Electrophotographic device

Abstract

To provide an electrophotographic device that can prevent the occurrence of a pattern memory and allows stable image formation in a high temperature and high humidity environment.SOLUTION: An electrophotographic device has an electrophotographic photoreceptor, electrifying means, image exposure means, developing means having toner, transfer means, cleaning means, and transfer means. The electrophotographic photoreceptor has a single-layer photosensitive layer containing a binder resin, a charge generating material, a hole transport material, an electron transport material, and silicon atom-containing particles. The single-layer photosensitive layer is a surface layer of the electrophotographic photoreceptor. The charge generating material is metal-free phthalocyanine, or oxytitanium phthalocyanine. The silicon atom-containing particles are silica particles or silicone resin particles. The toner has toner particles containing a polyester resin having a polyethylene terephthalate segment.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to an electrophotographic apparatus.

Background Art

[0002] As the electrophotographic photoreceptor mounted on an electrophotographic apparatus, an organic electrophotographic photoreceptor in which a photosensitive layer (organic photosensitive layer) using an organic material as a photoconductive substance (charge generating substance or charge transporting substance) is provided on a support is widely used. As the photosensitive layer, a configuration containing a charge generating substance, a charge transporting substance, and a binder resin is known. For example, Patent Document 1 describes a technique for improving the electrical characteristics and wear resistance of a photoreceptor by using a specific polycarbonate resin. In recent years, in order to reduce the energy consumption of electrophotographic apparatuses, a technique for fixing toner at a low temperature has been proposed. Patent Document 2 describes a technique related to a toner having, as one of the resin components, a polyester obtained by reacting polyethylene terephthalate, an alcohol component, and a carboxylic acid component.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] As a result of investigations by the present inventors, it has been found that when the techniques disclosed in Patent Document 1 and Patent Document 2 are used simultaneously, there is room for improvement in pattern memory in a high-temperature and high-humidity environment. Pattern memory refers to a phenomenon in which an image pattern having a solid black band portion in the circumferential direction of the drum is repeatedly output for a part of the output image, and then when a full-tone halftone image without the solid black band portion is output, the portion that was the solid black band portion of the image pattern with the solid black band portion is output with a density difference in the full-tone halftone image. As a result of investigations by the present inventors, when an image is formed using an electrophotographic photoreceptor containing a metal-free phthalocyanine or oxytitanium phthalocyanine as a charge generating substance in a surface layer and a toner containing a polyester resin having a polyethylene terephthalate segment in a high temperature and high humidity environment, it has been found that a technical problem occurs in that pattern memory is likely to occur in the output image.

[0005] An object of the present disclosure is to provide an electrophotographic apparatus that suppresses the occurrence of pattern memory and enables stable image formation in a high temperature and high humidity environment.

Means for Solving the Problems

[0006] According to the present disclosure, there is provided an electrophotographic apparatus including: an electrophotographic photoreceptor; charging means for charging the surface of the electrophotographic photoreceptor; image exposure means for irradiating image exposure light onto the charged surface of the electrophotographic photoreceptor to form an electrostatic latent image on the surface of the electrophotographic photoreceptor; developing means having toner for developing the electrostatic latent image with the toner to form a toner image on the surface of the electrophotographic photoreceptor; transfer means for transferring the toner image from the surface of the electrophotographic photoreceptor to a transfer material; cleaning means for removing residual toner remaining on the surface of the electrophotographic photoreceptor after transferring the toner image from the surface of the electrophotographic photoreceptor to the transfer material, using a cleaning blade; and fixing means for fixing the toner image transferred to the transfer material to the transfer material. The electrophotographic photoreceptor has a single-layer photosensitive layer containing a binder resin, a charge generating substance, a hole transporting substance, an electron transporting substance, and silicon atom-containing particles. The single-layer photosensitive layer is the surface layer of the electrophotographic photoreceptor. The charge generating substance is metal-free phthalocyanine or oxytitanium phthalocyanine. The silicon atom-containing particles are silica particles or silicone resin particles. The toner has toner particles containing a polyester resin having a polyethylene terephthalate segment.

Effects of the Invention

[0007] According to the present disclosure, it is possible to provide an electrophotographic apparatus in which pattern memory is suppressed even under high temperature and high humidity conditions.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0009] Hereinafter, the present invention will be described in detail with reference to preferred embodiments. As a result of investigations by the present inventors, when an image is formed using, as a charge generating substance, an electrophotographic photoreceptor containing metal-free phthalocyanine or oxytitanium phthalocyanine in a surface layer and a toner containing a polyester resin having a polyethylene terephthalate segment, it has been clarified that a technical problem occurs in that pattern memory is likely to occur in the output image.

[0010] The present inventors presume the reasons for the occurrence of the technical problem in which pattern memory is likely to occur as follows. As a charge generating substance, an electrophotographic photoreceptor containing metal-free phthalocyanine or oxytitanium phthalocyanine in a surface layer may be affected by the amount of moisture (humidity) in the air in the use environment on the sensitivity of the electrophotographic photoreceptor. When the sensitivity of the electrophotographic photoreceptor changes depending on the amount of moisture on the surface of the electrophotographic photoreceptor, it leads to the occurrence of density differences in the halftone image. That is, it can be a cause of pattern memory occurrence. On the other hand, a toner containing a polyester resin having a polyethylene terephthalate segment tends to have a higher polarity compared to polyester resins generally used for toners, and thus is likely to have a higher affinity for water. Therefore, when the toner is present on the surface of the electrophotographic photoreceptor, the amount of moisture on the surface of the electrophotographic photoreceptor becomes higher than the amount of moisture in the air in the use environment. The influence becomes significant in a high temperature and high humidity environment. In a high-temperature and high-humidity environment, when forming an image using an electrophotographic photoreceptor containing a metal-free phthalocyanine or oxytitanium phthalocyanine as a charge-generating substance in the surface layer and a toner containing a polyester resin having a polyethylene terephthalate segment, since the amount of moisture present on the surface of the highly polar toner is large, the amount of moisture present on the surface of the electrophotographic photoreceptor in contact with the toner also increases. When outputting a solid black band image, since the amount of toner present on the surface of the electrophotographic photoreceptor increases, the influence of the increase in the amount of moisture on the surface of the electrophotographic photoreceptor also becomes large. The moisture on the surface of the electrophotographic photoreceptor affects the sensitivity of the charge-generating substance, resulting in a difference in sensitivity between the solid black band portion and the solid white band portion. When an image is output with the sensitivity difference remaining, a density difference occurs between the solid black band portion and the solid white band portion, and this density difference is considered to appear on the image as a pattern memory.

[0011] As a result of the study by the present inventors, it has been found that an electrophotographic apparatus with suppressed pattern memory can be obtained by incorporating silica particles or silicone resin particles as silicon atom-containing particles in the surface layer of the electrophotographic photoreceptor.

[0012] Regarding the reason why the electrophotographic apparatus of the present disclosure is excellent in the pattern memory suppression effect, the present inventors speculate as follows. The surface layer of the electrophotographic photoreceptor of the present disclosure has a binder resin, a hole transport substance, an electron transport substance, silicon atom-containing particles, and a charge-generating substance. In the surface layer of the electrophotographic photoreceptor, in particular, it is speculated that the silicon atom-containing particles intervening between the surface of the electrophotographic photoreceptor and the charge-generating substance present in the surface layer suppress the influence of moisture from the surface of the electrophotographic photoreceptor on the charge-generating substance. It is speculated that when the influence of surface moisture on the charge-generating substance from the surface of the electrophotographic photoreceptor becomes small, the sensitivity change due to the influence of moisture becomes small, and the pattern memory is suppressed.

[0013] <Electrophotographic photoreceptor> The electrophotographic photoreceptor of the electrophotographic apparatus of the present disclosure has a single-layer photosensitive layer containing a binder resin, a charge generating substance, a hole transporting substance, an electron transporting substance, and silicon atom-containing particles, and the single-layer photosensitive layer constitutes the surface layer of the electrophotographic photoreceptor. Further, the electrophotographic photoreceptor of the electrophotographic apparatus of the present disclosure is characterized by having a surface layer containing a metal-free phthalocyanine or oxytitanium phthalocyanine as a charge generating substance, and silica particles or silicone resin particles as silicon atom-containing particles.

[0014] In addition to the surface layer, the electrophotographic photoreceptor of the present disclosure may have a support, a conductive layer, and an undercoat layer described later. As a method for manufacturing the electrophotographic photoreceptor of the present disclosure, a method of preparing coating liquids for each layer described later, sequentially coating desired layers, and drying them can be mentioned. At this time, examples of the coating method of the coating liquid include dip coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, ring coating, and the like. Among these, dip coating is preferable from the viewpoints of efficiency and productivity. Hereinafter, each layer will be described.

[0015] <Support> The electrophotographic photoreceptor of the present disclosure preferably has a support. The support of the electrophotographic photoreceptor is preferably a conductive one (conductive support). Examples of the shape of the support include a cylindrical shape, a belt shape, and a sheet shape. Among these, a cylindrical support is preferable. Further, an electrochemical treatment such as anodic oxidation, a blasting treatment, a cutting treatment, or the like may be performed on the surface of the support. Examples of the material of the support include metals, resins, and glasses. Examples of the metal include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. Among these, an aluminum support using aluminum is preferable. Further, it is preferable to impart conductivity to resins and glasses by treatments such as mixing or coating a conductive material.

[0016] <Conductive layer> A conductive layer may be provided on the support. By providing the conductive layer, scratches and unevenness on the surface of the support can be concealed, and light reflection on the support surface can be controlled. The conductive layer preferably contains conductive particles and a resin. Examples of the material of the conductive particles include metal oxides, metals, carbon black, etc. Examples of the metal oxides include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, strontium titanate, magnesium oxide, antimony oxide, bismuth oxide, etc. Examples of the metals include aluminum, nickel, iron, chromium, copper, zinc, silver, etc. Among these, it is preferable to use metal oxide particles as the conductive particles, and particularly, it is more preferable to use titanium oxide particles, tin oxide particles, and zinc oxide particles. When using metal oxide particles as the conductive particles, the surface of the metal oxide particles may be treated with a silane coupling agent or the like, or the metal oxide particles may be doped with elements such as phosphorus and aluminum or their oxides. Further, the conductive particles may have a laminated structure having core material particles and a coating layer covering the particles. Examples of the core material particles include titanium oxide particles, barium sulfate particles, zinc oxide particles, etc. Examples of the coating layer include metal oxide particles such as tin oxide. When using metal oxide particles as the conductive particles, the volume average particle diameter thereof is preferably 1 nm or more and 500 nm or less, and more preferably 3 nm or more and 400 nm or less.

[0017] Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, alkyd resin, etc. Further, the conductive layer may further contain silicone oil, resin particles, a concealer, etc. Examples of the concealer include titanium oxide. The conductive layer can be formed by preparing a coating liquid for the conductive layer containing each of the above materials and a solvent, forming this coating film on a support, and drying it. Examples of the solvent used in the coating liquid for the conductive layer include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, aromatic hydrocarbon solvents, and the like. Examples of the dispersion method for dispersing conductive particles in the coating liquid for the conductive layer include methods using a paint shaker, a sand mill, a ball mill, and a liquid collision type high-speed disperser. The average film thickness of the conductive layer is preferably 1 μm or more and 50 μm or less, and particularly preferably 3 μm or more and 40 μm or less.

