Electrophotographic apparatus and process cartridge

Abstract

The invention relates to an electrophotographic apparatus and a process cartridge. Provided is an electrophotographic device having high positively charged properties even in an electrophotographic device using both a toner containing alumina particles as an external additive and a photosensitive member containing a polyarylate resin having excellent mechanical strength. In an electrophotographic apparatus, an electrophotographic photosensitive member includes a single layer type photosensitive layer including a charge generating material, a hole transporting material, an electron transporting material, and a binder resin, the photosensitive layer including a polyarylate resin having a structural unit represented by formula (1) and a structural unit represented by formula (2) as the binder resin, the toner is a toner including toner particles each including a toner base particle and an external additive attached to a surface of the toner base particle, the external additive including at least alumina particles.

Description

Technical Field

[0001] The present invention relates to an electrophotographic apparatus and a process cartridge. Background Art

[0002] In recent years, electrophotographic apparatuses having a longer service life are required, while being expected to have high image quality stability even when used repeatedly.

[0003] The charging stability of the toner is an important factor in achieving high image quality stability. In Japanese Patent Application Laid-Open No. 2023-66052, a toner using aluminum oxide particles as an external additive for the purpose of improving the positive chargeability of the toner has been proposed.

[0004] Meanwhile, an organic electrophotographic photosensitive member (hereinafter sometimes simply referred to as "electrophotographic photosensitive member" or "photosensitive member") containing an organic photoconductive material (charge generating material) is used as an electrophotographic photosensitive member to be mounted to an electrophotographic apparatus or a process cartridge.

[0005] In Japanese Patent Application Laid-Open No. 2017-49298, a photosensitive member including a polyarylate resin excellent in mechanical strength has been proposed.

[0006] According to the research conducted by the inventors of the present invention, a toner using aluminum oxide particles as an external additive has a problem when used in an electrophotographic apparatus having a long service life, because the aluminum oxide particles themselves are relatively hard and thus easily wear the surface of the photosensitive member. In addition, when a polyarylate resin having excellent mechanical strength is used in the surface layer of the photosensitive member in order to solve the above-mentioned problem, although the durability of the photosensitive member is improved, the polyarylate resin itself is easily positively charged, as a result of which the positive chargeability of the positively charged toner using the aluminum oxide particles in particular may be impaired.

[0007] Therefore, an object of the present invention is to provide an electrophotographic apparatus having high positive chargeability even in an electrophotographic apparatus using both a toner containing aluminum oxide particles as an external additive and a photosensitive member containing a polyarylate resin excellent in mechanical strength. Summary of the invention

[0008] The above-mentioned object is achieved by the present invention described below. That is, according to the present invention, there is provided an electrophotographic apparatus, which includes: an electrophotographic photosensitive member; a charging unit configured to charge the surface of the electrophotographic photosensitive member; an exposure unit configured to irradiate the charged surface of the electrophotographic photosensitive member with light to form an electrostatic latent image on the surface of the electrophotographic photosensitive member; a developing unit, which includes a toner and is configured to develop the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with the toner to form a toner image on the surface of the electrophotographic photosensitive member; and a transfer unit configured to transfer the toner image from the electrophotographic photosensitive member to the surface of the electrophotographic photosensitive member. The surface of a photographic photosensitive member is transferred onto a transfer material, wherein the electronic photographic photosensitive member includes a single-layer photosensitive layer comprising a charge generating material, a hole transporting material, an electron transporting material and a binder resin, wherein the photosensitive layer contains a polyarylate resin having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2) as a binder resin, wherein the colorant is a colorant containing colorant particles, wherein the colorant particles each contain a colorant base particle and an external additive attached to the surface of the colorant base particle, and wherein the external additive contains at least aluminum oxide particles.

[0009]

[0010] In addition, according to the present invention, a processing box is provided, which includes: an electronic photographic photosensitive member; and a developing unit, which includes a colorant and is constructed to form a colorant image on the surface of the electronic photographic photosensitive member with the colorant, wherein the processing box integrally supports the electronic photographic photosensitive member and the developing unit and is detachably mounted to the main body of the electronic photographic device, wherein the electronic photographic photosensitive member includes a single-layer photosensitive layer including a charge generating material, a hole transporting material, an electron transporting material and a binder resin, wherein the photosensitive layer includes a polyarylate resin having a structural unit represented by formula (1) and a structural unit represented by formula (2) as a binder resin, wherein the colorant is a colorant containing colorant particles, wherein the colorant particles each include a colorant base particle and an external additive attached to the surface of the colorant base particle, and wherein the external additive includes at least aluminum oxide particles.

[0011] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a diagram for explaining one example of the layer configuration of the electrophotographic photosensitive member according to the present invention.

[0013] Figure 2 is a diagram for explaining one example of the layer configuration of the electrophotographic photosensitive member according to the present invention.

[0014] Figure 3 is a diagram for explaining one example of the layer configuration of the electrophotographic photosensitive member according to the present invention.

[0015] Figure 4 is a diagram for explaining one example of the cross-sectional structure of toner particles in the toner according to the present invention.

[0016] Figure 5 is a diagram for explaining one example of a schematic configuration of an electrophotographic apparatus including a process cartridge including the electrophotographic photosensitive member according to the present invention.

[0017] Figure 6 is a diagram for explaining an example of a measuring device. DETAILED DESCRIPTION

[0018] The present invention is described in detail below by way of exemplary embodiments.

[0019] It has been found that when a photosensitive member containing a polyarylate resin in a surface layer of the photosensitive member is used in an electrophotographic apparatus using a toner containing aluminum oxide as an external additive, the positive charging stability of the toner is reduced. It is presumed that this is caused by the fact that the polyarylate resin used in the photosensitive member is easily positively charged, thereby partially reducing the positive charging property of the toner in contact with the polyarylate resin.

[0020] Based on the above assumption, the present inventors conducted various studies on a photosensitive member containing a polyarylate resin in a surface layer in an electrophotographic apparatus using a toner containing aluminum oxide as an external additive, thereby achieving the configuration of the present invention.

[0021] That is, the inventors have found the following situation: in an electronic photographic device including a colorant containing aluminum oxide as an external additive and a photosensitive member using a polyarylate resin in the surface layer of the photosensitive member, when the photosensitive member includes a single-layer photosensitive layer containing a charge generating material, a hole transporting material, an electron transporting material and a binder resin, and the photosensitive layer contains a polyarylate resin having a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), a structural unit represented by the following formula (3) and a structural unit represented by the following formula (4) as a binder resin, even in an electronic photographic device using both a colorant containing aluminum oxide as an external additive and a photosensitive member containing a polyarylate resin in the surface layer of the photosensitive member, a decrease in positive charging can be suppressed and positive charging stability can be maintained.

[0022] The structural unit represented by the following formula (1) exhibits a structure having high electron accepting property. In addition, when the structural unit represented by the formula (1) is bonded to the structural unit represented by the following formula (2), the structural unit represented by the formula (1) has resonance stabilization and higher electron accepting property. It is believed that an electrophotographic photosensitive member containing a polyarylate resin having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2) enhances the positive chargeability of the toner during toner development and transfer. That is, it is speculated that in the case of introducing a polyarylate resin having high electron accepting property, the electrophotographic photosensitive member can be used without damaging the positive chargeability of the toner using aluminum oxide as an external additive.

[0023] The electrophotographic apparatus of the present invention is an electrophotographic apparatus comprising: an electrophotographic photosensitive member; a charging unit configured to charge a surface of the electrophotographic photosensitive member; an exposure unit configured to irradiate the charged surface of the electrophotographic photosensitive member with light to form an electrostatic latent image on the surface of the electrophotographic photosensitive member; a developing unit including a toner and configured to develop the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with the toner to form a toner image on the surface of the electrophotographic photosensitive member; and a transfer unit configured to transfer the toner image from the electrophotographic photosensitive member to the surface of the electrophotographic photosensitive member. The surface of a photographic photosensitive member is transferred onto a transfer material, wherein the electronic photographic photosensitive member includes a single-layer photosensitive layer comprising a charge generating material, a hole transporting material, an electron transporting material and a binder resin, wherein the photosensitive layer contains a polyarylate resin having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2) as a binder resin, wherein the colorant is a colorant containing colorant particles, wherein the colorant particles each contain a colorant base particle and an external additive attached to the surface of the colorant base particle, and wherein the external additive contains at least aluminum oxide particles.

[0024]

[0025] The present invention is described below.

[0026] [Electrophotographic photosensitive member]

[0027] In the electrophotographic apparatus of the present invention, the electrophotographic photosensitive member includes a single-layer type photosensitive layer containing a charge generating material, a hole transporting material, an electron transporting material and a binder resin. Preferably, the electrophotographic photosensitive member of the present invention includes at least a support and a photosensitive layer formed on the support.

[0028] The method for producing an electrophotographic photosensitive member of the present invention is, for example, a method involving: preparing a coating liquid for each layer described later; applying the liquid in a desired layer order; and drying the liquid. In this case, examples of the method for applying the coating liquid include dip coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire rod coating, ring coating, and the like. Among them, dip coating is preferred from the viewpoint of efficiency and productivity.

[0029] The details are described below.

[0030] (Single-layer type photosensitive member)

[0031] Refer to the following Figures 1 to 3 A single-layer type photosensitive member 1 as an example of the photosensitive member of the embodiment is described. Figures 1 to 3 Each is a partial cross-sectional view for explaining a single-layer type photosensitive member 1. Figure 1 As shown, the single-layer photosensitive member 1 includes, for example, a conductive support 2 and a photosensitive layer 3. The photosensitive layer 3 included in the single-layer photosensitive member 1 is a single layer (single layer). The single-layer photosensitive layer 3 is a single-layer photosensitive layer 3s as a first photosensitive layer. Figure 2 As shown, the single-layer photosensitive member 1 may further include an undercoat layer 4 (intermediate layer) in addition to the conductive support 2 and the single-layer photosensitive layer 3s. The undercoat layer 4 is formed between the conductive support 2 and the single-layer photosensitive layer 3s. Figure 1 As shown in FIG. 1 , the single-layer photosensitive layer 3s can be directly formed on the conductive support 2. Alternatively, as shown in FIG. Figure 2 As shown in FIG. 1 , the single-layer photosensitive layer 3s can also be formed on the conductive support 2 through the intervention of the intermediate layer 4. Figure 3 As shown in FIG. 1 , the single-layer photosensitive member 1 may further include a protective layer 5 in addition to the conductive support 2 and the single-layer photosensitive layer 3s. The protective layer 5 is formed on the single-layer photosensitive layer 3s. Figure 1 and Figure 2 As shown in FIGS. 1 and 1 , the single-layer photosensitive layer 3s is preferably formed as the outermost surface layer of the single-layer photosensitive member 1. When the single-layer photosensitive layer 3s containing a polyarylate resin (PAR) described later is formed as the outermost surface layer, it is easy to suppress a decrease in transfer efficiency after durability. Figure 3 As shown, the protective layer 5 may be formed as the outermost surface layer of the monolayer photosensitive member 1. In the electrophotographic photosensitive member of the present invention, the thickness of the photosensitive layer (monolayer photosensitive layer 3s) is preferably 5 μm or more and 100 μm or less, more preferably 25 μm or more and 50 μm or less. The monolayer photosensitive layer 3s as the first photosensitive layer contains a charge generating material, a binder resin, an electron transporting material, and a hole transporting material.

[0032] <Support>

[0033] In the present invention, the electrophotographic photosensitive member includes a support. In the present invention, the support is preferably a conductive support having conductivity. In addition, examples of the shape of the support include cylindrical, belt-shaped, sheet-shaped, and the like. Among these shapes, a support having a cylindrical shape is preferred. In addition, the surface of the support may be subjected to an electrochemical treatment such as anodizing, a sandblasting treatment, or a cutting treatment, for example.

[0034] Metal, resin, glass, etc. are preferable as the material of the support.

[0035] Examples of the metal include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. An aluminum support using aluminum among these metals is preferred.

[0036] Furthermore, conductivity may be imparted to resin or glass through a treatment involving, for example, mixing the resin or glass with a conductive material or coating it with a conductive material.

[0037] <Base Coating>

[0038] In the present invention, an undercoat layer may be disposed on the support. The undercoat layer can improve the interlayer adhesion function and impart a charge injection suppression function.

[0039] The primer layer preferably contains a resin. Alternatively, the primer layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group.

[0040] Examples of the resin include polyester resins, polyarylate resins, polycarbonate resins, polyvinyl acetal resins, acrylic resins, epoxy resins, melamine resins, polyurethane resins, phenolic resins, polyvinylphenolic resins, alkyd resins, polyvinyl alcohol resins, polyethylene oxide resins, polypropylene oxide resins, polyamide resins, polyamic acid resins, polyimide resins, polyamideimide resins, and cellulose resins.

[0041] Examples of the polymerizable functional group of 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, a carboxylic anhydride group, and a carbon-carbon double bond group.

[0042] In order to improve electrical characteristics, the undercoat layer may further contain an electron transport material, a metal oxide, a metal, a conductive polymer, etc. Among them, an electron transport material and a metal oxide are preferably used.

[0043] Examples of electron transport materials include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadiene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, halogenated aryl compounds, silole compounds, and boron-containing compounds. An electron transport material having a polymerizable functional group can be used as the electron transport material, copolymerized with the above-mentioned monomer having a polymerizable functional group, thereby forming a primer layer as a cured film.

