Electrophotographic member, process cartridge and electrophotographic image forming apparatus

Abstract

To provide an electrophotographic member that, even when subjected to formation of electronic images for a long period in a high-temperature and high-humidity environment, can achieve, at a higher level, both prevention of wear of a surface and prevention of deterioration of toner.SOLUTION: An electrophotographic member has a conductive substrate and a single-layer elastic layer on the substrate. The elastic layer contains silicone rubber having a dimethylsiloxane structure. When T1 is a peak top temperature of an ion thermogram derived from the dimethylsiloxane structure measured from a first sample that is sampled from a first area 41 having a thickness of 0.5 μm from a first surface toward a second surface of the elastic layer, and T2 is a peak top temperature of an ion thermogram derived from the dimethylsiloxane structure measured from a second sample that is sampled from a second area having a thickness of 1.0 μm to 1.5 μm from the second surface toward the first surface, the relationship of T1>T2 is satisfied.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to an electrophotographic member incorporated in an apparatus employing an electrophotographic system, and also to a process cartridge and an electrophotographic image forming apparatus using the electrophotographic member. [Background technology]

[0002] In an electrophotographic image forming apparatus, an image carrier is charged by a charging member, and an electrostatic latent image is formed by exposure light. Next, toner in a developer container is applied to a developing member by a toner supply member and a toner regulating member, and the electrostatic latent image formed on the image carrier is developed by the toner at the contact point between the image carrier and the developing member or in an area close to the contact point. The toner on the image carrier is then transferred to recording paper by a transfer means and fixed by heat and pressure. Furthermore, any toner remaining on the image carrier after transfer is removed by a cleaning blade. Electrophotographic members used in such electrophotographic image forming apparatuses, such as developing members, charging members, toner supply members, and toner regulating members, are required to maintain their initial performance even after long-term use, i.e., to have excellent durability. Furthermore, in response to the recent demand for lower power consumption, toners that can be fixed even at low temperatures are being used. Such toners are relatively susceptible to deterioration. Therefore, further suppression of toner deterioration is also required. Therefore, to further suppress toner degradation, flexible silicone rubber is sometimes used in electrophotographic materials to further reduce the stress on the toner. Silicone rubber has a helical structure in the siloxane bond of its main chain, and this helical structure unique to silicone rubber exhibits a variety of properties not found in organic polymers with a main chain consisting of C-C bonds. This gives it stable rubber elasticity over a wide temperature range compared to natural rubber and other synthetic rubbers, and it also has excellent heat and cold resistance. However, silicone rubber still has room for improvement in terms of abrasion resistance. Patent Document 1 discloses a silicone rubber elastic body in which a silane coupling agent is mixed into the silicone rubber to improve abrasion resistance, and a developing member using the same. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 4-76577 Summary of the Invention [Problem to be solved by the invention]

[0004] At least one aspect of the present disclosure is directed to providing an electrophotographic member that can suppress both surface wear and toner degradation at a higher level even when used to form electrophotographic images over a long period of time in a high-temperature, high-humidity environment. At least one aspect of the present disclosure is directed to providing a process cartridge that contributes to the stable formation of high-quality electrophotographic images. Furthermore, at least one aspect of the present disclosure is directed to providing an electrophotographic image forming apparatus that can stably form high-quality electrophotographic images. [Means for solving the problem]

[0005] According to at least one aspect of the present disclosure, 1. An electrophotographic member having an electrically conductive substrate and a single elastic layer on the substrate, comprising: the elastic layer contains a silicone rubber containing a dimethylsiloxane structure, When the side of the elastic layer facing the substrate is defined as a second surface and the surface of the elastic layer opposite to the second surface is defined as a first surface, From the first surface to the second surface of T1 (°C) is the peak top temperature of an ion thermogram derived from the dimethylsiloxane structure measured from a first sample sampled from a first region having a thickness of 0.5 μm toward the surface, when the peak top temperature of an ion thermogram derived from the dimethylsiloxane structure measured from a second sample sampled from a second region of the elastic layer having a thickness of 1.0 μm to 1.5 μm from the second surface toward the first surface is defined as T2 (°C), Applicable T1 and Applicable T2 、 The relationship shown in the following formula (1) is satisfied. death, Formula (1) T1 > T2 T1-T2 is in the range of 3.3℃~9.1℃, An electrophotographic member is provided, characterized in that .

[0006] Further, according to at least one aspect of the present disclosure, A process cartridge configured to be detachably mountable to a main body of an electrophotographic image forming apparatus, the process cartridge having the electrophotographic member described above. , characterized in that A process cartridge is provided. Further, according to at least one aspect of the present disclosure, an image carrier for carrying an electrostatic latent image; a charging device for primarily charging the image carrier; an exposure device for forming an electrostatic latent image on the image carrier that has been primarily charged; a developing member for developing the electrostatic latent image with toner to form a toner image; and a transfer device for transferring the toner image to a transfer material. In an electrophotographic image forming apparatus , The developing member 、 The electrophotographic member , characterized in that An electrophotographic imaging apparatus is provided. [Effects of the Invention]

[0007] According to at least one embodiment of the present disclosure, it is possible to obtain an electrophotographic member having an elastic layer containing silicone rubber, which is capable of suppressing both scraping due to wear and filming due to toner deterioration and has excellent durability. Furthermore, according to at least one aspect of the present disclosure, it is possible to obtain a process cartridge that contributes to the stable formation of high-quality electrophotographic images.Furthermore, according to at least one aspect of the present disclosure, it is possible to obtain an electrophotographic image forming apparatus that can stably form high-quality electrophotographic images. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a conceptual diagram illustrating an example of an electrophotographic member according to one embodiment of the present disclosure. [Figure 2] 1 is a schematic configuration diagram illustrating an example of a process cartridge according to an embodiment of the present disclosure. [Figure 3] 1 is a schematic configuration diagram illustrating an example of an electrophotographic image forming apparatus according to an embodiment of the present disclosure. [Figure 4] 1 is a schematic diagram illustrating an example cross section of an electrophotographic member according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present inventors have studied a developing roller using a silicone rubber material according to the invention described in Patent Document 1. As a result, the developing roller exhibited excellent abrasion resistance, but when used to form a large number of electrophotographic images in a high-temperature, high-humidity environment, filming due to deteriorated toner occurs on the outer surface (toner-carrying surface) of the developing roller, which can result in a deterioration in the quality of the electrophotographic images. The occurrence of filming on the outer surface of the developing roller is believed to be due to the increased hardness of the silicone rubber according to the invention described in Patent Document 1, caused by the action of the silane coupling agent. In other words, the inventors speculate that the increased hardness of the elastic layer containing silicone rubber caused the toner to receive more stress from the developing roller, accelerating toner degradation and resulting in the occurrence of filming on the outer surface of the developing roller. Therefore, the present inventors have conducted extensive research to obtain a developing roller with improved surface wear resistance while suppressing an increase in stress applied to the toner. As a result, they have found that reducing the molecular mobility of the silicone rubber in a region 0.5 μm deep from the outer surface of the elastic layer containing silicone rubber containing a dimethylsiloxane structure (hereinafter simply referred to as the "surface region") compared to the molecular mobility of the silicone rubber present in a region deeper than the surface region is effective in maintaining the flexibility of the elastic layer and improving the wear resistance of the outer surface. That is, an electrophotographic member according to at least one embodiment of the present disclosure includes a conductive substrate and a single-layer elastic layer on the substrate. The elastic layer contains a silicone rubber containing a dimethylsiloxane structure. When the side of the elastic layer facing the substrate is defined as a second surface and the surface of the elastic layer opposite the second surface is defined as a first surface, the peak-top temperature of an ion thermogram attributable to the dimethylsiloxane structure measured from a first sample sampled from a first region (surface region) 0.5 μm thick extending from the first surface toward the second surface is defined as T1 (°C), and the peak-top temperature of an ion thermogram attributable to the dimethylsiloxane structure measured from a second sample sampled from a second region of the elastic layer extending from the second surface toward the first surface, from 1.0 μm to 1.5 μm thick, T2 (°C) satisfies the relationship shown in the following formula (1): Equation (1) T1 > T2.

