Process cartridge and image forming apparatus

Abstract

To provide an image forming apparatus capable of effectively injecting electric charges to toner over a long term.SOLUTION: The image forming apparatus includes a developer carrier, a developer container storing developer including developer particles and the developer carrier, a developing blade, an image carrier, and a charging member, the developer carrier includes a base body having a conductive outer surface and a resin layer on the outer surface, and the resin layer includes polyurethane having a polycarbonate structure. In the image forming apparatus, the developer carrier has an impedance within a predetermined range when measured by a predetermined method, the maximum value of the potential of the outer surface is less than a predetermined value, the surface of the developer particles is covered with surface particles having a predetermined conductivity, the coverage of the surface particles is 35% or more, and the fixing rate is 80% or more.SELECTED DRAWING: Figure 9

Description

[Technical Field]

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

[0002] In recent years, there has been a demand for high image quality and durability in printers and copiers. In particular, there is a demand for printers to be more compact and less wasteful.

[0003] Focusing on the cleaning device, cleanerless systems, which do not have a cleaning device at all, are extremely suitable for miniaturizing process cartridges. In many printers, toner remaining on the electrostatic latent image carrier during the transfer process is scraped off by a cleaning blade or the like and collected in a cleaning container as waste toner. In contrast, cleanerless systems do not have a cleaning blade or cleaning container, and the remaining toner after transfer is collected in the developing device and contributes to development again. This allows for a significant miniaturization of process cartridges, and also contributes greatly to reducing waste by not generating waste toner.

[0004] However, cleanerless systems also present unique challenges. One of these is that toner deformation over time can make it difficult to charge, resulting in residual toner buildup in the developing device and potentially causing image defects. Conventionally, frictional charging, in which toner is charged by rubbing against a regulating member or other component, is widely used as a toner charging process. However, as mentioned above, deformed toner that develops over time tends to lose its charge due to insufficient friction. This can lead to image defects known as "fog," in which non-image areas develop irregularly. This fog phenomenon is particularly prevalent under high temperature and humidity conditions, where the toner's charge is relatively low.

[0005] To address this decline in toner charge due to long-term use, the injection process is being considered. The injection process is a process in which a charge is injected into the toner by using the potential difference between the toner and a component such as a regulating member. In this case, if there is a conductive path in the toner, it is possible to impart a charge to the entire toner without rubbing it.

[0006] Patent Document 1 proposes an injection process in which a conductive toner and an injection member are used to inject a charge into the toner. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-058745 Summary of the Invention [Problem to be solved by the invention]

[0008] However, Patent Document 1 has the following problems. In Patent Document 1, the surface of a low-resistivity conductive toner is coated with an insulating film, and when the electric field strength is strong, the resistance of the toner drops significantly, allowing charge to be injected into the toner. However, because the insulating film on the surface of the conductive toner or the resistance of the developing roller is affected by the environment, the amount of charge injected into the toner changes or the charge injected into the toner leaks, which can make it impossible to impart sufficient charge to the toner. In particular, in high-temperature, high-humidity environments, the charge injected into the toner often leaks.

[0009] In addition, the charge injected into the toner may decrease after long-term use. This is because the state of the insulating film on the surface of the conductive toner changes over time, causing the charge injected into the toner to decrease. As such, even with injection systems, there was a problem in that the fogging phenomenon occurred significantly when used in high-temperature, high-humidity environments or for long periods of time.

[0010] SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide an image forming apparatus that can inject charge into toner effectively for a long period of time. [Means for solving the problem]

[0011] In order to solve the above problems, the process cartridge according to the present application comprises: a developer carrier that carries a developer; a developer container that contains the developer carrier and a developer containing developer particles; a developing blade that regulates the developer on the developer carrier; an image carrier that carries a developer image; a charging member for charging the image bearing member; A process cartridge comprising: the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface of the substrate, the resin layer contains polyurethane having a polycarbonate structure, A metal film was provided directly on the outer surface of the developer carrier, and a DC voltage of 50 V was applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%. 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 1.00 x 10 6 is greater than or equal to Ω, and 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 disposed so that the distance between the grid portion and the outer surface of the developer carrier was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developer carrier, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier, and the maximum value of the potential of the outer surface was measured 0.06 seconds after the grid portion had passed, and the maximum value of the potential was less than 20.0 V, The surface of the developer particles has a conductivity of 1×10 -15 S / m or more The surface is coated with surface particles, the surface particle coverage is 35% or more, and the surface particle adhesion rate is 80% or more; applying a voltage to the developing blade with a predetermined potential difference relative to the developer bearing member, the predetermined potential difference being the same polarity as the normal charging polarity of the developer; It is characterized by:

[0012] In order to solve the above problems, the process cartridge according to the present application comprises: a developer carrier that carries a developer; a developer container that contains the developer carrier and a developer containing developer particles; a developing blade that regulates the developer on the developer carrier; an image carrier that carries a developer image; a charging member for charging the image bearing member; A process cartridge comprising: the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface of the substrate, the resin layer contains polyurethane having a polycarbonate structure, A metal film was provided directly on the outer surface of the developer carrier, and a DC voltage of 50 V was applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%. An AC voltage of 50 V amplitude was applied at a frequency of 1.0×10 -1 ~1.0×105 When applied while changing between Hz, the frequency is 1.0 × 10 0 ~1.0×10 1 Impedance at 1 Hz .00×10 6 is greater than or equal to Ω, and 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 disposed so that the distance between the grid portion and the outer surface of the developer carrier was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developer carrier, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier, and the maximum value of the potential of the outer surface was measured 0.06 seconds after the grid portion had passed, and the maximum value of the potential was less than 20.0 V, The surface of the developer particles has a conductivity of 1×10 -15 S / m or more The substrate is coated with an organosilicon polymer, the coverage of the organosilicon polymer being 35% or more, and the adhesion rate of the organosilicon polymer being 80% or more. applying a voltage to the developing blade with a predetermined potential difference relative to the developer bearing member, the predetermined potential difference being the same polarity as the normal charging polarity of the developer; It is characterized by:

[0013] In order to solve the above problems, the image forming apparatus according to the present application comprises: a developer carrier that carries a developer; a developer container that contains the developer carrier and a developer containing developer particles; a developing blade that regulates the developer on the developer carrier; an image carrier that carries a developer image; a charging member for charging the image bearing member; an exposure device that exposes the image carrier; a transfer member for transferring the developer image formed on the image carrier; An image forming apparatus comprising: the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface of the substrate, the resin layer contains polyurethane having a polycarbonate structure, a metal film is provided directly on the outer surface of the developer carrier, and when a DC voltage of 50 V is applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%, and an AC voltage having an amplitude of 50 V is applied while changing the frequency between 1.0×10 Hz and 1.0×10 Hz, the impedance at a frequency of 1.0×10 Hz to 1.0×10 Hz is 1.00×10 Ω or more; and 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 disposed so that the distance between the grid portion and the outer surface of the developer carrier was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developer carrier, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier, and the maximum value of the potential of the outer surface was measured 0.06 seconds after the grid portion had passed, and the maximum value of the potential was less than 20.0 V, The surface of the developer particles has a conductivity of 1×10 −15 S / m or more, which is different from that of the developer matrix. The surface is coated with surface particles, the surface particle coverage is 35% or more, and the surface particle adhesion rate is 80% or more; applying a voltage to the developing blade with a predetermined potential difference relative to the developer bearing member, the predetermined potential difference being the same polarity as the normal charging polarity of the developer; It is characterized by:

[0014] In order to solve the above problems, the image forming apparatus according to the present application comprises: a developer carrier that carries a developer; a developer container that contains the developer carrier and a developer containing developer particles; a developing blade that regulates the developer on the developer carrier; an image carrier that carries a developer image; a charging member for charging the image bearing member; an exposure device that exposes the image carrier; a transfer member for transferring the developer image formed on the image carrier; An image forming apparatus comprising: the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface of the substrate, the resin layer contains polyurethane having a polycarbonate structure, a metal film is provided directly on the outer surface of the developer carrier, and when a DC voltage of 50 V is applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%, and an AC voltage having an amplitude of 50 V is applied while changing the frequency between 1.0×10 Hz and 1.0×10 Hz, the impedance at a frequency of 1.0×10 Hz to 1.0×10 Hz is 1.00×10 Ω or more; and 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 disposed so that the distance between the grid portion and the outer surface of the developer carrier was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developer carrier, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier, and the maximum value of the potential of the outer surface was measured 0.06 seconds after the grid portion had passed, and the maximum value of the potential was less than 20.0 V, The surface of the developer particles has a conductivity of 1×10 −15 S / m or more, which is different from that of the developer matrix. The substrate is coated with an organosilicon polymer, the coverage of the organosilicon polymer being 35% or more, and the adhesion rate of the organosilicon polymer being 80% or more. applying a voltage to the developing blade with a predetermined potential difference relative to the developer bearing member, the predetermined potential difference being the same polarity as the normal charging polarity of the developer; It is characterized by: [Effects of the Invention]

