Electrophotographic roller, process cartridge, electrophotographic image forming apparatus, and method for manufacturing electrophotographic roller

Abstract

To provide an electrophotographic roller that reduces excessive electrification of toner, reduces leakage of electric charges from toner, and can achieve a sharp electrification distribution.SOLUTION: An electrophotographic roller has a substrate having a conductive outer surface, and a resin layer present on a side of the outer surface of the substrate. The volume resistivity of the outer surface of the electrophotographic roller is 1.0×106 Ω cm or more. When a corona discharge unit having a grid part is relatively moved at a speed of 400 mm / sec along an axial direction of the electrophotographic roller to electrify the outer surface of the electrophotographic roller, and the electric potential of the outer surface after 0.06 sec from passing of the grid is measured, the maximum value of the electric potential is less than 20.0 V. The ionization potential of the outer surface of the electrophotographic roller is 5.0-5.6 eV. The modulus of elasticity E1 of the electrophotographic roller in an area from the outer surface up to a depth of 0.1 μm is 200 MPa or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an electrophotographic roller, a process cartridge, an electrophotographic image forming apparatus, and a method for manufacturing an electrophotographic roller. [Background technology]

[0002] As the process speed of electrophotographic image forming apparatuses continues to increase, it is considered to apply a high voltage to a toner layer thickness regulating member that is in contact with an electrophotographic roller, and to cause the toner to quickly carry a charge by injecting charge from the toner layer thickness regulating member. Here, one of the problems when applying a high voltage to the toner layer thickness regulating member to cause the toner to carry a charge is excessive charging (charge-up) of the toner, in which more charge than necessary is carried by the toner.

[0003] Patent Document 1 discloses a technology in which the nip passing time, diameter, average circularity, and standard deviation of the circularity of the toner are specified, and a voltage of the same polarity as the toner and an absolute value of 100 to 500 V is applied to the toner on the electrophotographic roller to cause it to carry a charge, thereby improving charging stability and preventing the occurrence of fogging and a decrease in image density. Furthermore, Patent Document 2 discloses a technology for preventing excessive charging of toner in a low-temperature, low-humidity environment by adding a copolymer containing a silicone group, a fluorine group, and a (meth)acrylate in the molecule as a surface modifier to the surface layer of an electrophotographic roller. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-192891 [Patent Document 2] Japanese Patent Application Publication No. 2017-049282 Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, the present inventors considered applying the electrophotographic roller according to Patent Document 2 to an electrophotographic image forming apparatus equipped with a toner layer thickness regulating member to which a high voltage can be applied. However, the present inventors recognized that when the toner on the electrophotographic roller according to Patent Document 2 is made to carry charge by a toner layer thickness regulating member to which a high voltage is applied, excessive charging may occur in a low-temperature, low-humidity environment.

[0006] Toner charging in electrophotography is typically achieved by friction between the toner and a toner layer thickness regulating member or between the toner and an electrophotographic roller. However, the degree of frictional charging is easily affected by the surrounding environment. In particular, in low-temperature, low-humidity environments, excessive toner charging occurs, resulting in a broad charge distribution. Because excessively charged toner has a strong image force with the surface of the electrophotographic roller, the excessively charged toner tends to adhere to the electrophotographic roller. As a result, the surface potential of the electrophotographic roller changes, which can lead to a higher density halftone image.

[0007] The present disclosure is directed to an electrophotographic roller that reduces excessive charging of toner even when an electrophotographic image forming apparatus that applies a high voltage to a toner layer thickness regulating member is used in a low-temperature, low-humidity environment, and that minimizes charge leakage from the toner even in a high-temperature, high-humidity environment, thereby achieving a sharp charge distribution.The present disclosure also relates to a process cartridge and an electrophotographic image forming apparatus that include the electrophotographic roller.The present disclosure also relates to a method for manufacturing the electrophotographic roller. [Means for solving the problem]

[0008] The present disclosure provides an electrophotographic roller having a substrate having a conductive outer surface and a resin layer present on the outer surface side of the substrate, A metal film is provided directly on the outer surface of the electrophotographic roller, and when a direct current voltage of 50 V is applied in an environment of a temperature of 23° C. and a relative humidity of 50%, the volume resistivity is 1.0×10 6 Ω·cm or more, In an environment of a temperature of 23°C and a relative humidity of 50%, a corona charger having a grid portion with a width of 3.0 mm is arranged so that the distance between the grid portion and the outer surface of the electrophotographic roller is 1.0 mm and the direction of the width of the grid coincides with the axial direction of the electrophotographic roller, a voltage of 8 kV is applied to the grid portion, and the corona charger is moved relatively along the axial direction of the electrophotographic roller at a speed of 400 mm / sec to charge the outer surface of the electrophotographic roller, and when the potential of the outer surface is measured 0.06 seconds after the grid has passed, the maximum value of the potential is less than 20.0 V, When an object is irradiated with ultraviolet light at a light intensity of 800 nW and the threshold energy of photoelectron emission at which an ionization potential measurement curve rises sharply is defined as the ionization potential, the ionization potential of the outer surface of the electrophotographic roller is 5.0 to 5.6 eV, The electrophotographic roller has an elastic modulus E1 of 200 MPa or more in a region from the outer surface to a depth of 0.1 μm, measured in a cross section of the resin layer of the electrophotographic roller in the thickness direction.

[0009] The present disclosure also provides a process cartridge configured to be detachably attached to a main body of an electrophotographic image forming apparatus, The process cartridge comprises: an electrophotographic roller; a toner layer thickness regulating member, at least a part of which is electrically conductive, that comes into contact with the electrophotographic roller and regulates the thickness of the toner layer carried on the electrophotographic roller; a contact point electrically connected to the toner layer thickness regulating member, the contact is electrically connected to a contact of the main body of the electrophotographic image forming apparatus when the process cartridge is mounted in the main body of the electrophotographic image forming apparatus, thereby enabling a predetermined voltage to be applied to the toner layer thickness regulating member, The present invention relates to a process cartridge in which the electrophotographic roller is the electrophotographic roller described above.

[0010] The present disclosure further provides an electrophotographic image forming apparatus having a photoreceptor and an electrophotographic roller that supplies toner to an electrostatic latent image formed on the photoreceptor, The present invention relates to an electrophotographic image forming apparatus in which the electrophotographic roller is the electrophotographic roller described above.

[0011] Furthermore, the present disclosure provides a method for manufacturing the electrophotographic roller, comprising: The manufacturing method comprises: providing said substrate having an electrically conductive outer surface; and forming the resin layer on the outer surface side of the substrate; and the step of forming the resin layer includes a step of applying and curing a urethane raw material mixture containing a urethane raw material for forming a cross-linked urethane resin and a surface modifier to obtain a cross-linked urethane resin; The weight average molecular weight Mw of the surface modifier is 200 to 3000. The present invention relates to a method for manufacturing an electrophotographic roller. [Effects of the Invention]

[0012] According to at least one aspect of the present disclosure, an electronic device that applies a high voltage to a toner layer thickness regulating member It is possible to provide an electrophotographic roller that reduces excessive charging of toner even when a photographic image forming apparatus is used in a low-temperature, low-humidity environment, and that reduces charge leakage from toner even in a high-temperature, high-humidity environment, thereby achieving a sharp charge distribution. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic cross-sectional view showing an example of an electrophotographic roller according to the present disclosure. [Figure 2] FIG. 10 is a schematic cross-sectional view showing another example of an electrophotographic roller according to the present disclosure. [Figure 3] FIG. 2 is a schematic diagram of a process cartridge. [Figure 4] FIG. 1 is a schematic diagram of an electrophotographic image forming apparatus. [Figure 5]FIG. 2 is a schematic view showing an example of an apparatus for measuring the electrical resistance of an electrophotographic roller. [Figure 6] FIG. 1 is a schematic diagram showing an example of an apparatus for measuring the surface potential of an electrophotographic roller. [Figure 7] This is an example of the results obtained by ionization potential measurement. [Figure 8] 1 is a cross-sectional view of an electrophotographic roller according to the present invention. [Figure 9] FIG. 1 is a schematic diagram of an electrophotographic image forming apparatus for image evaluation. DETAILED DESCRIPTION OF THE INVENTION

[0014] In the present disclosure, expressions such as "XX or more and YY or less" or "XX to YY" representing a numerical range mean a numerical range including the upper and lower limits, which are the endpoints, unless otherwise specified. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined arbitrarily. Furthermore, in the present disclosure, expressions such as "at least one selected from the group consisting of XX, YY, and ZZ" mean any of XX, YY, ZZ, a combination of XX and YY, a combination of XX and ZZ, a combination of YY and ZZ, or a combination of XX, YY, and ZZ.

[0015] The present inventors speculate that the reason why the electrophotographic roller according to Patent Document 2 cannot sufficiently prevent excessive charging of toner in a low-temperature, low-humidity environment when combined with a toner layer thickness regulating member to which a high voltage is applied is as follows.

[0016] The electrophotographic roller disclosed in Patent Document 2 has a (meth)acrylate copolymer containing a silicone group and a fluorine group in the molecule added as a surface modifier to the resin layer. This addition is thought to bring the ionization potential of the electrophotographic roller closer to that of the toner, thereby reducing frictional charging. Details of ionization potential will be described later. However, when a charge is made to be carried by the toner using a toner layer thickness regulating member to which a high voltage is applied in a low-temperature, low-humidity environment, the electrophotographic roller disclosed in Patent Document 2 is sometimes insufficient in effectiveness. That is, in a low-temperature, low-humidity environment, it is necessary to prevent excessive charging by minimizing frictional charging and to maximize charge injection from the toner layer thickness regulating member in order to obtain sufficient toner charge. Based on this recognition, the present inventors have conducted extensive research and have found that an electrophotographic roller that satisfies the following four requirements is required.

[0017] Requirement (1) A metal film is provided directly on the outer surface of an electrophotographic roller, and when a DC voltage of 50 V is applied in an environment of a temperature of 23°C and a relative humidity of 50%, the volume resistivity is 1.0 x 10 6 Must be Ω·cm or more.

[0018] Requirement (2) In an environment of a temperature of 23°C and a relative humidity of 50%, a corona discharger having a grid portion with a width of 3.0 mm was arranged so that the distance between the grid portion and the outer surface of the electrophotographic roller was 1.0 mm and the direction of the width of the grid coincided with the axial direction of the electrophotographic roller, and a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved in the axial direction of the electrophotographic roller. The outer surface of the electrophotographic roller is charged by moving it relatively at a speed of 400 mm / sec, and the maximum potential of the outer surface is measured 0.06 seconds after the grid has passed through it; the maximum potential is less than 20.0 V.

[0019] Requirement (3) When an object is irradiated with ultraviolet light at a light intensity of 800 nW and the threshold energy of photoelectron emission at which the ionization potential measurement curve rises sharply is defined as the ionization potential, the ionization potential of the outer surface of the electrophotographic roller is 5.0 to 5.6 eV.

