Developing roller, developing cartridge, process cartridge and electro-photographic image formation device

Abstract

To provide a developing roller that suppresses triboelectrification to positive charging toner in an electro-photographic image formation device applying a high voltage to a developing blade, and can more surely reduce leaking a charge of the positive charging toner to the developing roller.SOLUTION: A positive charging toner-purpose developing roller has: a conductive substrate; and a resin layer existing on an outer surface side of the substrate. The resin layer contains crosslinked urethane resin, and on an outermost surface of the resin layer, an amino group exists. Ionic intensity derived from the amino group with respect to the total number of detection ions in the resin layer is 1.0% or more. A ratio of a total of detection values of Si, F and CL of the outermost surface of the resin layer is less than 5.0 Atomic%, and an elastic modulus of the resin layer and volume resistivity thereof meet a specific relationship.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] As the process speed of electrophotographic image forming devices continues to increase, it is thought that a high voltage can be applied to a toner layer thickness regulating member that is in contact with a developing roller, and charge can be quickly transferred to the toner by injecting charge from the toner layer thickness regulating member. Patent Document 1 discloses a developing device (developing cartridge) having a toner layer thickness regulating member that frictionally charges positively charged toner and a developing roller made of a urethane coating material. However, when such a developing device (developing cartridge) is used in an electrophotographic image forming apparatus with a high process speed, there is a problem that the amount of charge on the toner is uneven.

[0003] In this disclosure, a process cartridge refers to one that is composed of a drum cartridge and a developing cartridge that is detachably attached to the drum cartridge, and a developing cartridge refers to one that is composed of a developing unit that is mainly composed of a developing roller and a toner layer thickness regulating member, and a toner unit that is mainly composed of a toner storage section. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-243057 Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, the present inventors considered applying the developing roller according to Patent Document 1 to an electrophotographic image forming apparatus capable of applying a high voltage to a toner layer thickness regulating member (developing blade). However, when a toner layer thickness regulating member to which a high voltage is applied causes charge to be carried on the toner on the developing roller according to Patent Document 1, frictional charging occurs in addition to injection charging, which can result in uneven distribution of the charge amount on the toner.

[0006] The uneven distribution of charge on the toner can cause fluctuations in image density and toner transfer to solid white areas on paper, resulting in a degradation of image quality known as "fogging."In particular, as the process speed of electrophotographic image forming devices increases, the occurrence of image density fluctuations and fogging becomes more pronounced.

[0007] At least one aspect of the present disclosure is directed to providing a developing roller that can suppress frictional charging of positively charged toner and more reliably reduce leakage of charge from the positively charged toner to the developing roller in an electrophotographic image forming apparatus that applies a high voltage to a toner layer thickness regulating member. At least one aspect of the present disclosure is directed to providing a developing cartridge that can provide high-quality electrophotographic images even in an electrophotographic image forming apparatus with a high process speed. At least one aspect of the present disclosure is directed to providing a process cartridge that can provide high-quality electrophotographic images even in an electrophotographic image forming apparatus with a high process speed. Furthermore, at least one aspect of the present disclosure is directed to an electrophotographic printer having a high processing speed. The present invention is also directed to providing an electrophotographic image forming apparatus that can provide high-quality electrophotographic images. [Means for solving the problem]

[0008] According to one aspect of the present invention, there is provided a developing roller having a conductive substrate and a resin layer present on an outer surface side of the substrate, the developing roller is a developing roller for positively charged toner, the resin layer contains a cross-linked urethane resin, an amino group is present on the outermost surface of the resin layer, when the outermost surface of the resin layer is measured by a time-of-flight secondary ion mass spectrometer (TOF-SIMS), the ion intensity derived from amino groups relative to all detected ions is 1.0% or more; when the outermost surface of the resin layer is measured by X-ray photoelectron spectroscopy (XPS), the ratio of the total detected values of Si, F, and Cl to the total detected values of F, C, O, Si, N, and Cl is less than 5.0 atomic %; When the elastic modulus in a first region from the outermost surface of the resin layer to a depth of 0.1 μm is defined as E1, E1 is 200 MPa or more, A metal film is provided directly on the outermost surface of the developing 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 The developing roller is characterized by having a resistivity of Ω·cm or more. Furthermore, according to another aspect of the present disclosure, there is provided a developing cartridge including the above-described developing roller. Furthermore, according to another aspect of the present disclosure, there is provided a process cartridge including the above-described developing cartridge. According to yet another aspect of the present disclosure, there is provided an electrophotographic image forming apparatus equipped with the above-described process cartridge. According to yet another aspect of the present disclosure, there is provided an electrophotographic image forming apparatus for forming an image on a recording sheet, the electrophotographic image forming apparatus comprising: an image carrier; toner; a developing roller for carrying the toner; a toner layer thickness regulating member that is in contact with the developing roller and is capable of applying a predetermined voltage to regulate the layer thickness of the toner carried on the developing roller; an exposure device that exposes the image carrier to light to form an electrostatic latent image on the image carrier; a transfer device that transfers onto a recording sheet the toner image formed on the image carrier by developing the electrostatic latent image with the toner; and a fixing device that fixes the toner image transferred onto the recording sheet, wherein the toner is a positively charged toner and the developing roller is the above-mentioned developing roller. [Effects of the Invention]

[0009] According to at least one aspect of the present disclosure, in an electrophotographic image forming apparatus in which a high voltage is applied to a toner layer thickness regulating member, a developing roller can be provided that can suppress frictional charging of positively charged toner and more reliably reduce leakage of charge from the positively charged toner to the developing roller. Furthermore, according to at least one aspect of the present disclosure, it is possible to provide a developing cartridge that can provide high-quality electrophotographic images even in an electrophotographic image forming apparatus with a high process speed. Furthermore, according to at least one aspect of the present disclosure, it is possible to provide a process cartridge that can provide high-quality electrophotographic images even in an electrophotographic image forming apparatus with a high process speed. Furthermore, according to at least one aspect of the present disclosure, it is possible to provide an electrophotographic image forming apparatus that can provide high-quality electrophotographic images even in an electrophotographic image forming apparatus with a high process speed. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a schematic cross-sectional view illustrating an example of a developing roller according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is a schematic cross-sectional view showing another example of a developing roller according to an embodiment of the present disclosure. [Figure 3] FIG. 1 is a schematic diagram of an electrophotographic image forming apparatus. [Figure 4] FIG. 2 is a schematic diagram of a process cartridge. [Figure 5] FIG. 2 is a schematic diagram showing an example of an apparatus for measuring the electrical resistance of a developing roller. [Figure 6] FIG. 2 is a cross-sectional view of a developing roller according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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.

[0012] The present inventors have speculated as follows why the developing roller according to Patent Document 1, when combined with a toner layer thickness regulating member to which a high voltage is applied, causes a distribution in the amount of charge on the toner. The developing roller disclosed in Patent Document 1 uses a urethane-based coating material on the outermost layer. The positively charged toner disclosed in Patent Document 1 uses silica with amino groups as an external additive. The difference in the charge series between the developing roller and the positively charged toner results in triboelectric charging. Here, the term "triboelectric series" refers to the order in which, when two materials are rubbed together (sliding), the material that tends to be positively charged is placed at the top (positive side) and the material that tends to be negatively charged is placed at the bottom (negative side). The charge imparted to the toner during triboelectric charging is easily affected by the shape and particle size of the toner, resulting in a distribution of charge on the toner. Furthermore, leakage of charge injected into the toner to the developing roller also leads to a distribution of charge on the toner. In other words, to achieve a sharper distribution of charge on the toner when combined with a toner layer thickness regulating member to which a high voltage is applied, it is necessary to minimize triboelectric charging, maximize charge injection from the toner layer thickness regulating member, and suppress charge leakage from the toner to the developing roller.

[0013] Based on this understanding, the present inventors have conducted extensive research into developing rollers whose resin layers contain cross-linked urethane resins, and have found that a developing roller that satisfies the following four requirements can solve the above-mentioned problems.

[0014] Requirement (1) The outermost surface of the resin layer of the developing roller must have amino groups, and when the outermost surface is measured using a time-of-flight secondary ion mass spectrometer (TOF-SIMS), the ion intensity derived from the amino groups relative to all detected ions must be 1.0% or more. Requirement (2) When the outermost surface of the resin layer of the developing roller is measured by X-ray photoelectron spectroscopy (XPS), the total amount of detected Si, F, and Cl must be less than 5.0 atomic % (atomic %) based on the total amount of all elements. Requirement (3): When the elastic modulus in a first region from the outermost surface of the resin layer of the developing roller to a depth of 0.1 μm is defined as E1, E1≧200 MPa must be satisfied. Requirement (4) A metal film is directly formed on the outer surface of the developing roller, and the volume resistivity is 1.0 x 10 when a DC voltage of 50 V is applied in an environment of a temperature of 23°C and a relative humidity of 50%. 6 Must be Ω·cm or more.

