Developing device, process cartridge and electrophotographic image forming apparatus

Abstract

To provide a developing device capable of suppressing the occurrence of ghost images, density unevenness due to toner fusion to a developing roller, and toner transport failure even when the driving torque of the developing device is reduced. [Solution] A developing device having a developing roller and toner, wherein the developing roller has a predetermined configuration, the outer surface of the developing roller is composed of at least a predetermined first region and a second region having higher conductivity than the first region, the first region and the second region are arranged adjacent to each other, the toner has toner particles and microparticles having a compound containing a predetermined metal element, and when the toner surface is measured by X-ray photoelectron spectroscopy, the presence ratio of the metal element is 2.0 to 20.0 atomic %, and the average circularity of the toner is 0.970 or more.

Description

[Technical Field]

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

[0002] In order to increase printing speed, electrophotographic image forming apparatuses (electrophotographic apparatuses) have been improving their performance by increasing process speeds and narrowing the gap between sheets of paper during printing. Furthermore, with the recent increase in environmental awareness, there is a demand for electrophotographic apparatuses to be more energy-efficient. Increasing the process speed of an electrophotographic apparatus increases the drive torque required to drive the electrophotographic apparatus, which tends to increase energy consumption. Therefore, in order to save energy while increasing the process speed, it is necessary to significantly reduce the drive torque of the electrophotographic apparatus.

[0003] The developing device accounts for a large proportion of the driving torque of an electrophotographic device, and the torque generated between the toner supply roller and the developing roller accounts for the majority of that torque. Therefore, reducing the driving torque between the toner supply roller and the developing roller can significantly contribute to increasing process speed and energy conservation. To reduce the driving torque of the developing device, for example, it is possible to reduce the contact area of ​​the toner supply roller with the developing roller, reduce the difference in peripheral speed between the developing roller and the toner supply roller, or eliminate the toner supply roller. However, reducing the contact area of ​​the toner supply roller, reducing the difference in peripheral speed, or eliminating the toner supply roller as described above can reduce the toner supply function of the toner supply roller to the developing roller, which can reduce the amount of toner transported on the developing roller and result in reduced image density.

[0004] To address the issues associated with reducing the drive torque of such developing devices, a developing roller whose outer surface is composed of an insulating portion and a conductive portion has been investigated. When this developing roller is used in an electrophotographic device, the insulating portion of the surface becomes charged due to frictional charging between the developing roller and toner, and due to injection charging, which injects charge due to the potential difference between the developing roller and other contacting members, primarily the developing blade. When the insulating portion becomes charged, a small electric field is formed due to the potential difference between the charged insulating portion and the highly conductive, uncharged conductive portion. This small electric field generates a gradient force around the developing roller, which is a force that attracts the toner to the outer surface of the developing roller. This gradient force attracts the toner around the developing roller to the developing roller, allowing the developing roller to transport a sufficient amount of toner even when the drive torque between the toner supply roller and the developing roller is reduced.

[0005] In addition, if the insulating portion is charged by injection charging, it is less susceptible to factors other than the developing roller, such as the state of the toner, compared to frictional charging, making it possible to ensure a stable toner transport force.

[0006] Furthermore, reducing the contact area of ​​the toner supply roller, reducing the peripheral speed difference, or eliminating the toner supply roller altogether reduces another function of the toner supply roller: recovering undeveloped toner from the developing roller. If toner is no longer recovered from the developing roller, the undeveloped toner on the developing roller is repeatedly rubbed against a contact member such as a developing blade. On the other hand, the toner newly coated on the developed toner area on the developing roller is rubbed against the contact member only once. In this way, the difference in the number of times the toner is rubbed between the developed and undeveloped areas on the developing roller causes a difference in the amount of charge on the toner in each area, resulting in a difference in the amount of charge on the toner. Furthermore, the undeveloped toner deteriorates as it is repeatedly rubbed against the developing roller, and the toner may fuse to the developing roller, resulting in an image with uneven density.

[0007] Patent Document 1 discloses an image forming apparatus in which a developing roller configured with a plurality of dielectric portions scattered on a surface made of a conductive portion and a developing blade are applied so that the potential difference between them is larger during non-image formation than during image formation. By making the potential difference between the developing roller and the developing blade larger during non-image formation than during image formation, the toner on the developing roller is refreshed, thereby improving ghosting, poor solid image tracking, and toner fusion to the developing roller. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-051097 Summary of the Invention [Problem to be solved by the invention]

[0009] However, according to the inventors' investigations, when the image forming device of Patent Document 1 narrows the gap between sheets of paper during printing in order to increase the printing speed, ghost images and toner fusion to the developing roller can occur.

[0010] The present disclosure provides a developing device that can suppress the occurrence of ghost images, density unevenness due to toner fusion to the developing roller, and toner transport defects, even when the driving torque of the developing device is reduced, without relying on control of the potential difference between the developing roller and the developing blade during non-image formation. Another aspect of the present disclosure provides a process cartridge that is detachably mounted to the main body of an electrophotographic image forming apparatus, and that includes the above-mentioned developing device. Yet another aspect of the present disclosure provides an electrophotographic image forming apparatus that includes the above-mentioned process cartridge. [Means for solving the problem]

[0011] The present disclosure provides: A developing device having a developing roller and toner, The developing roller is a substrate having an electrically conductive outer surface; a conductive layer on the outer surface of the substrate; the outer surface of the developing roller is composed of at least a first region and a second region having a higher conductivity than the first region; the first region and the second region are disposed adjacent to each other; the first region is disposed on an outer surface of the conductive layer; The toner includes toner particles and fine particles having a compound containing a metal element, the metal element is at least one element selected from the group consisting of titanium, aluminum, zirconium, and zinc, when the toner surface is measured by X-ray photoelectron spectroscopy, the abundance ratio of the metal element is 2.0 to 20.0 atomic %; The toner has an average circularity of 0.970 or more.

[0012] The present disclosure also provides a process cartridge that is detachably mounted to the main body of an electrophotographic image forming apparatus, the process cartridge including a developing unit, the developing unit having the above-described developing device. A photographic imaging device is provided. [Effects of the Invention]

[0013] According to the present disclosure, a developing device, a process cartridge, and an electrophotographic image forming apparatus are provided that can suppress the occurrence of ghost images, density unevenness due to toner fusion to the developing roller, and poor toner transport even when the driving torque of the developing device is reduced. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. [Figure 2]FIG. 2A is a schematic cross-sectional view showing an example of a developing roller, and FIG. 2B is a schematic view of the outer surface of an example of a developing roller. [Figure 3] FIG. 10 is a schematic cross-sectional view showing another example of the developing roller. [Figure 4] FIG. 2 is a schematic diagram of a process cartridge. [Figure 5] FIG. 1 is a schematic diagram of an electrophotographic image forming apparatus. [Figure 6] FIG. 10 is a schematic diagram showing a state in which a measurement electrode is formed on a developing roller. [Figure 7] FIG. 2 is a cross-sectional view of a developing roller and a measurement electrode. [Figure 8] FIG. 1 is a schematic diagram of an impedance measurement system. [Figure 9] FIG. 1 is a schematic diagram showing an example of an apparatus for measuring the surface potential of a developing roller. [Figure 10] FIG. 10 is a schematic diagram of a circuit for measuring leakage current flowing from the toner to the developing roller. [Figure 11] FIG. 1 is a schematic diagram of an electrophotographic image forming apparatus for image evaluation. DETAILED DESCRIPTION OF THE INVENTION

[0015] 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 lower and upper 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. Note that when XX is a group, multiple XXs may be selected, and the same applies to YY and ZZ.

[0016] The present inventors have speculated as follows why ghost images and toner fusion to the developing roller occur when the gap between sheets of paper is shortened during printing in the image forming apparatus disclosed in Patent Document 1. As the gap between sheets of paper during printing becomes shorter, the non-image-forming interval also becomes shorter. As the non-image-forming interval becomes shorter, it becomes narrower than one revolution of the developing roller. In this case, even if the potential difference between the developing roller and the developing blade during non-image formation is increased compared to during image formation, it is presumed that the toner on the developing roller cannot be sufficiently refreshed. This is thought to have resulted in a difference in the number of times the toner is rubbed between the developed and undeveloped areas of the developing roller, resulting in ghost images and toner fusing to the developing roller after repeated rubbing.

[0017] The inventors thought that if it were possible to replace the toner on the developing roller without relying on controlling the potential difference between the developing roller and the developing blade when no image is being formed, ghost images and toner fusion could be suppressed regardless of the distance between the sheets of paper, even if the driving torque of the developing device was reduced. Specifically, by controlling the charge series between the toner and the contacting member such as the developing roller or the regulating member, the charge is removed from the toner when the contacting member and the toner rub against each other, and the non-electrostatic adhesion force is reduced. However, the above method does not provide the toner necessary to obtain normal image quality. In addition, when the developing roller is used for a long period of time in an environment where toner components are likely to adhere to each contacting member, such as a low-temperature, low-humidity environment, the surface properties of each contacting member change, changing the relationship between the toner and the charge series, making it difficult to maintain a balance between the charge applied to the toner and the charge removed from the toner.

[0018] That is, the inventors recognized that in order to obtain excellent image quality while realizing a reduction in the drive torque of the developing device, an increase in printing speed, and long-term use, a new solution that does not rely on bias control during non-image formation or control of the triboelectric series between the toner and the contact member is necessary. Based on this recognition, the inventors conducted further research.

[0019] As a result, the present inventors have come to recognize that the developing device of the present disclosure is effective as a solution to the above problem. The present disclosure provides: A developing device having a developing roller and toner, The developing roller is a substrate having an electrically conductive outer surface; a conductive layer on the outer surface of the substrate; the outer surface of the developing roller is composed of at least a first region and a second region having a higher conductivity than the first region; the first region and the second region are disposed adjacent to each other; the first region is disposed on an outer surface of the conductive layer; The toner includes toner particles and fine particles having a compound containing a metal element, the metal element is at least one element selected from the group consisting of titanium, aluminum, zirconium, and zinc, when the toner surface is measured by X-ray photoelectron spectroscopy, the abundance ratio of the metal element is 2.0 to 20.0 atomic %; The toner has an average circularity of 0.970 or more.

[0020] The inventors speculate that the reason why the developing device, which satisfies the above requirements, can suppress ghost images and density unevenness caused by toner fusion without controlling the bias during non-image formation or the charge series between the toner and the contact member, is as follows. The first reason is that charge transfer between toner particles is facilitated. The toner according to the present disclosure comprises toner particles and microparticles having a compound containing a metal element, and the metal element is at least one element selected from the group consisting of titanium, aluminum, zirconium, and zinc. In addition, when the toner surface is measured by X-ray photoelectron spectroscopy, the abundance ratio of the metal element is 2.0 to 20.0 atomic %. This appropriately reduces the conductivity of the toner in the surface direction, making charge transfer easier when toner particles come into contact with each other.

[0021] The second reason is that the toner transported on the developing roller tends to roll when it comes into contact with the toner in the developing device and is subjected to shearing force. In order for the toner on the developing roller to roll due to shearing force, the toner needs to be spherical enough to roll, and have enough adhesive strength to prevent slippage between the toner and the developing roller. First, when the average circularity of the toner is 0.970 or more, the toner becomes spherical enough to roll, and the toner easily rolls when a shear force is applied to the toner.

[0022] Furthermore, the developing roller has a first region and a second region that are arranged adjacent to each other on the outer circumferential surface and have higher conductivity than the first region. The first region is an insulating portion, and the second region is a conductive portion. By using such a developing roller, a gradient force, which is a force in a direction that attracts to the developing roller surface, is generated near the surface of the developing roller. Gradient The ent force is relatively small compared to the image force, and acts as an appropriate adhesive force, making it easier for the toner to roll on the developing roller without slipping between the toner and the developing roller. By rolling the toner on the developing roller, the contact area between the toner on the developing roller and the toner in the developing device increases significantly compared to when there is no rolling. In addition, the occurrence of toner transport problems is suppressed.

[0023] For these two reasons, namely, the ease with which toner particles exchange charge with each other and the ease with which toner particles roll on the developing roller, increasing the contact area between toner particles, charge exchange occurs rapidly between the charged toner on the developing roller and the uncharged toner in the developing device. As a result, the charge on the toner on the developing roller rapidly decreases, and the adhesive force between the developing roller and the toner rapidly decreases. As a result, the toner on the developing roller is peeled off from the developing roller by shear force and centrifugal force caused by the rotation of the developing roller, and new toner in the developing container is attracted to the developing roller by gradient force. In other words, the toner on the developing roller is spontaneously replaced as it passes through the developing device.

[0024] In this way, by combining the developing roller and toner according to the present disclosure, it is possible to spontaneously replace the toner on the developing roller without relying on bias control during non-image formation or control of the charge series between the toner and the contact member. As a result, it is believed that it is possible to suppress the occurrence of the ghost images and images with uneven density due to toner fusion to the developing roller, and to suppress the occurrence of toner transport problems.

[0025] The present disclosure will be described in detail below. <Developing device> The developing roller according to the present disclosure includes a developing roller and toner. An example of a cross-sectional view of a developing device according to the present disclosure is shown in FIG. 1. The developing device 18 is filled with toner 16. The toner 16 is supplied to the surface of the developing roller 14 by a toner supply roller 17, or is attracted to the developing roller 14 by gradient force, and a layer of toner 16 of a predetermined thickness is formed on the surface of the developing roller 14 by a developing blade 15.

[0026] <Developing roller> The developing roller has a substrate having a conductive outer surface and a conductive layer on the outer surface of the substrate. The outer surface of the developing roller is further composed of at least a first region (insulating portion) and a second region (conductive portion) having a higher conductivity than the first region, the first region and the second region being disposed adjacent to each other, and the first region being disposed on the outer surface of the conductive layer.

[0027] FIG. 2A shows an example of a schematic cross-sectional view of a developing roller, and FIG. 2B shows an example of a schematic outer surface view. The developing roller 10 shown in FIG. 2A has a conductive layer 12 laminated on the outer surface of a cylindrical or hollow cylindrical substrate 11. The outer surface of the developing roller is further composed of a first region 1 and a second region 2 having higher conductivity than the first region, and the second region 2 is composed of the outer surface of the conductive layer 12. The first region 1 is composed of the outer surface of an insulator arranged on the outer surface of the conductive layer 12 so that the outer surface of the conductive layer is exposed. The first region may be formed by arranging an insulator on the outer surface of the conductive layer 12, or by exposing an insulator contained in the conductive layer 12.

[0028] The layer configuration of the developing roller is not limited to the form shown in Fig. 2A. Another form of the developing roller is a developing roller having an elastic layer 13 between a base 11 and a conductive layer 12 provided on the outer circumferential surface thereof, as shown in Fig. 3.

[0029] Furthermore, it is preferable that the developing roller satisfy the following two requirements, since this can further suppress the occurrence of ghost images and density unevenness while suppressing toner transport defects.

[0030] Requirement (1) A metal film was provided directly on the outer surface of the developing roller, 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 1.0×10 6 It is greater than or equal to Ω.

[0031] Requirement (2) In an environment of 23°C temperature and 50% relative humidity, a corona discharger having a grid portion with a width of 3.0 mm was placed so that the distance between the grid portion and the outer surface of the developing roller was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developing roller, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developing roller at a speed of 400 mm / sec to charge the outer surface of the developing roller, and the potential of the outer surface was measured t seconds after the grid portion had passed. The potential at t=0.06 [seconds] is V INI [V], The change in potential in the range of 30.00≦t≦100.00 was fitted to the following equation (X′) by the least squares method, and V 0,1 When [V] and τ1 [seconds] are calculated, when t = 0.06 [seconds] is substituted into the formula (X'), the value of the potential V1(t) is V1 [V], INI -V1 is less than 20.0V. V1(t)=V 0,1 exp(-t / τ1) (X')

[0032] The above requirements (1) and (2) are explained in detail below. (Technical significance of requirement (1)) Requirement (1) specifies the value of the impedance of the developing roller. This impedance is a physical property that indicates the charge leakage from the toner to the second region, i.e., the conductive portion, that constitutes the outer surface of the developing roller. The inventors measured the current value (leakage current value) that flows through the developing roller when a blade bias is applied to the developing blade according to the circuit diagram shown in FIG. 10. As a result, it was found that this current value exhibits a higher correlation with the impedance value of the developing roller than the electrical resistance value of the developing roller. Furthermore, it was found that when the outer surface of the developing roller is composed of an insulating portion (first region) and a conductive portion (second region), the above impedance value exhibits the characteristics of the conductive portion, which has higher conductivity. In other words, this shows that when it comes to charge leakage, it is necessary to consider not only the resistance component of the developing roller (conductive part), but also the influence of the capacitance component.This is thought to be because, when the electrical characteristics of the developing roller are represented pseudo-analogously as an RC parallel circuit, the transient state until a sufficient amount of charge is stored in the capacitance component and the steady state dominated by the resistance component has a large influence on charge leakage.

[0033] The voltage application conditions for measuring impedance were a DC voltage of 50 V superimposed on an AC voltage of 50 V. In other words, a sine wave with minimum and maximum applied voltages of 0 V and 100 V (Vpp100 V) was applied. This value of Vpp100 V is the assumed maximum value of the shared voltage applied to the developing roller when a voltage is applied so that a voltage difference of 300 V is applied between the developing roller and developing blade in an electrophotographic image forming apparatus.