[0010] At least one embodiment of an electrophotographic member according to the present disclosure will now be described with reference to the drawings. FIG. 1 is a circumferential cross-sectional view of an electrophotographic member having a conductive substrate 2 and an elastic layer 1 on the outer peripheral surface of the substrate. The elastic layer 1 and the conductive substrate 2 are synonymous with the elastic layer 44 and conductive substrate 45 shown in FIG. 4 . The side of the elastic layer 44 facing the conductive substrate 45 is referred to as the second surface 47, and the surface of the elastic layer 44 opposite the second surface 47 is referred to as the first surface 46. In this disclosure, as shown in FIG. 4 , a first region 41 is defined as a region extending from the first surface 46 to the second surface 47 to a thickness of 0.5 μm. A second region 42 is defined as a region extending from the second surface 47 to the first surface 46 to a thickness of 1.0 μm to 1.5 μm. A third region 43 is defined as a region extending from the first surface 46 to the second surface 47 to a thickness of 10.0 μm to 10.5 μm.

[0011] An electrophotographic member according to at least one embodiment of the present disclosure has a conductive substrate 2 and a single-layer elastic layer 1 on the substrate. The elastic layer contains silicone rubber. Here, the peak-top temperature of an ion thermogram derived from a dimethylsiloxane structure measured from a first sample sampled from a first region 41 is defined as T1 (°C). Similarly, the peak-top temperature of an ion thermogram derived from a dimethylsiloxane structure measured from a second sample sampled from a second region 42 is defined as T2 (°C). In the elastic layer according to this embodiment, T1 and T2 satisfy the relationship shown in the following formula (1): Equation (1) T1 > T2. In the elastic layer satisfying the formula (1), T1-T2 is preferably in the range of 3.3°C to 9.1°C, and particularly preferably in the range of 3.3°C to 6.1°C. Furthermore, T1 is preferably in the range of 468.1°C to 470.8°C. The thickness of the elastic layer satisfying the formula (1) is not particularly limited, but from the viewpoint of achieving a high level of both easing stress on the toner and preventing wear of the outer surface, it is preferably 0.1 mm to 6.0 mm, particularly 0.3 mm to 6.0 mm, and even more preferably 1.0 mm to 6.0 mm.

[0012] The peak top temperature of the ion thermogram can be measured using, for example, an ion trap mass spectrometer (trade name: Polaris Q, manufactured by Thermo Fisher Scientific). First, the measurement area is cut into a thin slice using a microtome, and the measurement sample is then cut from the slice. The resulting measurement sample is attached to a filament at the tip of the Direct Exposure probe and inserted directly into the ionization chamber. It is then rapidly heated from room temperature to 700°C at a constant heating rate. The sample decomposes and vaporizes as a result of heating, and is then ionized by irradiation with an electron beam and detected by a mass spectrometer. Under constant heating conditions, a thermogram similar to that obtained by simultaneous thermogravimetry-mass analysis (TG-MS) is obtained, with a mass spectrum called a total ion thermogram (TIT). For example, by using data acquisition and analysis software (trade name: Xcalibur, manufactured by Thermo Fisher Scientific), materials can be identified from the obtained thermogram. Furthermore, an ion thermogram for a specific mass fragment can also be obtained, allowing the peak-top temperature of the ion thermogram, which corresponds to the decomposition temperature of the desired molecular structure, to be determined. A shift in the peak-top temperature of an ion thermogram for the same molecular structure toward a higher temperature indicates that the decomposition of that molecular structure no longer occurs at a higher temperature. This phenomenon is thought to be caused, for example, by a decrease in the molecular mobility of the polymer having that molecular structure. In the elastic layer according to the present disclosure, T1 > T2 means that the molecular mobility of the silicone rubber contained in the first region is lower than that of the silicone rubber contained in the second region, thereby obtaining an elastic layer with improved wear resistance on the outer surface while maintaining the flexibility of the silicone rubber.

[0013] Methods for reducing the molecular mobility of the silicone rubber contained in the first region to that of the silicone rubber contained in the second region include, for example, at least one method selected from the group consisting of a method for increasing the degree of cross-linking of the silicone rubber contained in the surface region and a method for surrounding the molecules of the silicone rubber contained in the surface region with another polymer. A method for obtaining an elastic layer in which the degree of cross-linking of the silicone rubber contained in the surface region is higher than the degree of cross-linking of the silicone rubber contained in a region deeper than the surface region includes, for example, irradiating an electron beam (EB) from the outer surface side of the silicone rubber-containing layer that is to become the elastic layer. Methods for obtaining an elastic layer in which the silicone rubber contained in the surface region is surrounded by another polymer include, for example, a method of impregnating the outer surface of the silicone rubber-containing layer that will become the elastic layer with a liquid containing the other polymer in a dissolved state, and a method of impregnating with a liquid containing the raw material of the other polymer (monomer, oligomer, prepolymer, etc.) and then curing the raw material. Hereinafter, these methods may also be referred to as "impregnation methods." As described above, one example of the impregnation method involves impregnating a region of the outer surface of the silicone rubber-containing layer with a monomer that serves as a raw material for another polymer, and then curing the monomer in the corresponding region. The resulting surface region of the elastic layer contains silicone rubber and a polymer different from the silicone rubber. Meanwhile, in at least a portion of the region deeper than the surface region of the elastic layer, the monomer is not impregnated even by the impregnation process, and therefore no polymer derived from the monomer is present. That is, an electrophotographic member according to an embodiment of the present disclosure obtained by the impregnation method satisfies the condition of the above formula (1), and the first sample contains a polymer that is not contained in the second sample. The peak top temperature of an ion thermogram derived from the polymer measured from the first sample is defined as C1 (°C). Furthermore, the peak top temperature of an ion thermogram derived from the polymer measured from a third sample obtained by decomposing the silicone rubber contained in the first sample is defined as C2 (°C). In an electrophotographic member according to an embodiment of the present disclosure, C1 and C2 preferably satisfy the relationship represented by the following formula (2): Equation (2) C1 > C2. In an elastic layer that satisfies formula (2) in addition to formula (1), C1 is preferably in the range of 414.2°C to 423.4°C, C1-C2 is preferably in the range of 0.9°C to 3.6°C, T1 is preferably in the range of 468.1°C to 470.8°C, and T1-T2 is preferably in the range of 3.3°C to 9.1°C, particularly preferably in the range of 3.3°C to 6.1°C. The thickness of the elastic layer satisfying the formulas (1) and (2) is not particularly limited, but from the viewpoint of achieving a high level of both easing stress on the toner and preventing wear of the outer surface, it is preferably 0.1 mm to 6.0 mm, particularly 0.3 mm to 6.0 mm, and further preferably 1.0 mm to 6.0 mm.