[0020] Requirement (4) The modulus of elasticity in a region from the outer surface of the electrophotographic roller to a depth of 0.1 μm, measured in a cross section in the thickness direction of the resin layer of the electrophotographic roller, is 200 MPa or more.

[0021] The above requirements (1) to (4) will be explained in detail below. <Technical significance of requirement (1)> Requirement (1) specifies the volume resistivity of the electrophotographic roller. This volume resistivity is a physical property that indicates the tendency for charge leakage from the toner to the electrophotographic roller. In the area where the toner layer thickness regulating member and the electrophotographic roller come into contact with each other via the toner, a higher voltage is applied to the toner layer thickness regulating member than to the electrophotographic roller. This causes a force to press the toner against the electrophotographic roller. As a result, the toner charge is more likely to leak toward the electrophotographic roller, reducing the toner charge amount, which can lead to toner being transferred to solid white areas on paper, resulting in a degradation of image quality known as "fogging."

[0022] The volume resistivity of the electrophotographic roller is 1.0 x 10 6 By setting the resistivity in the above range, even when a high toner layer thickness regulating member bias is applied, leakage of charge from the toner to the electrophotographic roller is suppressed, and a decrease in the charge amount of the toner can be prevented. The volume resistivity of the electrophotographic roller is preferably 1.0×10 8 The upper limit of the volume resistivity is not particularly limited, for example, 1.0×10 13 Ω·cm or less, preferably 1.0×10 11 Ω·cm or less.

[0023] The volume resistivity of the electrophotographic roller can be controlled by the content of the conductive filler. Specifically, the volume resistivity can be increased by lowering the content of the conductive filler. It is preferable to add the filler at a content that achieves the desired volume resistivity. When the conductive filler is carbon black, it is preferably 5.0 to 45 parts by mass per 100 parts by mass of the resin component that forms the resin layer.

[0024] The volume resistivity is measured using an electrical resistance measuring device. A load of 4.9 N is applied to each end of the mandrel of the electrophotographic roller, and the electrophotographic roller is placed in contact with a metal drum with a diameter of 50 mm. The metal drum is rotated at a surface speed of 50 mm / sec, causing the electrophotographic roller to rotate. A resistor R having a known electrical resistance that is at least two orders of magnitude lower than the electrical resistance of the electrophotographic roller is connected between the metal drum and ground. A voltage of +50 V is applied to the mandrel of the electrophotographic roller from a high-voltage power supply HV, and the potential difference across the resistor R is measured using a digital multimeter DMM (FLUKE 189TRUE RMS MULTIMETER).

[0025] The current flowing through the electrophotographic roller to the metal drum is calculated from the measured value of the potential difference and the electrical resistance of resistor R, and the electrical resistance value of the electrophotographic roller is calculated from this current and the applied voltage of 50V. Measurements using a digital multimeter involve sampling for 3 seconds starting 2 seconds after the voltage is applied, and the value calculated from the average value is taken as the resistance value of the electrophotographic roller. Next, the area of the contact point between the electrophotographic roller and the metal drum is calculated. Electrophotographic roller The volume resistivity of the electrophotographic roller is calculated from the resistance value, the area of the contact portion, and the thickness of the rubber of the electrophotographic roller.

[0026] <Technical significance of requirement (2)> Requirement (2) specifies the surface potential of the electrophotographic roller. The surface potential of the electrophotographic roller indicates the residual charge on the surface of the electrophotographic roller, and is a physical property that indicates the degree of excessive charging of the toner. Toner carrying an electric charge is electrically attracted to the surface of the electrophotographic roller. As the surface potential of the outer surface of the electrophotographic roller increases, this electrical adhesion force becomes stronger, and toner with high adhesion continues to adhere to the electrophotographic roller. As a result, the opportunity for contact between the toner and the electrophotographic roller increases, increasing the amount of triboelectric charge, and causing excessive charging of the toner.

[0027] The surface potential of the electrophotographic roller is less than 20.0 V. By satisfying this range, the electrical adhesion between the toner and the electrophotographic roller is suppressed. This reduces the chance of contact between the toner and the electrophotographic roller, reducing the amount of triboelectric charge and preventing excessive charging of the toner.

[0028] In addition, 0.06 seconds after passing the grid part of the corona discharger, this simulates a model with a high process speed. The surface potential is measured by applying a voltage of 8 kV to the grid portion and moving the corona discharger relatively along the axial direction of the electrophotographic roller at a speed of 400 mm / sec. The maximum value 0.06 sec after the grid portion of the corona discharger has passed is taken as the surface potential of the electrophotographic roller.

[0029] The surface potential of the electrophotographic roller is preferably 10.0 V or less, more preferably 7.0 V or less. The lower the maximum value of the potential of the outer surface, the better, and there is no particular lower limit. The surface potential of the electrophotographic roller is, for example, 0 to 20.0 V, preferably 1.0 to 10.0 V, more preferably 1.5 to 7.0 V.

[0030] The surface potential of the electrophotographic roller can be controlled by the content of the conductive filler and the content and weight-average molecular weight of the surface modifier. The content of the conductive filler is preferably adjusted to achieve the desired surface potential. When the conductive filler is carbon black, the content is preferably 5.0 to 45 parts by mass per 100 parts by mass of the resin components that form the resin layer. Furthermore, by blending the surface modifier in an amount of 1.0 to 5.0 parts by mass per 100 parts by mass of the resin that forms the resin layer and setting the weight-average molecular weight to 3,000 or less, the surface modifier can be prevented from seeping out onto the electrophotographic roller surface. As a result, the formation of an insulating film on the surface of the electrophotographic roller can be prevented, making it easier to maintain a low surface potential.

[0031] <Technical significance of requirement (3)> Requirement (3) specifies the ionization potential of the outer surface of the electrophotographic roller. This ionization potential is a physical property that indicates the frictional electrification of the electrophotographic roller. When two substances with different ionization potentials come into contact, electrons move from the substance with the lower ionization potential to the substance with the higher ionization potential. As a result, the substance with the lower ionization potential becomes positively charged, and the substance with the higher ionization potential becomes negatively charged.

[0032] Generally, when a toner is negatively charged, the ionization potential of the toner often exhibits a high value, typically in the range of 5.0 to 5.6 eV. On the other hand, the ionization potential of the outer surface of the electrophotographic roller of the present disclosure is in the range of 5.0 to 5.6 eV. In other words, the electrophotographic roller is characterized by a small difference in ionization potential between the toner and the surface of the electrophotographic roller. This makes it possible to suppress the transfer of charge from the electrophotographic roller to the toner due to frictional charging when the toner and the electrophotographic roller come into contact with each other. This makes it possible to reduce excessive charging of the toner, particularly in low-temperature, low-humidity environments.

[0033] If the ionization potential of the outer surface of the electrophotographic roller is less than 5.0 eV, image density stability in low-temperature, low-humidity environments tends to decrease. If the ionization potential of the outer surface of the electrophotographic roller is more than 5.6 eV, the toner will be positively charged due to frictional charging when it comes into contact with the electrophotographic roller. As a result, fogging is likely to occur due to insufficient toner charge. The ionization potential of the outer surface of the electrophotographic roller is preferably 5.3 to 5.6 eV.

[0034] The outline of ionization potential measurement is as follows: ultraviolet light emitted from an ultraviolet lamp is selected by a spectrometer and irradiated onto the sample surface. As the photon energy increases, photoelectrons are emitted from the sample material. The energy value at this time is the ionization potential. Detailed measurement conditions are described below.

[0035] <Technical significance of requirement (4)> Requirement (4) specifies the modulus of elasticity in a region from the outer surface of the electrophotographic roller to a depth of 0.1 μm. A high modulus of elasticity in this region indicates that the hardness of the outermost surface of the electrophotographic roller is high. A high hardness on the outermost surface of the electrophotographic roller reduces the contact area with the toner. The degree of triboelectric charging depends on the contact area between the toner and the electrophotographic roller. Therefore, a high hardness on the outermost surface of the electrophotographic roller can suppress triboelectric charging.

[0036] In the present disclosure, if the elastic modulus E1 in the region from the outer surface to a depth of 0.1 μm of the electrophotographic roller is 200 MPa or more, the contact area between the toner and the electrophotographic roller is narrowed, frictional charging is suppressed, and excessive charging of the toner can be reduced, which makes it easier for image density stability to decrease in low-temperature, low-humidity environments.

[0037] The elastic modulus E1 is preferably 200 to 800 MPa, and more preferably 200 to 400 MPa. The elastic modulus E1 can be easily increased by forming an interpenetrating polymer network structure (IPN structure) between the resin of the resin layer and a surface modifier, which will be described later. The elastic modulus E1 can also be easily decreased by lowering the equivalent ratio of the isocyanate group concentration in the polyisocyanate compound to the total active hydrogen group concentration in the polyol. Details of the method for measuring the elastic modulus E1 are as described below.

[0038] To achieve the effects of the present disclosure, requirement (3) is particularly important among the above requirements, but it is also important to satisfy requirements (1), (2), and (4) in addition to requirement (3). By satisfying requirements (2) and (4), the frequency of contact between the toner and the electrophotographic roller can be reduced, and by satisfying requirement (3), the toner charge generated by frictional charging between the toner and the electrophotographic roller can be reduced. The synergistic effect of these factors allows the effects of the present disclosure to be achieved. If requirement (1) is not satisfied, the toner charge is more likely to leak onto the electrophotographic roller, which may result in insufficient fogging suppression. Furthermore, if any of requirements (2) to (4) is not satisfied, the effect of image density stability due to suppression of excessive charging cannot be achieved, and furthermore, the effect of fogging suppression may not be achieved.

[0039] In electrophotographic rollers, the means for satisfying requirement (3) generally include orienting a material with high ionization potential on the surface or forming a film using a material with high ionization potential. However, such methods tend to result in the outermost surface having high resistance, which may not satisfy requirement (2), or the outermost surface having low hardness, which may not satisfy requirement (4), making it difficult to achieve both requirements (2) and (4). The selection of suitable materials and manufacturing conditions will be described later.

[0040] The electrophotographic roller satisfies the requirements (1) to (4), and prevents excessive charging of the toner when an electrophotographic image forming apparatus that applies a high voltage to the toner layer thickness regulating member is used in a low-temperature, low-humidity environment. It is possible to provide an electrophotographic roller that can reduce the charge and achieve a sharp charge distribution.

[0041] The present disclosure will be described in detail below. <Electrophotographic roller> An electrophotographic roller according to at least one embodiment of the present disclosure has a conductive substrate and a resin layer on the outer peripheral surface side of the substrate. An example of an electrophotographic roller is shown in Fig. 1. The electrophotographic roller 10 shown in Fig. 1 has a resin layer 12 laminated on the outer surface, which is the outer peripheral surface of a columnar or hollow cylindrical substrate 11. The layer configuration of the electrophotographic roller is not limited to the form shown in Fig. 1. Other layers may be provided between the substrate 11 and the resin layer 12. Another form of the electrophotographic roller is an electrophotographic roller having an elastic layer 13 as an intermediate layer between the substrate 11 and the resin layer 12 provided on the outer circumferential surface thereof, as shown in Fig. 2. The resin layer 12 is, for example, a surface layer. It is preferable that the resin layer 12 forms the outer surface of the electrophotographic roller.

