Process cartridge, and electro-photographic image formation device

Abstract

To suppress occurrence of fogging in a high temperature and high humidity environment and roughness in a low temperature and low humidity environment, through an endurance use in a system in which a processing speed is fast.SOLUTION: A process cartridge has: developer; a developer carrier; and a developer layer thickness restriction member of which at least a part restricts a layer thickness of the developer to be carried on the developer carrier. The process cartridge is detachably attached to a main body of an electro-photographic image formation device, and the developer carrier has: a substrate; and a resin layer that exists on an outermost surface side of the substrate. A metal film is directly provided on an outer surface of the developer carrier, and measured impedance is equal to or more than 1.00*106 Ω, and let ionization potential of the developer be I(T), and ionization potential of the outer surface of the developer carrier be I(R), the I(T) and I(R) satisfy a specific relationship, and a maximum value of electric potential when measuring the outer surface of the developer carrier is less than 20.0 V.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] There is a need for even faster process speeds for electrophotographic image forming devices, compatibility with a variety of media, and environmental compatibility. To address these needs, the method of imparting charge to the developer is being changed from the conventional frictional charging method to an injection charging method. The injection charging method applies a high voltage to a developer layer thickness regulating member in contact with the developer carrier, thereby more quickly imparting charge to the developer. The charge injected into the developer from the developer layer thickness regulating member can be controlled by the voltage of the developer layer thickness regulating member, which is expected to reduce the effects of environmental factors such as temperature and humidity. Furthermore, by increasing the voltage of the developer layer thickness regulating member, it is expected that an appropriate charge will be imparted to the developer even when the process speed is increased.

[0003] Patent Document 1 discloses a configuration for reducing the difference in the triboelectric series between the developer, the developer layer thickness regulating member, and the developer carrier in a process cartridge capable of applying a voltage to the developer layer thickness regulating member. According to this document, under certain conditions, it is possible to impart a charge to the developer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 3-233479 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the present inventors recognized that when an electrophotographic image forming apparatus with a high process speed according to the configuration of Patent Document 1 is used in a high-temperature, high-humidity environment or a low-temperature, low-humidity environment, fog may occur and the amount of charge imparted to the developer may fluctuate. Specifically, fog may occur more easily in a high-temperature, high-humidity environment, and a decrease in dot reproducibility in a low-temperature, low-humidity environment may appear as roughness. The present disclosure is directed to providing a process cartridge and an electrophotographic image forming apparatus that can suppress the occurrence of fogging in high-temperature, high-humidity environments and roughness (reduced dot reproducibility) in low-temperature, low-humidity environments through durable use in systems with high process speeds. [Means for solving the problem]

[0006] The present disclosure provides a developer carrier, a developer layer thickness regulating member, at least a part of which is conductive, that contacts the developer carrier and regulates the layer thickness of the developer carried on the developer carrier; a contact point electrically connected to the developer layer thickness regulating member; a developer accommodating member that accommodates the developer, the contact is electrically connected to a contact of the main body of the electrophotographic image forming apparatus when the process cartridge is mounted in the main body of the electrophotographic image forming apparatus, thereby enabling a predetermined voltage to be applied to the developer layer thickness regulating member, the developer carrier comprises a substrate having an electrically conductive outer surface; a resin layer present on the outer surface side of the substrate, A metal film was provided directly on the outer surface of the developer carrier, and a DC voltage of 50 V was applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%. AC voltage with a frequency of 1.0 x 10 -1 ~1.0×10 5 When applied while changing between Hz, the frequency is 1.0 × 10 0 ~1.0×10 1 Impedance at Hz is 1.00 x 10 6 is greater than or equal to Ω, When the ionization potential of the developer is I(T) and the ionization potential of the outer surface of the developer carrier is I(R), The I(T) and the I(R) satisfy the following formula (X): │I(T)-I(R)│≦0.3eV ···(X) This process cartridge is configured such that, in an environment of a temperature of 23°C and a relative humidity of 50%, a corona discharger having a grid portion with a width of 3.0 mm is disposed such that the distance between the grid portion and the outer surface of the developer carrier is 1.0 mm and the direction of the width of the grid portion coincides with the axial direction of the developer carrier, a voltage of 8 kV is applied to the grid portion, and the corona discharger is moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier, and the maximum value of the potential of the outer surface measured 0.06 seconds after the grid portion has passed is less than 20.0 V.

[0007] The present disclosure provides an electrophotographic image forming apparatus equipped with a detachable process cartridge, The present invention relates to an electrophotographic image forming apparatus in which the process cartridge is the above-mentioned process cartridge. [Effects of the Invention]

[0008] According to the present disclosure, a process cartridge and an electrophotographic image forming apparatus can be provided that can suppress the occurrence of fogging in high-temperature, high-humidity environments and roughness (deterioration of dot reproducibility) in low-temperature, low-humidity environments through durable use in systems with high process speeds. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic cross-sectional view showing an example of a developer carrier. [Figure 2] FIG. 4 is a schematic cross-sectional view showing another example of a developer carrier. [Figure 3] FIG. 2 is a schematic diagram of a process cartridge. [Figure 4] FIG. 1 is a schematic diagram of an electrophotographic image forming apparatus. [Figure 5]FIG. 2 is a schematic diagram showing a state in which measurement electrodes are formed on a developer carrier. [Figure 6] FIG. 2 is a cross-sectional view of a developer carrier and a measurement electrode. [Figure 7] FIG. 1 is a schematic diagram of an impedance measurement system. [Figure 8] FIG. 2 is a schematic diagram showing an example of an apparatus for measuring the surface potential of a developer carrier. [Figure 9] FIG. 10 is a schematic diagram of a circuit for measuring a leakage current flowing from a developer to a developer carrier. [Figure 10] FIG. 1 is a schematic diagram of an electrophotographic image forming apparatus for image evaluation. [Figure 11] This is an example of the results obtained by ionization potential measurement. [Figure 12] FIG. 2 is a cross-sectional view of a developer carrier. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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.

[0011] The present inventors have studied a configuration capable of suppressing the occurrence of fogging in a high-temperature, high-humidity environment and roughness in a low-temperature, low-humidity environment through durable use in a system with a high process speed. It has been found that the injection charging method, which applies a charge to a developer by friction between the developer layer thickness regulating member and the developer carrier, is more important in satisfying the following requirements than the friction charging method, which charges the developer by friction between the developer layer thickness regulating member and the developer carrier. Requirement (1) A mechanism that can apply a voltage to the developer layer thickness regulating member and inject a charge into the developer. Item (2) A developer carrier that does not allow the charge injected into the developer to leak to the developer carrier. Item (3) A developer carrier that allows the excess charge that has built up on the surface of the developer carrier to leak.

[0012] By satisfying the above items (1) to (3), the amount of charge injected into the developer can be controlled to a constant level in both high-temperature and high-humidity environments and low-temperature and low-humidity environments. Furthermore, by satisfying the following item (4), it is possible to obtain a very uniform, high-quality image with high dot reproducibility and little roughness. Item (4) By aligning the charge series of the developer and the developer carrier, charge imparted to the developer due to frictional charging is suppressed. The above items (1) to (4) will be explained below.

[0013] First, when applying charge to the developer by the injection charging method, the above items (1) and (4) are necessary. According to item (1), a voltage is applied to the developer layer thickness regulating member, and when the developer comes into contact with the member, a charge is injected into the developer. a developer carrier; a developer layer thickness regulating member that contacts the developer carrier and regulates the layer thickness of the developer carried on the developer carrier; a contact point electrically connected to the developer layer thickness regulating member; a developer containing member that contains the developer; This can be achieved by a process cartridge having the above structure.

[0014] By satisfying item (4), it is possible to suppress the degree of charge imparted to the developer due to friction between the developer and the developer carrier. It is generally known that charge generated by frictional charging is easily affected by the surrounding environment. Specifically, when comparing charge generated by frictional charging in a normal temperature and humidity environment with charge generated in a low temperature and humidity environment, the developer will acquire more charge in the latter. Furthermore, because the amount of friction varies depending on the frequency of contact between the developer carrier and the developer, the charge amount per particle of the developer exhibits a broad range of charge characteristics, with some developers having a high charge amount and others having a low charge amount. The present disclosure is characterized by reducing the charge amount of the developer generated by frictional charging and increasing the charge amount of the developer generated by injection charging, which will be described later.

[0015] Regarding item (4), in this disclosure, the triboelectric series of a developer or developer carrier is expressed in terms of ionization potential. Ionization potential is a physical property that indicates the degree to which an electric charge is released. When two substances with different ionization potentials come into contact and are rubbed, an electric charge moves from the substance with the lower ionization potential to the substance with the higher ionization potential. As a result, the substance with the lower ionization potential becomes positively charged, and conversely, the substance with the higher ionization potential becomes negatively charged.

[0016] In the present disclosure, when the ionization potential of the developer is I(T) and the ionization potential of the outer surface of the developer carrier is I(R), I(T) and I(R) satisfy the following formula (X): │I(T)-I(R)│≦0.3eV ···(X)

[0017] Formula (X) shows that the charge series (ionization potential) of the developer and the developer carrier are close to each other. By satisfying this, when the developer carrier and the developer are rubbed against each other, The charge imparted to the developer by frictional charging can be suppressed, thereby suppressing roughness. The method for controlling the ionization potential of the developer and the developer carrier and the method for measuring the ionization potential will be described later.

[0018] By satisfying item (2), when charge is injected into the developer from the developer layer thickness regulating member to which a voltage is applied, leakage of the charge of the developer to the developer carrier can be suppressed. That is, with regard to item (2), a metal film is provided directly on the outer surface of the developer carrier, and a DC voltage of 50 V is applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23°C and a relative humidity of 50%, while an AC voltage of 50 V amplitude and a frequency of 1.0 × 10 -1 ~1.0×10 5 When applied while changing between Hz, the frequency is 1.0 × 10 0 ~1.0×10 1 Impedance at Hz is 1.00 x 10 6 It is greater than or equal to Ω.

[0019] This impedance is a physical property that indicates the charge leakage from the developer to the developer carrier. According to the study by the present inventors, the current value (leakage current value) flowing through the developer carrier when a blade bias is applied to the developer layer thickness regulating member was measured according to the circuit diagram shown in Figure 9. As a result, it was found that this current value shows a higher correlation with the impedance value of the developer carrier than with the electrical resistance value of the developer carrier. This shows that charge leakage requires consideration of the effects of not only the resistance component of the developer carrier but also the capacitance component. This is thought to be because, when the electrical characteristics of the developer carrier are simulated using an RC parallel circuit, the transient state until a sufficient amount of charge accumulates in the capacitance component and the steady state dominated by the resistance component has a large effect on charge leakage.

[0020] The voltage application conditions for impedance measurement were a DC voltage of 50 V superimposed with an AC voltage of 50 V. That is, a sine wave with minimum and maximum applied voltages of 0 V and 100 V (Vpp 100 V) was applied. This value of Vpp 100 V is an assumed maximum value of the shared voltage applied to the developer carrier when a voltage is applied in an electrophotographic image forming apparatus so that a voltage difference of 300 V is applied between the developer carrier and the developer layer thickness regulating member.

[0021] Impedance exhibits bias dependency, meaning that impedance decreases as the bias increases, but it is known that the degree of this decrease varies depending on the developer carrier. Conventional impedance measurements of developer carriers generally use an AC voltage of 1 V. However, this AC voltage is clearly smaller than the voltage (generally several hundred volts) applied between the developer carrier and the developer layer thickness regulating member in an actual electrophotographic image forming apparatus. Therefore, it often fails to simulate the behavior of the developer carrier in an electrophotographic image forming apparatus, and is therefore often inappropriate as an impedance measurement condition. Therefore, in this disclosure, voltage application conditions that mimic the high blade bias applied to an actual electrophotographic image forming apparatus are adopted. Also, a sine wave with a minimum applied voltage of 0 V mimics a square wave that is generally used in applying a blade bias to an actual electrophotographic image forming apparatus.

[0022] In this disclosure, the frequency 1.0×10 0 ~1.0×10 1 The impedance is specified at a frequency of 1.0 x 10 0 ~1.0×10 1 The low frequency range of 1.0 x 10 Hz is the region where the transient state is completed and the steady state dominated by the resistance component is reached. In other words, the influence of both the capacitance component and the resistance component is reflected, and this region is suitable for understanding the charge leakage from the developer to the developer carrier. 0 ~1.0×10 1 Impedance at Hz is 1.00×10 6 When the resistance is Ω or more, the charge leakage is low, and under a high blade bias, charge leakage from the developer to the developer carrier is suppressed, and a decrease in the charge amount of the developer can be prevented.

[0023] Item (3) is related to the surface potential of the developer carrier and indicates the characteristic of attenuating excess charge that has built up on the surface of the developer carrier. In this disclosure, charge is injected into the developer by the voltage difference applied between the developer layer thickness regulating member and the developer carrier. If excess charge remains on the surface of the developer carrier, the voltage difference decreases, reducing the amount of charge that can be injected into the developer. In order to keep the amount of charge injected into the developer constant, the surface of the developer carrier is given an attenuation characteristic.

[0024] As item (3), the decay characteristics of the developer carrier surface are defined as follows: In this disclosure, a voltage of 8 kV is applied to the grid portion, and a corona discharger is moved relatively along the axial direction of the developer carrier at a speed of 400 mm / s. At this time, the potential of the outer surface of the developer carrier is confirmed 0.06 seconds after the grid portion of the corona discharger passes. If the maximum value of the surface potential of the outer surface is less than 20.0 V, the occurrence of image defects due to excessive charging of the developer can be suppressed even in electrophotographic image forming devices with high process speeds, in which the time it takes for the developer charged by the developer layer thickness regulating member to be transported to the photoconductor is shorter. Note that the time 0.06 seconds after the grid portion of the corona discharger passes simulates a model with a high process speed.

[0025] By satisfying the above items (2) and (3), it is possible to solve the conflicting problems of preventing charge leakage from the developer to the developer carrier and removing charge that has built up on the surface of the developer carrier at a high level, thereby suppressing the occurrence of fogging in a high-temperature, high-humidity environment and roughness in a low-temperature, low-humidity environment.

[0026] By combining the above items (1) to (4), the charge of the developer can be suppressed by frictional charging and at the same time, the charge of the developer can be increased by injection charging. Furthermore, it is possible to control the charge of the developer obtained by injection charging at a constant level.

[0027] This makes it possible to obtain high-quality images with less roughness throughout the life of the device by making the charge distribution of the developer uniform.Furthermore, even in electrophotographic image forming apparatuses with increased process speed, it is possible to obtain high-quality images with less fogging and roughness throughout the life of the device in both high-temperature, high-humidity and low-temperature, low-humidity environments.

[0028] Regarding item (4), if formula (X) is not satisfied, the influence of charge imparted to the developer due to frictional charging increases. This may result in degradation of image quality, such as roughness. |I(T)-I(R)| is, for example, 0 to 0.3, preferably 0 to 0.2, and more preferably 0 to 0.1.

[0029] Regarding item (2), the impedance of the developer carrier is 1.00×10 6 If the impedance is less than Ω, the charge of the developer tends to leak onto the developer carrier. Therefore, there is a possibility that fogging in a high-temperature, high-humidity environment cannot be suppressed. The impedance is preferably 1.00×10 6 Ω or more 5.00×10 7 Ω or less, preferably 2.00×10 6 Ω or more 5.00×10 7 Ω or less, more preferably 7.00 × 10 6 Ω or more 5.00×10 7 Ω or less, and even more preferably 7.00×10 6 Ω or more 2.00×10 7 It is less than Ω.

[0030] Regarding item (3), when the surface potential of the developer carrier is 20.0 V or higher, the potential difference between the developer layer thickness regulating member and the developer carrier is likely to decrease due to the influence of the charge accumulated on the surface of the developer carrier. As a result, the charge of the developer decreases during continuous printing, which tends to result in fogging and deterioration of image quality. The lower the surface potential of the developer carrier, the better, and there is no particular lower limit. The preferred range of the surface potential of the developer carrier is, for example, 0 V or higher but less than 20.0 V, particularly 0 V or higher but 10.0 V or lower, and even more preferably 0 V or higher but 7.0 V or lower.