[0034] 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 developing roller. In conventional impedance measurements of developing rollers, an AC voltage of 1 V is generally used as the voltage application condition, but this AC voltage of 1 V is clearly smaller than the voltage (generally several hundred volts) applied between the developing roller and developing blade in an actual electrophotographic image forming apparatus. Therefore, it is often not possible to simulate the behavior of the developing roller in an electrophotographic image forming apparatus, and it is 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.

[0035] 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 1The 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 toner to the conductive part. 0 ~1.0×10 1 Impedance at Hz is 1.0×10 6 When the resistance is Ω or more, the charge leakage from the conductive layer is low, and charge leakage from the toner to the conductive layer under a high blade bias is easily suppressed. The toner according to the present disclosure has low resistance in the surface direction, and charge is easily injected from the development blade. Furthermore, because charge leakage to the conductive layer is suppressed, charge is easily imparted quickly to toner with a low charge amount after it is replaced from the development roller. This makes it less likely that differences in charge amount of toner on the development roller will occur, making it easier to suppress ghost images.

[0036] The frequency is 1.0 x 10 0 ~1.0×10 1 The impedance at Hz is preferably 1.4 x 10 6 The higher the impedance value, the better. There is no particular upper limit, but for example, 5.0 × 10 7 Examples include Ω and below. Also, the frequency is 1.0×10 0 ~1.0×10 1 The impedance at Hz is preferably 1.4 x 10 6 Ω or more, more preferably 2.0×10 6 Ω or more, particularly preferably 3.0 × 10 6 Ω or more, more preferably 5.0×10 6 The preferred range of the impedance is 1.0×10 6 Ω or more 5.0×10 7 Ω or less, preferably 1.4×10 6 Ω or more 5.0×10 7 Ω or less, more preferably 2.0×10 6 Ω or more 5.0×10 7 Ω or less, particularly preferably 3.0 × 10 6 Ω or more 5.0×107 Ω or less, more preferably 5.0 × 10 6 Ω or more 5.0×10 7 It is less than Ω.

[0037] (Technical significance of requirement (2)) Requirement (2) specifies the surface potential of the outer surface of the developing roller. This surface potential corresponds to the surface potential of the conductive portion, which is the second region. The surface potential of the conductive portion indicates how easily the charge in the conductive portion remains. The higher this surface potential, the more difficult it is to remove the charge injected into the conductive portion. As a result, the potential difference between the conductive portion and the insulating portion decreases, i.e., the gradient force decreases, causing poor toner transport and making it difficult for the toner on the developing roller to roll.

[0038] In this disclosure, when a voltage of 8 kV is applied to the grid portion and the corona discharger is moved relative to the developing roller in the axial direction at a speed of 400 mm / s, the decay behavior of the potential on the outer surface of the developing roller after the grid portion of the corona discharger has passed, i.e., the relaxation curve, is confirmed. The relaxation curve of the surface potential of a developing roller whose outer surface is composed of conductive and insulating parts is a curve that combines a relaxation curve corresponding to the conductive parts, which decay quickly, and a relaxation curve corresponding to the insulating parts, which decay slowly. The relaxation curve is generally expressed by the following formula (X): V=V0exp(-t / τ) (X) In formula (X), V0 represents the surface potential [V] at t=0, t represents the elapsed time [seconds], and τ represents the time constant. In addition, the surface potential of the developing roller in the range of 30.00≦t≦100.00 is considered to be less affected by the relaxation curve corresponding to the conductive part with fast decay. Therefore, the change in the surface potential of the developing roller in the range of 30.00≦t≦100.00 is fitted to the following formula (X'), and V 0,1 When the values ​​of [V] and τ1 [seconds] are calculated, V1(t) is the outer surface of the developing roller. This relaxation curve corresponds to an area where charge decay is slow on the surface, i.e., an insulating portion. V1(t)=V 0,1 exp(-t / τ1) (X') In formula (X'), V 0,1 indicates the surface potential [V] of the insulating part at t=0, and τ1 indicates the time constant [seconds] of the insulating part. Therefore, when t=0.06 is substituted into the potential V1(t), the value V1 represents the surface potential of the insulating part 0.06 seconds after the grid part of the corona discharger has passed.

[0039] On the other hand, V INI is the measured value of the surface potential of the outer surface of the developing roller, including the conductive and insulating parts, 0.06 seconds after the grid part of the corona discharger has passed. In other words, the surface potential of the conductive part 0.06 seconds after the grid part of the corona discharger has passed is V INI -V1. If the surface potential of the conductive portion is less than 20.0 V, the charge injected into the conductive portion when passing through a contacting member such as a developing blade or photosensitive drum can be quickly removed. Therefore, even when the conductive portion repeatedly passes through the developing blade or photosensitive drum due to the rotation of the developing roller, charge does not accumulate on the conductive portion, and the potential difference between the conductive portion and the insulating portion does not decrease, resulting in a stable gradient force. This makes it easier to suppress toner transport problems. Furthermore, the toner on the developing roller can more easily roll, facilitating the exchange of charge between the toner on the developing roller and the toner in the developer container, thereby making it easier to suppress ghost images and density unevenness.

[0040] The time 0.06 seconds after the grid of the corona discharger passes simulates the time it takes for the conductive part of the developing roller to reach the contact position with another contact member, such as the photosensitive drum, after the developing blade has passed in a model with a high process speed. This prevents charge from accumulating on the conductive part even when frictional charging or injection charging occurs not only with the developing blade but also with the photosensitive drum, making it easier to suppress poor toner transport, ghost images, and uneven density images in electrophotographic image forming devices with high process speeds. The surface potential of the conductive part (V INI−V1) is preferably 15.0 V or less, and more preferably 10.0 V or less. The lower the maximum value of the potential of the outer surface, the better, and there is no particular lower limit. The surface potential of the conductive portion is, for example, preferably 0.0V or more and less than 20.0V, particularly preferably 0.0V or more and 15.0V or less, and further preferably 0.0V or more and 10.0V or less.

[0041] [Base] The substrate is electrically conductive and functions as a support member for the developing roller and, in some cases, as an electrode. Specific examples of the substrate include a solid columnar shape and a hollow cylindrical shape.

[0042] The material for the substrate can be appropriately selected from those known in the field of electroconductive members for electrophotography and materials usable for such developing rollers, and examples thereof include metals or alloys such as aluminum and stainless steel, carbon steel alloys, conductive synthetic resins, iron, and copper alloys.

[0043] 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.

[0044] A primer may be applied to the surface of the substrate to improve adhesion between the substrate and the conductive layer or elastic layer. The primer is suitable for the rubber material for forming the conductive layer and the material of the support. A known material can be selected and used accordingly. Examples of the primer material include thermosetting resins and thermoplastic resins, and specific examples of materials that can be used include phenolic resins, polyurethanes, acrylic resins, polyester resins, polyether resins, and epoxy resins.

[0045] [Conductive layer and second region (conductive portion)] The developer roller has a conductive layer on the outer surface of a substrate, and the outer surface of the developer roller is configured with at least a first region and a second region having a higher conductivity than the first region. That is, the conductive layer is provided on the outer surface of the substrate, and the second region (conductive portion) that constitutes the outer surface of the developing roller is constituted by the outer surface of the conductive layer. The conductive layer may contain a binder resin.

[0046] (binder resin) The binder resin of the conductive layer is preferably polyurethane from the viewpoints of durability, flexibility, and electrical properties as a surface layer. That is, the conductive layer preferably contains polyurethane. Examples of such polyurethane include polyurethane having a polyether structure, polyurethane having a polyester structure, and polyurethane having a polycarbonate structure. Among these, it is more preferable to use polyurethane having a polycarbonate structure in order to suppress charge leakage from the toner to the conductive layer, that is, it is more preferable that the conductive layer contains polyurethane having a polycarbonate structure.

[0047] Furthermore, in order to suppress charge leakage from the insulating portion to the conductive layer while maintaining sufficient flexibility of the conductive layer to reduce the load on the toner and sufficient abrasion resistance of the conductive layer, it is more preferable to use a polyurethane having the structure described below as the binder resin of the conductive layer.

[0048] The conductive layer contains polyurethane, and the polyurethane preferably satisfies at least two of the following (A), (B), and (C). It 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, in its molecule, either one or both of a structure represented by the following structural formula (2) and a structure represented by the following structural formula (3): (C) The polyurethane has a structure represented by the following structural formula (4) in the molecule.

[0049] 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) [ka]

[0050] 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 (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).

[0051] 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 conductive layer flexibility and high volume resistivity. By using the structure of structural formula (1) in combination with the structures (2) to (4) described above in the conductive layer, the adhesiveness of the conductive layer can be reduced, which prevents toner, powder, etc. from adhering to the surface of the conductive layer, prevents an increase in the electrical resistance of the surface of the conductive layer due to contamination, and makes it easier to quickly remove the charge injected into the conductive portion.

[0052] 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 is not too large, making the conductive layer flexible and highly conductive. This makes it easier to maintain the resistance value. 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 conductive 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.

[0053] 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 conductive layer.

[0054] When a conductive 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 conductive layer can be given sufficient volume resistivity while having a polar ester group, making it easier to suppress charge leakage from the toner to the conductive layer.

[0055] 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 and ester groups in the polyurethane, which are polar functional groups with strong cohesive energy, is not too large, allowing the conductive layer to maintain flexibility. When R31 and R32 each have 8 or less carbon atoms, the amount of carbonate and ester groups in the polyurethane is not too small, allowing the conductive layer to be imparted with abrasion resistance.

[0056] 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 arranged in the soft segment, which can impart abrasion resistance and high volume resistivity to the conductive layer. By forming a conductive layer using a polymer in which the structure represented by structural formula (4) is combined with the structures of formulas (1) to (3) above, the hardness of the conductive layer does not become too high and can be easily controlled appropriately.

[0057] 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 conductive 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 conductive layer can be suppressed.

[0058] The conductive layer preferably contains a polymer having a urethane bond, i.e., polyurethane, as a binder resin, and the polymer preferably satisfies at least two selected from the group consisting of (A), (B), and (C), thereby making the conductive layer flexible and less susceptible to wear.

[0059] The structure of the polymer contained in the conductive layer of the developing roller can be confirmed by, for example, pyrolysis GC / MS, FT-IR, or NMR analysis.

[0060] Polyurethane can be produced using (A) a polyol compound and (B) a polyisocyanate compound. Polyurethane is usually synthesized by the following methods (1) and (2). (1) One-shot method in which the polyol component and the polyisocyanate component are mixed and reacted (2) A method of reacting an isocyanate-terminated prepolymer obtained by reacting a part of a polyol with an isocyanate with a chain extender such as a low molecular weight diol or low molecular weight triol.

[0061] In the present disclosure, polyurethane may be synthesized by any of the above methods, but 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 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 conductive layer. The polyurethane is more preferably a reaction product of a mixture containing a hydroxyl-terminated prepolymer, an isocyanate-terminated prepolymer, a conductive filler, and an additive.

[0062] When the polyurethane contains a large number of hydroxyl groups, isocyanate groups, or urea bonds, allophanate bonds, isocyanurate bonds, etc., the amount of polar functional groups present in the polyurethane increases, which may result in an increase in the water absorption of the polymer and a decrease in the volume resistivity of the conductive layer. On the other hand, by thermally curing the hydroxyl-terminated prepolymer and the isocyanate-terminated prepolymer, a polyurethane with less unreacted polyol and polar functional groups can be obtained without using an excessive amount of isocyanate. This is therefore preferable from the viewpoint of further suppressing charge leakage from the toner to the conductive layer.

[0063] (A) Polyol compound The polyol compound may be any polyol known for or usable in the synthesis of urethane resins. 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, and polyester-polycarbonate copolymer polyols. Among these, the polyol compound is preferably at least one selected from the group consisting of polycarbonate polyols and polyester polycarbonate copolymer polyols.

[0064] 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.

[0065] 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.

[0066] (B) Polyisocyanate compound The polyisocyanate may be selected from commonly used known ones, such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymeric diphenylmethane polyisocyanate, hydrogenated MDI, polymeric MDI, xylylene diisocyanate (XDI), and hexamethylene diisocyanate. (HDI), isophorone diisocyanate (IPDI), etc. Among these, aromatic isocyanates such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymeric diphenylmethane polyisocyanate, and polymeric MDI are more preferably used.

[0067] 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.

[0068] The content of polyurethane in the conductive layer is not particularly limited, but is preferably 50 to 95% by mass, more preferably 60 to 80% by mass, and even more preferably 65 to 75% by mass.

[0069] (Conductive filler) The conductive 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 conductive 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 conductive layer, a DBP absorption of 90 ml / 100 g or less, and a pH of 4.0 or less is particularly preferably used.

[0070] 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, and the structure (the size of the particle connections) also becomes small, making it difficult to form conductive paths. As a result, 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] The carbon black content is preferably added so as to achieve 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 polyurethane forming the conductive 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 conductive layer formed from the coating liquid.

[0077] To achieve the above-mentioned specific impedance and surface potential, it is preferable to control the dispersion of the carbon black. As for the particle size of the dispersed carbon black, the arithmetic mean value Rc of the equivalent circle diameter of the carbon black in the conductive layer is preferably 60.0 nm or less. Furthermore, when the standard deviation of the equivalent circle diameter is σc [nm], it is more preferable that σc / Rc is 0.000 to 0.650. Furthermore, as for the distance between the carbon black particles, it is more preferable that the arithmetic mean value d of the distance between the wall surfaces of the carbon black particles in the conductive layer is 80.0 to 150.0 nm, and σd / d is 0.000 to 0.600, where σd [nm] is the standard deviation of the distance between the wall surfaces.

[0078] 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 and increasing resistance, resulting in higher impedance. Regarding surface potential, localized charge accumulation is less likely to occur, making it possible to lower the surface potential. Incidentally, multiple types of carbon black may be used in combination.

[0079] The arithmetic mean value Rc of the equivalent circle diameter is more preferably 40.0 to 60.0 nm, and even more preferably 45.0 to 55.0 nm. σc / Rc is more preferably 0.500 to 0.650, and even more preferably 0.550 to 0.650. 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 conductive 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.

[0080] The arithmetic mean value d of the distance between the wall surfaces is more preferably 90.0 to 120.0 nm, and even more preferably 95.0 to 115.0 nm. σd / d is more preferably 0.500 to 0.600, and even more preferably 0.540 to 0.590. 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 conductive 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.

[0081] (additives) One preferred embodiment is to use 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. That is, the conductive layer preferably contains at least one compound selected from the group consisting of a compound represented by the following structural formula (5), a compound represented by the following structural formula (6), and a compound represented by the following structural formula (7). One method for incorporating the additive into the conductive layer is to incorporate a dispersant into the coating liquid for forming the surface layer. In a surface layer formed using a coating liquid for forming a surface layer containing at least one compound selected from the group consisting of a compound having a structure represented by structural formula (5) and a compound having a structure represented by structural formula (6), the compound may be incorporated into the end of the polyurethane polymer chain. Even in such a case, the effect of improving the dispersibility of carbon black can be expected, but it is preferable that the compound be present in the surface layer independently of the polyurethane.

[0082] 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]

[0083] 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 1.0 or more (preferably 5.0 to 30.0, more preferably 10.0 to 25.0). 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 1.0 or more (preferably 1.0 to 30.0, more preferably 5.0 to 30.0). 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 is a number of 1.0 or more (preferably 1.0 to 30.0, more preferably 4.0 to 15.0).

[0084] 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.

[0085] 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 conductive layer. This is thought to be because the side-chain methyl group of propylene oxide interacts with the conductive filler, improving the dispersibility of the conductive filler.

[0086] 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 mono-ol structure, it is less reactive than a diol and is less likely to be incorporated into the urethane reaction caused by the reaction of isocyanate with a polyol, which makes it less likely to lead to a decrease in the resistance of the polyurethane due to the introduction of an ether structure into the polycarbonate urethane.

[0087] 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).

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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).

[0094] 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 to produce a ketone by oxidation of a secondary alcohol. The synthesis of a ketone by oxidation of a secondary alcohol is carried out using heavy metal salts such as chromic acid and manganese dioxide and their There are two types of oxidation reactions: oxidation reactions using derivatives and oxidation reactions using non-heavy metal salts using dimethyl sulfoxide (DMSO) or hypohalous acids such as hypochlorous acid.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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).

[0100] Step (F) is a step in which a primary alcohol is oxidized to produce a carboxylic acid. In the oxidation of a primary alcohol, an aldehyde is produced, and then a carboxylic acid is produced by further oxidation. Therefore, it is necessary to select a reaction method and conditions that do not stop at the aldehyde. Methods for obtaining a carboxylic acid by oxidation of a primary alcohol include oxidation with an oxidizing agent and oxidation with a catalyst. Catalytic dehydrogenation is one example. Oxidizing agents include permanganate, chromic acid, ruthenium tetroxide, and hypochlorite. Dehydrogenation catalysts include palladium, platinum, iridium, rhodium, and manganese.

[0101] 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.

[0102] 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.