[0014] Methods for decomposing silicone rubber include the tetraethoxysilane (TEOS) method, alkali fusion method, fluorosilanization method, and methyl orthoformate (MOF) decomposition method, which selectively decompose the siloxane bonds contained in silicone rubber. By using these methods to remove the dimethylsiloxane structures derived from silicone rubber, a third sample containing the polymer from which the dimethylsiloxane structures have been removed can be obtained. The peak-top temperature of the ion thermogram derived from the polymer correlates with the degree of cross-linking of the polymer. Therefore, the fact that C1 before silicone rubber removal is higher than C2 after silicone rubber removal indicates a higher degree of cross-linking, i.e., higher hardness, before removal of the dimethylsiloxane structure than after removal. Therefore, when the relationships shown in the above formulas (1) and (2) are satisfied, it is believed that the polymer penetrates into the network structure and helical structure between the silicone polymers that make up the elastic layer. As a result, it is suggested that the network structures of the silicone rubber and the polymer are intertwined and entangled with each other without being linked by covalent bonds, forming an interpenetrating polymer network structure. Hereinafter, this interpenetrating polymer network structure will be referred to as an "IPN structure." An interpenetrating polymer network (IPN) is defined as a structure in which the network structures of two or more polymer compounds are intertwined and entangled without being linked by covalent bonds. Because the materials that make up the IPN structure are not chemically bonded to each other, the properties of each material are not impaired, while the entanglement of the materials is expected to improve strength.

[0015] The IPN structure in the elastic layer according to this embodiment is formed by the polymer penetrating into the three-dimensionally crosslinked network of the silicone rubber. The IPN structure will not unravel unless the molecular chains of the polymer compound forming the network are cut. Several methods can be used to form the IPN structure. For example, a method known as a sequential network formation method is used, in which a network of the first component polymer is first formed, then swollen with a second component monomer and, if necessary, a polymerization initiator, and then a network of the second component polymer is formed. Alternatively, a simultaneous network formation method is used, in which a first component monomer, a second component monomer, and their respective polymerization initiators, each having a different reaction mechanism, are mixed and polymerized simultaneously to form a network structure. The first component, silicone rubber, and the second component, polymer, which form the IPN structure, do not have a covalent bond, so rubber elasticity is not lost, while the entanglement of the silicone rubber and the second component, polymer, is expected to improve strength. Furthermore, the combination of the helical structure unique to silicone rubber and the properties of the IPN structure is thought to produce a synergistic effect. That is, the elastic layer maintains the flexibility of silicone rubber inside, while the formation of an IPN structure increases the hardness of only the very outermost surface. As a result, the elastic layer is thought to be able to achieve both further improvement in abrasion resistance and reduction in stress on the toner. Furthermore, to form an IPN structure, it is preferable to use a silicone rubber whose main component is a silicone polymer with a more uniform molecular weight. When forming an IPN structure in such a silicone rubber, the second component monomer is more likely to penetrate uniformly, and the second component monomer is more likely to penetrate into the network structure of the silicone rubber than when forming an IPN structure in a silicone rubber with a non-uniform molecular weight. As a result, the molecular motion of the silicone rubber can be uniformly restricted, thereby suppressing abrasion and filming to a higher level.

[0016] The polymer of the second component is preferably an acrylic resin, an epoxy resin, a urethane resin, etc. Polymer materials such as acrylic resin, epoxy resin, and urethane resin usually have high strength, but may be hard and brittle when used alone. Therefore, when used as a single film on the surface layer of an electrophotographic member, its brittleness makes it prone to wear and chipping due to friction. Furthermore, its high hardness can easily increase the load on the toner, which can lead to toner degradation and filming. On the other hand, when incorporated as an IPN structure with a helical silicone rubber, its crystallinity is disrupted, making it less likely to exhibit hardness and brittleness. Each resin material and its impregnation method will be explained below. The treatment liquid for impregnation containing the monomer component of each resin is called the impregnation treatment liquid.

[0017] (1) Acrylic resin Examples of acrylic resins include resins containing structural units derived from (meth)acryloyl groups, such as those represented by structural formula (I).

[0018] [ka] In structural formula (I), A represents a hydrogen atom or a methyl group, and G represents -OR1 or -NR 2 R 3 Indicates R 1 , R 2 , R 3 each independently represents a hydrogen atom or an organic group, and R 2 and R 3 may be linked to form a ring.

[0019] The presence of structural formula (I) can be determined by detecting whether or not a compound derived from a (meth)acryloyl group is detected by a general mass spectrometry method such as pyrolysis GC / MS. Acrylic resins are formed by the polymerization of either acrylic monomers or methacrylic monomers, or both. In this specification, "acrylic" and "methacrylic" may be collectively referred to as "(meth)acrylic." Similarly, "acryloyl" and "methacryloyl" may be collectively referred to as "(meth)acryloyl." The acrylic monomer is preferably a polyfunctional monomer having multiple acryloyl or methacryloyl groups as functional groups in order to form a crosslinked structure. On the other hand, if the functional groups are four or more, the viscosity of the acrylic monomer increases significantly, making it difficult for the acrylic monomer to penetrate into the surface of the elastic layer containing silicone rubber, and as a result, it is difficult to form an IPN structure. Therefore, the acrylic monomer is preferably a monomer having two or three acryloyl and methacryloyl groups in one molecule, and more preferably a bifunctional acrylic monomer having two acryloyl and methacryloyl groups in one molecule.

[0020] The molecular weight of the acrylic monomer is preferably in the range of 200 to 750. By using an acrylic monomer with a molecular weight in this range, an IPN structure can be easily formed with respect to the network structure of the silicone rubber, and the strength of the elastic layer can be effectively improved. As described above, in the manufacturing process for the electrophotographic member according to the present disclosure, the acrylic monomer is impregnated into the elastic layer containing the silicone rubber. To this end, the acrylic monomer preferably has a viscosity sufficient to allow the acrylic monomer to be impregnated into the silicone rubber. Specifically, for example, the viscosity of the impregnation treatment solution containing the acrylic monomer is preferably 5.0 mPa·s or more and 140 mPa·s or less at a temperature of 25°C. The solvent can be freely selected as long as it has both affinity with the elastic layer and solubility for the acrylic monomer, such as alcohols such as methanol, ethanol, and n-propanol, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, and esters such as methyl acetate and ethyl acetate. An IPN structure of silicone rubber and acrylic resin can be formed by impregnating an elastic layer with an impregnation treatment solution containing one or more selected acrylic monomers that satisfy the above-mentioned molecular weight and viscosity ranges and polymerizing the solution.

[0021] The method for polymerizing the acrylic monomer is not particularly limited, and known methods can be used, such as thermal polymerization by heating and photopolymerization by ultraviolet irradiation. For each polymerization method, a known radical polymerization initiator or ionic polymerization initiator can be used, and therefore, the impregnation treatment solution used contains the above acrylic monomer and these polymerization initiators. Examples of the thermal polymerization initiator for thermal polymerization include peroxides such as 3-hydroxy-1,1-dimethylbutylperoxyneodecanoate, α-cumylperoxyneodecanoate, t-butylperoxyneoheptanoate, t-butylperoxypivalate, t-amylperoxynormaloctoate, t-butylperoxy2-ethylhexylcarbonate, dicumyl peroxide, di-t-butyl peroxide, di-t-amyl peroxide, 1,1-di(t-butylperoxy)cyclohexane, and n-butyl-4,4-di(t-butylperoxy)valerate; Examples of azo compounds include 2,2-azobisbutyronitrile, 2,2-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-methylbutyronitrile), 1,1-azobis(cyclohexane-1-carbonitrile), 2,2-azobis[2-(2-imidazolin-2-yl)propane], 2,2-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 2,2-azobis[N-(2-propenyl)-2-methylpropionamide], 2,2-azobis(N-butyl-2-methoxypropionamide), and dimethyl-2,2-azobis(isobutyrate).

[0022] Examples of photopolymerization initiators for photopolymerization by irradiation with ultraviolet light include 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methylpropane. -1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide are examples thereof. These polymerization initiators may be used alone or in combination of two or more. Furthermore, the amount of the polymerization initiator to be used is preferably 0.5 parts by mass or more and 10 parts by mass or less, from the viewpoint of efficiently progressing the reaction, when the total amount of the compounds for forming the specific resin (for example, compounds having a (meth)acryloyl group) is taken as 100 parts by mass. Known heating devices and UV irradiation devices can be used as appropriate. Examples of UV irradiation light sources that can be used include LED lamps, high-pressure mercury lamps, metal halide lamps, xenon lamps, and low-pressure mercury lamps. The cumulative light intensity required for polymerization can be adjusted as appropriate depending on the types and amounts of compounds and polymerization initiators used.

