Process cartridges and electrophotographic devices

Abstract

To provide a process cartridge that has a long service life and prevents an increase in driving torque during repeated high-speed use.SOLUTION: A process cartridge has an electrophotographic photoreceptor, toner, and a developing member. The electrophotographic photoreceptor has a surface layer that is a polymer film of a composition containing at least one monofunctional (meth)acrylic compound selected from the group consisting of a monofunctional (meth)acrylic monomer and a monofunctional (meth)acrylic oligomer, and at least one tri- or more functional (meth)acrylic compound selected from the group consisting of a tri- or more functional (meth)acrylic monomer and a tri- or more functional (meth)acrylic oligomer. The toner has toner particles and hydrotalcite particles as an external additive. In filter fitting analysis in STEM-EDS analysis, the hydrotalcite particles contain fluorine. The process cartridge can be attached to and detached from the main body of an electrophotographic device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In recent years, electrophotographic equipment has been required to be smaller and less expensive, in parallel with efforts to extend lifespan and increase speed. However, in the electrophotographic process, extending lifespan and increasing speed tend to cause various problems, and adding components and control units to counteract these problems makes the electrophotographic equipment larger and more expensive. Therefore, in order to achieve both extended lifespan and high speed, as well as miniaturization and low cost, various measures have been taken to address these problems.

[0003] Among the aforementioned drawbacks is the problem that the power required to drive the electrophotographic photoreceptor (hereinafter also referred to as the "photoreceptor") mounted in an electrophotographic device increases with repeated use. A large increase in power necessitates a more powerful drive unit from the outset, resulting in large and expensive electrophotographic devices. Since the drive power is proportional to the drive torque of the photoreceptor, recent photoreceptors are required to suppress the increase in drive torque during repeated use.

[0004] Patent Document 1 describes an image forming method in which the amount of inorganic lubricant supplied to the surface of a photoreceptor increases in accordance with the number of charging histories of the photoreceptor due to repeated use. In order to achieve a long lifespan, if a protective layer made of cross-linked curing resin is provided on the surface of the photoreceptor to provide high durability, the rate of deterioration of the photoreceptor surface due to charging becomes greater than the rate of surface wear, and the driving torque increases due to the discharge products that adhere to it. To suppress this increase in driving torque, the driving torque can be reduced by supplying lubricant to the surface of the photoreceptor to form a lubricant film.

[0005] Patent Document 2 describes an image forming apparatus having a photoreceptor on which a protective layer is formed on the surface, obtained by curing a monofunctional (meth)acrylic polymerizable compound having a charge transport structure and a trifunctional or more functional (meth)acrylic monomer that does not have a charge transport structure, and a heater installed inside the photoreceptor. By curing a monofunctional monomer and a trifunctional or more functional monomer, a three-dimensional network structure is developed and the crosslinking density is increased, resulting in a protective layer that is highly hard, highly elastic, and highly smooth. Furthermore, by using a heater to reduce the humidity on the surface of the photoreceptor, the increase in moisture adsorption to the surface due to the low amount of wear on the protective layer can be suppressed, and image blurring (also called "image blur") can be prevented.

[0006] Patent Document 3 describes an image forming apparatus comprising a photoreceptor with a fluorine-containing surface protective layer, a detection means for detecting the frictional resistance of the photoreceptor surface, and polishing and control means for changing the conditions for polishing the photoreceptor surface according to the detection result. By containing fluorine in the protective layer, the hydrophobicity of the photoreceptor surface is increased, and image flow can be suppressed without the need for a heater. Furthermore, even if repeated use leads to the adhesion of discharge products to the photoreceptor surface and oxidative degradation, causing moisture to be adsorbed to an extent that cannot be suppressed by fluorine alone, or if fluorine is not uniformly contained in the thickness direction of the protective layer, image flow can be reliably suppressed by the above-mentioned detection means, polishing means, and control means. In addition, to detect this frictional resistance, the driving torque of the photoreceptor can be measured by measuring the current value of the drive motor.

[0007] Patent Document 4 describes an image forming method in which a developer containing a hydrotalcite compound is supplied to the surface of a photoreceptor. The anion exchange properties of the hydrotalcite compound in the developer exert an acid-receiving effect, which effectively removes discharge products without incorporating new and complex equipment and suppresses the adsorption of moisture in the atmosphere. It is also disclosed that a certain degree of wear of the surface layer can suppress the renewal of the deteriorated surface and the progression of the adhesion of discharge products to the surface.

[0008] Patent Document 5 describes an image forming apparatus having a photoreceptor having a protective layer cured from a (meth)acrylic polymerizable compound with one functional group and a (meth)acrylic polymerizable compound with three or more functional groups, and a developing means containing a two-dimensional layer structure, such as a hydrotalcite compound, together with toner as an inorganic lubricant. The protective layer may also contain fluororesin powder or metal fluoride as a filler. These combinations stably achieve effects such as improved abrasion resistance, scratch resistance, and cleanability, as well as suppression of image blurring and filming, even with repeated use.

[0009] Patent document 6 describes a semiconductor member for image formation having hydrotalcite, fluorine-based polymer nanoparticles, and acrylic resin. By using this semiconductor member as at least one of a charging means and a transfer means, the adhesion of paper dust and toner to the surface of the semiconductor member can be suppressed. Furthermore, by suppressing bleeding from the semiconductor member, photoreceptor contamination can be prevented, environmental fluctuations can be suppressed and image quality degradation can be eliminated without impairing conductivity, lubricity can be improved, and wear resistance and durability can be improved.

[0010] Patent Document 7 describes an electrophotographic apparatus in which at least the tip edge of a rubbery elastic cleaning blade is coated with a fluorinated graphite and hydrotalcite compound. Even if the apparatus is installed in a high-temperature environment for a long time, the hydrotalcite adsorbs fluorine anions generated from the fluorinated graphite by ion exchange, thereby reducing frictional resistance between the cleaning blade and the photoreceptor and improving cleaning performance without adversely affecting the image. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2016-156977 [Patent Document 2] Japanese Patent Publication No. 2006-250989 [Patent Document 3] Japanese Patent Application Laid-Open No. 2011-158790 [Patent Document 4] Japanese Patent Application Laid-Open No. 2003-66637 [Patent Document 5] Japanese Patent Application Laid-Open No. 2012-27091 [Patent Document 6] Japanese Patent Application Laid-Open No. 2008-129481 [Patent Document 7] Japanese Patent Application Laid-Open No. 3-152588 [Summary of the Invention] [Problems to be Solved by the Invention]

[0012] According to the studies by the present inventors, in the technologies described in Patent Documents 1 to 7, neither the type of the substance for reducing the driving torque existing on the photoreceptor nor the change in the amount of the substance for reducing the driving torque in repeated use was optimized. Therefore, without increasing the size or cost of the electrophotographic apparatus by adding members or a control unit, in various temperature and humidity environments from low temperature and low humidity to high temperature and high humidity, and without depending on various potential settings such as the charging unit and the transfer unit, it has been a problem to suppress the increase in the driving torque during long-life and high-speed repeated use.

[0013] Therefore, an object of the present invention is to provide a process cartridge that suppresses an increase in the driving torque during long-life and high-speed repeated use without increasing the size or cost of the electrophotographic apparatus by adding members or a control unit, and without depending on various temperature and humidity environments from low temperature and low humidity to high temperature and high humidity, and various potential settings such as the charging unit and the transfer unit. [Means for Solving the Problems]

[0014] The above objectives are achieved by the present invention as follows. Specifically, the process cartridge according to the present invention is a process cartridge that is detachably attached to the body of an electrophotographic apparatus, and the process cartridge comprises an electrophotographic photoreceptor, toner, and a developing member that supplies the toner to the electrophotographic photoreceptor, wherein the electrophotographic photoreceptor has a surface layer that is a polymerized film of a composition containing at least one monofunctional (meth)acrylic compound selected from the group consisting of monofunctional (meth)acrylic monomers and monofunctional (meth)acrylic oligomers, and at least one trifunctional or more (meth)acrylic compound selected from the group consisting of trifunctional or more (meth)acrylic monomers and trifunctional or more (meth)acrylic oligomers, and the toner comprises toner particles and hydrotalcite particles as an external additive, and the hydrotalcite particles are characterized in that they contain fluorine in filter fitting analysis in STEM-EDS analysis. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a process cartridge that has a long lifespan and suppresses the increase in drive torque during high-speed repeated use, without increasing the size or cost of the electrophotographic apparatus by adding components or control units, and without depending on various temperature and humidity environments from low temperature and low humidity to high temperature and high humidity, as well as various potential settings such as the charging section and transfer section. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram showing an example of an electrophotographic apparatus having a process cartridge equipped with an electrophotographic photoreceptor, toner, and a developing component. [Figure 2] (a): Schematic diagram of line analysis in STEM-EDS analysis. (b): An example of X-ray intensity of fluorine and aluminum obtained by line analysis. (c): Another example of X-ray intensity of fluorine and aluminum obtained by line analysis. [Modes for carrying out the invention]

[0017] The present invention will be described in detail below with reference to preferred embodiments. The present invention relates to a process cartridge that is detachably attached to the body of an electrophotographic apparatus, wherein the process cartridge comprises an electrophotographic photoreceptor, toner, and a developing member that supplies the toner to the electrophotographic photoreceptor, wherein the electrophotographic photoreceptor has a surface layer that is a polymerized film of a composition containing at least one monofunctional (meth)acrylic compound selected from the group consisting of monofunctional (meth)acrylic monomers and monofunctional (meth)acrylic oligomers, and at least one trifunctional or more (meth)acrylic compound selected from the group consisting of trifunctional or more (meth)acrylic monomers and trifunctional or more (meth)acrylic oligomers, wherein the toner comprises toner particles and hydrotalcite particles as an external additive, and the hydrotalcite particles contain fluorine in filter fitting analysis in STEM-EDS analysis. Furthermore, the present invention relates to an electrophotographic apparatus characterized by having the above-mentioned process cartridge.

[0018] The inventors found that adding components and control units from the conventional technology led to an increase in the size and cost of the electrophotographic device. Furthermore, the conventional drive torque reducing material was not optimized in terms of its type and the changes in its quantity during repeated use. As a result, it was insufficient to suppress the increase in drive torque during long-life, high-speed repeated use, regardless of various temperature and humidity environments from low temperature and low humidity to high temperature and high humidity, or various potential settings such as the charging section and transfer section.

[0019] Therefore, the inventors have found that in order to optimize the combination of the photoreceptor and toner and solve the above problem, the photoreceptor and toner should be designed and combined as follows.

[0020] <Design of the photoreceptor> The electrophotographic photoreceptor according to the present invention must have a surface layer formed by polymerizing a composition containing at least one monofunctional (meth)acrylic compound selected from the group consisting of monofunctional (meth)acrylic monomers and monofunctional (meth)acrylic oligomers, and at least one trifunctional or more (meth)acrylic compound selected from the group consisting of trifunctional or more (meth)acrylic monomers and trifunctional or more (meth)acrylic oligomers.

[0021] (Advantages of trifunctional or more (meth)acrylic compounds) On the other hand, the electrophotographic photoreceptor according to the present invention contains a trifunctional or more (meth)acrylic compound, which develops a three-dimensional network structure and provides wear resistance suitable for high-speed and long-life applications.

[0022] (Advantages of 1-functional (meth)acrylic compounds 1) On the other hand, the electrophotographic photoreceptor according to the present invention contains a monofunctional (meth)acrylic compound, which allows the monofunctional (meth)acrylic compound to move freely within the composition during the polymerization process and efficiently react with unreacted acryloyloxy groups of other (meth)acrylic compounds, thereby reducing the number of unreacted acryloyloxy groups in the overall composition. As a result, the polymerization rate of the composition increases, contributing to improved wear resistance, similar to the development of the three-dimensional network structure described above. In contrast, in the case of a bifunctional or more (meth)acrylic compound, once one acryloyloxy group reacts, the (meth)acrylic compound becomes fixed at its crosslinking point and cannot move freely within the composition. As a result, the probability of this unreacted acryloyloxy group of the (meth)acrylic compound reacting with unreacted acryloyloxy groups of other (meth)acrylic compounds decreases, and the number of unreacted acryloyloxy groups in the overall composition increases.

[0023] As described above, the surface layer obtained by polymerizing a composition containing a trifunctional or higher (meth)acrylic compound and a monofunctional (meth)acrylic compound exhibits excellent abrasion resistance and possesses sufficient physical strength to withstand high-speed, long-life use. However, repeated use of the photoreceptor leads to a separate problem: an increase in driving torque due to the deterioration of the discharge of the surface layer.

[0024] (Advantages of monofunctional (meth)acrylic compounds 2) The inventors surmise that the increase in driving torque due to repeated use occurs for the following two reasons: (Reason 1) Unreacted acryloyloxy groups exposed on the surface of the photoreceptor are decomposed by discharge, creating highly polar areas on the surface. As a result, the surface layer adsorbs moisture from the atmosphere, increasing the adhesion between the photoreceptor and other components that the photoreceptor contacts during the electrophotographic process, thus increasing the driving torque. (Reason 2) As described in Japanese Patent Application Publication No. 2005-266277, discharge products that adhere to and accumulate on the surface layer of the photoreceptor due to repeated discharge adsorb moisture from the atmosphere, increasing the adhesion between the photoreceptor and other components that the photoreceptor contacts during the electrophotographic process, thus increasing the driving torque.

[0025] As mentioned above, using a monofunctional (meth)acrylic compound reduces the number of unreacted acryloyloxy groups in the overall composition, and this includes unreacted acryloyloxy groups exposed on the surface. Therefore, using a monofunctional (meth)acrylic compound suppresses the increase in driving torque due to (reason 1).