[0042] [Base] The substrate has a conductive outer surface and functions as a support member for the electrophotographic roller, and in some cases as an electrode. Specific examples of the substrate preferably have a solid columnar or hollow cylindrical shape.

[0043] The material for the substrate can be appropriately selected from those known in the field of electrophotographic conductive members and materials usable for such electrophotographic rollers, and examples thereof include metals or alloys such as aluminum and stainless steel, carbon steel alloys, conductive synthetic resins, iron, and copper alloys.

[0044] Furthermore, the material constituting the substrate may be subjected to an oxidation treatment or a plating treatment with chromium, nickel, or the like. Either electroplating or electroless plating can be used as the type of plating. Electroless plating is preferred from the viewpoint of dimensional stability. Examples of electroless plating that can be used here include nickel plating, copper plating, gold plating, and various other alloy platings. The plating thickness is preferably 0.05 μm or more, and considering the balance between work efficiency and rust prevention ability, the plating thickness is preferably 0.1 to 30 μm.

[0045] A primer may be applied to the surface of the substrate to improve adhesion between the substrate and the resin layer. A known primer can be selected and used depending on the rubber material for forming the conductive layer and the material of the support. Examples of primer materials include thermosetting resins and thermoplastic resins. Specific examples of materials that can be used include phenolic resins, polyurethanes, acrylic resins, polyester resins, polyether resins, and epoxy resins.

[0046] [Resin layer] (binder resin) The resin layer may contain a binder resin. The binder resin of the resin layer is preferably a urethane resin, more preferably a cross-linked urethane resin. Cross-linked urethane resins are suitable as binders because they have excellent flexibility and strength and can form an interpenetrating polymer network structure (IPN structure) described below.

[0047] The urethane resin can be obtained from a urethane raw material containing a polyol, an isocyanate, and, if necessary, a chain extender. The urethane resin may be a cured product of the urethane raw material, or a cured product of a urethane raw material mixture containing the urethane raw material and additives such as a surface modifier and roughness-forming particles. Examples of polyols that are raw materials for the urethane resin include polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, and the like. Among these, polyether polyols are preferred.

[0048] Examples of isocyanates that are raw materials for urethane resins include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthalene diisocyanate (NDI), tolidine diisocyanate (TODI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), phenylene diisocyanate (PPDI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), cyclohexane diisocyanate, polymeric MDI, and mixtures thereof.

[0049] Among the above, polymeric MDI is preferred. Polymeric MDI is a mixture of monomeric MDI and high molecular weight polyisocyanate, and is represented by the following formula (A): n in formula (A) is preferably 0 or more and 4 or less. Commercially available polymeric MDI may be used, and examples thereof include Millionate MR series (manufactured by Tosoh Corporation) such as Millionate MR400 (trade name). [ka]

[0050] Examples of chain extenders, which are raw materials for urethane resins, include difunctional low-molecular-weight diols such as ethylene glycol, 1,4-butanediol, and 3-methylpentanediol, trifunctional low-molecular-weight triols such as trimethylolpropane, and mixtures thereof. Prepolymer-type isocyanate compounds having terminal isocyanate groups, obtained by preliminarily reacting the above-mentioned various isocyanate compounds with various polyols in an excess state of isocyanate groups, may also be used. These isocyanate compounds may also be materials in which the isocyanate groups are blocked with various blocking agents such as MEK oxime. Furthermore, monools such as polyether monools may be used as the urethane raw material.

[0051] Regardless of which material is used, a urethane resin can be obtained by reacting a polyol with an isocyanate under heating. Furthermore, if either or both of the polyol and isocyanate have a branched structure and three or more functional groups, the resulting urethane resin will be a crosslinked urethane resin.

[0052] (surface modifier) In order to control the ionization potential of the outer surface of the electrophotographic roller to a range of 5.0 to 5.6 eV, it is preferable that a material containing silicon and / or fluorine is cured near the surface in the resin layer to form an IPN structure described below with the crosslinked urethane resin. Specifically, it is preferable to use a surface modifier in the resin layer of the electrophotographic roller. The surface modifier is preferably a (meth)acrylate monomer and / or oligomer having at least one or both of a silicone group and a fluorine group in the molecule. That is, the resin layer (preferably a crosslinked acrylic resin) contains at least one group selected from the group consisting of a silicone group and a fluorine group in the molecule. It is preferable to have

[0053] By using these, it becomes easy to control the ionization potential in the range of 5.0 to 5.6 eV. Specifically, the ionization potential of the outer surface of the electrophotographic roller can be increased by adding the above-mentioned silicon- and / or fluorine-containing material to the resin layer and orienting the surface. Furthermore, the weight-average molecular weight of the surface modifier is large, and a surface modifier containing a fluorine group rather than a silicone group has higher surface orientation and is therefore easier to increase the ionization potential.

[0054] The acrylate monomer or oligomer used here is preferably a polyfunctional monomer or oligomer having a plurality of acryloyl groups or methacryloyl groups as functional groups, so as to be easily incorporated into the IPN structure.

[0055] Specifically, the (meth)acrylate monomer or oligomer having a silicone group in the molecule is a (meth)acrylate monomer or oligomer having a structure of the following formula (1): The silicone group preferably has a siloxane structure, more preferably has a structure of the following formula (1). [ka]

[0056] In formula (1), R 1 ,R 2 are each independently H or a hydrocarbon group having 1 to 4 carbon atoms (for example, an alkyl group). Examples of the (meth)acrylate monomer or oligomer having a silicone group in the molecule include silicone (meth)acrylates such as silicone di(meth)acrylate and silicone hexa(meth)acrylate; and trifunctional alkylalkoxysilanes such as 3-methacryloxypropyltrimethoxysilane.

[0057] Specifically, the (meth)acrylate monomer or oligomer having a fluorine group in the molecule is a (meth)acrylate monomer or oligomer having the structure of the following formula (2). For example, a fluorine-modified acrylate can be used. (Meth)acrylic acid alkyl ester in which at least a portion of the alkyl group is substituted with fluorine can be used. [ka] In equation (2), R 1 ,R 2 R each independently represents F or a hydrocarbon group having 1 to 4 carbon atoms (for example, an alkyl group). 1 ,R 2 At least one of the above indicates F.

[0058] Specifically, the (meth)acrylate monomer or oligomer having a silicone group and a fluorine group in the molecule is a (meth)acrylate monomer or oligomer represented by the formula (1) above, 1 ,R 2 At least one of the following is true: (number of carbon atoms) It is a (meth)acrylate monomer or oligomer having a fluoroalkyl group structure (1 to 4). For example, fluorine / acrylic-modified organopolysiloxane can be mentioned.

[0059] From the viewpoint of surface orientation and compatibility when the surface modifier is mixed with the raw material of the urethane resin binder resin, the weight-average molecular weight (Mw) of the surface modifier is preferably 200 to 3000, more preferably 230 to 2100. A weight-average molecular weight of 200 or more facilitates phase separation and surface orientation during the coating and curing process of the resin layer. Furthermore, a weight-average molecular weight of 3000 or less facilitates compatibility of the surface modifier. A weight-average molecular weight of 3000 or less can prevent the acrylate monomer or oligomer from seeping out onto the surface of the electrophotographic roller. Therefore, the surface modifier can be prevented from forming an insulating film on the surface of the electrophotographic roller, making it easy to maintain a low surface potential.

[0060] The amount of the surface modifier to be added is preferably 1.0 to 5.0 parts by mass, and more preferably 3.0 to 5.0 parts by mass, relative to 100 parts by mass of the resin that constitutes the resin layer.

[0061] (cross-linked acrylic resin) The resin layer preferably contains a cross-linked urethane resin and a cross-linked acrylic resin. In the resin layer, the cross-linked urethane resin and the cross-linked acrylic resin preferably have an interpenetrating polymer network structure (IPN structure). The IPN structure is defined as a structure in which the network structures of two or more polymer compounds are intertwined and entangled with each other without being linked by covalent bonds. The IPN structure in the resin layer is preferably formed by the cross-linked acrylic resin penetrating into the network of the three-dimensional cross-linked structure of the cross-linked urethane resin.

[0062] Cross-linked acrylic resin is harder than cross-linked urethane resin, making it possible to increase the hardness of the outermost surface. However, because cross-linked acrylic resin alone is insulating, the surface potential can become extremely high. Furthermore, because cross-linked acrylic resin is brittle, it is prone to scratches caused by abrasion due to friction. On the other hand, when the cross-linked acrylic resin penetrates the three-dimensional cross-linked mesh of the cross-linked urethane resin very close to the outer surface of the resin layer, an IPN structure is formed, which makes it less likely to develop hardness and brittleness, and it is possible to impart high strength while maintaining flexibility.

[0063] Furthermore, the crosslinked acrylic resin is preferably formed by polymerizing a (meth)acrylate monomer or oligomer having a silicone group and / or a fluorine group in the molecule, which is a surface modifier, with a (meth)acrylic monomer by impregnation.

[0064] The following method is preferred for forming an IPN structure of cross-linked acrylic resin and cross-linked urethane resin on or near the outer surface of the resin layer: A resin layer containing cross-linked urethane is impregnated with a liquid (meth)acrylic monomer, which is then cured simultaneously with a surface modifier (a (meth)acrylate monomer or oligomer having a silicone group and / or a fluorine group in the molecule) in the resin layer. The content of the cross-linked acrylic resin in the resin layer relative to 100 parts by mass of the cross-linked urethane resin is preferably 1.0 to 5.0 parts by mass, and more preferably 3.0 to 5.0 parts by mass. The thickness of the resin layer is, for example, 3 to 50 μm, preferably 5 to 30 μm, and more preferably 7 to 20 μm.

[0065] The types of (meth)acrylic monomers used here include polyfunctional monomers having multiple acryloyl groups or methacryloyl groups as functional groups in order to form a crosslinked structure. The (meth)acrylic monomers used for the crosslinked acrylic resin are preferably difunctional (meth)acrylic monomers or trifunctional (meth)acrylic monomers, and it is preferable to use these in combination. The bifunctional (meth)acrylic monomer is preferably at least one selected from the group consisting of alkylene glycol di(meth)acrylates and alkylene oxide (ethylene oxide, propylene oxide) modified alkylene glycol di(meth)acrylates, such as propylene oxide modified neopentyl glycol diacrylate. Examples of trifunctional (meth)acrylic monomers include trimethylolpropane tri(meth)acrylate and pentaerythritol tri(meth)acrylate.