[0015] That is, a developing roller according to an embodiment of the present disclosure is a developing roller having a conductive substrate and a resin layer present on the outer surface side of the substrate, the developing roller is a developing roller for positively charged toner, the resin layer contains a cross-linked urethane resin, an amino group is present on the outermost surface of the resin layer, when the outermost surface of the resin layer is measured by a time-of-flight secondary ion mass spectrometer (TOF-SIMS), the ion intensity derived from amino groups relative to all detected ions is 1.0% or more; when the outermost surface of the resin layer is measured by X-ray photoelectron spectroscopy (XPS), the ratio of the total detected values of Si, F, and Cl to the total detected values of F, C, O, Si, N, and Cl is less than 5.0 atomic %; When the elastic modulus in a first region from the outermost surface of the resin layer to a depth of 0.1 μm is defined as E1, E1 is 200 MPa or more, A metal film is provided directly on the outermost surface of the developing 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 The developing roller is characterized by: The above requirements (1) to (4) will be explained in detail below.

[0016] <Regarding requirement (1)> Requirement (1) specifies the amount of amino groups present on the outermost surface of the developing roller. This amount of amino groups is a value measured using a time-of-flight secondary ion mass spectrometer (TOF-SIMS). The presence of amino groups on the outermost surface of the developing roller can suppress frictional charging of positively charged toner.

[0017] Positively charged toners can be obtained in two ways: a) by using inorganic particles (such as silica or titanium oxide) that have been surface-treated with a treatment agent containing amino groups as an external additive, and b) by using materials containing amino groups as toner particles. In either case, the presence of amino groups gives the toner positive charging properties.

[0018] Similarly, the present inventors have found that when a developing roller has a certain amount of amino groups on its outermost surface, the difference in the charge series with the positively charged toner is eliminated, thereby suppressing triboelectric charging. This effect makes it possible to suppress triboelectric charging and impart charge to the toner by injection charging, even when combined with a toner layer thickness regulating member to which a high voltage is applied.

[0019] In the developing roller according to the present disclosure, when the outermost surface of the resin layer of the developing roller is measured using a time-of-flight secondary ion mass spectrometer (TOF-SIMS), the ion intensity derived from amino groups relative to all detected ions is 1.0% or more. This ion intensity value refers to the amount of amino groups present on the outermost surface of the developing roller. Having an amino group amount of 1.0% or more on the outermost surface of the developing roller suppresses triboelectric charging when combined with a toner layer thickness regulating member to which a high voltage is applied, allowing charge to be imparted to the toner by injection charging. As a result, toner charge distribution is less likely to occur, and deterioration in image quality can be suppressed. If the amino group amount is less than 1.0%, functional groups other than amino groups (e.g., alkyl chains derived from acrylic resin) constituting the outermost surface of the developing roller become dominant in the triboelectric series, resulting in triboelectric charging with positively charged toner. In the present disclosure, when the developing roller has a plurality of resin layers, the "resin layer" refers to the layer present on the outermost surface unless otherwise specified.

[0020] Although there is no particular upper limit to the amount of amino groups, when introducing amino groups into the outermost surface of the developing roller by polymerization of (meth)acrylic monomers / oligomers having amino groups, the amount of amino groups increases and at the same time the amount of acrylic components also increases. Since the hardness inside the developing roller (modulus of elasticity E2 at a depth of 1.0 μm to 1.1 μm from the outermost surface, which will be described later) becomes large, the amount of amino groups is preferably less than 10.0%.

[0021] The amount of amino groups is preferably 2.0 to 9.0%, and more preferably 3.0 to 5.0%. When amino groups are introduced onto the outermost surface of the developing roller by polymerization of a (meth)acrylic monomer or oligomer having an amino group, the amount of the amino group can be appropriately adjusted by adjusting the number of parts of the (meth)acrylic monomer or oligomer having an amino group added, or by adjusting the amount of amino groups present in the molecule of the (meth)acrylic monomer or oligomer.

[0022] <Regarding requirement (2)> Requirement (2) specifies the total amount of Si, F, and Cl present on the outermost surface of the developing roller. This total amount of Si, F, and Cl is a value measured by X-ray photoelectron spectroscopy (XPS). As described above, positively chargeable toner has amino groups, and the presence of these groups causes the toner to be positively charged. If elements such as Si, F, and Cl are present on the outermost surface of the developing roller, the positively chargeable toner will be negatively charged due to the difference in the charge series between the positively chargeable toner and the developing roller. For this reason, it is preferable that the outermost surface of the developing roller contains as few elements as possible, such as Si, F, and Cl. In the developing roller according to the present disclosure, when the outermost surface of the resin layer is measured by X-ray photoelectron spectroscopy (XPS), the atomic % (atomic %) of the total amount of detected Si, F, and Cl is less than 5.0% based on the total amount of all elements. By keeping the atomic % less than 5.0%, it is possible to prevent positively charged toner from being negatively charged, thereby preventing the occurrence of a distribution in the charge amount of the toner.

[0023] Si, F, and Cl are used as additives and surfactants in surface coatings, and are primarily derived from dispersants for the conductive filler carbon black. While there are no particular restrictions on the lower limit of the atomic percent of the total detected amount of Si, F, and Cl, from the perspective of carbon black dispersibility and conductivity uniformity within the resin layer, the atomic percent of the total detected amount of Si, F, and Cl is preferably 0.0% or more and 4.0% or less, more preferably 0.0% or more and 1.0% or less, even more preferably 0.1% or more and 1.0% or less, and even more preferably 0.2% or more and 1.0% or less. The atomic % of the total amount of detected Si, F, and Cl can be appropriately adjusted by appropriately adjusting the raw material composition used for the resin layer, specifically, by adjusting the number of parts of the additive containing Si, F, and Cl added, or by adjusting the amount of Si, F, and Cl groups present in the molecule of the additive containing Si, F, and Cl, etc.

[0024] <Regarding requirement (3)> Requirement (3) specifies the modulus of elasticity in a region (first region) from the outermost surface of the developing 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 developing roller is high. A high hardness of the outermost surface of the developing roller reduces the contact area with the toner. It is known that the contact area between the toner and the developing roller is positively correlated with the amount of triboelectric charge of the toner. In other words, a smaller contact area between the toner and the developing roller can suppress triboelectric charge of the toner. In the developing roller according to the present disclosure, when the modulus of elasticity in the region from the outermost surface of the developing roller to a depth of 0.1 μm is defined as E1, E1 is 200 MPa or more, which sufficiently reduces the contact area between the toner and the developing roller and suppresses frictional charging of the toner.

[0025] Although the upper limit of E1 is not particularly limited, it is preferably 900 MPa or less, and more preferably 500 MPa or less, from the viewpoint of suppressing the pressure applied to the contact point with the toner and preventing fusion even when a soft toner is used. For the above reasons, E1 is preferably 300 MPa to 900 MPa, and more preferably 350 MPa to 500 MPa.

[0026] Furthermore, when the modulus of elasticity E2 is defined as the region (second region) from 1.0 μm to 1.1 μm deep from the outermost surface of the developing roller, E2 is preferably 1 MPa or more and 100 MPa or less. E2 is more preferably 10 MPa or more and 80 MPa or less, and even more preferably 20 MPa or more and 60 MPa or less. When E2 is within the above range, the load from the developing roller to the toner is reduced, thereby suppressing scratches and toner degradation in durability tests. In the developing roller according to the present disclosure, it is more preferable that E1 and E2 each simultaneously satisfy the above-mentioned preferred numerical ranges. By simultaneously satisfying the preferred numerical ranges for E1 and E2, the outermost surface can be hardened without increasing the load on the toner, thereby reducing the contact area between the toner and the developing roller. A method for increasing the modulus of elasticity E1 is preferably to form an IPN structure, described below, in the resin layer. This structure can selectively increase E1 without increasing E2.

[0027] One way to increase hardness is to significantly increase the crosslink density of the resin layer that forms the outermost surface of the developing roller. However, this approach increases the hardness of the resin layer itself. This increases the load on the toner, resulting in toner degradation in durability tests. Furthermore, increasing the strength using this approach can reduce flexibility and make the toner brittle, exacerbating scratches caused by abrasion.

[0028] <Regarding requirement (4)> Requirement (4) specifies the volume resistivity of the developing roller. This volume resistivity is a physical property that indicates the tendency for charge leakage from the toner to the developing roller. In an electrophotographic image forming apparatus in which a high voltage is applied to a toner layer thickness regulating member in contact with the developing roller and the toner is charged by the injection of charge from the toner layer thickness regulating member, a large voltage is applied to the toner layer thickness regulating member. Therefore, in the area where the toner layer thickness regulating member and the developing roller contact each other via the toner, a force is applied to the toner pressing it toward the developing roller. In this case, if the volume resistivity of the developing roller is low, the charge of the toner will leak to the developing roller.

[0029] The developing roller according to the present disclosure has a metal film directly formed on the outermost surface of the developing roller, and has a volume resistivity of 1.0×10 when a DC voltage of 50 V is applied in an environment of a temperature of 23° C. and a relative humidity of 50%. 6 By ensuring that the resistance is Ω·cm or higher, charge leakage from the toner to the developing roller can be suppressed even when a high voltage is applied to the toner layer thickness regulating member, thereby suppressing the distribution of charge on the toner and, as a result, preventing degradation of image quality.

[0030] The upper limit of the volume resistivity is not particularly limited, but is preferably 1.0×10 9 If the resistivity is Ω·cm or less, excessive charging of the toner can be suppressed, and a decrease in image density and fogging can be easily suppressed. The volume resistivity is preferably 1.0×10 7 Ω·cm~1.0×10 9 Ω·cm, and more preferably 1.0×10 8Ω·cm~5.0×10 8 Ω·cm. The volume resistivity can be appropriately adjusted by adjusting the amount of conductive filler added to the resin layer or by adjusting the composition of the binder resin forming the resin layer. Specifically, the volume resistivity can be increased by reducing the content of the conductive filler.