[0015] According to the present invention, it is possible to provide an image forming apparatus that can inject charge into toner effectively for a long period of time. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic cross-sectional view showing an example of an image forming apparatus according to a first embodiment of the present invention; [Figure 2] 1 is a schematic cross-sectional view showing an example of a process cartridge according to a first embodiment. [Figure 3] Schematic cross-sectional view showing an example of a developing roller in Example 1. [Figure 4] FIG. 10 is a schematic cross-sectional view showing another example of the developing roller in the first embodiment. [Figure 5] Schematic diagram of a state in which a measurement electrode is formed on a developing roller in Example 1. [Figure 6] Cross-sectional view of the developing roller and the measurement electrode in Example 1 [Figure 7] Schematic diagram of the impedance measurement system in Example 1 [Figure 8] FIG. 1 is a schematic diagram showing an example of an apparatus for measuring the surface potential of a developing roller in the first embodiment. [Figure 9] Schematic diagram of a circuit for measuring leakage current flowing from toner to the developing roller [Figure 10] Schematic diagram of a toner conductivity measurement system in Example 1 [Figure 11] Diagram showing the influence of the impedance of the developer roller and the conductivity of the surface particles [Figure 12] Graph showing the effect of the irregularity degree on the evaluation value of the toner [Figure 13] Diagram showing the effect on the amount of charge per unit area [Figure 14] Diagram showing the effect on the amount of charge per unit area DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, preferred embodiments of the present invention will be described in detail by way of example with reference to the drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described in the following embodiments are not necessarily the same as those of the present invention. The present invention should be modified as appropriate depending on the configuration of the device to which the invention is applied and various conditions. Therefore, unless otherwise specified, it is not intended to limit the scope of the present invention. Although multiple features are described in the examples, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily.

[0018] In the present disclosure, expressions such as "XX or more and YY or less" or "XX to YY" representing a numerical range mean a numerical range including the upper and lower limits, which are the endpoints, unless otherwise specified. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined arbitrarily. Furthermore, in the present disclosure, expressions such as "at least one selected from the group consisting of XX, YY, and ZZ" mean any of XX, YY, ZZ, a combination of XX and YY, a combination of XX and ZZ, a combination of YY and ZZ, or a combination of XX, YY, and ZZ.

[0019] The present inventors believe that the details of how the above-mentioned means solve the problems are as follows.

[0020] First, the present inventors investigated the physical properties of toner suitable for the charging process in order to solve the above-mentioned problem. As a result, they found that the surface of the toner particles (developer particles) has a conductivity of 1×10, which is different from that of the toner matrix (developer matrix). -15 Surface particles of S / m or more or organosilicon polymers It was found that by covering the toner with a coverage of 35% or more, electric charges can be effectively injected into the toner from components such as the developing blade. -15 S / m or more It is speculated that the surface particles or organosilicon polymers function as conductive paths and also as charging sites, and that by increasing the coverage rate above a certain level, the opportunities for contact between the charging sites of toner particles increases, resulting in an effective transfer of charge between toner particles.

[0021] Furthermore, it was found that if the surface particles or organosilicon polymers are fixed to the toner particles to an adhesion rate of 80% or more, charge can be injected into the toner for a long period of time, resulting in good images. As mentioned above, this result is thought to be due to the fact that the surface particles or organosilicon polymers function as conductive paths and charging sites, and that by being fixed to the toner particles, they can maintain this function for a long period of time.

[0022] Furthermore, in order to address the above-mentioned issues, the inventors considered combining a developing roller having a surface layer formed using polyurethane having only a polycarbonate structure (hereinafter referred to as polycarbonate urethane) with a developing blade to which a high voltage is applied.

[0023] As a result, although it was possible to prevent charge leakage from the toner to the developing roller, the electrical resistance of the surface layer became too high, which created a new problem: excessively charged toner adhered to the surface of the developing roller.

[0024] Therefore, the present inventors have investigated ways to remove excess charge from overcharged toner. For example, they have investigated the inclusion of a conductive filler in the surface layer, but have discovered a new problem: it is difficult to disperse the conductive filler well in polycarbonate urethane. If the conductive filler is not sufficiently dispersible, a conductive path is formed by the conductive filler in the surface layer, causing charge leakage, or conversely, the effect of removing excess charge expected from the conductive filler may be insufficient.

[0025] That is, in order to solve at a high level the conflicting problems of preventing charge leakage from toner in the surface layer containing polycarbonate urethane and removing the excess charge from the overcharged toner, it is necessary to maintain high electrical resistance of the surface layer while being able to remove the excess charge. The present inventors recognized that the development of such a new surface layer was necessary. Based on this recognition, the present inventors conducted further studies.

[0026] As a result, the inventors have recognized that satisfying the following two requirements for a developing roller (developer carrier) having a substrate with a conductive outer surface and a resin layer containing polyurethane having a polycarbonate structure on the outer surface of the substrate is effective in resolving the above two conflicting issues at a high level.

[0027] 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 The frequency is changed between 1.0×10 Hz. 0 ~1.0×10 1 Impedance at Hz is 1.00×10 6 It is greater than or equal to Ω.

[0028] Requirement (2) In an environment of 23°C temperature and 50% relative humidity, a corona charger with a 3.0 mm wide grid was placed 1.0 mm away from the outer surface of the developing roller, with the grid's width aligned with the axial direction of the developing roller. A voltage of 8 kV was applied to the grid, and the corona charger 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. The potential of the outer surface was measured 0.06 seconds after the grid passed. The maximum potential was less than 20.0 V.

[0029] The above requirements (1) and (2) are explained in detail below.

[0030] <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 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. 9. 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.

[0031] This shows that when it comes to charge leakage, it is necessary to consider not only the resistance component of the developing roller but also the effect 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 accumulates in the capacitance component and the steady state dominated by the resistance component has a large effect on charge leakage.

[0032] 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.

[0033] Impedance exhibits bias dependency, and has the property of decreasing as the bias increases, but it is known that the degree of decrease varies depending on the developing roller. In conventional impedance measurements of developing rollers, a voltage application condition of 1 V AC is generally used, but this condition of 1 V AC 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 difficult to simulate the behavior of the developing roller in an electrophotographic image forming apparatus. In many cases, the conditions are not suitable for impedance measurement.

[0034] 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 1 The low frequency range of 1.0 x 10 Hz is the region where the transient state is completed and the steady state dominated by the resistance component is reached. In other words, the influence of both the capacitance component and the resistance component is reflected, and this region is suitable for understanding the charge leakage from the toner to the developing roller. 0 ~1.0×10 1 Impedance at Hz is 1.00×10 6 When the resistance is Ω or more, the charge leakage is low, and under a high blade bias, charge leakage from the toner to the developing roller is suppressed, and a decrease in the charge amount of the toner can be prevented, which results in suppression of fogging and good image density stability.

[0036] The frequency is 1.0 x 10 0 ~1.0×10 1 The impedance in Hz is preferably 1.40 x 10 6 The higher the impedance value, the better. There is no particular upper limit, but for example, 5.00×10 7 Examples include Ω and below.

[0037] Also, the frequency is 1.0 x 10 0 ~1.0×10 1 The minimum impedance in Hz is preferably 1.40 x 10 6 Ω or more, more preferably 2.00×10 6Ω or more, particularly preferably 3.00×10 6 Ω or more, more preferably 5.00×10 6 The preferred range of the impedance is 1.00×10 6 Ω or more 5.00×10 7 Ω or less, preferably 1.40×10 6 Ω or more 5.00×10 7 Ω or less, more preferably 2.00×10 6 Ω or more 5.00×10 7 Ω or less, particularly preferably 3.00 × 10 6 Ω or more 5.00×10 7 Ω or less, more preferably 5.00×10 6 Ω or more 5.00×10 7 It is less than Ω.