[0044] Examples of metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, and silicon dioxide. Examples of metals include gold, silver, and aluminum.

[0045] In addition, the undercoat layer may further contain additives.

[0046] The average thickness of the primer layer is preferably 0.1 μm or more and 50 μm or less, more preferably 0.2 μm or more and 40 μm or less, particularly preferably 0.3 μm or more and 30 μm or less.

[0047] The undercoat layer can be formed by: preparing an undercoat layer coating solution containing the above-mentioned materials and a solvent; forming a coating film of the coating solution; and drying and / or curing the coating film. Examples of the solvent used in the coating solution include alcohol solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents.

[0048] <Single-layer photosensitive layer>

[0049] In the present invention, the single-layer photosensitive layer is disposed on the support or on the undercoat layer disposed on the support.

[0050] The single-layer type photosensitive layer in the present invention is formed so as to contain at least a binder resin, a charge generating material, a hole transporting material, and an electron transporting material.

[0051] [Binder resin]

[0052] In the electrophotographic photosensitive member of the present invention, the photosensitive layer contains, as a binder resin, a polyarylate resin having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2).

[0053]

[0054] The structural unit represented by formula (1) is a structure having high electron accepting property. In addition, when the structural unit represented by formula (1) is bonded to the structural unit represented by formula (2), the structural unit represented by formula (1) has resonance stabilization and higher electron accepting property. It is conceivable that the electrophotographic photosensitive member containing the polyarylate resin having the structural unit represented by formula (1) and the structural unit represented by formula (2) enhances the positive chargeability of the toner when the positively charged toner is developed on the electrophotographic photosensitive member and transferred to the transfer member. It is presumed that, with this configuration, the electrophotographic photosensitive member is relatively negatively charged, and the positive chargeability of the toner is relatively increased, thereby reducing the transfer residual toner.

[0055] Furthermore, in the electrophotographic apparatus of the present invention, it is preferred that the polyarylate resin has a structural unit represented by the following formula (3) and a structural unit represented by the following formula (4) in addition to the structural unit represented by the formula (1) and the structural unit represented by the formula (2).

[0056]

[0057] When the polyarylate resin has a structural unit represented by formula (3) and a structural unit represented by formula (4), the solubility of the polyarylate resin in a solvent is improved, so that a photosensitive layer can be satisfactorily formed. The molecular structure of each chemical substance of the present invention can be determined by a nuclear magnetic resonance (NMR) device. In the present invention, "*" in each of formulas (1) to (4) represents a bonding site.

[0058] The photosensitive layer may contain resins other than the above-mentioned polyarylate resins to the extent that the effects of the present invention are not impaired. Examples of other resins include polycarbonate resins, styrene resins, and acrylic resins. The polyarylate resins may be, for example, random copolymers, alternating copolymers, periodic copolymers, or block copolymers.

[0059] Preferably, the polyarylate resin has a structural unit represented by formula (1), a structural unit represented by formula (2), a structural unit represented by formula (3) and a structural unit represented by formula (4), and when the number of moles of the structural unit represented by formula (1) in the total number of moles of the structural unit represented by formula (1) and the number of moles of the structural unit represented by formula (3) is represented by M1, the number of moles of the structural unit represented by formula (2) in the total number of moles of the structural unit represented by formula (4) is represented by M2. When the molar number of the structural unit is represented by M2, the molar number of the structural unit represented by formula (3) in the total amount of the molar number of the structural unit represented by formula (1) and the molar number of the structural unit represented by formula (3) is represented by M3, and the molar number of the structural unit represented by formula (4) in the total amount of the molar number of the structural unit represented by formula (2) and the molar number of the structural unit represented by formula (4) is represented by M4, 0.30≤M3 / (M1+M3)<0.7 and 0<M2 / (M2+M4)<0.5 are satisfied.

[0060] From the viewpoint of suppressing a decrease in transfer efficiency, M1 is preferably greater than 30%, more preferably 55% or more.

[0061] From the viewpoint of suppressing a decrease in transfer efficiency, M2 is preferably larger in terms of mole fraction, but from the viewpoint of solubility in a solvent, M2 is preferably less than 50%. When the solubility in a solvent is improved, a photosensitive layer can be satisfactorily formed.

[0062] From the viewpoint of solubility in a solvent, M3 is preferably 35% or more and less than 70%.

[0063] From the viewpoint of suppressing the reduction of transfer efficiency, M4 is preferably 80% or less, and from the viewpoint of solubility in solvent, it is preferably greater than 50%. The molecular structure of each chemical substance of the present invention can be determined by a nuclear magnetic resonance (NMR) device. In addition, each chemical substance can be quantified by NMR or by NMR and gas chromatography-mass spectrometry (CG-MS).

[0064] In the electrophotographic photosensitive member of the present invention, in the above-mentioned polyarylate resin, the sum of the ratio of the substance amounts of the structural unit represented by formula (1) and the ratio of the substance amounts of the structural unit represented by formula (3) relative to the sum of the substance amounts of the structural units derived from the dicarboxylic acid for forming the polyarylate resin is preferably 0.50 or more.

[0065] In the electrophotographic photosensitive member of the present invention, in the above-mentioned polyarylate resin, the sum of the ratio of the amount of the structural unit represented by formula (2) and the ratio of the amount of the structural unit represented by formula (4) relative to the total amount of the structural unit derived from bisphenol used to form the polyarylate resin is preferably greater than 0 and less than 0.50.

[0066] In the electrophotographic photosensitive member of the present invention, it is more preferred that the amount of the structural unit represented by formula (1) relative to the total amount of the structural unit derived from dicarboxylic acid used to form the polyarylate resin is 0.50 or more. Here, the amount is in moles.

[0067] The viscosity average molecular weight of the polyarylate resin (PAR) is preferably 10,000 or more, more preferably 30,000 or more, and even more preferably 50,000 or more. When the viscosity average molecular weight of the polyarylate resin (PAR) is 10,000 or more, the wear resistance of the photosensitive member is improved. At the same time, the viscosity average molecular weight of the polyarylate resin (PAR) is preferably 80,000 or less, more preferably 70,000 or less. When the viscosity average molecular weight of the polyarylate resin (PAR) is 80,000 or less, the polyarylate resin (PAR) is easily dissolved in a solvent for forming a photosensitive layer. The viscosity average molecular weight can be obtained by a known method.

[0068] Examples of bisphenols used to form bisphenol-derived repeating units (structural units represented by formula (2) and structural units represented by formula (4)) include compounds represented by formula (BP-2) and compounds represented by formula (BP-5) (the compound represented by formula (BP-2) is sometimes referred to as "compound (BP-2)" hereinafter, and the compound represented by formula (BP-5) is sometimes referred to as "compound (BP-5)" hereinafter). Examples of dicarboxylic acids used to form dicarboxylic acid-derived repeating units (structural units represented by formula (1) and structural units represented by formula (3)) include compounds represented by formula (DC-1) and compounds represented by formula (DC-4) (the compound represented by formula (DC-1) is sometimes referred to as "compound (DC-1)" hereinafter, and the compound represented by formula (DC-4) is sometimes referred to as "compound (DC-4)" hereinafter). The bisphenol ratio in the resin can be adjusted by changing the amounts of compound (BP-1) and compound (BP-2) added when producing the polyarylate resin (PAR). In addition, the amount of dicarboxylic acid in the resin, that is, the dicarboxylic acid ratio can be similarly adjusted by changing the amounts of the compound (DC-1) and the compound (DC-4) added during production.

[0069]

[0070] Bisphenols (e.g., compound (BP-2) and compound (BP-5)) can each be used by derivatization to aromatic diacetates. Dicarboxylic acids (e.g., compound (DC-1) and compound (DC-4)) can each be used by derivatization. Examples of derivatives of dicarboxylic acids include dicarboxylic acid dichlorides, dicarboxylic acid dimethyl esters, dicarboxylic acid diethyl esters, and dicarboxylic acid anhydrides. Dicarboxylic acid dichlorides are compounds obtained by replacing two "-C(=O)-OH" groups of dicarboxylic acids with "-C(=O)-Cl" groups.

[0071] In the polycondensation of bisphenol and dicarboxylic acid, one or both of a base and a catalyst may be added. An example of the base is sodium hydroxide. Examples of the catalyst include benzyltributylammonium chloride, ammonium chloride, ammonium bromide, quaternary ammonium salts, triethylamine, and trimethylamine.

[0072] The photosensitive layer may contain only the polyarylate resin (PAR) as the binder resin, and may further contain a binder resin other than the above (hereinafter sometimes referred to as “other binder resin”). Examples of other binder resins include: thermoplastic resins (more specifically, polyester resins other than polyarylate resins (PAR), polycarbonate resins, styrene resins, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, styrene-acrylic acid copolymers, acrylic copolymers, polyethylene resins, ethylene-vinyl acetate copolymers, chlorinated polyethylene resins, polyvinyl chloride resins, polypropylene resins, ionomers, vinyl chloride-vinyl acetate copolymers, polyester resins, alkyd resins, polyamide resins, polyurethane resins, polysulfone resins, diallyl phthalate resins, ketone resins, polyvinyl butyral resins, polyvinyl acetal resins, and polyether resins); thermosetting resins (more specifically, silicone resins, epoxy resins, phenolic resins, urea resins, melamine resins, and any other crosslinkable thermosetting resins); and photocurable resins (more specifically, epoxy-acrylic resins and urethane-acrylic copolymers).

[0073] In the electrophotographic photosensitive member of the present invention, the ratio of the resin having at least the structural unit represented by the formula (1) and the structural unit represented by the formula (2) in the binder resin is preferably 50% by mass or more. In addition, in the electrophotographic photosensitive member of the present invention, the ratio of the mass of the polyarylate resin to the mass of the binder resin is preferably 50% by mass or more.

[0074] The structure of the polyarylate resin of the present invention can be 1 H-NMR spectroscopy was used to determine the 1 H-NMR spectroscopy was performed using 1 The H-nuclear magnetic resonance spectroscopy (proton NMR) was used to analyze the components of the polymer components recovered from the photosensitive layer.

[0075] A specific analysis method of the polyarylate resin in the photosensitive layer when the photosensitive member is a cylindrical body is described below.

[0076] (Re-precipitation of resin in the photosensitive layer)

[0077] The photosensitive member (cylindrical body) was cut with a wire saw at a position 10 cm away from the end in the generatrix direction of the photosensitive member.

[0078] • Wipe the inner surface of the cut cylinder of 10 cm with lens cleaning paper impregnated with chloroform.

[0079] To wash off the photosensitive layer, immerse the 3 cm end of the cut cylinder in chloroform. (Put about 60 mL of chloroform in a 100 mL beaker and immerse the end for 5 minutes at room temperature.)

[0080] The chloroform solution from which the above-mentioned photosensitive layer was eluted was concentrated to 2 ml using a rotary evaporator to provide a concentrated solution, and the concentration was stopped.

[0081] 50 mL of a methanol / acetone mixed solution (volume ratio: 1:1) was prepared, and the entire amount of the concentrated solution was added dropwise thereto while stirring the mixed solution, thereby performing reprecipitation.

[0082] Suction filtration was performed using a funnel (funnel: SU-40, filter paper: No. 5C-40, manufactured by Kiriyama Glass Co.).

[0083] The residue on the filter paper was recovered with a spatula and dried in vacuo (70°C, 1 hour).

[0084] (NMR measurement)

[0085] To prepare a measurement sample, 20 mg of a sample was dissolved in 1 g of deuterated chloroform containing tetramethylsilane as a reference material, and the entire amount thereof was transferred to an NMR tube.

[0086] (Deuterated chloroform: manufactured by Sigma-Aldrich Japan GK, Chloroform-d, model: 612200)

[0087] (NMR tube: manufactured by Norell, Inc., ST500-7, model: S3010)

[0088] NMR measurement

[0089] Equipment: AVANCE 500 manufactured by Bruker

[0090] Conditions: Proton NMR, automatically measured by Icon-NMR

[0091] Scan times: 32 times

[0092] Reference peak: The peak of the methyl group of tetramethylsilane was set to 0 ppm.

[0093] [Charge generating material]

[0094] Examples of charge generating materials include phthalocyanine pigments, perylene pigments, disazo pigments, triazo pigments, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squarylium pigments, indigo pigments, azulenium pigments, cyanine pigments, powders of inorganic photoconductive materials (e.g., selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, and amorphous silicon), pyrylium pigments, anthraquinone pigments, triphenylmethane pigments, reduced pigments, toluidine pigments, pyrazoline pigments, and quinacridone pigments. The photosensitive layer may contain only one charge generating material, or may contain two or more charge generating materials.

[0095] Phthalocyanine pigments are pigments having a phthalocyanine structure. Examples of phthalocyanine pigments include metal-free phthalocyanine and metal phthalocyanine. Examples of metal phthalocyanine include oxytitanium phthalocyanine, hydroxygallium phthalocyanine and chlorogallium phthalocyanine. Metal phthalocyanine is preferably oxytitanium phthalocyanine. Oxytitanium phthalocyanine is represented by formula (CGM-1).