[0066] The polymerization method of the (meth)acrylic monomer is not particularly limited, and known methods can be used. Specific examples include heating and ultraviolet irradiation. Known radical polymerization initiators and ionic polymerization initiators can be used for each polymerization method. These polymerization initiators may be used alone or in combination of two or more.

[0067] Known heating devices and ultraviolet irradiation devices can be used as appropriate. Examples of light sources that can be used to irradiate ultraviolet light 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.

[0068] (Roughness forming particles (resin particles)) Resin particles may be added to the resin layer to form convex portions on the surface of the electrophotographic roller. To provide the resin layer with surface roughness, fine particles for imparting roughness to the resin layer may be added. Specifically, fine particles of polyurethane resin, polyester resin, polyether resin, polyamide resin, acrylic resin, or polycarbonate resin can be used. These are preferably crosslinked resin particles. When an IPN structure is formed on the outer surface of the resin layer, an IPN structure may also be formed inside the crosslinked resin particles. The volume average particle size of the fine particles is preferably 1.0 μm or more and 30 μm or less, and the surface roughness (ten-point average roughness) Rzjis formed by the fine particles is preferably 0.1 μm or more and 20 μm or less, where Rzjis is a value measured in accordance with JIS B0601 (1994). The content of the resin particles is, for example, 1 to 25 parts by mass, preferably 5 to 15 parts by mass, relative to 100 parts by mass of the resin component that forms the resin layer.

[0069] (Conductive filler) Examples of conductive fillers include: carbon-based materials such as carbon black and graphite; metals or alloys such as aluminum, silver, gold, tin-lead alloys, and copper-nickel alloys; metal oxides such as zinc oxide, titanium oxide, aluminum oxide, tin oxide, antimony oxide, indium oxide, and silver oxide; and various fillers plated with conductive metals such as copper, nickel, and silver. Carbon black is particularly preferred as a conductive filler because its conductivity can be easily controlled and it is inexpensive. Of these, fillers with a relatively small primary particle size and hydrophobic properties are particularly preferred because they provide good uniform dispersion within the resin layer.

[0070] Considering the reinforcing performance and conductivity of the resin layer, the number-average primary particle size of the carbon black is preferably in the range of 20 nm to 60 nm. Regarding the surface properties of the carbon black, a pH of 3.0 to 8.0 is preferred. Furthermore, the carbon black content is preferably 5% to 45% by mass relative to 100 parts by mass of the resin component that forms the resin layer.

[0071] (Other additives) In addition to the above-mentioned substances, the resin layer may contain a crosslinking agent, a crosslinking aid, a plasticizer, a filler, an extender, a vulcanizing agent, a vulcanization aid, an antioxidant, an anti-aging agent, a processing agent, etc., to the extent that the above-mentioned functions are not impaired. Various additives such as auxiliaries, dispersants and leveling agents may be contained.

[0072] [Middle layer (elastic layer)] The electrophotographic roller may have an elastic layer as an intermediate layer 13 on the outer surface of the substrate. The electrophotographic roller has the elastic layer between the substrate and the resin layer, for example. There are no particular limitations on the elastic layer, and any known elastic layer for electrophotographic rollers may be used. For example, a cured product of an addition-curing liquid silicone rubber mixture may be used. The thickness of the intermediate layer may be, for example, 1.0 to 10.0 mm, or 2.0 to 5.0 mm.

[0073] Known addition-curing liquid silicone rubbers can be used, such as liquid dimethylpolysiloxanes having two or more silicon-bonded alkenyl groups per molecule, liquid dimethylpolysiloxanes having two or more silicon-bonded hydrogen atoms per molecule, etc. Addition-curing liquid silicone rubber mixtures may also contain fillers such as carbon black.

[0074] (Resin layer manufacturing method) The method for manufacturing an electrophotographic roller preferably includes a step of preparing a substrate having a conductive outer surface and a step of forming a resin layer on the outer surface side of the substrate. The step of forming the resin layer preferably includes a step of applying and curing a urethane raw material mixture containing a urethane raw material that forms a crosslinked urethane resin and a surface modifier to obtain a crosslinked urethane resin. Furthermore, it is preferable to impregnate the crosslinked urethane resin with a (meth)acrylic monomer that forms a crosslinked acrylic resin, and polymerize the surface modifier and the (meth)acrylic monomer to form a crosslinked acrylic resin, thereby obtaining the resin layer.

[0075] As described above, the surface modifier is preferably a (meth)acrylate monomer and / or oligomer having at least one of a silicone group and a fluorine group in the molecule. As described above, the weight average molecular weight Mw of the surface modifier is preferably 200 to 3,000. Before the step of forming the resin layer, a step of forming an elastic layer on the outer surface of the substrate may be carried out. The elastic layer can be obtained, for example, by applying a silicone rubber mixture to the outer surface of the substrate and curing it.

[0076] The method for forming the resin layer containing the crosslinked urethane resin is not particularly limited, but a coating molding method using a liquid paint is preferred. For example, it is preferable to disperse and mix the materials for the resin layer in a solvent to form a urethane raw material mixture, and then coat the resulting paint on a conductive substrate and dry or heat cure it.

[0077] As the solvent, a polar solvent is preferred from the viewpoint of compatibility with polyols and isocyanate compounds, which are raw materials for the crosslinked urethane resin. Examples of polar solvents 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. Of these, solvents that are compatible with other materials can be used alone or in combination of two or more.

[0078] The solid content of the paint can be freely adjusted by the amount of solvent mixed, but is preferably 20% by mass or more and 40% by mass or less from the viewpoint of uniformly dispersing the electronically conductive material such as carbon black (described later). For dispersion and mixing, known dispersion devices using beads, such as a sand mill, paint shaker, dyno mill, or pearl mill, can be used. The coating method can be dip coating, ring coating, spray coating, or roll coating.

[0079] For example, polyol, which is a raw material for the binder resin, an isocyanate compound, a conductive filler, a surface modifier, an additive, etc. are mixed to obtain a liquid coating material. Then, the resin layer coating material is applied to the substrate. After that, the resin layer coating material is dried and solidified or heated and cured to form a crosslinked resin. At this time, by setting the weight-average molecular weight of the surface modifier to 200 to 3000, it is easy to orient the surface modifier near the surface without exuding it to the surface. At this point, the surface modifier exists in an unreacted state near the surface in the crosslinked urethane resin chain.

[0080] Next, the resin layer formed as described above is impregnated with a liquid (meth)acrylic monomer. The liquid (meth)acrylic monomer can be used as is or as an impregnation treatment liquid diluted appropriately with various solvents. By appropriately diluting the liquid (meth)acrylic monomer with various solvents, a resin layer with a more uniform surface composition can be obtained.

[0081] The solvent can be freely selected as long as it has both affinity with the resin layer and solubility for the (meth)acrylic monomer, for example, 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.

[0082] In addition, a polymerization initiator is appropriately mixed into the impregnation treatment liquid. Details of the polymerization initiator are as described above. The impregnation method with the impregnation treatment liquid is not particularly limited, but dip coating, ring coating, spray coating, or roll coating can be used. After the impregnation treatment, the air drying time is preferably limited to 15 minutes or less to prevent the surface modifier added to the resin layer from seeping out to the surface due to the solvent in the impregnation treatment liquid. Then, the material is dried at 90°C for 1 hour to volatilize the solvent.

[0083] After the impregnation treatment with the impregnation treatment solution, the (meth)acrylate monomer or oligomer added to the resin layer as a surface modifier and the (meth)acrylic monomer resulting from the impregnation treatment are simultaneously polymerized and cured. As the reaction progresses, the (meth)acrylate monomer or oligomer added to the resin layer is bulky and thus hardens while oriented toward the outermost surface. This process facilitates the formation of an IPN structure in which the groups derived from the surface modifier, such as silicone groups and / or fluorine groups, are oriented toward the outermost surface, and the interlocking IPN structure is easily formed near the surface of the crosslinked urethane resin network structure. The polymerization and curing methods are not particularly limited, and known methods can be used. Specific examples include heat curing and ultraviolet irradiation.

[0084] <Process cartridge and electrophotographic image forming apparatus> The process cartridge is configured to be detachably mountable to the main body of the electrophotographic image forming apparatus, and preferably includes an electrophotographic roller, a toner layer thickness regulating member, at least a portion of which is conductive, that contacts the electrophotographic roller and regulates the layer thickness of the toner carried on the electrophotographic roller, and a contact point electrically connected to the toner layer thickness regulating member. When the process cartridge is mounted in the main body of an electrophotographic image forming apparatus, this contact electrically connects to the main body contact of the main body of the electrophotographic image forming apparatus, thereby enabling a predetermined voltage to be applied to the toner layer thickness regulating member.

[0085] The electrophotographic roller according to the present disclosure can be suitably used as a developing roller, a toner supply roller, and a developing sleeve in a process cartridge. FIG. 3 is a schematic cross-sectional view of an example of a process cartridge according to one embodiment of the present disclosure. In FIG. 3, the electrophotographic roller is mounted as a developing roller 14. A process cartridge 22 is configured to be detachably mountable to the main body of an electrophotographic image forming apparatus. The process cartridge 22 integrates a developing device 18 including the developing roller 14 and a developing blade 15, a photoreceptor 19, a charging roller 20, and a cleaning blade 21. The developing device 18 is further filled with toner 16. The toner 16 is supplied to the surface of the developing roller 14 by a toner supply roller 17, and a layer of toner 16 of a predetermined thickness is formed on the surface of the developing roller 14 by the developing blade 15.

[0086] The developing roller 14 is in contact with the photosensitive member 19 and is driven to rotate at a predetermined peripheral speed ratio relative to the photosensitive member 19. A predetermined bias is applied to the developing roller 14, and the electrostatic latent image on the photosensitive member 19 is developed with the toner 16 to be visualized.

[0087] The toner supply roller 17 comes into contact with the developing roller 14, penetrates a predetermined amount, and rotates in the same direction as the rotation of the developing roller 14. A bias of the same potential as the bias applied to the developing roller 14 is applied to the toner supply roller 17.

[0088] The toner layer thickness regulating member, at least a portion of which is conductive, is, for example, the developing blade 15. One end of the developing blade 15 is fixed to the developing device 18, and the other free end is arranged in contact with the developing roller 14 in the counter direction to the rotational direction. By arranging the developing blade 15 in contact with the developing roller 14, the amount of toner on the developing roller 14 is regulated, making the toner layer thinner and forming a toner layer of uniform thickness. The process cartridge also has contacts (shown) electrically connected to the toner layer thickness regulating member. These contacts can be electrically connected to main body contacts of the main body of the electrophotographic image forming apparatus, allowing a predetermined voltage to be applied to the developing blade 15. A predetermined bias is applied to the developing blade 15, imparting an electric charge to the toner 16.