[0031] The present disclosure will be described in detail below. <Developer Carrier> A developer carrier according to at least one embodiment of the present disclosure includes a substrate having a conductive outer surface, and a resin layer present on the outer surface side of the substrate. An example of a developer carrier is shown in Fig. 1. The developer carrier 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 developer carrier 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 developer carrier is a developer carrier having an elastic layer 13 as an intermediate layer between the substrate 11 and the resin layer 12 provided on the outer peripheral surface thereof, as shown in Fig. 2. The resin layer 12 is, for example, a surface layer. It is preferable that the resin layer 12 forms the outer surface of the developer carrier.

[0032] [Base] The substrate has a conductive outer surface and functions as a support member for the developer carrier, and in some cases as an electrode. Specific examples of the substrate preferably have a solid columnar or hollow cylindrical shape.

[0033] The material for the substrate can be appropriately selected from those known in the field of electroconductive members for electrophotography and materials usable as such developer carriers, and examples thereof include metals or alloys such as aluminum and stainless steel, carbon steel alloys, conductive synthetic resins, iron, and copper alloys.

[0034] Furthermore, the material constituting the substrate may be subjected to an oxidation treatment or a plating treatment with chromium, nickel, or the like. Either electroplating or electroless plating can be used as the type of plating. Electroless plating is preferred from the viewpoint of dimensional stability. Examples of electroless plating that can be used here include nickel plating, copper plating, gold plating, and various other alloy platings. The plating thickness is preferably 0.05 μm or more, and considering the balance between work efficiency and rust prevention ability, the plating thickness is preferably 0.1 to 30 μm.

[0035] A primer may be applied to the surface of the substrate to improve adhesion between the substrate and the resin layer. A known primer can be selected and used depending on the rubber material for forming the conductive layer and the material of the support. Examples of primer materials include thermosetting resins and thermoplastic resins. Specific examples of materials that can be used include phenolic resins, polyurethanes, acrylic resins, polyester resins, polyether resins, and epoxy resins.

[0036] [Resin layer] (binder resin) The developer carrier has a resin layer on the outer surface of a substrate. For example, the resin layer is present on the outer surface of the developer carrier. The resin layer may contain a binder resin. Known materials can be used as the binder resin for the resin layer. The resin layer may contain a binder resin. The binder resin for the resin layer is preferably a urethane resin, more preferably a cross-linked urethane resin. The urethane resin (preferably a cross-linked urethane resin) is preferably a polyurethane having a polycarbonate structure in order to suppress charge leakage from the developer to the developer carrier. That is, the resin layer preferably contains a polyurethane having a polycarbonate structure. The polyurethane having a polycarbonate structure is more preferably a cross-linked urethane resin. Furthermore, in order to suppress charge leakage from the developer to the developer carrier while maintaining a light load on the developer and sufficient wear resistance of the resin layer, it is more preferable to use a polyurethane having the structure described below as the binder resin for the resin layer.

[0037] The polyurethane having a polycarbonate structure preferably satisfies at least two of the following (A), (B), and (C), and may also satisfy all of the following (A), (B), and (C). (A) The polyurethane has a structure represented by the following structural formula (1) in its molecule; (B) The polyurethane has at least one structure selected from the group consisting of a structure represented by the following structural formula (2) and a structure represented by the following structural formula (3) in the molecule: (C) The polyurethane has a structure represented by the following structural formula (4) in the molecule.

[0038] That is, it is preferable that the polyurethane satisfies at least one of the following requirements. -Having at least a structure represented by structural formula (1) and a structure represented by structural formula (2) ·Having at least a structure represented by structural formula (1) and a structure represented by structural formula (3) ·Having at least a structure represented by structural formula (1) and a structure represented by structural formula (4) ·Having at least a structure represented by structural formula (2) and a structure represented by structural formula (4) ·Having at least a structure represented by structural formula (3) and a structure represented by structural formula (4) In particular, from the viewpoint of better suppression of fogging and roughness, it is more preferable that the polyurethane has at least the structure represented by structural formula (1) and the structure represented by structural formula (2) in the molecule. [ka]

[0039] In structural formula (1), R11, R12, and R13 represent divalent hydrocarbon groups having 3 to 9 carbon atoms, provided that R11 and R12 are different from each other, and R13 is the same as at least one selected from the group consisting of R11 and R12. m and n are the average number of moles added, and are respectively Each independently represents a number of 1.0 or more (preferably 1.0 to 20.0, more preferably 2.0 to 12.0). In structural formula (2), o and p are the average number of moles added, and each independently represents a number of 1.0 or more (preferably 1.0 to 15.0, more preferably 4.0 to 10.0). In structural formula (3), R31 and R32 each independently represent a divalent hydrocarbon group having 3 to 8 carbon atoms. q and r each independently represent the average number of moles added and are 1.0 or greater (preferably 1.0 to 20.0, more preferably 2.0 to 14.0). In structural formula (4), R41 represents a divalent hydrocarbon group having 6 to 9 carbon atoms (preferably 5 to 8). s represents the average number of moles added and is a number of 1.0 or more (preferably 1.0 to 22.0, more preferably 4.0 to 18.0).

[0040] The structure shown in structural formula (1) is a copolymer polycarbonate polyol in which crystallinity is suppressed by linking two carbonate groups with two different hydrocarbon groups, and the polyol is reacted with isocyanate. Because the crystallinity is suppressed, the cohesive energy in the soft segments is small, which gives the resin layer flexibility and high volume resistivity.

[0041] By using the structure of structural formula (1) in combination with the structures (2) to (4) described above in the resin layer, the adhesiveness of the resin layer can be reduced, which prevents the developer, powder, etc. from adhering to the surface of the resin layer, suppresses an increase in the electrical resistance of the surface of the resin layer due to contamination, and facilitates uniform charging of the developer.

[0042] In structural formula (1), R11 and R12 are each independently a divalent hydrocarbon group having 3 to 9 carbon atoms. R11 and R12 are different from each other, and R13 is the same as at least one selected from the group consisting of R11 and R12. If the number of carbon atoms in R11 and R12 is 3 or more, the amount of carbonate groups, which are polar functional groups with strong cohesive energy, in the polyurethane having a polycarbonate structure will not be too large, making it easier to maintain the resin layer flexible and with a high electrical resistance. Furthermore, when the carbon numbers of R11 and R12 are 9 or less, the amount of carbonate groups in the polyurethane is not too small, and the strength of the polymer can be maintained. Furthermore, when R11 and R12 have different structures, the crystallinity of the polymer can be suppressed and flexibility can be imparted to the resin layer. m and n each independently represent a number of 1.0 or more. The hydrocarbon groups represented by R11, R12, and R13 may have a branched structure or a cyclic structure.

[0043] The structures shown in structural formulas (2) and (3) are obtained by reacting a copolymer polyol, which is a copolymer of a polycarbonate structure and a polyester structure, with an isocyanate. By copolymerizing a polycarbonate structure and a polyester structure, the crystallinity of the polymer is suppressed, and by introducing an ester group, which has a stronger cohesive energy than a carbonate group, the soft segment is appropriately reinforced, thereby imparting abrasion resistance to the resin layer. When a resin layer is formed using a polymer in which the structure represented by structural formula (2) and / or structural formula (3) is combined with the structure represented by formula (1) or (4), the resin layer can be given sufficient volume resistivity while having a polar ester group, making it easier to suppress charge leakage from the developer to the developer carrier.

[0044] In structural formula (2), o and p each independently represent a number of 1.0 or more. In structural formula (3), R31 and R32 each independently represent a divalent hydrocarbon group having 3 to 8 carbon atoms, and q and r each independently represent a number greater than or equal to 1.0. When R31 and R32 each have 3 or more carbon atoms, the amount of carbonate groups and ester groups in the polyurethane, which are polar functional groups with strong cohesive energy, is not too large, thereby maintaining flexibility of the resin layer. When R31 and R32 each have 8 or less carbon atoms, the amount of carbonate groups and ester groups in the polyurethane is not too small, thereby providing abrasion resistance to the resin layer.

[0045] The structure shown in structural formula (4) is a structure obtained by reacting a highly crystalline polycarbonate polyol, in which two carbonate groups are bonded by a single hydrocarbon group, with an isocyanate. This structure is highly crystalline and easily oriented in the soft segment, imparting abrasion resistance and high volume resistivity to the resin layer. By forming a resin layer using a polymer that combines the structure shown in structural formula (4) with the structures of formulas (1) to (3) described above, the hardness of the resin layer is not excessively high and can be easily controlled appropriately.

[0046] In structural formula (4), R41 represents a divalent hydrocarbon group having 6 to 9 carbon atoms, and s represents a number of 1.0 or more. When R41 has 6 or more carbon atoms, crystallinity is easily exhibited, and the resin layer can be imparted with abrasion resistance and high volume resistivity. When R41 has 9 or less carbon atoms, excessive crystallinity can be suppressed, and therefore, by further containing at least one of the structures represented by structural formulas (1), (2), and (3) in the polymer, an increase in the hardness of the resin layer can be suppressed.

[0047] The resin layer preferably contains a polymer having a urethane bond, i.e., a polyurethane having a polycarbonate structure, as a binder resin, and the polymer preferably satisfies at least two selected from the group consisting of (A), (B), and (C) above, which makes the resin layer flexible and less susceptible to wear.

[0048] The structure of the polymer contained in the resin layer of the developer-carrying member can be confirmed by, for example, pyrolysis GC / MS, FT-IR, or NMR analysis.

[0049] Polyurethanes having a polycarbonate structure can be produced using (A) a polyol compound and (B) a polyisocyanate compound. Polyurethanes are usually synthesized by the following methods (1) and (2). (1) A one-shot method in which a polyol component and a polyisocyanate component are mixed and reacted, and (2) a method in which an isocyanate-terminated prepolymer obtained by reacting a portion of a polyol with an isocyanate is reacted with a chain extender such as a low-molecular-weight diol or low-molecular-weight triol.

[0050] In the present disclosure, polyurethane may be synthesized by any of the above methods. A method of subjecting a hydroxyl-terminated prepolymer obtained by reacting a raw material polyol with an isocyanate to a thermal curing reaction with an isocyanate-terminated prepolymer obtained by reacting a raw material polyol with an isocyanate is more preferred. The polyurethane having a polycarbonate structure is preferably a reaction product of a mixture containing a hydroxyl-terminated prepolymer and an isocyanate-terminated prepolymer. The mixture can be used as a coating liquid for forming a resin layer. The polyurethane having a polycarbonate structure is more preferably a reaction product of a mixture containing a hydroxyl-terminated prepolymer, an isocyanate-terminated prepolymer, a conductive filler, and an additive.

[0051] When there are many hydroxyl groups, isocyanate groups, or urea bonds, allophanate bonds, isocyanurate bonds, etc., many polar functional groups are present in the polyurethane, which increases the water absorption of the polymer and reduces the volume resistivity of the resin layer, potentially leading to charge leakage from the developer to the developer carrier. On the other hand, by thermally curing the hydroxyl-terminated prepolymer and the isocyanate-terminated prepolymer, it is possible to obtain a polyurethane with little unreacted polyol or polar functional groups without using an excessive amount of isocyanate.

[0052] (A) Polyol compound As the polyol compound, polyols known for or usable for synthesizing urethane resins can be used. Examples of polyol compounds include polycarbonate polyols, polyether polyols, Polyester polyols, polyolefin polyols such as polybutadiene polyols and polyisoprene polyols, so-called polymer polyols obtained by polymerizing ethylenically unsaturated monomers in polyols, polyester polycarbonate copolymer polyols, and the like. Among these, polycarbonate polyols and polyester polycarbonate copolymer polyols are preferred.

[0053] 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.

[0054] 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.

[0055] (B) Polyisocyanate compound The polyisocyanate may be selected from commonly used and known polyisocyanates, such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymeric diphenylmethane polyisocyanate, hydrogenated MDI, polymeric MDI, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPDI). Among these, aromatic isocyanates such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymeric diphenylmethane polyisocyanate, and polymeric MDI are more preferably used. Other polyisocyanates may also be used as long as they do not affect the impedance value and surface potential.

[0056] The ratio of the number of isocyanate groups to the number of hydroxyl groups (hereinafter also referred to as "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 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 can be reduced.

[0057] Regardless of which material is used, a urethane resin can be obtained by reacting a polyol with an isocyanate under heating. Furthermore, if either or both of the polyol and isocyanate have a branched structure and three or more functional groups, the resulting urethane resin will be a crosslinked urethane resin.

[0058] In the present disclosure, the elastic modulus E1 in a region from the outer surface of the developer carrier to a depth of 0.1 μm, measured in a cross section in the thickness direction of the resin layer of the developer carrier, is preferably 200 MPa or more.

[0059] This elastic modulus E1 indicates that the surface of the developer carrier is relatively hard. When the developer is pressed against the developer carrier by the developer layer thickness regulating member, the developer layer thickness regulating member is hard. Furthermore, the contact area between the developer and the developer carrier can be reduced, which reduces the chance of frictional charging between the developer carrier and the developer, and further prevents the charge of the developer from leaking to the developer carrier.

[0060] The elastic modulus E1 is preferably 200 to 700 MPa, and more preferably 300 to 600 MPa. As a means for controlling the above-mentioned elastic modulus E1 within a desired range, in view of achieving compatibility with item (3), it is preferable to form the following interpenetrating polymer network structure (IPN structure) on the surface of the developer carrier.

[0061] As described above, the binder resin of the resin layer is preferably a urethane resin, more preferably a cross-linked urethane resin. Cross-linked urethane resins are excellent in flexibility and strength, and can form an interpenetrating polymer network structure (IPN structure) described below, making them suitable as binders. The cross-linked urethane resin is preferably, for example, polyurethane having the above-mentioned polycarbonate structure.

[0062] The elastic modulus E2 in a region at a depth of 1.0 to 1.1 μm from the outer surface of the developer carrier, measured in a cross section in the thickness direction of the resin layer of the electrophotographic roller, is, for example, 1 to 150 MPa, preferably 1 to 100 MPa, more preferably 10 to 100 MPa, and even more preferably 30 to 70 MPa.

[0063] When E2 is within the above range, even when the developer is pressed against the developer carrier by the developer layer thickness regulating member, excessive stress is not applied to the developer, and cracking of the developer can be suppressed. This is preferable because it allows for obtaining high-quality images even in higher durability evaluations. From the viewpoint of selectively increasing E1 without increasing E2, it is preferable to form the following interpenetrating polymer network structure (IPN structure) on the surface of the developer carrier.

[0064] (surface modifier) The ionization potential I(R) of the outer surface of the developer-carrying member is preferably 4.0 to 5.8 eV, and more preferably 4.5 to 5.6 eV. A method for controlling the ionization potential of the surface of the developer carrier within a desired range will now be described. A means for increasing the ionization potential of the surface of the developer-carrying member is to have a large amount of silicon- and / or fluorine-containing materials on the surface of the developer-carrying member, while a means for decreasing the surface ionization potential is to have a large amount of amino-group-containing materials on the surface of the developer-carrying member.

[0065] As a specific means for increasing the ionization potential of the surface of the developer-carrying member, it is preferable to use a surface modifier containing silicon and / or fluorine in the resin layer of the developer-carrying member. The surface modifier is preferably a (meth)acrylate monomer and / or oligomer having at least one or both of a silicone group and a fluorine group in the molecule. That is, it is preferable that the resin layer (preferably a crosslinked acrylic resin) contains at least one group selected from the group consisting of a silicone group and a fluorine group in the molecule.

[0066] By using these, it becomes easy to control the ionization potential of the surface of the developer carrier within the range of 4.6 to 5.6 eV. As the type of acrylate monomer or oligomer used here, a polyfunctional monomer or polyfunctional oligomer having a plurality of acryloyl groups or methacryloyl groups as functional groups is preferred in order to facilitate incorporation into the IPN structure.