[0096]

[0097] Phthalocyanine pigments may be crystalline or amorphous. Examples of crystals of metal-free phthalocyanine are X-type crystals of metal-free phthalocyanine (X-type crystals of metal-free phthalocyanine are sometimes referred to as "X-type metal-free phthalocyanine" below). Examples of crystals of oxytitanium phthalocyanine include α-type, β-type, and Y-type crystals of oxytitanium phthalocyanine (α-type, β-type, and Y-type crystals of oxytitanium phthalocyanine are sometimes referred to as "α-type oxytitanium phthalocyanine", "β-type oxytitanium phthalocyanine", and "Y-type oxytitanium phthalocyanine" below). For example, in digital optical electronic photographic equipment (for example, a laser beam printer or fax machine using a light source such as a semiconductor laser), it is preferred to use a photosensitive member having sensitivity in a wavelength region of 700 nm or more. The charge generating material preferably contains a phthalocyanine pigment, more preferably contains metal-free phthalocyanine or oxytitanium phthalocyanine, still more preferably contains oxytitanium phthalocyanine, and particularly preferably contains Y-type oxytitanium phthalocyanine, because each of these materials has a high quantum yield in a wavelength region of 700 nm or more.

[0098] Y-type oxytitanium phthalocyanine has a main peak at a Bragg angle (2θ±0.2°) of 27.2° in the CuKα characteristic X-ray diffraction spectrum. The main peak in the CuKα characteristic X-ray diffraction spectrum is a peak having the first or second maximum intensity within the range of the Bragg angle (2θ±0.2°) of 3° to 40°. Y-type oxytitanium phthalocyanine does not have a peak at 26.2° in the CuKα characteristic X-ray diffraction spectrum.

[0099] The CuKα characteristic X-ray diffraction spectrum can be measured, for example, by the following method. First, a sample (oxytitanium phthalocyanine) is placed in a sample holder of an X-ray diffraction apparatus (e.g., "RINT 1100" manufactured by Rigaku Corporation) and the CuKα characteristic X-ray wavelength is 0.0407 W. The X-ray diffraction spectrum is measured under the conditions of. The measurement range (2θ) is, for example, 3° or more and 40° or less (start angle: 3°, stop angle: 40°), and the scanning speed is, for example, 10° / min. The main peak is determined from the obtained X-ray diffraction spectrum, and the Bragg angle of the main peak is read.

[0100] The content of the charge generating material is preferably 0.1 parts by mass or more and 50 parts by mass or less, and more preferably 0.5 parts by mass or more and 5 parts by mass or less, based on 100 parts by mass of the binder resin.

[0101] [Electron Transport Materials]

[0102] In the electrophotographic apparatus of the present invention, it is preferred that the electron transport material comprises a compound represented by the following formula (10), a compound represented by the following formula (11), a compound represented by the following formula (12), a compound represented by the following formula (13), a compound represented by the following formula (14), a compound represented by the following formula (15), or a compound represented by the following formula (16). It is believed that the introduction of the above electron transport material into the photosensitive layer improves the compatibility between the binder resin in the present invention and the hole transport material described later to improve the uniformity of the photosensitive layer, thereby enhancing the effect of the present invention.

[0103]

[0104]

[0105] Q in formula (10) 1 and Q 2 , Q in formula (11) 11 , Q 12 and Q 13 , Q in formula (12) 21 , Q 22 , Q 23 and Q 24 , Q in formula (13) 31 and Q 32 , Q in formula (14) 41 , Q 42 , Q 43 and Q 44 , Q in formula (15) 51 , Q 52 , Q53 , Q 54 , Q 55 and Q 56 And Q in formula (16) 61 and Q 62 Each independently represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms which may be substituted with at least one substituent selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom. 1 and Y 2 Each independently represents an oxygen atom or a sulfur atom.

[0106] Preferably, Q in formula (10) 1 and Q 2 , Q in formula (11) 11 To Q 13 , Q in formula (12) 21 To Q 24 , Q in formula (13) 31 and Q 32 , Q in formula (14) 41 To Q 44 , Q in formula (15) 51 To Q 56 And Q in formula (16) 61 and Q 62 Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms which may be substituted with at least one substituent selected from the group consisting of an alkyl group having 1 to 6 carbon atoms and a halogen atom. Preferably, Y in formula (15) 1 and Y 2 Each represents an oxygen atom.

[0107] From Q in formula (10), 1 and Q 2 , Q in formula (11) 11 To Q 13 , Q in formula (12) 21 To Q 24 , Q in formula (13) 31 and Q 32 , Q in formula (14) 41 To Q 44 , Q in formula (15) 51 To Q 56 And Q in formula (16) 61 and Q 62The alkyl group having 1 to 6 carbon atoms each represented is preferably an alkyl group having 1 to 5 carbon atoms, more preferably a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group, and particularly preferably a methyl group, an isopropyl group, a tert-butyl group or a 1,1-dimethylpropyl group.

[0108] From Q in formula (10), 1 and Q 2 , Q in formula (11) 11 To Q 13 , Q in formula (12) 21 To Q 24 , Q in formula (13) 31 and Q 32 , Q in formula (14) 41 To Q 44 , Q in formula (15) 51 To Q 56 And Q in formula (16) 61 and Q 62 The aryl group having 6 or more and 14 or less carbon atoms represented by each is preferably an aryl group having 6 or more and 10 or less carbon atoms, and more preferably a phenyl group. The aryl group having 6 or more and 14 or less carbon atoms may be substituted with at least one substituent selected from the group consisting of an alkyl group having 1 or more and 6 or less carbon atoms and a halogen atom. The alkyl group having 1 or more and 6 or less carbon atoms as a substituent is preferably an alkyl group having 1 or more and 3 or less carbon atoms, and more preferably a methyl group or an ethyl group. The halogen atom as a substituent is preferably a fluorine atom, a chlorine atom or a bromine atom, and particularly preferably a chlorine atom. When the aryl group having 6 or more and 14 or less carbon atoms is substituted with a substituent, the number of substituents is preferably 1 or more and 5 or less, and more preferably 1 or 2. The aryl group having 6 or more and 14 or less carbon atoms substituted with at least one substituent selected from the group consisting of an alkyl group having 1 or more and 6 or less carbon atoms and a halogen atom is preferably a chlorophenyl group, a dichlorophenyl group or an ethylmethylphenyl group, and more preferably a 4-chlorophenyl group, a 2,5-dichlorophenyl group or a 2-ethyl-6-methylphenyl group.

[0109] From Q in formula (10), 1 and Q 2 , Q in formula (11) 11 To Q 13 , Q in formula (12) 21 To Q 24 , Q in formula (13) 31 and Q 32 , Q in formula (14) 41 To Q 44 , Q in formula (15) 51 To Q 56 And Q in formula (16) 61 and Q 62The alkenyl groups each representing a carbon number of 2 or more and 6 or less are preferably vinyl, 1-propenyl, 2-propenyl, 1-methylvinyl, 1-butenyl, 1-ethylvinyl, 1-methyl-2-propenyl, 2-butenyl, 3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, pentenyl, or hexenyl.

[0110] From Q in formula (10), 1 and Q 2 , Q in formula (11) 11 To Q 13 , Q in formula (12) 21 To Q 24 , Q in formula (13) 31 and Q 32 , Q in formula (14) 41 To Q 44 , Q in formula (15) 51 To Q 56 And Q in formula (16) 61 and Q 62 The alkoxy group having 1 to 6 carbon atoms each preferably is a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a tert-butoxy group, a pentyloxy group, or a hexyloxy group.

[0111] In the electrophotographic apparatus of the present invention, it is preferred that the electron transport material contains a compound represented by the following formula (E-1), a compound represented by the following formula (E-2), a compound represented by the following formula (E-3), a compound represented by the following formula (E-4), a compound represented by the following formula (E-5), a compound represented by the following formula (E-6), a compound represented by the following formula (E-7), or a compound represented by the following formula (E-8). A suitable example of the compound represented by formula (10) (hereinafter sometimes referred to as "electron transport material (10)") is a compound represented by the following formula (E-4). A suitable example of the electron transport material (11) is a compound represented by the following formula (E-5). A suitable example of the electron transport material (12) is a compound represented by the following formula (E-7). A suitable example of the electron transport material (13) is a compound represented by the following formula (E-6). A suitable example of the electron transport material (14) is a compound represented by the following formula (E-8). Suitable examples of the electron transport material (15) include compounds represented by the following formula (E-2) and by the following formula (E-3). Suitable examples of the electron transport material (16) are compounds represented by the following formula (E-1). The compounds represented by the following formula (E-1) to the following formula (E-8) are hereinafter sometimes referred to as "electron transport material (E-1)" to "electron transport material (E-8)", respectively.

[0112]

[0113]

[0114]

[0115] The content of the electron transport material is preferably 5 parts by mass or more and 150 parts by mass or less, more preferably 10 parts by mass or more and 100 parts by mass or less, and still more preferably 30 parts by mass or more and 70 parts by mass or less, relative to 100 parts by mass of the binder resin. The photosensitive layer may contain only one electron transport material, or may contain two or more electron transport materials.

[0116] [Hole transport material]

[0117] In the electrophotographic photosensitive member of the present invention, it is preferred that the hole transport material contains a compound represented by the following formula (20), a compound represented by the following formula (21), a compound represented by the following formula (22), a compound represented by the following formula (23), or a compound represented by the following formula (24). It is considered that the introduction of the above hole transport material into the photosensitive layer improves the compatibility between the binder resin and the electron transport material in the present invention to improve the uniformity of the photosensitive layer, thereby enhancing the effect of the present invention.

[0118]

[0119]

[0120]

[0121] In formula (20), R 11 , R 12 , R 13 and R 14 Each independently represents an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and a1, a2, a3 and a4 each independently represent an integer of 0 to 5. In formula (20), when a1 represents an integer of 2 to 5, a plurality of R 11 When a2 represents an integer of 2 to 5, a plurality of R 12 When a3 represents an integer of 2 to 5, a plurality of R 13 When a4 represents an integer of 2 to 5, a plurality of R 14 can represent groups that are the same as or different from each other. 11 , R 12 , R 13 and R 14Each independently represents an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group or an ethyl group. a1, a2, a3, and a4 each independently represent an integer of 1 to 3, and more preferably 1. 11 , R 12 , R 13 and R 14 Each independently preferably represents an alkoxy group having 1 to 6 carbon atoms, and more preferably represents a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a tert-butoxy group, a pentyloxy group, and a hexyloxy group.

[0122] In formula (21), R 21 , R 22 and R 23 Each independently represents preferably an alkyl group having 1 to 6 carbon atoms, more preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl or hexyl, and R 24 , R 25 and R 26 Each independently represents preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group or a hexyl group, and b1, b2 and b3 each independently represent 0 or 1. In formula (21), R 21 , R 22 and R 23 Each independently represents preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group, an ethyl group, an n-propyl group or an isopropyl group, and particularly preferably a methyl group. 21 , R 22 and R 23 Each is preferably bonded to the meta position of the phenyl group relative to the vinyl group or the butadienyl group. 24 , R 25 and R 26 Preferably, b1, b2 and b3 all represent 0 or 1.

[0123] In formula (22), R 31 , R 32 and R 33 Each independently represents preferably an alkyl group having 1 to 6 carbon atoms, more preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl or hexyl, and R 34 Preferably, it represents an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, more preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group or a hydrogen atom, and d1, d2 and d3 each independently represent an integer of 0 to 5. In formula (22), when d1 represents an integer of 2 to 5, a plurality of R 31When d2 represents an integer of 2 to 5, a plurality of R 32 When d3 represents an integer of 2 to 5, a plurality of R 33 can represent groups that are the same as or different from each other. 34 Preferably, d1, d2 and d3 each represent 0.

[0124] In formula (23), R 41 , R 42 , R 43 , R 44 , R 45 and R 46 Each independently represents preferably an alkyl group having 1 to 6 carbon atoms or a phenyl group, more preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group or a phenyl group, and R 47 and R 48 Each independently represents preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, more preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, or a phenyl group; e1, e2, e3, and e4 each independently represent an integer of 0 to 5; e5 and e6 each independently represent an integer of 0 to 4; and e7 and e8 each independently represent 0 or 1. In formula (23), when e1 represents an integer of 2 to 5, a plurality of R 41 When e2 represents an integer of 2 to 5, multiple R 42 When e3 represents an integer of 2 or more and 5 or less, a plurality of R 43 When e4 represents an integer of 2 or more and 5 or less, a plurality of R 44 When e5 represents an integer of 2 or more and 4 or less, a plurality of R 45 When e6 represents an integer of 2 or more and 4 or less, a plurality of R 46 can represent groups that are the same as or different from each other. 41 To R 46 Each independently represents preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and still more preferably a methyl group or an ethyl group. 47 and R 48Each preferably represents a hydrogen atom. Preferably, e1, e2, e3 and e4 each independently represent an integer greater than 0 and less than 2. More preferably, e1 and e2 each represent 0, and e3 and e4 each represent 2. e5 and e6 each preferably represent 0. Preferably, e7 and e8 both represent 0 or both represent 1.

[0125] In formula (24), R 50 and R 51 each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group, and R 52 , R 53 , R 54 , R 55 , R 56 , R 57 and R 58 Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group which may be substituted by an alkyl group having 1 to 6 carbon atoms. The alkyl group having 1 to 6 carbon atoms preferably represents a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group or a hexyl group. The alkoxy group having 1 to 6 carbon atoms preferably represents a methoxy group, an ethoxy group, a n-propoxy group, an isopropoxy group, a n-butoxy group, an isobutoxy group, a tert-butoxy group, a pentyl group or a hexyl group. f1 and f2 each independently represent an integer of 0 to 2, and f3 and f4 each independently represent an integer of 0 to 5. In formula (24), when f3 represents an integer of 2 to 5, multiple R 50 When f4 represents an integer of 2 or more and 5 or less, a plurality of R 51 may represent groups that are the same as or different from each other.

