactured by Nikkiso Co., Ltd.).

Aggregation step The aggregation step involves preparing a mixed liquid by mixing the resin fine particles described above and, if necessary, coloring agent fine particles, wax fine particles, etc., and then aggregating the particles contained in the prepared mixed liquid. This is the step of forming aggregates.
As the aggregating agent, inorganic salts and inorganic metal salts having a valence of 2 or more can be preferably used in addition to the surfactants having the polarity opposite to that of the surfactants described above. Inorganic metal salts, in particular, can be ionized by adding a polyvalent metal element to an aqueous medium, and can easily form coordinate bonds with carboxyl groups contained in the binder resin. This facilitates cohesion control and toner chargeability control. Specific examples of preferred inorganic metal salts include metal salts of calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, iron chloride, aluminum chloride, aluminum sulfate, polyiron chloride, polyaluminum chloride, and polywater. Inorganic metal salt polymers such as aluminum oxide. Among them, trivalent aluminum salts and polymers thereof are particularly preferred. Generally, in order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is preferably divalent rather than monovalent, and preferably trivalent or higher than divalent.

Addition of the flocculant is not particularly limited, but it is preferably added at 25 to 35° C., and then heated at a temperature not higher than the glass transition temperature (Tg) of the resin particles. If the mixing is carried out at a temperature below the Tg, fusion between the resin particles is suppressed, and aggregation proceeds in a stable state. As a result, the metal elements derived from the flocculant can be uniformly coordinated with the carboxy groups in the resin. The above mixing can be performed using a known mixing device, homogenizer, mixer, or the like.

The weight-average particle size of the aggregates formed here is not particularly limited, but is usually controlled to 4.0 μm to 7.0 μm so as to be approximately the same as the weight-average particle size of the toner particles to be obtained. good. The control can be easily performed, for example, by appropriately setting or changing the temperature during addition/mixing of the flocculant or the like and the stirring/mixing conditions. The particle size distribution of the toner particles can be measured by a particle size distribution analyzer (Coulter Multisizer III: manufactured by Beckman Coulter, Inc.) using the Coulter method.

- Fusion process The fusion process is a process for producing particles with a smooth aggregate surface by heating the above aggregates to a temperature higher than the glass transition temperature (Tg) of the resin to fuse them. A chelating agent, a pH adjuster, a surfactant, and the like can be appropriately added before the primary fusion step in order to prevent fusion between toner particles.
Examples of chelating agents include: alkali metal salts such as ethylenediaminetetraacetic acid (EDTA) and its Na salt; sodium gluconate, sodium tartrate, potassium and sodium citrate; nitrotriacetate (NTA) salts; Water-soluble polymers (polyelectrolytes).
The heating temperature may be between the glass transition temperature (Tg) of the resin contained in the aggregate and the temperature at which the resin thermally decomposes. As for the heating/fusion time, a short time is sufficient if the heating temperature is high, and a long time is required if the heating temperature is low. That is, the heating/fusion time depends on the heating temperature and cannot be defined unconditionally, but is generally 10 minutes to 10 hours.

- Cooling step The cooling step is a step of cooling the temperature of the aqueous medium containing the particles to a temperature lower than the glass transition temperature (Tg) of the resin used. If the cooling is not performed to a temperature lower than Tg, coarse particles may occur. A specific cooling rate is 0.1 to 50° C./min.

-Shell Formation Step If necessary, a shell formation step can be added before the washing and drying step described below. The shelling step is a step of adding fine resin particles to the particles prepared in the previous steps and making them adhere to form a shell.
The fine resin particles added here may have the same structure as the binder resin fine particles used in the core, or may have a different structure.

Washing and drying process The particles produced through the above process are washed and filtered with ion-exchanged water whose pH is adjusted with sodium hydroxide or potassium hydroxide, and then washed with ion-exchanged water and filtered multiple times. It can then be dried to obtain emulsion aggregation toner particles.

<Toner manufacturing method>
The toner according to the present invention may be toner particles to which an external additive is added. As an example of the external addition device, a double cone mixer, a V type mixer, a drum type mixer, a super mixer, an FM mixer (manufactured by Nippon Coke Kogyo Co., Ltd.), a nauta mixer, a mechanohybrid, or the like can be used. In order to control the coating state of the external additive, the toner can be prepared by adjusting the number of revolutions of the external additive device, the processing time, and the temperature and amount of water in the jacket.

<Process cartridge>
The process cartridge of the present invention includes the photoreceptor described above, a toner containing portion containing toner, and developing means for supplying toner to the surface of the photoreceptor, and is an electrophotographic apparatus main body. can be detachably attached to the

FIG. 1 shows an example of the schematic configuration of an electrophotographic apparatus having a process cartridge according to the present invention.
A cylindrical (drum-shaped) photosensitive member 1 is rotationally driven about a shaft 2 in the direction of an arrow at a predetermined peripheral speed (process speed). The surface of the photoreceptor 1 is charged to a predetermined positive or negative potential by the charging means 3 during the rotation process. Although FIG. 1 shows a roller charging method using a roller-type charging member, other charging methods such as a corona charging method, a proximity charging method, and an injection charging method may be employed. The surface of the charged photoreceptor 1 is irradiated with exposure light 4 from an exposure means (not shown) to form an electrostatic latent image corresponding to desired image information. The exposure light 4 is intensity-modulated light corresponding to time-series electrical digital image signals of target image information, and is output from image exposure means such as slit exposure or laser beam scanning exposure. The electrostatic latent image formed on the surface of the photoreceptor 1 is developed (regular development or reversal development) with toner accommodated in the developing means 5 to form a toner image on the surface of the photoreceptor 1 . A toner image formed on the surface of the photoreceptor 1 is transferred onto a transfer material 7 by a transfer means 6 . At this time, a bias voltage having a polarity opposite to the charge held by the toner is applied to the transfer means 6 from a bias power source (not shown). When the transfer material 7 is paper, the transfer material 7 is taken out from a paper supply unit (not shown) and fed between the photoreceptor 1 and the transfer means 6 in synchronism with the rotation of the photoreceptor 1. be. The transfer material 7 onto which the toner image has been transferred from the photoreceptor 1 is separated from the surface of the photoreceptor 1 and conveyed to a fixing means 8, where the toner image is fixed to form an image formed product (print, copy). printed out to the outside of the electrophotographic apparatus as

After the toner image has been transferred to the transfer material 7, the surface of the electrophotographic photosensitive member 1 is cleaned by cleaning means 9 to remove adhering matter such as toner (transferred residual toner). A recently developed cleaner-less system enables the transfer residual toner to be removed directly by a developing device or the like. Further, the surface of the electrophotographic photosensitive member 1 is subjected to static elimination by pre-exposure light 10 from pre-exposure means (not shown), and then repeatedly used for image formation. Incidentally, if the charging means 3 is a contact charging means using a charging roller or the like, the pre-exposure means is not necessarily required. In the present invention, among the components such as the electrophotographic photosensitive member 1, the charging means 3, the developing means 5 and the cleaning means 9, a plurality of components are housed in a container and integrally supported to form a process cartridge. . The process cartridge can be detachably attached to the main body of the electrophotographic apparatus. For example, at least one selected from the charging means 3, the developing means 5 and the cleaning means 9 is integrally supported together with the electrophotographic photosensitive member 1 to form a cartridge. A guide means 12 such as a rail of the electrophotographic apparatus main body can be used to form a process cartridge 11 detachably attachable to the electrophotographic apparatus main body. The exposure light 4 may be reflected light or transmitted light from an original when the electrophotographic apparatus is a copier or printer. Alternatively, the light may be light emitted by reading a document with a sensor, converting it into a signal, scanning a laser beam according to this signal, driving an LED array, driving a liquid crystal shutter array, or the like.