[0023] (2) Epoxy resin The epoxy resin may be, for example, a resin having a group derived from an epoxy group, as represented by structural formula (II).

[0024] [ka]

[0025] The presence of structural formula (II) can be determined by detecting or not detecting compounds derived from epoxy groups using a general mass spectrometry method such as pyrolysis GC / MS. The epoxy resin is preferably a polymer formed by ring-opening addition polymerization of glycidyl groups, as shown in the following structural formula (III): where R is a divalent organic group, and is particularly preferably an alkylene group.

[0026] [ka]

[0027] Examples of monomers that provide the polymer represented by structural formula (III) include bifunctional glycidyl ether monomers having the R structure in structural formula (III) in the main chain, as represented by structural formula (IV) below.

[0028] [ka]

[0029] The glycidyl ether monomer of structural formula (IV) is preferably an alkyl glycidyl ether, such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,5-pentanediol glycidyl ether, neopentyl glycol diglycidyl ether, or 1,6-hexanediol diglycidyl ether.

[0030] As the glycidyl ether monomer, a low-molecular-weight glycidyl ether is preferred from the viewpoint of ease of impregnation into the elastic layer. Also, from the same viewpoint, since the lower the viscosity of the monomer, the easier it is to impregnate, an aliphatic glycidyl ether monomer that does not have a rigid structure in the main chain and has low viscosity is preferred. The specific examples of the alkyl glycidyl ether monomers mentioned above satisfy these conditions. The solvent can be freely selected as long as it has both affinity with the elastic layer and the solubility of the glycidyl ether monomer. Examples include alcohols such as methanol, ethanol, and n-propanol, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, and esters such as methyl acetate and ethyl acetate. A polymerization initiator can also be mixed into the impregnation treatment solution. Details of the polymerization initiator will be described later. An IPN structure of silicone rubber and epoxy resin can be formed by impregnating the elastic layer with an impregnation treatment liquid containing one or more selected types of the above-mentioned glycidyl ether monomers and polymerizing the liquid. The polymerization method is not particularly limited, and known methods can be used. Specific examples include heat curing and ultraviolet irradiation. In particular, the method of curing a glycidyl ether monomer by ultraviolet irradiation is more preferred because excessive heat is applied to the glycidyl ether monomer, allowing it to be efficiently polymerized and cured within the system without volatilizing outside the system.

[0031] For each polymerization method, a polymerization initiator such as a known radical polymerization initiator or ionic polymerization initiator can be used. Specific examples include the same initiators as those used for acrylic resins, but cationic polymerization initiators mainly composed of aromatic sulfonium salts are preferred. These polymerization initiators may be used alone or in combination of two or more. Furthermore, the amount of the polymerization initiator to be used is preferably 0.5 parts by mass or more and 10 parts by mass or less, from the viewpoint of efficiently progressing the reaction, when the total amount of compounds for forming the specific resin (e.g., compounds having a glycidyl group) is taken as 100 parts by mass. Known heating devices and UV irradiation devices can be used as appropriate. Examples of UV irradiation light sources include LED lamps, high-pressure mercury lamps, metal halide lamps, xenon lamps, and low-pressure mercury lamps. The cumulative light intensity required for polymerization can be adjusted as appropriate depending on the types and amounts of compounds and polymerization initiators used.

[0032] (3) Urethane resin The urethane resin may be, for example, a resin having a urethane bond represented by structural formula (V).

[0033] [ka]

[0034] The presence of urethane bonds can be determined by detecting compounds derived from urethane bonds using a general mass spectrometry method such as pyrolysis GC / MS. The urethane resin is produced by the reaction of an isocyanate compound with a substance having a hydrogen group. Examples of the isocyanate compound include 2,6-tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), paraphenylene diisocyanate (PPDI), 1,5-naphthalene diisocyanate (NDI), and 3,3-dimethyldiphenyl-4,4'-diisocyanate (TODI), as well as the above-mentioned polymers and modified products. Examples of substances having a hydrogen group include compounds having a hydroxyl group such as polyols, and moisture in the atmosphere. The solvent can be freely selected as long as it has both affinity with the resin layer and solubility for the isocyanate compound, and examples thereof include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, and esters such as methyl acetate and ethyl acetate. An IPN structure of silicone rubber and urethane resin can be formed by impregnating the elastic layer with an impregnation treatment liquid containing one or more selected isocyanate compounds as described above and heating the liquid to cause a reaction.

[0035] As shown in FIG. 4 , when a fourth sample is sampled from a third region 43 having a thickness of 10.0 μm to 10.5 μm from a first surface 46 toward a second surface 47, T1, T2, and T3 of the elastic layer according to the present disclosure can be expressed by the following formulas (3) and (4), where T3 (° C.) is the peak top temperature of an ion thermogram derived from a dimethylsiloxane structure measured from the fourth sample. Equation (3) T1 > T3 ≧ T2 Formula (4) T1 > T3 + 1.0(℃) It is preferable that the following relationship is satisfied. That is, it is preferable that the first region has a higher hardness than the third region, and the third region has a hardness equal to or higher than that of the second region. To further reduce the stress on the toner caused by the developing roller, it is preferable that the thickness of the high-hardness region of the elastic layer be small. To achieve this, the peak-top temperature difference (T1-T3) between the first and third regions is preferably 1.0°C or greater. That is, the thickness of the high-hardness region from the outer surface to the depth of the elastic layer can be estimated from the peak-top temperature difference (T1-T3) between the first and third regions. In an elastic layer formed by impregnation and satisfying the relationship of formula (1), when T1-T3=0°C, it is considered that the impregnation of other polymers from the outer surface reaches the third region. This means that the high-hardness region extends from the first surface of the elastic layer to the third region at a depth of 10.5 μm. On the other hand, the larger T1-T3, the more likely it is that the impregnation of the polymer is limited to the vicinity of the outer surface. To further reduce the stress on the toner, it is preferable that the high-hardness region is formed only in the vicinity of the outer surface. Therefore, T1-T3 is preferably 0.3°C to 5.9°C, particularly 0.8°C to 5.9°C, and further preferably 1.3°C to 5.9°C. Furthermore, in an elastic layer satisfying the relationships of formulas (1) to (4), T1 is preferably in the range of 468.1°C to 470.8°C, and T1-T2 is preferably in the range of 3.3°C to 9.1°C, and particularly preferably in the range of 3.3°C to 6.1°C. Furthermore, in an elastic layer satisfying formula (2) in addition to formulas (3) and (4), C1 is preferably in the range of 414.2°C to 423.4°C, and C1-C2 is preferably in the range of 0.9°C to 3.6°C. The thickness of the elastic layer that satisfies the relationships of formulas (1) to (4) is not particularly limited, but from the viewpoint of achieving a higher level of both easing stress on the toner and preventing wear of the outer surface, it is preferably 0.1 mm to 6.0 mm, particularly 0.3 mm to 6.0 mm, and even more preferably 1.0 mm to 6.0 mm.

[0036] [Conductive substrate] A columnar or cylindrical conductive mandrel can be used as the conductive base 2. A conductive elastic layer may be provided on the outer periphery of the mandrel, in which case the conductive elastic layer and the mandrel are considered to be the conductive base. The conductive mandrel has a conductive outer surface, and the surface of the substrate may be subjected to a known surface treatment or may be provided with an adhesive layer in order to improve adhesion to the elastic layer provided on the outer periphery of the substrate. The conductive mandrel may be made of the following conductive materials: Metals or alloys such as aluminum, copper alloys, stainless steel; Chromium- or nickel-plated iron; A synthetic resin with electrical conductivity.