[0031] Hereinafter, one embodiment of the present disclosure will be described with reference to the drawings, but the present disclosure is not limited to the configuration shown below. <Developing roller> A developing roller according to at least one aspect of the present disclosure has a conductive substrate and a resin layer on the outer peripheral surface side of the substrate. An example of a developing roller is shown in Fig. 1. The developing 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 developing 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 developing roller is a developing 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 outermost surface of the electrophotographic roller. The elastic layer is not particularly limited, and any known elastic layer for a developing roller may be used.

[0032] [Base] The substrate has a conductive outer surface and functions as a support member for the developing roller and, in some cases, as an electrode. Specific examples of the substrate preferably have a solid columnar or hollow cylindrical shape. The material constituting the substrate can be appropriately selected from materials known in the field of electrophotographic conductive materials and materials usable for such developing rollers. Examples include metals and alloys such as aluminum, iron, stainless steel, copper alloys, and carbon steel, as well as conductive synthetic resins. Furthermore, the material constituting the substrate may be subjected to an oxidation treatment or a plating treatment with chromium, nickel, or the like. While both electroplating and electroless plating can be used, electroless plating is preferred from the viewpoint of dimensional stability. Examples of electroless plating used here include nickel plating, copper plating, gold plating, and various other alloy plating. The plating thickness is preferably 0.05 μm or more, and considering the balance between work efficiency and anti-corrosion ability, the plating thickness is preferably 0.1 to 30 μm.

[0033] 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. Specifically, at least one selected from the group consisting of phenolic resins, polyurethanes, acrylic resins, polyester resins, polyether resins, and epoxy resins can be used.

[0034] [Resin layer] (binder resin) The resin layer in the present disclosure contains a cross-linked urethane resin. The resin layer in the present disclosure preferably has a matrix containing a cross-linked urethane resin as a binder. Cross-linked urethane resins are suitable as binder resins because they have excellent flexibility and strength and can form an interpenetrating polymer network structure (hereinafter referred to as an IPN structure) as described below. An 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.

[0035] 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. As the polyol, which is a raw material for the urethane resin, polyols known for synthesizing urethane resins or polyols that can be used for synthesizing urethane resins can be used. Examples of polyol compounds include the following: polycarbonate polyol, polyether polyol, polyester polyol, polyolefin polyols such as polybutadiene polyol and polyisoprene polyol, and ethylene polyols among polyols. Polymer polyols obtained by polymerizing carboxylic unsaturated monomers, polyester polycarbonate copolymer polyols, etc. Among these, polycarbonate polyols and polyester polycarbonate copolymer polyols are preferred.

[0036] Examples of polycarbonate polyols include polynonamethylene carbonate diol, poly(2-methyl-octamethylene) carbonate diol, polyhexamethylene carbonate diol, polypentamethylene carbonate diol, poly(3-methylpentamethylene) carbonate diol, polytetramethylene carbonate diol, polytrimethylene carbonate diol, poly(1,4-cyclohexanedimethylene carbonate) diol, poly(2-ethyl-2-butyl-trimethylene) carbonate diol, and random / block copolymers thereof.

[0037] Examples of polyester polycarbonate copolymer polyols include the following: copolymers obtained by polycondensing the above-mentioned polycarbonate polyols with lactones such as ε-caprolactone, and copolymers of polyesters obtained by polycondensing diols such as 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methylpentanediol, and neopentyl glycol with dicarboxylic acids such as adipic acid and sebacic acid.

[0038] Examples of isocyanates, which are raw materials for urethane resins, include the following substances. At least one selected from the group consisting of 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. Examples of chain extenders, which are raw materials for urethane resins, include at least one selected from the group consisting of bifunctional 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.

[0039] 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]

[0040] 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. Alternatively, a prepolymer-type isocyanate compound having an isocyanate group at its terminal may be used, which is obtained by preliminarily reacting the above-mentioned various isocyanate compounds with various polyols in an excess state of isocyanate groups. Furthermore, these isocyanate compounds may be materials in which the isocyanate groups are blocked with various blocking agents such as 2-butanone oxime (MEK oxime). Regardless of the material used, a urethane resin can be obtained by reacting the polyol and isocyanate by 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.

[0041] The ratio of the number of isocyanate groups to the number of hydroxyl groups in the urethane resin (hereinafter also referred to as the "NCO / OH ratio") is preferably 1.0 to 2.0. If this NCO / OH ratio is 1.0 to 2.0, the crosslinking reaction proceeds, and the bleeding of unreacted components and low-molecular-weight polyurethane, known as "bleeding," is easily suppressed. The NCO / OH ratio is more preferably 1.0 to 1.6. If this NCO / OH ratio is 1.0 to 1.6, bleeding is suppressed and the hardness of the polymer is easily reduced.

[0042] (cross-linked acrylic resin) The resin layer in the present disclosure preferably contains a cross-linked acrylic resin. Furthermore, the cross-linked urethane resin and the cross-linked acrylic resin preferably form an IPN structure. The IPN structure in the resin layer according to this embodiment is preferably formed by the cross-linked acrylic resin penetrating into the mesh of the three-dimensional cross-linked structure of the cross-linked urethane resin. Cross-linked acrylic resin is harder than cross-linked urethane resin, making it possible to increase the hardness of the outermost surface of the resin layer. However, cross-linked acrylic resin alone is insulating, which can result in an extremely high surface potential. Furthermore, cross-linked acrylic resin is brittle, making it prone to scratches caused by friction. On the other hand, when cross-linked acrylic resin penetrates the three-dimensional cross-linked mesh of cross-linked urethane resin very close to the outermost surface of the resin layer, this hardness and brittleness are less likely to occur, and high strength can be achieved while maintaining flexibility.

[0043] Furthermore, in order to suppress triboelectric charging of a positively charged toner, the crosslinked acrylic resin of the present disclosure is preferably formed by polymerization of a (meth)acrylic monomer or oligomer having an amino group. The amino group may be primary, secondary, or tertiary. The type of (meth)acrylic monomer or oligomer used here includes a polyfunctional monomer or oligomer having multiple acryloyl groups or methacryloyl groups as functional groups in order to form a crosslinked structure. The polymerization method for the (meth)acrylic monomer is not particularly limited, and known methods can be used. Specific examples include methods such as 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 types.

[0044] 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 10 to 20 μm.

[0045] 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.

[0046] There are several methods for forming an IPN structure, including a sequential network formation method in which a network of the first component polymer is first formed, followed by swelling with the second component monomer and polymerization initiator, and then a network of the second component polymer is formed, and a simultaneous network formation method in which a first component monomer, a second component monomer, and their respective polymerization initiators, which have different reaction mechanisms, are mixed together and a network is formed simultaneously.

[0047] When the crosslinked acrylic resin has an amino group, it is preferable to use a sequential network formation method to form an IPN structure between the crosslinked acrylic resin having an amino group and the crosslinked urethane resin in the vicinity of the outermost surface of the resin layer. In the simultaneous network formation method, the (meth)acrylic monomer having an amino group, which is the raw material for the acrylic resin, and the isocyanate and polyol, which are the raw materials for the urethane resin, are simultaneously mixed into the coating material. When mixed simultaneously, the (meth)acrylic monomer having an amino group is highly compatible with the isocyanate and polyol, so that when the resin layer of the developing roller is formed by polymerization, the amino group is uniformly present throughout the resin layer.

[0048] Therefore, in order to have a certain amount of amino groups present on the outermost surface of the resin layer, it is necessary to increase the amount of (meth)acrylic monomer having an amino group. However, increasing the amount of (meth)acrylic monomer having an amino group increases the hardness (elastic modulus E2) inside the resin layer. When the hardness inside the resin layer increases, the load on the toner increases during durability, causing deformation and cracking of the toner, resulting in image defects such as fogging and fluctuations in image density. For this reason, it is preferable to use the sequential network formation method rather than the simultaneous network formation method.

[0049] 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.

[0050] The molecular weight of the (meth)acrylic monomer or oligomer is preferably in the range of 200 to 750. By using a molecular weight in this range, an IPN structure can be easily formed relative to the network structure of the cross-linked urethane resin, and the strength of the resin layer can be effectively improved. As mentioned above, the (meth)acrylic monomer is impregnated into the resin layer containing the cross-linked urethane resin. To achieve this, it must have an appropriate viscosity. That is, if the viscosity is high, impregnation is difficult, and if the viscosity is low, it may be difficult to control the impregnation state. Therefore, the viscosity of the (meth)acrylic monomer is preferably 5.0 mPa·s or more and 140 mPa·s or less at 25°C.

[0051] (resin particles) Resin particles may be added to the resin layer for the purpose of forming convex portions on the surface of the developing roller. When the resin layer is to have surface roughness, fine particles for imparting roughness to the resin layer may be contained. Specifically, at least one resin selected from the group consisting of polyurethane resin, polyester resin, polyether resin, polyamide resin, acrylic resin, and polycarbonate resin may be added. Both resin particles can be used. These are preferably crosslinked resin particles. When an IPN structure is formed on the outermost surface of the resin layer, an IPN structure may also be formed inside the crosslinked resin particles. The volume average particle diameter of the 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 particles is preferably 0.1 μm or more and 20 μm or less. Rzjis is a value measured in accordance with JIS B0601 (1994). The content of the resin particles is preferably 1 to 25 parts by mass, or 5 to 15 parts by mass, per 100 parts by mass of the resin component forming the resin layer.