Methods for measuring physical properties of the photoreceptor and toner according to the present invention will be described below.
<Calculation of primary particle size of conductive particles>
First, the entire electrophotographic photosensitive member was immersed in methyl ethyl ketone (MEK) in a graduated cylinder and irradiated with ultrasonic waves to peel off the resin layer, and then the base of the electrophotographic photosensitive member was taken out. Next, the insoluble matter not dissolved in MEK (the photosensitive layer and the protective layer containing conductive particles) was filtered and dried in a vacuum dryer. Furthermore, the obtained solid was suspended in a mixed solvent of tetrahydrofuran (THF)/methylal at a volume ratio of 1:1, and after insoluble matter was filtered off, the filtrate was collected and dried in a vacuum dryer. By this operation, the conductive particles and the resin of the protective layer were obtained. Furthermore, the filter cake was heated to 500° C. in an electric furnace so that only the conductive particles were solid, and the conductive particles were recovered. In order to secure the necessary amount of conductive particles for measurement, a plurality of electrophotographic photoreceptors were subjected to the same treatment.
Part of the collected conductive particles is dispersed in isopropanol (IPA), the dispersion is dropped on a grid mesh with a support film (manufactured by JEOL Ltd., Cu150J), and a scanning transmission electron microscope (JEOL, JEM2800). Observation of the conductive particles was performed in the STEM mode. Observation was performed at a magnification of 500,000 to 1,200,000 times to facilitate calculation of the particle size of the conductive particles, and STEM images of 100 conductive particles were taken. At this time, the acceleration voltage was set to 200 kV, the probe size to 1 nm, and the image size to 1024×1024 pixels.
Using the obtained STEM image, the primary particle size was measured with image processing software "Image-Pro Plus (manufactured by Media Cybernetics)". First, using the straight line tool (Straight Line) on the toolbar, select the scale bar displayed at the bottom of the STEM image. If Set Scale is selected from the Analyze menu in that state, a new window opens and the pixel distance of the selected straight line is entered in the Distance in Pixels column. Enter the scale bar value (eg, 100) in the Known Distance column of the window, enter the scale bar unit (eg, nm) in the Unit of Measurement column, and click OK to complete the scale setting. Next, using a straight line tool, a straight line was drawn so as to have the maximum diameter of the conductive particles, and the particle diameter was calculated. The same operation was performed for 100 conductive particles, and the number average value of the obtained values (maximum diameter) was taken as the primary particle size of the conductive particles.

<Calculation of niobium atom/titanium atom concentration ratio>
A sample piece of 5 mm square was cut out from the photoreceptor, and cut to a thickness of 200 nm with an ultrasonic ultramicrotome (UC7, Leica) at a cutting speed of 0.6 mm/s to prepare a thin sample. This thin section sample was observed in the STEM mode of a scanning transmission electron microscope (JEOL, JEM2800) connected to an EDS analyzer (energy dispersive X-ray analyzer) at a magnification of 500,000 to 1,200,000 times. gone.
Among the cross sections of the conductive particles observed, a cross section of the conductive particles having a maximum diameter of approximately 0.9 to 1.1 times the primary particle diameter calculated above was selected visually. Subsequently, the spectrum of constituent elements of the cross section of the selected conductive particles was collected using an EDS analyzer to prepare an EDS mapping image. Spectral collection and analysis were performed using NSS (Thermo Fischer Scientific). The acquisition conditions were an acceleration voltage of 200 kV, a probe size of 1.0 nm or 1.5 nm so that the dead time was between 15 and 30, a mapping resolution of 256×256, and a frame number of 300. EDS mapping images were obtained for 100 cross sections of the conductive particles.

By analyzing the EDS mapping image obtained in this way, the niobium atomic concentration (atomic %) and the titanium atomic concentration (atomic %) in the center of the particle and inside 5% of the maximum diameter of the measured particle from the particle surface Calculate the ratio. Specifically, first, press the NSS "Line extraction" button, draw a straight line so that it becomes the maximum diameter of the particle, and the atomic concentration on the straight line from one surface to the other surface through the inside of the particle (atomic %) information is obtained. If the maximum diameter of the particles obtained at this time was in the range of less than 0.9 times or more than 1.1 times the primary particle diameter calculated above, it was excluded from further analysis. That is, only particles having a maximum diameter in the range of 0.9 times or more and less than 1.1 times the primary particle diameter were subjected to the following analysis. Next, on the particle surfaces on both sides, read the niobium atomic concentration (atomic %) within 5% of the maximum diameter of the measured particle from the particle surface, calculate the arithmetic mean value of the two values obtained, Niobium atomic concentration (atomic %) within 5% of the maximum diameter of the measured particles from the surface is obtained. Similarly, the "titanium atom concentration (atomic %) within 5% of the maximum diameter of the measured particle from the particle surface" is obtained. Then, using these values, the "concentration ratio of niobium atoms and titanium atoms within 5% of the maximum diameter of the measured grain from the grain surface" on the grain surfaces on both sides is obtained from the following formula.
(Concentration ratio of niobium atoms and titanium atoms within 5% of the maximum diameter of the measured particle from the particle surface) =
(Niobium atomic concentration (atomic %) within 5% of the maximum diameter of the measured particle from the particle surface) / (Titanium atomic concentration (atomic %) within 5% of the maximum diameter of the measured particle from the particle surface)
Of the two concentration ratios obtained, the smaller one is adopted as the "concentration ratio of niobium atoms and titanium atoms within 5% of the maximum diameter of the measured particles from the particle surface" in the present invention. It should be noted that there is no significant difference between the two concentration ratios in ordinary particles.
Further, the niobium atomic concentration (atomic %) and the titanium atomic concentration (atomic %) at the midpoint of the maximum diameter on the straight line are read. Using these values, the "concentration ratio of niobium atoms and titanium atoms in the grain center" is obtained from the following formula.
Concentration ratio of niobium atoms and titanium atoms in the grain center =
(Niobium atomic concentration in the center of the grain (atomic %)) / (Titanium atomic concentration in the central part of the grain (atomic %))
In addition, "concentration ratio calculated by niobium atomic concentration/titanium atomic concentration in 5% of the maximum diameter of the measured particle from the particle surface to the concentration ratio calculated by niobium atomic concentration/titanium atomic concentration in the center of the particle ” is calculated by the following formula.
(Concentration ratio calculated by niobium atomic concentration/titanium atomic concentration in 5% of the maximum diameter of the measured particle from the particle surface to the concentration ratio calculated by niobium atomic concentration/titanium atomic concentration in the center of the particle) =
(concentration ratio of niobium atoms and titanium atoms within 5% of the maximum diameter of the measured particle from the particle surface)/(concentration ratio of niobium atoms and titanium atoms at the center of the particle)

<Calculation of content of conductive particles>
Next, four sample pieces of 5 mm square were cut out from the photoreceptor, and the protective layer was three-dimensionalized to 2 μm×2 μm×2 μm by Slice & View of FIB-SEM. From the difference in FIB-SEM Slice & View contrast, the content of the conductive particles in the total area of the protective layer was calculated. The conditions for Slice & View were as follows.
Sample processing for analysis: FIB method Processing and observation device: NVision 40 manufactured by SII/Zeiss
Slice interval: 10 nm
Observation conditions:
Accelerating voltage: 1.0 kV
Sample tilt: 54°
WD: 5mm
Detector: BSE detector Aperture: 60 μm, high current
ABC: ON
Image resolution: 1.25 nm/pixel
The analysis area is 2 μm long×2 μm wide, and the information for each section is integrated to obtain the volume V per 2 μm long×2 μm wide×2 μm thick (8 μm ³ ). The measurement environment is temperature: 23° C., pressure: 1×10 ⁻⁴ Pa. As a processing and observation device, Strata 400S manufactured by FEI (specimen tilt: 52°) can also be used. Information on each cross section was obtained by image analysis of the area of the specified conductive particles of the present invention. Image analysis was performed using image processing software: Image-Pro Plus manufactured by Media Cybernetics.
Based on the obtained information, in each of the four sample pieces, the volume V of the conductive particles of the present invention in a volume of 2 μm × 2 μm × 2 μm (unit volume: 8 μm ³ ) was determined, and the content of the conductive particles [Volume %] (=Vμm ³ /8 μm ³ ×100) was calculated. The average value of the content values of the conductive particles in the four sample pieces was taken as the content [% by volume] of the conductive particles of the present invention in the protective layer relative to the total volume of the protective layer.
At this time, for all four sample pieces, the film thickness t (cm) of the protective layer was measured by processing up to the boundary between the protective layer and the lower layer, and the following <Method for measuring volume resistivity of protective layer> The film thickness of the protective layer was used to calculate the volume resistivity ρ _v .