[0067] The (meth)acrylate monomer or oligomer having a silicone group in the molecule is specifically Specifically, it is a (meth)acrylate monomer or oligomer having the structure of the following formula (1): The silicone group preferably has a siloxane structure, more preferably has the structure of the following formula (1). [ka]

[0068] In formula (1), R 1 ,R 2 are each independently H or a hydrocarbon group having 1 to 4 carbon atoms (for example, an alkyl group). Examples of the (meth)acrylate monomer or oligomer having a silicone group in the molecule include silicone (meth)acrylates such as silicone di(meth)acrylate and silicone hexa(meth)acrylate; and trifunctional alkylalkoxysilanes such as 3-methacryloxypropyltrimethoxysilane.

[0069] Specifically, the (meth)acrylate monomer or oligomer having a fluorine group in the molecule is a (meth)acrylate monomer or oligomer having the structure of the following formula (2). For example, a fluorine-modified acrylate can be used. (Meth)acrylic acid alkyl ester in which at least a portion of the alkyl group is substituted with fluorine can be used. [ka] In equation (2), R 1 ,R 2 R each independently represents F or a hydrocarbon group having 1 to 4 carbon atoms (for example, an alkyl group). 1 ,R 2 At least one of the above indicates F.

[0070] Specifically, the (meth)acrylate monomer or oligomer having a silicone group and a fluorine group in the molecule is a (meth)acrylate monomer or oligomer represented by the formula (1) above, 1 ,R 2 At least one of the above is a (meth)acrylate monomer or oligomer having a structure in which the monomer or oligomer is a fluoroalkyl group (having 1 to 4 carbon atoms). For example, fluorine / acrylic-modified organopolysiloxane can be mentioned.

[0071] From the viewpoint of surface orientation and compatibility when the surface modifier is mixed with the raw material of the urethane resin binder resin, the weight-average molecular weight (Mw) of the surface modifier is preferably 200 to 3000. A weight-average molecular weight of 200 or more facilitates phase separation and surface orientation during the coating and curing process of the resin layer. Furthermore, a weight-average molecular weight of 3000 or less facilitates compatibility of the surface modifier. A weight-average molecular weight of 3000 or less can prevent the surface modifier from seeping out onto the surface of the developer carrier. Therefore, the surface modifier can be prevented from forming an insulating film on the surface of the electrophotographic roller, making it easy to maintain a low surface potential.

[0072] The amount of the surface modifier to be added is preferably 1.0 to 5.0 parts by mass with respect to 100 parts by mass of the resin that constitutes the resin layer.

[0073] A specific means for lowering the ionization potential of the surface of the developer-carrying member is to have a large amount of a material containing an amino group present on the surface of the developer-carrying member. It is preferable to use a material containing an amino group as a surface modifier. Specifically, it is preferable to use an acrylic monomer and / or oligomer containing an amino group as a surface modifier in the resin layer of the developer-carrying member. By using these, it becomes easier to control the ionization potential of the surface of the developer-carrying member within the range of 4.0 to 4.6 eV. For example, amino(meth)acrylate can be mentioned. The type of acrylate monomer or oligomer used here is preferably a polyfunctional monomer or oligomer having a plurality of acryloyl groups or methacryloyl groups as functional groups, in order to facilitate incorporation into the IPN structure. The preferred number of parts added and the range of the weight average molecular weight (Mw) are as described above.

[0074] (cross-linked acrylic resin) The resin layer preferably contains a cross-linked urethane resin and a cross-linked acrylic resin. In the resin layer, the cross-linked urethane resin and the cross-linked acrylic resin preferably have an interpenetrating polymer network structure (IPN structure). The IPN structure is defined as a structure in which the network structures of two or more polymer compounds are intertwined and entangled with each other without being linked by covalent bonds. The IPN structure in the resin layer is preferably formed by the cross-linked acrylic resin penetrating into the network of the three-dimensional cross-linked structure of the cross-linked urethane resin.

[0075] Cross-linked acrylic resin is harder than cross-linked urethane resin, making it possible to increase the hardness of the outermost surface. However, because cross-linked acrylic resin alone is insulating, the surface potential can become extremely high. Furthermore, because cross-linked acrylic resin is brittle, it is prone to scratches caused by abrasion due to friction. On the other hand, when the cross-linked acrylic resin penetrates the three-dimensional cross-linked mesh of the cross-linked urethane resin very close to the outer surface of the resin layer, an IPN structure is formed, which makes it less likely to develop hardness and brittleness, and it is possible to impart high strength while maintaining flexibility.

[0076] Furthermore, the crosslinked acrylic resin is preferably a copolymer of the above-mentioned surface modifier and a (meth)acrylic monomer impregnated therein. This structure is preferable from the viewpoint of controlling the ionization potential and surface potential of the developer carrier and achieving both the desired hardness E1 and E2 of the developer carrier.

[0077] The following method is preferred for forming an IPN structure of cross-linked acrylic resin and cross-linked urethane resin on or near the outer surface of the resin layer: A resin layer containing cross-linked urethane is impregnated with a liquid (meth)acrylic monomer, which is then cured simultaneously with the surface modifier in the resin layer. The content of the cross-linked acrylic resin in the resin layer relative to 100 parts by mass of the cross-linked urethane resin is preferably 1.0 to 5.0 parts by mass, and more preferably 3.0 to 5.0 parts by mass. The thickness of the resin layer is, for example, 3 to 50 μm, preferably 5 to 30 μm, and more preferably 10 to 20 μm.

[0078] 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. Difunctional (meth)acrylic monomers are alkylene glycol di(meth)acrylate, alkylene oxide (ethylene oxide) of alkylene glycol di(meth)acrylate. At least one selected from the group consisting of propylene oxide-modified neopentyl glycol diacrylate is preferred. For example, propylene oxide-modified neopentyl glycol diacrylate is mentioned. Examples of trifunctional (meth)acrylic monomers include trimethylolpropane tri(meth)acrylate and pentaerythritol tri(meth)acrylate.

[0079] The polymerization method of the (meth)acrylic monomer is not particularly limited, and known methods can be used. Specific examples include heating and ultraviolet irradiation. Known radical polymerization initiators and ionic polymerization initiators can be used for each polymerization method. These polymerization initiators may be used alone or in combination of two or more.

[0080] 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.

[0081] (Conductive filler) The resin layer preferably contains a conductive filler to obtain conductivity. It is more preferable to use an electronic conductive agent as the conductive filler in the resin layer. The electronic conductive agent is preferably a conductive particle that exhibits electronic conductivity and has a surface functional group that can interact with a functional group present in the additive described below. Examples of electronic conductive agents that exhibit these properties include at least one selected from the group consisting of carbon black such as furnace black, thermal black, acetylene black, and ketjen black; metal oxide-based conductive particles such as titanium oxide whose surfaces have been treated with acidic functional groups; and metal-based conductive particles such as aluminum and iron whose surfaces have been treated with acidic functional groups. Among these, at least one selected from the group consisting of carbon blacks with highly stable surface functional groups is preferably used. The conductive filler preferably contains carbon black. Furthermore, in order to obtain the desired impedance value and surface potential, carbon black having a number-average diameter of primary particles of 30 nm or less, which allows for higher dispersion in the resin layer, a DBP absorption of 90 ml / 100 g or less, and a pH of 4.0 or less is particularly preferably used.

[0082] When the number-average diameter of the primary particles of carbon black is 30 nm or less, the aggregates (primary agglomerates), which are the smallest dispersible units of carbon black, become small. As a result, the structure (the size of the particle connections) also becomes small, making it difficult to form conductive paths. Therefore, a sufficiently high impedance is easily obtained. The primary particle diameter of carbon black can be calculated using a transmission electron microscope (TEM). The lower the number-average diameter, the better, and there is no particular lower limit. For example, the number-average diameter of the primary particles of carbon black is preferably 5 to 30 nm, and more preferably 20 to 28 nm.

[0083] When the DBP absorption of carbon black is 90 ml / 100 g or less, the carbon black structure becomes small, making it difficult to form conductive paths, and therefore, it is easy to obtain a sufficiently high impedance. The lower the DBP absorption, the better, and there is no particular lower limit. For example, the DBP absorption of carbon black is preferably 30 to 90 ml / 100 g, and more preferably 40 to 60 ml / 100 g.

[0084] When the pH of carbon black is 4.0 or less, the repulsion of the surface functional groups of the carbon black provides dispersion stability, making the carbon black less likely to aggregate, and thus making it easier to obtain a sufficiently high impedance. The lower the pH of carbon black, the more preferable it is, and there is no particular lower limit. For example, the pH of carbon black is preferably 2.0 to 4.0, and more preferably 2.2 to 2.8.

[0085] However, even if the number-average diameter of the primary particles of carbon black, DBP absorption, and pH are within the above ranges, when polycarbonate urethane is used as the binder resin, the carbon black may not be sufficiently dispersed, making it impossible to obtain the desired impedance.The reason why carbon black, which has the desired raw material properties, cannot be dispersed when polycarbonate urethane is used as the binder resin is not clearly understood, but it is speculated as follows.

[0086] The hydroxyl groups, which are surface functional groups of carbon black, tend to interact with the terminal hydroxyl groups of polycarbonate diol. On the other hand, the structure of the carbonate bond and hydrocarbon group bonded between the two hydroxyl groups of polycarbonate diol is hydrophobic due to the presence of the hydrocarbon group, making it less likely to interact with carbon black. Since the structure is more stable when hydrophobic and hydrophilic materials are close together, hydrophilic carbon black will be found in the vicinity of hydrophilic carbon black. As a result, carbon black tends to aggregate and become difficult to disperse.

[0087] In order to sufficiently disperse carbon black having the number average diameter of primary particles, DBP absorption amount, and pH within the above-mentioned ranges when using polycarbonate urethane as a binder resin, it is more preferable to add the additives described below.

[0088] The carbon black content is preferably added so as to obtain a desired volume resistivity, and is preferably 30 parts by mass or less, more preferably 10 to 30 parts by mass, and even more preferably 15 to 25 parts by mass, per 100 parts by mass of the resin component that forms the resin layer. When the amount is 30 parts by mass or less, the distance between the carbon black particles in the coating liquid is maintained at an appropriate level, reducing the probability of collisions due to Brownian motion of the carbon black and making the carbon black less likely to aggregate. This makes the carbon black more easily dispersible and improves dispersion stability. As a result, the carbon black is well dispersed in the resin layer formed by coating the coating liquid.

[0089] To achieve the above-mentioned specific impedance and surface potential, it is preferable to control the dispersion of the carbon black. Regarding the particle size of the dispersed carbon black, when Rc is the arithmetic mean of the equivalent circle diameters of the carbon black in the resin layer, Rc is preferably 60.0 nm or less. Furthermore, when σc [nm] is the standard deviation of the equivalent circle diameters, σc / Rc is preferably 0.000 to 0.650. Furthermore, regarding the distance between the carbon black particles, when the arithmetic mean value of the distance between the wall surfaces of the carbon black particles in the resin layer is d, it is preferable that d is 80.0 to 150.0 nm, and when the standard deviation of the distance between the wall surfaces is σd [nm], σd / d is 0.000 to 0.600.

[0090] The reason why high impedance and low surface potential are more easily achieved when the equivalent circle diameter and wall-to-wall distance are within the above-mentioned ranges is presumed to be as follows. When the dispersed particle size is large, there are areas where the distance between the walls is close, making it easier for conductive paths to form, resulting in lower impedance and surface potential. On the other hand, when the dispersed particle size is small, the distance between the walls becomes more uniform, making it harder for conductive paths to form, increasing resistance, and reducing capacitance, resulting in higher impedance. Regarding surface potential, it is now possible to reduce it, as localized charge accumulation is less likely to occur. If the surface of carbon black is coated with an insulating material such as a silane coupling agent, it will no longer be able to function as a pseudo-capacitor, resulting in high impedance and surface potential. In addition, carbon black can be used as long as it does not affect the impedance value and surface potential. A plurality of types may be used in combination.

[0091] The arithmetic mean value Rc of the equivalent circle diameter is more preferably 40.0 to 60.0 nm, and even more preferably 50.0 to 60.0 nm. σc / Rc is more preferably 0.500 to 0.650, and even more preferably 0.550 to 0.650. σc is more preferably 25.0 to 45.0 nm, and even more preferably 30.0 to 40.0 nm. The arithmetic mean value Rc and standard deviation σc of the equivalent circle diameter can be changed, for example, by the dispersion state in a mill when preparing the coating liquid for forming the resin layer. Weaker dispersion tends to increase Rc and σc, while stronger dispersion tends to decrease Rc and σc. Normally, Rc converges, so once a certain dispersion state is exceeded, σc can be reduced while Rc remains almost constant, and σc / Rc can be reduced.

[0092] The arithmetic mean value d of the distance between the wall surfaces is more preferably 90.0 to 130.0 nm, and even more preferably 105.0 to 115.0 nm. σd / d is more preferably 0.500 to 0.600, and even more preferably 0.550 to 0.590. σd is more preferably 50.0 to 80.0 nm, and even more preferably 60.0 to 70.0 nm. The arithmetic mean value d and standard deviation σd of the wall-to-wall distance can be changed, for example, by the dispersion state in a mill or the like when preparing the resin layer-forming coating liquid. Weaker dispersion tends to make d smaller and σd larger, while stronger dispersion tends to make d larger and σd smaller. Therefore, weaker dispersion tends to make σd / d larger, and stronger dispersion tends to make σd / d smaller.

[0093] (additives) One preferred embodiment involves the use of an additive to further improve the dispersibility of carbon black in a binder resin using polycarbonate urethane. Here, for example, at least one compound selected from the group consisting of a compound having a structure represented by the following structural formula (5), a compound having a structure represented by the following structural formula (6), and a compound having a structure represented by the following structural formula (7) can be suitably used as the additive. One method for incorporating the additive into the surface layer is to incorporate a dispersant into the surface layer-forming coating liquid. Note that in a surface layer formed using a surface layer-forming coating liquid containing at least one compound selected from the group consisting of a compound having a structure represented by the structural formula (5) and a compound having a structure represented by the structural formula (6), the compound may be incorporated at the end of the polyurethane polymer chain. Even in such cases, the effect of improving the dispersibility of carbon black can be expected; however, it is preferable that the additive be present in the surface layer independently of the polyurethane.

[0094] Among the compounds having the structures represented by structural formulas (5) to (7), the compound having the structure represented by structural formula (5) is more preferably used because it has particularly excellent dispersibility of carbon black and affinity with polycarbonate urethane. [ka]

[0095] In structural formula (5), R51 represents a monovalent hydrocarbon group having 1 to 12 carbon atoms (preferably 3 to 12). t and u represent the average number of moles added, and each independently represents a number of 1 or more (preferably 5 to 30, more preferably 10 to 25). In structural formula (6), R61 represents a monovalent hydrocarbon group having 1 to 8 carbon atoms (preferably 1 to 4). v and w represent the average number of moles added, and each independently represents a number of 1 or more (preferably 1 to 30, more preferably 5 to 30). In structural formula (7), R71 represents a monovalent hydrocarbon group having 1 to 12 carbon atoms. x represents the average number of moles added and represents a number of 1 or more (preferably 1 to 30, more preferably 4 to 15).

[0096] Structural formula (5) is polyoxyethylene polyoxypropylene alkyl ether, a polyether monool with a block-type addition polymerization structure of ethylene oxide and propylene oxide. The terminal hydroxyl groups of this polyether monool interact with the surface functional groups of the conductive filler carbon black through hydrogen bonding, acting as a dispersant for the carbon black. In addition, the structure is compatible with polycarbonate urethane, enhancing its effectiveness as a dispersant for carbon black.

[0097] Ethylene oxide is introduced into the structure to ensure uniform distribution of the additive in the polycarbonate urethane. This is thought to be because the ethylene group in ethylene oxide is compatible with the hydrophobic hydrocarbon group in the polycarbonate urethane. Propylene oxide is introduced into the structure to improve the dispersibility of the conductive filler dispersed in the resin layer. This is thought to be because the side-chain methyl group of propylene oxide interacts with the conductive filler, improving dispersibility.