[0026] (Advantages of monofunctional (meth)acrylic compounds 3) When a monofunctional (meth)acrylic compound is used, the crosslinking density of the polymerized acrylic resin decreases, which increases the amount of surface layer abrasion due to friction with the photoreceptor during the electrophotographic process. As a result, a very small amount of discharge products attached to the surface layer are scraped off and removed from the surface layer. This effect suppresses the increase in driving torque caused by the above (reason 2).

[0027] (Advantages of monofunctional (meth)acrylic compounds 4) As described above, the surface layer of the acrylic resin polymerized from a composition containing a monofunctional (meth)acrylic compound is abraded by friction. As a result, abrasive particles containing ester bonds generated by the polymerization reaction are gradually produced with repeated use. These abrasive particles function as a lubricant in the electrophotographic process, and the increase in abrasive particles, especially in the later stages of durability, suppresses the increase in driving torque caused by discharge degradation and the adhesion of discharge products, which promote moisture absorption of the surface layer.

[0028] As described above, the surface layer obtained by polymerizing a composition containing a monofunctional (meth)acrylic compound and a trifunctional or more (meth)acrylic compound exhibits excellent wear resistance at high speeds and with long lifespan, and also suppresses the increase in driving torque due to repeated use. However, in recent years, with the increasing demand for high speeds and long lifespans, the <photoreceptor design> described above alone has been insufficient to stably suppress the increase in driving torque due to repeated use, regardless of various temperature and humidity environments from low temperature and low humidity to high temperature and high humidity, and regardless of various potential settings such as the charging part and the transfer part.

[0029] <Toner Design> The toner according to the present invention must contain hydrotalcite particles containing fluorine as an external additive.

[0030] (Advantage of hydrotalcite particles 1) Hydrotalcite particles, which are layered compounds with strong positive charge properties, incorporate anion discharge products such as NOx between layers through ion exchange. Therefore, the hydrotalcite particles supplied from the developing material to the photoreceptor surface during repeated use continuously incorporate discharge products and carry them away from the photoreceptor surface. As a result, the increase in driving torque due to (reason 2) described above is suppressed.

[0031] (Advantages of hydrotalcite particles 2) Hydrotalcite particles, which are layered compounds, act as a lubricant in the electrophotographic process. When pressure is applied between the photoreceptor and other components it comes into contact with, they cause slippage between the layers, thus suppressing an increase in driving torque.

[0032] (Advantage 1 of hydrotalcite particles containing fluorine) When the hydrotalcite particles described above contain fluorine, the high hydrophobicity provided by the fluorine suppresses moisture adsorption by the hydrotalcite particles from the atmosphere during repeated use. In addition, the fluorine contained in the particles migrates to the surface of the photoreceptor, suppressing moisture absorption on the photoreceptor surface. Due to this effect, the surface layer containing fluorine-containing hydrotalcite particles can suppress the increase in driving torque caused by moisture adhesion.

[0033] (Advantage 2 of hydrotalcite particles containing fluorine) Fluorine, with its high lubricating properties, acts as a lubricant itself, suppressing the increase in driving torque.

[0034] As described above, external additives containing hydrotalcite particles with fluorine suppress the increase in driving torque due to repeated use. However, in recent years, with the increasing demand for high speed and long lifespan, the toner design described above is insufficient to stably suppress the increase in driving torque due to repeated use, regardless of various temperature and humidity environments ranging from low temperature and low humidity to high temperature and high humidity, and regardless of various potential settings such as the charging and transfer parts.

[0035] <Design of a process cartridge combining a photoconductor and toner> The inventors optimized the combination of a photoreceptor and toner, combining a photoreceptor having a surface layer obtained by polymerizing a composition containing a monofunctional (meth)acrylic compound and a trifunctional or more (meth)acrylic compound with a toner containing hydrotalcite particles containing fluorine as an external additive. The inventors found that when this photoreceptor and toner are combined, not only do the effects of suppressing the increase in driving torque described in the above sections on <Photoreceptor Design> and <Toner Design> work additively, but the synergistic effects described below are also obtained.

[0036] In the following explanation of the effects, "fluorine" as a lubricant refers to fluorine-rich fine particles generated when fluorine-containing hydrotalcite particles are crushed, or to fluorine-containing treatment agents that were contained in fluorine-containing hydrotalcite.

[0037] (Advantages of having three lubricants: surface layer debris, hydrotalcite particles, and fluorine) In the latter half of its lifespan, the process cartridge of the present invention experiences increased discharge degradation and adhesion of discharge products, leading to increased moisture absorption and a rise in the driving torque of the photoreceptor. This process cartridge generates nonpolar abrasive particles from the abrasion of the photoreceptor's surface layer, along with hydrotalcite particles with strong positive charge properties and fluorine with strong negative charge properties. The presence of these three lubricants with different charge properties allows for stable suppression of the increase in driving torque due to repeated use, regardless of various temperature and humidity environments ranging from low temperature and low humidity to high temperature and high humidity, or various potential settings such as those in the charging and transfer sections. The inventors speculate on the reason for this as follows.

[0038] The electrophotographic process requires electrostatically transferring charged toner to the photoreceptor during development, and conversely, electrostatically separating the charged toner from the photoreceptor during transfer. Consequently, multiple types of electric fields with varying strengths and directions are inevitably applied to the photoreceptor.

[0039] For example, when reversing the development of negatively charged toner, a large negative charging voltage, a smaller negative development voltage, and a positive transfer voltage of the opposite polarity are applied to the photoreceptor. As another example, when developing positively charged toner in the normal manner, a negative charging voltage, a positive development voltage, and a negative transfer voltage larger than the charging voltage are applied to the photoreceptor.

[0040] As described above, in electrophotographic processes where multiple types of electric fields with varying strengths and directions are applied, repeated use requires the presence of three lubricants with different charge properties: nonpolar, positively charged, and negatively charged. Only then can a stable increase in driving torque be suppressed. For example, in a process where a positive electric field is applied from outside the photoreceptor toward the photoreceptor, positively charged hydrotalcite particles are located on the side farther from the photoreceptor, negatively charged fluorine is located closer to the photoreceptor, and nonpolar abrasive particles are located somewhere in between. As a result, one of the three types of lubricants fills every nook and cranny between the photoreceptor and other components it contacts, achieving stable suppression of driving torque. In processes where a negative electric field is applied from outside the photoreceptor toward the photoreceptor, the distribution of the three types of lubricants is reversed. In contrast, if three lubricants with different charge properties are not present, the lubricant will become localized by the applied electric field in the electrophotographic process, and stable suppression of driving torque cannot be achieved.

[0041] Furthermore, in a mixture of three lubricants with different charge properties, the nonpolar shavings weaken the electrical bonding between the positively charged hydrotalcite particles and the negatively charged fluorine, thus creating a more uniform mixture. In this way, the presence of the nonpolar shavings helps to uniformly loosen the three lubricants, making it easier for them to reconfigure to an optimal state in response to various temperature and humidity changes from low temperature and low humidity to high temperature and high humidity, as well as changes in print density and image density of printed images.

[0042] (Behavior of three types of lubricants in relation to print density and image density of printed images during repeated use) As explained above, in order to achieve stable suppression of drive torque during repeated use, the amount and distribution of the three types of lubricants must always be in an appropriate balance. In this respect, the three types of lubricants of the present invention are automatically optimized for the print density and image density of printed images during repeated use, without the use of a special supply mechanism or detection means. The inventors speculate on the reason for this as follows.

[0043] On the one hand, exposure to the photoreceptor is necessary for the toner containing hydrotalcite particles according to the present invention to be supplied onto the photoreceptor as an external additive. On the other hand, when the photoreceptor is exposed, the amount of electrostatic discharge in that area in the next process increases, and as a result, the amount of abrasion of the surface layer of the present invention increases, and the amount of abrasive powder containing ester bonds increases. Therefore, in response to the amount of exposure which increases or decreases according to the print density and image density, negatively charged fluorine, positively charged hydrotalcite particles, and nonpolar abrasive powder appear on the photoreceptor in conjunction. As a result, the supply balance of these three types of lubricants is automatically optimized.

[0044] Furthermore, when repeated use occurs under conditions of low print density and image density with low exposure, the transfer of fluorine and hydrotalcite particles to the photoreceptor decreases, which in turn suppresses the generation of abrasive particles. As a result, one or two of the three lubricants do not increase excessively, and the amounts of all three lubricants are averaged out. In addition, when exposure is low and the amount of electrostatic discharge is low, discharge degradation and the generation of discharge products themselves are reduced, so the absolute amount required for the three lubricants also decreases. Therefore, the total amount of the three lubricants is linked to discharge degradation and the generation of discharge products, and the total amount of the three lubricants does not increase excessively, so there is no wasteful supply, concerns about filming are reduced, and costs are kept down.

[0045] The process cartridge of the present invention solves the above problems through the above-described design of the photoreceptor, the design of the toner, and the design of the process cartridge combining the photoreceptor and toner. Specifically, firstly, the surface layer obtained by polymerizing a composition containing a monofunctional (meth)acrylic compound and a trifunctional or more (meth)acrylic compound, and the toner containing hydrotalcite particles containing fluorine as an external additive, each additively exert a driving torque suppression effect. Secondly, negatively charged fluorine, positively charged hydrotalcite particles, and abrasive particles containing nonpolar ester bonds synergistically exhibit a stable driving torque suppression effect. In particular, the combination of the photoreceptor surface layer and the toner's external additive of the present invention brings about an effect in which the three types of lubricants are rearranged to an optimal state in response to various changes, and the ratio of the amounts of the three types of lubricants and the absolute value of their total amount are automatically optimized through repeated use due to the means of supplying the three types of lubricants to the photoreceptor.

[0046] As described above, the effects of the present invention can be achieved through the synergistic effects of each component.

[0047] [Electrophotographic photoconductor] The electrophotographic photoreceptor according to the present invention is characterized by having a surface layer. A method for manufacturing an electrophotographic photoreceptor according to the present invention involves preparing coating solutions for each layer, as described later, applying them in the desired layer order, and drying them. Methods for applying the coating solutions include immersion coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, and ring coating. Among these, immersion coating is preferred from the viewpoint of efficiency and productivity. The following explains each layer.

[0048] <Support> In the present invention, the electrophotographic photoreceptor has a support. In the present invention, the support is preferably a conductive support. The shape of the support can be cylindrical, belt-shaped, or sheet-shaped. Among these, a cylindrical support is preferred. Furthermore, the surface of the support may be subjected to electrochemical treatments such as anodizing, blasting, or cutting. Suitable materials for the support include metal, resin, and glass. Examples of metals include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. Among these, aluminum is preferred. In other words, a preferred example of a support is one made of aluminum. Furthermore, conductivity may be imparted to resins and glass by processing such as mixing or coating them with conductive materials.

[0049] <Conductive layer> In the electrophotographic photoreceptor according to the present invention, a conductive layer may be provided on the support. By providing a conductive layer, scratches and irregularities on the surface of the support can be concealed, and the reflection of light on the surface of the support can be controlled. The conductive layer preferably contains conductive particles and a resin.

[0050] Examples of materials for conductive particles include metal oxides, metals, and carbon black. Examples of metal oxides include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, and bismuth oxide. Examples of metals include aluminum, nickel, iron, nichrome, copper, zinc, and silver. Among these, it is preferable to use metal oxides as conductive particles, and it is more preferable to use titanium oxide, tin oxide, or zinc oxide. When using metal oxides as conductive particles, the surface of the metal oxide may be treated with a silane coupling agent or doped with elements such as phosphorus or aluminum, or their oxides. Examples of elements and oxides that can be doped include phosphorus, aluminum, niobium, and tantalum. Furthermore, the conductive particles may have a laminated structure comprising core material particles and a coating layer covering those particles. Examples of core material particles include titanium oxide, barium sulfate, and zinc oxide. Examples of coating layers include metal oxides such as tin oxide and titanium oxide. Furthermore, when using metal oxides as conductive particles, their volume-average particle size is preferably 1 nm to 500 nm, and more preferably 3 nm to 400 nm.

[0051] Examples of resins include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenolic resin, and alkyd resin. Furthermore, the conductive layer may further contain silicone oil, resin particles, a concealing agent such as titanium dioxide, etc.

[0052] The average 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.

[0053] A conductive layer can be formed by preparing a coating solution for a conductive layer containing the above-mentioned materials and solvents, forming a coating film, and drying it. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Methods for dispersing conductive particles in the coating solution for a conductive layer include using a paint shaker, sand mill, ball mill, or liquid impaction type high-speed disperser.

[0054] <Underlayer> In the electrophotographic photoreceptor according to the present invention, an undercoat layer may be provided on the support or conductive layer. By providing an undercoat layer, the interlayer adhesion function is enhanced and a charge injection blocking function can be provided.

[0055] The undercoat layer preferably contains a resin. Alternatively, the undercoat layer may be formed as a cured film by polymerizing a composition containing a monomer having polymerizable functional groups.

[0056] Examples of resins include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenolic resin, polyvinylphenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, polyamide resin, polyamic acid resin, polyimide resin, polyamide-imide resin, and cellulose resin.

[0057] Polymerizable functional groups found in monomers possessing polymerizable functional groups include isocyanate groups, blocked isocyanate groups, methylol groups, alkylated methylol groups, epoxy groups, metal alkoxide groups, hydroxyl groups, amino groups, carboxyl groups, thiol groups, carboxylic acid anhydride groups, and carbon-carbon double bond groups.

[0058] Furthermore, the undercoat layer may further contain electron transport materials, metal oxides, metals, conductive polymers, etc., for the purpose of improving electrical properties. Among these, electron transport materials and metal oxides are preferred. Examples of electron transport materials include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, aryl halides, silole compounds, and boron-containing compounds. An electron transport material having polymerizable functional groups may be used as the electron transport material, and a base layer may be formed as a cured film by copolymerizing it with the above-mentioned monomers having polymerizable functional groups. Examples of metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, and silicon dioxide. Examples of metals include gold, silver, and aluminum. Furthermore, the underlayer may contain additional additives.