[0052] (Conductive filler) The resin layer may contain a 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 a conductive metal such as copper, nickel, or silver. Carbon black is particularly preferred as a conductive filler because its conductivity can be easily controlled and it is inexpensive. Among these, fillers with a relatively small primary particle size and hydrophobic properties are particularly preferred because they are uniformly dispersed within the resin layer.

[0053] 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, it is preferable that the pH at 20°C is 3.0 to 8.0. The content of the carbon black is preferably 5.0 to 45.0 parts by mass, more preferably 20.0 to 30.0 parts by mass, per 100 parts by mass of the resin component that forms the resin layer.

[0054] (Other additives) In addition to those described above, the resin layer may contain various additives such as a crosslinking agent, a crosslinking aid, a plasticizer, a filler, an extender, a vulcanizing agent, a vulcanization aid, an antioxidant, an antiaging agent, a processing aid, a dispersant, and a leveling agent, as long as the additives do not impair the above functions. In the present disclosure, when other additives are added, it is preferable to select those that do not eliminate amino groups through reaction. Furthermore, when using additives containing elements such as Si, F, and Cl, the amount added must be adjusted so that when the outermost surface of the resin layer of the developing roller is measured by X-ray photoelectron spectroscopy (XPS), the ratio of the total detected values of Si, F, and Cl to the total detected values of F, C, O, Si, N, and Cl is less than 5.0 atomic %.

[0055] [Middle layer (elastic layer)] The developing roller may have an elastic layer as an intermediate layer 13 on the outermost surface of the substrate. The developing 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 developing 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.

[0056] 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.

[0057] (Resin layer manufacturing method) The manufacturing method of the developing roller includes a step of preparing a conductive substrate, and a step of forming a conductive layer on the outer surface of the substrate. It is preferable to have a step of forming a resin layer on the side of the cross-linked urethane resin. 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 cross-linked urethane resin and a surface modifier to obtain a cross-linked urethane resin. Furthermore, it is preferable to impregnate the cross-linked urethane resin with a (meth)acrylic monomer that forms a cross-linked acrylic resin, and polymerize the surface modifier and the (meth)acrylic monomer to form a cross-linked acrylic resin, thereby obtaining a resin layer.

[0058] 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.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.

[0059] 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.

[0060] As the solvent, a polar solvent is preferred from the viewpoint of compatibility with polyols and isocyanate compounds, which are raw materials for the cross-linked urethane resin. Examples of polar solvents include alcohols such as methanol, ethanol, and 1-propanol, ketones such as acetone, 2-butanone (methyl ethyl ketone), and 4-methyl-2-pentanone (methyl isobutyl ketone), and esters such as methyl acetate and ethyl acetate. Among these, solvents that are compatible with other materials can be used alone or in combination of two or more.

[0061] The solid content of the paint can be freely adjusted by the amount of solvent mixed, but is preferably 20.0% by mass or more and 40.0% by mass or less from the viewpoint of uniformly dispersing the electronically conductive material such as carbon black. 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.

[0062] As an example of a specific procedure, first, polyol, which is a raw material for the binder resin, an isocyanate compound, etc., a conductive filler, additives, etc. are mixed to obtain a liquid coating material. Then, the resin layer coating material is applied to the above-mentioned substrate. After that, a resin layer of cross-linked urethane resin is formed by drying and solidifying or by heat curing.

[0063] Next, the formed resin layer is impregnated with a liquid (meth)acrylic monomer or oligomer having an amino group. The impregnation method can be as is, or as an impregnation treatment liquid obtained by appropriately diluting the liquid (meth)acrylic monomer or oligomer with an amino group with various solvents. By appropriately diluting the liquid (meth)acrylic monomer with an amino group with various solvents, a resin layer with a more uniform surface composition can be obtained. The solvent can be freely selected as long as it satisfies both the affinity with the resin layer and the solubility of the (meth)acrylic monomer with an amino group. Examples of suitable solvents include alcohols such as methanol, ethanol, and 1-propanol; ketones such as acetone, 2-butanone (methyl ethyl ketone), and 4-methyl-2-pentanone (methyl isobutyl ketone); and esters such as methyl acetate and ethyl acetate. A polymerization initiator is also 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.

[0064] After the impregnation treatment with the impregnation treatment solution, the (meth)acrylic monomer or oligomer having an amino group is polymerized and cured to form an IPN structure in which the crosslinked urethane resin and the acrylic resin having an amino group are intertwined with each other. The polymerization and curing methods are not particularly limited, and known methods can be used. Specific examples include heat curing and ultraviolet irradiation.

[0065] <Positively charged toner> The positively charged toner according to the present disclosure will be described. The positively charged toner of the present disclosure preferably contains toner particles and an external additive, and the toner particles preferably contain a binder resin, a colorant, and a charge control agent. The toner particles may also contain other additives such as a release agent and a pigment dispersant, as necessary. Specific examples of binder resins include resins that have been widely used in toners, such as polystyrene, styrene-butyl acrylate copolymer, polyester resin, and epoxy resin.

[0066] Methods for producing toner particles include, but are not limited to, pulverization and polymerization. Toners obtained by these methods are called pulverized toner and polymerized toner, respectively. Polymerized toner is preferred as a toner because it has a relatively small particle size distribution on the order of microns. Examples of the polymerization method include emulsion polymerization aggregation, dispersion polymerization, and suspension polymerization, with suspension polymerization being preferred. When toner particles are produced using a polymerization method, the process is, for example, as follows. First, a polymerizable monomer, a colorant, a charge control agent, and optionally other additives are mixed to form a polymerizable monomer composition. This polymerizable monomer composition is placed in an aqueous medium, optionally containing a dispersion stabilizer, after which a polymerization initiator is added and granulation is carried out. Polymerization is then carried out to obtain an aqueous dispersion of toner particles. This aqueous dispersion is washed, dehydrated, and dried to obtain dried toner particles. These dried toner particles are classified as necessary, and external additives and, optionally, a carrier are added to obtain a polymerized toner.

[0067] (Polymerizable Monomer Composition) The polymerizable monomer refers to a compound that can be polymerized. It is preferable to use a monovinyl monomer as the main component of the polymerizable monomer. Examples of the monovinyl monomer include styrene; styrene derivatives such as vinyltoluene and α-methylstyrene; acrylic acid and methacrylic acid; acrylic acid esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and dimethylaminoethyl acrylate; methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and dimethylaminoethyl methacrylate; acrylonitrile, methacrylonitrile, acrylic acid esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and dimethylaminoethyl methacrylate; Examples of suitable monovinyl monomers include acrylic acid derivatives and methacrylic acid derivatives such as vinylamide and methacrylamide; olefins such as ethylene, propylene, and butylene; vinyl halides and vinylidene halides such as vinyl chloride, vinylidene chloride, and vinyl fluoride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; vinyl ketones such as vinyl methyl ketone and methyl isopropenyl ketone; and nitrogen-containing vinyl compounds such as 2-vinylpyridine, 4-vinylpyridine, and N-vinylpyrrolidone. These monovinyl monomers may be used alone or in combination. Among these, styrene, styrene derivatives, and acrylic acid or methacrylic acid derivatives are preferably used as the monovinyl monomer.

[0068] (coloring agent) A colorant is used in the toner particles according to the present disclosure, and when a color toner is produced, black, cyan, yellow, or magenta colorants can be used. As for the colorant, colorants and dyes such as carbon black, titanium black, magnetic powders such as iron zinc oxide and iron nickel oxide, oil black, and titanium white can be used as the black colorant. The black carbon black preferably has a primary particle size of 20 to 40 nm. A particle size within this range is preferred because the carbon black can be uniformly dispersed in the toner and fogging is reduced.

[0069] Examples of cyan colorants that can be used include copper phthalocyanine compounds, derivatives thereof, and anthraquinone compounds. Specific examples include CI Pigment Blue 2, 3, 6, 15, 15:1, 15:2, 15:3, 15:4, 16, 17:1, and 60. Because of their excellent polymerization stability and coloring power, copper phthalocyanines such as CI Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, and 17:1 are preferred, with 15:3 being more preferred.

[0070] Examples of yellow colorants that can be used include compounds such as azo pigments, such as monoazo pigments and disazo pigments, and condensed polycyclic pigments. Specific examples include CI Pigment Yellow 3, 12, 13, 14, 15, 17, 62, 65, 73, 74, 83, 93, 97, 120, 138, 155, 180, 181, 185, and 186. Because of their excellent polymerization stability and coloring power, monoazo pigments such as CI Pigment Yellow 3, 15, 65, 73, 74, 97, and 120 are preferred, and CI Pigment Yellow 74 is more preferred.

[0071] Examples of magenta colorants that can be used include azo pigments such as monoazo pigments and disazo pigments, and condensed polycyclic pigments, etc. Specific examples include CI Pigment Red 31, 48, 57:1, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 149, 150, 163, 170, 184, 185, 187, 202, 206, 207, 209, 251, and CI Pigment Violet 19. Monoazo pigments such as CI Pigment Red 31, 48, 57:1, 58, 60, 63, 64, 68, 112, 114, 146, 150, 163, 170, 185, 187, 206, and 207 are also preferred due to their good polymerization stability and tinting strength.