[0037] [Elastic layer] The elastic layer 1 is a single elastic layer that constitutes the outer surface of the electrophotographic member. Silicone rubber is selected as the material for the elastic layer because silicone rubber is a rubber material used in electrophotographic members that is unlikely to cause compression set in the conductive elastic layer even when it comes into contact with other members over a long period of time. As mentioned above, the thickness of the elastic layer is not particularly limited, but from the viewpoint of achieving a higher level of both easing stress on the toner and preventing wear of the outer surface, it is preferable that the thickness be 0.1 mm to 6.0 mm, particularly 0.3 mm to 6.0 mm, and even more preferably 1.0 mm to 6.0 mm. Silicone rubber is classified into two types based on its form. One type is called millable silicone rubber, which uses a high degree of polymerization linear polyorganosiloxane and blends it with reinforcing fillers such as silica to prepare a rubber compound, which is then heated and cured by adding a crosslinking agent. The other type is liquid silicone rubber, which uses organopolysiloxane with a lower degree of polymerization than the millable type. Liquid silicone rubber is further divided into types that cure indoors and types that cure by heating. The silicone polymer, the main component of silicone rubber, is mainly a polymer with a degree of polymerization of approximately 4,000 to 10,000 for millable silicone rubber and approximately 100 to 2,000 for liquid silicone rubber.

[0038] The elastic layer can be made conductive by compounding the rubber material with a conductivity imparting agent such as an electronically conductive substance or an ionic conductive substance. Examples of electronically conductive materials include the following: conductive carbon black, such as conductive carbon, carbon for rubber, and carbon for color (ink), and metals and their metal oxides. Examples include highly conductive carbon, such as Ketjenblack EC and acetylene black; carbon for rubber, such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT; carbon for color (ink) obtained by oxidizing carbon black powder; and metals and their metal oxides, such as copper, silver, and germanium. Among these, conductive carbon black (conductive carbon, carbon for rubber, and carbon for color (ink)) is preferred because it is easy to control conductivity with a small amount. Examples of ion-conductive substances include the following: inorganic ion-conductive substances such as sodium perchlorate, lithium perchlorate, calcium perchlorate, and lithium chloride; and organic ion-conductive substances such as modified aliphatic dimethylammonium ethosulfate and stearylammonium acetate. The elastic layer may further contain various additives such as plasticizers, fillers, extenders, vulcanizing agents, vulcanization aids, crosslinking aids, cure inhibitors, antioxidants, antioxidants, and processing aids, as needed. Examples of fillers include silica, quartz powder, and calcium carbonate. These optional components are blended in amounts that do not impair the function of the elastic layer.

[0039] <Formation method> The method for forming the elastic layer on the outer periphery of the conductive substrate is not particularly limited, and examples thereof include molding, extrusion, injection, and coating. In molding, for example, first, pieces for holding a mandrel in the mold are fixed to both ends of a cylindrical mold, and an injection port is formed in the pieces. Next, a mandrel is placed in the mold, and a material for the elastic layer is injected through the injection port. The mold is then heated to a temperature at which the material hardens, and the mold is demolded. In extrusion, for example, a crosshead extruder is used to extrude the mandrel and the material for the elastic layer together, and the material is hardened to form a silicone rubber layer, which will be the main component of the elastic layer, around the mandrel. When the electrophotographic member is a roller member, a polishing step may be carried out after forming the silicone rubber layer on the substrate to process it into a crown shape. The crown shape is formed by polishing the silicone rubber layer more at both longitudinal ends of the substrate (mandrel) so that the thickness of the silicone rubber layer in the center is thicker. Furthermore, the polished silicone rubber layer may be pretreated by a surface modification method such as corona treatment, flame treatment, or excimer treatment. By pretreating, the impregnation property in the subsequent impregnation treatment can be adjusted to a desired range. Thereafter, EB exposure and impregnation treatment are performed to harden the surface region of the elastic layer. As described for the acrylic monomer, the impregnation treatment liquid is diluted with a solvent or the like to have an appropriate viscosity before use. The impregnation method for the impregnation treatment liquid is not particularly limited, and dip coating, ring coating, spray coating, or roll coating can be used. After the impregnation process, UV irradiation and heat curing processes are carried out to react the polymers of each second component. In the case of roller members, UV irradiation while rotating the roller member can ensure a uniform degree of cross-linking across the surface area.

[0040] <Catalytic compound> The catalyst compound is a catalyst used to promote the addition curing reaction between silicone polymers. Examples of the catalyst compound include the following: Examples of suitable materials include platinum fine powder, platinum black, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complexes of chloroplatinic acid, and complexes of platinum and alkenylsiloxane. Commercially available catalyst compounds can be used, and specific examples include SIP-6829.2, SIP-6832.2, SIP-6830.3, SIP-6831.2, and SIP-6833.2 (trade names, all manufactured by Gelest). These may be used alone or in combination of two or more. The content of the catalyst compound in the siloxane composition is preferably 1 ppm by mass or more and 100 ppm by mass or less from the viewpoint of curing reactivity.

[0041] <Other ingredients> In addition to the above catalyst compound, various additives such as a reinforcing agent, a cure regulator, a conductive agent, a plasticizer, a vulcanizing agent, a vulcanization aid, a crosslinking aid, an antioxidant, an antiaging agent, and a processing aid may be contained as needed, provided that the functions of the above composition are not impaired.

[0042] [Electrophotographic process cartridge and electrophotographic image forming apparatus] The electrophotographic image forming apparatus according to this embodiment has, for example, the following configuration. · an image carrier for carrying an electrostatic latent image; a charging device for primarily charging the image carrier; an exposure device for forming an electrostatic latent image on the image carrier that has been primarily charged; a developing device for developing the electrostatic latent image with toner to form a toner image; and A transfer device for transferring the toner image onto a transfer material. FIG. 3 is a cross-sectional view showing an outline of the electrophotographic image forming apparatus according to this embodiment. Fig. 2 is an enlarged cross-sectional view of a process cartridge to be mounted in the electrophotographic image forming apparatus of Fig. 3. This process cartridge incorporates an image carrier 21 such as a photosensitive drum, a charging device having a charging member 22, a developing device 20 having a developing member 24 and a toner supply member 25 and containing toner 201, and a cleaning device having a cleaning member 30. The process cartridge is configured to be detachably mountable to the main body of the electrophotographic image forming apparatus of Fig. 3. The image carrier 21 is uniformly charged (primary charging) by a charging member 22 connected to a bias power supply (not shown). At this time, the charged potential of the image carrier 21 is between -800V and -400V. Next, the image carrier 21 is irradiated with exposure light 23 for writing an electrostatic latent image by an exposure device (not shown), and an electrostatic latent image is formed on its surface. Either LED light or laser light can be used as the exposure light 23. The surface potential of the exposed portion of the image carrier 21 is between -200V and -100V. Next, negatively charged toner is applied (developed) to the electrostatic latent image by the developing member 24, forming a toner image on the image carrier 21 and converting the electrostatic latent image into a visible image. At this time, a voltage of -500 V or more and -300 V or less is applied to the developing member 24 by a bias power supply (not shown). The developing member 24 contacts the image carrier 21 with a nip width of 0.5 mm or more and 3 mm or less. In the process cartridge of this embodiment, a toner supply member 25 is rotatably contacted with the developing member 24 on the upstream side of the rotation of the developing member 24 with respect to the contact portion between the developing member 24 and a toner regulating blade 26, which is a toner regulating member. The toner image developed on the image carrier 21 is primarily transferred to the intermediate transfer belt 27. A primary transfer member 28 is in contact with the rear surface of the intermediate transfer belt 27, and a voltage of +100 V or more and +1500 V or less is applied to the primary transfer member 28 to primarily transfer the negative polarity toner image from the image carrier 21 to the intermediate transfer belt 27. The primary transfer member 28 may be in the form of a roller or a blade.