[0089] The electrophotographic image forming apparatus has a photosensitive member and an electrophotographic roller that supplies toner to an electrostatic latent image formed on the photosensitive member. The electrophotographic roller is preferably the electrophotographic roller described above.

[0090] FIG. 4 is a schematic cross-sectional view showing an example of an electrophotographic image forming apparatus equipped with an electrophotographic roller as a developing roller of a contact-type developing device using one-component toner. The developing device 18 includes toner 16 as one-component toner, a developing roller 14, a toner supply roller 17 that supplies toner to the developing roller 14, and a developing blade 15 that regulates the thickness of the toner layer on the developing roller 14. The developing roller 14 is located in an opening extending in the longitudinal direction of the developing device 18 and is installed in contact with a photoconductor 19. Note that the photoconductor 19, charging roller 20, and cleaning blade 21 may be provided in the main body of the electrophotographic image forming apparatus. The developing device 18 is equipped with black, cyan, magenta, and yellow toners, enabling color printing.

[0091] The printing operation of an electrophotographic image forming apparatus will now be described. Photoconductor 19 rotates in the direction of the arrow and is uniformly charged by charging roller 20, which charges photoconductor 19. Next, an electrostatic latent image is formed on the surface of photoconductor 19 by laser light 23, which serves as exposure means. The electrostatic latent image is visualized as a toner image (developed) by developing device 18, which applies toner 16 from developing roller 14, which is placed in contact with photoconductor 19. Development is what is known as reversal development, in which a toner image is formed in the exposed area.

[0092] The toner image formed on the photosensitive member 19 is transferred onto an intermediate transfer member 25 in the form of an endless belt by a transfer roller 24 which is a transfer member. Paper 26, which is a recording medium, is fed into the device by paper feed roller 27 and secondary transfer roller 28, and is transported together with intermediate transfer body 25 bearing a toner image to the nip between secondary transfer roller 28 and driven roller 29, where the toner image is transferred to paper 26. Intermediate transfer body 25 is operated by driven roller 29, drive roller 30, and tension roller 31. Toner remaining on intermediate transfer body 25 is cleaned by cleaning device 32.

[0093] A voltage is applied to the developing roller 14, the developing blade 15, the transfer roller 24, and the secondary transfer roller 28 from a bias power supply 33. The paper 26 onto which the toner image has been transferred is fixed by a fixing device 34, and is then ejected from the device, completing the printing operation. Residual toner remaining on the photosensitive member 19 without being transferred is scraped off by a cleaning blade 21, which is a cleaning member for cleaning the surface of the photosensitive member. The cleaned photosensitive member 19 repeats the above printing operation.

[0094] <Volume resistivity> A metal film is provided directly on the outer surface of an electrophotographic roller, and the volume resistivity when a DC voltage of 50 V is applied in an environment of a temperature of 23°C and a relative humidity of 50% can be measured using an electrical resistance measuring device shown in FIG. A load of 4.9 N is applied to both ends of the mandrel of the electrophotographic roller 5, and the electrophotographic roller 5 is placed in contact with a metal drum 6 having a diameter of 50 mm. The metal drum 6 is rotated at a surface speed of 50 mm / sec, and the electrophotographic roller 5 is rotated by the metal drum 6. A resistor R having a known electrical resistance that is two orders of magnitude lower than the electrical resistance of the electrophotographic roller 5 is connected between the metal drum 6 and the ground. A voltage of +50 V is applied to the mandrel of the electrophotographic roller 5 from a high-voltage power supply HV, and the potential difference between both ends of the resistor R is measured using a digital multimeter DMM (for example, a Fluke 189TRUE Measured using an RMS MULTIMETER.

[0095] The current flowing to the metal drum 6 via the electrophotographic roller 5 is calculated from the measured value of the potential difference and the electrical resistance of resistor R, and the electrical resistance value of the electrophotographic roller 5 is calculated from this current and an applied voltage of 50 V. Measurements using a digital multimeter involve sampling for 3 seconds starting 2 seconds after the voltage is applied, and the value calculated from the average value is taken as the resistance value of the electrophotographic roller. Next, the area of the contact portion between the electrophotographic roller 5 and the metal drum 6 is calculated. The volume resistivity of the electrophotographic roller is determined from the resistance value of the electrophotographic roller, the area of the contact portion, and the thickness of the rubber of the electrophotographic roller.

[0096] Specifically, the volume resistivity can be calculated by the following formula.

number

[0097] R: resistance value, S: area of contact part, L: thickness of rubber of electrophotographic roller The meaning of the measurement value is as explained above in <Technical significance of requirement (1)>.

[0098] <Surface potential> The method for measuring the surface potential will be described. The surface potential is measured using a charge amount measuring device (product name: DRA-2000L, manufactured by QEA). Specifically, in an environment of 23°C temperature and 50% relative humidity, a corona discharger having a 3.0 mm wide grid is placed so that the distance between the grid and the outer surface of the electrophotographic roller is 1.0 mm and the width direction of the grid coincides with the axial direction of the electrophotographic roller. Next, a voltage of 8 kV is applied to the grid, and the corona discharger is moved relatively along the axial direction of the electrophotographic roller at a speed of 400 mm / sec to charge the outer surface of the electrophotographic roller. At this time, the potential of the outer surface is measured 0.06 seconds after the grid passes. This makes it possible to evaluate the degree of charge-up on the outer surface of the electrophotographic roller.

[0099] The surface potential of the electrophotographic roller can be measured, for example, by the device shown in Figure 6. Both ends of the substrate 62 of the electrophotographic roller 61 are held by chucks 63, and a measuring unit 66, which has a corona discharger 64 and a surface potential meter 65 arranged in parallel at an interval of 25 mm, is placed facing the surface of the electrophotographic roller 61 at a distance of 1.0 mm. With the electrophotographic roller 61 stationary, a voltage of 8 kV is applied to the grid part of the corona discharger 64, and the measuring unit 66 is moved in the axial direction of the electrophotographic roller 61 at a speed of 400 mm / sec. At this time, The surface potential is measured by the surface potential meter 65 0.06 seconds after the passage of the discharger 64 . The measurement conditions and the meaning of the measured values are as explained above in <Technical significance of requirement (2)>.

[0100] <Ionization potential> The ionization potential is measured by the following measurement method. The ionization potential is expressed numerically as the energy (eV) required to remove an electron from a substance. The ionization potential is measured using a surface analyzer (product name: AC-5, manufactured by Riken Keiki Co., Ltd.). A deuterium lamp is used in the above-mentioned device, and measurements are made under the following conditions. Irradiation power: 800nW Spectrometer: Grating monochromator Spot size: 2mm x 4mm Energy scan range: 4.0 to 6.2 eV Measurement time: 5 sec / energy Then, photoelectrons emitted from the sample surface are detected and processed using ionization potential calculation software installed in the surface analysis device. The measurement is carried out using a rubber piece cut out to a width of 1 cm along the core metal from the electrophotographic roller, and a measurement curve obtained from the average value of three sweeps is used for calculation processing.

[0101] In the surface analysis, when the excitation energy of monochromatic light is scanned from low to high in 0.05 eV intervals, photon emission begins at a certain energy value [eV], and this energy threshold is taken as the ionization potential [eV].

[0102] An example of a work function measurement curve obtained under the above conditions is shown in Figure 7. In Figure 7, the horizontal axis represents excitation energy [eV], and the vertical axis represents the 0.5th power of the number of emitted photoelectrons (normalized quantum yield) Y. Generally, when the excitation energy value exceeds a certain threshold, photoelectrons are rapidly emitted. In other words, the normalized quantum yield increases. The value of excitation energy required when the normalized quantum yield begins to increase is defined as the ionization potential. The meaning of the measurement value is as explained above in <Technical significance of requirement (3)>.

[0103] <Method for measuring elastic modulus> The elastic modulus is measured using a scanning probe microscope (SPM). First, a region including a cross section of the resin layer in the thickness direction of the electrophotographic roller is cut into a thin section using a cryomicrotome (product name: EMFC6, manufactured by Leica Microsystems) with a diamond knife while maintaining the temperature at -110°C. Further, a sample measuring 100 µm square and 100 µm wide in the depth direction is prepared from the thin section.

[0104] 8 shows a schematic cross-sectional view of the resin layer 12 formed on the conductive substrate 11. In the present disclosure, as shown in FIG. 8, a region from the outer surface of the resin layer 12 forming the outer surface of the electrophotographic roller to a depth of 0.1 μm is defined as a first region 81, and a region from the outer surface to a depth of 1.0 to 1.1 μm is defined as a second region 82. The elastic modulus is measured in each region of the cross section of the prepared sample. Measurements are performed using an SPM device (product name: MFP-3D-Origin, manufactured by Oxford Instruments) and a probe (product name: AC160, manufactured by Olympus). After first acquiring a 5 μm square topography image, force curves are measured 10 times in each of the first region 81 and the second region 82, which do not contain the roughness-forming particles or carbon black. The arithmetic mean of the eight points excluding the highest and lowest values is calculated, and the elastic modulus can be calculated using Hertz's theory. The elastic moduli in the first region 81 and the second region 82 are designated E1 and E2, respectively.

[0105] The meaning of E1 in the first area is as explained above in <Technical significance of requirement (3)>. The modulus of elasticity E2 in the second region is at a depth of 1.0 to 1.1 μm from the outer surface. The modulus of elasticity E2 in the region at a depth of 1.0 to 1.1 μm from the outer surface of the electrophotographic roller, measured in a cross section in the thickness direction of the resin layer of the electrophotographic roller, is, for example, 1 to 150 MPa, preferably 1 to 100 MPa, and more preferably 5 to 50 MPa.

[0106] When E2 in the second region is within the above-mentioned range, the load from the electrophotographic roller to the toner is reduced, and filming can be suppressed. It is preferable to simultaneously satisfy E1 and E2. By simultaneously satisfying E1 and E2, only the outermost surface becomes highly hard without increasing the toner load, thereby narrowing the contact area between the toner and the electrophotographic roller. It is preferable to use an IPN structure as a method for increasing the modulus of elasticity E1. This structure easily achieves requirements (2) and (4) simultaneously. Furthermore, E1 can be selectively increased without increasing E2.

[0107] As a method for increasing hardness, for example, a method such as significantly increasing the crosslink density of the rubber constituting the surface of the electrophotographic member can be cited. However, in the case of such a method, the hardening progresses to the inside of the resin layer. Therefore, the load on the toner increases, and filming may occur. In addition, when strengthening the strength by such a method, the flexibility may decrease and embrittlement may occur, and conversely, scratches due to shaving may occur. By setting the elastic modulus E2 at a depth of 1.0 to 1.1 μm from the outer surface within the above range, scratches and filming can be suppressed.

[0108] <Verification of IPN structure> The verification of the IPN structure is performed by micro-sampling mass spectrometry. Micro-sampling mass spectrometry uses an ion trap type mass spectrometer. The sample is fixed to the filament located at the tip of the probe and directly inserted into the ionization chamber. Then, it is rapidly heated from room temperature to a temperature of 1000 °C at a constant heating rate. The sample decomposed and evaporated by heating is ionized by irradiation with an electron beam and detected by a mass spectrometer.