[0018] <Undercoat layer> In the present disclosure, an undercoat layer may be provided on the support or the conductive layer. By providing the undercoat layer, the interlayer adhesion function can be enhanced, and a charge injection blocking function can be imparted. The undercoat layer preferably contains a resin. Further, the undercoat layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinyl phenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, polyamide resin, polyamic acid resin, polyimide resin, polyamideimide resin, cellulose resin, and the like. Examples of the polymerizable functional group of the monomer having a polymerizable functional group include isocyanate group, blocked isocyanate group, methylol group, alkylated methylol group, epoxy group, metal alkoxide group, hydroxy group, amino group, carboxy group, thiol group, carboxylic anhydride group, carbon-carbon double bond group, and the like.

[0019] Further, the undercoat layer may further contain an electron transport material, metal oxide particles, metal particles, a conductive polymer, etc. for the purpose of enhancing the electrical properties. Among these, it is preferable to use an electron transport material and metal oxide particles. Examples of the electron transporting material include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, aryl halide compounds, silole compounds, boron-containing compounds, etc. As the electron transporting material, an electron transporting material having a polymerizable functional group may be used and copolymerized with the monomer having the above-mentioned polymerizable functional group to form an undercoat layer as a cured film. Examples of the metal oxide particles include particles such as indium tin oxide, tin oxide, indium oxide, titanium oxide, strontium titanate, zinc oxide, and aluminum oxide. Silicon dioxide particles can also be used. Examples of the metal particles include particles such as gold, silver, and aluminum.

[0020] The metal oxide particles contained in the undercoat layer may be surface-treated using a surface treatment agent such as a silane coupling agent before use. As a method for surface-treating the metal oxide particles, a general method is used. For example, a dry method or a wet method can be mentioned. In the dry method, while stirring the metal oxide particles in a mixer capable of high-speed stirring such as a Henschel mixer, an alcohol aqueous solution, an organic solvent solution, or an aqueous solution containing a surface treatment agent is added, and after uniformly dispersing, drying is performed. In the wet method, the metal oxide particles and the surface treatment agent are stirred in a solvent or dispersed using a sand mill or the like with glass beads or the like, and after dispersion, the solvent is removed by filtration or distillation under reduced pressure. After removing the solvent, it is preferably baked at 100°C or higher.

[0021] The undercoat layer may further contain an additive, and for example, known materials such as metal particles such as aluminum particles, conductive particles such as carbon black, charge transporting materials, metal chelate compounds, and organometallic compounds can be contained. The undercoat layer can be formed by preparing a coating solution for the undercoat layer containing each of the above materials and a solvent, forming this coating film on a support or a conductive layer, and drying and / or curing it. Examples of the solvent used in the coating solution for the undercoat layer include organic solvents such as alcohol, sulfoxide, ketone, ether, ester, aliphatic halogenated hydrocarbon, and aromatic compounds. In the present disclosure, it is preferable to use alcohol-based and ketone-based solvents. Examples of the dispersion method for preparing the coating solution for the undercoat layer include methods using a homogenizer, an ultrasonic disperser, a ball mill, a sand mill, a roll mill, a vibration mill, an attritor, and a liquid collision type high-speed disperser. The average film thickness of the undercoat layer is preferably 0.1 μm or more and 50 μm or less, more preferably 0.2 μm or more and 40 μm or less, and particularly preferably 0.3 μm or more and 30 μm or less.

[0022] <Surface layer> The surface layer of the electrophotographic photoreceptor of the present invention is a photosensitive layer containing a binder resin, a charge generating substance, a hole transporting substance, an electron transporting substance, and silicon atom-containing particles. The charge generating substance contained in the surface layer is metal-free phthalocyanine and oxytitanium phthalocyanine. The metal-free phthalocyanine can be represented by the following formula (G-1). The oxytitanium phthalocyanine can be represented by the following formula (G-2).

Chemical formula

[0023] The silicon atom-containing particles contained in the surface layer are silica particles and silicone resin particles. Examples of commercially available silica particles that can be used in the present disclosure include, for example, silica particles manufactured by Nippon Aerosil Co., Ltd.: AEROSIL RX200, AEROSIL RX300, AEROSIL RY200, AEROSIL R974, AEROSIL NAX50, and the like. Examples of commercially available silicone resin particles that can be used in the present disclosure include, for example, silicone resin particles manufactured by Shin-Etsu Chemical Co., Ltd.: X-52-854, X-52-1621, KMP-590, and silicone resin particles manufactured by Nikko Rika Co., Ltd.: MSP-N050, MSP-N080, and the like.

[0024] From the viewpoint of achieving both pattern memory suppression and repeated potential fluctuation suppression, it is preferable that the content of silicon atom-containing particles in the surface layer is 0.1% by mass or more and 10.0% by mass or less with respect to the total mass of the surface layer. If the content is less than 0.1% by mass, pattern memory may deteriorate. If the content is more than 10.0% by mass, repeated potential fluctuations may deteriorate. From the viewpoint of achieving both pattern memory suppression and repeated potential fluctuation suppression, it is preferable that the content of silicon atom-containing particles in the surface layer is 10% by mass or more and 1400% by mass or less with respect to the content of charge generation substances in the surface layer. If the content is less than 10% by mass, pattern memory may deteriorate. If the content is more than 1400% by mass, repeated potential fluctuations may deteriorate.

[0025] The number average primary particle diameter of the silicon atom-containing particles contained in the surface layer is determined from the cross section of the surface layer. Specifically, 50 silicon atom-containing particles in the cross section of the surface layer are observed and an image is acquired. Elliptical fitting is performed on the image to obtain the longest diameter. The average of the 10 largest longest diameters obtained is defined as the number average primary particle diameter of the silicon atom-containing particles. From the perspective of achieving both pattern memory suppression and repeated potential fluctuation suppression, it is preferable that the number average primary particle diameter of the silicon atom-containing particles contained in the surface layer is 10 nm or more and 2000 nm or less. If the number average primary particle diameter is less than 10 nm, pattern memory may deteriorate. If the number average primary particle diameter is greater than 2000 nm, repeated potential fluctuation may deteriorate.

[0026] Examples of the binder resin include polycarbonate resin, polyarylate resin, acrylic resin, polystyrene resin, etc. Among these, thermoplastic resins are preferable, and particularly, polycarbonate resin and polyarylate resin are preferable.

[0027] Examples of the hole transport material include oxadiazole derivatives such as 2,5-bis(p-diethylaminophenyl)-1,3,4-oxadiazole; pyrazoline derivatives such as 1,3,5-triphenyl-pyrazoline, 1-[pyridyl-(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminostyryl)pyrazoline; aromatic tertiary amino compounds such as triphenylamine, N,N′-bis(3,4-dimethylphenyl)biphenyl-4-amine, tri(p-methylphenyl)aminyl-4-amine, dibenzylaniline; aromatic tertiary diamino compounds such as N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzidine, 1,2,4-triazine derivatives such as 3-(4′-dimethylaminophenyl)-5,6-di-(4′-methoxyphenyl)-1,2,4-triazine; hydrazone derivatives such as 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone; quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline; benzofuran derivatives such as 6-hydroxy-2,3-di(p-methoxyphenyl)benzofuran; α-stilbene derivatives such as p-(2,2-diphenylvinyl)-N,N-diphenylaniline; enamine derivatives; carbazole derivatives such as N-ethylcarbazole; poly-N-vinylcarbazole and its derivatives, etc.; polymers having a group composed of the above-mentioned compounds in the main chain or side chain; and the like. These hole transport materials may be used alone or in combination of two or more.

[0028] Examples of the electron transport material include quinone compounds, diimide compounds, hydrazone compounds, malononitrile-based compounds, thiopyran-based compounds, trinitrothioxanthone-based compounds, 3,4,5,7-tetranitro-9-fluorenone-based compounds, dinitroanthracene-based compounds, dinitroacridine-based compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroacridine, succinic anhydride, maleic anhydride, or dibromo maleic anhydride. Examples of the quinone-based compounds include diphenoquinone-based compounds, azoquinone-based compounds, anthraquinone-based compounds, naphthoquinone-based compounds, nitroanthraquinone-based compounds, or dinitroanthraquinone-based compounds. These electron transport materials may be used alone or in combination of two or more.

[0029] Further, the surface layer may contain additives such as an antioxidant, an ultraviolet absorber, a plasticizer, a leveling agent, a lubricity-imparting agent, and a wear resistance improver. Specifically, examples include hindered phenol compounds, hindered amine compounds, biphenyl derivatives, terphenyl compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, and silicone oils.

[0030] The average film thickness of the surface layer is preferably 5 μm or more and 50 μm or less, more preferably 8 μm or more and 40 μm or less, and particularly preferably 10 μm or more and 35 μm or less.

[0031] The surface layer can be formed by preparing a coating liquid for the surface layer containing each of the above materials and a solvent, forming this coating film, and drying it. Examples of the solvent used in the coating liquid for the surface layer include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0032] <Toner and Developer> The toner used in the electrophotographic apparatus of the present disclosure is a toner having toner particles containing a polyester resin having polyethylene terephthalate segments. Hereinafter, the toner according to the present disclosure will be described.

[0033] <Polyester resin having polyethylene terephthalate segments> As components constituting the polyester resin having polyethylene terephthalate, polyethylene terephthalate segments, dihydric or higher alcohol monomer components, acid monomer components such as dihydric or higher carboxylic acids, dihydric or higher carboxylic anhydrides, and dihydric or higher carboxylic acid esters, etc. can be mentioned.

[0034] <Polyethylene terephthalate segments> The polyethylene terephthalate segments of the present disclosure have a structure in which the structural unit of polyethylene terephthalate (C 10 H8O4) is repeated. The polyethylene terephthalate segments of the present disclosure can use those produced according to a conventional method by a condensation reaction or transesterification reaction of ethylene glycol and terephthalic acid, dimethyl terephthalate, etc., or recovered polyethylene terephthalate resin can also be used. Polyethylene terephthalate resin is used in various products such as containers and films, and it is preferable to recover and reuse it from the viewpoint of environmental protection. The recovered polyethylene terephthalate resin does not contain impurities that affect toner characteristics and reactions in the manufacturing process, and its type is not limited as long as it has an appropriate purity.

[0035] <Dihydric or higher alcohol monomer components> Examples of the alcohol monomer component with a valency of 2 or more include alkylene oxide adducts of bisphenol A such as polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene(3.3)-2,2-bis(4-hydroxyphenyl)propane, polyoxyethylene(2.0)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene(2.0)-polyoxyethylene(2.0)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene(6)-2,2-bis(4-hydroxyphenyl)propane, ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, neopentyl glycol, polyethylene glycol, polypropylene glycol, and the like.

[0036] <Acid monomer component> On the other hand, examples of the acid monomer component such as dicarboxylic acids with a valency of 2 or more, dicarboxylic acid anhydrides with a valency of 2 or more, and dicarboxylic acid esters with a valency of 2 or more include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid or their anhydrides; alkyldicarboxylic acids such as oxalic acid, malonic acid, succinic acid, adipic acid, maleic acid, fumaric acid, citraconic acid, and itaconic acid or their anhydrides.