[0038] <Technical significance of requirement (2)> Requirement (2) specifies the surface potential of the developing roller. The surface potential of the developing roller indicates the residual charge on the surface of the developing roller, and is a physical property that indicates the degree of excessive charge (charge-up) of the toner. If the surface potential is high, the charge of the excessively charged toner cannot be properly controlled, which may result in a decrease in image density or the occurrence of fogging.

[0039] There are two possible causes of a decrease in image density. The first is that excessively charged toner adheres electrically to the surface of the developing roller, making it impossible to charge the next toner transported to the same location. The second is that after the toner is removed from the surface of the developing roller, residual charge remains on the surface of the developing roller, making it impossible to charge the next toner transported to the same location.

[0040] In this disclosure, a voltage of 8 kV is applied to the grid portion, and a corona discharger is moved relative to the developing roller in the axial direction at a speed of 400 mm / s. The potential of the outer surface of the developing roller is measured 0.06 seconds after the grid portion of the corona discharger passes. If the maximum value of the outer surface potential is less than 20.0 V, the occurrence of image defects due to excessive toner charging can be suppressed even in electrophotographic image forming devices with high process speeds, where the time it takes for toner charged by the developing blade to be transported to the photoconductor is shorter. Note that the measurement 0.06 seconds after the grid portion of the corona discharger passes simulates a model with a high process speed.

[0041] The maximum value of the potential of the outer surface is preferably 15.0 V or less, more preferably 10 The lower the maximum value of the potential of the outer surface, the more preferable it is, and there is no particular lower limit.

[0042] A preferred range for the maximum potential of the outer surface is, for example, 0 V or more and less than 20.0 V, particularly 0 V or more and 15.0 V or less, and further preferably 0 V or more and 10.0 V or less.

[0043] By satisfying the above requirements (1) and (2), it is possible to solve at a high level the conflicting problems of preventing charge leakage from the toner to the developing roller and removing excess charge from overcharged toner.

[0044] There are no particular limitations on the means for satisfying the above requirements (1) and (2). Specific examples of the means for improving the dispersibility of the conductive filler include, as will be described later, the following resin layer materials, conductive filler materials, and additives.

[0045] There are no particular limitations on the means for satisfying the above requirements (1) and (2). Specific examples of the means for improving the dispersibility of the conductive filler include, as will be described later, the following resin layer materials, conductive filler materials, and additives.

[0046] Preferred embodiments of the present invention will now be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the following embodiments may be changed as appropriate depending on the configuration of the device to which the present invention is applied and various conditions. Therefore, unless otherwise specified, they are not intended to limit the scope of the present invention. Although the embodiments describe multiple features, not all of these features are necessarily essential to the invention, and multiple features may be combined in any desired manner.

[0047] [Example 1] 1. Image forming device FIG. 1 is a schematic diagram of an image forming apparatus 100 of this embodiment. The image forming apparatus 100 of this embodiment is an electrophotographic laser printer that can form an image on a recording material P (transfer material) according to image information input from an external device 200 such as a personal computer. The recording material P includes various sheet materials of different materials, such as paper such as plain paper, cardboard, and talc paper, plastic film such as sheets for overhead projectors, sheets of special shapes such as envelopes and index paper, and cloth. First, the configuration of the image forming apparatus 100 of this embodiment will be described.

[0048] The image forming device 100 includes a scanner unit 11, an electrophotographic process cartridge 20 that is detachably attached to the image forming device 100, an image forming section consisting of a transfer roller 12 that transfers a toner image formed on a photosensitive drum 21 in the process cartridge 20 onto a recording material P, a recording material feeding section that transports the recording material P to the transfer section in conjunction with the operation of the image forming section, a fixing device 40 that fixes the toner image formed on the recording material P in the transfer section onto the recording material P, and a control section 150 that controls the operation of the image forming device.

[0049] When an image formation command is input to the image forming apparatus 100, the image forming unit starts an image forming process based on image information input from an external device 200 such as a personal computer connected to the image forming apparatus 100.

[0050] The control unit 150 is a control means that comprehensively controls the operation of the image forming apparatus 100. The control unit 150 controls the transmission and reception of various electrical information signals, drive timing, etc., and executes a predetermined image formation sequence. Each unit of the image forming apparatus 100 is connected to the control unit 150. For example, in relation to this embodiment, the control unit 150 is connected to a charging power supply E1, a developing power supply E2, a transfer power supply E3, a brush power supply E4, a blade power supply E5, a supply roller power supply E6, a scanner unit 11 (exposure unit), a power supply for the fixing device, a drive motor, and the like.

[0051] [Image forming section] As shown in FIG. 2, the process cartridge 20 has a developing device 30. The developing device 30 includes a developing roller 31 as a developer carrier that carries developer, a developing container 32 that forms the frame of the developing device 30, a supply roller 33 that can supply developer to the developing roller 31, a stirring member 34 that stirs the toner serving as the developer in the developing container 32, and a developing blade 35 that uniformly distributes the toner layer on the developing roller 31. The developing roller 31, the supply roller 33, and the stirring member 34 are rotatably supported by the developing container 32. The developing roller 31 is disposed at the opening of the developing container 32 so as to face the photosensitive drum 21 serving as an image carrier. The supply roller 33 rotatably contacts the developing roller 31, and the toner serving as the developer contained in the developing container 32 is applied to the surface of the developing roller 31 by the supply roller 33.

[0052] An agitating member 34 serving as a stirring means is provided inside the developing container 32. When driven to rotate, the agitating member 34 agitates the toner in the developing container 32 and sends the toner toward the developing roller 31 and the supply roller 33. The agitating member 34 also circulates, within the developing container, the toner that has been scraped off from the developing roller 31 and not used in development, thereby serving to homogenize the toner in the developing container.

[0053] A developing blade 35 made of a stainless steel plate that regulates the amount of toner carried by the developing roller 31 is disposed at the opening of the developing container 32 in which the developing roller 31 is disposed.

[0054] The developer supplied to the surface of the developing roller 31 passes through the opposing portion with the developing blade 35 as the developing roller 31 rotates, whereby the developer is uniformly thinned and given an amount of charge suitable for image formation. Note that, although this embodiment has been described as a form in which the photosensitive drum 21 is housed in the process cartridge 20, the developing device 30 may also be configured to be detachable from the main body of the apparatus.

[0055] The developing device 30 of this embodiment uses a contact development method. That is, the toner layer carried on the developing roller 31 comes into contact with the photosensitive drum 21 in a developing section (developing area Pd) where the photosensitive drum 21 and the developing roller 31 face each other. A developing voltage is applied to the developing roller 31 by a developing power supply E2, which is a developing voltage application section. A blade voltage, which is a developing blade application voltage, is applied to the developing blade 35 by a blade power supply E5. Furthermore, a supply voltage is applied to the supply roller 33 by a supply roller power supply E6, which is a supply voltage application section. This allows the charge amount of the developer to be controlled to a state appropriate for image formation. A common supply source can be used for these voltage application sections as needed.

[0056] A voltage is applied to the developing blade with a predetermined potential difference relative to the developer bearing member, and the predetermined potential difference has the same polarity as the normal charging polarity of the developer.

[0057] As a result, when the toner passes through the opposing portion between the developing roller 31 and the developing blade 35, charge is injected from the developing blade 35 into the toner. The applied blade voltage is preferably 150 V or more and 400 V or less in absolute value relative to the developing voltage. By applying a blade voltage of 150 V or more in absolute value, sufficient charge can be injected into the toner. On the other hand, a voltage of 400 V or more is not preferable because current may leak at the end of the developing blade 35.

[0058] Furthermore, the inventors discovered that the effective difference in blade voltage relative to the development voltage varies depending on the process speed, and that a higher blade voltage is preferable as the process speed decreases. The inventors speculate that the following factors contribute to this result: As the developing roller 31 rotates, a portion of the toner carried on the developing roller 31 is blocked by the developing blade 35 in the area immediately before the rotation of the developing roller 31. The blocked toner moves upward from the developing roller 31 or in the opposite direction to the rotation of the developing roller 31, resulting in toner circulation. However, when the rotation speed of the developing roller 31 is slow, the amount of toner blocked per unit time is small, making it difficult for toner to circulate. As a result, the toner carried on the developing roller 31 passes through the area between the developing roller 31 and the developing blade 35 in a loose state. The inventors speculate that a loose toner particle makes it difficult for charge to be transferred between toner particles, and therefore requires a higher blade voltage to charge the entire toner particle. On the other hand, when the rotation speed of the developing roller 31 is high, a large amount of toner is held up per unit time, which makes it easier for the toner to circulate and causes the toner carried on the developing roller 31 to change from a sparse state to a dense state. When the toner is in a dense state, charge is effectively transferred between the toner particles, and it is speculated that a charge can be imparted to the entire toner even with a low blade voltage.