[0098] R51, a monovalent hydrocarbon group having 1 to 12 carbon atoms, is introduced into the structure to allow the additive to be distributed uniformly throughout the polycarbonate urethane. Being a monovalent hydrocarbon group improves compatibility with the hydrophobic hydrocarbon groups in the polycarbonate urethane, allowing the additive to be distributed uniformly throughout the polycarbonate urethane. Having 12 or fewer carbon atoms reduces steric hindrance with the polycarbonate urethane, making it easier for the additive to be distributed uniformly. Furthermore, since the compound of formula (5) has a monool structure, it is less reactive than a diol. As a result, it is less likely to be incorporated into the urethane reaction caused by the reaction of isocyanate with polyol, and the introduction of an ether structure into the polycarbonate urethane results in This makes it less likely that the resistance of the polyurethane will decrease.

[0099] The polyoxyethylene polyoxypropylene alkyl ether can be a commercially available product or can be obtained by synthesis. The synthesis of polyoxyethylene polyoxypropylene alkyl ether can be carried out by carrying out the following step (A) followed by step (B). Note that step (B) may also be carried out on a commercially available product whose structure has already been completed up to step (A).

[0100] Step (A): Reaction of alcohol with ethylene oxide Step (B): Reaction of the product obtained in step (A) with propylene oxide In step (A), the reaction can be carried out by adding ethylene oxide to an alcohol in the presence of a catalyst at 50 to 200°C, more preferably 100 to 160°C. Since ethylene oxide has a boiling point of 10.7°C and is in a gaseous state at this temperature, the reaction is preferably carried out in a pressurized environment in a sealed container. The pressure is preferably 0.1 MPa to 1.0 MPa. The reaction time is not particularly limited, but is preferably about 1 to 3 hours in order to reduce the amount of unreacted ethylene oxide.

[0101] The catalyst may be an acid catalyst or an alkali catalyst, but an alkali catalyst is preferred to facilitate purification after the reaction. Examples of alkali catalysts include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides such as calcium hydroxide and barium hydroxide, ammonium hydroxide, and tertiary amines. In view of the ease and efficiency of the reaction, sodium hydroxide and potassium hydroxide are particularly preferred. Examples of acid catalysts include Bronsted acids such as sulfuric acid and phosphoric acid, and Lewis acids such as stannic chloride and boron trifluoride.

[0102] The amount of catalyst used is preferably 0.1 to 5 mol % per 1 mol of alcohol in the case of sodium hydroxide or potassium hydroxide. Since ethylene oxide reacts with water to produce ethylene glycol, it is important to prevent water from entering the reaction system as much as possible, and a dehydration treatment may be carried out before the reaction in step (A) as necessary.

[0103] Step (B) can be carried out under the same conditions as step (A). Propylene oxide has a boiling point of 34.2°C and is in a gaseous state at reaction temperatures of 50 to 200°C, so the reaction is preferably carried out in a pressurized environment in a sealed container. The catalyst used in step (A) may be used as is, or a new catalyst may be added. When a new catalyst is added, the catalyst used in step (A) is preferred.

[0104] Structural formula (6) is a polyetheramine (monoamine) with a block-type addition polymerization structure of ethylene oxide and propylene oxide. The amino groups at the terminals of this polyetheramine interact with the surface functional groups of the conductive filler carbon black through hydrogen bonding, acting as a dispersant for the carbon black. Furthermore, to enhance its effectiveness as a dispersant, R61, a monovalent hydrocarbon group with 1 to 8 carbon atoms, is introduced, resulting in a structure that is easily compatible with the hydrophobic functional groups of polycarbonate urethane, resulting in a structure that is also highly compatible with polycarbonate urethane.

[0105] The polyether monoamine can be a commercially available product or can be obtained by synthesis. The synthesis of the polyether monoamine can be carried out by carrying out the following step (C) followed by step (D).

[0106] Step (C): Oxidation reaction of the compound of structural formula (5), which is a secondary alcohol Step (D): Reductive amination of the product obtained in step (C) Step (C) is a reaction in which a secondary alcohol is oxidized to produce a ketone. The synthesis of ketones by the oxidation of alcohols can be carried out using heavy metal salts and their derivatives, such as chromic acid and manganese dioxide, or non-heavy metal salts, such as dimethyl sulfoxide (DMSO) and hypohalous acids, such as hypochlorous acid.

[0107] Although either method can be used for synthesis, oxidation reactions using hypohalous acids such as dimethyl sulfoxide (DMSO) or hypochlorous acid are preferred due to the environmental impact of heavy metals. Furthermore, dimethyl sulfoxide (DMSO) can undergo explosive reactions at room temperature depending on the electrophilic activating reagent used, requiring temperatures as low as -60°C, making the method using hypohalous acids more preferable. Examples of hypohalous acids include hypochlorites such as sodium hypochlorite and calcium hypochlorite (bleaching powder). Ketones can be obtained by reacting these hypochlorites with secondary alcohols in acetic acid.

[0108] When using dimethyl sulfoxide (DMSO), an electrophilic activating reagent is required. The electrophilic activating reagent increases the electrophilicity of the sulfur in DMSO, allowing it to undergo nucleophilic attack by the alcohol's hydroxyl group. This nucleophilic attack generates a dimethylalkoxysulfonium salt, which decomposes to yield a ketone and dimethyl sulfide. Examples of electrophilic activating reagents include dicyclohexylcarbodiimide (DCC), acetic anhydride, phosphorus pentoxide, sulfur trisulfide-pyridine complex, trifluoroacetic anhydride, oxalyl chloride, and halogens.

[0109] Step (D) is a reductive amination reaction that converts a ketone to an amine. The reaction is divided into two steps. First, a carbonyl group reacts with an amine to generate an iminium cation. Next, a hydride reducing agent nucleophilically attacks the iminium cation to generate an amine. A borohydride reagent is preferably used as the reducing agent. Examples of borohydride reagents include sodium cyanoborohydride, sodium triacetoxyborohydride, and 2-picoline borane. Among these, sodium triacetoxyborohydride and 2-picoline borane are preferred due to their low toxicity. In the reductive amination reaction using a borohydride reagent, if the reagent has a bulky structure, steric hindrance makes it difficult to generate an iminium cation. Therefore, R61 in structural formula (6) is preferably a monovalent hydrocarbon group having 1 to 8 carbon atoms.

[0110] Structural formula (7) is polyoxyethylene alkyl ether acetic acid. The terminal carboxylic acid in structural formula (7) interacts with the surface functional groups of the conductive filler carbon black through hydrogen bonding, acting as a dispersant for the carbon black. In addition, to enhance its effectiveness as a dispersant, R71, a monovalent hydrocarbon group with 1 to 12 carbon atoms, is introduced, resulting in a structure that is easily compatible with the hydrophobic functional groups of polycarbonate urethane, resulting in a structure that is also compatible with polycarbonate urethane.

[0111] Polyoxyethylene alkyl ether acetic acid can be obtained by synthesis or commercially available products. Polyoxyethylene alkyl ether acetic acid can be synthesized by carrying out the following step (E) followed by step (F). Note that step (F) may also be carried out on a commercially available product whose structure has been completed up to step (E). Step (E): Reaction of alcohol with ethylene oxide Step (F): Oxidation reaction of the primary alcohol, which is the product of step (E) Step (E) is the same as step (A) and can be prepared by the same method as step (A).

[0112] Step (F) is a step in which a primary alcohol is oxidized to produce a carboxylic acid. Since the oxidation of a primary alcohol produces an aldehyde, followed by further oxidation to produce a carboxylic acid, it is necessary to select a reaction method and conditions that do not stop at the aldehyde. Methods for obtaining carboxylic acids by oxidation of alcohols include oxidation with an oxidizing agent and catalytic dehydrogenation using a catalyst. Oxidizing agents include permanganate, chromic acid, ruthenium tetroxide, and hypochlorite. Dehydrogenation catalysts include palladium, platinum, iridium, rhodium, and manganese.

[0113] The compounds represented by structural formulas (5) to (7) function as dispersants for carbon black and have high affinity with polycarbonate urethane. Surfactants are typically used to improve the dispersibility and dispersion stability of carbon black. However, the compounds represented by structural formulas (5) to (7) have a low number of functional groups that interact with the surface functional groups of carbon black, resulting in weak surfactant properties and making them uncommonly used. Coupling agents and nonionic surfactants are commonly used as dispersants for carbon black.

[0114] Silane coupling agents, titanate coupling agents, and aluminum coupling agents are used as coupling agents, while polyester and polyether-based nonionic surfactants are used. However, adding these dispersants to polycarbonate urethane to a level that sufficiently enhances the dispersibility of carbon black (50 to 100% by mass relative to the carbon black) inhibits the conductivity of the carbon black and binder resin. Conversely, adding them in an amount that does not inhibit the conductivity of the carbon black and binder resin (10 to 40% by mass relative to the carbon black) does not result in sufficient dispersibility of the carbon black.

[0115] The content of the compounds represented by structural formulas (5) to (7) in the resin layer is preferably within the following range: 3.0 to 7.0 mass % of the compounds represented by structural formulas (5) to (7), and 18.9 to 46.0 mass parts per 100 mass parts of carbon black. By ensuring that the content of the additive in the resin layer is within the above range, the dispersibility of the carbon black in the polyurethane is further improved, and the desired impedance value and surface potential can be more easily achieved.

[0116] The presence of additives in the resin layer can be confirmed and quantitatively evaluated by the following method. The resin layer of the developer carrier is cut out, and the cut piece is subjected to, for example, 1 H-NMR, 13 By using C-NMR, XPS, and FT-IR, it is possible to detect the carbonate structure of the binder resin, and the ether structure, amine structure, and carboxylic acid structure of the additive in the resin layer, and the ratio can be calculated from the peak ratio, etc. Alternatively, sections can be extracted by immersing them overnight in an organic solvent such as 2-butanone (methyl ethyl ketone; MEK), and the extract and the extracted sections can be analyzed. 1 H-NMR, 13 By using C-NMR, XPS, and FT-IR, it is possible to calculate the ratio of additives that are incorporated into the resin during the polymerization reaction and those that are not.

[0117] Examples of the structure in which at least one of the compounds having the structures represented by structural formulas (5) and (6) is bonded to polyurethane (the structure resulting from the reaction during polymerization of polyurethane) include the following. In the case of the structure represented by structural formula (5), in polyurethane, the compound having the structure represented by structural formula (5) is a urethane structure. In the case of the structure represented by structural formula (6), in polyurethane, the compound having the structure represented by structural formula (6) is a urea-modified structure.

[0118] [Roughening particles] The resin layer may contain roughening particles, which may be, for example, spherical particles. The particle diameter of the roughening particles is preferably in the range of, for example, 1 μm to 150 μm, and more preferably in the range of 5 μm to 30 μm. For example, at least one spherical particle selected from the following particles can be used. Urethane resin particles, acrylic resin particles, phenolic resin particles, silicone resin particles, polyacrylonitrile resin particles, polystyrene resin particles, polyurethane resin particles, nylon resin particles, polyethylene resin particles, polypropylene resin particles, preferably urethane resin particles. The content of the roughening particles in the resin layer is preferably 1 to 20% by mass, more preferably 5 to 15% by mass.

[0119] [Middle layer (elastic layer)] The electrophotographic roller may have an elastic layer as an intermediate layer 13 on the outer surface of the substrate. The electrophotographic roller has the elastic layer between the substrate and the resin layer, for example. There are no particular limitations on the elastic layer, and any known elastic layer for electrophotographic rollers may be used. For example, a cured product of an addition-curing liquid silicone rubber mixture may be used. The thickness of the intermediate layer may be, for example, 1.0 to 20.0 mm, or 8.0 to 15.0 mm.

[0120] 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.

[0121] (Resin layer manufacturing method) The method for producing an electrophotographic roller preferably includes the steps of preparing a substrate having a conductive outer surface and forming a resin layer on the outer surface side of the substrate. The step of forming the resin layer preferably includes the step of applying and curing a urethane raw material mixture containing a urethane raw material for forming a crosslinked urethane resin and a surface modifier to obtain a crosslinked urethane resin. Furthermore, it is preferable to impregnate the crosslinked urethane resin with a (meth)acrylic monomer for forming a crosslinked acrylic resin, and polymerize the surface modifier and the (meth)acrylic monomer to form a crosslinked acrylic resin to obtain the resin layer.

[0122] 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.

[0123] 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.

[0124] As the solvent, a polar solvent is preferred from the viewpoint of compatibility with polyols and isocyanate compounds, which are raw materials for the crosslinked urethane resin. Examples of polar solvents include alcohols such as methanol, ethanol, and n-propanol, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, and esters such as methyl acetate and ethyl acetate. Of these, solvents that are compatible with other materials can be used alone or in combination of two or more.

[0125] The solid content when forming the paint can be freely adjusted by the amount of solvent mixed, but from the viewpoint of uniformly dispersing the electronically conductive material such as carbon black, which will be described later, it is preferably 20% by mass or more and 40% by mass or less. For dispersion and mixing, known dispersion devices using beads such as a sand mill, paint shaker, dyno mill, and pearl mill can be used. In addition, the coating method and For application, dip coating, ring coating, spray coating or roll coating can be used.

[0126] For example, a liquid coating is obtained by mixing polyol, an isocyanate compound, and other binder resin raw materials, a conductive filler, a surface modifier, additives, and the like. The resin layer coating is then applied to the substrate. The resulting coating is then dried and solidified, or heated and cured to form a cross-linked urethane resin. By adjusting the weight-average molecular weight of the surface modifier to 200 to 3000, the surface modifier can be easily oriented near the surface without seeping out to the surface. At this point, the surface modifier remains unreacted near the surface in the cross-linked urethane resin chain.

[0127] Next, the resin layer formed as described above is impregnated with a liquid (meth)acrylic monomer. The liquid (meth)acrylic monomer can be used as is or as an impregnation treatment liquid diluted appropriately with various solvents. By appropriately diluting the liquid (meth)acrylic monomer with various solvents, a resin layer with a more uniform surface composition can be obtained.

[0128] The solvent can be freely selected as long as it has both affinity with the resin layer and solubility for the (meth)acrylic monomer, for example, alcohols such as methanol, ethanol, and n-propanol, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, and esters such as methyl acetate and ethyl acetate.

[0129] In addition, a polymerization initiator is appropriately mixed into the impregnation treatment liquid. Details of the polymerization initiator are as described above. The impregnation method with the impregnation treatment liquid is not particularly limited, but dip coating, ring coating, spray coating, or roll coating can be used. After the impregnation treatment, the air drying time is preferably limited to 15 minutes or less to prevent the surface modifier added to the resin layer from seeping out to the surface due to the solvent in the impregnation treatment liquid. Then, the material is dried at 90°C for 1 hour to volatilize the solvent.

[0130] After the impregnation treatment with the impregnation treatment solution, the (meth)acrylate monomer or oligomer added to the resin layer as a surface modifier and the (meth)acrylic monomer resulting from the impregnation treatment are simultaneously polymerized and cured. As the reaction progresses, the (meth)acrylate monomer or oligomer added to the resin layer is bulky and thus orients toward the outermost surface while curing. This process facilitates the formation of an IPN structure in which the groups derived from the surface modifier, such as silicone groups and fluorine groups, are oriented toward the outermost surface, and the interlocking structures are easily formed near the surface of the crosslinked urethane resin network structure. The polymerization and curing methods are not particularly limited, and known methods can be used. Specific examples include heat curing and ultraviolet irradiation.

[0131] <Developer> Next, the developer will be described. The developer is, for example, a toner. The toner preferably has toner particles containing a binder resin and an external additive on the surface of the toner particles.

[0132] Examples of vinyl resins used as binder resins include the following. Homopolymers of styrene and its substituted derivatives, such as polystyrene and polyvinyltoluene; Styrene copolymers such as styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer -based copolymer; Polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, polyester resin, polyamide resin, epoxy resin, polyacrylic acid.