[0037] <Method for producing a polyester resin having a polyethylene terephthalate segment> The polyester resin having a polyethylene terephthalate segment of the present disclosure can be produced according to a conventional polyester synthesis method. For example, a desired polyester resin can be obtained by subjecting a carboxylic acid monomer and an alcohol monomer to an esterification reaction or a transesterification reaction, and then performing a polycondensation reaction according to a conventional method under reduced pressure or by introducing nitrogen gas. Furthermore, it is more preferable because the use of a toner as shown below can improve low-temperature fixability and scratch resistance. In the present disclosure, a toner having toner particles containing a binder resin, wherein the binder resin contains an amorphous resin A and a crystalline polyester C, The amorphous resin A is the polyester resin, and as a structure forming a polyester skeleton, (i) the polyethylene terephthalate segment, and (ii) at least one structure selected from the group consisting of units represented by the following formulas (1) to (4), and has

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0038] Hereinafter, the reasons for improving the low-temperature fixability and scratch resistance will be explained. As a result of the study by the present inventors, it has been found that in a toner having the following characteristics, good low-temperature fixability is exhibited while improving the scratch resistance. (i) It can flexibly deform the three-dimensional structure in the direction in which an external force is applied. (ii) When the external force is removed, it can return to the original three-dimensional structure. Such a toner can be achieved by having the above-described configuration.

[0039] The amorphous resin A has at least one structure selected from the group consisting of the units represented by formulas (1) to (4), and the SP value of the amorphous resin A and the crystalline polyester C is controlled, so that it has an affinity for the crystalline polyester C. Therefore, in the fixed image, the amorphous resin A is affected by the crystalline polyester C and becomes flexible. And this structure can flexibly deform the three-dimensional structure in the direction of the external force received without breaking the molecular chain in order to disperse the given external force. Further, since the amorphous resin A contains polyethylene terephthalate segments, it has a repeating structure of a condensate of terephthalic acid and ethylene glycol in the polyester backbone. The structure derived from ethylene glycol in the polyethylene terephthalate segment has ester groups at a very close molecular distance for two carbon atoms because both ends of ethylene glycol are ester-reacted. Therefore, the amorphous resin A has ester groups localized in the resin. Also, the phosphorus compound in which three non-bonding electron pairs in the outermost shell have reacted has a bonding point at a very close molecular distance. Therefore, the amorphous resin A can interact with the localized ester groups in the amorphous resin A around the phosphorus element of the phosphorus compound to form a three-dimensional crosslinked structure. By having this structure, when the given external force is removed, it can return from the deformed state to the original three-dimensional structure. As described above, it is considered that by adopting the configuration of the present disclosure, excellent low-temperature fixability and scratch resistance can be obtained.

[0040] The amorphous resin A of the present disclosure has at least one structure selected from the group consisting of units represented by formulas (1) to (4) as a structure forming a polyester backbone. The structure of the long-chain hydrocarbon group such as an alkyl group or an alkenyl group contained in the units represented by formulas (1) to (4) is a relatively low-polarity structure compared to the structure derived from ethylene glycol of the polyethylene terephthalate segment described above. Therefore, the structure of the long-chain hydrocarbon group such as an alkyl group or an alkenyl group contained in the units represented by formulas (1) to (4) becomes flexible by increasing the affinity with the crystalline polyester C. And this structure can flexibly deform the three-dimensional structure in the direction in which the external force is received without breaking the molecular chain in order to disperse the given external force. As a result, excellent scratch resistance can be obtained by realizing an improvement in elastic deformation. Also, the SP A (cal / cm 3 ) 0.5 of the amorphous resin A and the SP C (cal / cm 3 ) 0.5 of the crystalline polyester C satisfy the above formula (C). When SP A -SP C satisfies the above formula (C), the amorphous resin A and the crystalline polyester C are likely to be compatible, so the crystalline polyester C can act on the structure having a long-chain hydrocarbon group such as an alkyl group or an alkenyl group of the amorphous resin A smoothly. Therefore, this structure becomes flexible by increasing the affinity with the crystalline polyester C. And the structure can flexibly deform the three-dimensional structure in the direction in which the external force is received without breaking the molecular chain in order to disperse the given external force. As a result, excellent scratch resistance can be obtained by realizing an improvement in elastic deformation characteristics.

[0041] Furthermore, the toner of the present disclosure contains a phosphorus element derived from a phosphorus compound, and W P(ppm) satisfies the above formula (D). When the phosphorus element content in the toner satisfies the above formula (D), it indicates that there is a sufficient amount of phosphorus element that interacts with the localized ester groups in the amorphous resin A around the phosphorus element to form a three-dimensional cross-linked structure. That is, it is the minimum amount of phosphorus element that can flexibly change the three-dimensional structure in the direction of the external force received without breaking the molecular chain to disperse the given external force, and the maximum amount of phosphorus element that can ensure a certain plastic deformation to guarantee low-temperature fixability.

[0042] <Amorphous resin A> The amorphous resin A is a polyester resin and has the following (i) and (ii) as the structures forming the polyester backbone.

[0043] (i) Polyethylene terephthalate segment (ii) At least one structure selected from the group consisting of the units represented by formulas (1) to (4) The polyethylene terephthalate segment used in the amorphous resin A is obtained by polycondensing ethylene glycol and terephthalic acid.

[0044] And the synthesis of the polyester resin can be carried out in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and further, if necessary, in the presence of an esterification co-catalyst, a polymerization inhibitor, etc., preferably at a temperature of 180 °C or higher and 250 °C or lower.

[0045] Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropoxide bistriethanolamineate. Among these, tin compounds such as tin(II) 2-ethylhexanoate are preferred. The amount of the esterification catalyst used is preferably 0.01 part by mass or more, more preferably 0.1 part by mass or more, and preferably 1.5 parts by mass or less, more preferably 1.0 part by mass or less, based on 100 parts by mass of the raw material monomers (alcohol component, carboxylic acid component, and PET). Examples of the esterification cocatalyst include gallic acid. The amount of the esterification cocatalyst used is preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, and preferably 0.5 part by mass or less, more preferably 0.1 part by mass or less, based on 100 parts by mass of the raw material monomers. Examples of the polymerization inhibitor include tert-butylcatechol. The amount of the polymerization inhibitor used is preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, and preferably 0.5 part by mass or less, more preferably 0.1 part by mass or less, based on 100 parts by mass of the raw material monomers.

[0046] In the synthesis of the polyester resin, polyethylene terephthalate may be present from the start of the polycondensation reaction or added to the reaction system during the polycondensation reaction. In order for the polyethylene terephthalate segment to be incorporated into the main skeleton of the polyester in a somewhat blocky form, the addition time of polyethylene terephthalate is preferably at a stage where the reaction rate of the alcohol component and the carboxylic acid component is 10% or less, more preferably 5% or less. Here, the reaction rate refers to the value of (mol of generated reaction water amount) / (mol of theoretical generated water amount)×100.

[0047] In addition, the polyethylene terephthalate segment contained in the amorphous resin A can use used polyethylene terephthalate (so-called recycled PET). Recycling polyethylene terephthalate is preferable from the environmental viewpoint.

[0048] Used PET is collected, and the collected PET is washed, sorted so that other materials and garbage are not mixed, and after removing labels, etc., it is crushed into flakes or the like. The crushed material can be used as it is, or the crushed material can be kneaded and coarsely crushed and used. When chemical substances adsorbed on the surface of the PET bottle cannot be sufficiently removed by normal washing, alkali washing may be carried out. When a part of the crushed material is hydrolyzed by alkali washing, in order to restore the decreased degree of polymerization, it is preferable to melt the washed crushed material and subject the pelletized material to solid-phase polymerization. The solid-phase polymerization step can be carried out by continuously solid-phase polymerizing the washed flakes or the flakes melted and extruded into pellets in an inert gas such as nitrogen gas or rare gas at 180 to 245 ° C, preferably 200 to 240 ° C. Further, the washed crushed material may be decomposed into monomer units by depolymerization and then resynthesized and used. Further, the recycled PET is not limited to the above-mentioned used PET, and fiber scraps or pellets of off-spec PET discharged from the factory may be used.

[0049] In addition, in order to incorporate at least one unit selected from the group consisting of the units represented by formulas (1) to (4) into the amorphous resin A, the following monomers can be used. 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, hexadecanedioic acid, octadecanedioic acid, dodecenyl succinic acid, n-octyl succinic acid, isododecenyl succinic acid, dodecyl succinic acid, isooctenyl succinic acid, hexadecyl succinic acid, etc. can be mentioned.

[0050] Among the units represented by formulas (1) to (4), the units represented by formulas (1) and (2) are preferable. The fact that an alkyl group or alkenyl group having 6 to 16 carbon atoms branches from the main chain of the polyester skeleton increases the affinity with the release agent and further increases the dispersibility of the release agent.

[0051] In addition to the above-described structures and monomers, as components for obtaining the amorphous resin A, other polyhydric alcohols (alcohols having two or more hydroxyl groups), polyvalent carboxylic acids (carboxylic acids having two or more carboxyl groups), their acid anhydrides or their lower alkyl esters may be used.

[0052] As the polyhydric alcohol monomers, the following polyhydric alcohol monomers can be used. As the dihydric alcohol components, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, and bisphenol represented by the formula (I) and its derivatives;

Chemical formula

Chemical formula

[0053] As the alcohol components having three or more hydroxyl groups, for example, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene can be mentioned. Among these, preferably, glycerol, trimethylolpropane, and pentaerythritol are used.

[0054] These divalent alcohols and polyhydric alcohols of three or more valences can be used alone or in combination of two or more.

[0055] Examples of the divalent carboxylic acid component include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, azelaic acid, malonic acid, anhydrides of these acids, and lower alkyl esters of these acids. Among these, maleic acid, fumaric acid, and terephthalic acid are preferably used.

[0056] Examples of the polyhydric carboxylic acid of three or more valences, its acid anhydride, or its lower alkyl ester include 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra(methylenecarboxyl)methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, Empol trimer acid, acid anhydrides of these acids, or lower alkyl esters of these acids. Among these, in particular, 1,2,4-benzenetricarboxylic acid, that is, trimellitic acid or its derivative, is inexpensive and easy to control the reaction, so it is preferably used. These divalent carboxylic acids and polyhydric carboxylic acids of three or more valences can be used alone or in combination of two or more.

[0057] The method for producing the amorphous resin A is not particularly limited, and known methods can be used. For example, the aforementioned alcohol monomer and carboxylic acid monomer are charged simultaneously, and polymerized through an esterification reaction or transesterification reaction, and a condensation reaction to produce a polyester resin. Also, the polymerization temperature is not particularly limited, but a range of 180°C or higher and 290°C or lower is preferable. When polymerizing the polyester unit, for example, polymerization catalysts such as titanium-based catalysts, tin-based catalysts, zinc acetate, antimony trioxide, and germanium dioxide can be used. In particular, the amorphous resin A is more preferably a polyester resin polymerized using a tin-based catalyst.

[0058] The amorphous resin A may be a polyester resin having a vinyl resin portion. As a method for obtaining a polyester resin to which a vinyl resin is bonded, a method using a monomer component capable of reacting with both the vinyl resin and the polyester unit is preferable. As such a monomer, a monomer having an unsaturated double bond and a carboxy group or a hydroxy group is preferable. For example, unsaturated dicarboxylic acids such as phthalic acid, maleic acid, citraconic acid, and itaconic acid or their anhydrides, and acrylic acid or methacrylic acid esters can be mentioned.

[0059] Also, from the viewpoint of low-temperature fixing properties and the like, it is preferable that the peak molecular weight of the amorphous resin A is 3500 or more and 20000 or less. The glass transition temperature is preferably 40°C to 70°C.