[0059] The average 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.

[0060] The undercoat can be formed by preparing an undercoat coating solution containing the above-mentioned materials and solvents, forming a coating film, and then drying and / or curing it. Examples of solvents used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0061] <Photosensitive layer> The photosensitive layers of the electrophotographic photoreceptor according to the present invention are mainly classified into (1) a stacked photosensitive layer and (2) a single-layer photosensitive layer. (1) The stacked photosensitive layer has a charge generating layer containing a charge generating material and a charge transport layer containing a charge transport material. (2) The single-layer photosensitive layer has a photosensitive layer containing both a charge generating material and a charge transport material.

[0062] (1) Stacked photosensitive layer The stacked photosensitive layer comprises a charge generation layer and a charge transport layer.

[0063] (1-1) Charge generation layer The charge generation layer preferably contains a charge generation material and a resin.

[0064] Examples of charge-generating materials include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, and phthalocyanine pigments. Among these, azo pigments and phthalocyanine pigments are preferred. Among phthalocyanine pigments, oxytitanium phthalocyanine pigments, chlorogallium phthalocyanine pigments, and hydroxygallium phthalocyanine pigments are preferred. The content of the charge generating material in the charge generating layer is preferably 40% to 85% by mass, and more preferably 60% to 80% by mass, relative to the total mass of the charge generating layer.

[0065] Examples of resins include polyester resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl butyral resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenolic resin, polyvinyl alcohol resin, cellulose resin, polystyrene resin, polyvinyl acetate resin, and polyvinyl chloride resin. Among these, polyvinyl butyral resin is more preferred.

[0066] Furthermore, the charge generation layer may contain additives such as antioxidants and ultraviolet absorbers. Specifically, examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.

[0067] The average thickness of the charge generation layer is preferably 0.1 μm or more and 1 μm or less, and more preferably 0.15 μm or more and 0.4 μm or less.

[0068] The charge generation layer can be formed by preparing a coating solution for the charge generation layer containing the above-mentioned materials and solvents, forming a coating film, and drying it. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0069] (1-2) Charge transport layer The charge transport layer preferably contains a charge transport material and a resin.

[0070] Examples of charge transport materials include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. Among these, triarylamine compounds and benzidine compounds are preferred. The content of the charge transport material in the charge transport layer is preferably 25% by mass or more and 70% by mass or less, and more preferably 30% by mass or more and 55% by mass or less, based on the total mass of the charge transport layer.

[0071] Examples of resins include polyester resin, polycarbonate resin, acrylic resin, and polystyrene resin. Among these, polycarbonate resin, polyester resin, and acrylic resin are preferred. Polyarylate resin is particularly preferred among polyester resins. The content ratio (mass ratio) of the charge transport material to the resin is preferably 4:10 to 20:10, and more preferably 5:10 to 12:10.

[0072] Furthermore, the charge transport layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, lubrication agents, and wear resistance enhancers. Specifically, examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0073] The average thickness of the charge transport layer is preferably 5 μm to 50 μm, more preferably 8 μm to 40 μm, and particularly preferably 10 μm to 30 μm.

[0074] The charge transport layer can be formed by preparing a coating solution for the charge transport layer containing the above-mentioned materials and solvents, forming a coating film, and drying it. Examples of solvents used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Among these solvents, ether-based solvents or aromatic hydrocarbon-based solvents are preferred.

[0075] (2) Single-layer photosensitive layer A single-layer photosensitive layer can be formed by preparing a coating solution for a photosensitive layer containing a charge generating substance, a charge transporting substance, a resin, and a solvent, forming this coating film, and drying it. The charge generating substance, charge transporting substance, and resin are the same as the examples of materials in "(1) Multilayer Photosensitive Layer" above.

[0076] <Protective layer> In the electrophotographic photoreceptor according to the present invention, a protective layer may be provided on the photosensitive layer. Providing a protective layer can improve durability.

[0077] The protective layer, intended to provide durability for a long lifespan, can be any high-strength layer containing resin, for example; it is not necessarily required to include conductive particles or charge transport materials to enhance charge transport performance. However, from the viewpoint of improving the fundamental electrical properties of the electrophotographic photoreceptor, it is preferable to include conductive particles and / or charge transport materials along with resin to achieve both durability and fundamental electrical properties.

[0078] Examples of conductive particles include metal oxide particles such as titanium oxide, zinc oxide, tin oxide, and indium oxide.

[0079] Examples of charge transport materials include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. Among these, triarylamine compounds and benzidine compounds are preferred.

[0080] Examples of resins include polyester resin, acrylic resin, phenoxy resin, polycarbonate resin, polystyrene resin, phenolic resin, melamine resin, and epoxy resin. Among these, polycarbonate resin, polyester resin, and acrylic resin are preferred.

[0081] Furthermore, the protective layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of reactions in this process include thermal polymerization, photopolymerization, and radiation polymerization. Examples of polymerizable functional groups in monomers having a polymerizable functional group include acryloyl groups and methacryloyl groups. Materials with charge transport ability may be used as monomers having a polymerizable functional group.

[0082] The protective layer may contain additives such as antioxidants, UV absorbers, plasticizers, leveling agents, lubrication agents, and wear resistance enhancers. Specifically, examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0083] The average thickness of the protective layer is preferably 0.5 μm to 10 μm, and more preferably 1 μm to 7 μm.

[0084] The protective layer can be formed by preparing a protective coating solution containing the above-mentioned materials and solvents, forming a coating film, and then drying and / or curing it. Examples of solvents used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, sulfoxide-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0085] <Surface layer> In the electrophotographic photoreceptor according to the present invention, the surface layer must be a polymerized film of a composition containing at least one monofunctional (meth)acrylic compound selected from the group consisting of monofunctional (meth)acrylic monomers and monofunctional (meth)acrylic oligomers, and at least one trifunctional or more (meth)acrylic compound selected from the group consisting of trifunctional or more (meth)acrylic monomers and trifunctional or more (meth)acrylic oligomers.

[0086] The surface layer, as referred to here, is the portion of the electrophotographic photoreceptor that comes into contact with toner and various other components during the electrophotographic process. While a protective layer, charge transport layer, single-layer photosensitive layer, and charge generation layer can all serve as the surface layer, from the viewpoint of balancing durability with the fundamental electrical characteristics in the electrophotographic process, the surface layer is preferably a protective layer or a charge transport layer, and more preferably a protective layer.

[0087] When the content ratio of a monofunctional (meth)acrylic monomer compound relative to a trifunctional (meth)acrylic monomer compound is denoted as a[mass%], a[mass%] is preferably 20 to 500 mass%. On the one hand, if a is less than 20 mass%, the advantages described in (Advantage 1 of monofunctional (meth)acrylic compounds), (Advantage 2 of monofunctional (meth)acrylic compounds), (Advantage 3 of monofunctional (meth)acrylic compounds), and (Advantage 4 of monofunctional (meth)acrylic compounds) above will be weakened. Also, the effects described in (Advantages of having three lubricants: surface layer chips, hydrotalcite particles, and fluorine) and (Behavior of the three lubricants on the print density and image density of printed images during repeated use) above will be weakened. In particular, the supply of chips containing nonpolar ester bonds will decrease, and the balance of the three lubricants with different electrostatic properties will deteriorate. On the other hand, if a is greater than 500 mass%, the advantages described in (Advantages of trifunctional or more (meth)acrylic compounds) above will be weakened. Furthermore, the effects described above (the advantages of having three lubricants: surface layer debris, hydrotalcite particles, and fluorine) and (the behavior of the three lubricants on the print density and image density of printed images during repeated use) are weakened. In particular, the supply of debris containing nonpolar ester bonds increases, worsening the balance of the three lubricants with different electrostatic properties.

[0088] The elastic deformation rate of the surface layer is preferably 35-50% from the viewpoint of optimizing the supply of nonpolar ester bond-containing chips during repeated use. On the one hand, if the elastic deformation rate is less than 35%, the surface layer becomes more easily worn, increasing the supply of nonpolar ester bond-containing chips and worsening the balance of the three lubricants with different electrostatic properties. On the other hand, if the elastic deformation rate is greater than 50%, the surface layer does not wear down, decreasing the supply of nonpolar ester bond-containing chips and worsening the balance of the three lubricants with different electrostatic properties.

[0089] From the viewpoint of achieving both durability and basic electrical properties, monofunctional (meth)acrylic monomer compounds are preferably equipped with charge transport sites.

[0090] Examples of charge transport sites include hole-transporting structures such as triarylamines, hydrazones, pyrazolines, and carbazoles, as well as electron-transporting structures such as condensed polycyclic quinones, diphenoquinones, and electron-withdrawing aromatic rings having cyano or nitro groups. Among these, triarylamine structures are preferred from the viewpoint of improving charge transport capability in order to enhance the basic electrical properties of the electrophotographic photoreceptor.

[0091] However, monofunctional (meth)acrylic monomers having a triarylamine structure may aggregate due to the high stackability of the triarylamine structures. When extreme aggregation occurs, not only is the charge transport capacity of the triarylamine structure not fully exhibited, resulting in a deterioration of the basic electrical properties, but the advantages described in (Advantage 1 of monofunctional (meth)acrylic compounds) and (Advantage 2 of monofunctional (meth)acrylic compounds) above are weakened. In particular, the effect of the monofunctional (meth)acrylic compound in reducing unreacted acryloyloxy groups exposed on the surface of the electrophotographic photoreceptor is weakened, so the unreacted acryloyloxy groups are decomposed by discharge, creating highly polar areas on the surface, making it easier for the surface layer to adsorb moisture from the atmosphere. As a result, the adhesion between the electrophotographic photoreceptor and other components that the electrophotographic photoreceptor comes into contact with during the electrophotographic process increases, making it easier for the driving torque to increase.

[0092] In order to address the tendency of the triarylamine structure to aggregate as described above, and from the viewpoint of improving the dispersibility of monofunctional (meth)acrylic compounds having a triarylamine structure, it is preferable that the monofunctional (meth)acrylic compound is a compound represented by the following formula (A1) or (A2). [ka] (In formula (A1), R 101 ~R 119 Each of these independently represents a hydrogen atom, a methyl group, or an ethyl group. m and n are each independently integers between 0 and 5. [ka] (In formula (A2), R 201 ~R 219 Each of these independently represents a hydrogen atom, a methyl group, or an ethyl group. p and q are each independently integers between 0 and 5.

[0093] The monofunctional (meth)acrylic compounds represented by the above formulas (A1) or (A2) suppress aggregation caused by the high stackability of triarylamine structures by distorting the molecular structure through the phenylene group, which is bonded to the triarylamine moiety via an alkylene group having 0 to 5 carbon atoms.

[0094] On the other hand, stacking triarylamine structures can sometimes improve charge transport capacity. From the viewpoint of optimizing charge transport capacity by appropriately stacking while suppressing aggregation and improving electrical properties, it is preferable that m in formula (A1) is 2 or less, and more preferably 0. It is preferable that p in formula (A2) is 2 or less, and more preferably 0. Also, it is preferable that n in formula (A1) is 3 or less, and more preferably 2. It is preferable that q in formula (A2) is 3 or less, and more preferably 2.

[0095] Among these, the compound represented by formula (A1) is preferred from the viewpoint of ease of polymerization and high charge transport properties after polymerization, R 119 It is more preferable that it be hydrogen.

[0096] The surface layer contains a diphenylamine compound represented by the following formula (A3), and it is preferable that the content of the diphenylamine compound is 0.001% by mass or more and 1.0% by mass or less relative to the total mass of the surface layer. [ka] (In formula (A3), R 301 ~R 310 Each of these independently represents a hydrogen atom, a methyl group, or an ethyl group.

[0097] The diphenylamine compound represented by formula (A3) above functions as a chain-transfer type polymerization inhibitor (Reference: Takayuki Otsu, On the Function of Polymerization Inhibitors, Organic Synthesis Chemistry, Vol. 33, No. 8 (1975), pp. 634-640). When this compound is included within the above range, it becomes easier to optimize the degree of polymerization of the surface layer. Therefore, while ensuring wear resistance suitable for high speed and long life as a prerequisite, the supply of chips containing nonpolar ester bonds becomes appropriate, making it easier to balance the three lubricants with different electrostatic properties. If the content ratio of the diphenylamine compound represented by formula (A3) above to the surface layer is less than 0.001% by mass, the above function as a polymerization inhibitor cannot be obtained. Conversely, if the content ratio is greater than 1.0% by mass, polymerization is suppressed, making it easier for the wear resistance of the surface layer to decrease, and / or, the supply of chips increases, making it easier for the balance of the three lubricants with different electrostatic properties to deteriorate.

[0098] The surface layer preferably contains particles A, which include metal atoms. The presence of metal atoms in the surface layer makes it easier to balance the wear resistance of the surface layer with the supply of abrasive particles. In addition, the reducing properties of the metal atoms negatively affect the discharge products generated during repeated use, and the positively charged hydrotalcite particles can more easily take in the discharge products through ion exchange, thereby enhancing the effect described in (Advantage 1 of hydrotalcite particles) above.

[0099] Furthermore, from the viewpoint of reducing properties, dispersibility, and electrical resistance, particle A is more preferably a metal oxide particle, and even more preferably alumina particle. From the same viewpoint, the content ratio of particle A in the surface layer is preferably 4% by mass or more and 16% by mass or less of the total mass of the surface layer.

[0100] The average thickness of the surface layer is preferably 0.5 μm to 5 μm if the surface layer does not contain conductive particles or charge transport materials. On the one hand, if it is thinner than 0.5 μm, there is a higher possibility that there will be areas not covered by the surface layer, and the surface layer may not be able to perform its function. On the other hand, if it is thicker than 5 μm, once the electrophotographic photoreceptor is charged during the electrophotographic process, the surface layer will retain a large shared voltage due to the lack of charge transport function, resulting in an extremely large residual potential and deterioration of the basic electrical properties. If the surface layer contains conductive particles or charge transport materials, the average thickness is preferably 0.5 μm to 10 μm, and preferably 1 μm to 7 μm.