[0133] These may be used alone or in combination of two or more. Among these, styrene copolymers, and styrene-butyl acrylate copolymers are particularly preferred from the viewpoint of ease of control of development characteristics and fixability.

[0134] <Wax> Next, the wax will be described. The toner particles may contain wax. As the wax, waxes known for use in developers can be used. For example, petroleum waxes and their derivatives such as paraffin wax, microcrystalline wax, petrolatum, etc.; Montan wax and its derivatives; Fischer-Tropsch hydrocarbon waxes and their derivatives; Polyolefin waxes such as polyethylene and their derivatives; Examples of suitable waxes include natural waxes such as carnauba wax and candelilla wax, and their derivatives. Derivatives include oxides, block copolymers with vinyl monomers, and graft-modified products. Other waxes that can be used include higher aliphatic alcohols, fatty acids such as stearic acid and palmitic acid, acid amide waxes, ester waxes, hydrogenated castor oil and its derivatives, vegetable waxes, and animal waxes. The content of the wax is preferably 1 to 30 parts by mass with respect to 100 parts by mass of the binder resin.

[0135] <Coloring agent> Next, the colorant will be described. The toner particles may contain a colorant. The colorant is selected in consideration of hue angle, saturation, brightness, light resistance, transparency on an overhead projector, and dispersibility in a developer. As the black colorant, carbon black, magnetic fine particles, and a yellow colorant / magenta colorant / cyan colorant (described later) can be used to obtain a black color. Since many dyes and carbon black have polymerization inhibitor properties, care must be taken when producing a developer through polymerization. When producing a magnetic developer, it is preferable to use magnetic fine particles as the black colorant, and the magnetic fine particles preferably have a number-average particle size of 0.10 to 0.40 μm. The content of the magnetic fine particles is preferably 20 to 200 parts by mass, more preferably 40 to 150 parts by mass, per 100 parts by mass of the polymerizable monomer or binder resin.

[0136] Examples of yellow colorants include compounds such as condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds.Specific examples include the following CI Pigment Yellow 12, 13, 14, 15, 17, 62, 73, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 128, 129, 138, 147, 150, 151, 154, 155, 168, 180, 185, and 214.

[0137] Examples of magenta colorants include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specific examples include the following: CI Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, 238, 254, 269, and CI Pigment Violet 122. Examples include No. 19.

[0138] Cyan colorants include copper phthalocyanine compounds and their derivatives, anthraquinone compounds, and basic dye lake compounds, specifically CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, and 66. These colorants can be used alone or in combination, or in the form of a solid solution. The content of the colorant other than the magnetic fine particles is preferably 1 to 20 parts by mass relative to 100 parts by mass of the polymerizable monomer or binder resin.

[0139] <Manufacturing method> The method for producing the developer is not particularly limited, and the developer can be produced by a pulverization method, a dispersion polymerization method, an association-aggregation method, a dissolution suspension method, a suspension polymerization method, or the like. The developer particles (particles before adding external additives) contained in the developer can be produced by a pulverization method, but are preferably produced in an aqueous medium by a dispersion polymerization method, an association-aggregation method, a dissolution suspension method, a suspension polymerization method, or the like, and among these, the suspension polymerization method is more preferable.

[0140] The suspension polymerization method involves dissolving or dispersing a colorant, and optionally a polymerization initiator, a crosslinking agent, a charge control agent, and other additives, in a polymerizable monomer to obtain a polymerizable monomer composition. The polymerizable monomer composition is then added to an aqueous medium (which may optionally contain a dispersion stabilizer) to form particles of the polymerizable monomer composition, and the polymerizable monomer contained in the particles is polymerized to obtain developer particles. The developer obtained by the suspension polymerization method (hereinafter also referred to as a "polymerized developer") has individual developer particles that are nearly spherical, which tends to improve fluidity at the regulating section and facilitate uniform triboelectric charging, thereby tending to improve image quality.

[0141] Examples of the polymerizable monomer used in the production of the polymer developer include the following. The polymerizable monomers include: Styrenic monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, and p-ethylstyrene; acrylic acid esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate; Methacrylate esters such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate; Other examples include acrylonitrile, methacrylonitrile, acrylamide, etc. These may be used alone or in combination.

[0142] Among the above-mentioned polymerizable monomers, it is preferable to use styrene or styrene derivatives alone or in combination from the viewpoint of the development characteristics and durability of the developer.

[0143] The polymerization initiator preferably has a half-life of 0.5 to 30.0 hours during the polymerization reaction, and is preferably used in an amount of 0.5 to 20.0 parts by mass per 100 parts by mass of the polymerizable monomer. Specific examples of the polymerization initiator include azo or diazo polymerization initiators such as 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, and azobisisobutyronitrile; Examples of the peroxide polymerization initiator include diisopropyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, t-butyl peroxy 2-ethylhexanoate, and t-butyl peroxypivalate.

[0144] When the developer particles are produced by a polymerization method, a crosslinking agent may be added, and the preferred amount added is 0.01 to 5.00 parts by mass per 100 parts by mass of the polymerizable monomer. As the crosslinking agent, a compound having two or more polymerizable double bonds is mainly used, and examples thereof include the following: Aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, etc.; Carboxylic acid esters having two double bonds, such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol dimethacrylate; divinyl compounds, such as divinylaniline, divinyl ether, divinyl sulfide, and divinyl sulfone; A compound containing three or more vinyl groups. These may be used alone or in combination of two or more.

[0145] Various surfactants, organic dispersants, and inorganic dispersants can be used as dispersion stabilizers in aqueous media. Inorganic dispersants are particularly preferred because they are less likely to produce harmful ultrafine powders and achieve dispersion stability through steric hindrance. Examples of such inorganic dispersants include polyvalent metal phosphates such as tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, and hydroxyapatite; carbonates such as calcium carbonate and magnesium carbonate; inorganic salts such as calcium metasilicate, calcium sulfate, and barium sulfate; and inorganic compounds such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide.

[0146] These inorganic dispersants are preferably used in an amount of 0.2 to 20.0 parts by mass per 100 parts by mass of the polymerizable monomer. The dispersion stabilizers may be used alone or in combination of two or more. Furthermore, a surfactant may be used in combination.

[0147] The resulting resin particles are filtered, washed, and dried to obtain toner particles as developer particles. After drying, the particles may be classified into coarse particles and fine particles, and external additives such as inorganic fine particles may be added to the toner particles.

[0148] <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, in addition to the inorganic fine particles, inorganic fine particles having a primary particle number-average particle size of 100 to 200 nm may be used in combination. This ensures the fluidity of the developer throughout durability, and improves the concentration.

[0149] Inorganic fine particles are added to improve the fluidity of the developer and to control the chargeability of developer particles. In the present invention, it is necessary to select inorganic fine particles from the viewpoint of controlling the charge series of the developer. In order to control the charge series to negative chargeability, it is possible to treat the surface of the inorganic fine particles with a silicone oil or a fluorine-based treating agent. Conversely, in order to control the charge series to positive chargeability, it is necessary to treat the surface of the inorganic fine particles with a treating agent such as aminosilane. The number average particle size of the primary particles of the inorganic fine particles is measured using a photograph of the developer taken enlarged with a scanning electron microscope.

[0150] As inorganic fine particles, fine particles of silica, titanium oxide, alumina, etc., or fine particles of composite oxides thereof can be used. As silica fine particles, for example, dry silica produced by vapor phase oxidation of silicon halide, or dry silica called fumed silica, can be used. silica, and hydrated silica. The amount of inorganic fine particles added is preferably 0.1 to 4.0 parts by mass per 100 parts by mass of developer particles. The content of inorganic fine particles can be determined by fluorescent X-ray analysis using a calibration curve prepared from standard samples.

[0151] The triboelectric series of a developer is expressed by the value of ionization potential. The ionization potential I(T) of the developer is preferably 4.0 to 5.6 eV, and more preferably 4.5 to 5.6 eV. Within this range, it is easy to control the difference in ionization potential of the developer carrier within a suitable range. The ionization potential I(T) of the developer can be controlled by the surface treatment agent of the external additive used in the developer. The external additive is preferably surface-treated. I(T) can be easily lowered by a surface treatment agent having an amino group. Furthermore, I(T) can be easily increased by a surface treatment agent having fluorine.

[0152] <Process cartridge and electrophotographic image forming apparatus> The developer carrier according to the present disclosure can be suitably used as a developer carrier, a developer supply roller, and a developing sleeve in a process cartridge. Fig. 3 is a schematic cross-sectional view of an example of a process cartridge according to one embodiment of the present disclosure. In Fig. 3, the developer carrier is mounted as developer carrier 14.

[0153] The process cartridge 22 is configured to be detachably mountable to the main body of the electrophotographic image forming apparatus. The process cartridge 22 integrates a developing device 18 including a developer carrier 14 and a developer layer thickness regulating member 15, a photosensitive member 19, a charging roller 20, and a cleaning blade 21. The developer layer thickness regulating member 15 is, for example, a developing blade. The developing device 18 further has a developer storage section filled with developer 16. The developer 16 is supplied to the surface of the developer carrier 14 by a developer supply roller 17, and the developer layer thickness regulating member 15 forms a layer of developer 16 of a predetermined thickness on the surface of the developer carrier 14.

[0154] The developer carrier 14 is in contact with the photosensitive member 19 and is driven to rotate at a predetermined peripheral speed ratio relative to the photosensitive member 19. The developer layer thickness regulating member 15 has at least a portion electrically conductive and has a contact point electrically connected to the developer layer thickness regulating member. When this process cartridge is installed in the main body of an electrophotographic image forming apparatus, this contact point is electrically connected to a main body contact point of the main body, allowing a predetermined voltage to be applied to the developer layer thickness regulating member. In addition, a predetermined bias is applied to the developer carrier 14, and the electrostatic latent image on the photosensitive member 19 is developed and visualized using the developer 16.

[0155] The developer supply roller 17 contacts the developer carrier 14, penetrates it by a predetermined amount, and rotates in the same direction as the rotation of the developer carrier 14. A bias of the same potential as the bias applied to the developer carrier 14 is applied to the developer supply roller 17.

[0156] One end of the developer layer thickness regulating member 15 is fixed to the developing device 18, and the other free end is arranged in contact with the developer carrier 14 in the counter direction to the rotation direction. By arranging the developer layer thickness regulating member 15 in contact with the developer carrier 14, the amount of developer on the developer carrier 14 is regulated, making the layer thinner and forming a uniform developer layer thickness. In addition, a predetermined bias is applied to the developer layer thickness regulating member 15, which imparts an electric charge to the developer 16.

[0157] 4 is a schematic cross-sectional view showing an example of an electrophotographic image forming apparatus in which the developer carrier is mounted as a developer carrier of a contact-type developing device using a one-component developer. The developing device 18 includes a developer 16 as a one-component developer, a developer carrier 14, a developer supply roller 17 that supplies the developer to the developer carrier 14, and a developer layer thickness regulation roller that regulates the thickness of the developer layer on the developer carrier 14. The developing device 18 includes a control member 15. The developer carrier 14 is located in an opening extending in the longitudinal direction within the developing device 18, and is installed in contact with the photosensitive member 19. The photosensitive member 19, charging roller 20, and cleaning blade 21 may be provided in the main body of the electrophotographic image forming apparatus. The developing device 18 is provided with developers of black, cyan, magenta, and yellow, enabling color printing.

[0158] The printing operation of an electrophotographic image forming apparatus will now be described. Photoconductor 19 rotates in the direction of the arrow and is uniformly charged by charging roller 20, which charges photoconductor 19. Next, an electrostatic latent image is formed on the surface of photoconductor 19 by laser light 23, which serves as exposure means. The electrostatic latent image is visualized as a developer image (developed) by developer device 18, which applies developer 16 from developer carrier 14, which is placed in contact with photoconductor 19. Development is so-called reversal development, in which a developer image is formed in the exposed area.

[0159] The developer image formed on the photosensitive member 19 is transferred onto an intermediate transfer member 25 in the form of an endless belt by a transfer roller 24 which is a transfer member. Paper 26, which is a recording medium, is fed into the device by paper feed roller 27 and secondary transfer roller 28, and is transported together with intermediate transfer body 25 carrying a developer image to the nip between secondary transfer roller 28 and driven roller 29, where the developer image is transferred to paper 26. Intermediate transfer body 25 is operated by driven roller 29, drive roller 30, and tension roller 31. Any developer remaining on intermediate transfer body 25 is cleaned by cleaning device 32.

[0160] A voltage is applied from a bias power supply 33 to the developer carrier 14, developer layer thickness regulating member 15, transfer roller 24, and secondary transfer roller 28. The paper 26 onto which the developer image has been transferred is fixed by a fixing device 34 and then ejected outside the device, completing the printing operation. Meanwhile, residual developer remaining on the photoreceptor 19 without being transferred is scraped off by a cleaning blade 21, which is a cleaning member for cleaning the surface of the photoreceptor. The cleaned photoreceptor 19 repeats the above printing operation.

[0161] <Impedance> In impedance measurements, the response of the developer carrier is examined when AC and DC voltages are applied while changing the frequency. An AC voltage is applied and measurements are divided into two responses: one with no phase shift relative to the applied AC voltage, and one with a phase shift of π / 2. The impedance of the response with no phase shift is plotted on a complex plane as Z' (real part) and the impedance of the response with a phase shift is plotted as Z" (imaginary part), and the distance from the origin to the plot is calculated as the impedance value. When the electrical characteristics of the developer carrier are represented pseudo-wise by an RC parallel circuit, the real part without phase shift represents the resistance component, and the imaginary part with phase shift represents the capacitance component. Note that the measurement conditions and the meaning of the measured values were explained in the previous section (2), so they will not be explained here.

[0162] The impedance measurement method, measurement device, and measurement conditions are described below. (Method of measuring impedance) The impedance of the developer carrier can be measured by the following methods (1) and (2). (1) A method in which a thin film electrode is placed on the surface of the developer carrier and measurement is performed using two terminals, one on the electrode and the other on the substrate. (2) A method in which the developer carrier is pressed against a metal drum with a constant load and measured at two terminals on the metal drum and the substrate.

[0163] Although impedance can be measured by either method, method (2) is affected by the nip width and contact area between the developer carrier and the metal drum, so it is necessary to measure using a developer carrier with the same hardness. Therefore, in this disclosure, measurement is performed using method (1). Below, we will explain the method (1). The measurement method will be described below, and more specific conditions will be described later. When measuring impedance, in order to eliminate the influence of contact resistance between the developer carrier and the measurement electrode, it is preferable to deposit a low-resistance thin film on the surface of the developer carrier, use the thin film as an electrode, and measure the impedance using two terminals, with the conductive substrate as a ground electrode.

[0164] Examples of methods for forming the thin film include metal deposition, sputtering, applying a metal paste, and attaching a metal tape. Among these, from the viewpoint of reducing contact resistance with the developer carrier, a method of forming a metal thin film such as platinum or palladium as an electrode by vapor deposition is preferred. In the present disclosure, vacuum platinum vapor deposition is used.

[0165] When forming a metal thin film on the surface of a developer carrier, it is preferable to provide a vacuum deposition apparatus with a mechanism capable of gripping the developer carrier, taking into consideration the ease of the process and the uniformity of the thin film. In addition, for developer carriers with a cylindrical cross section, it is preferable to use a vacuum deposition apparatus further equipped with a rotation mechanism.

[0166] It is preferable to form a thin metal film electrode approximately 10 mm wide in the longitudinal direction of the developer carrier, and then connect a metal sheet wrapped tightly around the thin metal film electrode in a direction intersecting the longitudinal direction to the measuring electrode protruding from the measuring device for measurement. In the case of a cylindrical developer carrier, it is preferable to use a metal sheet wrapped tightly around the circumferential direction of the developer carrier. This allows impedance measurement to be performed without being affected by fluctuations in the size of the outer edge (outer diameter for cylindrical developer carriers) in the cross section perpendicular to the longitudinal direction of the developer carrier, or by the surface shape. Aluminum foil, metal tape, etc. can be used as the metal sheet.