[0103] The amount of the compounds represented by structural formulas (5) to (7) added is preferably 3.0 to 7.0 mass % based on the solid content in the conductive layer-forming coating liquid, more preferably 3.0 to 5.0 mass %, and the total content is preferably 18.9 to 46.0 mass parts per 100 mass parts of carbon black in the conductive layer-forming coating liquid. By keeping the content of the additive in the conductive layer-forming coating liquid within the above range, the dispersibility of carbon black in polyurethane is further improved, and the desired impedance value and surface potential can be more easily achieved.

[0104] The presence of the additive in the conductive layer can be confirmed and quantitatively evaluated by the following method. The conductive layer of the developing roller is cut out, and the cut piece is subjected to, for example, 1 H-NMR, 13 Analysis is performed using CNMR, XPS, and FT-IR. This allows the carbonate structure of the binder resin, and the ether structure, amine structure, and carboxylic acid structure of the additives to be detected in the conductive layer, and the ratio can be calculated from the peak ratios, 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 Analysis using C-NMR, XPS, and FT-IR is performed, which allows us to calculate the proportion of additives that have been incorporated into the resin during the polymerization reaction and those that have not.

[0105] The conductive layer may have a structure in which at least one of the compounds having the structures represented by structural formulas (5) and (6) is bonded to polyurethane (a structure resulting from a reaction during polyurethane polymerization). Examples of the structure resulting from a reaction during polyurethane polymerization 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.

[0106] (roughening particles) The conductive layer may contain roughening particles. The roughening particles 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 150 μm. It is more preferable that the particle size is in the range of 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 conductive layer is preferably 1 to 50 mass %, more preferably 5 to 30 mass %.

[0107] (Conductive layer manufacturing method) The method for forming the conductive layer is not particularly limited, but examples include spraying, dip coating, and roll coating. For example, a conductive layer can be formed by applying a conductive layer-forming coating liquid to the substrate or an elastic layer formed on the outer surface of the substrate using a known method, and then heating and drying the applied coating liquid. The conditions for heating and drying are not particularly limited, and examples include methods in which the conductive layer is dried at temperatures of 120 to 200°C. The thickness of the conductive layer is also not particularly limited, and is preferably 1 to 50 μm, and more preferably 5 to 20 μm.

[0108] (Time constant of the surface potential of the conductive part) It is preferable that the time constant of the surface potential of the conductive portion is 6.0 seconds or less, since the charge injected into the conductive portion can be easily and quickly removed. Specifically, in an environment of a temperature of 23°C and a relative humidity of 50%, a corona discharger having a grid portion with a width of 3.0 mm was placed so that the distance between the grid portion and the outer surface of the developing roller was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developing roller, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developing roller at a speed of 400 mm / sec to charge the outer surface of the developing roller, and the potential of the outer surface was measured t seconds after the grid portion had passed. The change in potential in the range of 0.06≦t≦100.00 was fitted to the following equation (Y) by the least squares method, and V 0,2 When [V] and τ2 [seconds] are calculated, τ2 is preferably 6.0 seconds or less. τ2 is more preferably 5.0 seconds or less, and even more preferably 4.0 seconds or less. There is no particular lower limit, and τ2 may be in the range of, for example, 0.1 to 6.0 seconds, 0.1 to 5.0 seconds, or 0.1 to 4.0 seconds. V(t)=V1(t)+V2(t) (Y) In formula (Y), V2(t)=V 0,2 exp(-t / τ2) (Z)

[0109] As mentioned above, V1(t) represents the relaxation curve corresponding to the insulating portion. The change in potential in the range of 0.06≦t≦100.00 also includes the influence of the relaxation curve corresponding to the conductive portion, which decays quickly. Therefore, V2(t) in the above formula (Y) obtained by fitting the change in potential in the range of 0.06≦t≦100.00 represents the relaxation curve corresponding to the conductive portion. Therefore, V 0,2 is the surface potential of the conductive part at t = 0, and τ2 is the time constant of the surface potential of the conductive part. V 0,2 The detailed measurement conditions for τ and τ2 will be described later. The time constant of the surface potential of the conductive portion can be controlled by blending a binder resin and a conductive filler.

[0110] [First area (insulation)] The first region (insulating portion) is disposed on the outer surface of the conductive layer. The first region is, for example, configured by the outer surface of an insulator exposed on the outer surface of the conductive layer. The first region may, for example, be scattered on the conductive layer, or may be connected to the conductive layer (second region) so that the conductive layer (second region) is exposed.

[0111] A square observation area with a side length of 300 μm was placed on the outer surface of the developing roller in the axial direction of the developing roller. When the developing roller is placed so that one side of the observation area is parallel to the first area, the ratio of the total area of ​​the first area to the area of ​​the square observation area is preferably 10 to 60 area%, more preferably 15 to 50 area%, and even more preferably 20 to 40 area%, from the viewpoint of imparting an appropriate gradient force to the developing roller. The proportion of the total area of ​​the first region can be controlled by the wettability of the constituent material solution of the first region, the viscosity of the solution, the drying speed, the surface roughness of the conductive layer, the solid content of the solution, and the like.

[0112] The height of each insulating portion from the contact portion with the conductive layer is preferably 0.1 to 10.0 μm. By making this height 0.1 μm or more, the first region can easily attract toner when it is charged. By making this height 10.0 μm or less, the toner can easily be charged between the first region and the contact member. The ratio of the total area and the height of the first region can be measured using, for example, a laser microscope (product name: VK-X100, manufactured by Keyence Corporation). Specific details will be described later.

[0113] (Surface potential of insulating part) In an environment of 23°C temperature and 50% relative humidity, a corona discharger having a 3.0 mm wide grid portion was placed so that the distance between the grid portion and the outer surface of the developing roller was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developing roller. A voltage of 8 kV was applied to the grid portion and the corona discharger was moved relatively along the axial direction of the developing roller at a speed of 400 mm / sec to charge the outer surface of the developing roller. When the potential of the outer surface was measured t seconds after the grid portion had passed, The potential change for 30.00 ≦ t ≦ 100.00 seconds was fitted to the above equation (X') by the least squares method, and V 0,1 When [V] and τ1 [seconds] are determined, it is preferable that τ1 is 60.0 seconds or more.

[0114] It is preferable that the time constant (τ1) of the surface potential of the insulating part is 60.0 seconds or more, because the charge injected into the insulating part is difficult to remove and the insulating part is quickly charged. By quickly charging the insulating part, the potential difference with the conductive part becomes clear from the start of printing, making it easier to demonstrate toner transport power. τ1 is more preferably 100.0 seconds or more, and even more preferably 1000.0 seconds or more. There is no particular upper limit to τ1, but the range of τ1 may be 60.0 to 5000.0 seconds, 100.0 to 4500.0 seconds, or 1000.0 to 4000.0 seconds. τ1 can be adjusted by using the following materials and adjusting the blending amounts thereof, for example. The detailed measurement conditions for τ1 will be described later.

[0115] In addition, in an environment of 23°C temperature and 50% relative humidity, a corona discharger having a 3.0 mm wide grid portion was placed so that the distance between the grid portion and the outer surface of the developing roller was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developing roller, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developing roller at a speed of 400 mm / sec to charge the outer surface of the developing roller, and the potential of the outer surface was measured t seconds after the grid portion had passed. The change in potential at 30.00≦t≦100.00 was fitted to the above equation (X') by the least squares method, and V 0,1 When calculating [V] and τ1 [seconds], if the value of the potential V1(t) when t = 0.06 [seconds] is substituted into formula (X') is V1 [V], it is preferable that V1 is 5.0 V or more. By having a surface potential of 5.0 V or higher immediately after being charged by a corona discharger, the gradient force required to transport the toner is easily exerted when a charge is injected into the insulating portion. V1 is more preferably 6.0 V or higher, and even more preferably 10.0 V or higher. There is no particular upper limit for V1, but V1 may be in the range of 5.0 to 35.0 V, 6.0 to 33.0 V, or 10.0 to 20.0 V. To achieve the above τ1 and V1, the volume resistivity of the insulating part must be 1.0×10 13 Ω cm or more 1.0×10 18 It is preferable that the resistance is Ω·cm or less, and 1.0×10 14 Ω cm or more, 1.0×10 17 It is more preferable that the resistivity is Ω·cm or less. The volume resistivity of the insulating portion can be adjusted by using, for example, the following materials and adjusting the blending amounts thereof.

[0116] (Materials that make up the insulating part) Various electrically insulating materials can be used as the material for the insulating portion. Furthermore, it is preferable that the material be relatively resistant to cracking when the developing member is deformed by contact with another member. Specific examples include inorganic materials such as metal oxides such as silicon dioxide and aluminum oxide, and diamond. Other examples include resins such as polyethylene, polystyrene, polycarbonate, polyacrylic, polytetrafluoroethylene, phenolic resin, urea resin, silicone resin, and polyimide resin. Resins such as polystyrene, polycarbonate, polyacrylic, polytetrafluoroethylene, silicone resin, and polyimide resin, as well as copolymers of these resins, are particularly preferred because they have high electrical resistance, are resistant to cracking even with slight deformation, and are resistant to friction.

[0117] (Method of forming the first region) The method for forming the first region that becomes the insulating portion is not particularly limited, and the following methods can be used, for example. Examples include a method in which an insulating portion-forming coating liquid, prepared by diluting an insulating material in a solvent, is applied to the conductive layer in an island pattern using screen printing, a jet dispenser, or the like, and then the solvent is dried and solidified. Another example includes a method in which the insulating portion-forming coating liquid is uniformly applied to the conductive layer by dipping or the like, and then repelled to expose the conductive layer by controlling the wettability, and then the solvent is dried and solidified. Another example includes a method in which an insulating portion-forming coating liquid containing the insulating material raw material is applied to the conductive layer in an island pattern using screen printing, a jet dispenser, or the like, and then the insulating material raw material is cured by heating or ultraviolet irradiation, as necessary. Another example includes a method in which an insulating portion-forming coating liquid containing the insulating material raw material is uniformly applied to the conductive layer by dipping or the like, and then repelled to expose the conductive layer by controlling the wettability, and then the insulating material raw material is cured by heating or ultraviolet irradiation, as necessary. As a method for controlling the wettability, for example, a method of adding a surface conditioner to the conductive layer can be used.

[0118] [Elastic layer] The developing roller may have an elastic layer on the outer surface of the substrate. The developing roller has the elastic layer between the substrate and the conductive layer, for example. The elastic layer is not particularly limited, and any known elastic layer for developing rollers may be used. For example, a cured product of an addition-curing liquid silicone rubber mixture may be used.

[0119] [Developing roller impedance] In measuring the impedance of a developing roller, the response of the developing roller is examined when AC and DC voltages are applied while changing the frequency. An AC voltage is applied and measurements are taken of two responses: one with no phase shift 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 Z" (imaginary part), and the distance from the origin to the plot is calculated as the impedance value. When the electrical characteristics of the developing roller are expressed pseudo-wise using 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 meaning of the measurement conditions and measured values ​​was explained above in <Technical significance of requirement (1)>, so it will not be explained here.

[0120] The method, device and conditions for measuring the impedance of the developing roller will be described below. (Method for measuring the impedance of the developing roller) The impedance of the developing roller 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 developing roller and measurement is performed using two terminals: the electrode and the substrate. (2) A method in which the developing roller is pressed against a metal drum with a constant load and measured at two terminals, one on the metal drum and the other on the base.

[0121] Although impedance can be measured by either method, method (2) is affected by the nip width and contact area between the developing roller and the metal drum, so it is necessary to measure using a developing roller with the same hardness. Therefore, in this disclosure, measurement is performed using method (1). Measurement method (1) will be described below, but more specific conditions will be described later. When measuring impedance, in order to eliminate the influence of contact resistance between the developing roller and the measurement electrode, it is preferable to deposit a low-resistance thin film on the surface of the developing roller, use the thin film as an electrode, and measure the impedance using two terminals, with the conductive substrate as a ground electrode.

[0122] 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 developing roller, a method of forming a metal thin film such as platinum or palladium as an electrode by deposition is preferred. In the present disclosure, vacuum platinum deposition is used.

[0123] When forming a metal thin film on the surface of a developing roller, in consideration of the ease of the process and the uniformity of the thin film, it is preferable to use a vacuum deposition apparatus that is provided with a mechanism that can grip the developing roller, and that is further provided with a rotation mechanism for a developing roller that has a cylindrical cross section.

[0124] It is preferable to form a thin metal film electrode approximately 10 mm wide in the longitudinal direction of the developing roller, and then connect a metal sheet wrapped tightly around the thin metal film electrode in a direction crossing the longitudinal direction to the measuring electrode protruding from the measuring device for measurement. In the case of a cylindrical developing roller, it is preferable to use a metal sheet wrapped tightly around the circumferential direction of the developing roller. This allows impedance measurement to be performed without being affected by fluctuations in the size of the outer edge (outer diameter for cylindrical developing rollers) in the cross section perpendicular to the longitudinal direction of the developing roller or by the surface shape. Aluminum foil, metal tape, etc. can be used as the metal sheet.

[0125] (Conditions for measuring the impedance of the developing roller) 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 will suffice. Among these, it is preferable to measure the impedance using an impedance analyzer, since this is in the range of the electrical resistance of the developing roller. 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 Hz frequency range. The measurement environment is a temperature of 23°C and a relative humidity of 50%. The impedance is measured at the center of the developing roller in the longitudinal direction. The voltage application condition is a DC voltage of 50V superimposed on an AC voltage of 50V.

[0126] More specifically, it is as follows. First, as a pretreatment, a measurement electrode is made by vacuum vapor deposition of platinum onto the developing roller while it is rotating. For the vapor deposition, a vacuum vapor deposition device with a mechanism for gripping the base part of the roller, which is the object to be deposited, and rotating it in the circumferential direction is used, and the roller rotation speed, vapor deposition distance, and vapor deposition time are controlled to vapor deposit a film thickness of 100 nm or more. Masking tape is used at this time. By forming the electrode with a film thickness of 100 nm or more, the contribution of the contact area between the measurement electrode and the developing roller due to the surface roughness of the developing roller can be minimized.

[0127] Next, an aluminum sheet is wrapped tightly around the electrode, and the aluminum sheet is connected to the measurement electrodes of an impedance measuring device (product names: Solartron 1260 and Solartron 1296, manufactured by Solartron) and a high-voltage system (product names: 6792 and HVA-500, manufactured by Toyo Corporation).

[0128] Figure 6 shows a schematic diagram of the state in which the measurement electrodes are formed on the developing roller. In Figure 6, 51 is a conductive substrate, 52 is a conductive 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 conductive layer 52.

[0129] Figure 7 shows a cross-sectional view of the developing roller with the measurement electrode formed on it. 61 is the conductive substrate, 62 is the elastic layer, 63 is the conductive layer, 64 is the insulating part, 65 is the platinum vapor deposition layer, and 66 is the aluminum sheet. As shown in Figure 7, it is important to sandwich the conductive layer between the conductive substrate and the measurement electrode.

[0130] 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 8 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.

[0131] 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 is obtained in Hz, and the frequency is 1.0 x 10 0 ~1.0×10 1 Check the minimum impedance value in Hz. The impedance measurement point is the center of the developing roller in the longitudinal direction.

[0132] [Surface potential of developing roller] In an environment with a temperature of 23°C and a relative humidity of 50%, 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 developing roller was 1.0 mm and the width direction of the grid was aligned with the axial direction of the developing roller. A voltage of 8 kV was applied to the grid, and the corona discharger was moved relative to the developing roller in the axial direction at a speed of 400 mm / s to charge the outer surface of the developing roller. The corona discharger was stopped at a measurement position on the developing roller, and the change in the surface potential of the developing roller was measured at 0.01 second intervals from 0.06 seconds to 100.00 seconds after passing the grid.

[0133] When the time from passing through the grid is t (seconds), the surface potential at t = 0.06 is V INI Furthermore, the measurement results for 30.00≦t≦100.00 are fitted to the following formula (X') by the least squares method, and V 0,1 , and τ1 are calculated. V1(t)=V 0,1 exp(-t / τ1) (X') Furthermore, from V1, which is the value when t = 0.06 [seconds] is substituted into the above formula, V INI Calculate -V1.

[0134] In addition, the measurement results for 0.06≦t≦100.00 were fitted to the following equation (Y) using the least squares method, and V 0,2 and τ2 are calculated. V(t)=V1(t)+V2(t) (Y) In formula (Y), V2(t)=V 0,2 exp(-t / τ2) (Z) The above measurement is carried out at 9 points in total, 3 points in the longitudinal direction and 3 points in the circumferential direction of the developing roller, and the arithmetic mean value is taken as the V of the developing roller. INI Let V1, τ1, and τ2 be -V1, τ1, and τ2.

[0135] The surface potential of the developing roller can be measured, for example, using the device shown in Figure 9. Both ends of substrate 82 of developing roller 81 are held by chucks 83, and a measuring unit 86, which includes a corona discharger 84 and a surface electrometer 85 arranged in parallel with a 25 mm gap between them, is positioned facing the surface of developing roller 81 at a distance of 1.0 mm. With developing roller 81 stationary, a voltage of 8 kV is applied to the grid portion of corona discharger 84, and measuring unit 86 is moved in the axial direction of developing roller 81 at a speed of 400 mm / sec. The change in the surface potential of the developing roller from 0.06 seconds to 100.00 seconds after passing through corona discharger 84 is measured using surface electrometer 85 at 0.01 second intervals. The meaning of the measurement conditions and measurement values ​​has been explained above in (Technical significance of requirement (2)), so it will not be covered here.