[0126] In formula (24), R 50 and R 51 Each independently represents preferably an alkyl group having 1 to 6 carbon atoms, and more preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl or hexyl. 52 and R 53 Each represents a hydrogen atom or a phenyl group which may be substituted by an alkyl group having 1 to 6 carbon atoms. Here, the alkyl group having 1 to 6 carbon atoms is preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group or a hexyl group. Preferably, R 54 To R 58Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. Here, the alkyl group having 1 to 6 carbon atoms preferably represents a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, or a hexyl group. The alkoxy group having 1 to 6 carbon atoms preferably represents a methoxy group, an ethoxy group, a n-propoxy group, an isopropoxy group, a n-butoxy group, an isobutoxy group, a tert-butoxy group, a pentyl group, or a hexyl group. Preferably, f1 and f2 both represent 0, both represent 1, or both represent 2. Preferably, f3 and f4 each independently represent 0 or 1.

[0127] By R 50 and R 51 The alkyl group having 1 to 6 carbon atoms each represents is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group, an ethyl group, an n-propyl group or an isopropyl group, and particularly preferably a methyl group. 52 and R 53 The phenyl group which may be substituted by an alkyl group having 1 to 6 carbon atoms represented by each is preferably a phenyl group or a phenyl group substituted by an alkyl group having 1 to 3 carbon atoms. The phenyl group substituted by an alkyl group having 1 to 3 carbon atoms is preferably a methylphenyl group, and more preferably a 4-methylphenyl group. 54 To R 58 Each of the alkyl groups having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably represents a methyl group, an ethyl group, or an n-butyl group. 54 To R 58 The alkoxy group having 1 to 6 carbon atoms each represented is preferably an alkoxy group having 1 to 3 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group or an isopropoxy group, and particularly preferably an ethoxy group.

[0128] In the electrophotographic apparatus of the present invention, it is preferred that the hole transport material contains a compound represented by the following formula (H-1), a compound represented by the following formula (H-2), a compound represented by the following formula (H-3), a compound represented by the following formula (H-4), a compound represented by the following formula (H-5), a compound represented by the following formula (H-6), a compound represented by the following formula (H-7), a compound represented by the following formula (H-8), a compound represented by the following formula (H-9), a compound represented by the following formula (H-10), or a compound represented by the following formula (H-11). Suitable examples of the hole transport material (20) are compounds represented by the following formula (H-11). Suitable examples of the hole transport material (21) include compounds represented by the following formula (H-7) and the following formula (H-8). Suitable examples of the hole transport material (22) are compounds represented by the following formula (H-6). Suitable examples of hole transport materials (23) include compounds represented by the following formula (H-9) and the following formula (H-10). Suitable examples of hole transport materials (24) include compounds represented by the following formula (H-1), the following formula (H-2), the following formula (H-3), the following formula (H-4) and the following formula (H-5). The compounds represented by the following formula (H-1) to the following formula (H-11) are hereinafter sometimes referred to as "hole transport material (H-1)" to "hole transport material (H-11)", respectively.

[0129]

[0130]

[0131]

[0132]

[0133]

[0134] The content of the hole transport material is preferably 10 parts by mass or more and 200 parts by mass or less, more preferably 30 parts by mass or more and 120 parts by mass or less, and even more preferably 50 parts by mass or more and 90 parts by mass or less, relative to 100 parts by mass of the binder resin. The photosensitive layer may contain only one hole transport material, or may contain two or more hole transport materials. In addition, the photosensitive layer may also contain hole transport materials other than the compound represented by formula (20), the compound represented by formula (21), the compound represented by formula (22), the compound represented by formula (23), and the compound represented by formula (24) (hereinafter sometimes referred to as "other hole transport materials"). Examples of other hole transport materials include triphenylamine derivatives, diamine derivatives (e.g., N,N,N′,N′-tetraphenylbenzidine derivatives, N,N,N′,N′-tetraphenylphenylenediamine derivatives, N,N,N′,N′-tetraphenylnaphthalenediamine derivatives, N,N,N′,N′-tetraphenylphenanthrenediamine derivatives and di(aminophenylvinyl)benzene derivatives), oxadiazole compounds (e.g., 2,5-bis(4-methylaminophenyl)-1,3,4-oxadiazole), styryl compounds (e.g., 9-(4-diethylaminostyryl)anthracene), carbazole compounds (e.g., polyvinylcarbazole), organic polysilane compounds, pyrazoline compounds (e.g., 1-phenyl-3-(p-dimethylaminophenyl)pyrazoline), hydrazone compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds and triazole compounds.

[0135] [additive]

[0136] In the electrophotographic photosensitive member of the present invention, it is preferred that the photosensitive layer contains a compound represented by the following formula (T-1) as an additive. The photosensitive layer may contain additives as needed. Examples of additives include UV absorbers, antioxidants, free radical scavengers, singlet quenchers, softeners, surface modifiers, extenders, thickeners, waxes, donors, surfactants, plasticizers, sensitizers, and leveling agents. In particular, it is preferred to add a small amount of a substance represented by formula (T-1).

[0137]

[0138] [Toner]

[0139] In the electrophotographic apparatus of the present invention, the toner is a toner that exhibits positive chargeability and contains toner particles.

[0140] [Toner particles]

[0141] Figure 4 It is a diagram for explaining an example of the cross-sectional structure of a toner particle in the toner of the present embodiment. Figure 4 The toner particles 20 shown include toner base particles 10 and external additives attached to the surface of the toner base particles 10. The external additives include aluminum oxide particles 11. Figure 4 The structure of the toner particles in the toner is described. The toner particles in the toner of the present invention may have Figure 4 The toner particles 20 shown have different structures. For example, the toner base particles may have a core-shell structure.

[0142] The toner of the present invention is further described below.

[0143] [External additives]

[0144] In the electrophotographic apparatus of the present invention, the toner particles each contain a toner base particle and an external additive attached to the surface of the toner base particle, and the external additive contains aluminum oxide particles. In addition, in order to improve the performance of the toner, the external additive preferably contains organic particles, silica particles, etc. in addition to the aluminum oxide particles. (External additives other than aluminum oxide particles are hereinafter referred to as "other external additives").

[0145] [Alumina particles]

[0146] In the electrophotographic apparatus of the present invention, it is preferred that the toner base particles each contain a binder resin, and the amount of alumina particles (aluminum oxide particles) as an external additive is 0.1 parts by mass or more and 3.0 parts by mass or less relative to 100 parts by mass of the toner base particles.

[0147] In the electrophotographic apparatus of the present invention, the number average value of the major diameter of the aluminum oxide particles (the number average primary particle size of the aluminum oxide particles) is preferably 10 nm or more and 450 nm or less, and more preferably 60 nm or more and 450 nm or less. When the number average value of the major diameter is set to these ranges, the desorption of the aluminum oxide particles from the toner base particles can be suppressed, and even when a large number of images are printed, an image with a desired image density can be easily formed.

[0148] The amount of the aluminum oxide particles is preferably 0.1 parts by mass or more and 10 parts by mass or less, and more preferably 0.1 parts by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the toner base particles. The amount of the aluminum oxide particles is preferably 20 parts by mass or more and 60 parts by mass or less, and more preferably 30 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the external additive.

[0149] The aluminum oxide particles may each include a conductive layer covering the aluminum oxide base and a surface treatment layer covering the conductive layer except for the aluminum oxide base to an extent that the positive chargeability is not impaired.

[0150] [Alumina substrate]

[0151] The alumina matrix tends to exhibit positive chargeability, so the toner containing the alumina particles is easily positively charged. The content ratio of the alumina matrix in the alumina particles is preferably 80% by mass or more, more preferably 95% by mass or more, and still more preferably 100% by mass.

[0152] The alumina substrate can be obtained, for example, by calcining aluminum hydroxide and then pulverizing the resultant with a pulverizer, or commercially available alumina powder can be used. An example of commercially available alumina powder is high-purity alumina (AKP series) manufactured by Sumitomo Chemical Co., Ltd.

[0153] [Conductive layer]

[0154] The conductive layer is a layer formed using a conductive treatment agent. The aluminum oxide particles as an external additive each include a conductive layer, and thus the conductivity of the toner is appropriately improved.

[0155] The conductive layer preferably contains an oxide having conductivity, and more preferably contains a metal oxide having conductivity (the metal oxide having conductivity is sometimes referred to as "conductive metal oxide" below). Examples of conductive metal oxides include: metal oxides each containing tin oxide (e.g., antimony-doped tin oxide (ATO), indium tin oxide (ITO), and fluorine-doped tin oxide (FTO)); and metal oxides each containing zinc oxide (e.g., aluminum-doped zinc oxide (AZO) and gallium-doped zinc oxide (GZO)). The conductive layer preferably contains antimony-doped tin oxide. The content ratio of the conductive metal oxide in the conductive layer is preferably 80% by mass or more, more preferably 95% by mass or more, and even more preferably 100% by mass.

[0156] [Surface treatment layer]

[0157] The surface treatment layer is a layer formed by using a surface treatment agent. The surface treatment layer gives the toner satisfactory charging stability while suppressing the peeling of the conductive layer. The surface treatment agent is, for example, a hydrophobic treatment agent. Specific examples of the surface treatment agent include titanate coupling agents, aluminate coupling agents, and fatty acid metal salts.

[0158] In addition to the conductive layer and the surface treatment layer, the aluminum oxide particles can each further include other layers. In addition, the conductive layer can directly or indirectly cover the substrate. In addition, the surface treatment layer can directly or indirectly cover the conductive layer. In addition, the conductive layer and the surface treatment layer can each be multilayer.

[0159] <Method for measuring number average particle size of alumina particles>

[0160] A method for determining the number average particle size of alumina particles is described.

[0161] First, the positions of the aluminum oxide particles present on the toner surface are identified. The positions of the aluminum oxide particles can be identified by observation using an ultra-high resolution field emission scanning electron microscope S-4800 ((Hitachi High-Technologies Corporation) (SEM-EDX)) and elemental analysis.

[0162] Next, the major diameters of at least 200 aluminum oxide particles on the identification surface of the toner are measured and the average value is obtained. Although some aluminum oxide particles exist as aggregated particles, the particle size of such aggregated particles is not measured. In addition, the maximum diameter of each particle is used as the major diameter.

[0163] [Other external additives]

[0164] In the electrophotographic apparatus of the present invention, the external additive may contain strontium titanate particles. Examples of other external additives include: fluorine resin particles, such as vinylidene fluoride fine particles and polytetrafluoroethylene fine powder; silica fine particles, such as wet silica and dry silica, titanium oxide fine particles; hydrophobic fine particles obtained by surface treating the above particles with a hydrophobic treatment agent such as a silane compound, a titanium coupling agent or silicone oil; oxides, such as zinc oxide and tin oxide; composite oxides, such as strontium titanate, barium titanate, calcium titanate, strontium zirconate, calcium zirconate, etc.; and carbonate compounds, such as calcium carbonate and magnesium carbonate.

[0165] In the electrophotographic apparatus of the present invention, the external additive may include fluorine resin particles. In particular, fluorine resin particles are preferred because they improve the fluidity of the toner and partially impart positive charge to the toner when desorbed from the toner, resulting in improved positive charge stability of the toner.

[0166] [Toner base particles]

[0167] The toner base particles contain a binder resin as a main component. In addition, the toner base particles may contain an internal additive as required. Examples of the internal additive include a colorant, a release agent, a charge control agent, a charge control resin, and a magnetic powder.

[0168] [Binder resin]

[0169] Examples of the binder resin include conventionally known vinyl resins, polyester resins, polyurethane resins, and epoxy resins. Among them, vinyl resins, polyester resins, and polyurethane resins are preferred from the viewpoint of electrophotographic properties.

[0170] As the vinyl resin, for example, homopolymers of styrene and its substitution products, such as polystyrene, polyparachlorostyrene and polyvinyltoluene; styrene copolymers, such as styrene-parachlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-chloromethylmethacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, and styrene-acrylonitrile-indene copolymer; polyvinyl chloride, polyvinyl acetate, xylene resin, polyvinyl butyral and petroleum resin.

[0171] In particular, styrene-based copolymers such as styrene-acrylate copolymers and styrene-methacrylate copolymers are preferred.

[0172] [Polymerizable monomer]

[0173] As the polymerizable monomer used in the styrene-based copolymer, a radically polymerizable vinyl-based polymerizable monomer can be used. As the vinyl-based polymerizable monomer, a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer can be used.

[0174] Examples of the monofunctional polymerizable monomers include: styrene; styrene derivatives such as α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, p-butylstyrene, p-tert-butylstyrene, p-hexylstyrene, p-octylstyrene, p-nonylstyrene, p-decylstyrene, p-dodecylstyrene, p-methoxystyrene and p-phenylstyrene; acrylic polymerizable monomers such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate, ethyl acrylate, diethyl phosphate, ethyl acrylate, dibutyl phosphate, ethyl acrylate and 2-benzoyloxyethyl acrylate; methacrylic acid-based polymerizable monomers such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, diethyl phosphate, ethyl methacrylate and dibutyl phosphate, ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate and vinyl formate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; and vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropyl ketone.