[0059] The toner carried by the developing roller 31 is transferred from the developing roller 31 to the surface of the photosensitive drum 21 in accordance with the surface potential of the photosensitive drum 21, thereby developing the electrostatic latent image into a toner image. In this embodiment, the surface of the developing roller 31 is set to -300 V by the developing power supply E2. -300 V is applied to the supply roller power supply E6. Furthermore, a reversal development method is adopted in which the drum surface potential is uniformly charged to -500 V by the charging unit described below, and then the printing unit exposes the drum surface potential to a scanner unit described below, attenuating the drum surface potential, and negatively charged toner adheres to the exposed area. The back contrast Vback, which is the absolute value of the potential difference between the surface of the photosensitive drum 21 in the non-exposed area Vd and the developing roller 31 before passing through the development area, is 200 V.

[0060] In this embodiment, the ratio of the surface speed of the developing roller 31 to the surface speed of the photosensitive drum 21 (hereinafter referred to as the developing peripheral speed ratio) is 140%. That is, in this example, the process speed for printing in normal mode is 150 mm / sec (surface speed of the photosensitive drum 21), and the developing roller 31 rotates at 150 x 1.4 = 210 mm / sec.

[0061] The photosensitive drum 21 is a cylindrically shaped photosensitive member. The photosensitive drum 21, which serves as an image carrier, is rotated by a motor (not shown) in a predetermined direction (clockwise in FIGS. 1 and 2) at a predetermined process speed.

[0062] The paper dust collecting brush 22 and the charging roller 23 contact the photosensitive drum 21 with a predetermined pressure. A predetermined charging roller voltage is applied to the charging roller 23 from the charging power source E1, thereby uniformly charging the surface of the photosensitive drum 21 to a predetermined potential. In this embodiment, the drum surface potential is charged to -500 V by the charging roller 23. Furthermore, by using the pre-exposure device 24 to uniformize the drum surface potential after transfer in advance, the drum surface potential can be made more uniform when the photosensitive drum is charged by the charging roller 23.

[0063] A given brush voltage is applied to the paper dust collection brush 22 from the brush power supply E4, and the brush 22 collects paper fibers and paper dust that have detached from the recording material P and adhered to the photosensitive drum. This prevents the paper fibers and paper dust from interfering with the charging of the photosensitive drum when they pass through the charging section.

[0064] The scanner unit 11, which is an exposure unit, uses a polygon mirror to irradiate the photosensitive drum 21 with laser light L corresponding to image information input from an external device, thereby scanning and exposing the surface of the photosensitive drum 21. An electrostatic latent image is formed. The scanner unit 11 is not limited to a laser scanner device, and may be, for example, an LED exposure device having an LED array in which a plurality of LEDs are arranged along the longitudinal direction of the photosensitive drum 21. In this embodiment, the laser exposure of the scanner unit 11 attenuates the drum surface potential (exposed area Vl) of the solid black area to -50V.

[0065] [Recovery of residual toner after transfer] This embodiment employs a so-called cleanerless configuration in which residual toner remaining on the photosensitive drum 21 without being transferred to the recording material P is collected in the developing device 30 and reused. The residual toner is reused in the following process. The residual toner includes a mixture of toner that is positively charged, which is the opposite polarity to the normal polarity in this embodiment, and toner that is negatively charged but does not have a sufficient charge.

[0066] By charging the toner to the normal polarity again when it passes through the paper dust collecting brush 22 and just before the contact point between the charging roller 23 and the photosensitive drum 21, the residual toner does not adhere to the charging roller 23 and is transported with the rotation of the photosensitive drum 21. As a result, the charging roller 23 can maintain good charging performance.

[0067] The transfer residual toner adhering to the surface of the photosensitive drum 21 that has passed through the contact area with the paper dust collecting brush 22 and the contact area with the charging roller 23 reaches the development area Pd as the photosensitive drum 21 rotates. Here, the behavior of the transfer residual toner that has reached the development area will be described separately for the exposed area and the non-exposed area of ​​the photosensitive drum 21. In the non-exposed area of ​​the photosensitive drum 21, i.e., the dark potential Vd area, the surface potential of the photosensitive drum 21 is more negative than the development voltage applied to the development roller 31. Therefore, the transfer residual toner that has a sufficient negative charge moves to the development roller 31 due to Coulomb force caused by the electric field and is collected in the developer container 32. Here, the dark potential Vd of the photosensitive drum 21 is not limited to the non-exposed area. If the surface potential of the photosensitive drum 21 is more negative than the development voltage applied to the development roller 31, weak exposure may be performed to adjust the surface potential to an appropriate Vback.

[0068] The toner collected in the developing container 32 is stirred and dispersed with the toner in the developing container 32 by the stirring member 34, and is carried by the developing roller 31 so as to be used again in the developing process.

[0069] On the other hand, at the exposed portion Vl of the photosensitive drum 21, the surface potential of the photosensitive drum 21 is smaller on the negative side than the development voltage applied to the development roller 31, and therefore the transfer residual toner does not transfer from the photosensitive drum 21 to the development roller 31 at the development portion, but remains on the surface of the photosensitive drum 21. The transfer residual toner remaining on the surface of the photosensitive drum 21 is carried by the photosensitive drum 21 together with other toner transferred from the development roller 31 to the exposed portion, and moves to the transfer portion, where it is transferred to the recording material P.

[0070] [Recording material feeding section] In parallel with the image formation process described above, recording material P stored in paper tray 7, which serves as a recording material storage unit, is fed out in accordance with the timing of the transfer of the toner image. To explain the process of conveying recording material P, first, paper feed roller 8 feeds out recording material P stored in paper tray 7. Next, recording material P is fed by paper feed roller 8 to pair of conveying rollers 9, and skew is corrected when recording material P hits the nip of pair of conveying rollers 9. Then, based on the detection result of the leading edge of recording material P in the conveying direction by top sensor 10, which serves as recording material detection means, the pair of conveying rollers 9 is driven in accordance with the timing of the transfer of the toner image, and conveys recording material P along conveying guide 15 toward the transfer nip formed by transfer roller 12 and photosensitive drum 21.

[0071] An electric field is formed by a transfer power source E3 on the transfer roller 12 in a direction that moves the normally charged toner from the photosensitive drum toward the transfer roller at the transfer nip. The toner image formed on the photosensitive drum 21 is transferred to the recording material P by conveying the recording material P to the transfer nip in accordance with the image formation timing.

[0072] The recording material P onto which the toner image has been transferred has excess charge on its surface removed by a charge removal needle 19. The recording material P that has passed through the charge removal needle 19 is transported to a fixing device 40 along a transfer / fixing transport guide 16 that serves as a guide member.

[0073] [Fixing section] The recording material P transported along the transfer-fixing transport guide 16 is transported to the fixing device 40. The fixing device 40 includes a fixing film 41, a fixing heater such as a ceramic heater that heats the fixing film 41, a thermistor that measures the temperature of the fixing heater, and a pressure roller 42 that presses against the fixing film 41. When the recording material P passes between the fixing film 41 and the pressure roller 42, the toner on the recording material P is heated and pressurized, and is fixed to the recording material P.

[0074] The recording material P that has passed through the fixing device 40 is discharged to the outside of the image forming apparatus 100 by a pair of discharge rollers 13 and is stacked on a discharge tray 14. The discharge tray 14 is inclined upward toward the downstream side in the discharge direction of the recording material, and the recording material discharged onto the discharge tray 14 slides down the discharge tray 14, and its trailing edge is aligned by a regulating surface 17.

[0075] In this embodiment, the process cartridge 20 is detachably mounted to the image forming apparatus main body, but the present invention is not limited to this and any process cartridge capable of carrying out a predetermined image forming process may be used. For example, a developing cartridge with a detachable developing device 30, a drum cartridge with a detachable drum unit, a toner cartridge that supplies toner to the developing device 30 from an external source, or a configuration that does not use a detachable cartridge may be used.

[0076] 2. Developing roller The developing roller 31 as a developer carrier will be described below with reference to the drawings. The developing roller according to at least one embodiment of the present disclosure has a conductive substrate and at least one resin layer on the outer peripheral surface of the substrate.

[0077] An example of a developing roller is shown in Fig. 3. The developing roller 31 shown in Fig. 3 has a resin layer 312 laminated on the outer peripheral surface of a columnar or hollow cylindrical base 311. Note that the layer configuration of the developing roller is not limited to the form shown in Fig. 3.