[0101] The surface layer can be formed by preparing a coating solution for the surface layer containing at least one monofunctional (meth)acrylic compound selected from the group consisting of monofunctional (meth)acrylic monomers and monofunctional (meth)acrylic oligomers, at least one trifunctional or more (meth)acrylic compound selected from the group consisting of trifunctional or more (meth)acrylic monomers and trifunctional or more (meth)acrylic oligomers, the materials described above in <photosensitive layer> and / or <protective layer>, and a solvent, forming this coating film, and drying and / or curing it. Examples of solvents used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, sulfoxide-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0102] The surface layer is formed as a cured film by polymerizing a composition containing the above-mentioned monofunctional (meth)acrylic compound and a trifunctional or more (meth)acrylic compound. Examples of reactions used in this process include thermal polymerization, photopolymerization, and radiation polymerization.

[0103] From the viewpoint of adopting a simple polymerization method, it is more preferable that the content ratio of the diphenylamine compound represented by the above formula (A3) to the surface layer is 0.1% by mass or less relative to the total mass of the surface layer. By setting it to 0.1% by mass or less, when applying external energy to advance the polymerization reaction and cure, it becomes easier to cure using heat, light, or ultraviolet light, which are easier to simplify the apparatus, instead of using strong radiation such as electron beams as the external energy source, which tend to make the apparatus complex.

[0104] <Method for identifying monofunctional (meth)acrylic compounds and trifunctional or multifunctional (meth)acrylic compounds> The electrophotographic photoreceptor of the present invention has a surface layer formed by polymerizing a composition containing at least one monofunctional (meth)acrylic compound selected from the group consisting of monofunctional (meth)acrylic monomers and monofunctional (meth)acrylic oligomers, and at least one trifunctional or more (meth)acrylic compound selected from the group consisting of trifunctional or more (meth)acrylic monomers and trifunctional or more (meth)acrylic oligomers. The structural formulas of these multiple types of acrylic monomers and / or acrylic oligomers, and their content ratios, can be identified as follows.

[0105] (1) Immerse the electrophotographic photoreceptor in chloroform. Since the surface layer formed by polymerizing the acrylic compound is insoluble in chloroform, the surface layer separates from the electrophotographic photoreceptor in chloroform, and a chloroform solution is obtained in which the layer below the surface layer has dissolved. (2) The above-mentioned solution is analyzed using chromatography, precision mass spectrometry, nuclear magnetic resonance spectroscopy, pyrolysis gas chromatography, etc., to identify the components from which multiple types of unreacted acrylic monomers and / or acrylic oligomers contained in the layer below the surface layer have been separated. (3) Prepare a certain amount of the identified multiple types of acrylic monomers and / or acrylic oligomers by synthesizing or purchasing them, and polymerize them individually. (4) The multiple polymers obtained above are each analyzed by infrared absorption spectroscopy, and a calibration peak is determined from the obtained infrared absorption spectrum to be used to obtain a calibration curve. At that time, the calibration peak of each acrylic monomer is selected so as to maximize the peak intensity, under the condition that the calibration peaks of other polymers do not fall within a range of three times the full width at half maximum of the calibration peak. (5) For each polymer, a calibration range is determined that is defined as a range of three times the full width at half maximum, centered on the calibration peak. (6) When at least two types of unreacted acrylic monomers and / or acrylic oligomers are polymerized by mixing them in at least two mixing ratios, the infrared absorption spectra are measured, and the integral values ​​of the above calibration ranges are compared to obtain a calibration curve for each acrylic monomer and / or acrylic oligomer. (7) The surface layer of the photoreceptor to be identified is analyzed by infrared absorption spectroscopy, and the mixing ratio of each acrylic monomer and / or acrylic oligomer contained in the surface layer is calculated from the obtained infrared absorption spectrum-1 and the calibration curves of each acrylic monomer and / or acrylic oligomer. (8) The infrared absorption spectrum-2 of the polymer obtained by mixing each acrylic monomer and / or acrylic oligomer in the above mixing ratio is measured. (9) When comparing the infrared absorption spectrum-1 and the infrared absorption spectrum-2, confirm that the integral value of the difference spectrum in the calibration range of each acrylic monomer and / or acrylic oligomer is 10% or less of the integral value in the calibration range of the infrared absorption spectrum-2.

[0106] Furthermore, steps (1) and (2) in the above identification method can be replaced by component identification using other methods, including literature review. In addition, if it can be confirmed in step (9) that the surface layer of the target is indeed polymerized from multiple types of acrylic monomers and / or acrylic oligomers that are candidates for identification, then steps (3) through (8), in addition to (1) and (2), can also be replaced by other methods.

[0107] <Measurement of elastic deformation rate> The elastic deformation rate of the surface layer of the electrophotographic photoreceptor of the present invention was measured as follows. Measuring instrument used: Fischer hardness tester (product name: H100VP-HCU, manufactured by Fischer) Measurement environment: temperature 23℃ humidity 50%RH Indenter: Vickers square pyramidal diamond indenter with a 136° face angle. Under the above conditions, an indenter was pressed into the surface layer, and a load of 2 mN was applied over 7 seconds. Then, the indentation depth was continuously measured while gradually decreasing the load over 7 seconds until it reached 0 mN. The elastic deformation rate was determined from these results.

[0108] <Method for identifying diphenylamine compounds> The presence of a diphenylamine compound represented by the following formula (A3) in the surface layer of the electrophotographic photoreceptor of the present invention, and the proportion of this compound in the surface layer, can be identified as follows. (1) The surface layer of the electrophotographic photoreceptor is scraped off and immersed in chloroform to obtain a chloroform solution from which the diphenylamine compound has dissolved. (2) The above solution is analyzed using chromatography and high-precision mass spectrometry to separate the diphenylamine compound and identify its structural formula and content.

[0109] <Method for identifying particle A containing metal atoms> The surface layer of the electrophotographic photoreceptor according to the present invention contains particles A containing metal atoms, and the composition of these particles A and their proportion in the surface layer can be identified as follows.

[0110] (Identification of composition) (1) Cut a cross-section of the surface layer of the photoreceptor and observe it with a scanning electron microscope. (2) Particle A present in the observation area is subjected to energy-dispersive X-ray analysis to identify its composition.

[0111] (Identification of content ratio) (1) Immerse the photoreceptor in chloroform. Since the surface layer formed by polymerizing the acrylic compound is insoluble in chloroform, the surface layer is separated from the photoreceptor in chloroform. (2) The separated surface layers are washed and dried, and then subjected to thermogravimetric analysis. (3) The content ratio is identified by comparing the weight at low temperatures with the weight after all organic matter has been burned at high temperatures.

[0112] [toner] The toner according to the present invention is characterized by comprising toner particles and an external additive. The following describes the individual components that make up the toner and the manufacturing method of the toner.

[0113] <Toner manufacturing method> This section describes the manufacturing method for toner particles. The toner particles can be manufactured using known methods, including kneading and grinding methods and wet manufacturing methods. From the viewpoint of uniform particle size and shape control, wet manufacturing methods are preferably used. Furthermore, examples of wet manufacturing methods include suspension polymerization, dissolution and suspension, emulsion polymerization and agglutination, and emulsion and agglutination, with emulsion and agglutination being preferably used.

[0114] In the emulsification and coagulation method, first, materials such as fine particles of binder resin and fine particles of colorant are dispersed and mixed in an aqueous medium containing a dispersion stabilizer. A surfactant may also be added to the aqueous medium. Then, a coagulant is added to coagulate the materials until they reach the desired toner particle size, and then, or simultaneously with coagulation, the resin particles are fused together. Furthermore, if necessary, the shape is controlled by heat to form the toner particles.

[0115] Here, the binder resin fine particles can also be composite particles formed from multiple layers, each consisting of two or more layers of resins with different compositions. For example, they can be manufactured by emulsion polymerization, miniemulsion polymerization, phase inversion emulsification, or by combining several manufacturing methods.

[0116] When toner particles contain internal additives such as colorants, the internal additives may be incorporated into the resin microparticles, or a dispersion of internal additive microparticles consisting solely of the internal additive may be prepared separately, and these internal additive microparticles may be agglomerated together with the resin microparticles when agglomerating them.

[0117] Furthermore, by adding resin microparticles with different compositions at different time intervals during aggregation, it is possible to create toner particles with layered structures of different compositions.

[0118] The following can be used as dispersion stabilizers: Examples of inorganic dispersion stabilizers include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, and alumina. Examples of organic dispersion stabilizers include polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salts of carboxymethylcellulose, and starch.

[0119] Known cationic surfactants, anionic surfactants, and nonionic surfactants can be used as surfactants. Specific examples of cationic surfactants include dodecylammonium bromide, dodecyltrimethylammonium bromide, dodecylpyridinium chloride, dodecylpyridinium bromide, and hexadecyltrimethylammonium bromide. Specific examples of nonionic surfactants include dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, nonylphenyl polyoxyethylene ether, lauryl polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, styrylphenyl polyoxyethylene ether, and monodecanoyl sucrose. Specific examples of anionic surfactants include aliphatic soaps such as sodium stearate and sodium laurate, as well as sodium lauryl sulfate, sodium dodecylbenzenesulfonate, and sodium polyoxyethylene(2) lauryl ether sulfate.

[0120] <Binding resin> This section describes the binder resin that makes up the toner particles. Suitable examples of binder resins include vinyl resins and polyester resins.

[0121] Examples of vinyl resins, polyester resins, and other binder resins include the following resins or polymers: Monopolymers of styrene and its substituted products such as polystyrene and polyvinyltoluene; styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers, styrene-methyl acrylate copolymers, styrene-ethyl acrylate copolymers, styrene-butyl acrylate copolymers, styrene-octyl acrylate copolymers, styrene-dimethylaminoethyl acrylate copolymers, styrene-methyl methacrylate copolymers, styrene-ethyl methacrylate copolymers, styrene-butyl methacrylate copolymers, styrene-dimethylaminoethyl methacrylate copolymers, styrene-vinyl methyl ether copolymers, styrene-vinyl ethyl ether copolymers, styrene-vinyl methyl ketone copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-maleic acid copolymers, styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resins, polyamide resins, epoxy resins, polyacrylic resins, rosin, modified rosin, terpene resins, phenolic resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins. These binder resins can be used individually or in combination.

[0122] The binder resin preferably contains a carboxyl group, and is preferably a resin produced using a polymerizable monomer containing a carboxyl group. Examples include vinyl carboxylic acids such as acrylic acid, methacrylic acid, α-ethylacrylic acid, and crotonic acid; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, and itaconic acid; and unsaturated dicarboxylic acid monoester derivatives such as monoacryloyloxyethyl succinate, monomethacryloyloxyethyl succinate, monoacryloyloxyethyl phthalate, and monomethacryloyloxyethyl phthalate.

[0123] As the polyester resin, the following condensation polymers of carboxylic acid components and alcohol components can be used. Examples of carboxylic acid components include terephthalic acid, isophthalic acid, phthalic acid, fumaric acid, maleic acid, cyclohexanedicarboxylic acid, and trimellitic acid. Examples of alcohol components include bisphenol A, hydrogenated bisphenol, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, glycerin, trimethylolpropane, and pentaerythritol.

[0124] Furthermore, the polyester resin may be a polyester resin containing urea groups. It is preferable that the carboxyl groups at the ends of the polyester resin are not capped.

[0125] <Crosslinking agent> To control the molecular weight of the binder resin that constitutes the toner particles, a crosslinking agent may be added during the polymerization of polymerizable monomers.

[0126] For example, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, divinylbenzene, bis(4-acryloxypolyethoxyphenyl)propane, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol #200, #400, and #600 diacrylates, dipropylene glycol diacrylate, polypropylene glycol diacrylate, polyester-type diacrylate (MANDA Nippon Kayaku), and those in which the above acrylates are replaced with methacrylates.

[0127] The amount of crosslinking agent added is preferably 0.001 parts by mass or more and 15.000 parts by mass or less per 100 parts by mass of polymerizable monomer.

[0128] <Release agent> It is preferable to include a mold release agent as one of the materials constituting the toner particles. In particular, using an ester wax having a melting point of 60°C to 90°C is preferable because it has excellent compatibility with the binder resin, making it easier to obtain a plasticizing effect.

[0129] Examples of ester waxes include waxes mainly composed of fatty acid esters such as carnauba wax and montanate ester wax; and fatty acid esters from which some or all of the acid component has been deacidified, such as deacidified carnauba wax; methyl ester compounds having a hydroxyl group obtained by hydrogenation of vegetable oils and fats; saturated fatty acid monoesters such as stearyl stearate and behenyl behenate; diesterified products of saturated aliphatic dicarboxylic acids and saturated aliphatic alcohols such as dibehenyl sebacate, distearyl dodecanediol, and distearyl octadecanediol; and diesterified products of saturated aliphatic diols and saturated aliphatic monocarboxylic acids such as nonanediol dibehenate and dodecanediol distearate.

[0130] Furthermore, among these waxes, it is preferable that they contain a bifunctional ester wax (diester) having two ester bonds in its molecular structure.

[0131] Bifunctional ester waxes are ester compounds of a dihydric alcohol and an aliphatic monocarboxylic acid, or ester compounds of a dihydric carboxylic acid and an aliphatic monoalcohol.

[0132] Specific examples of the above-mentioned aliphatic monocarboxylic acids include myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melissic acid, oleic acid, vaccenic acid, linoleic acid, and linolenic acid.

[0133] Specific examples of the above-mentioned aliphatic monoalcohols include myristyl alcohol, cetanol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, tetracosanol, hexacosanol, octacosanol, and triacontanol.