[0060] In addition to the amorphous resin A, various resins conventionally known as binder resins can be used in combination as the amorphous resin. Examples of such resins include phenolic resins, natural resin-modified phenolic resins, natural resin-modified maleic resins, acrylic resins, methacrylic resins, polyvinyl acetate resins, silicone resins, polyester resins, polyurethanes, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resins, coumarone indene resins, petroleum resins, and the like.

[0061] <Crystalline polyester C> As monomers used for the polyester unit of the crystalline polyester C used in the toner of the present disclosure, a polyhydric alcohol (a dihydric or trihydric or higher alcohol), a polyvalent carboxylic acid (a dihydric or trihydric or higher carboxylic acid), its acid anhydride or its lower alkyl ester are used.

[0062] As the polyhydric alcohol monomer used for the polyester unit of the crystalline polyester C, the following polyhydric alcohol monomers can be used.

[0063] The polyhydric alcohol monomer is not particularly limited, but is preferably a chain (more preferably a straight-chain) aliphatic diol. For example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-butanediol, 1,4-butadiene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, nonamethylene glycol, decamethylene glycol, neopentyl glycol can be mentioned. Among these, in particular, straight-chain aliphatic α,ω-dials such as ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol are preferably exemplified.

[0064] In the present disclosure, polyhydric alcohol monomers other than the above polyhydric alcohol can also be used. Examples of the dihydric alcohol monomers among the polyhydric alcohol monomers include aromatic alcohols such as polyoxyethylenated bisphenol A and polyoxypropylenated bisphenol A; and 1,4-cyclohexanedimethanol. Examples of the polyhydric alcohol monomers having three or more hydroxyl groups among the polyhydric alcohol monomers include aromatic alcohols such as 1,3,5-trihydroxymethylbenzene; and aliphatic alcohols such as pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin element, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, and trimethylolpropane.

[0065] As the polycarboxylic acid monomer used for the polyester unit of the crystalline polyester C, the following polycarboxylic acid monomers can be used.

[0066] The polycarboxylic acid monomer is not particularly limited, but is preferably a chain (more preferably a linear) aliphatic dicarboxylic acid. Specific examples include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, glutaconic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, and itaconic acid, and also include acid anhydrides thereof or those obtained by hydrolyzing lower alkyl esters.

[0067] In the present disclosure, polycarboxylic acids other than the above polycarboxylic acid monomers can also be used. Among other polycarboxylic acid monomers, examples of the divalent carboxylic acid include aromatic carboxylic acids such as isophthalic acid and terephthalic acid; aliphatic carboxylic acids such as n-dodecyl succinic acid and n-dodecenyl succinic acid; and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid, and acid anhydrides or lower alkyl esters thereof are also included. Among other carboxylic acid monomers, examples of the polycarboxylic acid having three or more valences include aromatic carboxylic acids such as 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and pyromellitic acid, and aliphatic carboxylic acids such as 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, and 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, and derivatives such as acid anhydrides or lower alkyl esters thereof are also included.

[0068] Further, the crystalline polyester C is preferably a modified crystalline polyester having a structure in which the hydroxy group at the main chain terminal is end-capped with an aliphatic monocarboxylic acid having 16 to 31 carbon atoms, or a modified crystalline polyester having a structure in which the carboxy group at the main chain terminal is end-capped with an aliphatic monoalcohol having 15 to 30 carbon atoms.

[0069] Examples of the aliphatic monocarboxylic acid monomer having 16 to 31 carbon atoms include palmitic acid (hexadecanoic acid), margaric acid (heptadecanoic acid), stearic acid (octadecanoic acid), nonadecylic acid, arachidic acid (icosanoic acid), heneicosanoic acid, docosanoic acid, tetracosanoic acid, hexacosanoic acid, octacosanoic acid, and triacontanoic acid.

[0070] Examples of aliphatic monoalcohols having 15 to 30 carbon atoms include cetyl alcohol, palmityl alcohol (hexadecanol), margaryl alcohol (heptadecanol), stearyl alcohol (octadecanol), nonadecanol, arachidyl alcohol (icosanol), heneicosanol, behenyl alcohol, lignoceryl alcohol, ceril alcohol, 1-heptacosanol, montanyl alcohol, 1-nonacosanol, and myristyl alcohol.

[0071] Crystalline polyester C can be produced according to a conventional polyester synthesis method. For example, after subjecting the above-described carboxylic acid monomer and alcohol monomer to an esterification reaction or a transesterification reaction, a crystalline polyester can be obtained by performing a polycondensation reaction under reduced pressure or while introducing nitrogen gas according to a conventional method. Thereafter, by further adding the above aliphatic compound and performing an esterification reaction, a desired crystalline polyester can be obtained.

[0072] The above esterification or transesterification reaction can be carried out using a conventional esterification catalyst or transesterification catalyst such as sulfuric acid, titanium butoxide, dibutyltin oxide, manganese acetate, magnesium acetate, etc., as necessary.

[0073] The above polycondensation reaction can be carried out using a known catalyst such as a conventional polymerization catalyst, for example, titanium butoxide, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, germanium dioxide, etc. The polymerization temperature and the amount of catalyst are not particularly limited and may be determined as appropriate.

[0074] In the esterification or transesterification reaction or the polycondensation reaction, a method of charging all monomers at once may be used to increase the strength of the resulting crystalline polyester. Also, a method such as reacting a divalent monomer first and then adding and reacting a trivalent or higher monomer to reduce low molecular weight components may be used.

[0075] The melting point of the crystalline polyester C is preferably 70°C to 110°C, more preferably 80°C to 100°C, from the viewpoint of low-temperature fixability. In the toner of the present disclosure, the crystalline polyester C is preferably used in an amount of 3 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the amorphous resin, from the viewpoints of low-temperature fixability, rub resistance, and charge retention property in a high-temperature and high-humidity environment.

[0076] <Phosphorus compound> Examples of the phosphorus compound used in the toner of the present disclosure include trisodium phosphate, trimethyl phosphate, triethyl phosphate, tri-2-ethylhexyl phosphate, tris(isopropylphenyl) phosphate, triphenyl phosphate, tributyl phosphate, trimethyl phosphite, tributyl phosphite, triphenyl phosphite, and the like. Among them, trivalent phosphorus compounds that easily form three-dimensional crosslinks are preferred.

[0077] The content W of phosphorus element p is as described above. Further, in order to form a three-dimensional crosslinked structure, it is preferable that the used polyethylene terephthalate (so-called recycled PET) is used because the blocks of polyethylene terephthalate are easily formed, so that ester groups with close molecular distances are more aggregated and a strong three-dimensional crosslinked structure can be formed. This structure can return to its original three-dimensional structure when the applied external force is removed.

[0078] <Release agent> The toner particles may contain wax as a release agent. Examples of the wax include polyethylene wax, polypropylene wax, polypropylene copolymer wax, microcrystalline wax, paraffin wax, Fischer-Tropsch wax, carnauba wax, rice wax, candelilla wax, montan wax, and the like.

[0079] <Colorant> The toner may contain a colorant. Examples of the colorant include known organic pigments, oil dyes, magnetic materials, etc. Examples of the colorant include carbon black, phthalocyanine blue, permanent brown FG, brilliant fast scarlet, pigment red 122, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, isoindoline, disazo yellow, benzidine yellow, monoazo dyes, disazo dyes, etc.

[0080] <Charge control agent> The toner particles may contain a charge control agent as needed. Known charge control agents can be used, but particularly when combined with the photoreceptor used in the present disclosure, it is preferable to use a positive charge control agent. Examples of the positive charge control agent include quaternary ammonium salt compounds, triphenylmethane compounds, imidazole compounds, nigrosine dyes, etc. Examples of the negative charge control agent include metal salicylate compounds, metal naphthenate compounds, dicarboxylic acid metal compounds, polymer-type compounds having sulfonic acid or carboxylic acid in the side chain, polymer-type compounds having sulfonate or sulfonic acid esterified products in the side chain, polymer-type compounds having carboxylate or carboxylic acid esterified products in the side chain, boron compounds, urea compounds, silicon compounds, calixarenes.

[0081] <Inorganic fine particles> The toner may contain inorganic fine particles as needed. The inorganic fine particles may be incorporated into the toner particles or mixed with the toner particles as an external additive. Examples of the inorganic fine particles include fine particles such as silica fine particles, titanium oxide fine particles, alumina fine particles, or their complex oxide fine particles. Among the inorganic fine particles, silica fine particles and titanium oxide fine particles are preferable for improving fluidity and charge uniformity. The inorganic fine particles are preferably hydrophobized with a hydrophobizing agent such as a silane compound, silicone oil, or a mixture thereof.

[0082] <External additive> As the external additive, in addition to the above inorganic fine particles, organic fine particles such as melamine resin fine particles and polytetrafluoroethylene resin fine particles may be used.

[0083] From the viewpoint of improving fluidity, the median diameter (D50) in terms of the number standard of the external additive is preferably 10 nm or more, and preferably 250 nm or less, more preferably 200 nm or less, and still more preferably 90 nm or less.

[0084] The content of the external additive is preferably 0.1 part by mass to 10.0 parts by mass with respect to 100 parts by mass of the toner particles. Mixing of the toner particles and the external additive can be carried out using a known mixer such as a Henschel mixer.

[0085] <Developer> The toner can be used as a one-component developer, but in order to further improve dot reproducibility and supply a stable image over a long period of time, it is preferably mixed with a magnetic carrier and used as a two-component developer. As the magnetic carrier, for example, generally known ones such as metal particles such as iron, cobalt, and nickel, and magnetic materials such as ferrite can be used.

[0086] <Method for manufacturing toner particles> The method for manufacturing toner particles is not particularly limited, and known methods such as a pulverization method, a suspension polymerization method, a dissolution suspension method, an emulsion aggregation method, and a dispersion polymerization method can be used. Among them, from the viewpoint of controlling the wax on the surface of the toner particles, the pulverization method is preferable. That is, the toner particles are preferably pulverized toner particles. Hereinafter, the toner manufacturing procedure by the pulverization method will be described.

[0087] The pulverization method includes, for example, a raw material mixing step of mixing a crystalline polyester C, an amorphous resin A, a phosphorus compound, and, if necessary, other components such as other amorphous resins, waxes, colorants, charge control agents, etc. as a binder resin, a step of melt-kneading the mixed raw materials to obtain a resin composition, and a step of pulverizing the obtained resin composition to obtain toner particles.

[0088] In the raw material mixing step, as materials constituting the toner particles, for example, a binder resin, a wax, and, if necessary, other components such as a colorant, a charge control agent, etc. are weighed and blended in predetermined amounts and mixed. Examples of mixing devices include a double con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, a Nauta mixer, a mechano hybrid (manufactured by Nippon Coke & Engineering Co., Ltd.), etc.

[0089] Next, the mixed materials are melt-kneaded to disperse the materials in the binder resin. In the melt-kneading step, a batch-type kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used. Due to the advantage of continuous production, a single-screw or twin-screw extruder has become the mainstream. For example, a KTK-type twin-screw extruder (manufactured by Kobe Steel, Ltd.), a TEM-type twin-screw extruder (manufactured by Toshiba Machine Co., Ltd.), a PCM kneader (manufactured by Ikegai Iron Works), a twin-screw extruder (manufactured by K.C.K. Co., Ltd.), a co-kneader (manufactured by Buss Co., Ltd.), a Neidex (manufactured by Nippon Coke & Engineering Co., Ltd.), etc. can be mentioned. Further, the resin composition obtained by melt-kneading may be rolled with a two-roll or the like and cooled with water or the like in a cooling step.