[0078] As another embodiment of the developing roller, as shown in FIG. 4, an elastic layer 313 may be provided between a base body 311 and a resin layer 312 provided on the outer circumferential surface thereof.

[0079] [Base] The substrate has a conductive outer surface and functions as a support member for the developing roller and, in some cases, as an electrode. Specific examples of the substrate preferably have a solid columnar or hollow cylindrical shape.

[0080] The material for the substrate can be appropriately selected from those known in the field of electroconductive members for electrophotography and materials usable as such developer carriers, and examples thereof include metals or alloys such as aluminum and stainless steel, carbon steel alloys, conductive synthetic resins, iron, and copper alloys.

[0081] Furthermore, the material that makes up the base is subjected to oxidation treatment or plating with chrome, nickel, etc. The plating may be either electroplating or electroless plating. From the viewpoint of dimensional stability, electroless plating is preferred.

[0082] The types of electroless plating 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.

[0083] A primer may be applied to the surface of the substrate to improve adhesion between the substrate and the resin layer. A known primer can be selected and used depending on the rubber material for forming the conductive layer and the material of the support. Examples of primer materials include thermosetting resins and thermoplastic resins, and specific examples of materials that can be used include phenolic resins, polyurethanes, acrylic resins, polyester resins, polyether resins, and epoxy resins.

[0084] [Resin layer] The developing roller has a resin layer on the outer surface of a substrate. For example, the resin layer is present on the outer surface of a developer carrier. The resin layer may contain a binder resin. It is preferable to use polyurethane having a polycarbonate structure as the binder resin of the resin layer in the developing roller in order to suppress charge leakage from the toner to the developing roller. That is, the resin layer contains polyurethane having a polycarbonate structure. Furthermore, in order to suppress charge leakage from the toner to the developing roller while maintaining a light load on the toner and sufficient wear resistance of the resin layer, it is more preferable to use polyurethane having the structure described below as the binder resin of the resin layer.

[0085] The resin layer contains polyurethane having a polycarbonate structure, 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.

[0086] 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)

[0087] Among these, from the viewpoint of better fogging suppression and image density stability, it is more preferable that the polyurethane has at least the structure represented by structural formula (1) and the structure represented by structural formula (4) in the molecule. [ka]

[0088] 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).

[0089] 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).

[0090] 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).

[0091] 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).

[0092] The structure shown in structural formula (1) is a copolymer polycarbonate polyol in which crystallinity is suppressed by linking two carbonate groups with two different hydrocarbon groups, and the polyol is reacted with isocyanate. Because the crystallinity is suppressed, the cohesive energy in the soft segments is small, which gives the resin layer flexibility and high volume resistivity.

[0093] By using the structure of structural formula (1) in combination with the structures (2) to (4) described above in the resin layer, the adhesiveness of the resin layer can be reduced, which prevents toner, powder, etc. from adhering to the surface of the resin layer, suppresses an increase in the electrical resistance of the surface of the resin layer due to contamination, and facilitates uniform charging of the toner.

[0094] 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.

[0095] If the number of carbon atoms in R11 and R12 is 3 or more, the amount of carbonate groups, which are polar functional groups with strong cohesive energy, in the polyurethane having a polycarbonate structure will not be too large, making it easier to maintain the resin layer flexible and with a high electrical resistance.

[0096] Furthermore, when the carbon numbers of R11 and R12 are 9 or less, the amount of carbonate groups in the polyurethane is not too small, and the strength of the polymer can be maintained. Furthermore, when R11 and R12 have different structures, the crystallinity of the polymer can be suppressed and flexibility can be imparted to the resin layer. m and n each independently represent a number of 1.0 or more. The hydrocarbon groups represented by R11, R12, and R13 may have a branched structure or a cyclic structure.

[0097] The structures shown in structural formulas (2) and (3) are obtained by reacting a copolymer polyol, which is a copolymer of a polycarbonate structure and a polyester structure, with an isocyanate. By copolymerizing a polycarbonate structure and a polyester structure, the crystallinity of the polymer is suppressed, and by introducing an ester group, which has a stronger cohesive energy than a carbonate group, the soft segment is appropriately reinforced, thereby imparting abrasion resistance to the resin layer.

[0098] When a resin layer is formed using a polymer in which the structure represented by structural formula (2) and / or structural formula (3) is combined with the structure represented by formula (1) or (4), the resin layer can be endowed with sufficient volume resistivity while having a polar ester group, making it easier to suppress charge leakage from the toner to the developing roller.

[0099] In structural formula (2), o and p each independently represent a number of 1.0 or more.

[0100] In structural formula (3), R31 and R32 each independently represent a divalent hydrocarbon group having 3 to 8 carbon atoms, and q and r each independently represent a number greater than or equal to 1.0. When R31 and R32 each have 3 or more carbon atoms, the amount of carbonate groups and ester groups in the polyurethane, which are polar functional groups with strong cohesive energy, is not too large, thereby maintaining flexibility of the resin layer. When R31 and R32 each have 8 or less carbon atoms, the amount of carbonate groups and ester groups in the polyurethane is not too small, thereby providing abrasion resistance to the resin layer.

[0101] The structure shown in structural formula (4) is a structure obtained by reacting a highly crystalline polycarbonate polyol, in which two carbonate groups are bonded by a single hydrocarbon group, with an isocyanate. This structure is highly crystalline and easily oriented in the soft segment, imparting abrasion resistance and high volume resistivity to the resin layer. By forming a resin layer using a polymer that combines the structure shown in structural formula (4) with the structures of formulas (1) to (3) described above, the hardness of the resin layer is not excessively high and can be easily controlled appropriately.

[0102] In structural formula (4), R41 represents a divalent hydrocarbon group having 6 to 9 carbon atoms, and s represents a number of 1.0 or more. When R41 has 6 or more carbon atoms, crystallinity is easily exhibited, and the resin layer can be provided with abrasion resistance and high volume resistivity. When R41 has 9 or less carbon atoms, excessive Since the crystallinity can be suppressed, by further containing at least one of the structures represented by structural formulas (1), (2) and (3) in the polymer, an increase in the hardness of the resin layer can be suppressed.

[0103] The resin layer preferably contains a polymer having a urethane bond, i.e., a polyurethane having a polycarbonate structure, as a binder resin, and the polymer preferably satisfies at least two selected from the group consisting of (A), (B), and (C) above, which makes the resin layer flexible and less susceptible to wear.

[0104] The structure of the polymer contained in the resin layer of the developing roller can be confirmed by, for example, pyrolysis GC / MS, FT-IR, or NMR analysis.

[0105] Polyurethanes having a polycarbonate structure can be produced using (A) a polyol compound and (B) a polyisocyanate compound. Polyurethanes are usually synthesized by the following methods (1) and (2). (1) 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.

[0106] 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.

[0107] The polyurethane having a polycarbonate structure is preferably a reaction product of a mixture containing a hydroxyl-terminated prepolymer and an isocyanate-terminated prepolymer. The mixture can be used as a coating liquid for forming a resin layer. The polyurethane having a polycarbonate structure is more preferably a reaction product of a mixture containing a hydroxyl-terminated prepolymer, an isocyanate-terminated prepolymer, a conductive filler, and an additive.

[0108] When there are many hydroxyl groups, isocyanate groups, or urea bonds, allophanate bonds, isocyanurate bonds, etc., the polyurethane contains many polar functional groups, which increases the water absorption of the polymer and reduces the volume resistivity of the resin layer, potentially leading to charge leakage from the toner to the developing roller.On the other hand, by thermally curing the hydroxyl-terminated prepolymer and the isocyanate-terminated prepolymer, it is possible to obtain a polyurethane with little unreacted polyol or polar functional groups without using an excessive amount of isocyanate.

[0109] (A) Polyol compound The polyol is selected from known polycarbonate polyols and polyester-polycarbonate copolymer polyols.

[0110] 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.

[0111] Examples of polyester polycarbonate copolymer polyols include the following: copolymers obtained by polycondensation of 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;

[0112] (B) Polyisocyanate compound The polyisocyanate may be selected from commonly used and known polyisocyanates, such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymeric diphenylmethane polyisocyanate, hydrogenated MDI, polymeric MDI, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPDI). Among these, aromatic isocyanates such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymeric diphenylmethane polyisocyanate, and polymeric MDI are more preferably used. Other polyisocyanates may also be used as long as they do not affect the impedance value and surface potential.

[0113] 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.