[0043] When the electrophotographic image forming apparatus is a full-color image forming apparatus, the above-mentioned charging, exposure, development, and primary transfer processes are performed for each of the colors yellow, cyan, magenta, and black. To this end, the electrophotographic image forming apparatus shown in FIG. 3 has four process cartridges, one for each color, detachably mounted in the main body of the electrophotographic image forming apparatus. The above-mentioned charging, exposure, development, and primary transfer processes are performed sequentially with a predetermined time difference, and a state in which four color toner images are superimposed on the intermediate transfer belt 27 to represent a full-color image is created. As the intermediate transfer belt 27 rotates, the toner image on the intermediate transfer belt 27 is transported to a position facing a secondary transfer member 29. Recording paper is transported between the intermediate transfer belt 27 and the secondary transfer member 29 along a recording paper transport route 32 at a predetermined timing, and the toner image on the intermediate transfer belt 27 is transferred to the recording paper by applying a secondary transfer bias to the secondary transfer member 29. At this time, the bias voltage applied to the secondary transfer member 29 is +1000 V or more and +4000 V or less. The recording paper onto which the toner image has been transferred by the secondary transfer member 29 is transported to a fixing device 31 along the recording paper transport route 32. The toner image on the recording paper is melted and fixed on the recording paper by the fixing device 31, and the recording paper is then ejected from the electrophotographic image forming apparatus, completing the printing operation. In addition, toner remaining on the image carrier 21 without being transferred from the image carrier 21 to the intermediate transfer belt 27 is scraped off by a cleaning member 30 for cleaning the surface of the image carrier 21, and the surface of the image carrier 21 is cleaned. [Example]

[0044] The present disclosure will be described in more detail below by giving specific examples using a developing roller as an example, but the technical scope of the present disclosure as an electrophotographic member is not limited thereto.

[0045] Example 1 [Production of polished rollers] A silicone primer (product name: Primer No. 16, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the surface of a SUS304 core bar having an outer diameter of 6 mm and a length of 264 mm, and the core was heated at a temperature of 150°C for 20 minutes to prepare a conductive substrate. Next, to form the elastic layer, the materials in Table 1 below were mixed and kneaded in a pressure kneader to prepare an addition-curable millable conductive silicone rubber composition.

[0046] [Table 1]

[0047] The prepared conductive substrate and addition-curable millable conductive silicone rubber composition were then extruded as a single unit using a crosshead extruder, and cured by heating in a gear oven at 250°C for 20 minutes. After that, the mixture was further heated in a gear oven at 200°C for 4 hours for secondary curing, and then left at room temperature for 24 hours. Next, the elastic layer formed on the outer periphery of the conductive substrate was ground using a cylindrical grinder to an outer diameter of 10 mm and a crown amount of 20 μm, resulting in a ground roller. The crown amount is the difference between the outer diameter at a position 10 mm from the end of the elastic layer and the outer diameter at the center of the elastic layer. The outer diameter of the elastic layer at the end was ground to 10.000 mm and the outer diameter at the center to 10.020 mm, so that the finished crown amount would be 20 μm. The outer diameter was measured at 10 mm intervals in the longitudinal direction using a laser length measuring device (product name: CONT MEMBER LS-7000, sensor head LS-7030R, manufactured by KEYENCE Corporation). The surface roughness of the polished roller was measured using a contact roughness meter (SURFCORD SE3500, manufactured by Kosaka Laboratory Co., Ltd.) and found to be Ra = 1.05 μm. [Preprocessing] Next, as a pretreatment, the polished roller was subjected to the following treatment. The ultraviolet lamp used was an excimer UV lamp (product name: GEL40XTS, manufactured by Harrison Toshiba Lighting Co., Ltd.), and the illuminance of 172 nm wavelength light at a position on the surface of the polished roller was measured with an ultraviolet integrating actinometer (main body: UIT-250, light receiving part: VUV-S172, both manufactured by Ushio Inc.). During this time, the distance was adjusted so that the illuminance was 15 mW. Irradiation was carried out for an integrated time of 13 seconds so that the integrated light amount was 200 mJ, to obtain a pretreated roller. [Impregnation treatment] Next, an impregnation treatment was carried out. The materials shown in Table 2 below were dissolved and mixed to form the impregnation treatment liquid for the impregnation treatment. The pretreated roller was immersed in this impregnation treatment liquid for 5 seconds to be impregnated with the impregnation treatment liquid. It was then air-dried at room temperature for 30 minutes, and then further dried at 90°C for 1 hour to volatilize the solvent.

[0048]

Table 2

[0049] Next, in order to react the impregnation treatment liquid, while rotating the dried roller, ultraviolet irradiation was performed with an ultraviolet lamp. The roller is rotatable during the ultraviolet treatment by a rotation mechanism. The rotation speed of the roller was set to 20 rpm, and while rotating, ultraviolet irradiation was performed for treatment. A filter, a glass plate for preventing contamination of the lamp, etc. may be appropriately arranged between the ultraviolet lamp and the roller. As the ultraviolet lamp used, a high-pressure mercury lamp (manufactured by Eye Graphics Co., Ltd.) was used. The illuminance at a wavelength of 365 nm at the position of the roller surface was measured with an ultraviolet integrated light meter (main body: UIT-250, light receiving part: UVD-S365, both manufactured byUSHIO ELECTRIC INC.), and the output and distance of the lamp were adjusted so that the illuminance became 100 mW. In this state, by irradiating ultraviolet rays for 200 seconds so that the integrated light amount becomes about 15000 mJ / cm 2 the acrylic monomer was cured to obtain a developing roller.

[0050] The following evaluations were performed on the obtained developing roller. [Evaluation method] <Measurement of T1, T2, T3, C1, and C2> First, the region of the developing roller to be measured was cut into a thin section using a microtome to prepare a sample. In this embodiment, as shown in FIG. 4, samples were prepared from three regions designated as a first region 41, a second region 42, and a third region 43. The first region 41 is a region of the elastic layer 44 with a thickness of 0.5 μm extending from the first surface to the second surface, and the second region 42 is a region of 1.0 μm to 1.5 μm extending from the second surface to the first surface. The third region 43 is a region of 10.0 μm to 10.5 μm extending from the first surface to the second surface. A first sample was collected from the first region, a second sample from the second region, and a fourth sample from the third region, and total ion thermograms were obtained for each. The total ion thermograms were measured using the above-mentioned ion trap mass spectrometer (trade name: Polaris Q, manufactured by Thermo Electron). From the obtained total ion thermograms, the peak-top temperatures T1, T2, and T3 of the ion thermograms derived from the dimethylsiloxane structure in the first, second, and third regions were determined. Furthermore, the peak-top temperature C1 of the ion thermogram derived from the acrylic resin was determined from the total ion thermogram of the first sample. Furthermore, the peak-top temperature C2 of the ion thermogram derived from the acrylic resin was determined from the total ion thermogram of a third sample obtained by removing the silicone rubber contained in the first sample using a silicone rubber decomposition method, as described below. Here, each peak-top temperature T1, T2, T3, C1, and C2 was the average value of measurements taken on 30 samples cut out from 10 samples cut out from the center of the developing roller and 10 samples cut out from both ends. The samples from each region were cut into thin sections using a microtome (trade name: Ultramicrotome, manufactured by Leica Microsystems). Specifically, a razor was used to make an incision from the surface of the developing roller toward the substrate, and a semi-cylindrical rubber piece was cut out, exposing the cross section of the elastic layer. The rubber piece was placed in the microtome sample holder with the first surface (outer surface) facing up. The first sample was obtained by scraping off the first region with a diamond knife, and the fourth sample was obtained by scraping off the third region with a diamond knife. The second sample was collected by placing the rubber piece on a sample holder of a microtome with the second surface of the elastic layer facing upward, and scraping it off from the second region with a diamond knife.