[0090] Then, the cooled resin composition is pulverized to a desired particle size in the pulverization step. In the pulverization step, first, for example, it is roughly pulverized with a pulverizer such as a crusher, a hammer mill, or a feather mill. Thereafter, it is finely pulverized with, for example, a Cryptron system (manufactured by Kawasaki Heavy Industries, Ltd.), a Super Rotor (manufactured by Nisshin Engineering Co., Ltd.), a turbo mill (manufactured by Turbo Industry), or a fine pulverizer using an air jet method.

[0091] After that, if necessary, classification is performed using a classifier or a sieve such as an elbow jet of the inertial classification method (manufactured by Nippon Steel Mining Co., Ltd.), a turbo plex of the centrifugal classification method (manufactured by Hosokawa Micron Corporation), a TSP separator (manufactured by Hosokawa Micron Corporation), or a faculty (manufactured by Hosokawa Micron Corporation).

[0092] After that, if necessary, an external additive such as silica fine particles is externally added to the surface of the toner particles to obtain a toner. Examples of the apparatus for external addition treatment include mixing apparatuses such as a double con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, a Nauta mixer, a mechano hybrid (manufactured by Nippon Coke & Engineering Co., Ltd.), and a Nobilta (manufactured by Hosokawa Micron Corporation). The measurement methods for various physical properties will be described below.

[0093] (Separation method of each material from toner) Each material can be separated from the toner by utilizing the difference in solubility of each material contained in the toner in a solvent or GPC. Using the separated each material, the following various physical properties can be measured.

[0094] First separation: Dissolve the toner in methyl ethyl ketone (MEK) at 23°C to separate the soluble components (amorphous resin A, amorphous resin B (used in the examples, the same applies hereinafter), crystalline polyester C, phosphorus compound) and the insoluble components (wax, colorant, inorganic fine particles, etc.).

[0095] Second separation: Dissolve the soluble components (amorphous resin A, amorphous resin B, crystalline polyester C, phosphorus compound) obtained in the first separation in tetrahydrofuran (THF) at 23°C to separate the soluble components (amorphous resin A, amorphous resin B, phosphorus compound) and the insoluble component (crystalline polyester C).

[0096] Third separation: Dissolve the insoluble components (wax, colorant, inorganic fine particles, etc.) obtained in the first separation in MEK at 100°C to separate the soluble component (wax) and the insoluble components (colorant, inorganic fine particles, etc.).

[0097] Fourth Separation: Dissolve the soluble components (amorphous resin A, amorphous resin B, phosphorus compound) obtained in the second separation in tetrahydrofuran (THF) at 23°C, and separate amorphous resin A, amorphous resin B, and the phosphorus compound by preparative GPC.

[0098] <Method for Confirming the Attribution and Measuring the Content Ratio of Various Monomer Units in Amorphous Resin and Crystalline Polyester> The confirmation of the attribution and the measurement of the content ratio of various monomer units in the amorphous resin and the crystalline polyester are 1 performed by 1H-NMR under the following conditions.

[0099] Measuring device: FT NMR device JNM-EX400 (manufactured by JEOL Ltd.) Measuring frequency: 400 MHz Pulse condition: 5.0 μs Frequency range: 10500 Hz Number of integrations: 64 times Measuring temperature: 30°C Sample: Put 50 mg of the measurement sample into a sample tube with an inner diameter of 5 mm, add deuterated chloroform (CDCl3) as a solvent, and dissolve it in a constant temperature bath at 40°C for preparation.

[0100] Obtained 1 From the obtained 1H-NMR chart, identify the structures of various monomer units, and calculate the integration values S1, S2, S3, ··· Sn of the peaks attributed to each monomer unit.

[0101] The content ratio of various monomer units is determined as follows using the above integration values S1, S2, S3, and Sn. Here, n1, n2, n3 ··· nn are the numbers of hydrogens in each monomer unit.

[0102] Content ratio of various monomer units (mol%) = { (S n / n n ) / ((S1 / n1) + (S2 / n2) + (S3 / n3) ··· + (S n / n n ))} × 100 Change the molecular terms of the same operation and calculate the content ratio (mol%) of each monomer unit. When a polymerizable monomer containing no hydrogen atom is used for each monomer unit, 13 Using C-NMR, set the measured nuclear to 13C and perform measurement in single pulse mode. 1 Calculate in the same manner using H-NMR.

[0103] <Method for calculating SP value of amorphous resin and crystalline polyester> The SP values of the amorphous resin and the crystalline polyester are calculated according to the calculation method proposed by Fedors.

[0104] Specifically, obtain the evaporation energy (Δei), molar volume (Δvi) for each monomer unit, and the molar ratio (j) in the resin. Using these, calculate the SP value from the following formula.

[0105] SP value (cal / cm 3 ) 0.5 ={(Σj×ΣΔei) / (Σj×ΣΔvi)} 0.5 For the evaporation energy (Δei) and molar volume (Δvi) of atoms or atomic groups in the monomer unit, use the values described in "polym.Eng.Sci., 14(2), 147 - 154(1974)".

[0106] <Content W of phosphorus element in toner P Measurement method> The content W P (ppm) of the phosphorus element in the toner is measured using a multi-element simultaneous ICP emission spectrometer Vista-PRO (manufactured by Hitachi High-Technologies Corporation).

[0107] Sample: 50 mg Solvent: 6 mL of nitric acid Weigh the above and perform decomposition treatment using a microwave sample pretreatment device ETHOS UP (manufactured by Milestone General). Temperature: Raise the temperature from 20°C to 230°C and hold at 230°C for 30 min After passing the decomposition solution through filter paper (5C), transfer it to a 50 mL volumetric flask and make up to 50 mL with ultrapure water. By measuring the aqueous solution in the volumetric flask with a multi-element simultaneous ICP emission spectrometer Vista-PRO under the following conditions, the phosphorus element content in the toner can be quantified. The quantification of the content is calculated based on the calibration curve prepared using a standard sample of the element to be quantified.

[0108] Conditions: RF power 1.20 kW, Ar gas: Plasma flow 15.0 L / min, Auxiliary flow: 1.50 L / min, MFC: 1.50 L / min, Nebulizer flow: 0.90 L / min, Liquid feed pump speed: 15 rpm, Measurement repetition: 3 times, Measurement time: 1.0 s

[0109] <Electrophotographic apparatus> The electrophotographic apparatus of the present disclosure is characterized by having the electrophotographic photoreceptor, toner, charging means, exposure means, developing means, transfer means, cleaning means, and fixing means described so far. FIG. 1 shows a process cartridge configuration including the electrophotographic photoreceptor of the present disclosure, and FIG. 2 shows an example of the schematic configuration of an electrophotographic apparatus having the process cartridge of FIG. 1. In FIG. 1, the cylindrical electrophotographic photoreceptor 1 is rotationally driven at a predetermined peripheral speed in the direction of the arrow. The peripheral surface of the rotationally driven electrophotographic photoreceptor 1 is uniformly charged to a positive or negative predetermined potential by the charging means 2. Next, the peripheral surface of the charged electrophotographic photoreceptor 1 receives image exposure light (image exposure light) 3 from an exposure means (not shown) such as slit exposure or laser beam scanning exposure. In this way, an electrostatic latent image corresponding to the target image is sequentially formed on the peripheral surface of the electrophotographic photoreceptor 1. As the voltage applied to the charging means (charging roller, etc.) 2, either a voltage obtained by superimposing an AC component on a DC component or a voltage of only a DC component may be used. The electrostatic latent image formed on the peripheral surface of the electrophotographic photoreceptor 1 is developed by toner contained in the developer of the developing means 4 to form a toner image. Next, the toner image formed and carried on the peripheral surface of the electrophotographic photoreceptor 1 is sequentially transferred to the transfer material (such as paper or an intermediate transfer body) 6 by the transfer bias from the transfer means (such as a transfer roller) 5. The transfer material 6 is fed in synchronization with the rotation of the electrophotographic photoreceptor 1. After the surface of the electrophotographic photoreceptor 1 after toner image transfer is discharged by the pre-exposure light 7 from the pre-exposure means (not shown), it is cleaned by removing residual transfer toner (residual toner) by the cleaning means 8 having a cleaning blade, and the electrophotographic photoreceptor 1 is repeatedly used for image formation. Note that the pre-exposure means may be before or after the cleaning step, and the pre-exposure means is not necessarily required. The electrophotographic photoreceptor 1 may be mounted on an electrophotographic apparatus such as a copying machine or a laser beam printer. Further, among the components such as the electrophotographic photoreceptor 1, the charging means 2, the developing means 4, and the cleaning means 8, a process cartridge 9 configured by housing a plurality of them in a container and supporting them integrally may be configured to be detachable from the electrophotographic apparatus main body. In FIG. 2, the electrophotographic photoreceptor 1, the charging means 2, the developing means 4, and the cleaning means 8 are integrally supported, and a process cartridge 9 that is detachable from the electrophotographic apparatus main body is shown.

[0110] Next, an electrophotographic apparatus provided with the electrophotographic photoreceptor of the present disclosure will be described. An example of the configuration of the electrophotographic apparatus of the present disclosure is shown in FIG. 2. The process cartridge 17 for yellow color, the process cartridge 18 for magenta color, the process cartridge 19 for cyan color, and the process cartridge 20 for black color corresponding to yellow color, magenta color, cyan color, and black color, respectively, are juxtaposed along the intermediate transfer body 10. The diameter, constituent material, developer, charging method, and other means of the electrophotographic photoreceptor do not necessarily have to be unified for each color. When the image forming operation starts, toner images of respective colors are sequentially superimposed on the intermediate transfer member 10 according to the above-described image forming process. In parallel, the transfer paper 11 is fed out from the paper feed tray 13 by the paper feed path 12 and fed to the secondary transfer means 14 in synchronization with the rotation operation of the intermediate transfer member. By the transfer bias from the secondary transfer means 14, the toner image on the intermediate transfer member 10 is transferred to the transfer paper 11. The toner image transferred onto the transfer paper 11 is conveyed along the paper feed path 12, fixed onto the transfer paper by the fixing means 15, and discharged from the paper discharge portion 16. The electrophotographic photoreceptor of the present disclosure can be used in a laser beam printer, an LED printer, a copying machine, a facsimile machine, and a multifunction machine thereof.

Example

[0111] Hereinafter, the present disclosure will be described in more detail using examples and comparative examples, but the present disclosure is not limited thereto. In the following description of the examples, "part" means based on mass unless otherwise specified.