[0072] The amount of the colorant is preferably 1 to 10 parts by weight based on 100 parts by weight of the monovinyl monomer. In order to stabilize the dispersion state of the colorant in the polymerizable monomer composition, it is preferable to add a pigment dispersant, and preferred examples of the pigment dispersant include coupling agents such as aluminum coupling agents, silane coupling agents, and titanium coupling agents.

[0073] (Charge control agent) The positively chargeable toner according to the present disclosure contains at least a positively chargeable charge control agent, and may further contain a negatively chargeable charge control agent in the amount sufficient to make the toner positively chargeable. Positively chargeable charge control agents include, for example, nigrosine dyes, quaternary ammonium salts, triaminotriphenylmethane compounds, imidazole compounds, polyamine resins, and charge control resins such as copolymers containing quaternary ammonium (salt) groups. Examples of negatively charged control agents include azo dyes containing metals such as chromium, cobalt, aluminum, and iron, salicylic acid metal compounds, alkylsalicylic acid metal compounds, and charge control resins such as sulfonic acid (salt) group-containing copolymers and carboxylic acid (salt) group-containing copolymers.

[0074] The charge control agent used in the positively charged toner according to the present disclosure preferably contains a charge control resin, since this improves the print durability of the toner. Among the charge control agents, a non-resin charge control agent and a charge control resin may be used in combination, or the charge control resin may be used alone. It is more preferable to use the charge control resin alone.

[0075] (Other additives) As another additive, it is preferable to use a molecular weight modifier. Examples of the molecular weight modifier include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, and 2,2,4,6,6-pentamethylheptane-4-thiol. The molecular weight modifier can be added before the start of polymerization or during polymerization. The amount of the molecular weight modifier is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the monovinyl monomer.

[0076] Furthermore, as other additives, it is preferable to add a release agent, since this can improve the releasability of the toner from the fixing roller during fixing. The release agent can be any one that is generally used as a toner release agent without any particular limitation. For example, low-molecular-weight polyolefin waxes such as low-molecular-weight polyethylene, low-molecular-weight polypropylene, and low-molecular-weight polybutylene; terminal-modified polyolefin waxes such as low-molecular-weight polypropylene with molecular terminal oxidation, low-molecular-weight terminal-modified polypropylene with molecular terminals substituted with epoxy groups, block polymers of these and low-molecular-weight polyethylene, low-molecular-weight polyethylene with molecular terminals substituted with epoxy groups, and block polymers of these and low-molecular-weight polypropylene; natural plant waxes such as candelilla, carnauba, rice, Japan wax, and jojoba; paraffin, microcrystalline, and petrolatum. Examples of suitable waxes include petroleum waxes such as cumin and modified waxes thereof; mineral waxes such as montan, ceresin, and ozokerite; synthetic waxes such as Fischer-Tropsch wax; and polyhydric alcohol esters such as pentaerythritol esters such as pentaerythritol tetramyristate, pentaerythritol tetrapalmitate, pentaerythritol tetrastearate, and pentaerythritol tetralaurate, and dipentaerythritol esters such as dipentaerythritol hexamyristate, dipentaerythritol hexapalmitate, and dipentaerythritol hexalaurate. These may be used alone or in combination of two or more. The release agent is used preferably in an amount of 0.1 to 30 parts by weight, more preferably 1 to 20 parts by weight, based on 100 parts by weight of the monovinyl monomer.

[0077] (external additives) The inorganic fine particles used as an external additive preferably have a primary particle number-average particle size of 4 to 80 nm, more preferably 6 to 40 nm. Furthermore, it is more preferable to use inorganic fine particles having a primary particle number-average particle size of 100 to 200 nm in combination with the above inorganic fine particles. This ensures toner fluidity throughout durability and facilitates improved density. The inorganic fine particles are added to improve toner fluidity and control the chargeability of toner particles. In the present disclosure, from the viewpoint of controlling the charge series of the toner, it is preferable to select inorganic fine particles, and inorganic fine particles having amino groups on the surface are preferable. By having amino groups on the surface of inorganic fine particles, the charge series can be controlled to be positively charged, and such inorganic fine particles can be obtained by treating the surface of the inorganic fine particles with a treating agent such as an aminosilane compound or amino-modified silicone oil.

[0078] Examples of the aminosilane compound include γ-aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, Examples include methyldimethoxysilane, aminosilane, N-(2-aminoethyl)3-aminopropyltrimethoxysilane, and N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane. The number average particle size of the primary particles of the inorganic fine particles is measured using a photograph of the toner taken enlarged with a scanning electron microscope (SEM). Examples of inorganic fine particles that can be used include fine particles of silica, titanium oxide, aluminum oxide, zinc oxide, etc., or fine particles of composite oxides thereof. Examples of silica fine particles include dry silica and wet silica, also known as dry process or fumed silica, which are produced by vapor phase oxidation of silicon halides. The amount of inorganic fine particles added is preferably 0.1 to 4.0 parts by mass per 100 parts by mass of toner particles. The content of inorganic fine particles can be determined by fluorescent X-ray analysis using a calibration curve prepared from standard samples.

[0079] <Developing cartridge, process cartridge and electrophotographic image forming apparatus> The developing roller according to the present disclosure can be suitably used as a developing roller or a toner supply roller in a developing cartridge. Furthermore, in one embodiment, a process cartridge may include a developing cartridge equipped with the developing roller according to the present disclosure and an image carrier to which toner is supplied from the developing cartridge and a toner image is formed. In yet another embodiment, an electrophotographic image forming apparatus may include an exposure device that exposes the image carrier of the process cartridge to light to form an electrostatic latent image on the image carrier, a transfer device that transfers the toner image formed in the process cartridge onto a recording sheet, and a fixing device that fixes the image formed on the recording sheet. In yet another embodiment, the developing roller according to the present disclosure can be suitably used as a developing roller or a toner supply roller in an electrophotographic image forming apparatus.

[0080] (Overall configuration of electrophotographic image forming apparatus) 3 is a schematic cross-sectional view of an example of an electrophotographic image forming apparatus according to an embodiment of the present disclosure. As shown in Fig. 3, a main body casing 2 includes a paper feed unit 4 for feeding paper 3 as an example of a recording medium, and an image forming unit 5 for forming an image on the fed paper 3. The paper feed unit 4 mainly comprises a paper feed tray 6 that is detachably attached to the bottom of the main casing 2, and a paper pressure plate 7 that is provided within the paper feed tray 6. The paper feed unit 4 also comprises various rollers 8 that transport the paper 3 and remove paper dust. In the paper feed unit 4 configured in this manner, the paper 3 in the paper feed tray 6 is pushed upward by the paper pressure plate 7, and then transported to the image forming unit 5 by the various rollers 8.

[0081] The image forming section 5 includes an exposure section 9 as an example of an exposure device, a process cartridge 14, a fixing section 15 as an example of a fixing device, and the like. The exposure unit 9 is disposed in the upper part of the main casing 2. The exposure unit 9 irradiates the photosensitive drum 16 with a laser beam based on image data, thereby exposing the photosensitive drum 16 to light. The process cartridge 14 will be described in detail in the next section.

[0082] 3, the fixing unit 15 is provided downstream of the process cartridge 14 and mainly includes a heating roller 17 and a pressure roller 18 that is disposed opposite the heating roller 17 and presses against the heating roller 17. In the fixing unit 15 configured in this manner, the toner transferred onto the paper 3 is thermally fixed while the paper 3 passes between the heating roller 17 and the pressure roller 18. The paper 3 on which the toner has been thermally fixed in the fixing unit 15 is transported by a paper discharge roller 19 provided downstream of the fixing unit 15 and sent onto a paper discharge tray 20.

[0083] (Process cartridge) The process cartridge 14 is structured so as to be detachably attached to the main body casing 2 by appropriately opening a front cover 2A provided on the front side of the main body casing 2. This process cartridge 14 is mainly composed of a drum cartridge 30 and a developing cartridge 40 that is detachably attached to the drum cartridge 30. The drum cartridge 30 may be either fixed within the main body casing 2 or detachable from the main body casing 2.

[0084] [Developing cartridge] The developing cartridge 40 is composed of a developing unit 41 and a toner unit 42. Figure 4 is a schematic cross-sectional view of an example of a process cartridge according to one embodiment of the present disclosure. 4, the developing unit 41 mainly includes a developing case 41A that forms a toner chamber 43, a developing roller 10, a toner layer thickness regulating member 44, and a supply roller 45 that slides against the developing roller 10. A predetermined bias is applied to the toner layer thickness regulating member 44 to impart an electric charge to the toner.

[0085] 4, the toner unit 42 mainly includes a toner case 42A that forms a toner storage chamber 46, and an agitator 47 that transports the toner stored in the toner storage chamber 46 to the toner chamber 43. The toner unit 42 may be configured to be detachable from the developer cartridge 40, or may be fixed to the developer cartridge 40. The toner contained in the toner storage chamber 46 is supplied from the toner storage chamber 46 into the toner chamber 43, and then supplied to the developing roller 10 either directly or via a supply roller 45. As the developing roller 10 rotates, the toner supplied onto the developing roller 10 enters between the toner layer thickness regulating member 44 and the developing roller 10, and is carried on the developing roller 10 as a thin layer of a constant thickness.