[0051] <How to decompose silicone rubber> A silicone resin dissolving agent (trade name: e-Solv 21RS, manufactured by Kaneko Chemical Co., Ltd.) was used to selectively decompose the siloxane bonds contained in the silicone rubber. Using a microtome, the first sample collected as described above was immersed in a silicone resin dissolving agent to dissolve the silicone rubber, and then filtered to obtain a third sample from which the dimethylsiloxane structure derived from the silicone rubber had been removed.

[0052] <Durability evaluation> The developing roller was mounted in a process cartridge for a color laser printer, and the state of abrasion and filming due to wear on the developing roller surface was evaluated using a color laser printer (product name: Color Laser Jet Pro M452dw, manufactured by Hewlett-Packard). The evaluation results are shown in Table 4 below. The evaluation procedure was as follows: The process cartridge was left for 16 hours in a high-temperature, high-humidity environment at a temperature of 30°C and a relative humidity of 95% for aging, and then, under the same environment, low-print images with a print rate of 0.2% were continuously output onto recording paper. This printing operation was continued until the cartridge replacement lamp on the laser printer came on. After the lamp came on, an additional 500 sheets were printed, and then the developing roller was removed from the process cartridge, and the roller surface was air-blowed to remove the toner coated on the surface. The developing roller after the endurance test was evaluated according to the following evaluation criteria.

[0053] <Evaluation criteria> After the durability test, the contact positions of the blade ends at both ends of the developing roller were measured using a laser length measuring device (product name: Conto LS-7000, sensor head LS-7030R, manufactured by KEYENCE Corporation) used to measure the outer diameter, and the state of abrasion was evaluated according to the following evaluation criteria. Rank "A": The change in roller outer diameter after endurance testing is 10 μm or less compared to the roller outer diameter before endurance testing. Rank "B": The change in roller outer diameter after endurance testing is between more than 10 μm and 30 μm or less compared to the roller outer diameter before endurance testing. Rank "C": The change in roller outer diameter after endurance testing is more than 30 μm compared to the roller outer diameter before endurance testing, or measurement is impossible due to abrasion.

[0054] In addition, the surface of the developing roller after the durability test was observed under a laser microscope (product name: VK-8700, manufactured by Keyence Corporation) using a 20x objective lens. The toner-coated portion was divided into three parts along the axial direction of the roller, and three points were observed in each circumferential direction, for a total of nine points for each sample. The area of ​​adhered toner was determined at each of the nine points, and the average of the nine values ​​was taken as the state of filming and evaluated according to the following evaluation criteria. Rank "A": The area of ​​adhered toner relative to the roller surface area is 5% or less. Rank "B": The area of ​​adhered toner relative to the roller surface area is more than 5% to 15% or less. Rank "C": The area of ​​adhered toner is more than 15% of the roller surface area. The evaluation results are shown in Table 4.

[0055] Example 2 A developing roller was produced in the same manner as in Example 1, except that the ultraviolet ray irradiation time was changed to 100 seconds, and was evaluated in the same manner as in Example 1.

[0056] Example 3 A developing roller was produced in the same manner as in Example 2, except that an impregnation treatment liquid for introducing an IPN structure using an epoxy resin was used in the impregnation treatment. The impregnation treatment liquid was a solution mixture of 5 parts by mass of a glycidyl ether monomer (trade name: ethylene glycol diglycidyl ether, manufactured by Tokyo Chemical Industry Co., Ltd.), 0.1 parts by mass of a photopolymerization initiator (trade name: San-Aid SI-100L, manufactured by Sanshin Chemical Industry Co., Ltd.), and 100 parts by mass of a solvent (methyl ethyl ketone). The resulting developing roller was evaluated in the same manner as in Example 1.

[0057] Example 4 A developing roller was produced in the same manner as in Example 2, except that in the impregnation treatment, an impregnation treatment liquid for introducing an IPN structure using a urethane resin was used. The impregnation treatment liquid was a mixture of 14.3 parts by mass of an isocyanate compound (trade name: Millionate MR-400, manufactured by Tosoh Corporation) and 100 parts by mass of a solvent (ethyl acetate). The resulting developing roller was evaluated in the same manner as in Example 1.

[0058] (Examples 5, 6, and 7) Developing rollers were produced in the same manner as in Example 2, except that the immersion time was changed to 15 seconds, 30 seconds, and 60 seconds, and evaluated in the same manner as in Example 1.

[0059] Example 8 A polished roller obtained in the same manner as in Example 1 was subjected to EB treatment to prepare a developing roller, which was then evaluated in the same manner as in Example 1. For the EB treatment, an electron beam irradiation device (manufactured by Iwasaki Electric Co., Ltd.) with a maximum acceleration voltage of 150 kV and a maximum electron current of 40 mA was used, and nitrogen gas purging was performed during irradiation. The treatment conditions were acceleration voltage: 150 kV, electron current: 35 mA, treatment speed: 1 m / min, and oxygen concentration: 100 ppm.

[0060] (Comparative Example 1) An addition-curable millable conductive silicone rubber composition was prepared by mixing 1 part by mass of monomethyltrimethoxysilane as a coupling agent with the composition in Table 1. Next, a polished roller obtained in the same manner as in Example 1 was used as a developing roller, and evaluation was carried out in the same manner as in Example 1. (Comparative Example 2) The polished roller obtained in the same manner as in Example 1 was used as a developing roller, and evaluation was carried out in the same manner as in Example 1.

[0061] [Table 3]

[0062] [Table 4]

[0063] [Discussion of evaluation results] The electrophotographic members of Examples 1 to 8 all have a single elastic layer. The elastic layer contains silicone rubber, and all satisfy the condition T1>T2, so filming was suppressed. Furthermore, comparing Examples 1 to 7 with Example 8, the electrophotographic rollers according to Examples 1 to 7 contain a polymer in the first region that is not contained in the second region, and satisfy the condition C1>C2. It was confirmed that the silicone rubber and the polymer form an IPN structure in the first region, which is the outer surface of the elastic layer and extends to a depth of 0.5 μm from the first surface. As a result, even when used as a developing roller to form many electrophotographic images under a harsh environment of high temperature and high humidity, the evaluation result for outer surface wear was Rank A, and the evaluation result for filming was also Rank A or Rank B. These results demonstrate that the electrophotographic rollers according to Examples 1 to 7 have extremely excellent wear resistance and are able to reduce stress on the toner. Comparing Examples 1 to 5 with Examples 6 and 7, Examples 1 to 5 satisfied the condition (T1-T3)>1.0 (°C). Therefore, even when used as a developing roller to form a large number of electrophotographic images under a harsh environment of high temperature and high humidity, the evaluation results for outer surface wear were Rank A, and the evaluation results for filming were also Rank A. From these results, it was found that the electrophotographic rollers according to Examples 1 to 5 had extremely excellent wear resistance and were able to further reduce stress on the toner. Furthermore, when Example 1 and Example 2 are compared, Example 1 has a larger T1-T3 value than Example 2. Therefore, the electrophotographic roller according to Example 1 has a greater filming suppression effect than the electrophotographic roller according to Example 2. The electrophotographic roller according to Comparative Example 1 had an elastic layer formed using silicone rubber containing a silane coupling agent. This elastic layer did not satisfy the condition T1>T2. It is believed that the silicone rubber in this elastic layer was crosslinked by the silane coupling agent, which increased the hardness of the entire elastic layer. As a result, the outer surface wear evaluation result was ranked A, but the filming evaluation result was ranked C. The electrophotographic roller according to Comparative Example 2 had an elastic layer formed using silicone rubber without a silane coupling agent mixed therein. This elastic layer did not satisfy the relationship T1>T2. The entire elastic layer was flexible. Therefore, the evaluation result for filming was Rank A, but the evaluation result for outer surface wear was Rank C.