[0109] At this time, under the condition that the heating rate is constant, a thermal chromatogram similar to the TG-MS (thermogravimetry-mass simultaneous analysis) method with a mass spectrum called the total ion chromatogram (TIC) can be obtained. In addition, since a thermal chromatogram for a fragment of a predetermined mass can also be obtained, the peak temperature of the thermal chromatogram corresponding to the decomposition temperature of the desired molecular structure can be obtained. The peak temperature of the thermal chromatogram is correlated with the crosslink structure in the resin structure, and as the crosslinking becomes denser, the peak temperature shifts to the higher temperature side. That is, compared with the crosslinked acrylic resin alone, the part where the crosslinked urethane resin and the crosslinked acrylic resin form an IPN structure has a higher peak temperature in the thermal chromatogram.

[0110] A peak top temperature A1 of a thermal chromatogram derived from a cross-linked acrylic resin is obtained from a first sample obtained from a first region, which is a region extending from the outer surface of the resin layer to a depth of 0.1 μm. Furthermore, a peak top temperature A2 of a thermal chromatogram derived from the cross-linked acrylic resin is measured from a second sample obtained by decomposing the cross-linked urethane resin contained in the first sample. When an IPN structure is formed, A1 will be higher than A2 in terms of the peak temperature of the thermal chromatogram. A2 is a value obtained by performing microsampling mass spectrometry on a second sample obtained after decomposing the crosslinked urethane by the pyridine decomposition method described below. Examples of A1 include 393 to 398°C and 394 to 397°C. Examples of A2 include 390 to 396°C and 391 to 395°C.

[0111] (Pyridine decomposition method) The pyridine decomposition method is a method for selectively decomposing urethane bonds. By performing pyridine decomposition on a sample containing an IPN structure of crosslinked urethane resin, it is possible to obtain a crosslinked acrylic resin after removing the structure derived from the crosslinked urethane. The presence or absence of an IPN structure can be confirmed by capturing changes in the peak temperature of the thermal chromatogram of this crosslinked acrylic resin. Specifically, the pyridine decomposition method is performed as follows.

[0112] Using a microtome, a 0.1 μm thick sample was cut from the outer surface of the resin layer of the electrophotographic roller, and 500 mg of the sample was collected. 0.5 mL of a 3:1 mixture of pyridine (Wako Pure Chemical Industries, Ltd.) and water was added to the resulting sample, which was then decomposed by heating at 130°C for 15 hours in a sealed container made of fluororesin (Teflon®) with a stainless steel jacket. The resulting decomposition product was then subjected to reduced pressure to remove the pyridine. The sample thus obtained was subjected to the microsampling mass spectrometry described above to obtain the A2 value.

[0113] <Structural analysis of cross-linked acrylic resin> The presence of silicone groups and / or fluorine groups in the crosslinked acrylic resin molecules can be analyzed by known means such as pyrolysis GC / MS (gas chromatograph mass spectrometer), FT-IR (Fourier transform infrared spectrometer), and NMR (nuclear magnetic resonance spectrometer). In the present invention, the structure derived from the crosslinked urethane was removed by the pyridine method, and the resulting crosslinked acrylic resin was confirmed using FT-IR (trade name: FT / IR-4700, manufactured by JASCO Corporation, FT-IR).

[0114] <Measurement of surface element amount> When the outer surface of the resin layer of an electrophotographic roller is measured by X-ray photoelectron spectroscopy (ESCA), the method for measuring the percentage of detected Si (Atomic%) and the percentage of detected F (Atomic%) based on the total detected values of F, C, O, Si, and N (hereinafter also referred to as Si / F amount) is as follows: The Si / F content is measured using X-ray photoelectron spectroscopy (ESCA: Electron Spectroscopy for Chemical Analysis). More specifically, this measurement can be performed using an X-ray photoelectron spectrometer (product name: Quantum 2000 Scanning ESCA Microprobe, manufactured by PHI (Physical Electronics Industries, Inc.)) under the following conditions. Then, from the peak intensity of each element obtained, the surface atomic concentration (Atomic %) is calculated using a relative sensitivity factor provided by PHI, and this is taken as the abundance ratio of the Si / F content to the constituent elements at the outermost surface of the resin layer.

[0115] In the present disclosure, at least one of the ratio of the detected value of Si and the ratio of the detected value of F based on the total detected values of F, C, O, Si, and N is preferably 5.0 to 15.0 Atomic%, and more preferably 5.0 to 13.0 Atomic%. Both the ratio of the detected value of Si and the ratio of the detected value of F may be within the above range. It is also preferable that both the ratio of the detected value of Si and the ratio of the detected value of F do not exceed 15.0 Atomic%.

[0116] When the Si / F ratio is within the above range, the surface modifier does not seep out from the resin layer surface and is oriented near the surface, making it easy to raise the ionization potential to 5.0 eV or higher without increasing the surface potential. When the Si / F ratio is 5.0 Atomic% or less, it is difficult to raise the ionization potential of the outermost surface to 5.0 eV or higher. Furthermore, when the Si / F ratio is 15.0 Atomic% or less, there are fewer high-resistance areas on the outermost surface, making it easy to suppress the surface potential.

[0117] The measurement is carried out under the following conditions. Excitation X-ray: Al Kα Photoelectron escape angle: 45° ·X-ray: 100μm 25W 15kV Electronic neutralization gun: 20μA, 1V Ion Neutralization Gun: 7mA, 10V ·Analysis area: 300μm×200μm Pass Energy: 58.70 eV Step Size: 0.125eV ·Sweep: F (10 times), C (10 times), O (10 times), Si (30 times), N (30 times).

[0118] <Measurement of weight average molecular weight> The surface modifier preferably has a weight average molecular weight Mw of 200 to 3000. The meaning of the measured values is as described above. The apparatus and conditions used for measuring the weight average molecular weight are as follows: Measuring equipment: HLC-8120GPC (product name, manufactured by Tosoh Corporation); Column: TSKgel SuperHZMM (product name, manufactured by Tosoh Corporation) x 2; · Solvent: THF; ·Temperature: 40℃; THF flow rate: 0.6ml / min. The measurement sample was a 0.1% by mass THF solution. Furthermore, measurements were performed using an RI (refractive index) detector. A calibration curve was created using TSK standard polystyrenes (trade names: A-1000, A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40, F-80, F-128; manufactured by Tosoh Corporation) as standard samples for creating a calibration curve. Based on this, the weight-average molecular weight was calculated from the retention time of the measurement sample obtained. [Example]

[0119] The present disclosure will be described in more detail below with reference to examples, but these examples are not intended to limit the present disclosure in any way.

[0120] Example 1 [1. Preparation of conductive substrate] A primer (product name: DY35-051, manufactured by Dow Corning Toray Co., Ltd.) was applied to a SUS304 core bar with an outer diameter of 6 mm and a length of 270 mm, and the core bar was heated at a temperature of 150°C for 20 minutes. This core bar was then placed concentrically within a cylindrical mold with an inner diameter of 12.0 mm to serve as a substrate.

[0121] To prepare the intermediate elastic layer, the materials shown in Table 1 below were mixed in a kneader (product name: Trimix TX-15, manufactured by Inoue Seisakusho Co., Ltd.) to form an addition-curing liquid silicone rubber mixture, which was then poured into a mold heated to 115°C. After the material was poured, the mixture was heated and molded at 120°C for 10 minutes, cooled to room temperature, and then demolded from the mold, yielding an elastic roller with a 3.0 mm-thick elastic layer formed on the outer periphery of the base.

[0122] [Table 1]

[0123] [2. Formation of resin layer] The materials for the resin layer, other than the roughness-forming particles listed in Table 2 below, were mixed by stirring. Then, the mixture was dissolved in methyl ethyl ketone (Kishida Chemical Co., Ltd.) to a solids concentration of 30% by mass, mixed, and then uniformly dispersed using a sand mill. Methyl ethyl ketone was added to this mixture to adjust the solids concentration to 25.0% by mass, and the materials listed in the roughness-forming particles column in Table 2 were added, followed by stirring and dispersing using a ball mill to obtain resin layer coating material 1. The elastic roller was immersed in the coating material to coat the resin layer to a thickness of 15 μm, and then heated at 135° C. for 60 minutes to dry and harden the coating, forming a cross-linked urethane resin in the resin layer.

[0124] [Table 2]

[0125] Next, impregnation and curing treatment of an acrylic monomer capable of forming a cross-linked acrylic resin was carried out by the following method. The materials shown in Table 3 below were dissolved and mixed as materials for the impregnation treatment liquid for the impregnation treatment. The elastic roller on which the cross-linked urethane resin had been formed was immersed in this impregnation treatment liquid for 2 seconds to impregnate the acrylic monomer component. Thereafter, it was immediately dried at 90°C for 1 hour to volatilize the solvent. After drying, the elastic roller was rotated and exposed to a cumulative light intensity of 15,000 mJ / cm. 2 The acrylic monomer was cured by irradiating it with ultraviolet light so that an IPN structure was formed, thereby obtaining a resin layer. The ultraviolet irradiation device used was a high-pressure mercury lamp (product name: handy type UV curing device). A device (manufactured by Mario Networks) was used.

[0126] [Table 3]

[0127] The obtained electrophotographic roller was evaluated as follows. [3. Image evaluation] The image evaluation method will be explained below. The electrophotographic image forming apparatus used was a modified version of a commercially available laser printer, the LBP-7600C (manufactured by Canon Inc.). The configuration of the modified apparatus is shown in Figure 9. Modifications included connecting an external high-voltage power supply 20C in addition to power supplies 14C and 15C, allowing any potential difference to be set between the developing blade and the electrophotographic roller, and setting the output rate per unit time to 50 sheets per minute for A4 size paper in order to evaluate a high-speed process. The process cartridge used was a commercially available toner cartridge 318 (black) (manufactured by Canon Inc.), and the developing roller was replaced with the electrophotographic roller of Example 1. At this time, the amount of toner filled was adjusted to 100 g. Note that the product toner was removed from each of the yellow, cyan, and magenta stations, and yellow, cyan, and magenta cartridges with their remaining toner amount detection mechanisms disabled were inserted for evaluation.

[0128] <Fogging evaluation> The prepared process cartridge was installed in the main body of an electrophotographic image forming apparatus and left in an environment of 30°C and 80% relative humidity for 24 hours. Then, an external high-voltage power supply was used to set the potential difference between the development blade and the electrophotographic roller to -300V. Under the same conditions, an image of a 4-point "E" letter was continuously printed on A4 evaluation paper (GF-C081, manufactured by Canon Inc.) with a print coverage of 2% of the A4 paper area. A solid white image was printed every 1,000 sheets, and this process was repeated up to 20,000 sheets. The fogging value was measured using the following method.