[0114] The content of polyurethane in the resin 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.

[0115] (Conductive filler) The resin layer preferably contains a conductive filler to obtain conductivity. It is more preferable to use an electronic conductive agent as the conductive filler in the resin layer. The electronic conductive agent is preferably a conductive particle that exhibits electronic conductivity and has a surface functional group that can interact with a functional group present in the additive described below.

[0116] 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.

[0117] Among these, at least one selected from the group consisting of carbon blacks with highly stable surface functional groups is preferably used. The conductive filler preferably contains carbon black. Furthermore, in order to obtain the desired impedance value and surface potential, carbon black having a number-average diameter of primary particles of 30 nm or less, which allows for higher dispersion in the resin layer, a DBP absorption of 90 ml / 100 g or less, and a pH of 4.0 or less is particularly preferably used.

[0118] 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, and the desired impedance may not be obtained. 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.

[0119] 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.

[0120] 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.

[0121] 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, relative to 100 parts by mass of polyurethane forming the resin layer.

[0122] When the amount is 30 parts by mass or less, the distance between carbon black particles in the coating solution is maintained at an appropriate level, reducing the probability of collisions due to Brownian motion and other factors, making the carbon black less likely to aggregate. This facilitates dispersion of the carbon black, and improves dispersion stability. As a result, the carbon black is well dispersed in the resin layer formed by coating the coating solution. Furthermore, if the carbon black surface is coated with an insulating material such as a silane coupling agent, it will no longer behave as a pseudo-capacitor, resulting in high impedance and surface potential. Furthermore, multiple types of carbon black may be used in combination as long as the impedance and surface potential are not affected.

[0123] (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, a compound having a structure represented by the following structural formula (5) can be suitably used as the additive. One method for incorporating the additive into the surface layer is to incorporate a dispersant into a coating liquid for forming a surface layer. Note that in a surface layer formed using a coating liquid for forming a surface layer containing a compound having a structure represented by structural formula (5), the compound may be incorporated at the end of the polyurethane polymer chain. Even in such cases, the effect of improving the dispersibility of carbon black can be expected, but it is preferable for the compound to be present in the surface layer independently of the polyurethane.

[0124] [ka]

[0125] In structural formula (5), R51 is a monovalent hydrocarbon group having 1 to 12 carbon atoms (preferably 3 to 12). t and u are the average number of moles added, and each independently represents a number of 1 or more (preferably 5 to 30, more preferably 10 to 25).

[0126] 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.

[0127] Ethylene oxide is introduced into the structure to ensure uniform distribution of the additive in the polycarbonate urethane. This is thought to be because the ethylene group in ethylene oxide is compatible with the hydrophobic hydrocarbon group in the polycarbonate urethane. Propylene oxide is introduced into the structure to improve the dispersibility of the conductive filler dispersed in the resin layer. This is thought to be because the side-chain methyl group of propylene oxide interacts with the conductive filler, improving the dispersibility of the conductive filler.

[0128] 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.

[0129] 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.

[0130] 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). Step (A): Reaction of alcohol with ethylene oxide Step (B): Reaction of the product obtained in step (A) with propylene oxide

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] The compound represented by structural formula (5) functions as a dispersant for carbon black and has high affinity with polycarbonate urethane. Surfactants are typically used to improve the dispersibility and dispersion stability of carbon black. However, the compound represented by structural formula (5) has a low number of functional groups that interact with the surface functional groups of carbon black, resulting in a weak surfactant effect and making it uncommonly used. Coupling agents and nonionic surfactants are commonly used as dispersants for carbon black.

[0136] 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.

[0137] The amount of the compound represented by structural formula (5) added is preferably 3.0 to 7.0 mass % based on the solid content in the coating material for forming a surface layer, more preferably 3.0 to 5.0 mass %, and the total content is preferably 18.9 to 46.0 mass parts relative to 100 mass parts of carbon black in the coating material for forming a surface layer.

[0138] By ensuring that the content of the additive in the coating material for forming the surface layer is within the above range, the dispersibility of the carbon black in the polyurethane is further improved, and the desired impedance value and surface potential can be more easily achieved.

[0139] The presence of additives in the resin layer can be confirmed and quantitatively evaluated by the following analytical method: By cutting out the resin layer of the developing roller and using, for example, 1H-NMR, 13CNMR, XPS, or FT-IR on the slice, the carbonate structure of the binder resin and the ether structure, amine structure, and carboxylic acid structure of the additive can be detected in the resin layer, and the ratio can be calculated from the peak ratio, etc.

[0140] Alternatively, sections can be extracted by immersing them overnight in an organic solvent such as 2-butanone (methyl ethyl ketone; MEK), and the extract and the extracted sections can be analyzed. 1 H-NMR, 13 By using C-NMR, XPS, and FT-IR, it is possible to calculate the ratio of additives that are incorporated into the resin during the polymerization reaction and those that are not.

[0141] (roughening particles) The resin 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.

[0142] 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.

[0143] The developing roller may have an elastic layer on the outer surface of the substrate. For example, the developing roller has an elastic layer between the substrate and the resin layer. The elastic layer is not particularly limited, and any layer known as an elastic layer for a developer carrier may be used. For example, a cured product of an addition-curing liquid silicone rubber mixture may be used.

[0144] [Manufacturing method] The method for forming the resin layer is not particularly limited, but examples include spraying with a paint, dip coating, and roll coating. For example, a resin layer can be formed by applying a resin 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 heating and drying conditions are not particularly limited, and examples include a method of drying at 120 to 200°C. The thickness of the resin layer is also not particularly limited, and is preferably 1 to 50 μm, and more preferably 5 to 20 μm.

[0145] [Method for measuring various characteristics of developer carriers] (impedance) In impedance measurements, 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 relative to the applied AC voltage, and one with a phase shift of π / 2. The impedance of the response with no phase shift is plotted on a complex plane as Z' (real part), and the impedance of the response with a phase shift is plotted as Z" (imaginary part), and the distance from the origin to the plot is calculated as the impedance value.

[0146] 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.

[0147] The impedance measurement method, measurement device, and measurement conditions are described below.

[0148] Impedance measurement method 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.

[0149] 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.

[0150] When measuring impedance, the influence of the contact resistance between the developing roller and the measurement electrode is eliminated. To achieve this, 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 with two terminals, with the conductive substrate as a ground electrode.

[0151] Examples of methods for forming the thin film include metal deposition, sputtering, applying a metal paste, and attaching a metal tape. Among these, from the viewpoint of reducing contact resistance with the developer carrier, a method of forming a metal thin film such as platinum or palladium as an electrode by vapor deposition is preferred. In the present disclosure, vacuum platinum vapor deposition is used.

[0152] 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.

[0153] 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.

[0154] Impedance measurement equipment and measurement conditions The impedance measurement equipment is an impedance analyzer, a network analyzer, a spectrum analyzer, etc., and is 1.0 x 10 -1 ~1.0×10 5 Any device capable of measuring impedance in a frequency range up to 100 Hz will suffice. Among these, it is preferable to measure the impedance using an impedance analyzer in the electrical resistance range of the developing roller.

[0155] The impedance measurement conditions are as follows: An impedance measurement device was used, and the impedance was measured at 1.0 x 10 -1 ~1.0×10 5 The impedance is measured in the frequency range of 100 Hz. The measurement environment is a temperature of 23°C and a relative humidity of 50%. To account for measurement variations, it is preferable to measure at least nine points in total: three points along the length of the developer carrier and three points in the rotational direction. The voltage application condition is a DC voltage of 50 V superimposed on an AC voltage of 50 V.

[0156] (surface potential) 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 axial direction of the developing roller at a speed of 400 mm / s to charge the outer surface of the developing roller. The potential of the outer surface 0.06 seconds after passing the grid was measured, and the susceptibility of the developing roller surface to excessive charging (charge-up) was evaluated. The surface potential of the developing roller can be measured, for example, by the device shown in FIG.

[0157] Both ends of substrate 82 of developing roller 81 are held by chucks 83, and a measuring unit 86, in which a corona discharger 84 and a surface electrometer 85 are arranged in parallel with an interval of 25 mm, is placed opposite 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., and the surface potential is measured by surface electrometer 85 0.06 seconds after passing through corona discharger 84.

[0158] The meaning of the measurement conditions and measurement values ​​has been explained in the above section <Technical significance of requirement (2)>, so it will not be covered here.

[0159] The present invention will be described in more detail below, but the present invention is not limited thereto.