[0136] More specifically, it is as follows. The surface potential of the developing roller is measured using a charge measurement device (product name: DRA-2000L, manufactured by QEA). Specifically, in an environment of 23°C temperature and 50% relative humidity, a corona discharger with a grid is placed so that the distance between the grid and the outer surface of the developing roller is 1.0 mm and the width direction of the grid coincides with the axial direction of the developing roller. The grid of the corona discharger of the above device is 3.0 mm wide. Next, a voltage of 8 kV is applied to the corona charger, and the corona charger is moved relatively along the axial direction of the developing roller at a speed of 400 mm / s to charge the surface of the conductive member. The change in the surface potential of the developing roller is measured at 0.01 second intervals from 0.06 seconds to 100.00 seconds after passing the grid section.

[0137] [Calculation of various physical properties such as the circle equivalent 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 are measured by the following method. First, a section (0.5 to 1.0 mm thick) is cut using a razor so that a cross section perpendicular to the longitudinal direction of the developing roller can be observed. If the adhesion between the substrate and the resin layer is high and cutting with a razor is difficult, the entire 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.

[0138] 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, in order to quantify the cross-sectional images obtained by SEM observation, the cross-sectional images were processed using image processing software (trade name: Luzex AP, manufactured by Nireco Corporation) to obtain 8-bit resolution. The cross-sectional image is then grayscaled to obtain a monochrome image with 256 gradations. Next, the image is inverted so that the carbon black in the cross-sectional image appears white, and a binarization threshold is set for the brightness distribution of the image based on the algorithm of Otsu's discriminant analysis method, resulting in a binarized image in which the carbon black appears white and the binder resin appears black.

[0139] 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. Then, the arithmetic mean value and standard deviation of the obtained distribution of the circle equivalent diameter and the distance between adjacent walls were calculated. Although there is no particular problem with the number of images used for image analysis, at least three images should be used to eliminate the influence of differences in the longitudinal direction of the carbon black dispersed in the resin layer of the developing roller.

[0140] The number-average diameter of the primary particles of the carbon black dispersed in the resin is measured using a transmission electron microscope (TEM). First, a thin sectioned sample is prepared. A known method can be used for thinning. For example, the sample can be thinned using an ion beam or a diamond knife. In this disclosure, a 40 nm thick thin sectioned sample for observation is prepared using an ultramicrotome (product name: ULTRACUT-S, manufactured by Leica Microsystems). Then, a TEM image is obtained using a transmission electron microscope (product name: H-7100FA, manufactured by Hitachi High-Technologies Corporation) under measurement conditions of TE mode and an accelerating voltage of 100 kV. Then, using image analysis software (trade name: WinROOF, manufactured by Mitani Shoji Co., Ltd.) for the obtained TEM image, the circle-equivalent diameters of 50 primary particles of carbon black in the TEM image are measured, and the number-average value of the 50 particles is taken as the number-average diameter of the primary particles.

[0141] [Confirmation of the first and second areas] The outer surface of the developing roller was observed using a laser microscope (product name: VK-X100, manufactured by Keyence Corporation) with a 20x objective lens attached. On the roller surface, island-like repelled first regions and second regions where the conductive layer was exposed on the surface could be confirmed.

[0142] [Percentage of total area of ​​first area] An objective lens with a magnification of 20x was installed on a laser microscope (product name: VK-X100, manufactured by Keyence Corporation). Images of the surface of the developing roller were taken at nine areas: two locations 10 mm inward from both ends in the longitudinal direction, one location in the center, and three locations in the circumferential direction (at 120° intervals). Next, the tilt of the obtained observation image is corrected in quadric surface correction mode, assuming that the axial direction of the developing roller and the observation image are now parallel. At the center of the corrected image, the total area occupied by the first region within a square area with sides of 300 μm is measured. The total area occupied by this first region is divided by the square area with sides of 300 μm, and the resulting value is used as the percentage of the total area of ​​the first region. The arithmetic mean of the total area percentages obtained for the nine regions is calculated, and this is used as the percentage of the total area of ​​the first region of the developing roller.

[0143] [Resistance measurement of the first region] A sample including the first region is cut out from the developing roller, and a thin sample having a planar size of 50 μm square and a thickness t of 100 nm is prepared using a microtome. Next, this thin sample is placed on a metal flat plate, and a pressing surface area S of 100 μm is pressed from above. 2 The thin sample is pressed against the metal terminal. In this state, a voltage of 1 V is applied between the metal terminal and the metal plate using an electrometer 6517B (trade name, manufactured by KEITHLEY) to measure the resistance R. From this resistance R, the volume resistivity pv (Ω·cm) is calculated using the following formula. pv=R×S / t

[0144] (Measurement of DBP absorption amount of carbon black) The DBP absorption of carbon black is measured for carbon black powder in accordance with Japanese Industrial Standards (JIS) K6217-4.

[0145] (Measurement of pH of carbon black) The pH of carbon black is measured on carbon black powder according to ASTM D1512.

[0146] <Toner> The toner according to the present disclosure comprises toner particles and fine particles having a compound containing a metal element. The metal element is at least one element selected from the group consisting of titanium, aluminum, zirconium, and zinc. When the toner surface is measured by X-ray photoelectron spectroscopy, the abundance ratio of the metal element is 2.0 to 20.0 atomic %. The average circularity of the toner is 0.970 or more.

[0147] [Toner particles] The toner particles according to one embodiment of the present disclosure contain a binder resin. The toner particles may also contain a colorant and other components. The binder resin may be a resin that is generally used as a binder resin for toner. Specifically, styrene-acrylic resins (styrene-acrylic acid ester copolymers, styrene-methacrylic acid ester copolymers, etc.), polyester resins, epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, styrene-butadiene copolymers, mixed resins or composite resins thereof, etc. The resin is preferably an amorphous resin. The colorant is not particularly limited, and any known colorant can be used.

[0148] The toner particles may contain a release agent. The release agent is not particularly limited, and the following known release agents can be used: petroleum waxes and derivatives thereof, such as paraffin wax, microcrystalline wax, and petrolatum; montan wax and derivatives thereof; hydrocarbon waxes and derivatives thereof produced by the Fischer-Tropsch process; polyolefin waxes and derivatives thereof, such as polyethylene and polypropylene; natural waxes and derivatives thereof, such as carnauba wax and candelilla wax; higher aliphatic alcohols; fatty acids, such as stearic acid and palmitic acid, or compounds thereof; acid amide waxes; ester waxes; ketones; hydrogenated castor oil and derivatives thereof; vegetable waxes; animal waxes; and silicone resins. Derivatives include oxides, block copolymers with vinyl monomers, and graft-modified products. These can be used alone or in combination.

[0149] The toner particles may contain a crystalline resin. The crystalline resin is not particularly limited, and known resins may be used. Specific examples include crystalline polyester resins and crystalline acrylic resins. The crystalline resin may be a block polymer having a crystalline portion and an amorphous portion. The toner particles may contain a charge control agent, and known charge control agents can be used.

[0150] An example of a method for producing toner particles will be given below. (1) Suspension polymerization method: A polymerizable monomer composition containing a polymerizable monomer capable of producing a binder resin, and optionally a release agent, a colorant, etc., is granulated in an aqueous medium, and the polymerizable monomer is polymerized to obtain toner particles. (2) Pulverization method: A binder resin, and optionally a release agent and a colorant, are melted and kneaded, and then pulverized to obtain toner particles. (3) Dissolution suspension method: Toner particles are obtained by dissolving a binder resin, and optionally a release agent and a colorant, in an organic solvent to produce an organic phase dispersion, followed by suspending the dispersion in an aqueous medium, granulating the dispersion, and polymerizing the dispersion, followed by removing the organic solvent. Alternatively, the toner particles obtained by the pulverization method may be thermally spheronized to adjust the average circularity. (4) Emulsion aggregation polymerization method: Binder resin particles, and optionally particles of a release agent and a colorant, are aggregated and associated in an aqueous medium to obtain toner particles. Examples of aqueous media include the following: water; mixed solvents of water and alcohols such as methanol, ethanol, and propanol;

[0151] Among these, the suspension polymerization method is preferred, since the toner particles produced by the suspension polymerization method have an almost uniform spherical shape, which makes it easy to increase the average circularity and facilitates the toner to roll on the developing roller.

[0152] [Fine particles] The fine particles have a compound containing a metal element, and the metal element is at least one selected from the group consisting of titanium, aluminum, zirconium, and zinc. Examples of such compounds containing a metal element include at least one selected from the group consisting of titanium-based compounds, aluminum-based compounds, zirconium-based compounds, and zinc-based compounds. Specific examples include metal oxides such as titanium oxide, aluminum oxide, and zinc oxide, composite oxides such as strontium titanate and barium titanate, and polyvalent metal salts such as titanium phosphate, zirconium phosphate, and aluminum phosphate. The compound containing a metal element is preferably at least one selected from the group consisting of titanium oxide, aluminum oxide, zinc oxide, strontium titanate, zirconium phosphate, and titanium phosphate. Whether the compound containing a metal element is a metal oxide, a composite oxide, or a polyvalent acid metal salt can be confirmed by observing the toner surface using STEM-EDS, which will be described later. The fine particles are preferably particles of a compound containing a metal element.

[0153] In addition, when the surface of the toner according to the present disclosure is measured by X-ray photoelectron spectroscopy, the abundance ratio of the metal element is 2.0 to 20.0 atomic %. A compound containing at least one element selected from the group consisting of titanium, aluminum, zirconium, and zinc as a metal element has low electrical resistance, and the abundance ratio of the metal element measured by X-ray photoelectron spectroscopy indicates the amount of the compound containing the metal element present on the toner surface. By having a compound containing a metal element present on the toner surface so that the metal element is present in an amount of 2.0 atomic % or more, the electrical resistance of the toner surface can be reduced, allowing charge transfer between toner particles to occur. Furthermore, by having a compound containing a metal element present on the toner surface so that the metal element is present in an amount of 20.0 atomic % or less, the toner can maintain its charge retention properties and prevent poor transfer performance due to excessive charge reduction. The metal element content is more preferably 5.0 atomic % or more. The metal element content may be 5.0 to 20.0 atomic %, or 5.0 to 10.0 atomic %. When there are multiple types of metal elements, the abundance ratio of the metal elements is the total abundance ratio of all the metal elements.

[0154] Examples of methods for adjusting the content of the metal element within the above range include a method in which the fine particles are mixed with the toner particles in a mixer and then externally added, and a method in which the metal element is precipitated in particulate form on the surface of the toner particles. The mixer for externally adding fine particles to toner particles is not particularly limited, and any known mixer, whether dry or wet, can be used. Examples include FM Mixer (manufactured by Nippon Coke & Engineering Co., Ltd.), Super Mixer (manufactured by Kawata Corporation), Nobilta (manufactured by Hosokawa Micron Corporation), and Hybridizer (manufactured by Nara Kikai Co., Ltd.). To control the coating state of the fine particles, the toner can be prepared by adjusting the rotation speed, processing time, and water temperature and amount in the jacket of the external addition device.

[0155] The content of the fine particles for adjusting the abundance ratio of the metal element to the above range by these methods is preferably 2.0 parts by mass or more and 10.0 parts by mass or less, and more preferably 3.0 parts by mass or more and 10.0 parts by mass or less, relative to 100 parts by mass of the toner particles.

[0156] Furthermore, the conductivity of the particles determined by impedance measurement is 1.0 × 10 -9 ~1.0×10 2 The conductivity of the particles is preferably 1.0×10 -9By setting the surface resistivity of the toner particles to 1.0×10 or more and the proportion of the metal element to be present within the above range, the electrical resistance in the surface direction of the toner particles is likely to decrease, and charge transfer between the toner particles is more likely to occur. 2 By setting the conductivity of the fine particles to 1.0×10 S / m or less, it is easy to suppress excessive reduction in the toner charge. -8 ~1.0×10 -1 S / m, and more preferably 1.0×10 -8 ~1.0×10 -3 S / m. The conductivity of the fine particles can be changed by changing the type of compound containing the metal element. The method for measuring the conductivity of the fine particles will be described later.

[0157] When an EDS mapping image of the constituent elements of the cross section of the toner is obtained by analyzing the cross section of the toner observed with a scanning transmission electron microscope using an energy dispersive X-ray spectrometer, The number average length of the fine particles having a signal derived from a metal element in the normal direction to the outline of the toner particle at the contact point between the fine particles having a signal derived from a metal element and the toner particle is preferably 0.01 to 0.50 μm. This indicates the number-average particle size of the particles. When the number-average length of the particles is 0.01 μm or more, charge transfer occurs easily when toner particles come into contact with each other. Also, when the number-average length of the particles is 0.50 μm or less, This makes it easy to reduce the resistance in the surface direction of the toner when the abundance ratio of the metal element is within the above range. The number average length of the fine particles is more preferably 0.30 μm or less, and even more preferably 0.20 μm. The number average length of the fine particles may be 0.01 to 0.30 μm, or may be 0.01 to 0.20 μm. The number average length of the fine particles can be adjusted by changing the number average particle size of the primary particles of the fine particles. The method for measuring the number average length of the fine particles will be described later.

[0158] In addition to the fine particles, the toner may contain conventionally known external additives without any particular restrictions. Specifically, the following can be mentioned: Raw silica fine particles such as wet process silica and dry process silica, or surface-treated silica fine particles obtained by surface-treating such raw silica fine particles with a treating agent such as a silane coupling agent, a titanium coupling agent, or silicone oil; resin fine particles such as vinylidene fluoride fine particles and polytetrafluoroethylene fine particles, etc. The content of the external additive is not particularly limited, and may be 0.01 to 2.00 parts by mass with respect to 100 parts by mass of the toner particles.

[0159] The average circularity of the toner is 0.970 or more. When the average circularity of the toner is 0.970 or more, the toner becomes spherical enough to roll, and the toner easily rolls when a shear force is applied to the toner. The average circularity of the toner is preferably 0.970 to 1.000, more preferably 0.980 to 1.000. Alternatively, it may be 0.970 to 0.990, or 0.980 to 0.990. The average circularity of the toner can be adjusted by the method for producing the toner particles. In order to adjust the average circularity to the above range, it is preferable to select a suspension polymerization method. When other production methods are selected, the average circularity can be adjusted to the above range by adding a spheronization step. The method for measuring the average circularity of the toner will be described later.

[0160] The volume average particle diameter of the toner is preferably 6.4 to 7.0 μm, and more preferably 6.6 to 7.0 μm. When the volume average particle diameter of the toner is in the above range, the developing roller It is easy to spontaneously replace them. The method for measuring the volume average particle size of the toner will be described later.

[0161] [Method for confirming the presence of fine particles and their number-average particle size] (Observation of toner surface using STEM-EDS) Using a scanning transmission electron microscope (STEM), a slice containing the outermost surface of the toner is observed by the following method. First, the toner is thoroughly dispersed in a room-temperature curing epoxy resin, and then cured for two days in a 40°C atmosphere. A 50-nm-thick thin sample containing the toner's outermost surface is cut from the cured product using a microtome (EM UC7: manufactured by Leica) equipped with a diamond blade. This sample is then magnified 100,000 times using a STEM (JEM2800: manufactured by JEOL Ltd.) with an accelerating voltage of 200 V and an electron beam probe size of 1 mm, to observe the outermost surface of the toner.

[0162] Next, the constituent elements of the outermost surface of the obtained toner are analyzed using energy dispersive X-ray spectroscopy (EDS), and an EDS mapping image (256 x 256 pixels (2.2 nm / pixel), 200 accumulations) is created. When a signal derived from a metal element is observed on the surface of the toner in the prepared EDS mapping image and particles are observed at the same position in the STEM image, the particles are considered to be the fine particles according to the present disclosure. Furthermore, the elements detected at the same position as the signal derived from the metal element confirm that the fine particles are metal oxides, composite oxides, polyvalent acid metal salts, etc. Furthermore, in the region outside the contour of the toner particle, the length of the fine particles having a signal derived from the metal element is measured in the normal direction to the contour of the toner particle at the point of contact between the fine particles having a signal derived from the metal element and the toner particle. The lengths of 30 fine particles are measured using the above method, and the arithmetic average value is taken as the number-average length of the fine particles. Note that the normal to the contour of the toner particle is determined by the point of contact between the fine particles having a signal derived from the metal element and the toner particle that is located furthest toward the center of the toner particle.

[0163] [Method for measuring the proportion of metal elements on the toner surface] (Calculation of the abundance ratio of metal elements using X-ray photoelectron spectroscopy) The content ratio of the metal element is calculated by measuring the toner under the following conditions. Measurement equipment: X-ray photoelectron spectrometer: Quantum2000 (ULVAC-PHI, Inc.) X-ray source: Monochrome Al Kα ·Xray Setting:100μmφ(25W(15KV)) Photoelectron take-off angle: 45 degrees Neutralization Condition: Neutralization Gun and Ion Gun Used Together ·Analysis area: 300μm×200μm Pass Energy: 58.70 eV Step size: 0.125eV Analysis software: Maltipak (PHI)

[0164] Next, a method for determining the quantitative value of a metal element by analysis will be described below, taking the case where Ti element is used as the metal element as an example. First, the peak derived from the C-C bond of the carbon 1s orbital is corrected to 285 eV. Then, from the peak area derived from the Ti 2p orbital, which has its peak top detected at 452 to 468 eV, the amount of Ti derived from the Ti element relative to the total amount of constituent elements is calculated using the relative sensitivity factor provided by ULVAC-PHI, and this value is taken as the abundance ratio (atomic %) of the Ti element on the toner surface. In the case of Al element, the peak top is detected around 73 eV, which is derived from the Al 2p orbital. The peak area is used. In the case of Zr element, the peak area derived from the Zr 3d orbital, whose peak top is detected at 170 to 190 eV, is used. In the case of Zn element, the peak area derived from the Zn 2p orbital, whose peak top is detected at 1020 to 1050 eV, is used.