[0167] (Impedance measurement conditions) The impedance measurement equipment is an impedance analyzer, a network analyzer, a spectrum analyzer, etc., and is 1.0 x 10 -1 ~1.0×10 5 Any device capable of measuring impedance in a frequency range up to 100 Hz may be used. Among these, it is preferable to measure the impedance using an impedance analyzer in the electrical resistance range of the developer carrier.

[0168] The impedance measurement conditions are as follows: An impedance measurement device was used, and the impedance was measured at 1.0 x 10 -1 ~1.0×10 5 The impedance is measured in the frequency range of 100 Hz. The measurement environment is a temperature of 23°C and a relative humidity of 50%. To account for measurement variations, it is preferable to measure at least nine points in total: three points along the length of the developer carrier and three points in the rotational direction. The voltage application condition is a DC voltage of 50 V superimposed on an AC voltage of 50 V.

[0169] <Surface potential> In an environment of 23°C temperature and 50% relative humidity, a corona discharger with a 3.0 mm wide grid was placed so that the distance between the grid and the outer surface of the developer carrier was 1.0 mm and the width direction of the grid was aligned with the axial direction of the developer carrier. A voltage of 8 kV was applied to the grid, and the corona discharger was moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier. The potential of the outer surface 0.06 seconds after passing the grid was measured, and the degree of overcharging (charge-up) of the developer was evaluated.

[0170] The surface potential of the developer carrier can be measured, for example, by the device shown in Figure 8. Both ends of the substrate 82 of the developer carrier 81 are held by chucks 83, and a measuring unit 86, which has a corona discharger 84 and a surface potential meter 85 arranged in parallel at an interval of 25 mm, is placed opposite the surface of the developer carrier 81 at a distance of 1.0 mm. With the developer carrier 81 stationary, a voltage of 8 kV is applied to the grid part of the corona discharger 84, and the measuring unit 86 is The developer carrier 81 is moved in the axial direction at a speed of 400 mm / sec, and the surface potential is measured by a surface potentiometer 85 0.06 seconds after passing through the corona discharger 84 .

[0171] <Ionization potential> The ionization potential is measured by the following measurement method. The ionization potential is expressed numerically as the energy (eV) required to remove an electron from a substance. The ionization potential is measured using a surface analyzer (product name: AC-5, manufactured by Riken Keiki Co., Ltd.). A deuterium lamp is used in the above-mentioned device, and measurements are made under the following conditions. Irradiation power: 800nW Spectrometer: Grating monochromator Spot size: 2mm x 4mm Energy scan range: 4.0~6.2[eV] Measurement time: 5 [sec / 1 energy] Then, photoelectrons emitted from the sample surface are detected and processed using ionization potential calculation software installed in the surface analysis device.

[0172] In the surface analysis, when the excitation energy of monochromatic light is scanned from low to high in 0.05 eV intervals, photon emission begins at a certain energy value [eV], and this energy threshold is taken as the ionization potential [eV].

[0173] An example of a work function measurement curve obtained under the above conditions is shown in Figure 11. In Figure 11, the horizontal axis represents excitation energy [eV], and the vertical axis represents the 0.5th power of the number of emitted photoelectrons (normalized quantum yield) Y. Generally, when the excitation energy value exceeds a certain threshold, photoelectrons are rapidly emitted. In other words, the normalized quantum yield increases. The value of excitation energy required when the normalized quantum yield begins to increase is defined as the ionization potential.

[0174] <Method for measuring elastic modulus> The elastic modulus is measured using a scanning probe microscope (SPM). First, a region including a cross section of the resin layer in the thickness direction is cut into a thin section using a cryomicrotome (product name: EMFC6, manufactured by Leica Microsystems) with a diamond knife while maintaining the temperature at -110° C. Then, a sample measuring 100 μm square and 100 μm wide in the depth direction is prepared from the thin section.

[0175] 12 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. 12, a region from the outer surface of the resin layer 12 that forms the outer surface of the developer carrier to a depth of 0.1 μm is defined as a first region 87, and a region from the outer surface to a depth of 1.0 to 1.1 μm is defined as a second region 88. The elastic modulus was measured in each region of the cross section of the prepared sample. Measurements were performed using an SPM device (product name: MFP-3D-Origin, Oxford Instruments) and a probe (product name: AC160, Olympus). After first acquiring a 5 μm square topography image, force curves were measured 10 times in each of the first and second regions 87 and 88, which do not contain the roughness-forming particles or carbon black. The arithmetic mean of the eight points excluding the highest and lowest values was calculated, and the elastic modulus was calculated using Hertz's theory. The elastic moduli in the first and second regions 87 and 88 were designated E1 and E2, respectively.

[0176] Regarding the meaning of E1 in the first region, it is as described above. E2 in the second region is the elastic modulus at a depth of 1.0 to 1.1 μm from the outer surface, and it is preferable that the elastic modulus E2 is 1 to 100 MPa. When E2 in the second region is within the above range, deterioration of the developer in the durability evaluation can be suppressed, and high-quality images can be provided throughout the durability.

[0177] <Verification of IPN structure> The verification of the IPN structure is performed by micro-sampling mass spectrometry. Micro-sampling mass spectrometry uses an ion trap type mass spectrometer. The sample is fixed to the filament located at the tip of the probe and directly inserted into the ionization chamber. Then, it is rapidly heated from room temperature to a temperature of 1000 °C at a constant heating rate. The sample decomposed and evaporated by heating is ionized by irradiation with an electron beam and detected by a mass spectrometer.

[0178] At this time, under the condition that the heating rate is constant, a thermal chromatogram similar to the TG-MS (thermogravimetry-mass simultaneous analysis) method with a mass spectrum called total ion chromatogram (TIC) can be obtained. Also, since a thermal chromatogram for a fragment of a predetermined mass can also be obtained, the peak temperature of the thermal chromatogram corresponding to the decomposition temperature of the desired molecular structure can be obtained. The peak temperature of the thermal chromatogram is correlated with the crosslinked structure in the resin structure, and as the crosslinking becomes denser, the peak temperature will shift to the higher temperature side. That is, compared with the crosslinked acrylic resin alone, the part where the crosslinked urethane resin and the crosslinked acrylic resin form an IPN structure has a higher peak temperature in the thermal chromatogram.

[0179] A peak top temperature A1 of a thermal chromatogram derived from a cross-linked acrylic resin is obtained from a first sample obtained from a first region, which is a region extending from the outer surface of the resin layer to a depth of 0.1 μm. Furthermore, a peak top temperature A2 of a thermal chromatogram derived from the cross-linked acrylic resin is measured from a second sample obtained by decomposing the cross-linked urethane resin contained in the first sample. When an IPN structure is formed, A1 will be higher than A2 in terms of the peak temperature of the thermal chromatogram. A2 is a value obtained by performing microsampling mass spectrometry on a second sample obtained after decomposing the crosslinked urethane by the pyridine decomposition method described below. Examples of A1 include 390 to 398°C and 393 to 397°C. Examples of A2 include 385 to 395°C and 390 to 394°C.

[0180] <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.

[0181] Using a microtome, a 0.1 μm thick sample was cut from the outer surface of the resin layer of the developer carrier, and 500 mg of the sample was collected. 0.5 mL of a 3:1 mixture of pyridine (Wako Pure Chemical Industries, Ltd.) and water was added to the resulting sample, which was then decomposed by heating at 130°C for 15 hours in a sealed container made of fluororesin (Teflon®) with a stainless steel jacket. The resulting decomposition product was then subjected to reduced pressure to remove the pyridine. The sample thus obtained was subjected to the microsampling mass spectrometry described above to obtain the A2 value.

[0182] <Structural analysis of cross-linked acrylic resin> The presence of silicone groups and / or fluorine groups in the crosslinked acrylic resin molecules can be analyzed by known means such as pyrolysis GC / MS (gas chromatograph mass spectrometer), FT-IR (Fourier transform infrared spectrometer), and NMR (nuclear magnetic resonance spectrometer). The structure derived from the crosslinked urethane was removed by the pyridine method, and the resulting crosslinked acrylic resin was confirmed using FT-IR (trade name: FT / IR-4700, manufactured by JASCO Corporation, FT-IR). [Example]

[0183] 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.

[0184] [1. Preparation and manufacturing of raw materials for forming resin layer] <1-1. Preparation of raw polyol and manufacturing example> A synthesis example for obtaining a polyurethane resin layer will be shown below.

[0185] [Measurement of number average molecular weight of raw material polyol] The apparatus and conditions used for measuring the number average molecular weight (Mn) in this production example are as follows. Measuring device: HLC-8120GPC (Tosoh Corporation) Column: TSKgel Super HZMM (Tosoh Corporation) x 2 Solvent: tetrahydrofuran (THF) (20 mmol / l triethylamine added) Temperature: 40℃ THF flow rate: 0.6 ml / min The measurement sample was a 0.1% by mass THF solution. Furthermore, the measurement was carried out using an RI (refractive index) detector as the detector. A calibration curve was created using TSK standard polystyrenes A-1000, A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40, F-80, and F-128 manufactured by Tosoh Corporation as standard samples. Based on this calibration curve, the number average molecular weight was calculated from the retention time of the obtained measurement sample.

[0186] <Raw polyol> Raw material polyols A-1 to A-5 were prepared. The details are shown in Table 1.

[0187] [Table 1]

[0188] <1-2. Preparation of raw material isocyanates B-1 to B-3> Raw material isocyanates B1 to B3 were prepared. The details are shown in Table 2.

[0189] [Table 2]

[0190] <1-3. Production Examples of Hydroxyl-Terminated Urethane Prepolymers C-1 to C-3> [Synthesis of hydroxyl-terminated urethane prepolymer C-1] Under a nitrogen atmosphere, the materials listed in Table 3 below were reacted by heating and stirring at a temperature of 90°C for 3 hours. 2-Butanone (MEK) was then added to the resulting reaction product to prepare a solution with a solid content of 50 parts by mass, thereby producing hydroxyl-terminated urethane prepolymer C-1.

[0191] [Synthesis of hydroxyl-terminated urethane prepolymers C-2 and C-3] Hydroxyl-terminated urethane prepolymers C-2 and C-3 were prepared using the raw materials listed in Table 3 below in the same manner as in the synthesis of hydroxyl-terminated urethane prepolymer C-1. The chemical structures of these hydroxyl group-terminated urethane prepolymers C-1 to C-3 are as follows: 1 H-NMR and 13 The molecular weights were determined using C-NMR. In Table 3, m, n, o, p, q, r, and s in the structural formulae (1), (2), (3), and (4) represent the average number of moles added.

[0192] [Table 3] For the hydroxyl group-terminated urethane prepolymers C-1 and C-2, each of which contains the structure shown in structural formula (1) in its molecule, R13 in structural formula (1) was the same as R12. In the tables, the description "x, y = A", such as m and n = 6.9, indicates that the average number of moles added of x and y is A. The same applies to the following tables.

[0193] <1-4. Production Examples of Isocyanate-Terminated Prepolymers D-1 to D-3> [Synthesis of isocyanate-terminated prepolymer D-1] The materials listed in Table 4 below were reacted under a nitrogen atmosphere by heating and stirring at 90°C for 3 hours. 2-Butanone (MEK) was then added to the resulting reaction product to prepare a solution with a solid content of 50 parts by mass, producing isocyanate-terminated prepolymer D-1.

[0194] [Synthesis of isocyanate-terminated prepolymers D-2 and D-3] Isocyanate-terminated prepolymers D-2 and D-3 were prepared using the types and amounts of raw materials shown in Table 4 below in the same manner as in the synthesis of isocyanate-terminated prepolymer D-1. The chemical structures of these isocyanate group-terminated prepolymers D-1 to D-3 are as follows: 1 H-NMR and 13 The molecular weights of the compounds were determined using C-NMR. In Table 7, m, n, o, p, q, r, and s in the structural formulae (1), (2), (3), and (4) represent the average number of moles added.

[0195] [Table 4] For the isocyanate group-terminated prepolymer D-2 containing the structure represented by structural formula (1) in the molecule, R13 in structural formula (1) was the same as at least one selected from the group consisting of R11 and R12.

[0196] <2. Preparation of resin layer additive raw materials> <2-1. Preparation of polyoxyethylene polyoxypropylene alkyl ether> [Preparation of polyoxyethylene polyoxypropylene alkyl ether] The details of polyoxyethylene polyoxypropylene alkyl ethers E-1 to E-3 are shown in Table 5.

[0197] [Table 5]

[0198] <Surface modifier> The materials used as surface modifiers are listed in Table 6.

[0199] [Table 6]

[0200] <Impregnation treatment solution> The materials shown in Table 7 below were dissolved and mixed to prepare the impregnation solution for the impregnation treatment.

[0201] [Table 7]

[0202] 3. Example of manufacturing developer carrier In this embodiment, a developer carrier is described in which a resin layer is coated on an elastic roller having an elastic layer on the outer surface of a base body, but the present invention is not limited to this configuration.

[0203] [3-1. Adjustment of the base] A substrate was prepared by applying a primer (product name: DY35-051, manufactured by Dow Toray Industries, Inc.) to the circumferential surface of a 6 mm diameter core bar made of stainless steel (SUS304) and baking it (130°C, 5 minutes).

[0204] [3-2. Preparation 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 8 was poured into the cavity formed in the mold.

[0205] [Table 8]

[0206] Next, the mold was heated to vulcanize and harden the silicone rubber at a temperature of 150°C for 15 minutes, and after demolding, it was further heated at a temperature of 180°C for 1 hour to complete the hardening reaction, resulting in an elastic roller with an elastic layer with a diameter of 11.5 mm on the outer periphery of the base body.

[0207] [3-3. Preparation of coating liquid for forming resin layer] The materials for the resin layer-forming coating solution, the types and amounts of which are listed in Table 9 below, were added to a reaction vessel and stirred. Next, 2-butanone (MEK) was added so that the total solids ratio was 30% by mass, and the mixture was mixed using a sand mill. Next, 2-butanone (MEK) was added to adjust the viscosity of the solution to within the range of 6 to 10 mPa·s, and the resin layer-forming coating solution was prepared.

[0208] [Table 9]

[0209] [3-4. Preparation of cross-linked urethane resin in resin layer] The elastic roller was oriented with its longitudinal direction in the vertical direction, and its upper end was gripped and immersed in the resin layer-forming coating solution to coat the surface of the elastic roller. 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, an elastic roller was obtained with a 12 μm-thick resin layer of cross-linked urethane resin formed on the elastic layer.

[0210] [3-5. Impregnation treatment] Next, impregnation and curing treatment of an acrylic monomer capable of forming a crosslinked acrylic resin was carried out by the following method. The impregnation treatment liquids used for the impregnation treatment were those shown in Tables 7 and 10. The elastic roller on which the tan resin had been formed was immersed in the above-mentioned impregnation treatment solution 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 an integrated light intensity of 15,000 mJ / cm. 2 The acrylic monomer was cured by irradiating it with ultraviolet light so that an IPN structure was formed, thereby obtaining a developer carrying member 1. As the ultraviolet irradiator, a high-pressure mercury lamp (product name: handy type UV curing device, manufactured by Mario Network Co., Ltd.) was used. The physical properties of the resulting developer carrier 1 are shown in Table 10.

[0211] <Production of Developer Carriers 2 to 11> Developer carriers 2 to 11 were produced in the same manner as developer carrier 1, except that the materials and the quantities were changed as shown in Table 10. The physical properties of the resulting developer carriers 2 to 11 are shown in Table 10. Note that when the question about whether or not the impregnation treatment liquid step was performed is marked "Yes," the above-mentioned impregnation treatment was carried out. Conversely, when the question is marked "No," the impregnation treatment was not carried out.

[0212] [Table 10] In the table, for example, "9.12E+06" means "9.12 x 10 6 A1 is the above-mentioned peak top temperature A1 (°C), and A2 is the above-mentioned peak top temperature A2 (°C). In developer carriers 1 to 5, an IPN structure consisting of a cross-linked urethane resin and a cross-linked acrylic resin was confirmed, but in the other developer carriers, the IPN structure was not confirmed.