[0134] Specific examples of divalent carboxylic acids include butanediic acid (succinic acid), pentanediic acid (glutaric acid), hexanediic acid (adipic acid), heptanediic acid (pimelic acid), octanedioic acid (suberic acid), nonanedioic acid (azelaic acid), decanediic acid (sebacic acid), dodecanediic acid, tridecanediic acid, tetradecanediic acid, hexadecanedioic acid, octadecanediic acid, eicosanedioic acid, phthalic acid, isophthalic acid, and terephthalic acid.

[0135] Specific examples of dihydric alcohols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, 1,20-eicosanediol, 1,30-triacontanediol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, spiroglycol, 1,4-phenylene glycol, bisphenol A, and hydrogenated bisphenol A.

[0136] Other usable release agents include paraffin wax, microcrystalline wax, petroleum-based waxes such as petrolatum and their derivatives, montan wax and its derivatives, hydrocarbon waxes and their derivatives produced by the Fischer-Tropsch process, polyolefin waxes such as polyethylene and polypropylene and their derivatives, natural waxes such as carnauba wax and candelilla wax and their derivatives, higher aliphatic alcohols, fatty acids such as stearic acid and palmitic acid, or compounds thereof.

[0137] Furthermore, the release agent content is preferably 5.0 parts by mass or more and 20.0 parts by mass or less per 100.0 parts by mass of the binder resin or polymerizable monomer.

[0138] <Coloring agent> When toner particles contain a colorant, there are no particular limitations, and the known ones listed below can be used.

[0139] Yellow pigments used include condensed azo compounds such as yellow iron oxide, Navel Yellow, Naphthol Yellow S, Hansa Yellow G, Hansa Yellow 10G, benzidine Yellow G, benzidine Yellow GR, quinoline yellow lake, permanent yellow NCG, and tartrazine lake, as well as isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specifically, the following can be mentioned. CI Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 155, 168, 180.

[0140] Examples of red pigments include condensed azo compounds such as red iron oxide, permanent red 4R, lysol red, pyrazolone red, watching red calcium salt, lake red C, lake red D, brilliant carmine 6B, brilliant carmine 3B, eosin lake, rhodamine lake B, and alizarin lake, as well as diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specifically, the following can be mentioned. CI Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, 254.

[0141] Examples of blue pigments include alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partial chloride, first sky blue, copper phthalocyanine compounds and their derivatives such as induthlene blue BG, anthraquinone compounds, and basic dye lake compounds. Specifically, the following can be mentioned. CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, 66.

[0142] Examples of black pigments include carbon black and aniline black. These colorants can be used individually, in combination, or even in solid solution form.

[0143] Furthermore, the colorant content is preferably 3.0 parts by mass or more and 15.0 parts by mass or less per 100.0 parts by mass of the binder resin or polymerizable monomer.

[0144] <Charge control agents and charge control resins> The toner particles may contain a charge control agent. Known charge control agents can be used. A charge control agent that has a fast charging speed and can stably maintain a constant charge level is particularly preferred.

[0145] Examples of charge control agents that control the charge properties of toner particles according to the load include the following: Examples of organometallic compounds and chelates include monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, and metal compounds of oxycarboxylic and dicarboxylic acid systems. Other examples include aromatic oxycarboxylic acids, aromatic mono and polycarboxylic acids and their metal salts, anhydrides or esters, and phenol derivatives such as bisphenol. Furthermore, examples include urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, and calixarenes.

[0146] On the other hand, the following are examples of charge control agents that control the positive charge of toner particles: nigrosine modified products; guanidine compounds; imidazole compounds; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate, and onium salts such as phosphonium salts, which are analogs thereof, and their lake pigments; triphenylmethane dyes and their lake pigments (such as phosphotungstic acid, phosphomolybdic acid, phosphotungstenmolybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc. as lake agents); metal salts of higher fatty acids; resin-based charge control agents.

[0147] The charge control agent may be included alone or in combination of two or more types. The charge control agent is preferably contained in an amount of 0.01 parts by mass or more and 10.00 parts by mass or less per 100.00 parts by mass of the binder resin or polymerizable monomer.

[0148] <External additives> The toner according to the present invention contains hydrotalcite particles as an additive, and in filter fitting analysis in STEM-EDS analysis, it is necessary that the hydrotalcite particles contain fluorine.

[0149] Hydrotalcite particles are generally represented by the following structural formula (1). M 2+ y M 3+ x (OH)2A n- (x / n) ·mH2O Formula (1) Here, 0 < x ≤ 0.5, y = 1 - x, and m ≥ 0. The above M 2+ , and M 3+ each represent a divalent and a trivalent metal, respectively.

[0150] M 2+ is preferably at least one divalent metal ion selected from the group consisting of Mg, Zn, Ca, Ba, Ni, Sr, Cu, and Fe. M 3+ is preferably at least one trivalent metal ion selected from the group consisting of Al, B, Ga, Fe, Co, and In.

[0151] ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​It is preferable that the hydrotalcite particles of the present invention contain aluminum. In other words, it is preferable that the hydrotalcite particles of the present invention contain fluorine, magnesium, and aluminum.

[0153] Hydrotalcite particles may be solid solutions containing multiple different elements. They may also contain trace amounts of monovalent metals.

[0154] The number-average particle size of the primary particles of the hydrotalcite particles is preferably 60 nm to 1000 nm, and more preferably 60 nm to 800 nm.

[0155] If the number-average particle size of the primary hydrotalcite particles is greater than 1000, the toner's fluidity tends to decrease, resulting in a decrease in charge resistance during durability.

[0156] The hydrotalcite particles may be hydrophobized using a surface treatment agent, separate from the fluorine treatment. Suitable surface treatment agents include higher fatty acids, coupling agents, esters, and oils such as silicone oil. Among these, higher fatty acids are preferred, with stearic acid, oleic acid, and lauric acid being specific examples.

[0157] When the content ratio of the above hydrotalcite particles to the toner is denoted as b[%], it is preferable that b is 0.010% by mass or more and 3.000% by mass or less. On the one hand, if b is less than 0.010 mass%, the amount of hydrotalcite particles supplied to the photoreceptor surface layer when the toner is developed is small, thus weakening the effects described in (Advantage 1 of hydrotalcite particles) and (Advantage 2 of hydrotalcite particles) above. On the other hand, if b is greater than 3.000 mass%, the supply of hydrotalcite particles to the surface layer increases, worsening the balance of the three lubricants with different charge properties. As a result, the effects described in (Advantages of having three lubricants: surface layer abrasives, hydrotalcite particles, and fluorine) and (Behavior of the three lubricants on the print density and image density of printed images during repeated use) above are weakened. Furthermore, if b is greater than 3.000% by mass, the fluidity of the toner tends to decrease, which can easily lead to problems such as poor developability.

[0158] In filter fitting analysis using STEM-EDS analysis, the hydrotalcite particles contain magnesium and aluminum, and in filter fitting analysis using STEM-EDS analysis, the elemental ratio (ratio of atomic concentrations) of magnesium to aluminum, Mg / Al, is preferably 1.5 to 4.0, and more preferably 1.6 to 3.8.

[0159] In filter fitting analysis using STEM-EDS analysis, it is preferable that the elemental ratio (ratio of atomic concentrations) F / Al of fluorine to aluminum in the hydrotalcite particles is 0.03 to 0.70. On the one hand, if F / Al is less than 0.03, the amount of fluorine supplied to the photoreceptor surface layer when the toner is developed is small, thus weakening the effects described in (Advantage 1 of fluorine content) and (Advantage 2 of fluorine content) above. On the other hand, if F / Al is greater than 0.70, the supply of fluorine to the surface layer increases, worsening the balance of the three lubricants with different charge properties. As a result, the effects described in (Advantages of having three lubricants: surface layer abrasive particles, hydrotalcite particles, and fluorine) and (Behavior of the three lubricants on the print density and image density of printed images during repeated use) above are weakened.

[0160] In line analysis using STEM-EDS analysis, it is preferable that fluorine is present inside the hydrotalcite particles.

[0161] Because hydrotalcite particles contain fluorine, fluorine is supplied to the photoreceptor in exchange for the adsorption of discharge products due to ion exchange. As a result, the supply of fluorine to the photoreceptor becomes more appropriate in conjunction with the discharge to the photoreceptor due to repeated use. Therefore, the balance of the three lubricants with different charge properties is improved, and the effects described above (the advantages of having three lubricants: surface layer abrasive particles, hydrotalcite particles, and fluorine) and (the behavior of the three lubricants on the print density and image density of printed images during repeated use) are enhanced.

[0162] <Method for identifying hydrotalcite particles> The hydrotalcite particles, which are external additives, can be identified by combining shape observation using a scanning electron microscope (SEM) and elemental analysis using energy-dispersive X-ray spectroscopy (EDS). Using a scanning electron microscope "S-4800" (product name; manufactured by Hitachi, Ltd.), toner is observed in a field of view magnified up to 50,000 times. The toner particle surface is focused to observe the external additive to be identified. EDS analysis is performed on the external additive to be identified, and hydrotalcite particles can be identified from the type of elemental peaks. If elemental peaks are observed for at least one metal selected from the group consisting of Mg, Zn, Ca, Ba, Ni, Sr, Cu, and Fe, which are metals that can constitute hydrotalcite particles, and for at least one metal selected from the group consisting of Al, B, Ga, Fe, Co, and In, the presence of hydrotalcite particles containing the two aforementioned metals can be inferred. A sample of hydrotalcite particles, inferred from EDS analysis, is prepared separately, and its shape is observed by SEM and then subjected to EDS analysis. The analysis results of the sample are compared with those of the target particle to determine whether or not it is a hydrotalcite particle.

[0163] <Method for measuring the percentage of hydrotalcite particles (b) in toner> The percentage b [mass%] of hydrotalcite particles in the toner can be quantified using X-ray fluorescence analysis and a calibration curve created from standard samples. The measurement of X-ray fluorescence for each element is in accordance with JIS K 0119-1969, and is specifically as follows.

[0164] The measurement equipment used is the wavelength-dispersive X-ray fluorescence analyzer "Axios" (PANalytical), and its accompanying dedicated software "SuperQ ver.4.0F" (PANalytical) for setting measurement conditions and analyzing measurement data. Rh is used as the anode of the X-ray tube, the measurement atmosphere is vacuum, the measurement diameter (collimator mask diameter) is 27 mm, and the measurement time is 10 seconds. Furthermore, a proportional counter (PC) is used for measuring light elements, and a scintillation counter (SC) is used for measuring heavy elements.

[0165] For the measurement sample, approximately 4g of toner was placed in a dedicated aluminum ring for pressing, flattened, and then molded into pellets approximately 2mm thick and 39mm in diameter by pressurizing it at 20MPa for 60 seconds using a tablet molding compressor. The tablet molding compressor used was the "BRE-32" manufactured by Maekawa Testing Machinery Co., Ltd.

[0166] Measurements are performed under the above conditions, the element is identified based on the peak position of the obtained X-rays, and its concentration is calculated from the count rate (unit: cps), which is the number of X-ray photons per unit time.

[0167] To 100 parts by mass of toner particles, add 0.10 parts by mass of a separately prepared hydrotalcite particle standard and mix thoroughly using a coffee grinder. Similarly, mix 0.20 parts by mass and 0.50 parts by mass of hydrotalcite particles with toner particles, respectively, and use these as calibration curve samples.

[0168] For each sample, the count rate (in cps) derived from the metal elements in the hydrotalcite is measured. The acceleration voltage and current of the X-ray generator are set to 24 kV and 100 mA, respectively. A linear calibration curve is obtained by plotting the obtained X-ray count rate on the vertical axis and the amount of hydrotalcite particles added to each calibration sample on the horizontal axis.

[0169] Next, the toner to be analyzed is pelletized using a tablet molding and compression machine as described above, and the counting rate of metal elements in the hydrotalcite is measured. Then, the percentage b [mass%] of hydrotalcite particles in the toner is determined from the calibration curve described above.

[0170] <Method for measuring the elemental ratios of polyvalent metal elements in toner particles and hydrotalcite particles> The following describes the STEM-EDS analysis according to the present invention. The elemental ratios of polyvalent metal elements in toner particles and hydrotalcite particles are measured by EDS mapping of the toner using a scanning transmission electron microscope (STEM). EDS mapping provides spectral data for each pixel in the analysis area. By using a silicon drift detector with a large detection area, EDS mapping can be measured with high sensitivity. By performing statistical analysis on the spectral data of each pixel obtained through EDS mapping measurements, it is possible to obtain principal component mappings by extracting pixels with similar spectra, enabling component-specific mapping.

[0171] The sample for observation is prepared using the following procedure. 0.5g of toner is weighed and placed in an 8mm diameter cylindrical mold. Using a Newton press, it is subjected to a load of 40kN for 2 minutes to produce a cylindrical toner pellet with a diameter of 8mm and a thickness of approximately 1mm. 200nm thick and thin sections are then prepared from the toner pellet using an ultramicrotome (Leica FC7).

[0172] STEM-EDS analysis was performed using the following equipment and under the following conditions. Measurement equipment used: Scanning transmission electron microscope; JEOL JEM-2800 Measurement equipment used 2: EDS detector; JEOL JED-2300T Dry SD100GV detector (detection element area: 100 mm²) 2 ) Measurement equipment used 3: EDS analyzer; Thermo Fisher Scientific NORAN System 7 (Conditions for STEM-EDS) • STEM acceleration voltage: 200kV ·Magnification: 20,000x • Probe size: 1nm STEM image size: 1024 x 1024 pixels (to acquire EDS elemental mapping images at the same location). EDS mapping size: 256 x 256 pixels, Dwell time: 30 μs, Number of integrations: 100 frames The ratio of polyvalent metal elements in toner particles and the ratio of each element in hydrotalcite particles were calculated based on multivariate analysis as follows.