[0112] 〔Manufacturing Example of Electrophotographic Photoreceptor 1〕 2 parts by mass of a polyamide resin (manufactured by Toray Industries, Inc., Amilan CM8000) was dissolved in a mixed solvent of 10 parts by mass of methyl ethyl ketone and 10 parts by mass of butanol. To this solution, 5 parts by mass of titanium oxide particles (trade name: TKP-101, manufactured by Teika Corporation, average primary particle diameter: 6 nm) coated with 10% of inorganic silica were added, and this was dispersed at 23 ± 3 °C in an atmosphere for 4 hours using a sand mill apparatus with glass beads having a diameter of 0.8 mm to prepare a coating liquid for an undercoat layer. The obtained coating liquid for the undercoat layer was dip-coated on an aluminum cylinder having a diameter of 30 mm and a length of 357.5 mm as a support to form a coating film, and the obtained coating film was dried at 130 °C for 30 minutes to form an undercoat layer having a film thickness of 2.0 μm. Next, a mixture consisting of 100 parts by mass of a polycarbonate resin represented by the following formula (C-1) as a binder resin, 70 parts by mass of a compound represented by the following formula (D-1) as a hole transport material, 30 parts by mass of a compound represented by the following formula (E-1) as an electron transport material, 10 parts by mass of a compound represented by the following formula (E-2), 2 parts by mass of a pigment represented by (G-1) as a charge generating material, 10 parts by mass of a compound represented by the following formula (F) as an additive, and 3 parts by mass of commercially available silica particles (number average primary particle diameter 12 nm, trade name: AEROSIL RX200, manufactured by Nippon Aerosil Co., Ltd.) as silicon atom-containing particles was dispersed for 8 hours in a sand mill using glass beads with a diameter of 1 mmφ to obtain a dispersion. The dispersion was passed through a 100-mesh filter (aperture 0.254 mm) to remove the glass beads, thereby obtaining a coating solution for the surface layer. This coating solution for the surface layer was dip-coated onto the undercoat layer, and the resulting coating film was dried at 110 °C for 50 minutes to form a surface layer with a film thickness of 30 μm. Through the above steps, an electrophotographic photoreceptor 1 was produced.

Chemical formula

[0113] 〔Manufacturing Examples of Electrophotographic Photoreceptors 2 to 25〕 Table 1 shows the types of silicon atom-containing particles used in electrophotographic photoreceptors 2 to 25.

[0114]

Table 1

[0115] The charge generating materials used in electrophotographic photoreceptors 11, 23, and 25 are shown by the following formula (G-2).

Chemical formula

[0116] In the formation of the surface layer, an electrophotographic photoreceptor was produced in the same manner as in the production example of the electrophotographic photoreceptor 1, except that the type and mass of the charge generating substance and the type and mass of the silicon atom-containing particles were changed as shown in Table 2.

[0117]

Table 2

[0118] [Production Example of Toner and Developer] <Measurement Method of Softening Point of Resin> The softening point of the resin is measured using a capillary rheometer of the constant load extrusion type (trade name: Flow Characteristic Evaluation Flow Tester CFT-500D, manufactured by Shimadzu Corporation) in accordance with the manual attached to the apparatus. In this apparatus, while applying a constant load to the piston from the upper part of the measurement material, the measurement sample filled in the cylinder is heated to melt, and the melted measurement sample is extruded from the die at the bottom of the cylinder, and a flow curve showing the relationship between the piston drop amount and the temperature at this time can be obtained. The "melting temperature in the 1 / 2 method" described in the manual attached to the "Flow Characteristic Evaluation Apparatus Flow Tester CFT-500D" is defined as the softening point. The melting temperature at 1 / 2 is calculated as follows. First, 1 / 2 of the difference between the piston drop amount (Smax) at the end of the outflow and the piston drop amount (Smin) at the start of the outflow is obtained (this is denoted as X. X = (Smax - Smin) / 2). Then, the temperature at which the piston drop amount in the flow curve becomes the sum of X and Smin is the melting temperature in the 1 / 2 method. As the measurement sample, about 1.0 g of resin is compression molded at about 10 MPa for about 60 seconds using a tablet molding compression machine (for example, NT-100H, manufactured by NPE System Co., Ltd.) in an environment of 25°C to form a columnar shape with a diameter of about 8 mm. The measurement conditions of the CFT-500D are as follows. Test mode: Heating method Start temperature: 50°C Reached temperature: 200°C Measurement interval: 1.0°C Heating rate: 4.0°C / min Piston cross-sectional area: 1.000 cm 2 Test load (piston load): 10.0 kgf / cm 2 (0.9807 MPa) Preheating time: 300 seconds Diameter of die hole: 1.0 mm Length of die: 1.0 mm

[0119] <Production Example of Resin 1> The following materials were charged into a reaction vessel equipped with a reflux condenser, stirrer, thermometer, and nitrogen inlet tube under a nitrogen atmosphere. · 100 parts by mass of propylene oxide adduct of bisphenol A (average number of moles of addition: 2.2 moles) · 21 parts by mass of recovered polyethylene terephthalate (diethylene glycol content = 1.3% by mass) · 0.08 parts by mass of dibutyltin oxide While stirring the inside of the reaction vessel at 200 rpm, it was heated to 230 °C and reacted for 7 hours. Subsequently, it was cooled to 180 °C, 30 parts by mass of fumaric acid and 0.08 parts by mass of hydroquinone were added, and it was heated to 210 °C over 4 hours. Then, the pressure was reduced to 8 kPa and reacted until the softening point reached 103 °C to obtain Resin 1.

[0120] <Production Example of Resin 2> The following materials were charged into a reaction vessel equipped with a reflux condenser, stirrer, thermometer, and nitrogen inlet tube under a nitrogen atmosphere. · 100 parts by mass of propylene oxide adduct of bisphenol A (average number of moles of addition: 2.2 moles) · 40 parts by mass of ethylene oxide adduct of bisphenol A (average number of moles of addition: 2.2 moles) · 13 parts by mass of dodecenyl succinic anhydride · 37 parts by mass of terephthalic acid · 12 parts by mass of trimellitic anhydride · 0.5 parts by mass of dibutyltin oxide While stirring the inside of the reaction vessel at 200 rpm, it was heated to 235 °C and reacted for 4 hours. Then, the pressure was reduced to 8 kPa and reacted until the softening point reached 146 °C to obtain Resin 2.

[0121] <Production Example of Toner Particles 1> · 70 parts by mass of Resin 1 · 30 parts by mass of Resin 2 · 7 parts by mass of Carbon Black R330R (manufactured by Cabot Corporation) · 0.5 parts by mass of Charge Control Agent Bontron P-51 (manufactured by Orient Chemical Industries Co., Ltd.) · 4 parts by mass of Release Agent Carnauba Wax No. 1 (manufactured by Kato Yoko Co., Ltd.) The above materials were mixed using a Henschel mixer (FM-75 type, manufactured by Nippon Coke Industry Co., Ltd.) at a rotation speed of 20 s-1 for a rotation time of 5 minutes, and then kneaded using a twin-screw kneader (PCM-30 type, manufactured by Ikegai Corporation) set at a temperature of 120°C and a screw rotation speed of 200 rpm at a discharge temperature of 135°C. The obtained kneaded material was cooled at a cooling rate of 15°C / min and coarsely pulverized to 1 mm or less using a hammer mill to obtain a coarsely pulverized product. The obtained coarsely pulverized product was finely pulverized using a mechanical pulverizer (T-250, manufactured by Freund Turbo Co., Ltd.). Further, classification was performed using a Faculity F-300 (manufactured by Hosokawa Micron Corporation) to obtain Toner Particles 1. The operating conditions were a classification rotor rotation speed of 130 s -1 and a dispersion rotor rotation speed of 120 s -1 as such.

[0122] [Production Example of Toner 1] The following materials were mixed using a Henschel mixer FM-10C type (manufactured by Nippon Coke Industry Co., Ltd.) at a rotation speed of 30 s -1 and a rotation time of 10 minutes to obtain Toner 1. · 100 parts by mass of Toner Particles 1 · 2.1 parts by mass of silica fine particles surface-treated with hexamethyldisilazane having an average particle diameter of 130 nm · 0.7 parts by mass of silica fine particles surface-treated with hexamethyldisilazane having an average particle diameter of 20 nm

[0123] <Production Example of Magnetic Carrier Core Particles 1> · 62.7 parts by mass of Fe2O3 · 29.5 parts by mass of MnCO3 · 6.8 parts by mass of Mg(OH)2 · 1.0 part by mass of SrCO3 The ferrite raw materials were weighed so that the above materials would have the above composition ratio. Thereafter, it was pulverized and mixed for 5 hours using a dry vibration mill with stainless steel beads. The obtained pulverized product was made into pellets of about 1 mm square using a roller compactor. Coarse powder was removed from this pellet using a vibrating sieve with a mesh size of 3 mm, and then fine powder was removed using a vibrating sieve with a mesh size of 0.5 mm. Thereafter, it was fired at 1000 °C for 4 hours in a nitrogen atmosphere (oxygen concentration: 0.01% by volume) using a burner-type firing furnace to produce a calcined ferrite. After the calcined ferrite was pulverized to about 0.3 mm using a crusher, 30 parts by mass of water was added to 100 parts by mass of the calcined ferrite using zirconia beads, and it was pulverized for 1 hour using a wet ball mill. Further, the obtained slurry was pulverized for 4 hours using a wet ball mill to obtain a ferrite slurry (a finely pulverized product of the calcined ferrite). To the ferrite slurry, 1.0 part by mass of ammonium polycarboxylate as a dispersant and 2.0 parts by mass of polyvinyl alcohol as a binder were added per 100 parts by mass of the calcined ferrite, and granulated into spherical particles using a spray dryer (manufacturer: Okawara Chemical Machinery Co., Ltd.). After adjusting the particle size of the obtained particles, it was heated at 650 °C for 2 hours using a rotary kiln to remove the organic components of the dispersant and the binder. To control the firing atmosphere, it was heated from room temperature to 1300 °C in 2 hours in a nitrogen atmosphere (oxygen concentration: 1.00% by volume) using an electric furnace, and then fired at 1150 °C for 4 hours. Thereafter, it was cooled to 60 °C over 4 hours, returned from the nitrogen atmosphere to the atmosphere, and taken out at a temperature of 40 °C or lower. After crushing the aggregated particles, low-magnetic products were cut by magnetic separation, and sieved using a sieve with a mesh size of 250 μm to remove coarse particles, thereby obtaining magnetic carrier core particles with a volume-based 50% particle size (D50) of 37.0 μm.

[0124] <Production Example of Magnetic Carrier 1> As the first coating step, a thermosetting silicone resin solution (methyl silicone resin) was applied to the magnetic carrier core particles. The amount of the coating resin was set to 0.20 parts by mass with respect to 100 parts by mass of the magnetic carrier core particles. For the application, a coating apparatus was used in which a rotary bottom plate disk and stirring blades were provided in a fluidized bed to form a swirling flow during the coating. The above-described resin solution was sprayed from a direction perpendicular to the moving direction in the fluidized bed apparatus. Next, the following materials were prepared. · Fluororesin solution (copolymer of tetrafluoroethylene and hexafluoropropylene (FEP)) (1.91 parts by mass as solid content with respect to 100 parts by mass of the magnetic carrier core particles) · Thermosetting melamine resin solution (0.09 parts by mass as solid content with respect to 100 parts by mass of the magnetic carrier core particles) These were thoroughly stirred and mixed to prepare a carrier coating solution. This coating solution was applied to the magnetic carrier core particles as the second coating step. For the application, a coating apparatus was used in which a rotary bottom plate disk and stirring blades were provided in a fluidized bed to form a swirling flow during the coating. Thereafter, the obtained carrier was dried in the fluidized bed at a temperature of 280 °C for 1 hour to remove the solvent, and magnetic carrier 1 was obtained.

[0125] [Production Example of Developer 1] The following materials were mixed by a V-type mixer (V-20, manufactured by Seishin Enterprise Co., Ltd.) to obtain developer 1. · 8 parts by mass of toner 1 · 92 parts by mass of magnetic carrier 1

[0126] [Example 1] As an electrophotographic apparatus, an electrophotographic apparatus iR-ADVC5255 manufactured by Canon was used as a base, and it was modified for the positive charging process and further modified as follows to prepare an electrophotographic apparatus. Electrophotographic photoreceptor 1 was mounted on the black station of the prepared electrophotographic apparatus, and developer 1 was set in the developing device as the developer.