[0160] [2-1. Preparation and manufacturing of raw materials for forming resin layer] <2-1-1. Preparation of raw polyol and manufacturing example> A synthesis example for obtaining a polyurethane resin layer will be shown below.

[0161] [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. Measurement equipment: 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

[0162] 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.

[0163] 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.

[0164] [Preparing raw polyol] Raw material polyols A-1 to A-4 shown in Table 1 below were prepared. [Table 1]

[0165] [Synthesis of raw material polyol A-5] 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-5. The number average molecular weight of the resulting raw material polyol A-5 was 2030. [Table 2]

[0166] <2-1-2. Preparing raw isocyanate> The raw material isocyanates shown in Table 3 below were prepared. [Table 3]

[0167] <2-1-3. Example of manufacturing hydroxyl group-terminated urethane prepolymer> [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]

[0168] [Synthesis of hydroxyl-terminated urethane prepolymers C-2 and C-3] Hydroxyl-terminated urethane prepolymers C-2 and C-3 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.

[0169] The chemical structures of these hydroxyl group-terminated urethane prepolymers C-1 to C-3 are as follows: 1 H-NMR and 13 The molecular weights were determined using C-NMR. In Table 5, m, n, o, p, q, r, and s in the structural formulas (1) and (3) represent the average number of moles added. [Table 5]

[0170] For the hydroxyl group-terminated urethane prepolymers C-1 to C-2 containing the structure represented by structural formula (1) in the molecule, R13 in structural formula (1) was the same as R12.

[0171] In the tables, the description "x, y = A", such as m and n = 6.9, indicates that the average number of moles added of x and y is A. The same applies to the following tables.

[0172] <2-1-4. Production example of isocyanate-terminated prepolymer> [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]

[0173] [Synthesis of isocyanate-terminated prepolymer D-2] Isocyanate-terminated prepolymer D-2 was prepared using the types and amounts of starting materials shown in Table 7 below in the same manner as in the synthesis of isocyanate-terminated prepolymer D-1.

[0174] The chemical structures of these isocyanate group-terminated prepolymers D-1 to D-9 are as follows: 1 H-NMR and 13 The molecular weights were determined using C-NMR. In Table 7, m, n, o, p, q, r, and s in the structural formulas (2) and (4) represent the average number of moles added. [Table 7]

[0175] [2-2. Preparation of resin layer additive raw materials] [Preparation of polyoxyethylene polyoxypropylene alkyl ether E-1] Additive E-1, which is a polyoxyethylene polyoxypropylene alkyl ether shown in Table 8 below, was purchased commercially.

[0176] [Table 8]

[0177] [2-3. Preparation of roughening particles] H-1, which is urethane particles used as roughening particles, shown in Table 9 below, is a commercially available product. [Table 9]

[0178] [2-4. Example of manufacturing coating liquid for forming resin layer] <2-4-1. Preparation of Coating Solution F-1 for Forming Resin Layer> The materials for resin 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% by mass, and the mixture was mixed using a sand mill. Next, 2-butanone (MEK) was added to adjust the viscosity of the solution to within the range of 6 to 10 mPa·s, producing resin layer-forming coating solution F-1.

[0179] [Table 10]

[0180] <2-4-2. Preparation of Coating Solutions F-2 and F-3 for Forming Resin Layer> Resin layer-forming coating solutions F-2 and F-3 were prepared as follows: First, the hydroxyl-terminated urethane prepolymer, isocyanate-terminated prepolymer, additives, 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 resin layer-forming coating solutions F-2 and F-3. [Table 11]

[0181] [2-5. Manufacturing of developing rollers] In this embodiment, a developing roller in which a resin layer is coated on an elastic roller having an elastic layer on the outer surface of a base body will be described, but the invention is not limited to this configuration.

[0182] <2-5-1. Adjustment of the base> 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.

[0183] <2-5-2. Preparation of Elastic Layer> The substrate was placed in a mold, and an addition-type silicone rubber composition prepared by mixing the materials shown in Table 12 was poured into the cavity formed in the mold. [Table 12]

[0184] 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.

[0185] <2-5-3. Preparation of resin layer> The elastic roller was oriented with its longitudinal direction in the vertical direction, and its upper end was gripped and immersed (dipped) in the resin layer-forming coating 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 for 1 hour in a hot air circulating dryer set at 160°C. In this way, a developing roller G-1 was obtained, in which a resin layer with a thickness of 12 μm was formed on the elastic layer.

[0186] <2-5-4. Details of measuring method for developing roller characteristics> (impedance measurement) Impedance measurements were performed as follows. First, as a pretreatment, a measurement electrode was prepared by vacuum-evaporating platinum onto the developing roller G-1 while it was rotating. Vacuum evaporation was performed using a vacuum evaporation device with a mechanism for gripping the base of the roller (the object to be coated) and rotating it circumferentially. The roller rotation speed, evaporation distance, and evaporation time were controlled to achieve a film thickness of 100 nm or more. A 1.5 cm wide electrode was then prepared using masking tape. By forming the electrode with a film thickness of 100 nm or more, the contribution of the contact area between the measuring electrode and the developing roller, which is caused by the surface roughness of the developing roller, can be minimized.

[0187] Next, an aluminum sheet was wrapped tightly around the electrode, and the aluminum sheet was connected to the measurement electrodes of an impedance measuring device (product names: Solartron 1260 and Solartron 1296, manufactured by Solartron Corporation) and a high-voltage system (product names: 6792 and HVA-500, manufactured by Toyo Corporation).

[0188] Figure 5 shows a schematic diagram of the state in which the measurement electrodes are formed on the developing roller. In Figure 5, 51 is a conductive substrate, 52 is a resin layer, 53 is a platinum vapor deposition layer, and 54 is an aluminum sheet. In this figure, the elastic layer is not shown, but it exists between the substrate 51 and the resin layer 52.

[0189] Figure 6 shows a cross-sectional view of the developing roller with the measurement electrodes formed on it. 61 is the conductive substrate, 62 is the elastic layer, 63 is the resin layer, 64 is the platinum vapor deposition layer, and 65 is the aluminum sheet. It is important that the resin layer is sandwiched between the conductive substrate and the measurement electrode.

[0190] Figure 7 shows a schematic diagram of this measurement system. The aluminum sheet was connected to the measurement electrodes of an impedance measurement device (S1: (Solatron 1260, Solartron Corporation) and S2: (Solatron 1296, Solartron Corporation)) and a high-voltage system (H1: (product name: 6792, Toyo Corporation) and H2: (product name: HVA-500, Toyo Corporation), and H3: (reference box 6796, Solartron Corporation)). Impedance measurements were performed using the conductive substrate and the aluminum sheet as the two electrodes for measurement.

[0191] The impedance was measured at a temperature of 23°C and a relative humidity of 50%, with a DC voltage of 50V and an AC voltage of 50V applied, and a frequency of 1.0 x 10 -1 ~1.0×10 5 The absolute value of the impedance was obtained at frequencies of 1.0×100 to 1.0×101 Hz. The minimum impedance value was then confirmed at frequencies of 1.0×100 to 1.0×101 Hz. The impedance was measured at the center of the developing roller in the longitudinal direction.

[0192] (Measurement of surface potential) The surface potential of the developing roller was measured using a charge amount measuring device (product name: DRA-2000L, manufactured by QEA) shown in Figure 8. Specifically, in an environment of 23°C temperature and 50% relative humidity, the grid part of the corona discharger of the charge amount measuring device was positioned so that the gap between it and the outer surface of the developing roller was 1 mm. The grid part of the corona discharger of the above device was 3.0 mm wide.

[0193] Next, a voltage of 8 kV was applied to the corona charger, and the corona charger was moved relatively along the axial direction of the developing roller at a speed of 400 mm / sec to charge the surface of the conductive member, and the potential of the outer surface was measured 0.06 sec after the grid had passed. The maximum value of all measurements taken at eight locations in the longitudinal direction at 45° intervals around the circumference of the developing roller was used.

[0194] 3. Toner In this embodiment, toner having a particle size of 7 μm and a normal negative charge polarity is used. The toner of this embodiment is, for example, a polymerized toner produced by a polymerization method. The toner of this embodiment is a so-called non-magnetic one-component developer that does not contain a magnetic component. A non-magnetic one-component developer is carried on a developing roller mainly by intermolecular forces and electrostatic forces (image forces). In addition to toner particles, one-component developers may also contain additives (such as wax or inorganic fine particles) to adjust the fluidity and charging performance of the toner. The additive is sometimes called an external additive. In the present invention, the surface of the toner particle has a conductivity of 1×10 -15 Surface particles or organosilicon polymers of S / m or more, The toner used has a surface particle coverage of 35% or more and a surface particle adhesion rate of 80% or more. The conductivity of the surface particles or organosilicon polymer is preferably 1.0×10 2 S / m or less is preferable. 2If it is larger than S / m, the charge is easily discharged, and sufficient injection chargeability may not be obtained.