[0175] Examples of the multifunctional polymerizable monomer include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 2,2′-bis(4-(acryloyloxy-diethoxy)phenyl)propane, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, alcohol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2'-bis(4-(methacryloyloxy-diethoxy)phenyl)propane, 2,2'-bis(4-(methacryloyloxy-polyethoxy)phenyl)propane, trimethylolpropane trimethacrylate, tetramethylolmethane tetramethacrylate, divinylbenzene, divinylnaphthalene and divinyl ether.

[0176] The above-mentioned monofunctional polymerizable monomers are used alone or in combination, or the above-mentioned monofunctional polymerizable monomers and polyfunctional polymerizable monomers are used in combination.

[0177] The polymerizable monomer used in addition to styrene is preferably a styrene derivative, such as an acrylic polymerizable monomer such as n-butyl acrylate or 2-ethylhexyl acrylate, or a methacrylic polymerizable monomer such as n-butyl methacrylate or 2-ethylhexyl methacrylate. This is because such a polymerizable monomer is excellent in strength and flexibility of a binder resin obtained by polymerizing the polymerizable monomer.

[0178] The polyester resin can be obtained by a reaction between a divalent or higher polycarboxylic acid and a polyol.

[0179] Examples of the polycarboxylic acid include the following compounds: dibasic acids such as succinic acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, malonic acid and dodecenylsuccinic acid, and anhydrides or lower alkyl esters thereof; and aliphatic unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid and citraconic acid.

[0180] Examples also include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, and anhydrides thereof or lower alkyl esters thereof. These polycarboxylic acids may be used alone or in combination thereof.

[0181] Examples of polyols may include the following compounds: alkylene glycols (ethylene glycol, 1,2-propylene glycol, and 1,3-propylene glycol); alkylene ether glycols (polyethylene glycol and polypropylene glycol); alicyclic diols (1,4-cyclohexanedimethanol); bisphenol (bisphenol A); and alkylene oxide (ethylene oxide and propylene oxide) adducts of alicyclic diols. The alkyl moieties of each of the alkylene glycols and the alkylene ether glycols may be linear or branched. Examples also include glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol. These polyols may be used alone or in combination.

[0182] For the purpose of adjusting the acid value and the hydroxyl value, a monobasic acid such as acetic acid or benzoic acid and a monohydric alcohol such as cyclohexanol or benzyl alcohol may also be used as necessary.

[0183] The production method of the polyester resin is not particularly limited, but, for example, an ester exchange method and a direct polycondensation method may be used alone or in combination thereof.

[0184] Next, the polyurethane resin is described. The polyurethane resin is a reaction product between a diol and a substance containing a diisocyanate group, and by adjusting the diol and the diisocyanate, a resin having various functionalities can be obtained.

[0185] Examples of the diisocyanate component include the following compounds: aromatic diisocyanates each having 6 or more and 20 or less carbon atoms (excluding carbon atoms in NCO groups, the same below); aliphatic diisocyanates each having 2 or more and 18 or less carbon atoms; alicyclic diisocyanates each having 4 or more and 15 or less carbon atoms; and modified products of these diisocyanates (modified products containing a carbamate group, a carbodiimide group, an allophanate group, a urea group, a biuret group, a uretdione group, a uretimine group, an isocyanurate group and an oxazolidinone group, hereinafter sometimes referred to as "modified diisocyanates"); and mixtures of two or more thereof.

[0186] Examples of the aromatic diisocyanate include the following compounds: m- and / or p-xylylene diisocyanate (XDI); and α,α,α′,α′-tetramethylxylene diisocyanate.

[0187] In addition, examples of the aliphatic diisocyanate include the following compounds: ethylene diisocyanate; tetramethylene diisocyanate; hexamethylene diisocyanate (HDI); and dodecamethylene diisocyanate.

[0188] In addition, examples of the alicyclic diisocyanate include the following compounds: isophorone diisocyanate (IPDI); dicyclohexylmethane-4,4′-diisocyanate; cyclohexylene diisocyanate; and methylcyclohexylene diisocyanate.

[0189] Among them, aromatic diisocyanates each having 6 to 15 carbon atoms, aliphatic diisocyanates each having 4 to 12 carbon atoms, and alicyclic diisocyanates each having 4 to 15 carbon atoms are preferred, and XDI, IPDI, and HDI are particularly preferred.

[0190] Furthermore, in addition to the diisocyanate component, a trifunctional or higher-functional isocyanate compound may be used.

[0191] As the diol component that can be used for the polyurethane resin, the same alcohols as those described above that can be used for the polyester resin can be used.

[0192] [Colorant]

[0193] The toner base particles may contain a colorant. Depending on the color of the toner, a known pigment or dye may be used as the colorant. In order to form a high-quality image by using the toner, the amount of the colorant is preferably 1 part by mass or more and 20 parts by mass or less, and more preferably 2 parts by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0194] The toner base particles may contain a black colorant. An example of a black colorant is carbon black. In addition, the black colorant may be a colorant toned to black by using a yellow colorant, a magenta colorant, and a cyan colorant. The toner base particles may contain a colorant such as a yellow colorant, a magenta colorant, or a cyan colorant.

[0195] For example, as a yellow colorant, one or more compounds selected from the group consisting of condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and arylamide compounds can be used respectively. CI Pigment Yellow (3, 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 191, or 194) classified by color index, naphthol yellow S, Hansa Yellow G, or CI Vat Yellow can be suitably used as a yellow colorant.

[0196] As the magenta colorant, one or more compounds selected from the group consisting of condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds can be used respectively. CI Pigment Red (2, 3, 5, 6, 7, 19, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221 or 254) classified by color index can be suitably used as the magenta colorant.

[0197] For example, as a cyan colorant, one or more compounds selected from the group consisting of: copper phthalocyanine compounds; anthraquinone compounds; and basic dye lake compounds can be used respectively. CI Pigment Blue (1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62 or 66), Phthalocyanine Blue, CI Vat Blue or CI Acid Blue classified by Color Index can be suitably used as a cyan colorant.

[0198] [Release agent]

[0199] The toner particles may contain a releasing agent.

[0200] Examples of the release agent include: waxes each containing a fatty acid ester as a main component, such as carnauba wax and montanic acid ester wax; waxes obtained by removing a part or all of the acid component from a fatty acid ester, such as deacidified carnauba wax; methyl ester compounds having a hydroxyl group obtained by hydrogenating vegetable oils and fats; saturated fatty acid monoesters, such as stearyl stearate and behenyl behenate; diesterification products of saturated aliphatic dicarboxylic acids and saturated aliphatic alcohols, such as behenyl sebacate, distearyl dodecanedioate, distearyl octadecanediol; diesterification products of saturated aliphatic diols and saturated fatty acids, such as nonanediol disbehenate and dodecanedioyl distearate; aliphatic hydrocarbon waxes, such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax; oxides of aliphatic hydrocarbon waxes such as polyethylene oxide wax or block copolymers thereof; waxes; saturated straight-chain fatty acids such as palmitic acid, stearic acid and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid and stearidonic acid; saturated alcohols such as stearyl alcohol, aralkyl alcohols, behenyl alcohol, carnauba alcohol, ceryl alcohol and myricol; polyols such as sorbitol; fatty acid amides such as linoleamide, oleamide and lauramide; saturated fatty acid bisamides such as methylene bisstearamide, ethylene bisdecylamide, ethylene bislauramide and hexamethylene bisstearamide ; unsaturated fatty acid amides, such as ethylenebisoleamide, hexamethylenebisoleamide, N,N′-dioleyl adipamide and N,N′-dioleyl sebacamide; aromatic bisamides, such as meta-xylene bisstearamide and N,N′-distearylisophthalic acid amide; fatty metal salts, such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate (commonly referred to as “metal soaps”); and long-chain alkyl alcohols or long-chain alkyl carboxylic acids, each having 12 or more carbon atoms.

[0201] The content of the releasing agent in the toner particles is preferably from 1.0% by mass to 30.0% by mass, and more preferably from 2.0% by mass to 25.0% by mass.

[0202] [Charge Control Agent Having Positive Chargeability and Charge Control Resin Having Positive Chargeability]

[0203] The toner preferably contains at least one selected from the group consisting of a charge control agent having positive chargeability and a charge control resin having positive chargeability.

[0204] When a charge control agent having positive chargeability or a charge control resin having positive chargeability is used and the addition amount thereof is adjusted, the charge control agent having positive chargeability or the charge control resin having positive chargeability also functions as an electron donating site, thereby obtaining a higher charge amount.

[0205] Examples of the charge control agent having positive chargeability include nigrosine dyes, quaternary ammonium salts, triaminotriphenylmethane compounds, and imidazole compounds.

[0206] Examples of charge control resins having positive chargeability include polyamine resins, copolymers containing quaternary ammonium groups, and copolymers containing quaternary ammonium salt groups. Among them, charge control resins having good dispersibility in toners are preferred, and copolymers containing quaternary ammonium salt groups (e.g., styrene acrylic resins containing quaternary ammonium salt groups) are more preferred.

[0207] In addition, the positive chargeability of the toner is easily affected by the surface of the toner particles, and therefore it is preferred that a charge control agent or a charge control resin having positive chargeability is present on the outermost surface of the toner particles.

[0208] For example, in a toner having a core-shell structure, it is preferred that a charge control agent or a charge control resin having positive chargeability is contained in a shell agent.

[0209] The charge control agent and / or charge control resin is contained in an amount of preferably 0.01 to 10 parts by mass, more preferably 0.03 to 8 parts by mass, relative to 100 parts by mass of the binder resin.

[0210] [External addition process]

[0211] In the external addition process, the external additive is attached to the surface of the toner base particles. As a result, toner particles containing the toner base particles and the external additive attached to the surface of the toner base particles are obtained. The method for attaching the external additive to the surface of the toner base particles is not particularly limited, but is, for example, a method involving stirring the toner base particles and the external additive using a mixer.

[0212] <Method for Separating and Recovering Alumina Particles in Toner>

[0213] 160g sucrose (manufactured by Kishida Chemical Co., Ltd.) is added to 100ml ion exchange water and dissolved therein under hot water heating to prepare sucrose concentrate. 31g sucrose concentrate and 6mL Contaminon N (a 10% aqueous solution of a neutral detergent with a pH of 7 for cleaning precision measuring instruments formed by nonionic surfactants, anionic surfactants and organic builders, manufactured by Wako Pure Chemical Industries, Ltd.) are placed in a centrifuge tube (capacity: 50mL). 1.0g toner is added to the mixture and the toner block is broken up with a spatula or the like. The centrifuge tube is vibrated for 20 minutes at 300 strokes / minute (spm) with an oscillator (AS-1N, sold by AS ONE Corporation). After vibration, the solution is transferred to a swing rotor glass tube (50mL) and separated for 30 minutes at 3,500rpm in a centrifuge (H-9R, manufactured by KOKUSAN Co., Ltd.).

[0214] Through the above operation, the toner particles and the external additive are separated. Visually identify that the toner particles and the aqueous solution are fully separated, and the separated toner particles and external additives are collected with a spatula or the like. When inorganic fine particles A and other external additives are mixed as external additives, the resulting product is separated by further centrifugal separation using the difference in particle size and specific gravity, thereby providing the target product. This operation is performed multiple times to ensure the required amount. After the collected toner particles and aluminum oxide particles are filtered through a decompression filter, they are then dried with a dryer for more than 1 hour to provide a sample for measurement. This operation is performed multiple times to ensure the required amount.

[0215] <Method for Determining Content of Alumina Particles in Toner>

[0216] The content of the aluminum oxide particles in the toner can be calculated by measuring the toner and the toner particles each from which the external additive has been removed by the above-mentioned method using X-ray fluorescence analysis (XRF).

[0217] A wavelength dispersive X-ray fluorescence analyzer "Axios" (manufactured by PANalytical) and the accompanying dedicated software "SuperQ Ver.4.0F" (manufactured by PANalytical) for setting measurement conditions and analyzing measurement data were used as the measurement device. Rh was used as the anode of the X-ray tube. The measurement atmosphere was set to vacuum. The measurement diameter (collimator mask diameter) was set to 27 mm, and the measurement time was set to 10 seconds. In addition, when measuring boron as a light element, a proportional counter (PC) was used to detect boron.

[0218] The pellets obtained by placing 4 g of the toner in a dedicated pressing aluminum ring, flattening the toner, and pressing the toner at 20 MPa for 60 seconds to a thickness of about 2 mm and a diameter of about 39 mm using a tablet molding compressor "BRE-32" (manufactured by Maekawa Testing Machine MFG, Co., LTD.) are used as measurement samples, and the counting rate intensity (unit: cps) of the Group 13 elements is measured.

[0219] In this case, the acceleration voltage and current value of the X-ray generating device were set to 32 kV and 125 mA, respectively.

[0220] [Electronic photography equipment]

[0221] The electronic photographic apparatus of the present invention includes: an electronic photographic photosensitive member; a charging unit that charges the surface of the electronic photographic photosensitive member; an exposure unit that irradiates the charged surface of the electronic photographic photosensitive member with light to form an electrostatic latent image on the surface of the electronic photographic photosensitive member; a developing unit that includes a colorant and develops the electrostatic latent image formed on the surface of the electronic photographic photosensitive member with the colorant to form a colorant image on the surface of the electronic photographic photosensitive member; and a transfer unit that transfers the colorant image from the surface of the electronic photographic photosensitive member to a transfer material.