[0173] The following describes the filter fitting analysis according to the present invention. EDS mapping was obtained using the STEM-EDS analyzer described above. Next, the collected spectral mapping data was subjected to multivariate analysis using the COMPASS (PCA) mode in the NORAN System7 measurement command described above, and a principal component map image was extracted. The settings were as follows: • Kernel size: 3x3 • Quantitative map setting: High (slow) • Filter fit type: High precision (slow) Simultaneously, this operation calculates the area ratio of each extracted principal component within the EDS measurement field. Quantitative analysis of the obtained EDS spectra of each principal component was performed using the Cliff-Lorrimer method. The distinction between toner particles and hydrotalcite particles is made based on the quantitative analysis results of the obtained STEM-EDS main component mapping. Hydrotalcite particles can be identified based on particle size, shape, content of polyvalent metals such as aluminum and magnesium, and their respective ratios. Furthermore, if fluorine is present in hydrotalcite particles by the following means, those particles can be determined to be hydrotalcite particles containing fluorine.

[0174] (Method for analyzing fluorine contained in hydrotalcite particles) Based on the mapping data obtained by STEM-EDS analysis using the method described above, the fluorine content in hydrotalcite particles will be analyzed. If the EDS spectrum obtained from the principal component map image of the particle extracted by COMPASS shows a fluorine peak intensity of 1.5 times or more than the background intensity, it is determined that the particle contains fluorine.

[0175] (Method for analyzing fluorine and aluminum inside hydrotalcite particles) Based on the mapping data obtained by STEM-EDS analysis using the method described above, the fluorine and aluminum content inside the hydrotalcite particles will be analyzed. Specifically, EDS line analysis will be performed in the direction normal to the surface of the particles to analyze the fluorine and aluminum present inside. A schematic diagram of line analysis is shown in Figure 2(a). Line analysis is performed on toner particle 1 and hydrotalcite particle 3 adjacent to toner particle 2, in the direction normal to the outer circumference of hydrotalcite particle 3, i.e., in the direction of 5. Note that 4 indicates the boundary of the toner particle. Select the area containing hydrotalcite particles in the acquired STEM image using the rectangular selection tool, and perform line analysis under the following conditions. The area containing the relevant particles in the acquired STEM image was selected using the rectangular selection tool, and line analysis was performed under the following conditions. (Line analysis conditions) ·STEM magnification; 800,000x Line length: 200nm Line width: 30nm • Number of line divisions: 100 points (intensity measured every 2 nm) If the elemental peak intensity of fluorine or aluminum is 1.5 times or more than the background intensity in the EDS spectrum of hydrotalcite particles, and the elemental peak intensity of fluorine or aluminum at both ends of the hydrotalcite particle (points a and b in Figure 2(a)) in the line analysis does not exceed 3.0 times the peak intensity at point c, then it is determined that the element is contained inside the hydrotalcite particle. Point c is defined as the midpoint of line segment ab (i.e., the midpoint of both ends mentioned above). Examples of X-ray intensities of fluorine and aluminum obtained by line analysis are shown in Figures 2(b) and 2(c). When hydrotalcite particles contain fluorine and aluminum internally, the X-ray intensity graph normalized by peak intensity shows the shape shown in Figure 2(b). When hydrotalcite particles contain fluorine derived from the surface treatment agent, the X-ray intensity graph normalized by peak intensity shows peaks near points a and b at both ends of the fluorine graph, as shown in Figure 2(c). By confirming the X-ray intensities derived from fluorine and aluminum in line analysis, it is possible to confirm that hydrotalcite particles contain fluorine and aluminum internally.

[0176] (Method for calculating the elemental ratio (ratio of atomic concentrations) of magnesium and aluminum, Mg / Al) Based on the mapping data obtained by STEM-EDS analysis using the method described above, the elemental ratio (ratio of atomic number concentrations) of magnesium to aluminum in hydrotalcite particles, Mg / Al, is calculated. In the principal component map image of hydrotalcite particles extracted using the method described above, the elemental amounts (atomic number concentrations) of magnesium and aluminum are quantified, and the elemental ratio (ratio of atomic number concentrations) of magnesium to aluminum is calculated. The mapping data is acquired from multiple fields of view, and the elemental ratio of magnesium to aluminum in hydrotalcite particles is calculated by taking the arithmetic mean of 100 or more of the relevant particles.

[0177] (Method for calculating the elemental ratio (ratio of atomic concentrations) of fluorine and aluminum, F / Al) Based on the mapping data obtained by SETM-EDS analysis using the method described above, the elemental ratio (ratio of atomic number concentrations) F / Al of fluorine and aluminum in hydrotalcite particles is calculated. In the principal component map image of hydrotalcite particles extracted using the method described above, the elemental amounts (atomic number concentrations) of fluorine and aluminum are quantified, and the elemental ratio (ratio of atomic number concentrations) of fluorine and aluminum is calculated. The mapping data is acquired from multiple fields of view, and the elemental ratio (ratio of atomic number concentrations) F / Al of fluorine and aluminum in hydrotalcite particles is calculated by taking the arithmetic mean of 100 or more of the relevant particles.

[0178] <Method for measuring the number-average particle size of hydrotalcite particles> The number-average particle size of hydrotalcite particles is measured using a scanning electron microscope "S-4800" (product name; manufactured by Hitachi, Ltd.). The toner to which the external additive has been added is observed, and the major axis of 100 randomly selected primary particles of the external additive is measured in a field of view magnified up to 200,000 times to determine the number-average particle size. The observation magnification is adjusted as appropriate depending on the size of the external additive. Here, particles that appear as a single particle during observation are considered primary particles.

[0179] <Method for measuring the median diameter based on toner volume> The median diameter based on toner volume is calculated as follows. The measuring device used is the "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter), a precision particle size distribution analyzer using the pore electrical resistance method equipped with a 100 μm aperture tube. The included dedicated software, "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter), is used to set the measurement conditions and analyze the measurement data. The measurement is performed using 25,000 effective measurement channels.

[0180] The electrolytic aqueous solution used for measurement is prepared by dissolving special grade sodium chloride in deionized water to a concentration of approximately 1% by mass; for example, "ISOTON II" (manufactured by Beckman Coulter) can be used.

[0181] Before performing measurements and analyses, configure the dedicated software as follows. In the "Change Standard Measurement Method (SOMME)" screen of the dedicated software, set the total count in control mode to 50,000 particles, the number of measurements to 1, and the Kd value to the value obtained using "Standard Particle 10.0 μm" (manufactured by Beckman Coulter). Press the "Measure Threshold / Noise Level Button" to automatically set the threshold and noise level. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check "Flush aperture tube after measurement". In the "Pulse to Particle Size Conversion Settings" screen of the dedicated software mentioned above, set the bin spacing to logarithmic particle size, the particle size bins to 256 particle size bins, and the particle size range from 2 μm to 60 μm.

[0182] The specific measurement method is as follows: (1) Place approximately 200 mL of the electrolytic solution into a 250 mL round-bottom glass beaker specifically designed for the Multisizer 3, set it on the sample stand, and stir the mixture with the stirrer rod at 24 revolutions per second in a counterclockwise direction. Then, use the "Aperture Tube Flash" function of the dedicated software to remove any dirt and air bubbles from inside the aperture tube. (2) Place approximately 30 mL of the electrolytic aqueous solution into a 100 mL flat-bottomed glass beaker. Add approximately 0.3 mL of a diluted solution of "Contaminon N" (a 10% by mass aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) diluted to approximately 3 times its original volume with deionized water as a dispersant. (3) Prepare an "Ultrasonic Dispersion System Tetra150" (manufactured by Nikko Bios Co., Ltd.) with an electrical output of 120W, which incorporates two oscillators with an oscillation frequency of 50kHz, with their phases shifted by 180 degrees. Add approximately 3.3L of deionized water to the water tank of the ultrasonic disperser, and add approximately 2mL of Contaminon N to this water tank. (4) Place the beaker from (2) into the beaker fixing hole of the ultrasonic disperser and operate the ultrasonic disperser. Then, adjust the height of the beaker so that the resonance state of the liquid surface of the electrolytic aqueous solution inside the beaker is maximized. (5) While irradiating the electrolytic aqueous solution in the beaker described in (4) with ultrasound, add approximately 10 mg of toner to the electrolytic aqueous solution in small amounts and disperse it. Continue the ultrasonic dispersion treatment for another 60 seconds. During ultrasonic dispersion, adjust the water temperature in the tank to be between 10°C and 40°C as appropriate. (6) Using a pipette, the electrolytic aqueous solution (5) containing the dispersed toner is dropped into the round-bottom beaker (1) placed in the sample stand, and the concentration is adjusted to approximately 5%. The measurement is then continued until the number of particles measured reaches 50,000. (7) The measurement data is analyzed using the dedicated software attached to the device, and the volume-based median diameter is calculated.

[0183] [Process cartridges, electrophotographic equipment] The process cartridge of the present invention comprises an electrophotographic photoreceptor, toner, and a developing member that supplies toner to the electrophotographic photoreceptor, and is characterized by being detachable from the main body of an electrophotographic apparatus. Furthermore, the electrophotographic apparatus of the present invention is characterized by having the above-mentioned process cartridge.

[0184] Figure 1 shows an example of a schematic configuration of an electrophotographic apparatus having an electrophotographic photoreceptor, toner, and a process cartridge equipped with a developing component. 101 is a cylindrical electrophotographic photoreceptor, which is rotated at a predetermined peripheral speed in the direction of the arrow around axis 102. The surface of the electrophotographic photoreceptor 101 is charged to a predetermined positive or negative potential by a charging member 103. In the figure, a roller charging method using a roller-type charging member is shown, but other charging methods such as corona charging, proximity charging, and injection charging may also be used. Exposure light 104 is irradiated onto the surface of the charged electrophotographic photoreceptor 101 from an exposure member (not shown), and an electrostatic latent image corresponding to the desired image information is formed. The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 101 is developed with toner contained in a developing member 105, and a toner image is formed on the surface of the electrophotographic photoreceptor 101. The toner image formed on the surface of the electrophotographic photoreceptor 101 is transferred to a transfer material 107 by a transfer member 106. The transfer material 107 with the transferred toner image is transported to a fixing means 108, where the toner image is fixed and printed out outside the electrophotographic device. The electrophotographic apparatus may have a cleaning member 109 for removing toner and other deposits remaining on the surface of the electrophotographic photoreceptor 101 after transfer. Alternatively, a so-called cleanerless system may be used in which the deposits are removed by a developing member or the like without a separate cleaning member. The electrophotographic apparatus may also have a static elimination mechanism for removing static electricity from the surface of the electrophotographic photoreceptor 101 with pre-exposure light 110 from a pre-exposure member (not shown). Furthermore, guide members 112 such as rails may be provided for attaching and detaching the process cartridge 111 of the present invention to the electrophotographic apparatus body.

[0185] The process cartridge of the present invention can be used in laser beam printers, LED printers, photocopiers, and the like.

[0186] <Surface layer of the electrophotographic photoreceptor held in the process cartridge and external additives for the toner> In the process cartridge of the present invention, the electrophotographic photoreceptor must be formed by polymerizing a composition containing at least one monofunctional (meth)acrylic compound selected from the group consisting of monofunctional (meth)acrylic monomers and monofunctional (meth)acrylic oligomers, and at least one trifunctional or greater (meth)acrylic compound selected from the group consisting of trifunctional or greater (meth)acrylic monomers and trifunctional or greater (meth)acrylic oligomers, as described above for the electrophotographic photoreceptor.

[0187] Furthermore, in the process cartridge of the present invention, the toner contains hydrotalcite particles as an external additive, as described above under [Toner], and in filter fitting analysis in STEM-EDS analysis, the hydrotalcite particles must contain fluorine. Furthermore, it is preferable that the electrophotographic photoreceptor and / or toner have the respective characteristics described above for [electrophotographic photoreceptor] and / or [toner].

[0188] In particular, in the process cartridge of the present invention, when the content ratio of a monofunctional (meth)acrylic compound to a trifunctional or more (meth)acrylic compound in the composition of the electrophotographic photoreceptor surface layer is a [mass%], and the content ratio of hydrotalcite particles of the toner external additive to the toner is b [mass%], it is preferable that a and b satisfy the relationship shown in the following formula (E1). 100≦a / b≦4000 Formula (E1) When a and b satisfy the above equation, the balance of supply of lubricants with three different charge polarities to the electrophotographic photoreceptor surface layer is improved, and the effects described above (the advantages of having three lubricants: surface layer abrasive particles, hydrotalcite particles, and fluorine) and (the behavior of the three lubricants on the print density and image density of printed images during repeated use) are strengthened. On the other hand, if a / b is less than 100, the amount of abrasive particles containing nonpolar ester bonds decreases relative to the amount of hydrotalcite particles, and the above balance is more likely to be disrupted. On the other hand, if a / b is greater than 4000, the amount of abrasive particles containing nonpolar ester bonds increases relative to the amount of hydrotalcite particles, and the above balance is also more likely to be disrupted.

[0189] Furthermore, it is preferable that the process cartridge of the present invention satisfies the above formula (E1) and simultaneously satisfies the following three characteristics described in <External Additives> above. b is between 0.01% by mass and 3.0% by mass. • Hydrotalcite particles must contain magnesium and aluminum in filter fitting analysis during STEM-EDS analysis, and the elemental ratio (ratio of atomic concentrations) of magnesium to aluminum (Mg / Al) must be between 1.5 and 4.0. • In filter fitting analysis using STEM-EDS analysis, the elemental ratio (ratio of atomic concentrations) F / Al of fluorine to aluminum in the hydrotalcite particles is between 0.03 and 0.70.