<Quantification of Niobium Atoms Contained in Conductive Particles>
The quantification of niobium atoms contained in the conductive particles is performed as follows.
The conductive particles recovered from the photoreceptor in <calculation of primary particle size of conductive particles> are pelletized by the following press molding to prepare a sample. Using the prepared sample, measurement is performed with an X-ray fluorescence spectrometer (XRF), and the niobium atom content of the entire conductive particles is quantified by the FP method.
Specifically, niobium pentoxide is quantified and converted to the niobium atom content.
(i) Examples of devices used X-ray fluorescence analyzer 3080 (Rigaku Denki Co., Ltd.)
(ii) Sample Preparation A sample press molding machine, MAEKAWA Testing Machine (manufactured by MFG Co, Ltd.), is used for sample preparation. 0.5 g of conductive particles are placed in an aluminum ring (model number: 3481E1), set to a load of 5.0 tons, and pressed for 1 minute to pelletize.
(iii) Measurement conditions Measurement diameter: 10φ
Measurement potential, voltage 50 kV, 50 to 70 mA
2θ angle 25.12°
Crystal plate LiF
Measurement time 60 seconds

<Powder X-ray diffraction measurement of conductive particles>
A method for determining whether the conductive particles used in the electrophotographic photoreceptor of the present invention contain anatase-type titanium oxide or rutile-type titanium oxide will be described below.
From the chart obtained from powder X-ray diffraction by X-rays of CuKα, identification is performed with the inorganic material database (AtomWork) of the National Institute for Materials Science (NIMS). For the conductive particles contained in the protective layer of the electrophotographic photosensitive member of the present invention, the treatment described above (quantification of Nb atoms contained in the conductive particles) is applied as an example.
Measuring instrument used: Rigaku Denki Co., Ltd., X-ray diffractometer RINT-TTRII
X-ray tube: Cu
Tube voltage: 50KV
Tube current: 300mA
Scanning method: 2θ/θ scan Scanning speed: 4.0°/min
Sampling interval: 0.02°
Start angle (2θ): 5.0°
Stop angle (2θ): 40.0°
Attachment: Standard Sample Holder Filter: Not Used Incident Monochrome: Used Counter Monochromator: Not Used Divergence Slit: Open Divergence Longitudinal Limiting Slit: 10.00 mm
Scattering slit: Open Receiving slit: Open flat plate Monochromator: Counter used: Scintillation counter

<Method for measuring volume resistivity of protective layer>
A pA (picoampere) meter was used to measure the volume resistivity of the present invention.
First, the inter-electrode distance (D) of 180 μm and the length (L) of 59 mm are formed on a PET film by vapor deposition, and a protective layer having a thickness (T1) of 2 μm is provided thereon. . Next, under the environment of temperature 23° C./humidity 50% RH and temperature 32.5° C./humidity 80% RH, direct current (I) when a direct voltage (V) of 100 V is applied between the comb electrodes. was measured, and the volume resistivity ρ _v (Ω·cm) was obtained by the following formula (1).
Volume resistivity ρ _v (Ω cm) = V (V) × T1 (cm) × L (cm) / {I (A) × D (cm)} (1)

If it is difficult to identify the composition of the conductive particles and binder resin of the protective layer, the surface resistivity is measured on the surface of the electrophotographic photosensitive member and converted into volume resistivity. When measuring the volume resistivity of the protective layer applied to the surface of the photoreceptor instead of the protective layer alone, it is advisable to measure the surface resistivity of the protective layer and convert it to volume resistivity. desirable.
In the present invention, the inter-electrode distance (D) of 180 μm and the length (L) of 59 mm shown in FIG. Next, in an environment of temperature 23° C./humidity 50% RH, a direct current (I) was measured when a direct voltage (V) of 1000 V was applied between the comb-shaped electrodes. The surface resistivity ρ _s of the protective layer was calculated from the direct current (I).
Furthermore, using the film thickness t (cm) of the protective layer measured in <Calculation of Content of Conductive Particles> described above, the volume resistivity ρ _v (Ω·cm) was calculated by the following formula (2).
_ρv = _ρs × t (2)
(ρ _v : volume resistivity, ρ _s : surface resistivity, t: thickness of protective layer)
In this measurement, since a very small amount of current is measured, it is preferable to use a device capable of measuring a very small current as the resistance measuring device. For example, picoammeter 4140B manufactured by Hewlett-Packard and the like can be used. It is desirable to select the comb-shaped electrode to be used and the voltage to be applied so that an appropriate SN ratio can be obtained depending on the material and resistance value of the charge injection layer.

<Measurement of Content of Polyvalent Metal Element in Toner Particles (ICP-AES)>
(1) Method of Obtaining Toner Particles by Washing External Additive Particles from Toner When the toner contains an external additive such as silica fine particles, the external additive is removed from the toner particle surface through the following steps.
5 g of toner is weighed into a 200 ml plastic cup with a lid using a precision balance, 100 ml of methanol is added, and dispersed for 5 minutes with an ultrasonic disperser. After confirming that the toner has sufficiently precipitated using a centrifuge, the supernatant liquid is discarded. After repeating the operation of dispersing with methanol and discarding the supernatant three times, 100 ml of 10% NaOH was added to "Contaminon N" (a nonionic surfactant, anionic surfactant, and an organic builder to clean the pH 7 precision measuring instrument). A few drops of a 10% by mass aqueous solution of a neutral detergent for liquid cleaners (manufactured by Wako Pure Chemical Industries, Ltd.) are added, lightly mixed, and allowed to stand for 24 hours. After that, they are separated using a centrifuge. In addition, at this time, rinsing with distilled water is repeated so that NaOH does not remain. The collected toner particles are sufficiently dried in a vacuum dryer to obtain toner particles. By the above operation, the external additive of the silica fine particles is dissolved and removed.

(2) Measurement of Content of Polyvalent Metal Element in Toner Particles The content of polyvalent metal elements in the toner particles is quantified using an induced coupled plasma atomic emission spectrometer (ICP-AES (manufactured by Seiko Instruments Inc.)). do.
As a pretreatment, 100.0 mg of toner particles are subjected to acid decomposition using 8.00 ml of 60% nitric acid (manufactured by Kanto Kagaku, for atomic absorption spectrometry).
At the time of acid decomposition, treatment is performed in a sealed vessel at an internal temperature of 220°C for 1 hour using a microwave high-power sample pretreatment device ETHOS1600 (manufactured by Milestone General Co., Ltd.) to prepare a polyvalent metal element-containing solution sample. .
After that, add ultrapure water so that the total amount becomes 50.00 g to obtain a measurement sample. A calibration curve is prepared for each polyvalent metal element, and the amount of metal contained in each sample is quantified. In addition, ultrapure water was added to 8.00 ml of nitric acid to make a total of 50.00 g, which was measured as a blank, and the amount of metal in the blank was subtracted.

<Identification of Wax in Toner>
(1) Method of Separating Wax from Toner Although the wax in the toner can be measured even if the toner is intact, it is more preferable to perform a separation operation.
First, the melting point of the wax in the toner is measured using a thermal analyzer (DSC Q2000, manufactured by TA Instruments Japan Co., Ltd.). About 3.0 mg of a toner sample is placed in a sample container of an aluminum pan (KIT No. 0219-0041), the sample container is placed on a holder unit, and set in an electric furnace. The toner sample is heated from 30° C. to 200° C. at a heating rate of 10° C./min in a nitrogen atmosphere, the DSC curve is measured by a differential scanning calorimeter (DSC), and the melting point of the wax in the toner sample is calculated.
Next, the toner is dispersed in ethanol, which is a poor solvent for the toner, and heated to a temperature exceeding the melting point of wax. At this time, pressurization may be applied if necessary. By this operation, the wax that has exceeded its melting point is melted and extracted into ethanol. The wax can be separated from the toner by performing solid-liquid separation while heating and further pressurizing. Next, the wax is obtained by drying and solidifying the extract.

(2) Identification of Wax by Pyrolysis GCMS Specific conditions for wax identification by pyrolysis GCMS are shown below.
Mass spectrometer: ThermoFisherScinetific ISQ
GC device: ThermoFisherScinetific FocusGC
Ion source temperature: 250°C
Ionization method: EI
Mass Range: 50-1000m/z
Column: HP-5MS [30m]
Pyrolyzer: JPS-700 manufactured by Japan Analytical Industry Co., Ltd.
A small amount of the wax separated by the extraction procedure and 1 μL of tetramethylammonium hydroxide (TMAH) are added to the pyrofoil at 590°C. The prepared sample is subjected to pyrolysis GCMS measurement under the above conditions to obtain a wax-derived peak. When the wax is an ester compound, peaks are obtained for each of the alcohol component and the carboxylic acid component. An alcohol component and a carboxylic acid component are detected as methylated products by the action of TMAH, which is a methylating agent. The molecular weight can also be obtained by analyzing the obtained peaks and identifying the structure of the ester compound.

<Method for Measuring Weight Average Particle Diameter (D4) of Toner>
The weight average particle size (D4) of the toner is calculated as follows.
As a measurement device, a precision particle size distribution measurement device "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with a 100 μm aperture tube is used.
The attached dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.) is used for setting the measurement conditions and analyzing the measurement data. The measurement is performed with 25,000 effective measurement channels.
The electrolytic aqueous solution used for the measurement can be prepared by dissolving special grade sodium chloride in ion-exchanged water so that the concentration becomes 1.0%, for example, "ISOTON II" (manufactured by Beckman Coulter, Inc.) can be used. .