[0086] [Drum cartridge] The drum cartridge 30 mainly includes the photosensitive drum 16, a scorotron charger 31, and a transfer roller 32. The photosensitive drum 16 is rotatably supported by a drum case 30A, and is disposed so as to come into contact with the developing roller 10 when the developing cartridge 40 is attached to the drum cartridge 30. The scorotron charger 31 is a positive charging scorotron charger that generates corona discharge from a charging wire made of tungsten or the like, and is configured to uniformly charge the surface of the photosensitive drum 16 to a positive polarity.

[0087] The transfer roller 32 is disposed below the photosensitive drum 16 so as to face and contact the photosensitive drum 16, and is rotatably supported by the drum case 30A. During transfer, a transfer bias is applied to the transfer roller 32 by constant current control. In the process cartridge 14 configured as above, the surface of the photosensitive drum 16 is uniformly positively charged by the scorotron charger 31, and then exposed to high-speed scanning of a laser beam from the exposure unit 9. This reduces the potential of the exposed portion, and an electrostatic latent image based on the image data is formed.

[0088] Here, the electrostatic latent image refers to an exposed portion of the surface of the photosensitive drum 16, which is uniformly positively charged, that is exposed to a laser beam and has a lowered potential. Next, as the developing roller 10 rotates, the toner carried on the developing roller 10 comes into contact with the photosensitive drum 16, and is supplied to the electrostatic latent image formed on the surface of the photosensitive drum 16. In this way, the toner is selectively carried on the surface of the photosensitive drum 16, thereby becoming a visible image, and a toner image is formed by reversal development. Thereafter, the photosensitive drum 16 and the transfer roller 32 are rotated so as to sandwich and transport the paper 3 between them, and the paper 3 is transported between the photosensitive drum 16 and the transfer roller 32. As a result, the toner image carried on the surface of the photosensitive drum 16 is transferred onto the paper 3 .

[0089] <Measurement of surface amino group amount> The proportion of amino groups present on the outermost surface of the developing roller is measured using a time-of-flight secondary ion mass spectrometer (TOF-SIMS). More specifically, this measurement is performed using a time-of-flight secondary ion mass spectrometer (trade name: TRIFT II, manufactured by ULVAC-PHI, Inc.) under the following conditions: Primary ion species: Ga+ Primary ion current (DC): 600pA Primary ion energy: 15kV Sample potential: +3.2 kV Secondary ion detection mode: Positive ·Measurement vacuum degree: 1×10 -7 Pa ·Measurement area: 100μm×100μm Measurement integration time: 300 seconds From the peak intensity of the ions thus obtained, the percentage of the ion intensity derived from amino groups relative to all detected ions is calculated, and this is taken as the proportion of amino groups present on the outermost surface of the developing roller. The discrimination of the fragment derived from the amino group is appropriately selected based on the structure of the acrylic resin estimated by nuclear magnetic resonance (NMR) or the like. Examples of the peaks derived from the amino group include [C2H4N], [C2H5N], [C3H6N], [C3H8N], [C4H 10 N], [C5H 12 N], [C6H 14 N], etc.

[0090] <Measurement of the amounts of Si, F, and Cl surface elements> The abundance ratios of silicon, fluorine, and chlorine on the outermost surface of the developing roller (hereinafter abbreviated as Si / F / Cl amounts) are measured using X-ray photoelectron spectroscopy (XPS). More specifically, this measurement is performed using an X-ray photoelectron spectrometer (trade name: Quantum 2000 Scanning E SCA Microprobe, manufactured by PHI (Physical Electronics I ndustries, INC.) under the following conditions. ·Excitation X-ray: Al Kα ·Photoelectron escape angle: 45° ·X-ray: 100μm 25W 15kV ·Electron neutralization gun: 20μA, 1V ·Ion neutralization gun: 7mA, 10V ·Analysis area: 300μm × 200μm ·Pass Energy: 58.70eV ·Step Size: 0.125eV ·Sweep: F (10 times), C (10 times), O (10 times), Si (30 times), N (30 times), Cl (10 times).

[0091] From the peak intensities of each element obtained, the surface atomic concentration (Atomic%) is calculated using the relative sensitivity factor provided by PHI, and these are taken as the abundance ratios of Si / F / Cl with respect to the constituent elements on the outermost surface of the resin layer.

[0092] <Volume resistivity> The volume resistivity is adopted as the measured value measured using the electric resistance measuring device shown in Fig. 5. A load of 4.9 N is applied to each end of the mandrel of the developing roller 10, and the developing roller 10 is placed in contact with a metal drum 51 having a diameter of 50 mm. The metal drum 51 is rotated at a surface speed of 50 mm / sec, and the developing roller 10 is rotated by the metal drum 51. A resistor R having a known electrical resistance that is two orders of magnitude lower than the electrical resistance of the developing roller 10 is connected between the metal drum 51 and ground (GND). A voltage of +50 V is applied to the mandrel of the developing roller 10 from a high-voltage power supply HV, and the resistor The potential difference between both ends of resistor R is measured using a digital multimeter (e.g., FLUKE 189TRU Measurement is performed using a digital multimeter (Digital Multimeter RMS Multimeter). The current flowing through the metal drum 51 via the developing roller 10 is calculated from the measured value of the potential difference and the electrical resistance of resistor R, and the electrical resistance value of the developing roller 10 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 developing roller. Next, the area of the contact point between the developing roller 10 and the metal drum 51 is calculated. The volume resistivity of the developing roller is calculated from the resistance value of the developing roller, the area of the contact point, and the thickness of the rubber of the developing roller. Specifically, the volume resistivity is calculated using the following formula (1):

number

[0093] <Method for measuring elastic modulus> The elastic modulus of the developing roller in the present disclosure is measured using a scanning probe microscope (SPM). First, the region of the cross-section to be measured of the developing roller is cut out into thin slices using a diamond knife while being held at -110°C with a cryomicrotome (trade name: EMFC6, manufactured by Leica Microsystems, Inc.). Further, a sample with a size of 100 μm square and a depthwise width of 100 μm is created from the thin slice. Here, FIG. 6 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. 6, the region from the outermost surface of the resin layer 12 forming the outermost surface of the developing roller to a depth of 0.1 μm is defined as the first region 61, and the region from the outermost surface to a depth of 1.0 to 1.1 μm is defined as the second region 62. The elastic modulus is measured in each region that appears in the cross-section of the prepared sample. For the measurement, a scanning probe microscope device (trade name: MFP-3D-Origin, manufactured by Oxford Instruments, Inc.) and a probe (trade name: AC160, manufactured by Olympus Corporation) are used. At this time, the force curve is measured 10 times, and the arithmetic mean of 8 points excluding the maximum value and the minimum value is obtained, and the elastic modulus is calculated using the Hertz theory. Let the elastic moduli in the first region 61 and the second region 62 be E1 and E2, respectively.

[0094] <Verification of IPN Structure> The IPN structure of the resin layer was verified using microsampling mass spectrometry. Microsampling mass spectrometry uses an ion trap mass spectrometer. A sample is attached to a filament at the tip of the probe and inserted directly into the ionization chamber. The sample is then rapidly heated from room temperature to 1000°C at a constant heating rate. The heated sample decomposes and vaporizes, ionizing it with an electron beam and detecting it in a mass spectrometer. Under constant heating conditions, a thermal chromatogram similar to TG-MS (thermogravimetric-mass simultaneous analysis) is obtained, with a mass spectrum called a total ion chromatogram (TIC). Furthermore, a thermal chromatogram for a specific mass fragment can be obtained, allowing the peak temperature of the thermal chromatogram to be determined, corresponding to the decomposition temperature of the desired molecular structure. The peak temperature of the thermal chromatogram correlates with the crosslinking structure of the resin; the denser the crosslinking, the higher the peak temperature. In other words, the peak temperature of the thermal chromatogram is higher in the portion where the cross-linked urethane resin and the cross-linked acrylic resin form an IPN structure than in the cross-linked acrylic resin alone.

[0095] A peak top temperature A1 of a thermal chromatogram derived from a crosslinked acrylic resin is obtained from a first sample in the first region. Further, a second peak top temperature A1 obtained by decomposing a crosslinked urethane resin contained in the first sample is obtained. The peak top temperature A2 of the thermal chromatogram derived from the crosslinked acrylic resin measured from the second sample is obtained. The peak top temperatures A1 and A2 of the thermal chromatogram are compared, and if A1 is higher than A2, it means that the crosslinked urethane resin and the crosslinked acrylic resin form an IPN structure. A2 is a value obtained by performing microsampling mass spectrometry on the second sample obtained after decomposing the crosslinked urethane using the pyridine decomposition method described below. Examples of A2 include 390 to 396°C and 391 to 395°C. Examples of A1 include 393 to 398°C and 394 to 397°C.

[0096] <Pyridine decomposition method> The pyridine decomposition method is a method for selectively decomposing urethane bonds. By performing the pyridine decomposition method on a sample that has an IPN structure of cross-linked acrylic resin and cross-linked urethane resin, it is possible to obtain cross-linked acrylic resin after removing the structure derived from the cross-linked 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 cross-linked acrylic resin. Specifically, the pyridine decomposition method is performed as follows. Using a microtome, a 0.1 μm thick sample was cut from the surface of the developing roller, and 500 mg of the sample was collected. 0.5 mL of a 3:1 mixture of pyridine (manufactured by Fujifilm 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 treatment to remove the pyridine. The sample thus obtained was subjected to the microsampling mass spectrometry described above to obtain the A2 value.