[0165] [Method for measuring average circularity of toner] The average circularity of the toner is measured using a flow particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) under the measurement and analysis conditions used during the calibration process. The specific measurement method is as follows. First, 20 mL of ion-exchanged water, from which impurities such as solids have been removed, is placed in a glass container. 0.2 mL of a solution prepared by diluting "Contaminon N" (a 10% by weight aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) three times by weight with ion-exchanged water is added. 0.02 g of the sample to be measured is then added, and the mixture is dispersed for 2 minutes using an ultrasonic disperser to obtain the dispersion for measurement. The dispersion is then cooled appropriately to a temperature between 10°C and 40°C. A tabletop ultrasonic cleaner disperser with an oscillation frequency of 50 kHz and an electrical output of 150 W (e.g., "VS-150" manufactured by Vervoclear) is used as the ultrasonic disperser. A predetermined amount of ion-exchanged water is placed in the water tank, and 2 mL of the Contaminon N is added to the water tank. For the measurement, a flow-type particle image analyzer equipped with a "LUCPLFLN" objective lens (magnification 20x, numerical aperture 0.40) is used, and a particle sheath "PSE-900A" (manufactured by Sysmex Corporation) is used as the sheath liquid. The dispersion liquid prepared according to the above procedure is introduced into the flow-type particle image analyzer, and 2,000 toner particles are counted in HPF measurement mode and total count mode. Then, the binarization threshold for particle analysis is set to 85%, the particle diameters to be analyzed are limited to equivalent circle diameters of 1.977 μm or more and less than 39.54 μm, and the average circularity of the toner particles is determined. Before starting the measurement, automatic focus adjustment is performed using standard latex particles (for example, Duke Scientific's "RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5100A" diluted with ion-exchanged water). After that, focus adjustment is performed every two hours from the start of the measurement. In the examples, a flow particle image analyzer was used that had been calibrated by Sysmex Corporation and had a calibration certificate issued by Sysmex Corporation. Measurements were performed under the same measurement and analysis conditions as when the calibration certificate was issued, except that the particle diameter to be analyzed was limited to a circle-equivalent diameter of 1.977 μm or more and less than 39.54 μm.

[0166] [Method for measuring the volume average particle size of toner] The volume average particle size of the toner or toner particles (hereinafter also referred to as toner, etc.) is calculated as follows. The volume average particle diameter (Dv) of the toner is calculated as follows. The measurement device used is a particle counting analyzer "CDA-1000X" (manufactured by Sysmex Corporation) equipped with a 100 μm aperture tube and employing the pore electrical resistance method. The measurement conditions are set and the measurement data is analyzed using the accompanying dedicated software "CDA-1000X" (manufactured by Sysmex Corporation). The aqueous electrolyte solution used for the measurement may be, for example, "Cell Pack" (manufactured by Sysmex Corporation). Before performing measurements and analysis, the dedicated software is set up as follows.

[0167] On the "measurement condition setting" screen of the dedicated software, set the total count number to 50,000, the number of repeated measurements to 1, and the measurement mode to total count (no limit). The specific measurement method is as follows. (1) Pour 150 ml of the electrolyte solution into a dedicated glass round-bottom beaker, set it on the sample stage, and stir with the stirring propeller at 500 rpm. Then, click "Blank Check Measurement" in the dedicated software to start the measurement and confirm that the count is less than 500. If the count is 500 or more, repeatedly clean the beaker and aperture. (2) 30 ml of the above-mentioned electrolyte solution is placed in a 100 ml flat-bottom glass beaker, and 0.3 ml of a dilution of "Contaminon N" (a 10% by weight aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) diluted approximately three times by weight with ion-exchanged water is added as a dispersant. (3) Prepare an ultrasonic disperser "Ultrasonic Dispension System Tetra150" (manufactured by Nikkaki Bios Co., Ltd.) with an electrical output of 120 W and two built-in oscillators with an oscillation frequency of 50 kHz and a phase shift of 180 degrees. Place 3.3 L of ion-exchanged water in the ultrasonic disperser's water tank and add 2 mL of Contaminon N to this water tank. (4) Set the beaker (2) in the beaker fixing hole of the ultrasonic disperser, operate the ultrasonic disperser, and adjust the height of the beaker so that the resonance state of the liquid surface of the electrolytic solution in the beaker is maximized. (5) While ultrasonic waves are irradiated into the electrolyte solution in the beaker from (4), 10 mg of toner is added little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. During the ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted so that it is between 10°C and 40°C. (6) Using a pipette, add the electrolyte solution (5) containing the dispersed toner to the round-bottom beaker (1) placed in the sample stand, and adjust the measurement concentration to approximately 6%. Then, measure the particle count until it reaches 50,000 particles. (7) The measurement data is analyzed using the dedicated software provided with the device to calculate the volume average particle size (Dv).

[0168] [Method for measuring impedance of fine particles and calculation of conductivity] The capacitance and conductivity of air and powder are measured by impedance measurement using the parallel plate capacitor method. The equipment used is a toner measurement jig consisting of a four-terminal sample holder SH2-Z (manufactured by Toyo Corporation) and a torque wrench adapter SH-TRQ-AD (optional), and a material testing system ModuLab XM MTS (manufactured by Solartron Corporation). In addition, a noise-cutting transformer NCT-I3 1.4kVA (manufactured by Denken Seiki Kenkyusho Co., Ltd.) is used to suppress commercial power supply noise, and a shielding box is used to suppress electromagnetic noise.

[0169] The measurement jig uses a four-terminal sample holder and the optional torque wrench adapter SH-TRQ-AD, and uses the upper electrode (Φ25mm solid electrode) SH-H25AU and the lower electrode for liquids / powder (center electrode Φ10mm; guard electrode Φ26mm) SH-2610AU as parallel plate electrodes, and is configured to be able to measure resistances of 0.1Ω to 1TΩ for electrical signals of up to 500Vp-p and DC to 1MHz.

[0170] In addition, to adjust the pressure on the sample, a torque wrench adapter SH-TRQ-AD (manufactured by Toyo Corporation) was attached to the micrometer used to measure the film thickness between the upper and lower electrodes on the four-terminal sample holder. For the torque driver used for pressure control, if the powder to be measured is fine particles, a torque driver RTD30CN (manufactured by Tohnichi Manufacturing Co., Ltd.) with a 6.35 mm square bit is used, configured so that the tightening torque can be controlled to 20.0 cN·m.

[0171] The electrical AC characteristics were measured using the ModuLab XM MTS (Solar Test System) Impedance measurements are performed using a meter (manufactured by Ron Co., Ltd.). The ModuLab XM MTS consists of the control module XM MAT 1MHz, the high-voltage module XM MHV100, the femtocurrent module XM MFA, and the frequency response analysis module XM MRA 1MHz, and the control software is the company's own XM-studio MTS Ver.3.4.

[0172] The particle measurement conditions are Normal Mode, which only performs measurement, with an AC level of 0.5 Vrms, a DC bias of 0 V, and a sweep frequency of 1 MHz to 0.01 Hz (12 points / decade or 6 points / decade). Furthermore, in consideration of noise suppression and shortening of measurement time, the following settings are added for each sweep frequency. Sweep frequency 1MHz~10Hz Measurement integration time 64 cycles Sweep frequency 10Hz to 1Hz Measurement integration time 24 cycles Sweep frequency 1Hz to 0.01Hz Measurement integration time 1 cycle Under the above measurement conditions, the impedance characteristics, which are the electrical AC characteristics of the particles, are measured.

[0173] By performing measurements under the above conditions, a powder measurement jig based on the parallel plate capacitor method is used, and the impedance characteristics of the air and sample at the film thickness d according to the pressure torque and the measurement electrode S of 10 mm in diameter can be obtained.

[0174] From the obtained impedance characteristics of the air and sample, data correction processing for the measurement system is performed to obtain highly reliable capacitance C and conductance (conductivity) G. From the obtained capacitance C, conductance (conductivity) G, and the geometric shape of the measurement jig (parallel plate electrode size S and sample film thickness), the electrical properties of relative permittivity and conductivity are calculated.

[0175] When using the 4-terminal sample holder SH2-Z for the first time, two verifications must be carried out to find the optimal measurement conditions, since there are individual differences in the 4-terminal sample holder SH2-Z used in powder measurement jigs.

[0176] The first verification is the film thickness dependency characteristics of the four-terminal sample holder. The dependency on air thickness (distance between the upper and lower electrodes) is measured, the error between the theoretical value of capacitance and the measured value is confirmed, and the optimal range or film thickness at which the measurement error is minimized is identified.

[0177] The second verification is the measurement of mechanical error. When measuring powder samples, a torque-controlled load is applied to maintain a constant volume density. In contrast, when measuring air, no load is applied. At this time, film thickness errors occur due to the influence of dimensions such as mechanical processing accuracy. Therefore, the offset value when the tightening torque control value (6.5 cN m in this jig) is loaded and unloaded is confirmed, and this is used as the offset correction value.

[0178] The specific sample preparation and measurement procedures are as follows. (1) Pile powder on the center electrode of the lower electrode and shape it into a trapezoidal shape with a height of 5 mm. (2) The lower electrode with the powder piled on it is attached to the four-terminal sample holder SH2-Z, and the upper electrode is lowered. (3) At this time, the upper electrode is lowered to the top end of the powder while keeping it constant so as not to rotate unintentionally. (4) While rotating the upper electrode left and right, smoothing treatment is performed to make the powder smooth. (5) Using a micrometer, adjust the film thickness to a predetermined value while maintaining the rotation direction of the upper electrode in a uniform, constant direction. (6) Apply pressure using a torque driver. (7) Measure the sample film thickness using a micrometer. (8) Impedance measurement is carried out under the above conditions. (9) After the measurement is completed, raise the upper electrode and remove the lower electrode. At this time, remove the lower electrode carefully so that powder does not get into the contact terminal for the lower electrode of the four-terminal sample holder, and protect it with masking tape. (10) Clean the upper and lower electrodes. (11) Remove the masking tape and attach the lower electrode. (12) The sample film thickness d obtained in step (7) is adjusted to the air thickness t, taking into account offset correction in the no-load state, and the rotation direction of the upper electrode is kept constant. (13) Conduct air impedance measurements. (14) If the measurement data (dielectric tangent; tanδ) of the air measured in step (13) is 0.002 or more in the frequency range of 100 Hz to 0.01 Hz, the cleaning is insufficient, so the work is to be started again from the cleaning step (10). The measurement is carried out at 25°C.

[0179] The specific data processing procedure is as follows. (15) From the measured impedance characteristics of air, the error of the phase characteristics relative to the theoretical value is calculated, and phase correction data for the material testing system ModuLab XM MTS (manufactured by Solartron) is obtained. (16) The phase correction data calculated in step (15) is applied to the impedance characteristics of the air measured in step (13) to obtain the phase-corrected impedance characteristics of the air. (17) The capacitance Ca is calculated from the admittance Ya=Ga+jωCa of the phase-corrected impedance characteristic of air, and the error from the theoretical value is calculated to obtain correction data α for the film thickness error. (18) The phase correction process obtained in step (15) is applied to the impedance characteristics of the powder sample measured in step (8). (19) By calculating the complex admittance Ym = Gm + jωCm of the characteristics that have been subjected to the phase correction processing in step (18) using the capacitance Ca of the air obtained in step (17) and its correction data α, highly reliable relative permittivity and conductivity of the powder sample can be obtained. The conductivity of the microparticles in this disclosure is the value of the conductivity at a frequency of 0.01 Hz.

[0180] [Method for measuring work function] The work function of the conductive portion, insulating portion, fine particles, and external additives of the developing roller is measured by the following measurement method. The work function is expressed numerically as the energy (eV) required to extract an electron from the substance. The work function is measured using a surface analyzer (AC-2 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 light intensity: 800nW Spectrometer: Monochromatic light Spot size: 4mm x 4mm Energy scan range: 3.6 to 6.2 eV Anode voltage: 2910V Measurement time: 30 [sec / 1 point] The photoelectrons emitted from the sample surface are detected and processed using work function calculation software built into the surface analyzer. The work function is measured with a repeatability (standard deviation) of 0.02 eV. When measuring powder, a powder measurement cell is used. 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]. The energy threshold is the work function [eV].

[0181] In the work function measurement curve obtained by measurement under the above conditions, the horizontal axis represents excitation energy [eV], and the vertical axis represents the 0.5th power of the number of emitted photoelectrons (normalized photon yield). Generally, when the excitation energy value exceeds a certain threshold, the emission of photoelectrons, i.e., the normalized photon yield, increases rapidly, and the work function measurement curve rises sharply. The excitation energy at which this rise occurs is defined as the photoelectric work function value Wf [eV]. This photoelectric work function value Wf [eV] is taken to be the work function of the sample.

[0182] The work functions of the conductive and insulating parts of the developing roller are measured by applying the conductive layer-forming coating liquid and the insulating part-forming coating liquid to an aluminum sheet, drying and curing the coating liquid under the conditions described in the manufacturing examples below.

[0183] The work function of the conductive portion of the developing roller is not particularly limited and may be 4.0 to 5.0. The work function of the insulating portion of the developing roller is not particularly limited and may be 4.0 to 5.0. The work function of the fine particles is not particularly limited and may be 4.0 to 6.0. The work function of the external additive is not particularly limited and may be 4.0 to 6.0.

[0184] <Process cartridge and electrophotographic image forming apparatus> The developing roller according to the present disclosure can be suitably used as a developing roller in a process cartridge. FIG. 4 is a schematic cross-sectional view of an example of a process cartridge according to one embodiment of the present disclosure. The process cartridge 22 is configured to be detachably mountable to the main body of an electrophotographic image forming apparatus. The process cartridge 22 integrates a developing device 18 including a developing roller 14 and a developing blade 15, a photosensitive member 19, a charging roller 20, and a cleaning blade 21. That is, the process cartridge is equipped with a developing means, and the developing means has the developing device 18. The developing device 18 is further filled with toner 16. The toner 16 is supplied to the surface of the developing roller 14 by a toner supply roller 17, and a layer of toner 16 of a predetermined thickness is formed on the surface of the developing roller 14 by the developing blade 15.

[0185] The developing roller 14 is in contact with the photosensitive member 19 and is driven to rotate at a predetermined peripheral speed ratio relative to the photosensitive member 19. A predetermined bias is applied to the developing roller 14, and the electrostatic latent image on the photosensitive member 19 is developed with the toner 16 to be visualized.

[0186] The toner supply roller 17 contacts the developing roller 14, penetrates a predetermined amount, and rotates in the same direction as or opposite to the rotation direction of the developing roller 14. A predetermined bias may be applied to the toner supply roller 17. By reducing the difference in relative speed between the toner supply roller 17 and the developing roller 14 or by reducing the penetration amount of the toner supply roller 17 into the developing roller 14, the drive torque can be significantly reduced.

[0187] One end of the developing blade 15 is fixed to the developing device 18, and the other free end is arranged in contact with the developing roller 14 in the counter direction to the rotational direction. By arranging the developing blade 15 in contact with the developing roller 14, the amount of toner on the developing roller 14 is regulated, making the layer thinner and forming a toner layer of uniform thickness. In addition, a predetermined bias is applied to the developing blade 15, which imparts an electric charge to the toner 16 and the insulating portion on the outer surface of the developing roller 14.

[0188] FIG. 5 is a schematic cross-sectional view showing an example of an electrophotographic image forming apparatus equipped with a contact-type developing device using one-component toner. The developing device 18 includes a toner 16 as a one-component toner, a developing roller 14, a toner supply roller 17 that supplies the toner to the developing roller 14, and a toner layer on the developing roller 14 that defines the thickness of the toner layer. and a developing blade 15 that controls the development. That is, the electrophotographic image forming apparatus is equipped with a developing means, and the developing means has a developing device 18. The developing roller 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. Note that 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 prepared with toners of black, cyan, magenta, and yellow, enabling color printing.

[0189] The printing operation of an electrophotographic image forming apparatus will now be described. Photoconductor 19 rotates in the direction of the arrow and is uniformly charged by charging roller 20, which charges photoconductor 19. Next, an electrostatic latent image is formed on the surface of photoconductor 19 by laser light 23, which serves as exposure means. The electrostatic latent image is visualized as a toner image (developed) by developing device 18, which applies toner 16 from developing roller 14, which is placed in contact with photoconductor 19. Development is what is known as reversal development, in which a toner image is formed in the exposed area.

[0190] The toner image formed on the photosensitive member 19 is transferred onto an intermediate transfer member 25 in the form of an endless belt by a transfer roller 24 which is a transfer member. Paper 26, which is a recording medium, is fed into the device by paper feed roller 27 and secondary transfer roller 28, and is transported together with intermediate transfer body 25 bearing a toner image to the nip between secondary transfer roller 28 and driven roller 29, where the toner image is transferred to paper 26. Intermediate transfer body 25 is operated by driven roller 29, drive roller 30, and tension roller 31. Toner remaining on intermediate transfer body 25 is cleaned by cleaning device 32.