Before performing measurement and analysis, set the dedicated software as follows.
On the "Change standard measurement method (SOMME)" screen of the dedicated software, set the total number of counts in control mode to 50,000 particles, set the number of measurements to 1, and set the Kd value to "standard particle 10.0 μm" (Beckman Coulter, Inc.) is used to set the value obtained. By pressing the "threshold/noise level measurement button", the threshold and noise level are automatically set. Also, set the current to 1,600 μA, the gain to 2, the electrolyte to ISOTON II, and put a check in the “Flush aperture tube after measurement” box.
On the "pulse-to-particle size conversion setting" screen of the dedicated software, set the bin interval to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range from 2 μm to 60 μm.

A specific measuring method is as follows.
(1) Put 200.0 mL of an electrolytic aqueous solution into a 250 mL glass round-bottomed beaker dedicated to Multisizer 3, set it on a sample stand, and stir the stirrer rod counterclockwise at 24 revolutions/second. Then, remove the dirt and air bubbles inside the aperture tube using the dedicated software's "Flush Aperture Tube" function.
(2) Put 30.0 mL of the electrolytic aqueous solution into a 100 mL flat-bottom glass beaker. As a dispersant, "Contaminon N" (a 10% aqueous solution of a neutral detergent for cleaning precision measuring instruments at pH 7 consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) was used as a dispersant. ) is diluted with ion-exchanged water to 3 times the mass, and 0.3 mL of the diluted solution is added.
(3) Prepare an ultrasonic disperser "Ultrasonic Dispersion System Tetra 150" (manufactured by Nikkaki Bios Co., Ltd.) with an electrical output of 120 W and two oscillators with an oscillation frequency of 50 kHz built in with a phase shift of 180 degrees. do. 3.3 L of deionized water is placed in the water tank of the ultrasonic disperser, and 2.0 mL of Contaminon N is added to this water tank.
(4) The beaker of (2) above is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. Then, the height position of the beaker is adjusted so that the resonance state of the liquid level of the electrolytic aqueous solution in the beaker is maximized.
(5) While the electrolytic aqueous solution in the beaker in (4) above is being irradiated with ultrasonic waves, 10 mg of toner or the like is added little by little to the electrolytic aqueous solution and dispersed. Then, the ultrasonic dispersion treatment is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water in the water tank is appropriately adjusted to 10°C or higher and 40°C or lower.
(6) Using a pipette, drip the electrolytic aqueous solution of (5) in which toner is dispersed into the round-bottomed beaker of (1) set up in the sample stand, and adjust the measured concentration to 5%. . The measurement is continued until the number of measured particles reaches 50,000.
(7) Analyze the measurement data with dedicated software attached to the apparatus to calculate the weight average particle diameter (D4). The weight average particle diameter (D4) is the "average diameter" on the "analysis/volume statistics (arithmetic mean)" screen when graph/vol% is set using dedicated software.

(Example)
Hereinafter, the photoreceptor and toner according to the present invention will be described in detail using examples and comparative examples. In the description of the following examples, "parts" are based on mass unless otherwise specified.

An example of manufacturing a photoreceptor will be described below.
<Production Examples of Titanium Oxide Particles 1 to 3>
The titanium oxide particles contained in the surface protective layer of the present invention preferably have a degree of anatase of 90 to 100%, and titanium oxide particles having a degree of anatase of approximately 100% can be produced by the following method.
Here, the degree of anatase is obtained by measuring the intensity IA of the strongest interference line of anatase (plane index 101) and the intensity IR of the strongest interference line of rutile (plane index 110) in powder X-ray diffraction of titanium oxide particles, It is a value calculated by the following formula.
Degree of anatase (%) = 100/(1 + 1.265 x IR/IA)
In the present invention, a solution containing titanyl sulfate was heated and hydrolyzed to prepare a hydrous titanium dioxide slurry, which was dehydrated and calcined to obtain anatase-type titanium oxide particles. By controlling the titanyl sulfate solution concentration, the number average particle size of the anatase type titanium oxide particles is controlled, and titanium oxide particles 1 having a number average particle size of 150 nm, titanium oxide particles 2 having a number average particle size of 160 nm, and number average Titanium oxide particles 3 having a particle size of 130 nm were obtained.

<Production Example of Niobium Atom-Containing Titanium Oxide Particles 1>
100 g of titanium oxide particles 1 were dispersed in water and heated to 60° C. to form a 1 L aqueous suspension. This was mixed with a niobium solution obtained by dissolving 3 g of niobium pentachloride (NbCl ₅ ) in 100 mL of 11.4 mol/L hydrochloric acid and 600 mL of a titanium sulfate solution containing 33.7 g of titanium as titanium niobate solution (niobium in the solution and Mass ratio of titanium is 1.0/33.7) and 10.7 mol/L sodium hydroxide aqueous solution are added dropwise over 3 hours at the same time so that the pH of the suspension becomes 2 to 3 (parallel addition )bottom. After completion of dropping, the suspension was filtered, washed and dried at 110° C. for 8 hours. The dried product was subjected to heat treatment (calcination treatment) at 800° C. for 1 hour in an air atmosphere to obtain niobium atom-containing titanium oxide particles 1 in which niobium atoms were unevenly distributed near the surface. Table 1 shows the physical properties of the niobium atom-containing titanium oxide particles 1.

<Production Example of Niobium Atom-Containing Titanium Oxide Particles 2>
Niobium atom-containing titanium oxide particles 2 were obtained in the same manner as in the production of niobium atom-containing titanium oxide particles 1 except that titanium oxide particles 1 were changed to titanium oxide particles 2 and the coating conditions were appropriately changed. Table 1 shows the physical properties of the niobium atom-containing titanium oxide particles 2.

<Production Example of Niobium Atom-Containing Titanium Oxide Particles 3>
Niobium sulfate (a water-soluble niobium compound) was added to a hydrous titanium dioxide slurry obtained by hydrolyzing an aqueous titanyl sulfate solution. Niobium sulfate was added at a rate of 0.20% by mass as niobium ions with respect to the amount of titanium in the slurry (converted to titanium dioxide).
After hydrolyzing and dehydrating the above, it was fired at a firing temperature of 1000°C. As a result, anatase-type titanium oxide particles containing 0.20% by mass of niobium atoms and having a number average particle size of 150 nm (pre-coating niobium atom-containing titanium oxide particles) were obtained.
In the production of the niobium atom-containing titanium oxide particles 1, the niobium atom-containing titanium oxide particles 3 were produced in the same manner, except that the titanium oxide particles 1 were changed to the above-mentioned niobium atom-containing titanium oxide particles and the coating conditions were appropriately changed. Obtained. The obtained niobium atom-containing titanium oxide particles 3 were particles in which niobium atoms were also present inside the particles. Table 1 shows the physical properties of the niobium atom-containing titanium oxide particles 3.

<Production Examples of Niobium Atom-Containing Titanium Oxide Particles 4 to 9>
In the production of niobium atom-containing titanium oxide particles 3, production was carried out in the same manner, except that the titanyl sulfate aqueous solution was changed to change the number average particle diameter of the niobium atom-containing titanium oxide particles before coating, and that the conditions during coating were appropriately changed. , niobium atom-containing titanium oxide particles 4 to 9 were obtained. Table 1 shows the physical properties of niobium atom-containing titanium oxide particles 4 to 9.

<Production Example of Niobium Atom-Containing Titanium Oxide Particles 10>
In the production of niobium atom-containing titanium oxide particles 3, the amount of niobium ions was changed, and a niobium solution in which 3 g of niobium pentachloride (NbCl ₅ ) was dissolved in 100 mL of 11.4 mol/L hydrochloric acid was not used during coating. obtained niobium atom-containing titanium oxide particles 10 in the same manner. Table 1 shows physical properties of the niobium atom-containing titanium oxide particles 10 .

<Niobium atom-containing titanium oxide particles 11>
Niobium atom-containing titanium oxide particles 11 were obtained in the same manner as in the production of niobium atom-containing titanium oxide particles 3, except that the concentration of the titanyl sulfate aqueous solution and the amount of niobium ions were changed and the coating was not performed. Table 1 shows physical properties of the niobium atom-containing titanium oxide particles 11 .