[0222] The present invention is described in detail below based on the illustrated embodiments.

[0223] Reference below Figure 5 A tandem type color electrophotographic apparatus is described as an example. Figure 5 is a cross-sectional view for explaining one example of an electrophotographic apparatus. Figure 5 The illustrated electrophotographic apparatus 100 includes image forming units 40a, 40b, 40c and 40d, a transfer belt 50 and a fixing device 54. When no distinction is required, each image forming unit 40a, 40b, 40c, 40d is sometimes referred to as an "image forming unit 40" below. The image forming unit 40 includes an image bearing member 30, a charging device 42, an exposure device 44, a developing device 46 and a transfer device 48. The image bearing member 30 is a photosensitive member (specifically, a single-layer photosensitive member 1). In addition, a recording medium P is located at the lower part of the electrophotographic apparatus. The image bearing member 30 is arranged at the center position of the image forming unit 40. The image bearing member 30 is arranged to extend in the direction of the arrow ( Figure 5 The charging device 42, the exposure device 44, the developing device 46, and the transfer device 48 are arranged around the image bearing member 30 in the stated order from the upstream side in the rotation direction of the image bearing member 30.

[0224] A toner image of a plurality of colors (for example, four colors of black, cyan, magenta, and yellow) is sequentially superimposed on a recording medium P on a transfer belt 50 through each of the image forming units 40a to 40d. The charging device 42 charges the surface (for example, the peripheral surface) of the image bearing member 30 with positive polarity. When the image bearing member 30 is a single-layer type photosensitive member 1, the surface of the image bearing member 30 is charged with positive polarity. The charging device 42 is, for example, a charging roller. The exposure device 44 irradiates the charged surface of the image bearing member 30 with exposure light. That is, the exposure device 44 exposes the charged surface of the image bearing member 30. As a result, an electrostatic latent image is formed on the surface of the image bearing member 30. The electrostatic latent image is formed based on image data input to the electrophotographic apparatus 100.

[0225] The developing device 46 supplies toner to the surface of the image bearing member 30, thereby developing the electrostatic latent image into a toner image. The developing device 46 (for example, the surface of the developing device 46, more specifically, the peripheral surface of the developing device 46) is in contact with the surface of the image bearing member 30. That is, the electronic photographic apparatus 100 adopts a contact development system. The developing device 46 is, for example, a developing roller. When the developer is a single-component developer, the developing device 46 supplies a toner as a single-component developer to the electrostatic latent image formed on the image bearing member 30. When the developer is a two-component developer, the developing device 46 supplies a toner in the two-component developer and a toner in a carrier to the electrostatic latent image formed on the image bearing member 30. In this way, the image bearing member 30 carries the toner image. The transfer belt 50 conveys the recording medium P to a position between the image bearing member 30 and the transfer device 48.

[0226] The transfer belt 50 is an endless belt. The transfer belt 50 is extended in the direction of the arrow ( Figure 5The transfer device 48 is configured in a rotatable manner (clockwise direction in the figure). The transfer device 48 transfers the colorant image developed by the developing device 46 from the surface of the image bearing member 30 to the transfer object member. The transfer object member is the recording medium P. When the colorant image is transferred, the image bearing member 30 is in contact with the recording medium P. That is, the electronic photographic apparatus 100 adopts a direct transfer system. The transfer device 48 is, for example, a transfer roller. The recording medium P having the colorant image transferred thereto by the transfer device 48 is conveyed to the fixing device 54 by the transfer belt 50. The fixing device 54 is, for example, a heating roller and / or a pressure roller. The unfixed colorant image transferred by the transfer device 48 is heated and / or pressurized by the fixing device 54. The toner image is fixed to the recording medium P by heating and / or pressurizing. As a result, an image is formed on the recording medium P. An example of an electronic photographic apparatus has been described above, but the electronic photographic apparatus is not limited to the electronic photographic apparatus 100 described above. The above-mentioned electrophotographic apparatus 100 is a color electrophotographic apparatus, but the electrophotographic apparatus may also be a monochrome electrophotographic apparatus. In this case, it is only necessary that the electrophotographic apparatus includes, for example, only one image forming unit.

[0227] In addition, the electronic photographic device 100 described above adopts a series system, but the electronic photographic device may also adopt, for example, a rotary system. The charging device 42 is described by taking a charging roller as an example, but the charging device may also be a charging device other than a charging roller (for example, a scorotron charger, a charging brush, or a corotron charger). The electronic photographic device 100 described above adopts a contact development system, but the electronic photographic device may also adopt a non-contact development system. The electronic photographic device 100 described above adopts a direct transfer system, but the electronic photographic device may also adopt an intermediate transfer system. When the electronic photographic device adopts an intermediate transfer system, the transfer object member corresponds to the intermediate transfer belt. In the electronic photographic device, the image forming unit 40 described above does not include a cleaning member, but the image forming unit may further include a cleaning member (for example, a cleaning blade). The image forming unit 40 described above does not have a charge elimination device, but the image forming unit may further include a charge elimination device.

[0228] [Processing cartridge]

[0229] The processing box of the present invention is the following processing box, which includes: an electronic photographic photosensitive member; and a developing unit, which includes a colorant and is constructed to use the colorant to form a colorant image on the surface of the electronic photographic photosensitive member, the processing box integrally supports the electronic photographic photosensitive member and the developing unit, and is detachably mounted to the main body of the electronic photographic device, wherein the electronic photographic photosensitive member includes a single-layer photosensitive layer containing a charge generating material, a hole transporting material, an electron transporting material and a binder resin, wherein the photosensitive layer contains a polyarylate resin having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2) as a binder resin, wherein the colorant is a colorant containing colorant particles, wherein the colorant particles each contain a colorant base particle and an external additive attached to the surface of the colorant base particle, and wherein the external additive contains at least aluminum oxide particles.

[0230]

[0231] The electrophotographic photosensitive member and the toner are as described above, and thus description thereof is omitted.

[0232] Next, continue to refer to Figure 5 , describes an example of a processing box according to an embodiment of the present invention. The processing box corresponds to each of the image forming units 40a to 40d. The processing box includes an image bearing member 30. The image bearing member 30 is a photosensitive member of the first embodiment. In addition to the image bearing member 30, the processing box also includes at least one selected from the group consisting of: a charging device 42, an exposure device 44, a developing device 46 and a transfer device 48. The processing box may also include a cleaning member (not shown) and a charge eliminating device (not shown). The processing box is designed to be detachably mounted to the electronic photographic device 100. Therefore, the processing box is easy to handle, and when the sensitivity characteristics of the image bearing member 30, etc., are deteriorated, it can be easily and quickly replaced together with the image bearing member 30. Reference has been made above Figure 5 A process cartridge including a photosensitive member is described.

[0233] [Example]

[0234] The present invention is described in more detail below by examples and comparative examples. Without departing from the scope of the present invention, the present invention is by no means restricted by the following examples. In the description of the following examples, unless otherwise indicated, the term "part" is by mass.

[0235] <Production of polyarylate resin (PAR)>

[0236] [Synthesis of resin (PAR-1)]

[0237] A three-necked flask including a thermometer, a three-way stopcock and a dropping funnel was used as a reaction vessel. Compound (BP-2) (41.0 mmol) as a monomer, 2,6-dimethylphenol (DMP) (0.213 mmol) as a terminal terminator, sodium hydroxide (98 mmol) and benzyltributylammonium chloride (0.384 mmol) were loaded into the reaction vessel. The air in the reaction vessel was replaced by argon. Water (300 mL) was added to the contents of the reaction vessel. The contents in the reaction vessel were stirred at 50 ° C for 1 hour. The contents in the reaction vessel were cooled to 10 ° C to provide an alkaline aqueous solution A.

[0238] Next, dicarboxylic acid dichloride (32.0 mmol) of compound (DC-1) as a monomer was dissolved in chloroform (150 mL). As a result, chloroform solution B was obtained.

[0239] Chloroform solution B was slowly dripped into alkaline aqueous solution A over 110 minutes by using a dropping funnel. While the temperature (liquid temperature) of the contents in the reaction vessel was adjusted to 15 ± 5 ° C, the contents in the reaction vessel were stirred for 4 hours to allow the polymerization reaction to proceed. The upper layer (water layer) of the contents in the reaction vessel was removed by decantation. Thus, an organic layer was obtained. Next, ion exchange water (400mL) was loaded into a conical flask. The obtained organic layer was further added to a conical flask. Chloroform (400mL) and acetic acid (2mL) were further added to a conical flask. The contents in the conical flask were stirred at room temperature (25 ° C) for 30 minutes. The upper layer (water layer) of the contents in the conical flask was removed by decantation. Thus, an organic layer was obtained. The obtained organic layer was washed with ion exchange water (1L) by using a separatory funnel. Washing with ion exchange water was repeated 5 times. Thus, a water-washed organic layer was obtained. Next, the water-washed organic layer was filtered to provide a filtrate. The obtained filtrate was slowly dripped into methanol (1L) to provide a precipitate. The precipitate was taken out by filtration. The precipitate thus taken out was vacuum dried at a temperature of 70° C. for 12 hours. As a result, a resin (PAR-1) having a viscosity average molecular weight of 35,000 was obtained.

[0240] [Synthesis of resin (PAR-2)]

[0241] A three-necked flask including a thermometer, a three-way stopcock and a dropping funnel was used as a reaction vessel. Compound (BP-2) (28.7mmol) as a monomer, compound (BP-5) (12.3mmol) as a monomer, 2,6-dimethylphenol (DMP) (0.413mmol) as a terminal terminator, sodium hydroxide (98mmol) and benzyltributylammonium chloride (0.384mmol) were loaded into the reaction vessel. The air in the reaction vessel was replaced by argon. Water (300mL) was added to the contents of the reaction vessel. The contents in the reaction vessel were stirred at 50°C for 1 hour. The contents in the reaction vessel were cooled to 10°C to provide an alkaline aqueous solution A.

[0242] Next, dicarboxylic acid dichloride (20.8 mmol) of compound (DC-1) as a monomer and dicarboxylic acid dichloride (11.2 mmol) of compound (DC-4) as a monomer were dissolved in chloroform (150 mL). As a result, chloroform solution B was obtained.

[0243] Chloroform solution B was slowly dripped into alkaline aqueous solution A over 110 minutes by using a dropping funnel. While the temperature (liquid temperature) of the contents in the reaction vessel was adjusted to 15 ± 5 ° C, the contents in the reaction vessel were stirred for 4 hours to allow the polymerization reaction to proceed. The upper layer (water layer) of the contents in the reaction vessel was removed by decantation. Thus, an organic layer was obtained. Next, ion exchange water (400mL) was loaded into a conical flask. The obtained organic layer was further added to a conical flask. Chloroform (400mL) and acetic acid (2mL) were further added to a conical flask. The contents in the conical flask were stirred at room temperature (25 ° C) for 30 minutes. The upper layer (water layer) of the contents in the conical flask was removed by decantation. Thus, an organic layer was obtained. The obtained organic layer was washed with ion exchange water (1L) by using a separatory funnel. Washing with ion exchange water was repeated 5 times. Thus, a water-washed organic layer was obtained. Next, the water-washed organic layer was filtered to provide a filtrate. The obtained filtrate was slowly dripped into methanol (1L) to provide a precipitate. The precipitate was taken out by filtration. The precipitate thus taken out was vacuum dried at a temperature of 70° C. for 12 hours. As a result, a resin (PAR-2) having a viscosity average molecular weight of 55,000 was obtained.

[0244] [Synthesis of resins (PAR-3) to (PAR-14)]

[0245] The synthesis was performed by the same method as that of the resin (PAR-2) having a viscosity average molecular weight of 55,000 except that the ratio of bisphenol and dicarboxylic acid and the terminal terminator were changed. Thus, resins (PAR) having the viscosity average molecular weights shown in Table 1 were obtained. As the input amount of the terminal terminator became smaller, the viscosity average molecular weight of each resin (PAR) became higher.

[0246] Table 1

[0247]

[0248] The numerical values ​​of bisphenols in Table 1 each represent the molar fraction of bisphenol relative to the total molar number of two bisphenols. In addition, the numerical values ​​of dicarboxylic acids each represent the molar fraction of dicarboxylic acids relative to the total molar number of two dicarboxylic acids. In addition, "PFH" represents 1H,1H-perfluoro-1-heptanol. In addition, the molecular weight represents the viscosity average molecular weight.

[0249] <Manufacture of Electrophotographic Photosensitive Member>

[0250] [Manufacture of Photosensitive Member 1]

[0251] 2.0 parts by mass of Y-type oxytitanium phthalocyanine (CGM-1) as a charge generating material, 70.0 parts by mass of a hole transporting material (H-11), 50.0 parts by mass of an electron transporting material (E-4), 100.0 parts by mass of a polyarylate resin (PAR-1) as a binder resin, 14.0 parts by mass of an additive (T-1) and 500.0 parts by mass of tetrahydrofuran as a solvent were mixed with a rod-shaped sonic oscillator for 20 minutes to provide a dispersion. The dispersion was filtered through a filter having an opening of 5 μm to provide a photosensitive layer coating liquid. The photosensitive layer coating liquid was applied to a conductive support (aluminum drum-shaped support) by a dip coating method and dried with hot air at 120° C. for 50 minutes. Thus, a photosensitive layer (thickness: 30 μm) was formed on the conductive support to provide a photosensitive member 1.