[0191] A voltage is applied to the developing roller 14, developing blade 15, transfer roller 24, and secondary transfer roller 28 from a bias power supply 33. The paper 26 onto which the toner image has been transferred is fixed by a fixing device 34 and then ejected outside the device, completing the printing operation. Meanwhile, residual toner 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. [Example]

[0192] 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. Hereinafter, unless otherwise specified, "parts" refers to "parts by mass."

[0193] <1. Developing Roller Manufacturing Example> In this embodiment, a developing roller is described in which a conductive layer is laminated on an elastic roller having an elastic layer on the outer surface of a base body, and an insulating portion is further arranged, but the developing roller is not limited to this configuration.

[0194] <1-1. Preparation of raw materials for forming conductive layer and manufacturing example> [1-1-1. Preparation of raw polyol and manufacturing example] A synthesis example for obtaining a polyurethane resin layer will be shown below.

[0195] [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.

[0196] [Preparing raw polyol] Commercially available products were used as the five raw material polyols A-1 to A-5 shown in Table 1. Raw material polyols A-6 and A-7 were synthesized by the following method. [Table 1]

[0197] [Synthesis of raw material polyol A-6] Under a nitrogen atmosphere, 100.0 g of 1,3-propanediol, 49.4 g of adipic acid, and 69.5 g of ethylene carbonate were mixed and heated, and the temperature was raised to 200°C while the ethylene glycol and water produced in the reaction system were distilled off. After the ethylene glycol and water were distilled off, 15 ppm of titanium tetraisopropoxide was added, and the polycondensation reaction was further carried out under a reduced pressure of 266.7 Pa. The reaction solution was cooled to room temperature to obtain raw material polyol A-6. The number average molecular weight of the resulting raw material polyol A-6 was 2030.

[0198] [Synthesis of raw material polyol A-7] Raw material polyol A-7 was produced in the same manner as raw material polyol A-6, except that the starting materials shown in Table 2 below were used. The number average molecular weight of raw material polyol A-7 was 2,040. [Table 2]

[0199] [1-1-2. Preparation of raw material isocyanates B-1 to B-3] The raw material isocyanates shown in Table 3 below were prepared. [Table 3]

[0200] [1-1-3. Production 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 4 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, producing hydroxyl-terminated urethane prepolymer C-1. [Table 4]

[0201] [Synthesis of Hydroxyl-Terminated Urethane Prepolymers C-2 to C-5] Hydroxyl-terminated urethane prepolymers C-2 to C-5 were prepared using the starting materials listed in Table 5 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-5 are as follows: 1 H-NMR and 13 The molecular weights of the compounds were determined using C-NMR. In Table 5, m, n, q, r, and s in the structural formulae (1), (3), and (4) represent the average number of moles added. [Table 5]

[0202] Hydroxyl-terminated urethane prepolymer C-1 to C-2, which contains the structure represented by structural formula (1) in the molecule, For C2, R13 in structural formula (1) was the same as R12. In the tables, when "x, y = A", such as when m and n = 6.9, this indicates that the average number of moles of x and y added is A. The same applies to the following tables. Parts indicate parts by mass.

[0203] [1-1-4. Production of Isocyanate-Terminated Prepolymers D-1 to D-3] [Synthesis of isocyanate-terminated prepolymer D-1] The materials listed in Table 6 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. [Table 6]

[0204] [Synthesis of isocyanate-terminated prepolymers D-2 to D-3] Isocyanate group-terminated prepolymers D-2 and D-3 were prepared using the types and amounts of starting materials shown in Table 7 below in the same manner as in the synthesis of isocyanate group-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 weight was determined using C-NMR. In Table 7, m, n, o, p, and s in structural formulas (1), (2), and (4) represent the average number of moles added. Parts represent parts by mass. [Table 7]

[0205] 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.

[0206] <1-2. Preparation of conductive layer additives and manufacturing examples> [1-2-1. Preparation of Polyoxyethylene Polyoxypropylene Alkyl Ethers E-1 to E-2, Production Examples] [Preparation of polyoxyethylene polyoxypropylene alkyl ether] Additives E-1 and E-2 shown in Table 8 below, which are polyoxyethylene polyoxypropylene alkyl ethers, were commercially available products.

[0207] [1-2-2. Preparation of polyoxyethylene alkyl ether acetic acid, manufacturing example] [Preparation of polyoxyethylene alkyl ether acetic acid] E-3, which is a polyoxyethylene alkyl ether acetic acid as an additive, was synthesized as shown in Table 8 below.

[0208] [Synthesis of Polyoxyethylene Alkyl Ether Acetic Acid E-3] 55.0 g of polyoxyethylene methyl ether (trade name: BRAWNON MP-550, manufactured by Aoki Oil & Fat Chemicals Co., Ltd.; average number of moles of ethylene oxide added relative to alcohol: 12) was mixed with 510 ml of 1 mol / L aqueous sodium hydroxide solution, and 71.1 g of potassium permanganate was added and stirred at room temperature for 6 hours. Then, 760 ml of 2-propanol was added and stirred for 1 hour to quench the excess potassium permanganate. The by-product manganese oxide was filtered. The aqueous layer was extracted with dichloromethane and purified to obtain polyoxyethylene methyl ether acetic acid E-3. The structure of R71 and the value of x for E-3 are shown in Table 8.

[0209] [1-2-3. Preparation and production of polyetheramine] [Preparation of polyetheramine] Additive E-4, which is a polyetheramine shown in Table 8 below, was a commercially available product. [Table 8]

[0210] [1-2-4. Preparing the conductive agent] [Preparing carbon black] The conductive agents, carbon black M-1 and M-2, shown in Table 9 below, were commercially available products. [Table 9]

[0211] <1-3. Example of manufacturing a coating solution for forming a conductive layer> [1-3-1. Preparation of conductive layer forming coating solution F-1] The materials for conductive layer-forming coating solution F-1, the types and amounts of which are listed in Table 10 below, were added to a reaction vessel and stirred. Next, 2-butanone (MEK) was added so that the total solids ratio was 30 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, thereby producing conductive layer-forming coating solution F-1. [Table 10]

[0212] [1-3-2. Preparation of conductive layer forming coating solutions F-2 to F-13] Conductive layer-forming coating solutions F-2 to F-13 were prepared in the following manner. First, the hydroxyl-terminated urethane prepolymer, isocyanate-terminated prepolymer, additives, surface conditioner, carbon black, and roughening particles listed in Table 11 below were mixed in the same manner as in the preparation of resin layer-forming coating solution F-1. 2-Butanone (MEK) was then added to adjust the viscosity of the solution to within the range of 6 to 10 mPa·s, producing conductive layer-forming coating solutions F-2 to F-13. [Table 11]

[0213] [1-3-3. Preparation of conductive layer forming coating solution F-14] The materials listed in Table 12 below were added to a reaction vessel in the amounts indicated and stirred. Next, 2-butanone (MEK) was added to a total solids ratio of 30% by mass, and the mixture was mixed using a sand mill. Further 2-butanone (MEK) was added to adjust the viscosity of the liquid to within the range of 6 to 10 mPa·s, producing conductive layer-forming coating liquid F-14. [Table 12]

[0214] <1-4. Conductive Layer Roller Manufacturing Example> [1-4-1. Preparation of the substrate] As a substrate, a 6 mm diameter core bar made of stainless steel (SUS304) was prepared by applying a primer (product name: DY35-051, manufactured by Dow Toray Industries, Inc.) to the circumferential surface and baking it.

[0215] [1-4-2. Preparation of Elastic Layer] The substrate was placed in a mold, and an addition-type silicone rubber composition containing the materials shown in Table 13 was poured into the mold. It was poured into a cavity formed in a mold. [Table 13]

[0216] 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.

[0217] [1-4-3. Manufacture of conductive layer roller G-1] The elastic roller was oriented with its longitudinal direction in the vertical direction, and its upper end was gripped and immersed (dipped) in the conductive layer-forming coating solution F-1 to coat the surface of the elastic roller with the coating solution. The resulting coating was air-dried at room temperature for 30 minutes, and then dried and cured for 1 hour in a hot air circulating dryer set at 160°C. In this way, a conductive layer roller G-1 was obtained, in which a conductive layer with a thickness of 12 μm was formed on the elastic layer.

[0218] [1-4-4. Manufacture of Conductive Layer Rollers G-2 to G-14] Conductive layer rollers G-2 to G-14 were produced in the same manner as in the manufacturing example of conductive layer roller G-1, except that the conductive layer forming coating liquid F-1 was changed to F-2 to F-14 shown in Table 14 below. [Table 14]

[0219] <1-5. Preparation of materials for forming insulating parts and manufacturing examples> [1-5-1. Production of insulating part forming materials I-1 to I-5] [Preparing raw material monomers] The two raw material monomers H-1 and H-2 shown in Table 15 below were commercially available products. [Table 15]

[0220] [Synthesis of insulating material I-1] 42.5 g of 2,2-bis(4-hydroxyphenyl)propane (Tokyo Chemical Industry Co., Ltd., product code B0494), 37.5 g of 2,2-bis(3-methyl-4-hydroxyphenyl)propane (Tokyo Chemical Industry Co., Ltd., product code B1567), and 0.1 g of hydrosulfite were dissolved in 1100 ml of a 5% by mass aqueous sodium hydroxide solution. 500 ml of methylene chloride was added to the solution, and while stirring and maintaining the temperature at 15°C, 60 g of phosgene was then blown in over 60 minutes.

[0221] After the phosgene injection was completed, 1.3 g of pt-butylphenol (hereinafter abbreviated as "PTBP": manufactured by Tokyo Chemical Industry Co., Ltd., product code B0383) was added as a molecular weight modifier and stirred to emulsify the reaction solution. After emulsification, 0.4 ml of triethylamine was added, and the mixture was stirred at 23°C for 1 hour to allow polymerization.

[0222] After the polymerization was completed, the reaction solution was separated into an aqueous phase and an organic phase. The organic phase was neutralized with phosphoric acid and repeatedly washed with water until the conductivity of the washing liquid (aqueous phase) reached 10 μS / cm or less. The resulting polymer solution was added dropwise to warm water maintained at 45°C, and the solvent was evaporated to obtain a white powdery precipitate. The resulting precipitate was filtered and dried at 110°C for 24 hours to obtain an insulating part-forming material I-1.

[0223] [Measurement of weight average molecular weight of insulating part forming material I-1] The apparatus and conditions used to measure the weight average molecular weight (Mw) of the insulating portion forming material in this production example are as follows. First, the sample is dissolved in tetrahydrofuran (THF) at room temperature for 24 hours. The resulting solution is then filtered through a solvent-resistant membrane filter "Myshoridisc" (manufactured by Tosoh Corporation) with a pore size of 0.5 μm to obtain a sample solution. The sample solution is prepared so that the concentration is 0.5% by mass. This sample solution is measured under the following conditions. Apparatus: HLC-8320GPC (detector: RI) (manufactured by Tosoh Corporation) Column: Shodex LF-404, 2 columns of LF-404 (Showa Denko) Eluent: tetrahydrofuran (THF) Flow rate: 0.4ml / min Oven temperature: 40.0℃ Sample injection volume: 0.10 ml To calculate the molecular weight of a sample, a molecular weight calibration curve prepared using a standard polystyrene resin (for example, "EasiVial PS-H Polystyrene" manufactured by Agilent Technologies) is used. The molecular weight of the insulating portion forming material I-1 was measured and found to be Mw=56,000.

[0224] [1-5-2. Preparation and manufacturing of insulating material I-2] The acrylate monomers shown in Table 16 below were commercially available products. [Table 16]

[0225] <1-6. Example of manufacturing coating liquid for forming insulating parts> [1-6-1. Preparation of coating liquid J-1 for forming insulating parts] 100 parts by mass of the insulating portion forming material I-1 was weighed out, MEK was added to the material to give a concentration of 2.0 mass %, and the material was thoroughly dissolved to prepare insulating portion forming coating liquid J-1.

[0226] [1-6-2. Preparation of coating solutions J-2 to J-3 for forming insulating parts] In preparing the coating liquid J-1 for forming an insulating portion, coating liquids J-2 to J-3 for forming an insulating portion were prepared in the same manner as the coating liquid J-1 for forming an insulating portion, except that the materials and concentrations for forming the insulating portion were changed to those shown in Table 17 below.

[0227] [1-6-3. Preparation of coating solution J-4 for forming insulating parts] 100 parts by mass of the insulating part forming material I-2 was weighed out, and then 5.0 parts by mass of a photopolymerization initiator (product name: Omnirad184, manufactured by IGM Resins) was weighed out, and MEK was added to a concentration of 2.0% by mass, and the mixture was thoroughly dissolved to prepare insulating part forming coating liquid J-4. [Table 17]

[0228] <1-7. Manufacturing examples of developing rollers and comparative developing rollers> [1-7-1. Manufacturing example of developing roller K-1] The conductive layer roller G-1 was oriented with its longitudinal direction vertical, its upper end was gripped, and immersed (dipped) in the insulating portion-forming coating liquid J-1 to coat the surface of the conductive layer roller G-1 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 90°C. In this way, a developing roller K-1 was obtained, with an insulating portion formed on the conductive layer. The physical properties of the developing roller K-1 are shown in Tables 16-1 and 16-2.

[0229] [1-7-2. Manufacturing Examples of Developing Rollers K-2 to K-15] Developing rollers K-2 to K-15 were obtained in the same manner as in the manufacturing example of developing roller K-1, except that the conductive layer roller and the insulating portion-forming coating liquid were changed to those shown in Table 18-1 below. The physical properties of developing rollers K-2 to K-15 are shown in Tables 18-1 and 18-2.

[0230] [1-7-3. Manufacturing example of developing roller K-16] The conductive layer roller G-14 was oriented with its longitudinal direction in the vertical direction, and its upper end was gripped and immersed (dipped) in the insulating portion-forming coating liquid J-4 to coat the surface of the conductive layer roller G-14 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 90°C to obtain a conductive layer roller G-14 to which a mixture of the insulating portion-forming material and the photopolymerization initiator was attached. Thereafter, the outer surface of the conductive layer roller G-14 was exposed to an integrated light dose of 2000 mJ / cm 2 2 The insulating portion-forming material was cured by irradiating it with ultraviolet light so that the insulating portion was cured. In this way, a developing roller K-16 was obtained, in which an insulating portion was formed on the conductive layer. Note that a high-pressure mercury lamp (product name: handy type UV curing device, manufactured by Mario Network Co., Ltd.) was used as the ultraviolet irradiating device. The physical properties of the developing roller K-16 are shown in Tables 18-1 and 18-2. [Table 18-1] In the table, for example, 9.1E+06 is 9.1 x 10 6 The same applies to the other tables below. In addition, with regard to the impedance measurements of the developing rollers K-1 to K-16 and the comparative developing roller L-1, the minimum impedance value was 1.0×10 0 Hz~1.0×1 0 1 Indicates the minimum impedance value in Hz. [Table 18-2]

[0231] [1-7-4. Manufacturing example of comparative developing roller L-1] The conductive layer roller G-14 was used as the comparative developing roller L-1. The physical properties of the comparative developing roller L-1 are also shown in Tables 18-1 and 18-2. In addition, in the measurement of the surface potential of the comparative developing roller L-1, the surface potential was 0 V after 30.00 seconds to 100.00 seconds. INI The value of this was taken as the value of the surface potential of the conductive layer of the comparative developing roller L-1.

[0232] <2. Toner manufacturing example> <2-1. Example of toner particle production> [2-1-1. Production Example of Toner Particle P-1] [Production of charge control resin 1] To a pressurizable reaction vessel equipped with a reflux condenser, a stirrer, a thermometer, a nitrogen inlet tube, a dropping device, and a pressure reducing device, 250 parts of methanol, 150 parts of 2-butanone, and 100 parts of 2-propanol as solvents, and 83 parts of styrene, 12 parts of butyl acrylate, and 5 parts of 2-acrylamido-2-methylpropanesulfonic acid as monomers were added, and the mixture was heated to the reflux temperature with stirring. To this was added dropwise over 30 minutes a solution prepared by diluting 0.45 parts of t-butylperoxy-2-ethylhexanoate, a polymerization initiator, with 20 parts of 2-butanone, and stirring was continued for 5 hours. Further, a solution prepared by diluting 0.28 parts of t-butylperoxy-2-ethylhexanoate with 20 parts of 2-butanone was added dropwise over 30 minutes, and stirring was continued for a further 5 hours to complete the polymerization. The polymerization solvent was distilled off under reduced pressure, and the resulting polymer was coarsely pulverized to 100 μm or less using a cutter mill equipped with a 150 mesh screen to obtain charge control resin 1. The glass transition temperature (Tg) of the resulting polymer was approximately 70°C.