[0127] [Evaluation 1: Evaluation of Pattern Memory] The above electrophotographic apparatus was placed in an environment of 32.5°C / 85%RH, and the conditions of the charging device and the exposure device were set so that the charging potential of the electrophotographic photoreceptor was +600V and the exposure potential was +200V, and the conditions of the developing device were set so that the developing potential was +400V. As the pattern image to be output, a pattern image having an image with a width of 10 mm and a length of 200 mm in a direction parallel to the paper feed direction was prepared. Next, using A4-sized plain paper, the above pattern image was output continuously 5000 times as a solid image with a density of 100% in black single color. Subsequently, when one full-page halftone image with a density of 30% in black single color was output, it was evaluated whether a density difference occurred in the image portion with a width of 10 mm and a length of 200 mm output previously. The output images were evaluated according to the following evaluation criteria. The evaluation results are shown in Table 3. (Evaluation Criteria for Pattern Memory) A: No density difference occurs B: A density difference at a level where it cannot be determined whether it exists occurs C: A slight density difference occurs (acceptable level in the present invention) D: A distinct density difference occurs (unacceptable level in the present invention)

[0128] [Evaluation 2: Evaluation of Potential Fluctuation during Repeated Use] The above electrophotographic apparatus was installed in an environment of 23°C / 50%RH, and the conditions of the charging device and the exposure device were set so that the charging potential of the electrophotographic photoreceptor was +600V and the exposure potential was +200V, and the conditions of the developing device were set so that the developing potential was +400V. Using A4-sized plain paper, a character image with a printing rate of 1% in black single color was formed 10000 times repeatedly at the black station where the electrophotographic photoreceptor was installed. The initial exposure potential was compared with the exposure potential after 10000 times of repeated image formation, and this was taken as the value of potential fluctuation (ΔVl). After passing 10000 sheets of paper, it was left for 5 minutes, the developing cartridge was replaced with a potential measuring device, and the exposure potential (Vlb) after repeated use was measured. The difference between the exposure potential after repeated use and the initial exposure potential (Vla) was taken as the exposure potential fluctuation amount (ΔVl = |Vlb| - |Vla|). Table 3 shows the results of evaluation according to the following evaluation criteria. (Evaluation criteria for ΔVl) A: ΔVl is 0 V or more and less than 30 V (excellent) B: ΔVl is 30 V or more and less than 40 V (somewhat excellent) C: ΔVl is 40 V or more and less than 50 V (acceptable level in the present invention) D: ΔVl is 50 V or more (unacceptable level in the present invention)

[0129] [Examples 2 to 23, Comparative Examples 1 to 2] The electrophotographic apparatus was evaluated in the same manner as in Example 1 except that the type of the electrophotographic photoreceptor was changed as shown in Table 3. Table 3 shows the evaluation results.

[0130] [Table 3]

[0131] [Production Example 2 of Toner] [Preparation of Amorphous Resin A1] · Polyethylene terephthalate (molecular weight: 2000, intrinsic viscosity: 0.1): 20.9 parts (42.0 mol%) · Propylene oxide adduct of bisphenol A (average number of added moles 2.0 mol): 47.4 parts (29.0 mol%) · Terephthalic acid: 15.8 parts (18.3 mol%) · Dodecenyl succinic anhydride: 15.8 parts (10.6 mol%) · Titanium tetrabutoxide (esterification catalyst): 0.5 part · Gallic acid (promoter): 0.1 part The above materials were weighed into a reaction vessel equipped with a cooling pipe, a stirrer, a nitrogen inlet pipe, and a thermocouple. The molar ratio of polyethylene terephthalate is a value based on the total number of units derived from ethylene glycol units and terephthalic acid units. Furthermore, the pressure in the reaction vessel was reduced to 8.3 kPa, and the reaction was carried out for 5 hours while maintaining the temperature at 200 °C. After confirming that the weight average molecular weight reached 6,700, the temperature was lowered to stop the reaction, and an amorphous resin A1 having a polyethylene terephthalate segment in the molecule was obtained. The physical properties of the amorphous resin A1 obtained by the above-described measurement method are shown in Table 4.

[0132] <Preparation of Amorphous Resins A2 to A11> In the preparation of the amorphous resin A1, the reaction was carried out in the same manner except that the types and amounts of the polyethylene terephthalate and the polymerizable monomers were changed to those shown in Tables 4-1 to 4-2, and amorphous resins A2 to A11 having a polyethylene terephthalate segment in the molecule were obtained. The physical properties of the amorphous resins A2 to A11 obtained by the above-described measurement method are shown in Tables 4-1 to 4-2.

[0133]

Table 4-1

[0134]

Table 4-2

[0135] The abbreviations in Table 4 are as follows. BPA-PO: Propylene oxide adduct of bisphenol A (average number of added moles: 2.0 mol) BPA-EO: Ethylene oxide adduct of bisphenol A (average number of added moles: 2.0 mol)

[0136] <Preparation of Amorphous Resin B1> · Polyethylene terephthalate (molecular weight: 2,000, intrinsic viscosity: 0.1): 4.1 parts (9.8 mol%) · Propylene oxide adduct of bisphenol A (average number of added moles: 2.0 mol): 57.8 parts (42.8 mol%) · Terephthalic acid: 29.9 parts (41.9 mol%) · Trimellitic acid: 7.0 parts (4.5 mol%) · Stearic acid: 1.2 parts (1.0 mol%) · Titanium tetrabutoxide (esterification catalyst): 0.5 part · Gallic acid (promoter): 0.1 part The above materials were weighed into a reaction vessel equipped with a condenser, a stirrer, a nitrogen inlet tube, and a thermocouple. Next, after purging the inside of the flask with nitrogen gas, the temperature was gradually increased with stirring, and the reaction was carried out for 2 hours while stirring at a temperature of 200 °C. Furthermore, the pressure inside the reaction vessel was reduced to 8.3 kPa, and the reaction was carried out for 5 hours while maintaining the temperature at 200 °C. After confirming that the weight-average molecular weight had reached 1000, the temperature was lowered to stop the reaction, and an amorphous resin B1 was obtained. The physical properties of the amorphous resin B1 obtained by the above-described measurement method were an SP value of 11.54 (cal / cm 3 ) 0.5 and it was like this.

[0137] <Production of crystalline polyester C1> · Ethylene glycol: 10.2 parts (48.2 mol%) · Tetradecanedioic acid: 81.3 parts (48.3 mol%) · Behenic acid: 8.5 parts (3.5 mol%) · Titanium tetrabutoxide (esterification catalyst): 0.5 part The above materials were weighed into a reaction vessel equipped with a condenser, a stirrer, a nitrogen inlet tube, and a thermocouple. Next, after purging the inside of the flask with nitrogen gas, the temperature was gradually increased with stirring, and the reaction was carried out for 2 hours while stirring at a temperature of 200 °C. Furthermore, the pressure inside the reaction vessel was reduced to 8.3 kPa, and the reaction was carried out for 5 hours while maintaining the temperature at 200 °C. After that, the temperature was lowered to stop the reaction, and a crystalline polyester C1 was obtained. The physical properties of the crystalline polyester C1 obtained by the above-described measurement method were an SP value of 10.09 (cal / cm 3 ) 0.5 and it was like this.

[0138] <Production Example of Toner 2> · Amorphous resin A1: 66 parts · Amorphous resin B1: 34 parts · Crystalline polyester C1: 10 parts · Fischer-Tropsch wax (peak temperature of the maximum endothermic peak: 100 °C): 5 parts · Carbon black: 5 parts · Sodium phosphate: 0.160 part · Charge control agent, Bontron P-51 (manufactured by Orient Chemical Industries Co., Ltd.): 0.5 part The above materials were mixed using a Henschel mixer (FM-75 type, manufactured by Mitsui Mining Co., Ltd.) at a rotation speed of 1500 rpm for 5 minutes, and then kneaded using a twin-screw kneader (PCM-30 type, manufactured by Ikegai Corporation) set at a temperature of 130 °C. The obtained kneaded product was cooled and roughly pulverized to 1 mm or less using a hammer mill to obtain a roughly pulverized product. The obtained roughly pulverized product was finely pulverized using a mechanical pulverizer (T-250, manufactured by Turbo Industry Co., Ltd.). Further, classification was performed using a Faculte (F-300, manufactured by Hosokawa Micron Corporation) to obtain toner particles 2. The operating conditions were a classification rotor rotation speed of 11000 rpm and a dispersion rotor rotation speed of 7200 rpm. · Toner particles 2: 95 parts · Inorganic fine particles with a large particle size: 4 parts of fumed silica surface-treated with hexamethyldisilazane (median diameter (D50) based on the number of particles is 120 nm) · Inorganic fine particles with a small particle size: 1 part of titanium oxide fine particles surface-treated with isobutyltrimethoxysilane (median diameter (D50) based on the number of particles is 10 nm) The above materials were mixed using a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Machinery Co., Ltd.) at a rotation speed of 1900 rpm for 10 minutes to obtain toner 2 showing positive chargeability. The physical properties of toner 2 obtained by the above-described measurement method are shown in Table 5.

[0139] <Production Examples of Toners 3 to 19> In the production example of toner 3, the same operations as in the production example of toner 2 were performed except that the types and amounts of the amorphous resin A and additives were changed as shown in Table 5 to obtain toners 3 to 19. The physical properties of toners 3 to 19 obtained by the above-described measurement method are shown in Table 5.

[0140]

Table 5

[0141] The abbreviations in Table 5 are as follows. PNa: Trisodium phosphate PF: Triphenyl phosphate

[0142] <Production Examples of Developers 2 to 19> In the production example of Developer 1, the same operations were performed except that the changes were made as shown in Table 6, and Developers 2 to 19 were obtained.

[0143]

Table 6

[0144] [Examples 24 to 41] The electrophotographic apparatus was evaluated in the same manner as in Example 1 except that the types of the electrophotographic photoreceptor and the developer were changed as shown in Table 7. Further, the evaluation of scratch resistance and low-temperature fixability was also performed by the methods shown below. The evaluation results are shown in Table 7.

[0145] [Evaluation of Scratch Resistance / Low-Temperature Fixability] As the image forming apparatus, a modified machine of the Canon digital commercial printer imagePress C800 for digital commercial printing was used. The electrophotographic photoreceptor 12 was mounted on the cyan station, and the developer 2 was set in the developing device of the cyan station. As the modification points of the apparatus, the fixing temperature, the process speed, the DC voltage V of the developer carrier DC , the charging voltage V of the electrophotographic photoreceptor D , and the laser power were changed so that they could be freely set. For the image output evaluation, an FFh image (solid image) with a desired image ratio was output, and V was adjusted so that the toner loading amount on the FFh image on the paper became as desired DC , V D , and the laser power, and the evaluation of scratch resistance and low-temperature fixability described below was performed. FFh is a value representing 256 gradations in hexadecimal notation, where 00h is the first gradation (white background part) of 256 gradations, and FFh is the 256th gradation (solid part) of 256 gradations.