[0252] (Resin Component Analysis of Photosensitive Member 1)

[0253] By recovering the polymer component from the obtained photosensitive member in deuterated chloroform 1 H-NMR spectroscopy 1 H-NMR spectrum. 1 The H-NMR spectrum has peaks at 8.22±0.02ppm, 7.18±0.02ppm, 7.16±0.02ppm, 7.10±0.02ppm, 7.06±0.02ppm and 7.04±0.02ppm. Therefore, it was determined that the photosensitive member has structural units represented by formula (1) and formula (2). In addition, based on the integral ratio of the above peaks, the ratio of the amount of formula (1) and formula (2) is 1:1 as shown in Table 1.

[0254] [Manufacture of Photosensitive Members 2 to 23]

[0255] Photosensitive members 2 to 32 were respectively manufactured by the same method as the manufacture of photosensitive member 1, except that different kinds of charge generating materials, additives, hole transport materials, electron transport materials and binder resins were used. The kinds of charge generating materials, additives, hole transport materials, electron transport materials and binder resins used are shown in Table 2. In addition, for each photosensitive member, the ratio of each mass was not changed. The manufacturing example of the photosensitive member is shown in Table 2. The thickness of the photosensitive layer in photosensitive member 5 was 50 μm. In addition, the thickness of the photosensitive layer of each of the other photosensitive members 2 to 4 and 6 to 32 was 30 μm. In Table 2, "CGM" represents a charge generating material, "HTM" represents a hole transport material, and "ETM" represents an electron transport material.

[0256] (Resin Component Analysis of Photosensitive Member 8)

[0257] By recovering the polymer component from the obtained photosensitive member in deuterated chloroform 1 H-NMR spectroscopy 1 H-NMR spectrum. 1 The H-NMR spectrum has peaks at 8.22±0.02ppm, 7.18±0.02ppm, 7.16±0.02ppm, 7.10±0.02ppm, 7.06±0.02ppm, 7.04±0.02ppm, 2.28±0.02ppm, 2.20±0.02ppm, 1.59±0.02ppm and 1.54±0.02ppm. Therefore, it is determined that the photosensitive member has structural units represented by formula (1), formula (2), formula (4) and formula (5). In addition, based on the integral ratio of the above peaks, the ratio of the amount of substances of formula (1), formula (2), formula (4) and formula (5) is shown in Table 1.

[0258] [Manufacturing of Photosensitive Member 33]

[0259] The photosensitive member 33 was produced by the same method as the photosensitive member 8 except that 60 parts by mass of (PAR-08) and 40 parts by mass of (PAR-14) were used as the polyarylate resin serving as the binder resin.

[0260] [Manufacturing of Photosensitive Member 34]

[0261] The photosensitive member 34 was produced by the same method as the photosensitive member 8 except that 40 parts by mass (PAR-08) and 60 parts by mass (PAR-14) were used as the polyarylate resin serving as the binder resin.

[0262] Table 2

[0263]

[0264] <Toner Production Example>

[0265] <Preparation of polymer A0>

[0266] Under a nitrogen atmosphere, the following materials were charged into a reaction vessel including a reflux condenser, a stirrer, a thermometer and a nitrogen inlet tube.

[0267]

[0268] (Polymerization initiator, manufactured by NOF Corporation: PERBUTYL PV)

[0269] While stirring at 200rpm, the material in the reaction vessel is heated to 70°C to allow the polymerization reaction to proceed for 12 hours. Thus, a solution in which the polymer of the monomer composition is dissolved in toluene is obtained. Subsequently, the solution is lowered to a temperature of 25°C, and then the solution is charged into 1,000.0 parts of methanol while stirring. Thus, methanol insolubles are precipitated. The obtained methanol insolubles are separated by filtration. The resultant is further washed with methanol and then vacuum dried at 40°C for 24 hours to provide polymer A0. The weight average molecular weight (Mw) of polymer A0 is 68,400, the acid value is 0.0mgKOH / g, and the melting point is 62°C.

[0270] As a result of analysis of the polymer A0 by NMR, it was found that the polymer contained 28.9 mol% of a monomer unit derived from behenyl acrylate, 53.8 mol% of a monomer unit derived from methacrylonitrile, and 17.3 mol% of a monomer unit derived from styrene.

[0271] <Preparation of Amorphous Resin>

[0272] The following raw materials were charged into a heated and dried two-necked flask while introducing nitrogen gas thereinto.

[0273]

[0274]

[0275] The interior of the system was replaced with nitrogen by a decompression operation, followed by stirring at 215°C for 5 hours. Thereafter, while continuing to stir, the temperature in the system was gradually raised to 230°C under reduced pressure and further maintained for 2 hours. When the mixture entered a viscous state, the reaction was terminated by air cooling. Thus, an amorphous resin as an amorphous polyester was synthesized. The number average molecular weight (Mn) of the amorphous resin was 5,200, the weight average molecular weight (Mw) was 23,000, and the glass transition temperature (Tg) was 55°C.

[0276] [Manufacturing of toner by suspension polymerization]

[0277] (Manufacturing of Toner Base Particles 1)

[0278]

[0279] A mixture formed of the above materials was prepared. The mixture was charged into an attritor (manufactured by Nippon Coke & Engineering. Co., Ltd.), and dispersed with zirconia beads each having a diameter of 5 mm at 200 rpm for 2 hours to provide a raw material dispersion.

[0280] At the same time, an aqueous solution obtained by dissolving 6.2 parts of sodium hydroxide (alkali metal hydroxide) in 50 parts of ion exchange water was slowly added to an aqueous solution obtained by dissolving 10.2 parts of magnesium chloride (water-soluble multivalent metal salt) in 250 parts of ion exchange water at room temperature under stirring to prepare a magnesium hydroxide colloid (poorly water-soluble metal hydroxide colloid) dispersion.

[0281] The above polymerizable monomer composition was charged into the magnesium hydroxide colloidal dispersion at room temperature and then stirred. 8.0 parts of tert-butyl peroxypivalate (PERBUTYL PV, manufactured by NOF) were charged into the resultant as a polymerization initiator, and then dispersed for 10 minutes by high-speed shearing and stirring at a rotation speed of 15,000 rpm using an in-line emulsifying disperser (product name: MILDER, manufactured by Pacific Machinery & Engineering Co., Ltd.). Thus, droplets of the polymerizable monomer composition were formed.

[0282] The obtained granulation liquid was transferred to a reaction vessel including a reflux condenser, a stirrer, a thermometer and a nitrogen introduction tube, and the granulation liquid was raised to a temperature of 70°C while stirring at 150 rpm under a nitrogen atmosphere. While maintaining the temperature at 70°C, a polymerization reaction was performed at 150 rpm for 10 hours. Thereafter, the reflux condenser was removed from the reaction vessel, and the reaction liquid was raised to a temperature of 95°C. Then, while maintaining the temperature at 95°C, toluene was removed by stirring the reaction liquid at 150 rpm for 5 hours. Thus, a toner base particle dispersion was obtained.

[0283] While stirring the obtained dispersion of toner base particles at room temperature, sulfuric acid was added dropwise thereto to perform acid washing until the pH of the liquid reached 6.5 or less. Then, filtration separation was performed, and the obtained solid component was re-pulped by adding 500 parts of ion exchange water thereto. The water washing treatment (washing, filtration, dehydration) was repeated several times. Then, filtration separation was performed, and the obtained solid component was placed in a container of a dryer and dried at 40° C. for 24 hours to provide toner base particles 1 each containing polymer A1 of the monomer composition.

[0284] Furthermore, a polymer A1′ was obtained in the same manner as above except that the pigment blue 15:3, the charge control resin, and the releasing agent were not used in the above-mentioned method for producing the toner base particles 1.

[0285] The weight average molecular weight (Mw) of polymer A1' was 57,000 and the melting point was 62°C.

[0286] As a result of analyzing the polymer A1 by NMR, it was found that the polymer contained 28.87 mol% of monomer units derived from behenyl acrylate, 53.79 mol% of monomer units derived from methacrylonitrile, 17.33 mol% of monomer units derived from styrene, and 8.2×10 -3 mol% of macromonomer.

[0287] Polymer A1 and polymer A1' were produced in the same manner and therefore were confirmed to have equivalent physical properties.

[0288] (Preparation of Toner 1)

[0289] Toner Base Particles 1 were externally added. By using a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), 0.7 parts of alumina particles 1 (alumina particles obtained by calcining aluminum hydroxide and then pulverizing the resultant with a pulverizer, number average particle diameter: 150 nm) and 1.0 parts of silica fine particles (silica fine particles having a primary particle number average particle diameter of 55 nm subjected to hydrophobization treatment with amino-modified silicone oil) were dry-mixed with 100.0 parts of Toner Base Particles 1 for 5 minutes to provide Toner 1 (TA-1) containing Toner Particles 1.

[0290] <Manufacturing Example of Toner 2>

[0291] Toner 2 (TA-2) was obtained in the same manner as Toner 1 above, except that Alumina Particles 1 were changed to Alumina Particles 2 (alumina particles obtained by calcining aluminum hydroxide and then pulverizing the resultant with a pulverizer, number average particle size: 250 nm).

[0292] <Production Example of Toner 3>

[0293] Toner 3 (TA-3) was obtained in the same manner as Toner 1 above except that Alumina Particles 1 were changed to Alumina Particles 3 (alumina particles obtained by calcining aluminum hydroxide and then pulverizing the resultant with a pulverizer, number average particle size: 450 nm).

[0294] <Production Example of Toner 4>

[0295] [Manufacturing of toner by pulverization method]

[0296]

[0297] (Quaternary ammonium salt, manufactured by Orient Chemical Industries Co., Ltd., "BONTRON P-51")

[0298] The above materials were pre-mixed with an FM mixer (manufactured by Nippon Coke & Engineering Co., Ltd.), and the mixture was then melt-kneaded with a twin-screw kneading extruder (Model PCM-30, manufactured by Ikegai Ironworks Corp.).

[0299] The obtained kneaded product was cooled and coarsely pulverized with a hammer mill and then pulverized with a mechanical pulverizer (T-250, manufactured by Turbo Kogyo Co., Ltd.) The obtained finely pulverized powder was classified using a multi-classifier utilizing the Coanda effect to provide toner core particles having a weight average particle size (D4) of 7.0 μm.

[0300] At the same time, 300 mL of ion exchange water was placed in a 1 L three-necked flask including a thermometer and a stirring blade, and the temperature in the flask was then maintained at 30° C. with a water bath. Then, dilute hydrochloric acid was added to the flask to adjust the pH of the aqueous medium in the flask to 4. After the pH adjustment, 2 mL of an aqueous solution of an initial polymer of hexamethylolmelamine ("Mirbane Resin SM-607", manufactured by Showa Denko KK, solid content concentration: 80% by mass) was added to the flask as a raw material for the shell layer. Then, the contents in the flask were stirred so that the raw material for the shell layer was dissolved in the aqueous medium. Thus, an aqueous solution of the raw material for the shell layer was obtained.

[0301] 300 g of the above-mentioned toner core particles were added to a three-necked flask containing the above-mentioned aqueous solution, and the contents in the flask were stirred at a speed of 200 rpm for 1 hour. Then, 300 mL of ion exchange water was added thereto, and while stirring at 100 rpm, the temperature in the flask was raised to 70° C. at a speed of 1° C. / min. After the temperature was raised, the contents in the flask were continuously stirred at 70° C. and 100 rpm for 2 hours. Thereafter, the pH of the contents in the flask was adjusted to 7 by adding sodium hydroxide. Then, the contents in the flask were cooled to normal temperature to provide a dispersion containing toner base particles.

[0302] The wet cake-like toner base particles were filtered out from the dispersion containing the toner base particles using a Buchner funnel. The wet cake-like toner base particles were washed by dispersing the toner base particles in ion exchange water. Then, the toner base particles were dried by hot air drying to provide toner particles 4. Toner particles 4 were subjected to the same external addition as in the manufacturing example of toner 1 to provide toner 4 (TA-4).

[0303] <Production Example of Toner 5>

[0304] Toner 5 (TA-5) was obtained in the same manner as in the above-mentioned Toner 1 except that the amount of the aluminum oxide particles 1 was changed to 0.1 parts.

[0305] <Production Example of Toner 6>

[0306] Toner 6 (TA-6) was obtained in the same manner as in the above-mentioned Toner 1 except that the amount of the aluminum oxide particles 1 was changed to 3.0 parts.

[0307] <Production Example of Toner 7>

[0308] Toner 7 (TA-7) was obtained in the same manner as in Toner 1 except that Alumina Particles 1 were changed to Alumina Particles 4 (alumina particles obtained by calcining aluminum hydroxide and then pulverizing the resultant with a pulverizer, number average particle diameter: 60 nm).

[0309] <Production Example of Toner 8>

[0310] Toner 8 (TA-8) was obtained in the same manner as in the above-mentioned Toner 1 except that 0.3 parts of commercially available strontium titanate (manufactured by Titan Kogyo, Ltd., number average particle diameter: 110 nm) was further added as an external additive.

[0311] <Production Example of Toner 9>

[0312] Toner 9 (TA-9) was obtained in the same manner as in the above-mentioned Toner 8 except that 0.5 parts of polytetrafluoroethylene (L170JE, manufactured by AGC Inc.) was further added as an external additive.