[0190] When all four of these characteristics are met, the balance of supply between negatively charged fluorine, positively charged hydrotalcite particles, and nonpolar abrasive particles is improved, further enhancing the effects described above (the advantages of having three lubricants: abrasive particles on the surface layer, hydrotalcite particles, and fluorine) and (the behavior of the three lubricants on the print density and image density of printed images during repeated use). [Examples]

[0191] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited in any way by the following examples, unless it exceeds the gist of the invention. In the following examples, "parts" refers to mass unless otherwise specified.

[0192] The film thickness of each layer in the electrophotographic photoreceptors of the examples and comparative examples was determined, with the exception of the charge generation layer, by using an eddy current film thickness meter (Fischerscope®, manufactured by Fischer Instruments) or by converting the specific gravity from the mass per unit area. The film thickness of the charge generation layer was determined as follows: The Macbeth density value was measured by pressing a spectrophotometer (product name: X-Rite504 / 508, manufactured by X-Rite) against the surface of the electrophotographic photoreceptor. The film thickness was calculated from the measured Macbeth density value using a calibration curve previously obtained from the Macbeth density value and film thickness measurements obtained by cross-sectional SEM image observation.

[0193] <Preparation of coating solution for the undercoat layer> 100 parts of rutile-type titanium dioxide particles (product name: MT-600B, average primary particle size: 50 nm, manufactured by Teika) were mixed with 500 parts of toluene and stirred. 5.0 parts of vinyltrimethoxysilane (product name: KBM-1003, manufactured by Shin-Etsu Chemical) were added and the mixture was stirred for 8 hours. Subsequently, the toluene was removed by vacuum distillation, and the mixture was dried at 120°C for 3 hours to obtain rutile-type titanium dioxide particles surface-treated with vinyltrimethoxysilane. Next, 18 parts of rutile-type titanium dioxide particles surface-treated with the vinyltrimethoxysilane mentioned above, 4.5 parts of N-methoxymethylated nylon (product name: Trezin EF-30T, manufactured by Nagase ChemteX), and 1.5 parts of copolymerized nylon resin (product name: Amiran (trademark) CM8000, manufactured by Toray) were added to a mixed solvent of 90 parts methanol and 60 parts 1-butanol to prepare a dispersion. This dispersion was then dispersed using 1.0 mm diameter glass beads in a vertical sand mill for 5 hours to prepare a coating solution for the undercoat layer.

[0194] <Preparation of coating solution for charge generation layer> [Example of combination] 100 g of α-chloronaphthalene, 5.0 g of o-phthalodinitrile, and 2.0 g of titanium tetrachloride were heated and stirred at 200°C for 3 hours, then cooled to 50°C. The precipitated crystals were filtered off to obtain a paste of dichlorotitanium phthalocyanine. Next, this paste was washed with 100 mL of N,N-dimethylformamide heated to 100°C, followed by two washes with 100 mL of methanol at 60°C, and then filtered. The obtained paste was further stirred in 100 mL of deionized water at 80°C for 1 hour, and filtered to obtain 4.3 g of blue titanyl phthalocyanine pigment.

[0195] [Milling example] 0.5 parts of the titanylphthalocyanine pigment obtained in the synthesis example, 10 parts of tetrahydrofuran, and 15 parts of 0.9 mm diameter glass beads were milled for 48 hours at a cooling water temperature of 18°C ​​using a sand mill (K-800, manufactured by Igarashi Machinery Manufacturing (now AIMEX), disk diameter 70 mm, 5 disks). This was carried out under conditions of disk rotations of 500 revolutions per minute. The resulting solution was filtered through a filter (product number: N-NO.125T, pore size: 133 μm, manufactured by NBC Meshtec) to remove the glass beads. 30 parts of tetrahydrofuran were added to this solution, and it was filtered again. The filter residue on the filter was thoroughly washed with methanol and water. The washed residue was then vacuum dried to obtain 0.45 parts of titanylphthalocyanine pigment. The obtained pigment showed a strong peak at a Bragg angle of 2θ of 27.2°±0.3° in the X-ray diffraction spectrum using CuKα rays.

[0196] Twelve parts of titanyl phthalocyanine pigment obtained from the milling example, ten parts of polyvinyl butyral (product name: S-Rec BX-1, manufactured by Sekisui Chemical Co., Ltd.), fifty-eight parts of cyclohexanone, and forty-two parts of 0.9 mm diameter glass beads were dispersed using a sand mill (K-800, manufactured by Igarashi Machinery Manufacturing Co., Ltd. (now AIMEX), with a disc diameter of 70 mm and five discs) for four hours at a cooling water temperature of 18°C. This process was carried out under conditions of the disc rotating at 1,800 revolutions per minute. After removing the glass beads, a coating solution for the charge generation layer was prepared by adding 369 parts of cyclohexanone and 527 parts of ethyl acetate to the dispersion.

[0197] <Preparation of coating solution for charge transport layer> As a charge transport material, the following formula (A4) [ka] 30 parts of the charge transport material shown, The following formula (A5) [ka] 50 parts of the charge transport material shown, A coating solution for the charge transport layer was prepared by dissolving 100 parts of polycarbonate (product name: Yupiron Z-400, manufactured by Mitsubishi Engineering Plastics) in 210 parts of orthoxylene, 360 parts of methyl benzoate, and 140 parts of dimethoxymethane.

[0198] <Preparation of protective coating solution> [Preparation of protective coating solution 1] The following formula (A6) [ka] Five parts of a monofunctional (meth)acrylic compound shown, The following formula (A7) [ka] 100 parts of a trifunctional or more (meth)acrylic compound as shown, 5.3 parts of a photopolymerization initiator (product name: Irgacure 184, manufactured by Ciba Specialty Chemicals) and 13.2 parts of alumina particles (product name: AA03 (primary particle size 0.3 μm), manufactured by Sumitomo Chemical) were dissolved in 537 parts of tetrahydrofuran. The resulting solution was analyzed by chromatography and high-precision mass spectrometry, yielding the following formula (A8). [ka] It was confirmed that the diphenylamine compound shown by was contained at a mass ratio of 5 ppm with respect to the solid content. The diphenylamine compound was added so that the mass ratio became 500 ppm, and the coating liquid 1 for the protective layer having a solid content of 23% by mass was prepared.

[0199] [Preparation of Coating Liquids 2 to 77 for Protective Layer] In the preparation of the coating liquid 1 for the protective layer, as shown in Tables 1 and 2, the structural formula and parts by mass of the monofunctional (meth)acrylic compound, the structural formula and parts by mass of the trifunctional or higher (meth)acrylic compound, the mass ratio after the addition of the diphenylamine compound, and the particle type and parts by mass of the particles A containing metal atoms were changed to prepare the coating liquids 2 to 77 for the protective layer. The amount of the photopolymerization initiator (trade name: Irgacure 184, manufactured by Ciba Specialty Chemicals) was appropriately adjusted so as to be 5% by mass with respect to the (meth)acrylic compound. The amount of tetrahydrofuran was appropriately adjusted so that the solid content became 23% by mass. For the coating liquids 45, 48, and 74 for the protective layer, two types of trifunctional or higher (meth)acrylic compounds were used. For the coating liquids 64 to 71 for the protective layer, the particles A containing metal atoms were not used. For the coating liquids 72 to 74 for the protective layer, the monofunctional (meth)acrylic compound was not used. For the coating liquids 75 to 77 for the protective layer, a difunctional (meth)acrylic compound was used instead of the monofunctional (meth)acrylic compound.

[0200] The structural formulas (A9) to (A33) in Tables 1 and 2 are shown below. [Chemical Formula] [Chemical Formula] [Chemical Formula] [Chemical Formula] [Chemical Formula] [Chemical Formula]

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[0201] In Tables 1 and 2, "titanium oxide" refers to titanium oxide particles (product name: JR-405, average primary particle size: 210 nm, manufactured by Teika). "Tin oxide" refers to tin oxide particles (average primary particle size: 20 nm, manufactured by CIK Nanotech). "Barium sulfate" refers to barium sulfate particles (product name: Pastran PC1, manufactured by Mitsui Mining & Smelting Co., Ltd.).

[0202] [Table 1]

[0203] [Table 2]

[0204] <Manufacturing of electrophotographic photoconductors> (Photoreceptor manufacturing example 1) An aluminum cylinder (JIS-A3003, aluminum alloy) with a length of 260.5 mm and a diameter of 30 mm was obtained as a support using a manufacturing method that included extrusion and drawing processes. A coating solution for the undercoat layer was applied to this support by immersion to form a coating film, and the coating film was heated and dried at 100°C for 10 minutes to form an undercoat layer with a thickness of 4.0 μm. Next, the coating solution for the charge generation layer was applied to the above-mentioned undercoat layer by immersion to form a coating film, and the coating film was heated and dried at 100°C for 10 minutes to form a charge generation layer with a thickness of 0.22 μm. Next, a coating solution for the charge transport layer was applied to the charge generating layer by immersion to form a coating film, and the coating film was heated and dried at 120°C for 60 minutes to form a charge transport layer with a thickness of 23 μm. Next, protective coating liquid 1 is applied to the charge transport layer by immersion to form a coating film, and the coating film is heated and dried at 40°C for 3 minutes. After that, it is heated and dried with a metal hydro lamp (irradiation intensity: 450 mW / cm²). 2A protective layer with a thickness of 3.8 μm was formed by light irradiation (irradiation time: 50 seconds) followed by heating and drying at a temperature of 135 degrees Celsius for 25 minutes. The heat treatment of each coating layer was carried out using an oven set to a specific temperature. In this manner, a cylindrical (drum-shaped) photoreceptor 1 was manufactured.

[0205] Tables 3 and 4 show the results of measuring the content ratio of monofunctional (meth)acrylic compounds to trifunctional or more functional (meth)acrylic compounds: a [mass%], the elastic deformation rate of the surface, the content ratio of diphenylamine compounds to the surface layer, and the content ratio of particles A containing metal atoms to the surface layer, respectively, using the methods described in <Method for identifying monofunctional (meth)acrylic compounds and trifunctional or more functional (meth)acrylic compounds>, ​​<Measurement of elastic deformation rate>, <Method for identifying diphenylamine compounds>, ​​and <Method for identifying particles A containing metal atoms> above for the photoreceptor obtained at this time.

[0206] (Photoreceptor manufacturing examples 2-77) Photoreceptors 2-77 were manufactured in the same manner as in Photoreceptor Manufacturing Example 1, except that protective layer coating solution 1 was changed to protective layer coating solutions 2-77. In addition, similar to Photoreceptor 1, the content ratio of monofunctional (meth)acrylic compound to trifunctional or more (meth)acrylic compounds: a [mass %], the elastic deformation rate of the surface, the content ratio of diphenylamine compound to the surface layer, and the content ratio of particles A containing metal atoms to the surface layer were measured. The results are shown in Tables 3 and 4. However, for Photoreceptor Manufacturing Examples 11-16, the irradiation intensity of the metal hydro lamp was appropriately adjusted to achieve the elastic deformation rates shown in Tables 3 and 4.

[0207] [Table 3]

[0208] [Table 4]

[0209] <Toner Manufacturing> [Example of preparation of resin particle dispersion] 76.0 parts of styrene 22.7 parts butyl acrylate 1.3 parts acrylic acid • 3.2 parts n-lauryl mercaptan The above materials were placed in a container and stirred to mix. To this solution, 1.5 parts of Neogen RK (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 150.0 parts of an aqueous solution of deionized water were added and dispersed. While slowly stirring for another 10 minutes, an aqueous solution of 0.3 parts potassium persulfate and 10.0 parts deionized water was added. After nitrogen purging, emulsion polymerization was carried out at 70°C for 6 hours. After polymerization was complete, the reaction solution was cooled to room temperature, and deionized water was added to obtain a resin particle dispersion with a solid content of 12.5% ​​by mass and a glass transition temperature of 58°C. The particle size distribution of the resin particles contained in this dispersion was measured using a particle size analyzer (Horiba, Ltd., LA-920), and the number-average particle size of the contained resin particles was 0.2 μm. Furthermore, no coarse particles larger than 1 μm were observed.

[0210] [Example of preparation of release agent dispersion 1] 100.0 parts of behenyl behenate (melting point: 72.1°C) and 15.0 parts of Neogen RK were mixed with 385.0 parts of deionized water and dispersed for approximately 1 hour using a wet jet mill JN100 (manufactured by Jokoh Co., Ltd.) to obtain mold release agent dispersion 1. The wax concentration of mold release agent dispersion 1 was 20.0% by mass. The particle size distribution of the mold release agent particles contained in this dispersion 1 was measured using a particle size analyzer (Horiba, Ltd., LA-920), and the number-average particle size of the contained mold release agent particles was 0.35 μm. Furthermore, no coarse particles larger than 1 μm were observed.

[0211] [Example of preparation of release agent dispersion 2] 100.0 parts of hydrocarbon wax HNP-9 (manufactured by Nippon Seiro Co., Ltd., melting point: 75.5°C) and 15 parts of Neogen RK were mixed with 385.0 parts of ion-exchanged water and dispersed for approximately 1 hour using a wet jet mill JN100 (manufactured by Joko Co., Ltd.) to obtain mold release agent dispersion 2. The wax concentration of mold release agent dispersion 2 was 20.0% by mass. The particle size distribution of the mold release agent particles contained in this dispersion 2 was measured using a particle size analyzer (manufactured by Horiba, Ltd., LA-920), and the number-average particle size of the contained mold release agent particles was 0.35 μm. Furthermore, no coarse particles exceeding 1 μm were observed.

[0212] [Example of preparation of a colorant dispersion] As a coloring agent, 50.0 parts of copper phthalocyanine (pigment blue 15:3) and 5.0 parts of Neogen RK were mixed with 200.0 parts of deionized water and dispersed for approximately 1 hour using a wet jet mill JN100 to obtain coloring agent dispersion 1. The solid content concentration of coloring agent dispersion 1 was 20.0% by mass. The particle size distribution of the coloring agent particles contained in this dispersion 1 was measured using a particle size analyzer (Horiba, Ltd., LA-920), and the number-average particle size of the contained coloring agent particles was 0.20 μm. Furthermore, no coarse particles larger than 1 μm were observed.