[0213] <Manufacture of Developer Carrier 12> The types and amounts of materials listed in Table 11 below were added to a reaction vessel and stirred. Next, 2-butanone (MEK) was added so that the total solids ratio was 30% by mass, and then the mixture was mixed in a sand mill. Next, 2-butanone (MEK) was added to adjust the viscosity of the liquid to within the range of 6 to 10 mPa·s. The mixture was adjusted to prepare a coating material for forming a resin layer.

[0214] The elastic roller obtained in the production of developer carrier 1 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 liquid to coat the surface of the elastic roller with the coating liquid. 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 was formed on the elastic roller having a 12 μm-thick resin layer formed on the elastic layer, thereby obtaining developer carrier 12. The physical properties of developer carrier 12 are shown in Table 10.

[0215] [Table 11]

[0216] <Manufacture of Developer Carrier 13> Developer carrier 13 was produced in the same manner as in the production of developer carrier 1, except that additive E-1 was changed to 14 parts of a silane coupling agent (product name: A-187, manufactured by Momentive Corporation) and the impregnation step was not performed. The physical properties of developer carrier 13 are shown in Table 10.

[0217] <Manufacture of Developer Carrier 14> A fluorine-based release agent (product name: Frelease 310, manufactured by Neos Corporation) was applied in advance to the mold used in the production of the elastic roller described above, and a liquid of a foam material in which the following materials (A) to (F) were blended and dispersed was poured into the mold. (A): Polyol A (polyethylene propylene ether triol having a number average molecular weight of 3100, trade name: Actocol EP-550N; manufactured by Mitsui Chemicals SKC Polyurethanes Co., Ltd.): 100.0 parts by mass (B): Polyisocyanate mixture (NCO%=45, MDI=20%, trade name: Cosmonate TM-20; manufactured by Mitsui Chemicals SKC Polyurethanes Co., Ltd.): 23.9 parts by mass (C): Silicone foam stabilizer (product name: SRX274C, manufactured by Dow Corning Toray Co., Ltd.): 1.0 part by mass (D): 0.3 parts by mass of tertiary amine catalyst A (a mixture of bis(2-dimethylaminoethyl) ether and dipropylene glycol, trade name: TOYOCAT-ET, manufactured by Tosoh Corporation) (E): Amine catalyst B (trade name: TOYOCAT-L33, manufactured by Tosoh Corporation): 0.2 parts by mass (F): Blowing agent (water): 1.4 parts by mass After the foam material was injected, the mold was heated at 75°C for 7 minutes and then removed from the mold. By the above method, an elastic roller having an elastic layer containing a urethane foam resin was produced.

[0218] This elastic roller was coated with PTFE paint (polytetrafluoroethylene). In this way, a developer carrier 14 was obtained in which the surface of a porous body was coated with Teflon (registered trademark) resin. The physical properties of the developer carrier 14 are shown in Table 10.

[0219] 4. Example of developer manufacturing <Manufacturing of treated magnetic materials> An aqueous solution containing ferrous hydroxide was prepared by mixing 1.00 to 1.10 equivalents of caustic soda solution relative to elemental iron, P2O5 in an amount equivalent to 0.15 mass% of phosphorus relative to elemental iron, and SiO2 in an amount equivalent to 0.50 mass% of silicon relative to elemental iron into an aqueous solution of ferrous sulfate. The pH of the solution was adjusted to 8.0, and an oxidation reaction was carried out at 85°C while blowing in air to prepare a slurry containing seed crystals.

[0220] Next, a ferrous sulfate solution was added to the slurry to a concentration of 0.90 to 1.20 equivalents relative to the initial alkali content (sodium content of caustic soda). The pH of the slurry was maintained at 7.6, and air was blown in to allow the oxidation reaction to proceed, yielding a slurry containing magnetic iron oxide. After filtration and washing, the aqueous slurry was temporarily removed. A small amount of aqueous sample was collected and its water content was measured. Next, the aqueous sample was placed in another aqueous medium without drying, and redispersed using a pin mill while stirring and circulating the slurry. The pH of the redispersion was adjusted to approximately 4.8. Then, 1.6 parts of n-hexyltrimethoxysilane (the amount of magnetic iron oxide was calculated by subtracting the water content from the aqueous sample) was added to 100 parts of magnetic iron oxide while stirring, and hydrolysis was carried out. After thorough stirring, the pH of the dispersion was adjusted to 8.6, and surface treatment was performed. The resulting hydrophobic magnetic material was filtered using a filter press, washed with a large amount of water, and then dried at 100°C for 15 minutes and at 90°C for 30 minutes. The resulting particles were then crushed to obtain a treated magnetic material with a number-average particle size of 0.21 μm.

[0221] <Production of amorphous polyester> The raw material monomers were prepared as shown below and placed in a reaction vessel equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple, and then 1.5 parts of dibutyltin catalyst per 100 parts of the total amount of monomers was added. Next, the temperature was quickly raised to 180°C under normal pressure in a nitrogen atmosphere, and then water was distilled off while heating from 180°C to 210°C at a rate of 10°C / hour to carry out polycondensation. After the temperature reached 210°C, the pressure in the reactor was reduced to 5 kPa or less, and polycondensation was carried out at 210°C and 5 kPa or less to obtain an amorphous polyester. The number average molecular weight of the obtained amorphous polyester was 7800 and the glass transition temperature was 73°C. Bisphenol A (propylene oxide 2 mole adduct) 90.0 parts Terephthalic acid 74.0 parts Trimellitic anhydride 4.0 parts

[0222] <Example of manufacturing developer particles> 450 parts of 0.1 mol / L Na3PO4 aqueous solution was added to 720 parts of ion-exchanged water and heated to 60°C, and then 67.7 parts of 1.0 mol / L CaCl2 aqueous solution was added to obtain an aqueous medium containing a dispersion stabilizer. Styrene 75.0 parts n-Butyl acrylate 25.0 parts Amorphous polyester Divinylbenzene 0.6 parts 65.0 parts of the above-mentioned treated magnetic material The above formulation was dispersed and mixed using an attritor (Mitsui Miike Chemical Engineering Co., Ltd.) to obtain a monomer composition. This monomer composition was heated to 63°C, and 5.0 parts of ester wax (melting point 70°C) was added and mixed thereto to dissolve. Thereafter, a polymerization initiator, tert-butylperoxypivalate, was added thereto. 6.0 parts of ethanol were dissolved in the mixture.

[0223] The monomer composition was added to the aqueous medium and granulated by stirring at 12,000 rpm for 10 minutes in a TK homomixer (Tokushu Kika Kogyo Co., Ltd.) at 60°C under a N2 atmosphere. The mixture was then reacted at 70°C for 4 hours while stirring with a paddle impeller. After the reaction was completed, it was confirmed that colored particles were dispersed in the aqueous medium obtained and that calcium phosphate was attached to the surface of the colored particles as an inorganic dispersant. Thereafter, hydrochloric acid was added to the aqueous medium to dissolve the calcium phosphate, and the mixture was washed, filtered, and dried to obtain developer particles.

[0224] <Silica fine particles> The raw silica particles were surface-treated with the treating agents shown in Table 12 to obtain silica particles 1 to 3. The details of silica particles 1 to 3 are shown in Table 12. The raw silica particles had a BET specific surface area of 120 m 2 / g of silica fine particles (number average particle size of primary particles: 12 nm).

[0225] [Table 12]

[0226] <Production of developer (toner) 1> Developer 1 was prepared by mixing 100 parts by mass of the developer particles and the silica fine particles 1 shown in Table 12 in the number of parts by mass shown in Table 13 using a Henschel mixer (Mitsui Miike Chemical Engineering Co., Ltd.). The physical properties of developer 1 are shown in Table 13.

[0227] [Table 13] The number of parts indicates parts by mass.

[0228] <Production of Developers (Toners) 2 to 7> Developers 2 to 7 were produced in the same manner as in the production of developer 1, except that in the production of developer 1, the hydrophobic silica fine particles shown in Table 12 were used and the number of parts of the hydrophobic silica fine particles was changed to that shown in Table 13. The physical properties of developers 2 to 7 are shown in Table 13.

[0229] Example 1 <Impedance measurement> The impedance was measured as follows. First, as a pretreatment, a measurement electrode was fabricated by vacuum vapor deposition of platinum onto a rotating developer carrier. Vacuum deposition was performed using a vacuum vapor deposition device with a mechanism for gripping and rotating the base of the carrier, the object to be coated, in the circumferential direction. The carrier rotation speed, deposition distance, and deposition time were controlled to achieve a film thickness of 100 nm or more. Masking tape was used to fabricate a 1.5 cm wide, circumferentially uniform electrode. Forming this electrode with a film thickness of 100 nm or more minimizes the contribution of the contact area between the measurement electrode and the developer carrier due to the surface roughness of the developer carrier.

[0230] Next, an aluminum sheet was wrapped tightly around the electrode, and the aluminum sheet was connected to the measurement electrodes of an impedance measuring device (product names: Solartron 1260 and Solartron 1296, manufactured by Solartron Corporation) and a high-voltage system (product names: 6792 and HVA-500, manufactured by Toyo Corporation).

[0231] Figure 5 shows a schematic diagram of the state in which the measurement electrodes are formed on the developer carrier. In Figure 5, 51 is a conductive substrate, 52 is a resin layer, 53 is a platinum vapor deposition layer, and 54 is an aluminum sheet. In this figure, the elastic layer is not shown, but it exists between the substrate 51 and the resin layer 52.

[0232] Figure 6 shows a cross-sectional view of the developer carrier with the measurement electrode formed on it. 61 is the conductive substrate, 62 is the elastic layer, 63 is the resin layer, 64 is the platinum vapor deposition layer, and 65 is the aluminum sheet. As shown in Figure 6, it is important to sandwich the resin layer between the conductive substrate and the measurement electrode.

[0233] The aluminum sheet was then connected to the measurement electrodes of an impedance measurement device (Solatron 1260 and Solartron 1296, manufactured by Solartron) and a high-voltage system (product names: 6792 and HVA-500, manufactured by Toyo Corporation). Figure 7 shows a schematic diagram of this measurement system. Impedance measurements were performed using the conductive substrate and the aluminum sheet as the two electrodes for measurement.

[0234] The impedance was measured at a temperature of 23°C and a relative humidity of 50%, with a DC voltage of 50V and an AC voltage of 50V applied, and a frequency of 1.0 x 10 -1 ~1.0×10 5 The absolute value of the impedance was obtained in Hz.

[0235] <Surface potential measurement> The surface potential of the developer carrier was measured using a charge amount measuring device (product name: DRA-2000L, manufactured by QEA). Specifically, in an environment of 23°C temperature and 50% relative humidity, the grid part of the corona discharger of the charge amount measuring device was positioned so that the gap between it and the outer surface of the developer carrier was 1.0 mm. The grid part of the corona discharger of the above device was 3.0 mm wide. Next, a voltage of 8 kV was applied to the corona charger, and the corona charger was moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the surface of the conductive member, and the potential of the outer surface was measured 0.06 sec after passing the grid section. The maximum value of all measurements taken at eight locations in the longitudinal direction at 45° intervals around the circumference of the electrophotographic roller was used.

[0236] <Calculation of various physical properties such as the equivalent circle diameter and wall distance of carbon black dispersed in a resin layer> The particle size of the carbon black dispersed in the resin layer and the wall-to-wall distance were measured by the following method. First, a slice (0.5 to 1.0 mm thick) is cut out using a razor so that a cross section perpendicular to the longitudinal direction of the developer carrier can be observed. If the adhesion between the substrate and the resin layer is high and cutting out with a razor is difficult, the substrate can be cut out with a hacksaw or similar tool, and then the cross section can be processed using a FIB (Focused Ion Beam) device.

[0237] Next, the slice is platinum-deposited, and the resin layer is photographed at 15,000x magnification using a scanning electron microscope (SEM) (trade name: JSM-7800F, manufactured by JEOL Ltd.) to obtain a cross-sectional image. Furthermore, to quantify the cross-sectional images obtained by SEM observation, the cross-sectional images were converted to 8-bit grayscale using image processing software (trade name: Luzex AP, manufactured by Nireco Corporation) to obtain a monochrome image with 256 gradations. Next, the black and white of the image were inverted so that the carbon black in the cross-sectional image appeared white, and then a binarization threshold was set for the brightness distribution of the image based on the algorithm of Otsu's discriminant analysis method, obtaining a binarized image in which the carbon black appeared white and the binder resin appeared black.

[0238] Then, using image processing software (trade name: Luzex AP, manufactured by Nireco Corporation) on the obtained binarized image, the equivalent circle diameter and the distance between adjacent wall surfaces of the whitened carbon black portions are calculated. The image region for calculating the equivalent circle diameter and the distance between adjacent wall surfaces is set to an area 0.075 μm inside in actual image dimensions (if there is a text section describing the SEM measurement conditions, etc., then 0.075 μm inside from where the actual image begins) to eliminate uncertainty in the calculated values for the carbon black that is divided at the top, bottom, left, and right edges of the image, and the equivalent circle diameter and the distance between adjacent wall surfaces are calculated for all carbon black within the specified image region. The arithmetic mean and standard deviation are then calculated for the distribution of the obtained circle equivalent diameter and the distance between adjacent wall surfaces. Although there is no particular problem with using only one image for image analysis, at least three images are used to eliminate the influence of differences in the longitudinal direction of the carbon black dispersed in the resin layer of the developer carrier.

[0239] 5. Image Evaluation The image evaluation method will be explained below. The electrophotographic image forming apparatus used was a modified version of a commercially available laser printer, the LBP-7600C (manufactured by Canon Inc.). The configuration of the modified apparatus is shown in Figure 10. The modified parts included connecting to power supplies 14C and 15C as well as an external high-voltage power supply 20C, allowing any potential difference to be set between the developer layer thickness regulating member and the developer carrier, and the output rate per unit time was set to 50 sheets / minute for A4 size paper in order to evaluate a high-speed process. The process cartridge used was a commercially available developer cartridge 318 (black) (manufactured by Canon Inc.), and the developer and developer carrier were replaced with the combinations shown in Table 14. At this time, the developer filling amount was adjusted to 100 g. The product developer was removed from each of the yellow, cyan, and magenta stations, and evaluations were performed by inserting yellow, cyan, and magenta cartridges with the developer remaining amount detection mechanism disabled.

[0240] [5-1.Fog evaluation] The prepared process cartridge was mounted in the main body of an electrophotographic image forming apparatus and left in an environment of 30°C temperature and 80% relative humidity for 24 hours. Thereafter, an external high-voltage power supply was used to set the potential difference between the developer layer thickness regulating member and the developer carrier to -300V, and in the same environment, an image of a 4-point alphabet letter "E" was continuously printed on an A4 evaluation paper (GF-C081, manufactured by Canon Inc.) with a print rate of 2% of the area of the A4-sized paper. A solid white image was printed every 1,000 sheets, and this was repeated up to 20,000 sheets. The fogging value was measured by the following method. Ten solid white images were output in succession at one time, and the fog values of the first and tenth images were used.

[0241] 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 "fogging value" of the developer carrier. The reflection density was measured over the entire image printing area of the recording material, and the maximum value was used. The smaller the fog value, the better, and normally, the developer is not transferred onto the transfer paper on which a solid white image has been formed. If the developer charge is insufficient, the developer moves onto the photoreceptor even when a solid white image is formed, and is then transferred onto the transfer paper, increasing the fog value. Fog was evaluated when no sheets had been output (initial), and after 20,000 sheets had been output, and the fog values on the first and tenth sheets were evaluated, respectively. The evaluation results are shown in Table 14. In addition, since fogging tends to occur more easily in high temperature and humidity environments such as a temperature of 30°C and a relative humidity of 80%, the evaluation was carried out in an environment of a temperature of 30°C and a relative humidity of 80%.