[0097] <Structural analysis of cross-linked acrylic resin> The content of amino groups in the crosslinked acrylic resin molecule can be analyzed by known means such as a pyrolysis gas chromatograph mass spectrometer (GC / MS), a Fourier transform infrared spectrophotometer (FT-IR), or a nuclear magnetic resonance spectrometer (NMR). In the present disclosure, the structure derived from the crosslinked urethane was removed by the pyridine method, and the resulting crosslinked acrylic resin was confirmed using FT-IR (product name: FT / IR-4700, manufactured by JASCO Corporation). [Example]

[0098] 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. [Example 1] <1. Manufacturing of developing rollers> In this embodiment, a developing roller in which a resin layer is coated on an elastic roller having an elastic layer on the outer surface of a base body will be described, but the invention is not limited to this configuration.

[0099] [1-1. Preparation of the substrate] As a substrate, a stainless steel (SUS304) core bar having a diameter of 8 mm was prepared, the peripheral surface of which was coated with a primer (product name: DY35-051, manufactured by Dow Toray Co., Ltd.) and baked.

[0100] [1-2. Fabrication of Elastic Layer] The substrate was placed in a mold, and an addition-type silicone rubber composition prepared by mixing the materials shown in Table 1 was poured into the cavity formed in the mold.

[0101] [Table 1]

[0102] The mold was then heated to vulcanize and cure the addition-type silicone rubber composition at 150°C for 15 minutes, and after demolding, the composition was further heated at 180°C for 1 hour to complete the curing reaction, yielding an elastic roller with an elastic layer 20 mm in diameter attached to the outer periphery of the base.

[0103] [1-3. Formation of resin layer] The materials for the resin layer, other than the roughness-forming particles listed in Table 2 below, were stirred and mixed. Then, the materials were dissolved in 2-butanone (MEK, manufactured by Kishida Chemical Co., Ltd.) to a solids concentration of 30% by mass, mixed, and then uniformly dispersed using a sand mill. 2-butanone (MEK) 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 prepare resin layer-forming coating material 1.

[0104] [Table 2]

[0105] Next, the elastic roller was oriented with its longitudinal direction in the vertical direction, and its upper end was gripped and immersed (dipped) in the resin layer-forming coating material 1 to coat the surface of the elastic roller with the coating material. The resulting coating was air-dried at room temperature for 30 minutes, and then dried for 1 hour in a hot air circulating dryer set at 160°C. In this way, a resin layer with a thickness of approximately 15 μm was formed on the elastic layer.

[0106] [1-4. Impregnation treatment] The impregnation and curing treatment of the acrylic monomer was carried out by the following method. The materials shown in Table 3 below were dissolved and mixed to prepare impregnation treatment liquid 1 for the impregnation treatment. The elastic roller on which the resin layer was formed was immersed in this impregnation treatment liquid 1 for 2 seconds to impregnate the acrylic monomer component. After that, 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 By irradiating ultraviolet light so that the acrylic monomer is cured, an IPN structure is formed, and the resulting Roller 1 was produced. A high-pressure mercury lamp (product name: handy type UV curing device, manufactured by Mario Network Co., Ltd.) was used as the ultraviolet ray irradiation device.

[0107] [Table 3]

[0108] <2. Physical property evaluation and analysis> For developing roller 1, volume resistivity measurement, elastic modulus measurement using a scanning probe microscope (SPM), outermost surface amino group amount measurement using a time-of-flight secondary ion mass spectrometer (TOF-SIMS), Si / F / Cl amount measurement using X-ray photoelectron spectroscopy (XPS), and thermal chromatogram peak temperature measurement using microsampling mass spectrometry were carried out. Details of each measurement method are as described above. The physical properties and analytical results of the resulting developing roller 1 are shown in Table 7.

[0109] 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 monochrome laser printer, HL-5440D (manufactured by Brother Industries, Ltd.). The modification involved connecting to an external high-voltage power supply so that an arbitrary potential difference could be established between the toner layer thickness regulating member and the developing roller, and in order to evaluate a high-speed process, the output rate per unit time was set to 50 sheets per minute for A4 size paper. The process cartridge used was a modified version of a commercially available toner cartridge, TN-56J (manufactured by Brother Industries, Ltd.), and the developing roller was replaced with developing roller 1. The cartridge was modified by providing a rotating gear that matched the shape of the developing roller.

[0110] (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 toner layer thickness regulating member and the developing roller to +300V. Under the same conditions, an image of a 4-point "E" letter was continuously printed on an A4 evaluation sheet (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 toner was replenished every 8,000 sheets. This process was repeated until 20,000 sheets were printed, and the fogging value was measured using the following method.

[0111] Using a reflection densitometer (product name: TC-6DS / A, manufactured by Tokyo Denshoku Technology Center Co., Ltd.), the reflection density R1 of the recording material before image formation and the reflection density R2 of the recording material on which a solid white image was printed were measured, and the increase in reflection density (R2-R1) was taken as the "fog value" of the developing roller. The reflection density was measured over the entire image printing area of the recording material, and the arithmetic mean value was used for the recording material before image formation, and the maximum value was used for the recording material on which a solid white image was printed. Next, the arithmetic mean value of the fog values of each image up to 20,000 sheets was calculated. The smaller the fog value, the better, and normally toner is not transferred onto transfer paper on which a solid white image has been formed. When the amount of charge of the toner is insufficient In the case of the above, even when a solid white image is formed, the toner moves onto the photosensitive member and is then transferred onto the transfer paper, increasing the fogging value. The evaluation results are shown in Table 7. Incidentally, since fogging tends to worsen in a high-temperature, high-humidity environment of 30° C. temperature and 80% relative humidity, the evaluation was carried out in the above environment.

[0112] (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 toner layer thickness regulating member and the developing roller was set to +300V, and one solid black halftone image, 48 solid white images, and one solid black halftone image were printed in succession. The densities of the resulting first and 50th halftone images were measured using a spectrodensitometer (product name: 508, manufactured by Xrite Corporation), and the density difference between the first and 50th images was calculated. The smaller the density difference, the better. The evaluation results are shown in Table 7.

[0113] [Examples 2 to 13, Comparative Examples 1 to 7] In Examples 2 to 13 and Comparative Examples 1 to 7, resin layer-forming coating materials 2 to 9 were prepared using the materials and parts shown in Table 4, and impregnation treatment solutions 2 to 11 were prepared using the materials and parts shown in Table 5, using the same method as in Example 1. Developing rollers 2 to 20 were then produced using the combinations shown in Table 6. The resulting developing rollers were subjected to property evaluation, analysis, and image evaluation using the same methods as in Example 1. The evaluation results are shown in Table 7.

[0114] [Table 4] *The materials listed in the table are as follows: "PTGL1000": Product name, manufactured by Hodogaya Chemical Co., Ltd. "PTGL3500": Product name, manufactured by Hodogaya Chemical Co., Ltd. "MR-400 (Millionate MR-400)": Product name, manufactured by Tosoh Corporation "SUNBLACK X15": Product name, manufactured by Asahi Carbon Co., Ltd. "UCN-5090 (Dymic Beads UCN-5090)": Product name, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd. "TSF4445": Product name, polyether-modified silicone oil manufactured by Momentive Performance Materials Japan, LLC. "Surflon S-656": Product name, manufactured by AGC Seimi Chemical Co., Ltd., fluorine-based interface material activator Polyment NK-380: Product name, aminoethylated acrylic polymer manufactured by Nippon Shokubai Co., Ltd.

[0115] [Table 5] *The materials listed in the table are as follows: "EBECRYL7100": Product name, manufactured by Daicel Allnex Co., Ltd. "CN371": Product name, manufactured by Tomoe Engineering Co., Ltd. "EBECRYL80": Product name, manufactured by Daicel Allnex Co., Ltd. "Aron DA": Product name, manufactured by Toagosei Co., Ltd. "EBECRYL145": Product name, manufactured by Daicel Allnex Co., Ltd. "TMPTA": Product name, manufactured by Daicel Allnex Co., Ltd. "Omnirad184": Product name, manufactured by IGM Resins "MEK (2-butanone)": Trade name, manufactured by Kishida Chemical Co., Ltd.

[0116] [Table 6]

[0117] [Table 7]

[0118] Although Examples 1 to 4 differ in the type of aminoacrylic monomer / oligomer used for impregnation, they show good results in the fog evaluation and image density stability evaluation. Example 5, due to the reduced amount of aminoacrylic monomer / oligomer, shows slightly worse results compared to Examples 1 to 4, but still shows good results in the fog evaluation and image density stability evaluation. Example 6, due to the large amount of aminoacrylic monomer / oligomer, shows small fluctuations in the elastic modulus E2, resulting in results comparable to Examples 1 to 4. Examples 7 to 9, due to the use of silicone oil and fluorine-based surfactants, show results that suggest the toner is slightly triboelectrically charged, but still show good results. Examples 10 to 13, due to the lower limits of the hardness (elastic modulus E1), volume resistivity, elastic modulus E2, and elastic modulus E2 of the impregnating agent, respectively, show slightly worse results compared to Examples 1 to 4, but still show good results in the fog evaluation and image density stability evaluation. On the other hand, in Comparative Examples 1 to 7, the process speed is high, and in the configuration with a high blade bias, the results are low in the fogging evaluation and the image density stability evaluation.