[0313] <Evaluation>

[0314] The photosensitive member (single-layer type photosensitive member) and the toner were respectively evaluated for positive chargeability by the following method. The photosensitive member was mounted to an evaluation machine. A modified machine of an electrophotographic apparatus ("MFC-9840-CDW", manufactured by Brother Industries, Ltd.) was used as the evaluation machine.

[0315] [Evaluation of Positive Charging Property]

[0316] The toner on the photosensitive member is attracted and collected with a metal cylindrical tube and a cylindrical filter, and the triboelectric charge amount of the toner and the toner bearing amount are calculated. Figure 6 As shown, the triboelectric charge amount of toner and the toner bearing amount on the photosensitive member were measured using a Faraday cage.

[0317] By using a Faraday cage 200 (the Faraday cage 200 includes an inner cylinder 201 and an outer cylinder 202 as inner and outer double cylinders in which metal cylinders with different axial diameters are coaxially arranged with each other and also includes a filter 203 for taking out the toner in the inner cylinder 201), the toner on the photosensitive member is attracted by air. In the Faraday cage 200, the inner cylinder 201 and the outer cylinder 202 are insulated from each other by an insulating member 204. When the toner is sucked into the filter, electrostatic induction is caused by the charge amount Q of the toner. When a charged body with the charge amount Q is placed in the inner cylinder, the situation becomes as if a metal cylinder with the charge amount Q exists by electrostatic induction. The induced charge amount is measured with an electrometer (Keithley 6517A, manufactured by Keithley Instruments, Inc.), and the charge amount per unit mass (Q / M) obtained by dividing the charge amount Q (mC) by the toner mass M (kg) in the inner cylinder is used as the friction charge amount of the toner.

[0318] In addition, by measuring the suction area S (cm 2 ) and divide the toner mass M by the attraction area S (cm 2 ) to determine the toner carrying amount per unit area.

[0319] In the above-mentioned electrophotographic apparatus, before the toner layer formed on the photosensitive member is transferred onto the intermediate transfer member, the rotation of the photosensitive member is stopped, and the measurement is performed by directly sucking the toner image on the photosensitive member with air.

[0320] Toner loading (mg / cm 2 )=M / S

[0321] Triboelectric charge of toner (mC / kg) = Q / M

[0322] In the above electrophotographic apparatus, the toner bearing amount on the photosensitive member was adjusted to 0.35 mg / cm 2 , and the toner is attracted and collected by the above-mentioned metal cylindrical tube and the cylindrical filter. Then, the charge amount Q stored in the capacitor by the metal cylindrical tube and the mass M of the collected toner are measured, and the charge amount Q / M (mC / kg) per unit mass is calculated to determine the charge amount Q / M (mC / kg) per unit mass on the photosensitive member. The charge amount per unit mass is adopted as the toner charge amount for evaluating the positive chargeability.

[0323] The evaluation results are shown in Table 3.

[0324] Table 3

[0325] Toner Photosensitive member Toner charge Q / M [mC / Kg] Example 1 TA-1 Photosensitive member 1 41.8 Example 2 TA-1 Photosensitive member 2 43.6 Example 3 TA-1 Photosensitive member 3 41.8 Example 4 TA-1 Photosensitive member 4 42.6 Example 5 TA-1 Photosensitive member 5 43.4 Example 6 TA-1 Photosensitive member 6 42.5 Example 7 TA-1 Photosensitive member 7 42.7 Example 8 TA-1 Photosensitive member 8 44.5 Example 9 TA-1 Photosensitive member 9 42.5 Example 10 TA-1 Photosensitive member 10 42.9 Embodiment 11 TA-1 Photosensitive member 11 41.6 Example 12 TA-2 Photosensitive member 8 43.6 Example 13 TA-3 Photosensitive member 8 43.8 Embodiment 14 TA-4 Photosensitive member 8 45.2 Embodiment 15 TA-5 Photosensitive member 8 41.5 Example 16 TA-6 Photosensitive member 8 42.8 Embodiment 17 TA-7 Photosensitive member 8 42.5 Embodiment 18 TA-8 Photosensitive member 8 45.5 Embodiment 19 TA-9 Photosensitive member 8 45.6 Embodiment 20 TA-1 Photosensitive member 24 44.1 Embodiment 21 TA-1 Photosensitive member 25 43.9 Embodiment 22 TA-1 Photosensitive member 26 40.9 Embodiment 23 TA-1 Photosensitive member 27 44.2 Embodiment 24 TA-1 Photosensitive member 28 44.0 Embodiment 25 TA-1 Photosensitive member 29 41.3 Embodiment 26 TA-1 Photosensitive member 30 44.9 Embodiment 27 TA-1 Photosensitive member 31 44.7 Embodiment 28 TA-1 Photosensitive member 32 41.5 Embodiment 29 TA-1 Photosensitive member 33 40.8 Embodiment 30 TA-1 Photosensitive member 34 40.1 Comparative Example 1 TA-1 Photosensitive member 21 35.5 Comparative Example 2 TA-1 Photosensitive member 22 36.4 Comparative Example 3 TA-1 Photosensitive member 23 33.5 Comparative Example 4 TA-4 Photosensitive member 21 37.1 Comparative Example 5 TA-4 Photosensitive member 22 37.5 Comparative Example 6 TA-4 Photosensitive member 23 35.2

[0326] In each of Examples 1 to 19 using the photosensitive member containing the polyarylate resin and the toner according to the present invention, a decrease in the toner charge amount was suppressed.

[0327] At the same time, in each comparative example, the toner charge amount is reduced.

[0328] According to the present invention, a highly durable electrophotographic apparatus excellent in positive charging property can be provided in an electrophotographic apparatus using aluminum oxide as a toner external additive.

[0329] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. An electronic photographic device comprising: Electrophotographic photosensitive member; a charging unit configured to charge a surface of the electrophotographic photosensitive member; an exposure unit configured to irradiate the charged surface of the electrophotographic photosensitive member with light to form an electrostatic latent image on the surface of the electrophotographic photosensitive member; a developing unit including a toner and configured to develop the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with the toner, thereby forming a toner image on the surface of the electrophotographic photosensitive member; and a transfer unit configured to transfer the toner image from the surface of the electrophotographic photosensitive member to a transfer material, wherein the electrophotographic photosensitive member comprises a single-layer type photosensitive layer comprising a charge generating material, a hole transporting material, an electron transporting material and a binder resin, wherein the photosensitive layer contains, as the binder resin, a polyarylate resin having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), wherein the toner is a toner comprising toner particles, wherein the toner particles each include a toner base particle and an external additive attached to the surface of the toner base particle, and wherein the external additive comprises at least aluminum oxide particles, 2. The electrophotographic apparatus according to claim 1, wherein the photosensitive layer further comprises, as the binder resin, a polyarylate resin having a structural unit represented by the following formula (3) and a structural unit represented by the following formula (4):

3. The electrophotographic apparatus according to claim 1, wherein a ratio of the number of moles of the structural unit represented by the formula (1) relative to the total number of moles of the structural unit derived from the dicarboxylic acid used to form the polyarylate resin is 0.50 or more.

4. The electrophotographic apparatus according to claim 2, wherein the polyarylate resin has a structural unit represented by the formula (1), a structural unit represented by the formula (2), a structural unit represented by the formula (3) and a structural unit represented by the formula (4), and in, When the number of moles of the structural unit represented by the formula (1) in the total number of moles of the structural unit represented by the formula (1) and the number of moles of the structural unit represented by the formula (3) is represented by M1, the number of moles of the structural unit represented by the formula (2) in the total number of moles of the structural unit represented by the formula (2) and the number of moles of the structural unit represented by the formula (4) is represented by M2, the number of moles of the structural unit represented by the formula (3) in the total number of moles of the structural unit represented by the formula (1) and the number of moles of the structural unit represented by the formula (3) is represented by M3, and the number of moles of the structural unit represented by the formula (4) in the total number of moles of the structural unit represented by the formula (2) and the number of moles of the structural unit represented by the formula (4) is represented by M4, 0.30≤M3 / (M1+M3)<0.7 and 0<M2 / (M2+M4)<0.5 are satisfied. 5 . The electrophotographic apparatus according to claim 1 , wherein a ratio of the mass of the polyarylate resin to the mass of the binder resin is 50% by mass or more.

6. The electrophotographic apparatus according to claim 1, wherein the toner base particles each contain a binder resin, and The aluminum oxide particles as the external additive are contained in an amount of 0.1 parts by mass or more and 3.0 parts by mass or less relative to 100 parts by mass of the toner base particles. 7 . The electrophotographic apparatus according to claim 1 , wherein the number average value of the major diameter of the aluminum oxide particles is 60 nm or more and 450 nm or less. 8 . The electrophotographic apparatus according to claim 1 , wherein the external additive comprises strontium titanate particles. 9 . The electrophotographic apparatus according to claim 1 , wherein the external additive comprises fluorine-based resin particles.

10. The electrophotographic apparatus according to claim 1, wherein the electron transport material comprises a compound represented by the following formula (10), a compound represented by the following formula (11), a compound represented by the following formula (12), a compound represented by the following formula (13), a compound represented by the following formula (14), a compound represented by the following formula (15), or a compound represented by the following formula (16): Wherein Q in formula (10) 1 and Q 2 , Q in the formula (11) 11 , Q 12 and Q 13 , Q in the formula (12) 21 , Q 22 , Q 23 and Q 24 , Q in the formula (13) 31 and Q 32 , Q in the formula (14) 41 , Q 42 , Q 43 and Q 44 , Q in the formula (15) 51 , Q 52 , Q 53 , Q 54 , Q 55 and Q 56 , and Q in the formula (16) 61 and Q 62 Each independently represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms which may be substituted with at least one substituent selected from the group consisting of an alkyl group having 1 to 6 carbon atoms and a halogen atom, wherein Y in the formula (15) 1 and Y 2 Each independently represents an oxygen atom or a sulfur atom.

11. The electrophotographic apparatus according to claim 1, wherein the electron transport material comprises a compound represented by the following formula (E-1), a compound represented by the following formula (E-2), a compound represented by the following formula (E-3), a compound represented by the following formula (E-4), a compound represented by the following formula (E-5), a compound represented by the following formula (E-6), a compound represented by the following formula (E-7), or a compound represented by the following formula (E-8):

12. The electrophotographic apparatus according to claim 1, wherein the hole transport material comprises a compound represented by the following formula (20), a compound represented by the following formula (21), a compound represented by the following formula (22), a compound represented by the following formula (23), or a compound represented by the following formula (24): In the formula (20), R 11 , R 12 , R 13 and R 14 Each independently represents an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and a1, a2, a3 and a4 each independently represent an integer of 0 to 5. In the formula (21), R 21 , R 22 and R 23 Each independently represents an alkyl group having 1 to 6 carbon atoms, R 24 , R 25 and R 26 Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, b1, b2 and b3 each independently represent 0 or 1; in the formula (22), R 31 , R 32 and R 33 Each independently represents an alkyl group having 1 to 6 carbon atoms, R 34 represents an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, d1, d2 and d3 each independently represent an integer of 0 to 5; in the formula (23), R 41 , R 42 , R 43 , R 44 , R 45 and R 46 Each independently represents an alkyl group having 1 to 6 carbon atoms or a phenyl group, R 47 and R 48 Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group; e1, e2, e3, and e4 each independently represent an integer of 0 to 5; e5 and e6 each independently represent an integer of 0 to 4; and e7 and e8 each independently represent 0 or 1. In the formula (24), R 50 and R 51 each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group, and R 52 , R 53 , R 54 , R 55 , R 56 , R 57 and R 58 Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms, f1 and f2 each independently represent an integer of 0 to 2, and f3 and f4 each independently represent an integer of 0 to 5.

13. An electrophotographic apparatus according to claim 1, wherein the hole transport material comprises a compound represented by the following formula (H-1), a compound represented by the following formula (H-2), a compound represented by the following formula (H-3), a compound represented by the following formula (H-4), a compound represented by the following formula (H-5), a compound represented by the following formula (H-6), a compound represented by the following formula (H-7), a compound represented by the following formula (H-8), a compound represented by the following formula (H-9), a compound represented by the following formula (H-10), or a compound represented by the following formula (H-11):

14. The electrophotographic apparatus according to claim 1, wherein the charge generating material comprises oxytitanium phthalocyanine.

15. The electrophotographic apparatus according to claim 1, wherein the photosensitive layer contains a compound represented by the following formula (T-1) as an additive: 16 . The electrophotographic apparatus according to claim 1 , wherein a thickness of the photosensitive layer is 25 μm or more and 50 μm or less.

17. A process cartridge comprising: Electrophotographic photosensitive member; and a developing unit including a toner and configured to form a toner image on a surface of the electrophotographic photosensitive member with the toner, The process cartridge integrally supports the electrophotographic photosensitive member and the developing unit and is detachably mounted to a main body of the electrophotographic apparatus, wherein the electrophotographic photosensitive member comprises a single-layer type photosensitive layer comprising a charge generating material, a hole transporting material, an electron transporting material and a binder resin, wherein the photosensitive layer contains, as the binder resin, a polyarylate resin having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), wherein the toner is a toner comprising toner particles, wherein the toner particles each include a toner base particle and an external additive attached to the surface of the toner base particle, and wherein the external additive comprises at least aluminum oxide particles,

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