[0242] <Roughness evaluation> Coarseness was evaluated by dot reproducibility. The prepared process cartridge was installed in the main body of an electrophotographic image forming apparatus and left in an environment of 15°C and 10% relative humidity for 24 hours. Then, using an external high-voltage power supply, the potential difference between the developer layer thickness regulating member and the developer carrier was set to -300V. In this environment, an image of a 4-point "E" letter was continuously printed on A4 evaluation paper (GF-C081, manufactured by Canon Inc.) with a print coverage of 2% of the A4 paper area. A solid white image was printed every 1,000 sheets, and this process was repeated until 20,000 sheets were printed to form a halftone (30H) image, which was then evaluated for dot reproducibility. A 30H image is a halftone image where 256 gradations are expressed in hexadecimal, with 00H representing solid white (no image) and FFH representing a solid image (full image).

[0243] The images were taken using a digital microscope VHX-500 (lens wide range zoom lens VH-Z100 manufactured by Keyence Corporation), and the area of 1,000 dots was measured. The number average (S) of the dot area and the standard deviation (σ) of the dot area were calculated, and the dot reproducibility index was calculated using the following formula. The halftone image was then evaluated using the dot reproducibility index (I). The smaller the value of the dot reproducibility index (I), the better the dot reproducibility. Dot reproducibility index (I) = σ / S × 100 In addition, since roughness tends to occur more easily in low temperature and low humidity environments such as a temperature of 15°C and a relative humidity of 10%, the evaluation was carried out in an environment with a temperature of 15°C and a relative humidity of 10%. The results of the evaluation of Example 1 are set forth in Table 14.

[0244] Examples 2 to 13 In Examples 2 to 13, measurements and evaluations were carried out in the same manner as in Example 1, except that the developer carrier and developer were changed to those shown in Table 14. The evaluation results are shown in Table 14.

[0245] [Table 14]

[0246] (Comparative Examples 1 to 6) In Comparative Examples 1 to 6, measurements and evaluations were carried out in the same manner as in Example 1, except that the developer carrier and developer were changed to those shown in Table 14. The evaluation results are shown in Table 14.

[0247] The present disclosure relates to the following configurations. (Configuration 1) A developer; a developer carrier; a developer layer thickness regulating member that contacts the developer carrier and regulates the layer thickness of the developer carried on the developer carrier; a contact point electrically connected to the developer layer thickness regulating member; a developer containing member that contains the developer; A process cartridge having the process cartridge is detachably mountable to the main body of the electrophotographic image forming apparatus, At least a part of the developer layer thickness regulating member is conductive, the contact is electrically connected to a contact of the main body of the electrophotographic image forming apparatus when the process cartridge is mounted in the main body of the electrophotographic image forming apparatus, thereby enabling a predetermined voltage to be applied to the developer layer thickness regulating member, The developer carrier is a substrate having an electrically conductive outer surface; a resin layer present on the outer surface side of the substrate; and A metal film is directly provided on the outer surface of the developer carrier, and the developer is then subjected to an environmental test at a temperature of 23°C and a relative humidity of 50%. While applying a DC voltage of 50 V between the outer surface of the substrate and the metal film, an AC voltage with an amplitude of 50 V and a frequency of 1.0 × 10 -1 ~1.0×10 5 When applied while changing between Hz, the frequency is 1.0 × 10 0 ~1.0×10 1 Impedance at Hz is 1.00 x 10 6 is greater than or equal to Ω, When the ionization potential of the developer is I(T) and the ionization potential of the outer surface of the developer carrier is I(R), I(T) and I(R) satisfy the following formula (X): │I(T)-I(R)│≦0.3eV ···(X) In an environment of a temperature of 23°C and a relative humidity of 50%, a corona discharger having a grid portion with a width of 3.0 mm is arranged so that the distance between the grid portion and the outer surface of the developer carrier is 1.0 mm and the direction of the width of the grid portion coincides with the axial direction of the developer carrier, a voltage of 8 kV is applied to the grid portion, and the corona discharger is moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier, and the maximum value of the potential when measured 0.06 seconds after the grid portion has passed is less than 20.0 V. A process cartridge characterized by: (Configuration 2) 2. The process cartridge according to claim 1, wherein the ionization potential I(T) of the developer is 4.0 to 5.6 eV. (Configuration 3) 3. The process cartridge according to claim 1, wherein the elastic modulus E1 of the resin layer measured in a cross section in the thickness direction in a region from the outer surface of the developer carrier to a depth of 0.1 μm is 200 MPa or more. (Configuration 4) 4. The process cartridge according to Configuration 3, wherein the elastic modulus E2 measured in a cross section of the resin layer in the thickness direction in a region from the outer surface of the developer carrier to a depth of 1.0 to 1.1 μm is 1 to 100 MPa. (Configuration 5) 5. The process cartridge according to any one of Configurations 1 to 4, wherein the resin layer contains polyurethane having a polycarbonate structure. (Configuration 6) 6. The process cartridge according to claim 5, wherein the polyurethane satisfies at least two of the following (A), (B), and (C): (A) The polyurethane has a structure represented by the following structural formula (1) in its molecule: (B) The polyurethane has at least one structure selected from the group consisting of a structure represented by the following structural formula (2) and a structure represented by the following structural formula (3) in the molecule: (C) The polyurethane has a structure represented by the following structural formula (4) in the molecule: TIFF2025116839000020.tif135153 In structural formula (1), R11, R12, and R13 represent divalent hydrocarbon groups having 3 to 9 carbon atoms. However, R11 and R12 are different from each other, and R13 is the same as at least one selected from the group consisting of R11 and R12. m and n represent the average number of moles added, and each independently represents a number of 1.0 or more. In the structural formula (2), o and p are the average number of moles added, and each independently represents a number of 1.0 or more. In structural formula (3), R31 and R32 each independently represent a divalent hydrocarbon group having 3 to 8 carbon atoms, and q and r each independently represent the average number of moles added and are each a number of 1.0 or greater. In structural formula (4), R41 represents a divalent hydrocarbon group having 6 to 9 carbon atoms, and s represents the average number of moles added and is a number of 1.0 or more. (Configuration 7) the polyurethane is a cross-linked urethane resin, the resin layer further contains a crosslinked acrylic resin, In the resin layer, the cross-linked urethane resin and the cross-linked acrylic resin form an interpenetrating polymer network (IPN). The process cartridge according to aspect 5 or 6. (Configuration 8) the resin layer contains carbon black, When the arithmetic mean value of the equivalent circle diameter of the carbon black in the resin layer is defined as Rc, Rc is 60.0 nm or less, When the standard deviation of the equivalent circle diameter is σc, σc / Rc is 0.000 to 0.650. The process cartridge according to any one of Configurations 1 to 7. (Configuration 9) the resin layer contains carbon black, When the arithmetic mean value of the distance between the wall surfaces of the carbon black in the resin layer is d, d is 80.0 to 150.0 nm; When the standard deviation of the distance between the wall surfaces is σd, σd / d is 0.000 to 0.600. The process cartridge according to any one of Configurations 1 to 8. (Configuration 10) 10. The process cartridge according to any one of Configurations 1 to 9, wherein the outer surface of the resin layer is the outer surface of the developer carrier. (Configuration 11) a main body of an electrophotographic image forming apparatus; a process cartridge detachably attached to the main body; An electrophotographic image forming apparatus having: The process cartridge is the process cartridge according to any one of Configurations 1 to 10, the main body has main body contacts that are electrically connected to the contacts of the process cartridge when the process cartridge is attached to the main body; When the process cartridge is mounted in the main body, a predetermined voltage can be applied to the developer layer thickness regulating member. Electrophotographic image forming apparatus characterized in that: (Configuration 12) A developer; a developer carrier; a developer layer thickness regulating member that contacts the developer carrier and regulates the layer thickness of the developer carried on the developer carrier; a developer containing member that contains the developer; An electrophotographic image forming apparatus having: At least a part of the developer layer thickness regulating member is conductive, a predetermined voltage can be applied to the developer layer thickness regulating member; The developer carrier is a substrate having an electrically conductive outer surface; a resin layer present on the outer surface side of the substrate; and A metal film was provided directly on the outer surface of the developer carrier, and a DC voltage of 50 V was applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%, while an AC voltage of 50 V amplitude and a frequency of 1.0×10 -1 ~1.0×10 5 When applied while changing between Hz, the frequency is 1.0 × 10 0 ~1.0×10 1 Impedance at Hz is 1.00 x 10 6 is greater than or equal to Ω, When the ionization potential of the developer is I(T) and the ionization potential of the outer surface of the developer carrier is I(R), I(T) and I(R) satisfy the following formula (X): │I(T)-I(R)│≦0.3eV ···(X) In an environment of a temperature of 23°C and a relative humidity of 50%, a corona discharger having a grid portion with a width of 3.0 mm is arranged so that the distance between the grid portion and the outer surface of the developer carrier is 1.0 mm and the direction of the width of the grid portion coincides with the axial direction of the developer carrier, a voltage of 8 kV is applied to the grid portion, and the corona discharger is moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier, and the maximum value of the potential when measured 0.06 seconds after the grid portion has passed is less than 20.0 V. Electrophotographic image forming apparatus characterized in that: [Explanation of symbols]

[0248] 10: developer carrier; 11: substrate; 12: resin layer; 14. Developer carrier, 15. Developer layer thickness regulating member, 16. Developer, 17. Developer supply roller, 18. Developing device, 19. Photosensitive member, 20. Charging roller, 21. Cleaning blade, 22. Process cartridge

Claims

1. A developer; a developer carrier; a developer layer thickness regulating member that contacts the developer carrier and regulates the layer thickness of the developer carried on the developer carrier; a contact point electrically connected to the developer layer thickness regulating member; a developer containing member that contains the developer; A process cartridge having the process cartridge is detachably mountable to the main body of the electrophotographic image forming apparatus, At least a part of the developer layer thickness regulating member is conductive, the contact is electrically connected to a contact of the main body of the electrophotographic image forming apparatus when the process cartridge is mounted in the main body of the electrophotographic image forming apparatus, thereby enabling a predetermined voltage to be applied to the developer layer thickness regulating member, The developer carrier is a substrate having an electrically conductive outer surface; a resin layer present on the outer surface side of the substrate; and A metal film was provided directly on the outer surface of the developer carrier, and a DC voltage of 50 V was applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%, while an AC voltage of 50 V amplitude was applied at a frequency of 1.0×10 －１ ~1.0 x 10 ５ When applied while changing between 1.0 x 10 Hz, ０ ~1.0 x 10 １ Impedance at Hz is 1.00 x 10 ６ is greater than or equal to Ω, When the ionization potential of the developer is I(T) and the ionization potential of the outer surface of the developer carrier is I(R), I(T) and I(R) satisfy the following formula (X): │I(T)-I(R)│≦0.3eV ...(X) In an environment of a temperature of 23°C and a relative humidity of 50%, a corona discharger having a grid portion with a width of 3.0 mm is arranged so that the distance between the grid portion and the outer surface of the developer carrier is 1.0 mm and the direction of the width of the grid portion coincides with the axial direction of the developer carrier, a voltage of 8 kV is applied to the grid portion, and the corona discharger is moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier, and the maximum value of the potential of the outer surface measured 0.06 seconds after the grid portion has passed is less than 20.0 V. A process cartridge characterized by:

2. 2. The process cartridge according to claim 1, wherein the ionization potential I(T) of said developer is 4.0 to 5.6 eV.

3. 2. The process cartridge according to claim 1, wherein the elastic modulus E1 of the resin layer measured in a cross section in the thickness direction in a region from the outer surface of the developer carrier to a depth of 0.1 μm is 200 MPa or more.

4. 4. The process cartridge according to claim 3, wherein the elastic modulus E2 measured in a cross section in the thickness direction of the resin layer in a region at a depth of 1.0 to 1.1 μm from the outer surface of the developer carrier is 1 to 100 MPa.

5. 2. The process cartridge according to claim 1, wherein the resin layer contains polyurethane having a polycarbonate structure.

6. 6. The process cartridge according to claim 5, wherein the polyurethane satisfies at least two of the following (A), (B), and (C): (A) The polyurethane has a structure represented by the following structural formula (1) in the molecule: (B) The polyurethane has at least one structure selected from the group consisting of a structure represented by the following structural formula (2) and a structure represented by the following structural formula (3) in the molecule: (C) The polyurethane has a structure represented by the following structural formula (4) in the molecule: In structural formula (1), R11, R12, and R13 represent divalent hydrocarbon groups having 3 to 9 carbon atoms. However, R11 and R12 are different from each other, and R13 is the same as at least one selected from the group consisting of R11 and R12. m and n represent the average number of moles added, and each independently represents a number of 1.0 or more. In the structural formula (2), o and p are the average number of moles added, and each independently represents a number of 1.0 or more. In structural formula (3), R31 and R32 each independently represent a divalent hydrocarbon group having 3 to 8 carbon atoms. q and r each independently represent the average number of moles added and are each a number of 1.0 or greater. In structural formula (4), R41 represents a divalent hydrocarbon group having 6 to 9 carbon atoms, and s represents the average number of moles added and is a number of 1.0 or more.

7. the polyurethane is a cross-linked urethane resin, the resin layer further contains a crosslinked acrylic resin, In the resin layer, the cross-linked urethane resin and the cross-linked acrylic resin form an interpenetrating polymer network (IPN). The process cartridge according to claim 5 .

8. the resin layer contains carbon black, When the arithmetic mean value of the equivalent circle diameter of the carbon black in the resin layer is defined as Rc, Rc is 60.0 nm or less, When the standard deviation of the equivalent circle diameter is σc, σc / Rc is 0.000 to 0.

650. The process cartridge according to claim 1 .

9. the resin layer contains carbon black, When the arithmetic mean value of the distance between the wall surfaces of the carbon black in the resin layer is d, d is 80.0 to 150.0 nm, When the standard deviation of the distance between the wall surfaces is σd, σd / d is 0.000 to 0.

600. The process cartridge according to claim 1 .

10. 2. The process cartridge according to claim 1, wherein the outer surface of said resin layer is the outer surface of said developer carrying member.

11. a main body of an electrophotographic image forming apparatus; a process cartridge detachably attached to the main body; An electrophotographic image forming apparatus having: The process cartridge is the process cartridge according to any one of claims 1 to 10, the main body has main body contacts that are electrically connected to the contacts of the process cartridge when the process cartridge is attached to the main body; When the process cartridge is mounted in the main body, a predetermined voltage can be applied to the developer layer thickness regulating member. Electrophotographic image forming apparatus characterized in that:

12. A developer; a developer carrier; a developer layer thickness regulating member that contacts the developer carrier and regulates the layer thickness of the developer carried on the developer carrier; a developer containing member that contains the developer; An electrophotographic image forming apparatus having: At least a part of the developer layer thickness regulating member is conductive, a predetermined voltage can be applied to the developer layer thickness regulating member; The developer carrier is a substrate having an electrically conductive outer surface; a resin layer present on the outer surface side of the substrate; and A metal film was provided directly on the outer surface of the developer carrier, and a DC voltage of 50 V was applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%, while an AC voltage of 50 V amplitude was applied at a frequency of 1.0×10 －１ ~1.0 x 10 ５ When applied while changing between 1.0 x 10 Hz, ０ ~1.0 x 10 １ Impedance at Hz is 1.00 x 10 ６ is greater than or equal to Ω, When the ionization potential of the developer is I(T) and the ionization potential of the outer surface of the developer carrier is I(R), I(T) and I(R) satisfy the following formula (X): │I(T)-I(R)│≦0.3eV ...(X) In an environment of 23°C temperature and 50% relative humidity, a corona having a grid part with a width of 3.0 mm was used. a discharger is disposed so that the distance between the grid portion and the outer surface of the developer carrier is 1.0 mm and the width direction of the grid portion coincides with the axial direction of the developer carrier; a voltage of 8 kV is applied to the grid portion; and the corona discharger is moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier; and the maximum value of the potential of the outer surface measured 0.06 seconds after the grid portion has passed is less than 20.0 V. Electrophotographic image forming apparatus characterized in that:

Images