[0213] (Method for manufacturing toner particles) ·Resin particle dispersion: 265.0 parts • Release agent dispersion 1:10.0 parts • Release agent dispersion 2:8.0 parts • Colorant dispersion: 8.0 parts As part of the core formation process, each of the above materials was placed in a round stainless steel flask and mixed. Subsequently, the mixture was dispersed for 10 minutes at 5000 r / min using a homogenizer (IKA Ultra-Turrax T50). While stirring, the temperature inside the container was adjusted to 30°C, and a 1 mol / L sodium hydroxide aqueous solution was added to adjust the pH to 8.0. As a coagulant, an aqueous solution of 0.25 parts aluminum chloride dissolved in 10.0 parts deionized water was added over 10 minutes while stirring at 30°C. After standing for 3 minutes, the temperature was raised to 60°C to generate coagulated particles (core formation). The volume-based median diameter of the formed coagulated particles was conveniently confirmed using a "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter). When the volume-based median diameter reached 7.0 μm, a 1 mol / L sodium hydroxide aqueous solution was added to adjust the pH to 9.0, and then the temperature was raised to 95°C to sphericalize the coagulated particles.

[0214] (Preparation of hydrotalcite particles 1) A mixed aqueous solution of 1.03 mol / L magnesium chloride and 0.239 mol / L aluminum sulfate (Solution A), an aqueous solution of 0.753 mol / L sodium carbonate (Solution B), and an aqueous solution of 3.39 mol / L sodium hydroxide (Solution C) were prepared. Next, solutions A, B, and C were added to the reaction vessel using a metering pump at a flow rate such that the volume ratio of A:B was 4.5:1. Solution C was used to maintain the pH of the reaction mixture in the range of 9.3 to 9.6, and the reaction was carried out at a temperature of 40°C to generate a precipitate. After filtration and washing, the mixture was re-emulsified with deionized water to obtain the hydrotalcite slurry. The hydrotalcite concentration in the obtained hydrotalcite slurry was 5.6% by mass. The obtained hydrotalcite slurry was vacuum-dried overnight at 40°C. NaF was dissolved in deionized water to a concentration of 100 mg / L, and a solution was prepared with pH 7.0 using 1 mol / L HCl or 1 mol / L NaOH. Dried hydrotalcite was added to this solution to a concentration of 0.1% (w / v%). The mixture was stirred at a constant speed for 48 hours using a magnetic stirrer, without causing sedimentation. After that, it was filtered through a 0.5 μm pore size membrane filter and washed with deionized water. The obtained hydrotalcite was vacuum-dried overnight at 40°C, and then subjected to crushing treatment.

[0215] (Preparation of hydrotalcite particles 2-31) Except for conveniently adjusting the volume ratio of solution A to solution B and the concentration of the NaF aqueous solution, (hydrotalcite particles 2-31) were obtained in the same manner as the production example of (hydrotalcite particle 1).

[0216] (Hydrotalcite particles 32) A mixed aqueous solution of 1.03 mol / L magnesium chloride and 0.239 mol / L aluminum sulfate (Solution A), an aqueous solution of 0.753 mol / L sodium carbonate (Solution B), and an aqueous solution of 3.39 mol / L sodium hydroxide (Solution C) were prepared. Next, solutions A, B, and C were added to the reaction vessel using a metering pump at a flow rate such that the volume ratio of solution A to B was 4.5:1. Solution C was used to maintain the pH of the reaction mixture in the range of 9.3 to 9.6, and the reaction was carried out at a temperature of 40°C to produce a precipitate. After filtration and washing, the mixture was re-emulsified with deionized water to obtain the hydrotalcite slurry. The hydrotalcite in the obtained hydrotalcite slurry was 5.6% by mass. The obtained hydrotalcite slurry was kept at 95°C, and surface treatment was performed by adding 5 parts by mass of fluorosilicone oil to 95 parts by mass of solids. Subsequently, filtration and washing were performed, and the mixture was dried at 100°C for 24 hours. The mixture was then crushed using an atomizer mill (manufactured by Dalton Co., Ltd.) to obtain hydrotalcite particles (32).

[0217] (Preparation of hydrotalcite particles 33) (Hydrotalcite particle 33) was obtained in the same manner as in the example of (Hydrotalcite particle 1), except that ion-exchanged water was used instead of the NaF aqueous solution.

[0218] <Toner Manufacturing> (Toner manufacturing example 1) To 98.3 parts of the toner particles 1 obtained above, 0.2 parts of hydrotalcite particles 1 and 1.5 parts of silica particles (product name: RX200, primary mean particle size 12 nm, HMDS treated, manufactured by Nippon Aerosil) were added and mixed externally using FM10C (manufactured by Nippon Coke Industries Co., Ltd.). The external addition conditions were as follows: the lower blade was set to A0 blade, the distance from the deflector wall was set to 20 mm, the amount of toner particles to be charged was 2.0 kg, the rotation speed was 66.6 s⁻¹, the external addition time was 10 minutes, and the cooling water was cooled at a temperature of 20°C and a flow rate of 10 L / min. After that, the mixture was sieved with a mesh with a mesh opening of 200 μm to obtain toner 1.

[0219] (Toner manufacturing examples 2-41) In the manufacturing method of Toner Manufacturing Example 1, the hydrotalcite particles 1 were changed as shown in Table 5, and the amount of hydrotalcite particles was appropriately adjusted so that the hydrotalcite particle content ratio b [mass %] in the toner was the value shown in Table 5. Other than these changes, toners (2-41) were produced in the same manner as in Toner Manufacturing Example 1. However, hydrotalcite particles were not used in Toner Manufacturing Example 41. For the manufactured toners 1-41, whether or not fluorine was contained in the hydrotalcite particles contained in the toner was measured using the methods described in <Method for measuring the ratio of polyvalent metal elements in toner particles and each element in hydrotalcite particles> and (Method for analyzing fluorine contained in hydrotalcite particles). As a result, fluorine was found to be contained in the hydrotalcite particles contained in toners 1-39. Furthermore, for toners 1-39, the presence of fluorine inside the hydrotalcite particles was measured using the method described in (Analysis method for fluorine and aluminum inside hydrotalcite particles). As a result, fluorine was found inside the hydrotalcite particles contained in toners 1-31.

[0220] For manufactured toners 1 to 41, the content ratio of hydrotalcite particles in the toner, the elemental ratio (ratio of atomic number concentrations) of magnesium to aluminum (Mg / Al), and the elemental ratio (ratio of atomic number concentrations) of fluorine to aluminum (F / Al) were measured using the methods described in <Method for measuring the content ratio b of hydrotalcite in the toner>, (Method for calculating the elemental ratio (ratio of atomic number concentrations) of magnesium to aluminum (Mg / Al)), and (Method for calculating the elemental ratio (ratio of atomic number concentrations) of fluorine to aluminum (F / Al) above. The results are shown in Table 5.

[0221] [Table 5]

[0222] [evaluation] Examples 1-124 and Comparative Examples 1-10 were evaluated using the above photoreceptor manufacturing examples 1-77 and toner manufacturing examples 1-41. The evaluation was performed as follows. The results are shown in Tables 6-8.

[0223] <Evaluation device> For evaluation purposes, a Hewlett-Packard laser beam printer (product name: Laser Jet Enterprise M609dn) was prepared and modified to allow adjustment and measurement of process speed, voltage applied to the charging roller, image exposure amount, and transfer voltage. Furthermore, modifications were made to allow measurement of the drive current of the photoreceptor's rotation motor and to measure the increase ratio of the drive torque. For image output, the photoreceptors from photoreceptor manufacturing examples 1-77 and the toners from toner manufacturing examples 1-41 were installed in the process cartridge of the laser beam printer, and a test chart with a print ratio of 5% was output as a monochrome image.

[0224] <Evaluation of fluctuations in driving torque during durability> The charging potential was set to -500V and the exposure potential to -170V. Under normal temperature and humidity conditions (temperature 23.5°C, relative humidity 50%RH), the average driving torque of the initial 100 photoreceptors was measured. Next, the environment of the evaluation machine was continuously changed from a low temperature and low humidity environment (temperature 15°C, relative humidity 10%RH) to a high temperature and high humidity environment (temperature 32.5°C, relative humidity 80%RH) over a 10,000-sheet feeding cycle. The charging potential was also continuously changed from -400V to -600V over a 5,000-sheet feeding cycle, and the transfer potential was also continuously changed from +200V to +400V over a 250-sheet feeding cycle. A 100,000-sheet feeding endurance test was then performed. The drive torque of the last 100 photoreceptors was measured under normal temperature and humidity conditions (temperature 23.5°C, relative humidity 50%RH), and the average value was calculated. The ratio of the final drive torque to the initial drive torque was used as the evaluation value for durability drive torque fluctuation.

[0225] <Evaluation of endurance potential fluctuations> The exposure potential value after endurance testing was used as the evaluation value for the endurance potential fluctuation.

[0226] [Table 6]

[0227] [Table 7]

[0228] [Table 8] [Explanation of Symbols]

[0229] 101 Electrophotographic photoreceptor 102 axis 103 Charging means 104 Exposure light 105 Developing means 106 Transfer means 107 Transfer material 108 Fixing means 109 Cleaning methods 110 Pre-exposure light 111 Process Cartridge 112 Guidance methods

Claims

1. A process cartridge that is detachable from the main body of an electrophotographic apparatus, The process cartridge comprises an electrophotographic photoreceptor, toner, and a developing member that supplies the toner to the electrophotographic photoreceptor. The electrophotographic photoreceptor, A monofunctional (meth)acrylic compound selected from the group consisting of monofunctional (meth)acrylic monomers and monofunctional (meth)acrylic oligomers, A trifunctional (meth)acrylic compound selected from the group consisting of trifunctional (meth)acrylic monomers and trifunctional (meth)acrylic oligomers, The composition has a surface layer which is a polymerized film of a composition containing the following: The toner comprises toner particles and hydrotalcite particles as an external additive. In filter fitting analysis in STEM-EDS analysis, the hydrotalcite particles contain fluorine. A process cartridge characterized by the following features.

2. The process cartridge according to claim 1, wherein when the content ratio of the monofunctional (meth)acrylic compound in the composition to the trifunctional or more (meth)acrylic compound is a [mass%], a [mass%] is 20 to 500% by mass.

3. The process cartridge according to claim 2, wherein the elastic deformation rate of the surface layer is 35 to 50%.

4. The process cartridge according to any one of claims 1 to 3, wherein when the content ratio of the hydrotalcite particles in the toner is b [mass%], b [mass%] is 0.010 mass% or more and 3.000 mass% or less.

5. In filter fitting analysis in STEM-EDS analysis, the hydrotalcite particles contain magnesium and aluminum, In filter fitting analysis in STEM-EDS analysis, the elemental ratio (ratio of atomic concentrations) of magnesium to aluminum, Mg / Al, is 1.5 to 4.

0. A process cartridge according to any one of claims 1 to 4.

6. The process cartridge according to claim 5, wherein, in the filter fitting analysis in STEM-EDS analysis, the elemental ratio (ratio of atomic concentrations) F / Al of fluorine to aluminum in the hydrotalcite particles is 0.03 to 0.

70.

7. The process cartridge according to any one of claims 1 to 6, wherein fluorine is present inside the hydrotalcite particles in line analysis in STEM-EDS analysis.

8. A process cartridge according to any one of claims 1 to 7, wherein a [mass%] is the content ratio of the monofunctional (meth)acrylic compound in the composition to the trifunctional or more (meth)acrylic compound, and b [mass%] is the content ratio of the hydrotalcite particles in the toner to the toner, and a and b satisfy the relationship shown in the following formula (E1). 100≦a / b≦4000 Formula (E1)

9. The process cartridge according to any one of claims 1 to 8, wherein the monofunctional (meth)acrylic compound has a charge transport site.

10. The process cartridge according to claim 9, wherein the charge transport site has a triarylamine site.

11. The process cartridge according to claim 10, wherein the monofunctional (meth)acrylic compound is a compound represented by the following formula (A1) or (A2). 【Chemistry 1】 (In formula (A1), R １０１ ~R １１９ Each of these independently represents a hydrogen atom, a methyl group, or an ethyl group. m and n are each independently integers from 0 to 5. 【Chemistry 2】 (In formula (A2), R ２０１ ~R ２１９ Each of these independently represents a hydrogen atom, a methyl group, or an ethyl group. p and q are each independently integers between 0 and 5.

12. The surface layer contains a diphenylamine compound represented by the following formula (A3), The content of the diphenylamine compound in the surface layer is 0.001% by mass or more and 1.0% by mass or less, relative to the total mass of the surface layer. A process cartridge according to any one of claims 1 to 11. 【Transformation 3】 (In formula (A3), R ３０１ ~R ３１０ Each of these independently represents a hydrogen atom, a methyl group, or an ethyl group.

13. The process cartridge according to claim 12, wherein the content of the diphenylamine compound in the surface layer is 0.1% by mass or less with respect to the total mass of the surface layer.

14. The process cartridge according to any one of claims 1 to 13, wherein the surface layer contains particles A containing metal atoms.

15. The process cartridge according to claim 14, wherein the particle A is a metal oxide particle.

16. The process cartridge according to claim 15, wherein the metal oxide particles are alumina particles.

17. The process cartridge according to any one of claims 14 to 16, wherein the content ratio of the particles A in the surface layer is 4% by mass or more and 16% by mass or less with respect to the total mass of the surface layer.

18. An electrophotographic apparatus characterized by having a process cartridge according to any one of claims 1 to 17.

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