[0146] [Evaluation 3: Scratch resistance] Paper: UPM FINESSE GLOSS 300GSM Toner loading amount on paper: 0.05 mg / cm 2 (2Fh image) (The toner loading amount is adjusted by the DC voltage V of the developer carrier DC , the charging voltage V of the electrophotographic photoreceptor D , and the laser power. The charging voltage V of the electrophotographic photoreceptor D was set to positive charging.) Evaluation image: Place a 3 cm × 15 cm image in the center of the above A4 paper Fixing test environment: Normal temperature and humidity environment (temperature 23°C / humidity 50% RH (hereinafter N / N)) Fixing temperature: 180°C Process speed: 377 mm / sec The above evaluation image was output and the scratch resistance was evaluated. Specifically, using a surface property tester HEIDON TYPE14FW manufactured by Shinto Kagaku Co., Ltd., a 200 g weight was placed, and scratching was performed with a needle having a diameter of 0.75 mm at a speed of 60 mm / min and a length of 30 mm, and the evaluation was made based on the scratches generated on the image. The area ratio of the peeled toner was obtained by binarizing the area where the toner peeling occurred with respect to the scratched area by image processing.) (Evaluation criteria) A: 0.0% B: 0.1% or more and less than 1.1% C: 1.1% or more

[0147] [Evaluation 4: Low-temperature fixing property] Paper: GFC-081 (81.0 g / m 2 )(Sold by Canon Marketing Japan Inc.) Toner loading amount on paper: 0.50 mg / cm 2 (The toner loading amount is adjusted by the DC voltage V of the developer carrier DC , the charging voltage V of the electrophotographic photoreceptor D , and the laser power. The charging voltage V of the electrophotographic photoreceptor D was set to positive charging.) Evaluation image: Place a 2 cm × 5 cm image in the center of the above A4 paper Test environment: Low temperature and low humidity environment: Temperature 15°C / Humidity 10%RH (hereinafter referred to as "L / L") Fixing temperature: 150°C, Process speed: 630 mm / sec The above evaluation image was output, and the low-temperature fixing property was evaluated. The value of the reduction rate of image density was used as an evaluation index for the low-temperature fixing property. Using an X-Rite color reflection densitometer (500 series: manufactured by X-Rite), first, the image density at the center was measured. Next, a load of 4.9 kPa (50 g / cm 2 ) was applied to the fixed image by a silicone paper for friction (5 reciprocations), and the image density was measured again. Then, the reduction rate of the image density before and after friction was calculated using the following formula. The obtained reduction rate of the image density was evaluated according to the following evaluation criteria. If the evaluation was A to C, it was judged to be good. Reduction rate of image density (%) = (Image density before friction - Image density after friction) / Image density before friction × 100 (Evaluation criteria) A: Reduction rate of image density less than 3% B: Reduction rate of image density 3% or more and less than 10% C: Reduction rate of image density 10% or more

[0148]

Table 7

[0149] The toner used in the electrophotographic apparatus of the present disclosure can use polyethylene terephthalate regenerated from used PET bottles, etc. as a toner material, so the technology described in this specification can contribute to the realization of a sustainable society such as a decarbonized / circular society.

[0150] The disclosure of this embodiment includes the following configurations. [Configuration 1] An electrophotographic photoreceptor, Charging means for charging the surface of the electrophotographic photoreceptor, Image exposure means for irradiating the surface of the charged electrophotographic photoreceptor with image exposure light to form an electrostatic latent image on the surface of the electrophotographic photoreceptor, Developing means for forming a toner image on the surface of the electrophotographic photoreceptor by developing the electrostatic latent image with the toner, Transfer means for transferring the toner image from the surface of the electrophotographic photoreceptor to a transfer material, Cleaning means for removing residual toner remaining on the surface of the electrophotographic photoreceptor after transferring the toner image from the surface of the electrophotographic photoreceptor to the transfer material using a cleaning blade, Fixing means for fixing the toner image transferred to the transfer material to the transfer material, and an electrophotographic apparatus having the same, The electrophotographic photoreceptor has a single-layer photosensitive layer containing a binder resin, a charge generating substance, a hole transporting substance, an electron transporting substance, and silicon atom-containing particles, The single-layer photosensitive layer is the surface layer of the electrophotographic photoreceptor, The charge generating substance is metal-free phthalocyanine or oxytitanium phthalocyanine, The silicon atom-containing particles are silica particles or silicone resin particles, The toner has toner particles containing a polyester resin having a polyethylene terephthalate segment, and an electrophotographic apparatus characterized by this. [Configuration 2] The electrophotographic apparatus according to Configuration 1, wherein the content of the silicon atom-containing particles in the surface layer is 0.1% by mass or more and 10.0% by mass or less based on the total mass of the surface layer. [Configuration 3] The electrophotographic apparatus according to 1 or 2, wherein the content of the silicon atom-containing particles in the surface layer is 10% by mass or more and 1400% by mass or less based on the content of the charge generating substance in the surface layer. [Configuration 4] The electrophotographic apparatus according to any one of Configurations 1 to 3, wherein the number average primary particle diameter of the silicon atom-containing particles is 10 nm or more and 2000 nm or less. [Configuration 5] The electrophotographic apparatus according to any one of Configurations 1 to 4, wherein the silicon atom-containing particles are silicone resin particles. [Configuration 6] The toner is a toner having toner particles containing a binder resin, the binder resin contains an amorphous resin A and a crystalline polyester C, and the amorphous resin A is the polyester resin, and as a structure forming a polyester skeleton, (i) the polyethylene terephthalate segment, and (ii) at least one structure selected from the group consisting of units represented by the following formulas (1) to (4), [Chemical formula] (In the formula, R 1 represents an alkyl group having 6 to 16 carbon atoms or an alkenyl group having 6 to 16 carbon atoms, A represents a hydrocarbon group, * represents a bonding portion in the polyester skeleton, and m represents an integer of 2 or more.) [Chemical formula] (In the formula, R 2 represents an alkyl group having 6 to 16 carbon atoms or an alkenyl group having 6 to 16 carbon atoms, B represents a hydrocarbon group, * represents a bonding portion in the polyester skeleton, and n represents an integer of 2 or more.) [Chemical formula] (In the formula, * represents a bonding portion in the polyester skeleton, and x represents an integer of 6 to 16.) [Chemical formula] (In the formula, * represents a bonding portion in the polyester skeleton, and y represents an integer of 6 to 16.) When the SP value of the amorphous resin A is SP A (cal / cm 3 ) 0.5 and the SP value of the crystalline polyester C is SP C (cal / cm 3 ) 0.5 when, the SP A and the SP C satisfy the following formula (C), 1.00 ≦ SP A—SP C ≤1.35 ··· (C) The toner contains phosphorus element derived from a phosphorus compound, and the content of the phosphorus element in the toner based on the mass of the toner is W P (ppm), when the W P satisfies the following formula (D), the electrophotographic apparatus according to any one of Configurations 1 to 5 5 ≤ W P ≤ 500 ··· (D) [Configuration 7] The electrophotographic apparatus according to Configuration 6, wherein the W P satisfies the following formula (E). 20 ≤ W P ≤ 500 ··· (E)

Explanation of Signs

[0151] 1 Electrophotographic photoreceptor 2 Charging means 3 Image exposure light 4 Developing means 5 Transfer means 6 Transfer material 7 Pre-exposure light 8 Cleaning means 9 Process cartridge 10 Intermediate transfer member 11 Transfer paper 12 Paper feed path 13 Paper feed tray 14 Secondary transfer means 15 Fixing means 16 Paper discharge section 17 Process cartridge for yellow color 18 Process cartridge for magenta color 19 Process cartridge for cyan color 20 Process cartridge for black color

Claims

1. An electrophotographic photoreceptor, charging means for charging the surface of the electrophotographic photoreceptor, image exposure means for irradiating image exposure light onto the surface of the charged electrophotographic photoreceptor to form an electrostatic latent image on the surface of the electrophotographic photoreceptor, developing means having toner and developing the electrostatic latent image with the toner to form a toner image on the surface of the electrophotographic photoreceptor, transfer means for transferring the toner image from the surface of the electrophotographic photoreceptor to a transfer material, cleaning means for removing residual toner remaining on the surface of the electrophotographic photoreceptor after transferring the toner image from the surface of the electrophotographic photoreceptor to the transfer material using a cleaning blade, fixing means for fixing the toner image transferred to the transfer material to the transfer material, an electrophotographic apparatus comprising: the electrophotographic photoreceptor has a single-layer photosensitive layer containing a binder resin, a charge generating substance, a hole transporting substance, an electron transporting substance, and silicon atom-containing particles, the single-layer photosensitive layer is the surface layer of the electrophotographic photoreceptor, the charge generating substance is metal-free phthalocyanine or oxytitanium phthalocyanine, the silicon atom-containing particles are silica particles or silicone resin particles, the toner has toner particles containing a polyester resin having a polyethylene terephthalate segment, an electrophotographic apparatus characterized by this.

2. The electrophotographic apparatus according to claim 1, wherein the content of the silicon atom-containing particles in the surface layer is 0.1% by mass or more and 10.0% by mass or less based on the total mass of the surface layer.

3. The electrophotographic apparatus according to claim 1, wherein the content of the silicon atom-containing particles in the surface layer is 10% by mass or more and 1400% by mass or less based on the content of the charge generating substance in the surface layer.

4. The electrophotographic apparatus according to claim 1, wherein the number average primary particle diameter of the silicon atom-containing particles is 10 nm or more and 2000 nm or less.

5. The electrophotographic apparatus according to any one of claims 1 to 4, wherein the silicon atom-containing particles are silicone resin particles.

6. The toner is a toner having toner particles containing a binder resin, the binder resin contains an amorphous resin A and a crystalline polyester C, and the amorphous resin A is the polyester resin and has a structure forming a polyester backbone, (i)the polyethylene terephthalate segment, and (ii) having at least one structure selected from the group consisting of units represented by the following formulas (1) to (4), 【Chemical Formula 1】 (In the formula, R １ represents an alkyl group having 6 to 16 carbon atoms or an alkenyl group having 6 to 16 carbon atoms, A represents a hydrocarbon group, * represents a bonding part in the polyester skeleton, and m represents an integer of 2 or more.) [Chemical Formula 2] (wherein, R ２ represents an alkyl group having 6 to 16 carbon atoms or an alkenyl group having 6 to 16 carbon atoms, B represents a hydrocarbon group, * represents a bonding portion in the polyester skeleton, and n represents an integer of 2 or more.) 【Chemical Formula 3】 (In the formula, * represents a bonding portion in the polyester skeleton, and x represents an integer of 6 to 16.) 【Chemical 4】 (In the formula, * represents a bonding portion in the polyester skeleton, and y represents an integer of 6 to 16.) When the SP value of the amorphous resin A is SP Ａ (cal / cm ３ ) ０．５ , and the SP value of the crystalline polyester C is SP Ｃ (cal / cm ３ ), ０．５ when the SP Ａ and the SP Ｃ satisfy the following formula (C), 1.00 ≤ SP Ａ -SP Ｃ ≤ 1.35... (C) the toner contains a phosphorus element derived from a phosphorus compound, When the content of the phosphorus element in the toner is W (ppm) based on the mass of the toner, Ｐ the electrophotographic apparatus according to any one of claims 1 to 4, characterized in that the W Ｐ satisfies the following formula (D). 5 ≤ W Ｐ ≤ 500... (D)

7. The aforesaid W Ｐ The electrophotographic apparatus according to claim 6, wherein W satisfies the following formula (E). 20 ≤ W Ｐ ≤ 500 ··· (E)

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