[0119] The present disclosure includes the following configurations. (Configuration 1) a conductive substrate; a resin layer present on the outer surface side of the substrate; A developing roller having the developing roller is a developing roller for positively charged toner, the resin layer contains a cross-linked urethane resin, an amino group is present on the outermost surface of the resin layer, When the outermost surface of the resin layer is measured by a time-of-flight secondary ion mass spectrometer (TOF-SIMS), the ion intensity derived from amino groups relative to all detected ions is 1.0% or more. , when the outermost surface of the resin layer is measured by X-ray photoelectron spectroscopy (XPS), the ratio of the total detected values of Si, F, and Cl to the total detected values of F, C, O, Si, N, and Cl is less than 5.0 atomic %; When the elastic modulus in a first region from the outermost surface of the resin layer to a depth of 0.1 μm is defined as E1, E1 is 200 MPa or more, A metal film is provided directly on the outermost surface of the developing 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 A developing roller having a resistivity of Ω·cm or more. (Configuration 2) the resin layer contains a crosslinked acrylic resin, the cross-linked acrylic resin and the cross-linked urethane resin form an interpenetrating polymer network structure; 2. The developing roller according to claim 1. (Configuration 3) 3. The developing roller according to claim 2, wherein the crosslinked acrylic resin has an amino group. (Configuration 4) 4. The developing roller according to any one of configurations 1 to 3, wherein the elastic modulus E2 of the second region from the outermost surface of the resin layer to a depth of 1.0 to 1.1 μm is 1 to 100 MPa. (Configuration 5) 5. The developing roller according to any one of configurations 1 to 4, wherein the outermost surface of the resin layer is the outermost surface of the developing roller. (Configuration 6) A developing cartridge configured to be detachably attached to a main body of an electrophotographic image forming apparatus, The developing cartridge is Toner and a developing roller that carries the toner; a toner layer thickness regulating member that is in contact with the developing roller and that regulates the thickness of the toner layer carried on the developing roller, and to which a predetermined voltage can be applied; and the toner is a positively charged toner having positive charging properties, The developing roller is the developing roller according to any one of configurations 1 to 5. A developing cartridge characterized by: (Configuration 7) the toner contains toner particles and an external additive; The external additive contains inorganic fine particles having amino groups on the surface thereof. 7. The developing cartridge according to claim 6. (Configuration 8) A developing cartridge; an image carrier onto which a toner image is formed by toner supplied from the developing cartridge; A process cartridge having The developing cartridge is the developing cartridge according to configuration 6 or 7. A process cartridge characterized by: (Configuration 9) the toner contains toner particles and an external additive; The external additive contains inorganic fine particles having amino groups on the surface thereof. The process cartridge according to aspect 8. (Configuration 10) An electrophotographic image forming apparatus for forming an image on a recording sheet, The process cartridge according to claim 8 or 9, an exposure device that exposes the image carrier of the process cartridge to light to form an electrostatic latent image on the image carrier; a transfer device that transfers the toner image formed on the image carrier of the process cartridge onto a recording sheet; a fixing device for fixing the toner image transferred onto the recording sheet, Electrophotographic image forming apparatus characterized in that: (Configuration 11) the toner contains toner particles and an external additive; The external additive contains inorganic fine particles having amino groups on the surface thereof. 11. The electrophotographic image forming apparatus according to Configuration 10. (Configuration 12) An electrophotographic image forming apparatus for forming an image on a recording sheet, The electrophotographic image forming apparatus comprises: an image carrier; Toner and a developing roller that carries the toner; a toner layer thickness regulating member that is in contact with the developing roller and that regulates the thickness of the toner layer carried on the developing roller, and to which a predetermined voltage can be applied; an exposure device that exposes the image carrier to light to form an electrostatic latent image on the image carrier; a transfer device that transfers the toner image formed on the image carrier by developing the electrostatic latent image with the toner onto a recording sheet; a fixing device for fixing the toner image transferred onto the recording sheet; and the toner is a positively charged toner having positive charging properties, The developing roller is the developing roller according to any one of configurations 1 to 5. Electrophotographic image forming apparatus characterized in that: (Configuration 13) the toner contains toner particles and an external additive; The external additive contains inorganic fine particles having amino groups on the surface thereof. 13. The electrophotographic image forming apparatus according to claim 12. [Explanation of symbols]

[0120] 2: Main casing 2A: Front cover 3: Paper 4: Paper feed unit 5: Image forming unit 6: Paper feed tray 7: Paper pressure plate 8: Roller 9: Exposure section 10: developing roller 11: substrate 12: resin layer 13: elastic layer 14: Process cartridge 15: Fixing unit 16: Photosensitive drum 17: Heating roller 18: Pressure roller 19: Paper discharge roller 20: Paper output tray 30: Drum cartridge 30A: Drum case 31: Scorotron-type static electricity resister 32: Transfer roller 40: Developer cartridge 41: Development unit 41A: Development case 42: Toner unit 42A: Toner case 43: Toner chamber 44: Toner layer thickness regulating member 45: Supply roller 46: Toner storage chamber 47: Agitator 51: Metal drum 61: First area 62: Second area

Claims

1. a conductive substrate; a resin layer present on the outer surface side of the substrate; A developing roller having the developing roller is a developing roller for positively charged toner, the resin layer contains a cross-linked urethane resin, an amino group is present on the outermost surface of the resin layer, when the outermost surface of the resin layer is measured by a time-of-flight secondary ion mass spectrometer (TOF-SIMS), the ion intensity derived from amino groups relative to all detected ions is 1.0% or more; when the outermost surface of the resin layer is measured by X-ray photoelectron spectroscopy (XPS), the ratio of the total detected values of Si, F, and Cl to the total detected values of F, C, O, Si, N, and Cl is less than 5.0 atomic %; When the elastic modulus E1 in a first region from the outermost surface of the resin layer to a depth of 0.1 μm is defined as E1, E1 is 200 MPa or more, A metal film was directly provided on the outermost surface of the developing roller, and when a DC voltage of 50 V was applied in an environment of a temperature of 23° C. and a relative humidity of 50%, the volume resistivity was 1.0×10 ６ A developing roller having a resistivity of Ω·cm or more.

2. the resin layer contains a crosslinked acrylic resin, the cross-linked acrylic resin and the cross-linked urethane resin form an interpenetrating polymer network structure; 2. The developing roller according to claim 1.

3. 3. The developing roller according to claim 2, wherein the crosslinked acrylic resin has an amino group.

4. 2. The developing roller according to claim 1, wherein the elastic modulus E2 in the second region from the outermost surface of the resin layer to a depth of 1.0 to 1.1 μm is 1 to 100 MPa.

5. 2. The developing roller according to claim 1, wherein the outermost surface of the resin layer is the outermost surface of the developing roller.

6. A developing cartridge configured to be detachably attached to a main body of an electrophotographic image forming apparatus, The developing cartridge is Toner and a developing roller that carries the toner; a toner layer thickness regulating member that is in contact with the developing roller and that regulates the thickness of the toner layer carried on the developing roller, and to which a predetermined voltage can be applied; and the toner is a positively charged toner having positive charging properties, The developing roller is the developing roller according to any one of claims 1 to 5. A developing cartridge characterized by:

7. the toner contains toner particles and an external additive; The external additive contains inorganic fine particles having amino groups on the surface thereof. The developing cartridge according to claim 6.

8. A developing cartridge; an image carrier onto which a toner image is formed by toner supplied from the developing cartridge; A process cartridge having The developing cartridge is the developing cartridge according to claim 6. A process cartridge characterized by:

9. the toner contains toner particles and an external additive; The external additive contains inorganic fine particles having amino groups on the surface thereof. The process cartridge according to claim 8.

10. An electrophotographic image forming apparatus for forming an image on a recording sheet, The process cartridge according to claim 8, an exposure device that exposes the image carrier of the process cartridge to light to form an electrostatic latent image on the image carrier; a transfer device that transfers the toner image formed on the image carrier of the process cartridge onto a recording sheet; a fixing device for fixing the toner image transferred onto the recording sheet, Electrophotographic image forming apparatus characterized in that:

11. the toner contains toner particles and an external additive; The external additive contains inorganic fine particles having amino groups on the surface thereof.

11. The electrophotographic imaging apparatus of claim 10.

12. An electrophotographic image forming apparatus for forming an image on a recording sheet, The electrophotographic image forming apparatus comprises: an image carrier; Toner and a developing roller that carries the toner; a toner layer thickness regulating member that is in contact with the developing roller and that regulates the thickness of the toner layer carried on the developing roller, and to which a predetermined voltage can be applied; an exposure device that exposes the image carrier to light to form an electrostatic latent image on the image carrier; a transfer device that transfers the toner image formed on the image carrier by developing the electrostatic latent image with the toner onto a recording sheet; a fixing device for fixing the toner image transferred onto the recording sheet; and the toner is a positively charged toner having positive charging properties, The developing roller is the developing roller according to any one of claims 1 to 5. Electrophotographic image forming apparatus characterized in that:

13. the toner contains toner particles and an external additive; The external additive contains inorganic fine particles having amino groups on the surface thereof.

13. The electrophotographic imaging apparatus of claim 12.

Images