これらを、トルエン２００．０部に混合し、攪拌装置で４時間攪拌した後、ろ過、洗浄後、さらに１３０℃で３時間加熱処理を行った。このようにして表面処理を行い、導電性粒子１を得た。導電性粒子１の物性を表２に示す。なお、表２中のニオブ原子含有量は、導電性粒子におけるニオブ原子の含有量であり、蛍光Ｘ線による元素分析法（ＸＲＦ）により測定して得た値である。 <Production example of conductive particles 1>
The following materials were prepared.
・ Niobium atom-containing titanium oxide particles 1 (specific gravity: 4 g / cm ³ ) 100.0 parts ・ A compound represented by the following formula (S-1) as a silane coupling agent (trade name: KBM-3033, Shin-Etsu Chemical Co., Ltd. ) made) 3.0 parts

These were mixed with 200.0 parts of toluene, stirred with a stirrer for 4 hours, filtered and washed, and then heat-treated at 130° C. for 3 hours. Conductive particles 1 were obtained by surface treatment in this way. Table 2 shows the physical properties of the conductive particles 1. The niobium atom content in Table 2 is the content of niobium atoms in the conductive particles, and is a value obtained by measurement by an elemental analysis method (XRF) using fluorescent X-rays.

表中、Ａは、「粒子表面から粒子の最大径の５％内部におけるニオブ原子とチタン原子との濃度比率」であり、Ｂは、「粒子中心部におけるニオブ原子とチタン原子との濃度比率」である。

In the table, A is "the concentration ratio of niobium atoms and titanium atoms within 5% of the maximum diameter of the particles from the particle surface", and B is "the concentration ratio of niobium atoms and titanium atoms in the center of the particles". is.

<Production Examples of Conductive Particles 2 to 6, 8 to 13>
In the production example of conductive particles 1, the niobium atom-containing titanium oxide particles used were changed as shown in Table 2, and the conditions during the surface treatment were changed as appropriate. Sexual particles 2-6 and 8-13 were obtained. Table 2 shows the physical properties of the conductive particles 2 to 6 and 8 to 13.

これらを、トルエン２００．０部に混合し、攪拌装置で４時間攪拌した後、ろ過、洗浄後、さらに１３０℃で３時間加熱処理を行った。このようにして、導電性粒子７を得た。導電性粒子７の物性を表２に示す。 <Production example of conductive particles 7>
The following materials were prepared.
・Tin oxide particles (trade name: S-2000, manufactured by Mitsubishi Materials Corporation, number average particle diameter 100 nm) 100.0 parts ・20.0 parts of the compound represented by the formula (S-2)

These were mixed with 200.0 parts of toluene, stirred with a stirrer for 4 hours, filtered and washed, and then heat-treated at 130° C. for 3 hours. Thus, conductive particles 7 were obtained. Table 2 shows the physical properties of the conductive particles 7 .

<Production Example of Electrophotographic Photoreceptor 1>
An aluminum cylinder (JIS-A3003, aluminum alloy) having a diameter of 24 mm and a length of 257.5 mm was used as a support (conductive support).

(Manufacturing example of conductive layer)
Next, the following materials were prepared.
・214.0 parts of titanium oxide (TiO ₂ ) particles (number average particle diameter 230 nm) coated with oxygen-deficient tin oxide (SnO ₂ ) as metal oxide particles ・Phenol resin (phenol resin monomer/oligomer) (trade name: Plyophen J-325, manufactured by DIC Corporation, resin solid content: 60% by mass) 132.0 parts 1-methoxy-2-propanol as a solvent 98.0 parts , Put it in a sand mill using 450.0 parts of glass beads with a diameter of 0.8 mm, and perform dispersion treatment under the conditions of rotation speed: 2000 rpm, dispersion treatment time: 4.5 hours, cooling water set temperature: 18 ° C., and dispersed. I got the liquid. The glass beads were removed from this dispersion with a mesh (opening: 150 μm).
Silicone resin particles (trade name: Tospearl 120, Momentive Performance Materials Co., Ltd., average particle size: 2 μm) were added to the resulting dispersion as a surface roughening agent. The amount of the silicone resin particles added was adjusted to 10% by mass with respect to the total mass of the metal oxide particles and the binder material in the dispersion after removing the glass beads. In addition, silicone oil (trade name: SH28PA, manufactured by Dow Corning Toray Co., Ltd.) was added as a leveling agent to 0.01% by mass with respect to the total mass of the metal oxide particles and the binder in the dispersion. ) was added to the dispersion.
Next, methanol and A mixed solvent of 1-methoxy-2-propanol (mass ratio 1:1) was added to the dispersion. After that, the mixture was stirred to prepare a conductive layer coating liquid.
This conductive layer coating solution was applied onto a support by dip coating and heated at 140° C. for 1 hour to form a conductive layer having a thickness of 30 μm.

(Manufacturing example of undercoat layer)
Next, the following materials were prepared.
3.1 parts of an electron-transporting substance represented by the following formula (E-1) Block isocyanate (trade name: Duranate SBB-70P, manufactured by Asahi Kasei Chemicals Co., Ltd.) 6.5 parts Styrene-acrylic resin (trade name: UC-3920, manufactured by Toagosei) 0.40 parts Silica slurry (product name: IPA-ST-UP, manufactured by Nissan Chemical Industries, solid content concentration: 15% by mass, viscosity: 9 mPa s) 1.8 parts of these , 48.0 parts of 1-butanol and 24.0 parts of acetone in a mixed solvent to prepare an undercoat layer coating solution. This undercoat layer coating solution was dip-coated on the conductive layer and heated at 170° C. for 30 minutes to form an undercoat layer having a thickness of 0.7 μm.

(Production example of photosensitive layer)
Next, in a chart obtained by CuKα characteristic X-ray diffraction, 10.0 parts of crystalline hydroxygallium phthalocyanine having peaks at positions of 7.5° and 28.4° and polyvinyl butyral resin (trade name: S-LEC BX- 1, manufactured by Sekisui Chemical Co., Ltd.) was prepared.
These were added to 200.0 parts of cyclohexanone and dispersed for 6 hours with a sand mill apparatus using glass beads with a diameter of 0.9 mm. 150.0 parts of cyclohexanone and 350.0 parts of ethyl acetate were further added to dilute the mixture to obtain a coating solution for a charge generation layer.
The obtained coating solution was dip-coated on the undercoat layer and dried at 95° C. for 10 minutes to form a charge generation layer having a thickness of 0.20 μm.

The X-ray diffraction measurement was performed under the following conditions.
[Powder X-ray diffraction measurement]
Measuring instrument used: Rigaku Denki Co., Ltd., X-ray diffractometer RINT-TTRII
X-ray tube: Cu
Tube voltage: 50KV
Tube current: 300mA
Scanning method: 2θ/θ scan Scanning speed: 4.0°/min
Sampling interval: 0.02°
Start angle (2θ): 5.0°
Stop angle (2θ): 40.0°
Attachment: Standard Sample Holder Filter: Not Used Incident Monochrome: Used Counter Monochromator: Not Used Divergence Slit: Open Divergence Longitudinal Limiting Slit: 10.00 mm
Scattering slit: Open Receiving slit: Open flat plate Monochromator: Counter used: Scintillation counter

Next, the following materials were prepared.
・6.0 parts of a charge-transporting substance (hole-transporting substance) represented by the following formula (C-1) ・3.0 parts of a charge-transporting substance (hole-transporting substance) represented by the following formula (C-2)・Charge-transporting substance (hole-transporting substance) represented by the following formula (C-3): 1.0 parts ・Polycarbonate (trade name: Iupilon Z400, manufactured by Mitsubishi Engineering-Plastics Co., Ltd.): 10.0 parts ・Formula below: 0.02 parts of a polycarbonate resin (x/y=0.95/0.05: viscosity average molecular weight=20000) having a copolymer unit of (C-4) and the following formula (C-5) A charge transport layer coating solution was prepared by dissolving in a mixed solvent of .0 part/25.0 parts of methyl benzoate/25.0 parts of dimethoxymethane. The charge transport layer coating liquid was dip-coated on the charge generation layer to form a coating film, and the coating film was dried at 120° C. for 30 minutes to form a charge transport layer having a thickness of 12 μm.