[0129] A reflection densitometer (product name: TC-6DS / A, manufactured by Tokyo Denshoku Technology Center Co., Ltd.) was used to measure the reflection density R1 of the recording material before image formation and the reflection density R2 of the recording material with a solid white image printed thereon. The increase in reflection density (R2 - R1) was defined as the "fog value" of the electrophotographic roller. The reflection density was measured across the entire image printing area of the recording material. The arithmetic mean value was used for the recording material before image formation, and the maximum value was used for the recording material with a solid white image printed thereon. Next, the arithmetic mean value of the fog values for each image up to 20,000 sheets was calculated. Note that a smaller fog value is better; typically, toner is not transferred onto the transfer paper on which a solid white image has been formed. If the toner charge is insufficient, toner will migrate onto the photoreceptor even during the formation of a solid white image, and then be transferred onto the transfer paper, increasing the fog value. The evaluation results are shown in Tables 6-1 and 6-2. Incidentally, since fogging tends to occur more easily in high temperature and humidity environments of 30°C and 80% relative humidity, the evaluation was carried out in the above environment.

[0130] <Image density stability evaluation> The prepared process cartridge was installed in the main body of an electrophotographic image forming apparatus and left for 24 hours in an environment with a temperature of 15°C and a relative humidity of 10%. Then, using an external high-voltage power supply, the potential difference between the developing blade and the electrophotographic roller was set to -300 V, and one solid black halftone image, 48 solid white images, and one solid black halftone image were continuously printed in this order. The densities of the obtained halftone images on the first and 50th sheets were measured using a spectrodensitometer (product name: 508, manufactured by Xrite Corporation), and the density difference between the first and 50th sheets was calculated. Note that a smaller density difference is better. The evaluation results are shown in Tables 6-1 and 6-2.

[0131] (Examples 2 to 25, Comparative Examples 1 to 5) Using the same method as in Example 1, each resin layer coating material was prepared using the materials shown in Table 4, each impregnation treatment liquid was prepared using the materials shown in Table 5, and each electrophotographic roller was manufactured using the combinations shown in Tables 6-1 and 6-2. The obtained electrophotographic rollers were evaluated using the same method as in Example 1. The evaluation results are shown in Tables 6-1 and 6-2.

[0132] (Comparative Example 6) Surface modifier A described in the examples of Japanese Patent No. 6510936 was used as a material for the resin layer coating material, and the resin layer coating material was prepared with the materials shown in Table 4, and electrophotographic rollers were produced in the combinations shown in Tables 6-1 and 6-2. Surface modifier A was prepared as follows. A 100 mL reaction flask was charged with 3.08 g (0.67 mmol) of acrylate-modified silicone oil (Shin-Etsu Chemical Co., Ltd., "X-22-174DX"), 8.53 g (19.73 mmol) of 2-(perfluorohexyl)ethyl acrylate (Daikin Industries, Ltd., "R-1620"), 13.08 g (68.03 mmol) of 2-phenoxyethyl acrylate (Tomoe Engineering Co., Ltd., "SR339A"), 1.51 g (11.57 mmol) of 2-hydroxyethyl methacrylate (Tokyo Chemical Industry Co., Ltd.), 1.24 g (4 mmol) of dimethyl 1,1'-azobis(1-cyclohexanecarboxylate) (Fujifilm Wako Pure Chemical Industries, Ltd., "VE-73"), and 22.44 g of methyl ethyl ketone (MEK). The mixture was stirred and bubbled with nitrogen for 5 minutes. The internal liquid was then polymerized at a temperature of 80°C for 7 hours to produce a copolymer. Subsequently, 41.56 g of methyl ethyl ketone (MEK) was added to obtain a surface modifier A with a solids content of 30%. This was used as the surface modifier. Except for this, a resin layer coating material and an impregnation treatment solution were prepared using the materials shown in Tables 4 and 5 in the same manner as in Example 1, and electrophotographic rollers were produced using the combinations shown in Tables 6-1 and 6-2. The obtained electrophotographic rollers were evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 6-1 and 6-2.

[0133] (Comparative Examples 7 to 9) A synthetic liquid containing photopolymerizable polymer A described in the examples of Japanese Patent No. 5968257 was used as the impregnation treatment liquid. Specifically, a 100 mL reaction flask was charged with 1.66 g (0.36 mmol) of acrylate-modified silicone oil (Shin-Etsu Chemical Co., Ltd., "X-22-174DX"), 5.61 g (13 mmol) of 2-(perfluorohexyl)ethyl acrylate (Daikin Industries, Ltd., "R-1620"), 1.69 g (13 mmol) of 2-hydroxyethyl methacrylate (Tokyo Chemical Industry Co., Ltd.), 7.37 g (73.64 mmol) of methyl methacrylate (Junsei Chemical Industry Co., Ltd.), 1.24 g (4 mmol) of dimethyl 1,1'-azobis(1-cyclohexanecarboxylate) (Fujifilm Wako Pure Chemical Industries, Ltd., "VE-73"), and 75 g of methyl ethyl ketone (MEK). The mixture was stirred and bubbled with nitrogen for 5 minutes, and then polymerized at 75°C for 7 hours to produce a copolymer. Then, 2-isocyanatoethyl methacrylate (manufactured by Showa Denko K.K., "Curren 2.02 g (13 mmol) of bismuth tris(MOI) and 0.001 g of bismuth tris(2-ethylhexanoate) (Fujifilm Wako Pure Chemical Industries, Ltd.) were added, and the resulting solution was stirred at 75° C. for 10 hours. The hydroxyl groups of the polymerized units based on 2-hydroxyethyl methacrylate in the copolymer were reacted with the isocyanate groups of 2-isocyanatoethyl methacrylate to obtain a solution containing photopolymerizable polymer A. This was used as a material for the impregnation treatment agent. Except for this, a resin layer coating material and an impregnation treatment solution were prepared using the materials shown in Tables 4 and 5 in the same manner as in Example 1, and electrophotographic rollers were produced using the combinations shown in Tables 6-1 and 6-2. The obtained electrophotographic rollers were evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 6-1 and 6-2.

[0134] (Comparative Example 10) The ultraviolet curable resin described in the examples of JP-A-2008-165214 was used as the paint for the resin layer. Specifically, 60 parts by mass of urethane acrylate oligomer (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "UV3200B"), 20 parts by mass of polar group-containing acrylate monomer (manufactured by Shin-Nakamura Chemical Co., Ltd., "AMO"), 20 parts by mass of bulky substituent-containing acrylate monomer (manufactured by Kyoeisha Chemical Co., Ltd., "IBXA"), 5 parts by mass of 2-butyl-2-ethyl-1,3-propanediol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., "BEPG-A"), 17.6 parts by mass of cross-linked urethane resin particles (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., "Daimic Beads UCN-5090"), 5 parts by mass of silicone acrylate (manufactured by Shin-Etsu Silicone Co., Ltd., "X-22-2458"), 1 part by mass of photopolymerization initiator (manufactured by BASF, "IRGACURE184"), and 29.3 parts by mass of carbon black (manufactured by Asahi Carbon Co., Ltd., "SUNBLACK X15") were mixed to a solids concentration of 30% by mass. The resulting mixture was dissolved in methyl ethyl ketone (Kishida Chemical Co., Ltd.) and mixed, and then uniformly dispersed in a sand mill. Methyl ethyl ketone was added to this mixed solution to adjust the solid concentration to 25% by mass, and the materials shown in the roughness-forming particles column in Table 4 were added to this, and the mixture was stirred and dispersed using a ball mill to obtain resin layer coating 26. The elastic roller was immersed in this coating to coat the resin layer so that the film thickness was 15 μm, and the UV irradiation intensity was 1500 mW / cm 2 The resin layer was formed by curing the resin by UV irradiation at 100°C for 5 seconds. The obtained electrophotographic roller was evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 6-1 and 6-2.

[0135] (Comparative Example 11) This is an electrophotographic roller described in the examples of JP 2020-166227 A, and a modified silicone compound was used in place of silicone and / or fluoroacrylic in the resin layer coating material. Other than that, the resin layer coating material and impregnation treatment liquid were prepared using the materials shown in Tables 4 and 5 in the same manner as in Example 1, and electrophotographic rollers were produced using the combinations shown in Tables 6-1 and 6-2. The obtained electrophotographic rollers were evaluated using the same methods as in Example 1. The evaluation results are shown in Tables 6-1 and 6-2.

[0136] (Comparative Example 12) Surface modifier A described in the examples of Japanese Patent No. 6510936 was used as a material for the resin layer coating material, and each resin layer coating material was prepared using the materials shown in Table 4, and each impregnation treatment liquid was prepared using the materials shown in Table 5. Furthermore, each electrophotographic roller was produced using the combinations shown in Tables 6-1 and 6-2. Surface modifier A was the same as that produced in Comparative Example 6. The obtained electrophotographic rollers were evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 6-1 and 6-2.

[0137] [Table 4]

[0138] *The numbers in the table represent the amount of each material mixed in parts by mass. *The materials listed in the table are as follows: "PTGL1000": Product name; Polyol manufactured by Hodogaya Chemical Co., Ltd. "PTGL3500": Product name; Polyol manufactured by Hodogaya Chemical Co., Ltd. "PTMG650": Product name; Polyol manufactured by Hodogaya Chemical Co., Ltd. US-270: Product name: Silicone-grafted acrylic polyol manufactured by Toa Gosei Co., Ltd. "MR-400" (Millionate MR-400): Product name: Isocyanate compound (polymeric MDI) manufactured by Tosoh Corporation. "UV3200B": Product name: Urethane acrylate oligomer manufactured by Nippon Synthetic Chemical Industry Co., Ltd. "AMO": Product name; Polar group-containing acrylate monomer manufactured by Shin-Nakamura Chemical Co., Ltd. "IBXA": Product name; manufactured by Kyoeisha Chemical Co., Ltd. Bulky substituent-containing acrylate monomer. "BEPG-A": Product name: 2-butyl-2-ethyl-1,3-propanediol diacrylate manufactured by Kyoeisha Chemical Co., Ltd. "SUNBLACK X15": Product name: Carbon black manufactured by Asahi Carbon Co., Ltd. (volatile content: 2.1%). "50HB-100" (Newpol 50HB-100): Product name: Monool (poly(oxyethyleneoxypropylene) glycol monobutyl ether, molecular weight Mn=510) manufactured by Sanyo Chemical Industries, Ltd. "UCN-5090" (Daimic Beads UCN-5090): Product name: Cross-linked urethane resin particles manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., average particle size 9μm. "EBECRYL1360": Product name: Silicone hexaacrylate manufactured by Daicel Allnex Co., Ltd. "KBM503": Product name; 3-methacryloxypropyltrimethoxysilane manufactured by Shin-Etsu Chemical Co., Ltd. "KP-423": Product name; Silicone acrylate, double-ended type, manufactured by Shin-Etsu Chemical Co., Ltd. "KP-415": Product name; Silicone methacrylate, double-ended type, manufactured by Shin-Etsu Chemical Co., Ltd. "EBECRYL8110": Product name: Fluorine-modified acrylate manufactured by Daicel-Allnex Corporation. "Viscoat 8FM": Product name; 1H,1H,5H-octafluoropentyl methacrylate manufactured by Osaka Organic Chemical Industry Ltd. "X-12-2430C": Product name: Fluorine / acrylic modified organopolysiloxane manufactured by Shin-Etsu Chemical Co., Ltd. "Surface modifier A": Surface modifier A described in the examples of Japanese Patent No. 6510936. "TSF4445": Product name; Modified silicone compound manufactured by Momentive Performance Materials Japan LLC. "Omnirad184": Product name; Photopolymerization initiator manufactured by IGM Resins BV.