[0233] [Production of toner particles] In a four-necked container, add 710 parts of ion-exchanged water and 850 parts of a 0.1 mol / L Na3PO4 aqueous solution. The mixture was mixed for 200 seconds using a high-speed mixing device, TK Homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). -1 The mixture was stirred at 50° C. and maintained at 60° C. 68 parts of a 1.0 mol / L aqueous CaCl 2 solution was gradually added thereto to prepare an aqueous dispersion medium containing a dispersion stabilizer. Styrene: 125 parts n-Butyl acrylate: 35 parts Copper phthalocyanine pigment (Pigment Blue 15:3): 12 parts Polyester resin (terephthalic acid-propylene oxide modified bisphenol A (2 mole adduct) copolymer, acid value: 10 mg KOH / g, glass transition temperature (Tg): 70°C, weight average molecular weight (Mw): 10500): 10 parts Charge control resin 1: 1.85 parts Fischer-Tropsch wax (melting point: 78°C): 15 parts The above materials were stirred for 3 hours using an attritor (manufactured by Nippon Coke and Engineering Co., Ltd.) to disperse each component in the polymerizable monomer, thereby preparing a monomer mixture.

[0234] To the monomer mixture was added 20.0 parts of 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (50% toluene solution) as a polymerization initiator to prepare a polymerizable monomer composition. The polymerizable monomer composition was added to the aqueous dispersion medium, and the agitator was rotated at a speed of 167 s -1 After that, the high-speed agitator was replaced with a propeller agitator, the internal temperature was raised to 75°C, and the mixture was reacted for 6 hours with slow agitation. The temperature inside the container was then raised to 85°C and maintained for 5 hours, after which it was cooled to obtain a slurry. Dilute hydrochloric acid was added to the container containing the slurry to remove the dispersion stabilizer. The slurry was then filtered, washed, dried, and classified to obtain toner particles P-1.

[0235] [2-1-2. Production Example of Toner Particles P-2] [Production Example of Resin Particle Dispersion 1] Styrene: 350 parts n-Butyl acrylate: 75 parts Acrylic acid: 10 parts Dodecanethiol: 10 parts 420 parts of a solution containing the above materials and a solution of 6 parts of a nonionic surfactant (Nonipol 400, manufactured by Sanyo Chemical Industries, Ltd.) and 10 parts of an anionic surfactant (Neogen R, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) dissolved in 550 parts of ion-exchanged water were placed in a flask and dispersed and emulsified. While slowly stirring and mixing for 10 minutes, 50 parts of ion-exchanged water in which 4 parts of ammonium persulfate had been dissolved was added. The atmosphere in the flask was then thoroughly purged with nitrogen, and the system was heated in an oil bath with stirring until the temperature reached 70°C. Emulsion polymerization was continued for 5 hours, yielding Resin Particle Dispersion 1.

[0236] The volume average particle diameter (D50) of the resin fine particles in Resin Particle Dispersion 1 was measured to be 155 nm using a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.). The glass transition temperature of the resin was measured to be 54°C using a differential scanning calorimeter (DSC-50, manufactured by Shimadzu Corporation) at a heating rate of 10°C / min, and the weight average molecular weight (polystyrene equivalent) was measured to be 33,000 using a molecular weight analyzer (HLC-8020, manufactured by Tosoh Corporation) using THF as a solvent.

[0237] [Production Example of Resin Particle Dispersion 2] Styrene: 400 parts n-Butyl acrylate: 100 parts Acrylic acid: 4 parts n-Dodecyl mercaptan: 6 parts The above components were mixed to prepare a monomer solution, and an aqueous surfactant solution prepared by dissolving 10 g of anionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) in 1,130 g of ion-exchanged water and the monomer solution were added to a two-neck flask. The mixture was stirred at 10,000 r / min using a homogenizer (Ultra Turrax T50, manufactured by IKA Corporation) to emulsify the mixture. The atmosphere in the flask was then replaced with nitrogen, and the contents were heated to 70°C in a water bath with slow stirring. Then, 350 parts of ion-exchanged water containing 6.56 g of ammonium persulfate was added to initiate polymerization. After the reaction was continued for 7 hours, the reaction solution was cooled to room temperature. As a result, resin particle dispersion 2 was obtained.

[0238] The volume average particle diameter (D50) of the resin microparticles in resin microparticle dispersion 2 was measured using a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.) and was found to be 180 nm.The glass transition point of the resin was measured using a differential scanning calorimeter (DSC-50, manufactured by Shimadzu Corporation) at a heating rate of 10°C / min and was found to be 65°C.The weight average molecular weight (polystyrene equivalent) was measured using a molecular weight analyzer (HLC-8020, manufactured by Tosoh Corporation) using THF as a solvent and was found to be 26,000.

[0239] [Production of colorant particle dispersion] Cyan pigment (Pigment Blue 15:3, manufactured by Dainichi Seika Chemicals Co., Ltd.): 100.0 parts Anionic surfactant (Dai-ichi Kogyo Seiyaku Co., Ltd.: Neogen RK): 15.0 parts Ion-exchanged water: 885.0 parts The above ingredients were mixed and dissolved, and dispersed for about 1 hour using a high-pressure impact disperser Nanomizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.) to prepare a colorant particle dispersion (solid content concentration 10% by mass) in which the colorant particles were dispersed. The volume-based median diameter of the colorant particles was 0.2 μm.

[0240] [Production of wax microparticle dispersion] Ester wax (behenyl behenate, melting point 75°C): 100.0 parts Anionic surfactant (Dai-ichi Kogyo Seiyaku Co., Ltd.: Neogen RK): 10.0 parts Ion-exchanged water: 880.0 parts The above ingredients were placed in a container equipped with a stirrer, heated to 90°C, and circulated using a Clearmix W Motion (M Technique Co., Ltd.) at a rotor rotation speed of 310 s in a shear mixing section with a rotor outer diameter of 3 cm and clearance of 0.3 mm. -1 , screen rotation speed 310s -1 The mixture was stirred under the conditions of 33.3 s and dispersed for 60 minutes. -1 , Screen rotation speed 33.3s -1The mixture was cooled to 40°C at a cooling rate of 10°C / min to obtain a wax microparticle dispersion (solid concentration 10% by mass). The volume-based median diameter of the wax microparticles was 0.15µm.

[0241] [Formation of toner particles] ·Resin fine particle dispersion 1: 45.0 parts Colorant fine particle dispersion: 10.0 parts Wax microparticle dispersion: 15.0 parts 1% by mass calcium chloride aqueous solution: 20.0 parts Ion-exchanged water: 110.0 parts The above materials were mixed and dispersed using a homogenizer (IKA Ultra Turrax T50), and then heated to 45°C in a water bath while stirring with a stirring blade. The mixture was kept at 45°C for 1 hour to obtain an aqueous dispersion containing aggregated particles (aggregation step). The volume average particle size (Dv) of the aggregated particles was measured and found to be 5.7 μm.

[0242] After adding 40.0 parts of a 5% by mass aqueous solution of trisodium citrate to the aqueous dispersion, the mixture was heated to 85°C with continued stirring and maintained at this temperature for 120 minutes to obtain an aqueous dispersion containing fused core particles (primary fusion step). The volume average particle size (Dv) of the core particles was measured and found to be 6.4 µm. Ta. Next, while continuing to stir, water was added to the water bath and the aqueous dispersion of core particles was cooled to 25°C.

[0243] Next, 12.1 parts of Resin Fine Particle Dispersion 2 was added. After stirring for 10 minutes, 60.0 parts of a 2% by mass aqueous solution of calcium chloride was added dropwise, and the temperature was raised to 35° C. In this state, a small amount of the liquid was extracted from time to time and passed through a 2 μm microfilter, and stirring was continued at 35° C. until the filtrate became transparent. After the filtrate became transparent and it was confirmed that resin microparticles had adhered to the core particles and that shell-attached bodies had been formed, the aqueous dispersion of the shell-attached bodies was heated to 40°C and stirred for 1 hour, after which 35.0 parts of a 5% by mass aqueous solution of trisodium citrate was added, the temperature was raised to 65°C, and stirring was continued for 3.0 hours (secondary fusion process).

[0244] The resulting liquid was then cooled to 25°C, filtered and separated into solid and liquid, and 800 parts of ion-exchanged water was added to the solid matter, followed by stirring and washing for 30 minutes. Thereafter, filtration and solid-liquid separation were carried out again. In order to eliminate the influence of residual surfactant, the filtration and washing were repeated until the electrical conductivity of the filtrate became 150 μS / cm or less, and the obtained solid content was dried and classified to obtain toner particles P-2.

[0245] [2-1-3. Production Example of Toner Particle P-3] Toner particles P-3 were obtained in the same manner as in the production of toner particles P-2, except that the holding time at 85° C. in the primary fusion step of forming the toner particles was changed to 60 minutes.

[0246] [2-1-4. Production Example of Toner Particle P-4] Cyan pigment 6 parts (Pigment Blue 15:3, manufactured by Dainichi Seika Chemicals Co., Ltd.) Styrene-butyl acrylate-butyl maleate half ester copolymer (glass transition temperature Tg = 63°C) 100 parts · Iron complex of monoazo dye (negative charge control agent) 2 parts Low molecular weight polyethylene (DSC endothermic peak 106.7℃, Mw / Mn=1.08) 4 parts The above materials were mixed in a blender, then melt-kneaded in a twin-screw extruder heated to 110°C, the cooled kneaded mixture was coarsely pulverized in a hammer mill, the coarsely pulverized product was finely pulverized in a mechanical pulverizer, and the obtained finely pulverized product was classified to obtain toner particles P-4.

[0247] <2-2. Example of fine particle production> [2-2-1. Preparation of particles Q-1 to Q-8] The particles Q-1 to Q-8 used were commercially available products. The electrical conductivity of the particles is also shown in Table 19 below. [Table 19] In the table, the particle size indicates the number average particle size of the primary particles of the fine particles.

[0248] [2-2-2. Example of manufacturing fine particles Q-9] Ion-exchanged water: 100.0 parts Sodium phosphate (12-hydrate): 8.5 parts After mixing the above materials, 60.0 parts (equivalent to 7.2 parts as zirconium lactate ammonium salt) of zirconium lactate ammonium salt (ZC-300, Matsumoto Fine Chemical Co., Ltd.) was added at room temperature while stirring at 10,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). 1 mol / L of hydrochloric acid was added to adjust the pH to 7.0. The temperature was adjusted to 75°C, and the reaction was carried out for 1 hour while maintaining stirring. The solids were then separated by centrifugation. This process of redispersing in ion-exchanged water and separating the solids by centrifugation was repeated three times to remove ions such as sodium. The particles were again dispersed in ion-exchanged water and dried by spray drying to obtain zirconium phosphate microparticles Q-9 with a number-average particle size of 22 nm. The electrical conductivity of Q-9 is also shown in Table 19.

[0249] [2-2-3. Example of manufacturing fine particle Q-10] Ion-exchanged water: 100.0 parts Sodium phosphate (12-hydrate): 8.5 parts After mixing the above materials, 17.5 parts (equivalent to 7.2 parts of titanium lactate ammonium salt) of titanium lactate (TC-300, Matsumoto Fine Chemical Co., Ltd.) was added at room temperature while stirring at 10,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). 1 mol / L of hydrochloric acid was added to adjust the pH to 7.0. The temperature was adjusted to 75°C, and the reaction was carried out for 1 hour while maintaining stirring. The solids were then separated by centrifugation. This process of redispersing in ion-exchanged water and separating the solids by centrifugation was repeated three times to remove ions such as sodium. The particles were again dispersed in ion-exchanged water and dried by spray drying to obtain titanium phosphate microparticles Q-10 with a number-average particle size of 22 nm. The conductivity of Q-10 is also shown in Table 19 below.

[0250] [2-2-4. Preparation of external additive R-1] As the external additive R-1, commercially available fumed silica (RY200S, manufactured by Nippon Aerosil Co., Ltd.) was used. The conductivity of the external additive R-1 is also shown in Table 19.

[0251] <2-3. Toner manufacturing example> [2-3-1. Production of Toner S-1] Toner particles P-1 100 parts ·Particulate Q-1 3.0 parts External additive R-1 0.5 parts The above was externally added and mixed using an FM10C (manufactured by Nippon Coke and Engineering Co., Ltd.). The external addition conditions are: amount of toner particles: 1.8 kg, rotation speed: 60 s -1 The external addition time was 15 minutes. The mixture was then sieved through a mesh with 200 μm openings to obtain Toner S-1. The physical properties of Toner S-1 are shown in Table 20.

[0252] [2-3-2. Production of Toners S-2 to S-15] Toners S-2 to S-15 were produced in the same manner as Toner S-1, except that the types and amounts of toner particles, fine particles, and external additives were changed to those shown in Table 20. Table 20 shows their physical properties.

[0253] [2-3-3. Production of Comparative Toners T-1 to T-5] Comparative toners T-1 to T-5 were produced in the same manner as toner S-1, except that the types and amounts of toner particles, fine particles, and external additives were changed to those shown in Table 20. The physical properties are shown in Table 20. [Table 20]

[0254] <3. Manufacturing example of developing device> <3-1. Manufacturing example of developing device X-1> Toner cartridge 318 (cyan) (manufactured by Canon Inc.) was prepared as a process cartridge. Next, in order to reduce the torque of the developing device, the toner supply roller was removed from the developing device of the process cartridge. Furthermore, the developing roller was removed from the developing device, and developing roller K-1 was installed. In addition, the toner was removed from the developing device, and 70 g of toner S-1 was filled, and the developing device X-1 and the process cartridge having the developing device X-1 were installed. cartridges were manufactured.

[0255] <3-2. Manufacturing examples of developing devices X-2 to X-44> Developing devices X-2 to X-44 were manufactured in the same manner as developing device X-1, except that the developing roller and toner were changed to those shown in Table 21.

[0256] <3-3. Manufacture of comparative developing devices Y-1 to Y-6> Comparative developing devices Y-1 to Y-6 were manufactured in the same manner as developing device X-1, except that the developing roller (comparative developing roller) and toner (comparative toner) were changed to those shown in Table 21. [Table 21]

[0257] <4. Example> <4-1. Example 1> The evaluation methods and evaluation criteria of the present disclosure will be described 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 11. In addition to power supplies 14C and 15C, the modified apparatus was also connected to an external high-voltage power supply 20C, allowing any potential difference to be set between the developing blade and the developing roller.

[0258] The process cartridge used for evaluation was a process cartridge equipped with the above-mentioned developing device X-1. Furthermore, the product toner was removed from each of the yellow, magenta and black stations, and the yellow, magenta and black cartridges with the remaining toner amount detection mechanism disabled were inserted, and evaluation was performed. The work function of the developing blade (made of SUS304) attached to the developing device was 4.7 eV.

[0259] [Evaluation of initial ghost images and uneven density images in low temperature and low humidity environments] In a low-temperature, low-humidity environment, toner tends to build up due to friction with the contacting member. Therefore, when the toner supply roller is eliminated or the difference in peripheral speed between the toner supply roller and the developing roller is reduced, toner is less likely to be replaced from the developing roller, making ghost images more likely to occur. The above process cartridge, the modified laser printer, and evaluation paper (GFC81 (Canon) A4: 81.4 g / m 2 ) was left to stand for 24 hours in a low-temperature, low-humidity environment at a temperature of 15°C and a relative humidity of 10%. The process cartridge that had been left stationary was loaded into a modified laser printer, and the potential difference between the developing blade and the developing roller while the developing device was in operation was set to -300 V. The potential difference was set to -300 V at all times, including the timing corresponding to the interval between sheets of paper when an image was output, i.e., including the time when no image was being formed.

[0260] Under these conditions, five ghost evaluation images (images consisting of a 10mm wide all-black area from the leading edge in the image transport direction, a 2mm wide all-white area, and a 200mm 50% density halftone image) were printed consecutively. Note that 10mm in the image transport direction is narrower than one full rotation of the developing roller, and printing a 10mm wide all-black area results in most of the toner being developed in only a portion of the developing roller. If the toner on the developing roller cannot be spontaneously replaced, a difference in toner charge will occur between areas on the developing roller where toner has been consumed and areas where it has not, due to the difference in the number of times it has been rubbed. In this case, a density difference (ghost) will appear in the 50% density halftone area of ​​the ghost evaluation image in the same shape as the 10mm wide all-black area.

[0261] The images obtained were evaluated based on the following criteria, and the results are shown in Table 22 below. (Initial ghost image evaluation) Rank A: No ghosts are visible in any of the five images obtained. Rank B: A very slight ghost is visible in any of the five images obtained. Rank C: A slight ghost is visible in any of the five images obtained. Rank D: The ghost is clearly visible in one of the five images obtained.

[0262] [Evaluation of ghost images and uneven density images after durability testing in a low-temperature, low-humidity environment] As mentioned above, in a low-temperature, low-humidity environment, toner tends to charge up due to friction with the contacting member, making it difficult for the toner on the developing roller to be replaced, and ghost images are likely to occur. Furthermore, because the toner is difficult to replace, when the developing device is used for a long time, the toner on the developing roller continues to be repeatedly rubbed by the contacting member such as the developing blade. As a result, the toner deteriorates and melts onto the developing roller. When the toner is fused, the charge amount and transport amount of the toner on the developing roller become uneven, which appears as a hazy image with uneven density. Furthermore, in a low-temperature, low-humidity environment, toner components, particularly fine particles such as external additives, tend to adhere to the developing roller due to wear, and the charge series with the toner and developing blade tends to change.