・導電性粒子として導電性粒子１：４．０部
これらを、１－プロパノール５．０部／シクロヘキサン５．０部の混合溶媒に混合し、攪拌装置で６時間攪拌した。このようにして、保護層用塗布液を調製した。
この保護層用塗布液を電荷輸送層上に浸漬塗布して塗膜を形成し、得られた塗膜を６分間５０℃で乾燥させた。その後、窒素雰囲気下にて、加速電圧７０ｋＶ、ビーム電流５．０ｍＡの条件で支持体（被照射体）を３００ｒｐｍの速度で回転させながら、１．６秒間電子線を塗膜に照射した。保護層位置の線量は１５ｋＧｙであった。
その後、窒素雰囲気下にて、塗膜の温度を１１７℃に昇温させた。電子線照射から、その後の加熱処理までの酸素濃度は１０ｐｐｍであった。
次に、大気中において塗膜の温度が２５℃になるまで自然冷却した後、塗膜の温度が１２０℃になる条件で１時間加熱処理を行い、膜厚２μｍの表面保護層を形成した。
このようにして、電子写真感光体１を製造した。電子写真感光体の１の物性を表３に示す。 (Production example of surface protective layer)
Next, the following materials were prepared.
- A compound represented by the following structural formula (O-1) as a binder resin: 1.0 parts

Conductive particles as conductive particles: 1: 4.0 parts These were mixed in a mixed solvent of 5.0 parts of 1-propanol/5.0 parts of cyclohexane, and stirred for 6 hours with a stirring device. Thus, a protective layer coating liquid was prepared.
This protective layer coating liquid was applied onto the charge transport layer by dip coating to form a coating film, and the resulting coating film was dried at 50° C. for 6 minutes. After that, in a nitrogen atmosphere, the coating film was irradiated with an electron beam for 1.6 seconds while rotating the support (object to be irradiated) at a speed of 300 rpm under the conditions of an acceleration voltage of 70 kV and a beam current of 5.0 mA. The dose at the protective layer was 15 kGy.
After that, the temperature of the coating film was raised to 117° C. in a nitrogen atmosphere. The oxygen concentration from the electron beam irradiation to the subsequent heat treatment was 10 ppm.
Next, after naturally cooling in the air until the temperature of the coating film reached 25° C., heat treatment was performed for 1 hour under the condition that the temperature of the coating film reached 120° C. to form a surface protective layer having a thickness of 2 μm.
Thus, the electrophotographic photoreceptor 1 was manufactured. Table 3 shows the physical properties of electrophotographic photoreceptor 1.

<Production Examples of Electrophotographic Photoreceptors 2 to 6, 8 to 13, 15, and 16>
In the production example of electrophotographic photoreceptor 1, the type and content (% by volume) of the conductive particles used in (production example of surface protective layer) were changed as shown in Table 3, electrophotographic photoreceptor 1 Electrophotographic photosensitive members 2 to 6, 8 to 13, 15 and 16 were produced in the same manner as in Production Example 1. Table 3 shows the physical properties of the electrophotographic photoreceptors 2 to 6, 8 to 13, 15 and 16.

<Manufacturing Example of Electrophotographic Photoreceptor 7>
Electrophotographic photoreceptor 7 was obtained in the same manner as in Production example of electrophotographic photoreceptor 1, except that (Example of production of surface protective layer) was changed as follows.
A coating liquid for a surface protective layer was prepared as follows.
First, the following materials were prepared.
Conductive particles 5: 16.0 parts 10.0 parts of a compound represented by the following formula (H-7) Polymerization initiator (1-hydroxycyclohexyl (phenyl) methanone) 1.0 parts The mixture was mixed with 40 parts of alcohol and dispersed for 2 hours using a sand mill to prepare a protective layer coating liquid.
Electrophotographic photoreceptor 7 was produced in the same manner as electrophotographic photoreceptor 1 except that this protective layer coating liquid was used. Table 3 shows the physical properties of the electrophotographic photoreceptor 7.

<Manufacturing Example of Electrophotographic Photoreceptor 14>
In the production example of the electrophotographic photoreceptor 7, in the same manner as in the production example of the electrophotographic photoreceptor 7, except that the addition amount of the conductive particles 5 in (Production example of the surface protective layer) was changed to 10.0 parts by mass, An electrophotographic photoreceptor 14 was obtained. Table 3 shows the physical properties of the electrophotographic photoreceptor 14 .

これらをテトラヒドロフラン１００．０部に混合し、攪拌装置で６時間攪拌し、これにより保護層用塗布液を調製した。
この保護層用塗布液を窒素気流中でスプレー塗工法により電荷輸送層上に塗布して塗膜を形成し、１０分間窒素気流中に放置して、乾燥した。その後、酸素濃度が２％以下となるようにブース内を窒素ガスで置換した紫外線光照射ブースにて、紫外線照射を以下の条件で行った。
メタルハライドランプ：１６０Ｗ／ｃｍ
照射距離：１２０ｍｍ
照射強度：７００ｍＷ／ｃｍ^２
照射時間：６０秒
さらに、１３０℃で２０分間乾燥することで、膜厚が５μｍの表面保護層を形成した。
このようにして、電子写真感光体１７を得た。電子写真感光体１７の物性を表３に示す。 <Manufacturing Example of Electrophotographic Photoreceptor 17>
An electrophotographic photoreceptor 17 was obtained in the same manner as in the production example of the electrophotographic photoreceptor 1 except that the (surface protective layer production example) was changed as follows.
A coating liquid for a surface protective layer was prepared as follows.
First, the following materials were prepared.
10.0 parts of a radically polymerizable monomer (product name: TMPTA, manufactured by Tokyo Kasei Co., Ltd.) 5 parts of a compound represented by the following formula (H-1) 0.0 parts of a compound represented by the following formula (H-2) 15 parts · 0.15 parts of the compound represented by the following formula (H-3) · Fluoropolymer particles (product name: MPE-056, manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) 1.5 parts · Photopolymerization initiator ( Product name: Irgacure 184, manufactured by BASF Japan Ltd.) 0.75 parts

These were mixed with 100.0 parts of tetrahydrofuran and stirred with a stirrer for 6 hours to prepare a protective layer coating solution.
This protective layer coating solution was applied onto the charge transport layer by a spray coating method in a nitrogen stream to form a coating film, which was allowed to stand in a nitrogen stream for 10 minutes to dry. Thereafter, ultraviolet irradiation was performed under the following conditions in an ultraviolet light irradiation booth in which the inside of the booth was replaced with nitrogen gas so that the oxygen concentration was 2% or less.
Metal halide lamp: 160W/cm
Irradiation distance: 120mm
Irradiation intensity: 700 mW/cm ²
Irradiation time: 60 seconds Further, by drying at 130°C for 20 minutes, a surface protective layer having a thickness of 5 µm was formed.
Thus, an electrophotographic photoreceptor 17 was obtained. Table 3 shows the physical properties of the electrophotographic photoreceptor 17.

Examples of toner production will be described below.
<Preparation Example of Binder Resin Particle Dispersion>
78.0 parts of styrene, 20.7 parts of butyl acrylate, 1.3 parts of acrylic acid as a carboxy group-imparting monomer, and 3.2 parts of n-lauryl mercaptan were mixed and dissolved. An aqueous solution of 1.5 parts of Neogen RK (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and 150.0 parts of ion-exchanged water was added to this solution and dispersed.
An aqueous solution of 0.3 parts of potassium persulfate and 10.0 parts of ion-exchanged water was added while slowly stirring for another 10 minutes. After purging with nitrogen, emulsion polymerization was carried out at 70° C. for 6 hours. After completion of the polymerization, the reaction solution was cooled to room temperature, and ion-exchanged water was added to obtain a resin particle dispersion 1 having a solid content concentration of 12.5% by mass and a volume-based median diameter of 0.2 μm.
In order to measure the acid value, part of the obtained resin particles was washed with pure water to remove the surfactant and dried under reduced pressure. As a result of measuring the acid value of the resin, it was confirmed to be 9.5 mgKOH/g.

<Preparation Example of Release Agent Dispersion 1>
100.0 parts of behenyl behenate (melting point: 72.1° C.) and 15.0 parts of Neogen RK were mixed with 385.0 parts of ion-exchanged water, and the mixture was mixed for about 1 hour using a wet jet mill JN100 (manufactured by Joko Co., Ltd.). A release agent dispersion liquid 1 was obtained by dispersion. The wax concentration of Release Agent Dispersion 1 was 20.0% by mass.

<Preparation Example of Release Agent Dispersion 2>
100.0 parts of pentaerythritol tetrabehenate (melting point: 84.2° C.) and 15 parts of Neogen RK were mixed with 385.0 parts of ion-exchanged water, and the wet jet mill JN100 (manufactured by Joko Co., Ltd.) was used to mix about 1 part. A release agent dispersion liquid 2 was obtained by time dispersion. The wax concentration of the release agent dispersion liquid 2 was 20.0% by mass.

<Preparation Example of Release Agent Dispersion 3>
Hydrocarbon wax HNP-9 (manufactured by Nippon Seiro Co., Ltd., melting point: 75.5 ° C.) 100.0 parts, Neogen RK 15 parts were mixed with ion-exchanged water 385.0 parts, and wet jet mill JN100 (Joko Co., Ltd.) (manufactured) for about 1 hour to obtain a release agent dispersion 3. The wax concentration of Release Agent Dispersion 3 was 20.0% by mass.