[0064] The present disclosure includes the following configurations. [Configuration 1] 1. An electrophotographic member having an electrically conductive substrate and a single elastic layer on the substrate, comprising: the elastic layer contains a silicone rubber containing a dimethylsiloxane structure, When the side of the elastic layer facing the substrate is defined as a second surface and the surface of the elastic layer opposite to the second surface is defined as a first surface, T1 (°C) is the peak top temperature of an ion thermogram derived from the dimethylsiloxane structure measured from a first sample sampled from a first region having a thickness of 0.5 μm from the first surface toward the second surface; when the peak top temperature of an ion thermogram attributable to the dimethylsiloxane structure measured from a second sample sampled from a second region of the elastic layer having a thickness of 1.0 μm to 1.5 μm from the second surface toward the first surface is defined as T2 (°C), An electrophotographic member characterized in that T1 and T2 satisfy the relationship represented by the following formula (1): Equation (1) T1 > T2. [Configuration 2] 2. The electrophotographic member according to embodiment 1, wherein T1-T2 is in the range of 3.3°C to 9.1°C. [Configuration 3] the first sample contains a polymer that the second sample does not contain; The peak top temperature of the ion thermogram derived from the polymer measured from the first sample is defined as C1 (°C), When the peak top temperature of an ion thermogram derived from the polymer measured from a third sample obtained by decomposing the silicone rubber contained in the first sample is defined as C2 (°C), The electrophotographic member according to Configuration 1 or 2, wherein C1 and C2 satisfy the relationship represented by the following formula (2): Equation (2) C1 > C2. [Configuration 4] 4. The electrophotographic member according to embodiment 3, wherein C1-C2 is in the range of 0.9°C to 3.6°C. [Configuration 5] 5. The electrophotographic member according to configuration 3 or 4, wherein the polymer is at least one selected from the group consisting of a (meth)acrylic resin, an epoxy resin, and a urethane resin. [Configuration 6] When the peak top temperature of an ion thermogram derived from the dimethylsiloxane structure measured from a fourth sample sampled from a third region of the elastic layer having a thickness of 10.0 μm to 10.5 μm from the first surface toward the second surface is defined as T3 (°C), The electrophotographic member according to any one of Configurations 1 to 5, wherein T1, T2, and T3 satisfy the relationship represented by the following formula (3): Equation (3) T1 > T3 ≧ T2. [Configuration 7] 7. The electrophotographic member according to Constitution 6, wherein T1-T3 is in the range of 0.3°C to 5.9°C. [Configuration 8] The electrophotographic member according to Constitution 6, wherein T1 and T3 satisfy the relationship represented by the following formula (4): Equation (4) T1 > T3 + 1.0(℃). [Configuration 9] 9. The electrophotographic member according to embodiment 8, wherein T1-T3 is 1.3°C to 5.9°C. [Configuration 10] 10. The electrophotographic member according to any one of Configurations 1 to 9, wherein the elastic layer has a thickness of 0.1 mm to 6.0 mm. [Configuration 11] The electrophotographic member according to any one of Configurations 1 to 10, wherein the electrophotographic member is a developing roller. [Configuration 12] 12. An electrophotographic process cartridge configured to be detachably mountable to the main body of an electrophotographic image forming apparatus, the electrophotographic process cartridge comprising the electrophotographic member according to any one of Configurations 1 to 11. [Configuration 13] 13. The electrophotographic process cartridge according to Configuration 12, comprising a developing device containing toner, and having the electrophotographic member as a developing roller. [Configuration 14] 12. An image forming apparatus comprising: an image carrier for carrying an electrostatic latent image; a charging device for primarily charging the image carrier; an exposure device for forming an electrostatic latent image on the primarily charged image carrier; a developing member for developing the electrostatic latent image with toner to form a toner image; and a transfer device for transferring the toner image to a transfer material, wherein the developing member is the electrophotographic member according to any one of Structures 1 to 11. [Explanation of symbols]

[0065] 1: Elastic layer 2: Conductive substrate 21: Image carrier 22: Charging member 24: Developing material 25: Toner supply member 41: First Area 42: The Second Region 43: The Third Realm 44: Elastic layer 45: Conductive substrate 46: First Surface 47: Second Surface

Claims

1. 1. An electrophotographic member having an electrically conductive substrate and a single elastic layer on the substrate, comprising: the elastic layer contains a silicone rubber containing a dimethylsiloxane structure, When the side of the elastic layer facing the substrate is defined as a second surface and the surface of the elastic layer opposite to the second surface is defined as a first surface, T1 (°C) is the peak top temperature of an ion thermogram derived from the dimethylsiloxane structure measured from a first sample sampled from a first region having a thickness of 0.5 μm from the first surface toward the second surface; when the peak top temperature of an ion thermogram derived from the dimethylsiloxane structure measured from a second sample sampled from a second region of the elastic layer having a thickness of 1.0 μm to 1.5 μm from the second surface toward the first surface is defined as T2 (° C.), The T1 and the T2 satisfy the relationship shown in the following formula (1), Formula (1) T1 > T2 T1-T2 is in the range of 3.3°C to 9.1°C; Electrophotographic member characterized by:

2. the first sample contains a polymer that the second sample does not contain; The peak top temperature of the ion thermogram derived from the polymer measured from the first sample is defined as C1 (°C), When the peak top temperature of an ion thermogram derived from the polymer measured from a third sample obtained by decomposing the silicone rubber contained in the first sample is defined as C2 (°C), The C1 and the C2 satisfy the relationship shown in the following formula (2), Formula (2) C1 > C2 C1-C2 is in the range of 0.9°C to 3.6°C; 2. The electrophotographic member of claim 1.

3. 3. The electrophotographic member according to claim 2, wherein the polymer is at least one selected from the group consisting of a (meth)acrylic resin, an epoxy resin, and a urethane resin.

4. When the peak top temperature of an ion thermogram derived from the dimethylsiloxane structure measured from a fourth sample sampled from a third region having a thickness of 10.0 μm to 10.5 μm from the first surface toward the second surface of the elastic layer is defined as T3 (° C.), The T1, T2, and T3 satisfy the relationship shown in the following formula (3): Formula (3) T1 > T3 ≧ T2 2. The electrophotographic member of claim 1.

5. 5. The electrophotographic member of claim 4, wherein T1-T3 is in the range of 0.3°C to 5.9°C.

6. The T1 and T3 satisfy the relationship shown in the following formula (4): Formula (4) T1 > T3 + 1.0 (℃) 5. The electrophotographic member of claim 4.

7. 7. The electrophotographic member of claim 6, wherein T1-T3 is from 1.3°C to 5.9°C.

8. 2. The electrophotographic member of claim 1, wherein the elastic layer has a thickness of from 0.1 mm to 6.0 mm.

9. 2. The electrophotographic member of claim 1, wherein said electrophotographic member is a developer roller.

10. An electrophotographic process cartridge configured to be detachably mountable to a main body of an electrophotographic image forming apparatus, the electrophotographic process cartridge comprising the electrophotographic member according to any one of claims 1 to 8.

11. 11. The electrophotographic process cartridge according to claim 10, further comprising a developing device containing toner, and the electrophotographic member is provided as a developing roller.

12. an image carrier for carrying an electrostatic latent image; a charging device for primarily charging the image carrier; an exposure device for forming an electrostatic latent image on the image carrier that has been primarily charged; a developing member for developing the electrostatic latent image with toner to form a toner image; a transfer device for transferring the toner image onto a transfer material, 9. An electrophotographic image forming apparatus, wherein the developing member is the electrophotographic member according to claim 1.

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