[0263] The above process cartridge, the modified laser printer, and evaluation paper (GFC81 (Canon) A4: 81.4 g / m 2 ) was left to stand for 24 hours in a low-temperature, low-humidity environment at a temperature of 15°C and a relative humidity of 10%. The process cartridge was then loaded into a modified laser printer, and the potential difference between the developing blade and the developing roller was set to -300 V, the same as that between sheets of paper being output, i.e., even during non-image formation. Under these conditions, 20,000 images with a print rate of 2% were output.

[0264] Next, five images for evaluating ghosting (images consisting of a 10 mm wide all-black image from the leading edge in the image conveyance direction, a 2 mm wide all-white image, and a 200 mm halftone image with a density of 50%) were output in succession. The images obtained were evaluated based on the following criteria, and the results are shown in Table 22 below.

[0265] (Ghost image evaluation after durability test) Rank A: No ghosts are visible in any of the five images. Rank B: A very slight ghost is visible in one of the five images. Rank C: A slight ghost is visible in one of the five images. Rank D: The ghost is clearly visible in one of the five images.

[0266] (Evaluation of image density unevenness after durability testing) Rank A: No visible density unevenness in the halftone area in any of the five images. Rank B: Very slight density unevenness is visible in the halftone area of ​​any of the five images. Rank C: Slight density unevenness is visible in the halftone area in any of the five images. Rank D: Density unevenness is clearly visible in the halftone area in any of the five images.

[0267] [Evaluation of toner transport performance under high temperature and humidity conditions] In a high-temperature, high-humidity environment, the insulating portion of the developing roller is less likely to become charged. Therefore, the amount of toner transported by the developing roller tends to decrease, especially when the toner supply roller is eliminated or the difference in peripheral speed between the toner supply roller and the developing roller is reduced. When the amount of toner transported decreases, the image density decreases toward the rear edge of the printed image when printing an all-black image.

[0268] The above process cartridge, the modified laser printer, and evaluation paper (GFC81 (Canon) A4: 81.4 g / m 2 ) was left to stand in a high temperature and high humidity environment of 30°C and 80% relative humidity for 24 hours. The process cartridge placed in the above environment was loaded into a modified laser printer, and the potential difference between the developing blade and the developing roller while the developing device was in operation was set to −300 V. Under these conditions, one all-black image was output. The density of the obtained all-black image was measured using a spectrodensitometer (product name: X-Rite504, manufactured by S.D.G. Co., Ltd.). The image density difference was calculated by dividing the arithmetic mean value of the image densities at five points within 20.0 mm from the leading edge of the image in the conveying direction by the arithmetic mean value of the image densities at five points within 20.0 mm from the trailing edge of the image in the conveying direction.

[0269] The images obtained were evaluated based on the following criteria, and the results are shown in Table 22 below. (Evaluation of image density unevenness after durability testing) Rank A: Image density difference is less than 0.10 Rank B: Image density difference is 0.10 or more and less than 0.20 Rank C: Image density difference is 0.20 or more and less than 0.30 Rank D: Image density difference is 0.30 or more

[0270] <4-2. Examples 2 to 44 and Comparative Examples 1 to 6> Except for using developing devices X-2 to X-44 and comparative developing devices Y-1 to Y-6, evaluation was carried out in the same manner as in Example 1. The evaluation results are shown in Table 22 below. [Table 22] *In Comparative Example 3, poor transferability due to excessive reduction in toner charge prevented the toner from being sufficiently transported to the evaluation paper, making it impossible to evaluate the image.

[0271] From the above results, by using the developing device of the present disclosure, even when the driving torque of the developing device is reduced, it is possible to perform the development without relying on the control of the potential difference between the developing roller and the developing blade during non-image formation. Therefore, it is possible to suppress the occurrence of ghost images, images with uneven density, and toner transport defects.

[0272] The present disclosure includes the following configurations. (Configuration 1) A developing device having a developing roller and toner, The developing roller is a substrate having an electrically conductive outer surface; a conductive layer on the outer surface of the substrate; the outer surface of the developing roller is composed of at least a first region and a second region having a higher conductivity than the first region; the first region and the second region are disposed adjacent to each other; the first region is disposed on an outer surface of the conductive layer; The toner includes toner particles and fine particles having a compound containing a metal element, the metal element is at least one element selected from the group consisting of titanium, aluminum, zirconium, and zinc, when the toner surface is measured by X-ray photoelectron spectroscopy, the abundance ratio of the metal element is 2.0 to 20.0 atomic %; The developing device is characterized in that the toner has an average circularity of 0.970 or more. (Configuration 2) The conductivity of the particles determined by impedance measurement is 1.0 × 10 -9 ~1.0×10 2 2. The developing device according to claim 1, wherein the density is S / m. (Configuration 3) When an EDS mapping image of constituent elements of a cross section of the toner is obtained by analyzing the cross section of the toner observed with a scanning transmission electron microscope with an energy dispersive X-ray spectrometer, The developing device according to Structure 1 or 2, wherein the number average length of the fine particles having the signal derived from the metal element in the normal direction to the outline of the toner particle at the contact point between the fine particles having the signal derived from the metal element and the toner particle is 0.01 to 0.50 μm. (Structure 4) 4. The developing device according to any one of configurations 1 to 3, wherein the compound containing a metal element is at least one selected from the group consisting of titanium oxide, aluminum oxide, zinc oxide, strontium titanate, zirconium phosphate, and titanium phosphate. (Configuration 5) A developing device according to any one of configurations 1 to 4, wherein when a square observation area with a side length of 300 μm is placed on the outer surface of the developing roller so that one side of the observation area is parallel to the axial direction of the developing roller, the ratio of the total area of ​​the first area to the area of ​​the square observation area is 10 to 60 area %. (Configuration 6) In an environment of a temperature of 23°C and a relative humidity of 50%, a corona discharger having a grid portion with a width of 3.0 mm was arranged so that the distance between the grid portion and the outer surface of the developing roller was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developing roller, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developing roller at a speed of 400 mm / sec to charge the outer surface of the developing roller, and the potential of the outer surface was measured t seconds after the grid portion had passed. The change in potential in the range of 30.00≦t≦100.00 was fitted to the following equation (X′) by the least squares method, and V 0,1The developing device according to any one of configurations 1 to 5, wherein when [V] and τ1 [seconds] are calculated, τ1 is 60.0 seconds or more: V1(t)=V 0,1 exp(-t / τ1) (X'). (Configuration 7) A corona with a grid section of 3.0 mm in width was used under an environment of 23°C and 50% relative humidity. The discharger was disposed so that the distance between the grid portion and the outer surface of the developing roller was 1.0 mm and the width direction of the grid portion coincided with the axial direction of the developing roller, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developing roller at a speed of 400 mm / sec to charge the outer surface of the developing roller, and the potential of the outer surface was measured t seconds after the grid portion had passed. The change in potential in the range of 30.00≦t≦100.00 was fitted to the following equation (X′) by the least squares method, and V 0,1 The developing device according to any one of configurations 1 to 6, wherein when [V] and τ1 [seconds] are calculated, when the value of potential V1(t) obtained by substituting t=0.06 [seconds] into formula (X') is V1 [V], V1 is 5.0 V or more: V1(t)=V 0,1 exp(-t / τ1) (X'). (Configuration 8) In an environment of a temperature of 23°C and a relative humidity of 50%, a corona discharger having a grid portion with a width of 3.0 mm was arranged so that the distance between the grid portion and the outer surface of the developing roller was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developing roller, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developing roller at a speed of 400 mm / sec to charge the outer surface of the developing roller, and the potential of the outer surface was measured t seconds after the grid portion had passed. The potential at t=0.06 [seconds] is V INI [V], The change in potential in the range of 30.00≦t≦100.00 was fitted to the following equation (X′) by the least squares method, and V 0,1When [V] and τ1 [seconds] are calculated, when t = 0.06 [seconds] is substituted into the formula (X'), the value of the potential V1(t) is V1 [V], INI The developing device according to any one of Configurations 1 to 7, wherein −V1 is less than 20.0 V: V1(t)=V 0,1 exp(-t / τ1) (X'). (Configuration 9) In an environment of a temperature of 23°C and a relative humidity of 50%, a corona discharger having a grid portion with a width of 3.0 mm was arranged so that the distance between the grid portion and the outer surface of the developing roller was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developing roller, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developing roller at a speed of 400 mm / sec to charge the outer surface of the developing roller, and the potential of the outer surface was measured t seconds after the grid portion had passed. The change in potential in the range of 0.06≦t≦100.00 was fitted to the following equation (Y) by the least squares method, and V 0,2 When [V] and τ2 [seconds] are calculated, The developing device according to any one of Configurations 1 to 8, wherein τ2 is 6.0 seconds or less: V(t)=V1(t)+V2(t) (Y) (In formula (Y), V2(t)=V 0,2 exp(-t / τ2) (Z)) (Configuration 10) A metal film was provided directly on the outer surface of the developing roller, 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%. An AC voltage of 50 V amplitude was applied at 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 1.0×10 6 10. The developing device according to any one of configurations 1 to 9, wherein the resistance is Ω or more. (Configuration 11) 11. The developing device according to any one of configurations 1 to 10, wherein the conductive layer contains polyurethane. (Configuration 12) 12. The developing device according to any one of configurations 1 to 11, wherein the conductive layer contains polyurethane having a polycarbonate structure. (Configuration 13) 13. The developing device according to claim 12, 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, in its molecule, either one or both of a structure represented by the following structural formula (2) and a structure represented by the following structural formula (3): (C) The polyurethane has a structure represented by the following structural formula (4) in the molecule. TIFF2026042319000027.tif102170 [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 14) The developing device according to any one of Configurations 1 to 13, wherein the conductive layer contains carbon black. (Configuration 15) The developing device according to any one of Structures 1 to 14, wherein the conductive layer contains at least one selected from the group consisting of a compound represented by the following structural formula (5), a compound represented by the following structural formula (6), and a compound represented by the following structural formula (7): TIFF2026042319000028.tif77170 In structural formula (5), R51 represents a monovalent hydrocarbon group having 1 to 12 carbon atoms. t and u represent the average number of moles added, and each independently represents a number of 1.0 or more. In structural formula (6), R61 represents a monovalent hydrocarbon group having 1 to 8 carbon atoms, v and w represent the average number of moles added, and each independently represents a number of 1.0 or more. In structural formula (7), R71 represents a monovalent hydrocarbon group having 1 to 12 carbon atoms, and x represents the average number of moles added and is a number of 1.0 or more. (Configuration 16) A process cartridge configured to be detachably attached to the main body of an electrophotographic image forming apparatus, the process cartridge comprising a developing means, the developing means having the developing device according to any one of configurations 1 to 15. (Configuration 17) 16. An electrophotographic image forming apparatus equipped with a developing means, wherein the developing means comprises the developing device according to any one of Configurations 1 to 15.

Claims

1. A developing device having a developing roller and toner, The developing roller is a substrate having an electrically conductive outer surface; a conductive layer on the outer surface of the substrate; the outer surface of the developing roller is composed of at least a first region and a second region having a higher conductivity than the first region; the first region and the second region are disposed adjacent to each other; the first region is disposed on an outer surface of the conductive layer; The toner includes toner particles and fine particles having a compound containing a metal element, the metal element is at least one element selected from the group consisting of titanium, aluminum, zirconium, and zinc, when the toner surface is measured by X-ray photoelectron spectroscopy, the content of the metal element is 2.0 to 20.0 atomic %; The developing device is characterized in that the toner has an average circularity of 0.970 or more.

2. The conductivity of the fine particles determined by impedance measurement is 1.0 × 10 －９ ~1.0 x 10 ２ 2. The developing device according to claim 1, wherein the toner density is S / m.

3. When an EDS mapping image of constituent elements of the cross section of the toner is obtained by analyzing the cross section of the toner observed with a scanning transmission electron microscope with an energy dispersive X-ray spectrometer, 2. The developing device according to claim 1, wherein the number average length of the fine particles having the signal derived from the metal element in the normal direction to the outline of the toner particle at the contact point between the fine particles having the signal derived from the metal element and the toner particle is 0.01 to 0.50 μm.

4. 2. The developing device according to claim 1, wherein the compound containing a metal element is at least one selected from the group consisting of titanium oxide, aluminum oxide, zinc oxide, strontium titanate, zirconium phosphate, and titanium phosphate.

5. 2. The developing device according to claim 1, wherein when a square observation area with a side of 300 μm is placed on the outer surface of the developing roller so that one side of the observation area is parallel to the axial direction of the developing roller, the ratio of the total area of ​​the first area to the area of ​​the square observation area is 10 to 60 area %.

6. In an environment of a temperature of 23°C and a relative humidity of 50%, a corona discharger having a grid portion with a width of 3.0 mm was arranged so that the distance between the grid portion and the outer surface of the developing roller was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developing roller, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developing roller at a speed of 400 mm / sec to charge the outer surface of the developing roller, and the potential of the outer surface was measured t seconds after the grid portion had passed. The change in potential in the range of 30.00≦t≦100.00 was fitted to the following equation (X′) by the least squares method, and V ０，１ [V] and τ １ When [seconds] is calculated, τ １ 2. The developing device according to claim 1, wherein the time is 60.0 seconds or more. V １ (t)=V ０，１ exp(-t / τ １ ) (X’)。

7. In an environment of a temperature of 23°C and a relative humidity of 50%, a corona discharger having a grid portion with a width of 3.0 mm was placed so that the distance between the grid portion and the outer surface of the developing roller was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developing roller. A voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developing roller at a speed of 400 mm / sec to charge the outer surface of the developing roller, and the potential of the outer surface was measured t seconds after the grid portion had passed. The change in potential in the range of 30.00≦t≦100.00 was fitted to the following equation (X′) by the least squares method, and V ０，１ [V] and τ １ When t = 0.06 [seconds] is calculated, the potential V when t = 0.06 [seconds] is substituted into the formula (X') １ (t) value V １ When [V] is set, V １ 2. The developing device according to claim 1, wherein the voltage Vcc is 5.0 V or more. V １ (t)=V ０，１ exp(-t / τ １ ) (X’)。

8. In an environment of a temperature of 23°C and a relative humidity of 50%, a corona discharger having a grid portion with a width of 3.0 mm was arranged so that the distance between the grid portion and the outer surface of the developing roller was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developing roller, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developing roller at a speed of 400 mm / sec to charge the outer surface of the developing roller, and the potential of the outer surface was measured t seconds after the grid portion had passed. The potential at t = 0.06 [seconds] is V ＩＮＩ [V], The change in potential in the range of 30.00≦t≦100.00 was fitted to the following equation (X′) by the least squares method, and V ０，１ [V] and τ １ When t = 0.06 [seconds] is calculated, the potential V when t = 0.06 [seconds] is substituted into the formula (X') １ (t) value V １ When [V] is set, V ＩＮＩ -V １ 2. The developing device of claim 1, wherein: V １ (t)=V ０，１ exp(-t / τ １ ) (X’)。

9. In an environment of a temperature of 23°C and a relative humidity of 50%, a corona discharger having a grid portion with a width of 3.0 mm was arranged so that the distance between the grid portion and the outer surface of the developing roller was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developing roller, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developing roller at a speed of 400 mm / sec to charge the outer surface of the developing roller, and the potential of the outer surface was measured t seconds after the grid portion had passed. The change in potential in the range of 0.06≦t≦100.00 was fitted to the following equation (Y) by the least squares method, and V ０，２ [V] and τ ２ When calculating [seconds], The τ ２ 2. The developing device of claim 1, wherein the time is 6.0 seconds or less. V(t)=V １ (t)+V ２ (t) (Y) (In formula (Y), V ２ (t) = V ０，２ exp(−t / τ ２ ) (Z))

10. A metal film was provided directly on the outer surface of the developing roller, 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 x 10 ５ When applied while changing between 1.0 x 10 Hz, ０ ~1.0 x 10 １ Impedance at Hz is 1.0 x 10 ６ 2. The developing device according to claim 1, wherein the resistance is Ω or more.

11. 10. The development system of claim 1, wherein said conductive layer comprises polyurethane.

12. 2. The development system of claim 1, wherein said conductive layer comprises a polyurethane having a polycarbonate structure.

13. The developing device according to claim 12, 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, in its molecule, either one or both of a structure represented by the following structural formula (2) and a structure represented by the following structural formula (3): (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.

14. 10. The development apparatus of claim 1, wherein said conductive layer comprises carbon black.

15. 12. The developing device according to claim 11, wherein the conductive layer contains at least one selected from the group consisting of a compound represented by the following structural formula (5), a compound represented by the following structural formula (6), and a compound represented by the following structural formula (7): In structural formula (5), R51 represents a monovalent hydrocarbon group having 1 to 12 carbon atoms. t and u represent the average number of moles added, and each independently represents a number of 1.0 or more. In structural formula (6), R61 represents a monovalent hydrocarbon group having 1 to 8 carbon atoms, v and w represent the average number of moles added, and each independently represents a number of 1.0 or more. In structural formula (7), R71 represents a monovalent hydrocarbon group having 1 to 12 carbon atoms, and x represents the average number of moles added and is a number of 1.0 or more.

16. A process cartridge configured to be detachably mountable to a main body of an electrophotographic image forming apparatus, the process cartridge comprising a developing means, the developing means having the developing device according to any one of claims 1 to 15.

17. 16. An electrophotographic image forming apparatus comprising a developing means, the developing means comprising the developing device according to any one of claims 1 to 15.

Images