<Preparation Example of Colorant Dispersion>
100.0 parts of carbon black "Nipex 35 (manufactured by Orion Engineered Carbons)" as a coloring agent and 15 parts of Neogen RK are mixed with 885.0 parts of deionized water, and dispersed for about 1 hour using a wet jet mill JN100. A colorant dispersion was obtained.

<Production example of silica particles 1>
Untreated dry silica having a number average primary particle size of 18 nm was put into a reactor equipped with a stirrer and heated to 200° C. in a fluidized state by stirring.
The inside of the reactor was replaced with nitrogen gas, the reactor was sealed, and 25.0% by mass of dimethylsilicone oil (viscosity = 100 mm ² /sec) was sprayed on 100.0% by mass of dry silica, followed by stirring for 30 minutes. continued. After that, the temperature was raised to 300° C. while stirring, and after further stirring for 2 hours, the mixture was taken out and crushed to obtain silica particles 1 . The degree of hydrophobicity of silica particles 1 was 94.0%.

<Manufacturing Example of Toner 1>
265.0 parts of the resin particle dispersion, 10.0 parts of the release agent dispersion and 10.0 parts of the colorant dispersion were dispersed using a homogenizer (manufactured by IKA: Ultra Turrax T50). The temperature in the container was adjusted to 30° C. while stirring, and a 1 mol/L sodium hydroxide aqueous solution was added to adjust the pH to 8.0.
As a flocculating agent, an aqueous solution prepared by dissolving 0.25 parts of aluminum chloride in 10.0 parts of ion-exchanged water was added over 10 minutes while stirring at 30°C. After standing for 3 minutes, the temperature was started to rise up to 50° C., and associated particles were generated. In this state, the particle size of the associated particles is measured using "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.). When the weight average particle size reached 6.0 μm, 0.90 parts of sodium chloride and 5.0 parts of Neogen RK were added to stop the particle growth.
After adjusting the pH to 9.0 by adding a 1 mol/L sodium hydroxide aqueous solution, the temperature was raised to 95° C. to spheroidize the aggregated particles. When the average circularity reached 0.980, the temperature was lowered and cooled to room temperature to obtain a toner particle dispersion liquid 1.
Hydrochloric acid was added to the obtained toner particle dispersion liquid 1 to adjust the pH to 1.5 or less, and the mixture was allowed to stand with stirring for 1 hour, followed by solid-liquid separation using a pressure filter to obtain a toner cake. This was reslurried with ion-exchanged water to form a dispersion again, and then subjected to solid-liquid separation with the aforementioned filter. After reslurry and solid-liquid separation were repeated until the electrical conductivity of the filtrate became 5.0 μS/cm or less, solid-liquid separation was finally performed to obtain a toner cake. The obtained toner cake was dried and further classified using a classifier so that the weight-average particle diameter (D4) was 6.0 μm, whereby toner particles 1 were obtained.
To the toner particles 1 (100.0 parts) obtained above, silica particles 1 (1.0 parts) were externally added and mixed using FM10C (manufactured by Nippon Coke Kogyo Co., Ltd.). The external addition conditions were as follows: A0 blade was used as the lower blade, the distance from the wall of the deflector was set to 20 mm, the amount of toner particles charged: 2.0 kg, the rotation speed: 66.6 s ⁻¹ , the external addition time: 10 minutes, Cooling water was used at a temperature of 20° C. and a flow rate of 10 L/min.
Thereafter, the toner 1 was obtained by sieving with a mesh having an opening of 200 μm. Table 4 shows the physical properties of Toner 1 obtained.

<Production Example of Toner 2>
Toner 2 was obtained in the same manner as in Toner 1 except that release agent dispersion 2 was used. Table 4 shows the physical properties of Toner 2 obtained.

<Production Example of Toner 3>
Toner 3 was obtained in the same manner as in Toner 1 except that Release Agent Dispersion 3 was used. Table 4 shows the physical properties of Toner 3 obtained.

<Manufacturing Examples of Toners 4 to 6 and 15>
Toners 4 to 6 and 15 were obtained in the same manner as in Toner 1 Production Example, except that the number of parts of aluminum chloride added as a flocculant was changed as shown in Table 4. Table 4 shows physical properties of toners 4 to 6 and 15 obtained.

<Manufacturing Examples of Toners 7 to 9>
Toners 7 to 9 were obtained in the same manner as in Toner 1 Production Example, except that aluminum chloride added as a flocculant was changed to magnesium chloride and the number of parts added was changed as shown in Table 4. Table 4 shows the physical properties of toners 7 to 9 obtained.

<Manufacturing Examples of Toners 10 and 11>
Toners 10 and 11 were obtained in the same manner as in Toner 1 except that calcium chloride was used instead of aluminum chloride added as a flocculating agent, and the number of parts added was changed as shown in Table 4. Table 4 shows the physical properties of Toners 10 and 11 obtained.

<Manufacturing Examples of Toners 12 to 14 and 16>
Toners 12 to 14 and 16 were obtained in the same manner as in Toner 1 Production Example, except that the aluminum chloride added as a flocculant was changed to iron (III) chloride and the number of parts added was changed as shown in Table 4. rice field. Table 4 shows physical properties of toners 12 to 14 and 16 obtained.

<Example 1>
A commercially available color laser printer HP LaserJet Enterprise Color m553dn was partially modified for evaluation. As for the modification, the process speed of the main body was modified to 300 mm/sec, and necessary adjustments were made so that image formation could be performed under this condition.
Also, the toner was extracted from the black toner cartridge and refilled with 1:320 g of toner. Further, the photoreceptor was changed to the photoreceptor 1 of the present invention. The toner cartridge thus prepared was mounted in the black station, and dummy cartridges were mounted in the other stations, and the following image output test was carried out. Table 5 shows the results of evaluations 1 to 3 below.

(Evaluation 1 Evaluation of gradation under high-temperature and high-humidity environment)
Office 70 (manufactured by Canon Inc.) was set as a medium in the above printer, and 10,000 sheets of character pattern images with a print rate of 1% were passed at 30.0° C./80% RH. At this time, the paper was fed in a mode set so that two sheets/one job were set so that the next job would start after the machine stopped temporarily between jobs.
After passing through the paper, images of pattern 1 to pattern 8 having the image density gradation shown in FIG. determined by
In this evaluation, an image was output in a single black color. From the viewpoint of gradation reproducibility, the density range of each pattern image is preferably within the following range, and the evaluation was performed from this viewpoint.
Pattern 1: 0.10 or more and less than 0.15 Pattern 2: 0.15 or more and less than 0.20 Pattern 3: 0.20 or more and less than 0.30 Pattern 4: 0.25 or more and less than 0.40 Pattern 5: 0.55 0.70 or more Pattern 6: 0.65 or more and less than 0.80 Pattern 7: 0.75 or more and less than 0.90 Pattern 8: 1.40 or more
(Evaluation criteria)
A: All pattern images satisfy the above density range.
B: One pattern image deviates from the above density range.
C: Two pattern images deviate from the above density range.
D: Three or more pattern images deviate from the above density range.
E: Four or more pattern images are out of the above density range.
In this case, up to level D is certified as effective.

(Evaluation 2 Capri evaluation under high temperature and high humidity environment)
XEROX4200 paper (manufactured by XEROX 75g/m ² ) was set as media in the printer described above, and paper with a sticky note pasted on a part of the printing surface of the image at 30.0°C/80%RH for masking. was used to output an all-white image (white image 1). After that, 10,000 sheets of a character pattern image with a printing ratio of 1% were passed. At this time, the paper was fed in a mode set so that two sheets/one job were set so that the next job would start after the machine stopped temporarily between jobs. After passing 10,000 sheets, the printer was allowed to stand for 3 days, and then a paper with a sticky note pasted on a part of the printed surface of the image was used again to output an all-white image (white image 2). .
For the white image 1, after removing the sticky note, the reflectance (%) was measured at 5 points for the part with the sticky note and the part without the sticky note, and after calculating the average value, the average value was calculated. The difference was determined and defined as the initial fog.
Further, for the white image 2, the difference in the average values was obtained in the same manner, and this was used as the post-durability fog. The difference between the initial fogging and the fogging after the endurance test was determined, and the fogging after the endurance test was evaluated according to the following criteria.
The reflectance was measured using a digital white photometer (Type TC-6D, using a green filter manufactured by Tokyo Denshoku Co., Ltd.).
(Evaluation criteria)
A: Difference in fog between initial stage and after running test is less than 0.5% B: Difference in fog between initial stage and after running test is 0.5% or more and less than 1.5% C: Difference in fog between initial stage and after running test is 1.5% or more Less than 2.5% D: The fog difference between the initial stage and after the endurance test is 2.5% or more.