[0139] [Table 5]

[0140] *The numbers in the table represent the amount of each material mixed in parts by mass. *The materials listed in the table are as follows: "EBECRYL145": Product name; 2-functional acrylic resin manufactured by Daicel Allnex Corporation Monomer. "TMPTA": Product name; Trifunctional acrylic monomer manufactured by Daicel Allnex Corporation. "Pentaerythritol triacrylate": Product name; Trifunctional acrylic monomer manufactured by Shin-Nakamura Chemical Co., Ltd. Photopolymerizable polymer A: Photopolymerizable polymer A described in the examples of Japanese Patent No. 5968257. "Omnirad184": Product name; Photopolymerization initiator manufactured by IGM Resins BV.

[0141] [Table 6-1]

[0142] [Table 6-2] In the table, A1 is the above-mentioned peak top temperature A1 (°C), and A2 is the above-mentioned peak top temperature A2 (°C).

[0143] The present disclosure relates to the following configurations and methods. (Configuration 1) An electrophotographic roller having a substrate having a conductive outer surface and a resin layer present on the outer surface side of the substrate, A metal film is provided directly on the outer surface of the electrophotographic roller, and when a direct current voltage of 50 V is applied in an environment of a temperature of 23° C. and a relative humidity of 50%, the volume resistivity is 1.0×10 6 Ω·cm or more, In an environment of a temperature of 23°C and a relative humidity of 50%, a corona charger having a grid portion with a width of 3.0 mm is arranged so that the distance between the grid portion and the outer surface of the electrophotographic roller is 1.0 mm and the direction of the width of the grid coincides with the axial direction of the electrophotographic roller, a voltage of 8 kV is applied to the grid portion, and the corona charger is moved relatively along the axial direction of the electrophotographic roller at a speed of 400 mm / sec to charge the outer surface of the electrophotographic roller, and when the potential of the outer surface is measured 0.06 seconds after the grid has passed, the maximum value of the potential is less than 20.0 V, When an object is irradiated with ultraviolet light at a light intensity of 800 nW and the threshold energy of photoelectron emission at which an ionization potential measurement curve rises sharply is defined as the ionization potential, the ionization potential of the outer surface of the electrophotographic roller is 5.0 to 5.6 eV, the elastic modulus E1 in a region from the outer surface of the electrophotographic roller to a depth of 0.1 μm, measured in a cross section of the resin layer of the electrophotographic roller in the thickness direction, is 200 MPa or more; Electrophotographic roller characterized by: (Configuration 2) 2. The electrophotographic roller according to claim 1, wherein the resin layer contains a cross-linked urethane resin and a cross-linked acrylic resin. (Configuration 3) 3. The electrophotographic roller according to Configuration 2, wherein the crosslinked acrylic resin contains at least one group selected from the group consisting of a silicone group and a fluorine group in the molecule. (Configuration 4) 4. The electrophotographic roller according to Configuration 2 or 3, wherein in the resin layer, the cross-linked urethane resin and the cross-linked acrylic resin form an interpenetrating polymer network structure. (Configuration 5) When the outer surface of the resin layer is measured by X-ray photoelectron spectroscopy, at least one of the ratio of the detected value of Si and the ratio of the detected value of F based on the total detected values of F, C, O, Si, and N is 5.0 to 15.0 atomic %; 4. The electrophotographic roller according to Configuration 3, wherein both the percentage of the detected value of Si and the percentage of the detected value of F do not exceed 15.0 Atomic %. (Configuration 6) 6. The electrophotographic roller according to any one of Configurations 1 to 5, wherein the elastic modulus E2 in a region at a depth of 1.0 to 1.1 μm from the outer surface of the electrophotographic roller, measured in a cross section in the thickness direction of the resin layer of the electrophotographic roller, is 1 to 100 MPa. (Configuration 7) 7. The electrophotographic roller according to any one of Configurations 1 to 6, wherein the resin layer forms the outer surface of the electrophotographic roller. (Configuration 8) A process cartridge configured to be detachably mounted in a main body of an electrophotographic image forming apparatus, The process cartridge comprises: an electrophotographic roller; a contact member that contacts the electrophotographic roller and regulates the thickness of the toner layer carried on the electrophotographic roller; a toner layer thickness regulating member at least part of which is conductive; a contact point electrically connected to the toner layer thickness regulating member, the contact is electrically connected to a contact of the main body of the electrophotographic image forming apparatus when the process cartridge is mounted in the main body of the electrophotographic image forming apparatus, thereby enabling a predetermined voltage to be applied to the toner layer thickness regulating member, A process cartridge, wherein the electrophotographic roller is the electrophotographic roller according to any one of Configurations 1 to 7. (Configuration 9) An electrophotographic image forming apparatus having a photosensitive member and an electrophotographic roller that supplies toner to an electrostatic latent image formed on the photosensitive member, 8. An electrophotographic image forming apparatus, wherein the electrophotographic roller is the electrophotographic roller according to any one of Configurations 1 to 7. (Method 1) A method for producing an electrophotographic roller according to any one of configurations 1 to 7, The manufacturing method comprises: providing said substrate having an electrically conductive outer surface; and forming the resin layer on the outer surface side of the substrate; and the step of forming the resin layer includes a step of applying and curing a urethane raw material mixture containing a urethane raw material for forming a cross-linked urethane resin and a surface modifier to obtain a cross-linked urethane resin; The weight average molecular weight Mw of the surface modifier is 200 to 3000. 10. A method for manufacturing an electrophotographic roller, comprising: [Explanation of symbols]

[0144] 10 electrophotographic roller, 11 substrate, 12 resin layer, 14 developing roller, 15 developing blade, 16 toner, 17 toner supply roller, 18 developing device, 19 photosensitive member, 20 charging roller, 21 cleaning blade, 22 process cartridge

Claims

1. An electrophotographic roller having a substrate having a conductive outer surface and a resin layer present on the outer surface side of the substrate, A metal film is provided directly on the outer surface of the electrophotographic roller, and when a DC voltage of 50 V is applied in an environment of a temperature of 23° C. and a relative humidity of 50%, the volume resistivity is 1.0×10 ６ Ω cm or more, In an environment of a temperature of 23° C. and a relative humidity of 50%, a corona charger having a grid portion with a width of 3.0 mm is arranged so that the distance between the grid portion and the outer surface of the electrophotographic roller is 1.0 mm and the direction of the width of the grid coincides with the axial direction of the electrophotographic roller, a voltage of 8 kV is applied to the grid portion, and the corona charger is moved relatively along the axial direction of the electrophotographic roller at a speed of 400 mm / sec to charge the outer surface of the electrophotographic roller, and when the potential of the outer surface is measured 0.06 seconds after the grid has passed, the maximum value of the potential is less than 20.0 V, When an object is irradiated with ultraviolet light at a light intensity of 800 nW and the threshold energy of photoelectron emission at which an ionization potential measurement curve rises sharply is defined as the ionization potential, the ionization potential of the outer surface of the electrophotographic roller is 5.0 to 5.6 eV, the elastic modulus E1 in a region from the outer surface of the electrophotographic roller to a depth of 0.1 μm, measured in a cross section of the resin layer of the electrophotographic roller in the thickness direction, is 200 MPa or more; Electrophotographic roller characterized by:

2. 2. The electrophotographic roller according to claim 1, wherein the resin layer contains a cross-linked urethane resin and a cross-linked acrylic resin.

3. 3. The electrophotographic roller according to claim 2, wherein the crosslinked acrylic resin contains at least one group selected from the group consisting of a silicone group and a fluorine group in the molecule.

4. 3. The electrophotographic roller according to claim 2, wherein in said resin layer, said cross-linked urethane resin and said cross-linked acrylic resin form an interpenetrating polymer network structure.

5. When the outer surface of the resin layer is measured by X-ray photoelectron spectroscopy, at least one of the ratio of the detected value of Si and the ratio of the detected value of F based on the total detected values of F, C, O, Si, and N is 5.0 to 15.0 atomic %; 4. The electrophotographic roller according to claim 3, wherein both the detected value percentage of Si and the detected value percentage of F do not exceed 15.0 atomic %.

6. 2. The electrophotographic roller according to claim 1, wherein an elastic modulus E2 measured in a cross section in the thickness direction of the resin layer of the electrophotographic roller in a region at a depth of 1.0 to 1.1 μm from the outer surface of the electrophotographic roller is 1 to 100 MPa.

7. 2. The electrophotographic roller according to claim 1, wherein the resin layer forms the outer surface of the electrophotographic roller.

8. A process cartridge configured to be detachably mounted in a main body of an electrophotographic image forming apparatus, The process cartridge is an electrophotographic roller; a toner layer thickness regulating member, at least a part of which is electrically conductive, that comes into contact with the electrophotographic roller and regulates the thickness of the toner layer carried on the electrophotographic roller; a contact point electrically connected to the toner layer thickness regulating member, the contact is electrically connected to a contact of the main body of the electrophotographic image forming apparatus when the process cartridge is mounted in the main body of the electrophotographic image forming apparatus, thereby enabling a predetermined voltage to be applied to the toner layer thickness regulating member, A process cartridge, wherein the electrophotographic roller is the electrophotographic roller according to any one of claims 1 to 7.

9. An electrophotographic image forming apparatus having a photosensitive member and an electrophotographic roller that supplies toner to an electrostatic latent image formed on the photosensitive member, 8. An electrophotographic image forming apparatus, wherein the electrophotographic roller is the electrophotographic roller according to any one of claims 1 to 7.

10. A method for manufacturing an electrophotographic roller according to any one of claims 1 to 7, comprising the steps of: The manufacturing method comprises: providing said substrate having an electrically conductive outer surface; and forming the resin layer on the outer surface side of the substrate; and the step of forming the resin layer includes a step of applying and curing a urethane raw material mixture containing a urethane raw material for forming a cross-linked urethane resin and a surface modifier to obtain a cross-linked urethane resin; The weight average molecular weight Mw of the surface modifier is 200 to 3000.

10. A method for manufacturing an electrophotographic roller, comprising:

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