(Evaluation 3: Evaluation of fog under low-temperature and low-humidity environment)
Fog after continuous use under a low temperature and low humidity environment (15° C./10% RH) was evaluated. As the evaluation paper, XEROX4200 paper (75 g/m ² manufactured by XEROX) was used.
In a low-temperature and low-humidity environment, a sheet of paper with a sticky note attached as a mask was used to output an all-white image (white image 3). After that, 10,000 sheets of a character pattern image with a printing ratio of 1% were passed. At this time, the paper was fed in a mode set so that two sheets/one job were set so that the next job would start after the machine stopped temporarily between jobs. After that, a sheet of paper with a sticky note pasted on a part of the printed surface of the image was used as a mask to output an all-white image (white image 4).
For the white image 3, after removing the sticky note, the reflectance (%) was measured at 5 points for the part with the sticky note and the part without the sticky note, and the average value was calculated. The difference was determined and defined as the initial fog.
Further, for the white image 4, the difference between the average values was obtained in the same manner, and this was defined as the post-durability fog. The difference between the initial fogging and the fogging after the endurance test was determined, and the fogging after the endurance test was evaluated according to the following criteria.
The reflectance was measured using a digital white photometer (Type TC-6D, using a green filter manufactured by Tokyo Denshoku Co., Ltd.).
(Evaluation criteria)
A: Difference in fog between initial stage and after running test is less than 0.5% B: Difference in fog between initial stage and after running test is 0.5% or more and less than 1.5% C: Difference in fog between initial stage and after running test is 1.5% or more Less than 2.5% D: The fog difference between the initial stage and after the endurance test is 2.5% or more.

<Examples 2 to 26, Comparative Examples 1 to 6>
An image output test was performed in the same manner as in Example 1 except that the combination of the electrophotographic photosensitive member and the toner was changed as shown in Table 5, and evaluations 1 to 3 were performed. Each evaluation result is shown in Table 5.

The disclosure of this embodiment includes the following configurations.
(Configuration 1)
A process cartridge detachable from an electrophotographic apparatus main body,
The process cartridge is
an electrophotographic photoreceptor;
a developing means having a toner containing portion containing toner and supplying the toner to the surface of the electrophotographic photosensitive member;
has
The electrophotographic photoreceptor has a conductive support, and a photosensitive layer and a surface protective layer formed on the conductive support in this order,
The surface protective layer contains conductive particles,
The content of the conductive particles is 20.0% by volume or more and 70.0% by volume or less of the total volume of the surface protective layer,
The surface protective layer has a volume resistivity of 1.0×10 ⁹ Ω·cm or more and 1.0×10 ¹⁴ Ω·cm or less,
The toner contained in the toner container contains toner particles containing a binder resin and an external additive,
the toner particles have at least one polyvalent metal element selected from the group consisting of aluminum, magnesium, calcium and iron;
A process cartridge, wherein the total content of the polyvalent metal elements in the toner particles is 0.10 μmol/g or more and 1.25 μmol/g or less, as measured by coupled-inductive plasma-atomic emission spectrometry (ICP-AES). .
(Configuration 2)
Regarding the polyvalent metal element contained in the toner particles,
The aluminum content is 0.50 μmol/g or less,
The content of magnesium is 0.80 μmol / g or less,
the calcium content is 0.90 μmol/g or less,
The iron content is 1.25 μmol / g or less,
The total content of these polyvalent metal elements is 0.10 μmol/g or more and 1.25 μmol/g or less.
The process cartridge according to configuration 1.
(Composition 3)
The toner particles contain the aluminum at 0.10 μmol/g or more and 0.32 μmol/g or less as the polyvalent metal element.
A process cartridge according to configuration 1 or 2.
(Composition 4)
The process cartridge according to any one of Structures 1 to 3, wherein the toner particles contain wax, and the wax is an ester compound.
(Composition 5)
Structures 1 to 1, wherein a carboxy group is present in a molecular chain constituting the binder resin, and the carboxy group and the polyvalent metal element are present in the toner particles in a coordinated bond. 5. The process cartridge according to any one of 4.
(Composition 6)
The process cartridge according to any one of configurations 1 to 5, wherein the toner particles are emulsion aggregation toner particles.
(Composition 7)
7. The process cartridge according to any one of structures 1 to 6, wherein the conductive particles are titanium oxide particles.
(Composition 8)
A process cartridge according to configuration 7, wherein the titanium oxide particles are niobium atom-containing titanium oxide particles.
(Composition 9)
The niobium atom-containing titanium oxide particles have a concentration ratio calculated as niobium atom concentration/titanium atom concentration at the particle center, and the niobium atom concentration/titanium 8. The process cartridge according to Configuration 8, wherein the concentration ratio calculated by atomic concentration is 2.0 times or more.
(Configuration 10)
The process cartridge according to Structure 8 or 9, wherein the niobium atom-containing titanium oxide particles contain 2.6% by mass or more and 10.0% by mass or less of niobium atoms.
(Composition 11)
In the electrophotographic photoreceptor,
The content of the conductive particles is 40.0% by volume or more and 70.0% by volume or less of the surface protective layer,
11. The process cartridge according to any one of structures 1 to 10, wherein the surface protective layer has a volume resistivity of 1.0×10 ¹⁰ Ω·cm or more and 1.0×10 ¹⁴ Ω·cm or less.

REFERENCE SIGNS LIST 1 photoreceptor 2 shaft 3 charging means 4 exposure light 5 toner container and developing means 6 transfer means 7 transfer material 8 fixing means 9 cleaning means 10 pre-exposure light 11 process cartridge 12 guide means

Claims (11)

A process cartridge detachable from an electrophotographic apparatus main body,
The process cartridge is
an electrophotographic photoreceptor;
a developing means having a toner containing portion containing toner and supplying the toner to the surface of the electrophotographic photosensitive member;
has
The electrophotographic photoreceptor has a conductive support, and a photosensitive layer and a surface protective layer formed on the conductive support in this order,
The surface protective layer contains conductive particles,
The content of the conductive particles is 20.0% by volume or more and 70.0% by volume or less of the total volume of the surface protective layer,
The surface protective layer has a volume resistivity of 1.0×10 ⁹ Ω·cm or more and 1.0×10 ¹⁴ Ω·cm or less,
The toner contained in the toner container contains toner particles containing a binder resin and an external additive,
the toner particles have at least one polyvalent metal element selected from the group consisting of aluminum, magnesium, calcium and iron;
A process cartridge, wherein the total content of the polyvalent metal elements in the toner particles is 0.10 μmol/g or more and 1.25 μmol/g or less, as measured by coupled-inductive plasma-atomic emission spectrometry (ICP-AES). . Regarding the polyvalent metal element contained in the toner particles,
The aluminum content is 0.50 μmol/g or less,
The magnesium content is 0.80 μmol / g or less,
the calcium content is 0.90 μmol/g or less,
The iron content is 1.25 μmol / g or less,
The total content of these polyvalent metal elements is 0.10 μmol/g or more and 1.25 μmol/g or less.
2. A process cartridge according to claim 1. The toner particles contain the aluminum at 0.10 μmol/g or more and 0.32 μmol/g or less as the polyvalent metal element.
2. A process cartridge according to claim 1. 2. A process cartridge according to claim 1, wherein said toner particles contain wax, and said wax is an ester compound. 2. Carboxy groups are present in the molecular chains constituting the binder resin, and the carboxy groups and the polyvalent metal element are coordinately bonded in the toner particles. The process cartridge described in . 2. A process cartridge according to claim 1, wherein said toner particles are emulsion aggregation toner particles. 2. A process cartridge according to claim 1, wherein said conductive particles are titanium oxide particles. 8. A process cartridge according to claim 7, wherein said titanium oxide particles are niobium atom-containing titanium oxide particles. The niobium atom-containing titanium oxide particles have a concentration ratio calculated as niobium atom concentration/titanium atom concentration at the particle center, and the niobium atom concentration/titanium 9. The process cartridge according to claim 8, wherein the concentration ratio calculated by atomic concentration is 2.0 times or more. 9. A process cartridge according to claim 8, wherein said niobium atom-containing titanium oxide particles contain 2.6% by mass or more and 10.0% by mass or less of niobium atoms. In the electrophotographic photoreceptor,
The content of the conductive particles is 40.0% by volume or more and 70.0% by volume or less of the surface protective layer,
2. The process cartridge according to claim 1, wherein the surface protective layer has a volume resistivity of 1.0*10 ^{<10 >} [Omega].cm or more and 1.0*10 ^<14 > [Omega].cm or less.

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