[0195] The methods for measuring the conductivity, coverage, and adhesion rate will be described later.

[0196] In addition, the surface of the toner particles has a conductivity of 1×10 -15 S / m or more As a means of coating the surface particles or organosilicon polymers, conductivity is 1×10 -15 S The adhesion rate can be controlled by the order of adding the materials, the temperature during addition, the rotation speed, etc.

[0197] Conductivity is 1 x 10 -15 As an external additive of S / m or more, antimony-tin oxide-titanium Antimony-based oxides, antimony-titanium-based oxides, antimony-tin-based oxides, indium-tin Indium-titanium oxide, niobium-tin oxide, niobium-titanium oxide , zinc oxide, etc., but are not limited to these.

[0198] Next, the organosilicon polymer will be described.

[0199] <Surface layer containing organosilicon polymer> When the toner particles have a surface layer containing an organosilicon polymer, it is preferred that the surface layer have a partial structure represented by formula (1). R-SiO3 / 2 formula (1) (R represents a hydrocarbon group having 1 to 6 carbon atoms.)

[0200] In organosilicon polymers with the structure of formula (1), one of the four valences of the Si atom is bonded to R, and the remaining three are bonded to O atoms. The O atom has two valences bonded to Si, forming a siloxane bond (Si-O-Si). When considering the Si and O atoms as an organosilicon polymer, two Si atoms have three O atoms, so it is expressed as -SiO3 / 2.

[0201] A preferred example of the production of organosilicon polymers is the sol-gel process. The sol-gel process uses liquid starting materials as starting materials, undergoes hydrolysis and condensation polymerization, and then gels after passing through a sol state. This process is used to synthesize glass, ceramics, organic-inorganic hybrids, and nanocomposites. This production method allows functional materials in various shapes, such as surface layers, fibers, bulk materials, and microparticles, to be produced from the liquid phase at low temperatures.

[0202] Specifically, the organosilicon polymer present on the surface layer of the toner particles is preferably produced by hydrolysis and condensation polymerization of a silicon compound, typically an alkoxysilane.

[0203] Furthermore, the sol-gel method allows for the creation of a variety of microstructures and shapes because it starts with a liquid and forms a material by gelling the liquid. In particular, when toner particles are produced in an aqueous medium, the hydrophilic properties of the organosilicon compound, such as the silanol groups, facilitate precipitation on the surface of the toner particles. The microstructure and shape can be adjusted by adjusting the reaction temperature, reaction time, reaction solvent, pH, and the type and amount of organometallic compound.

[0204] The organosilicon polymer in the surface layer of the toner particles is preferably a condensation polymer of an organosilicon compound having a structure represented by the following formula (Z). [ka] In formula (Z), R1 represents a hydrocarbon group having 1 to 6 carbon atoms, and R2, R3, and R4 each independently represent a halogen atom, a hydroxy group, an acetoxy group, or an alkoxy group. represent.

[0205] The hydrocarbon group (preferably an alkyl group) of R1 can improve hydrophobicity, resulting in toner particles with excellent environmental stability. Furthermore, an aryl group, which is an aromatic hydrocarbon group, such as a phenyl group, can also be used as the hydrocarbon group. When R1 is highly hydrophobic, the charge amount tends to fluctuate significantly in various environments. Therefore, in consideration of environmental stability, R1 is preferably a hydrocarbon group having 1 to 3 carbon atoms, and more preferably a methyl group.

[0206] R2, R3, and R4 are each independently a halogen atom, a hydroxy group, an acetoxy group, or an alkoxy group (hereinafter also referred to as a reactive group). These reactive groups undergo hydrolysis, addition polymerization, and condensation polymerization to form a crosslinked structure, thereby producing a toner with excellent resistance to component contamination and development durability. From the viewpoints of mild hydrolysis at room temperature and deposition and coating properties on the surface of toner particles, an alkoxy group having 1 to 3 carbon atoms is preferred, and a methoxy group or an ethoxy group is more preferred. Furthermore, the hydrolysis, addition polymerization, and condensation polymerization of R2, R3, and R4 can be controlled by the reaction temperature, reaction time, reaction solvent, and pH.

[0207] To obtain the organosilicon polymer used in this invention, it is advisable to use one or a combination of several organosilicon compounds (hereinafter also referred to as trifunctional silanes) having three reactive groups (R2, R3, and R4) in one molecule excluding R1 in the formula (Z) shown above. Furthermore, the content of the organosilicon polymer in the toner particles is preferably 0.5% by weight or more and 10.5% by weight or less.

[0208] By having an organosilicon polymer content of 0.5% by mass or more, the surface free energy of the surface layer can be further reduced, fluidity can be improved, and the occurrence of component contamination and fogging can be further suppressed. By having an organosilicon polymer content of 10.5% by mass or less, charge-up can be made less likely to occur. The organosilicon polymer content can be controlled by the type and amount of organosilicon compound used to form the organosilicon polymer, the method for producing the toner particles when forming the organosilicon polymer, the reaction temperature, reaction time, reaction solvent, and pH.

[0209] It is preferable that the surface layer containing the organosilicon polymer and the toner core particle are in contact with each other without any gaps, which suppresses bleeding of resin components and release agents inside the toner particle rather than the surface layer, thereby obtaining a toner with excellent storage stability, environmental stability, and development durability.

[0210] [3-1. Manufacturing method of toner particles] Toner particles can be produced by known methods, such as a kneading and pulverization method or a wet production method. From the viewpoint of uniform particle size and shape controllability, a wet production method is preferably used. Further, examples of the wet production method include a suspension polymerization method, a solution suspension method, an emulsion polymerization aggregation method, and an emulsion aggregation method.

[0211] Here, the suspension polymerization method will be described. In the suspension polymerization method, first, a polymerizable monomer composition is prepared by uniformly dissolving or dispersing a polymerizable monomer for producing a binder resin, a colorant, and other additives as needed using a disperser such as a ball mill or an ultrasonic disperser (polymerizable monomer composition preparation step).

[0212] At this time, polyfunctional monomers, chain transfer agents, wax as a release agent, charge control agents, plasticizers, etc. may be added as needed.

[0213] Next, the polymerizable monomer composition is poured into a previously prepared aqueous medium, and a high shear force is applied to the mixture. Using a stirrer or disperser having a diameter of 100 mm or less, droplets of the polymerizable monomer composition are formed into toner particles of a desired size (granulation step).

[0214] It is preferable that the aqueous medium used in the granulation process contains a dispersion stabilizer in order to control the particle size of the toner particles, sharpen the particle size distribution, and prevent the coalescence of toner particles during the manufacturing process. Dispersion stabilizers are generally broadly classified into polymers that exhibit repulsive forces due to steric hindrance and poorly water-soluble inorganic compounds that stabilize dispersion by electrostatic repulsive forces. Fine particles of poorly water-soluble inorganic compounds are preferably used because they dissolve in acid or alkali and can be easily removed by washing with acid or alkali after polymerization.

[0215] After the granulation step, or while the granulation step is being carried out, the temperature is preferably set to 50°C or higher and 90°C or lower to polymerize the polymerizable monomers contained in the polymerizable monomer composition, thereby obtaining a toner particle dispersion (polymerization step).

[0216] In the polymerization step, stirring is preferably performed so as to achieve a uniform temperature distribution in the vessel. When adding a polymerization initiator, this can be done at any timing and for any required time. The temperature may be raised in the latter half of the polymerization reaction to obtain a desired molecular weight distribution. Furthermore, in order to remove unreacted polymerizable monomers, by-products, etc. from the system, a portion of the aqueous medium may be distilled off in the latter half of the reaction or after completion of the reaction. The distillation can be performed under normal pressure or reduced pressure.

[0217] The weight average particle size of the toner particles is preferably 3.0 μm or more and 10.0 μm or less from the viewpoint of obtaining high-definition, high-resolution images. The weight average particle size of the toner can be measured by the pore electrical resistance method. For example, it can be measured using a Coulter Counter Multisizer 3 (manufactured by Beckman Coulter, Inc.). The toner particle dispersion thus obtained is sent to a filtration process for solid-liquid separation of the toner particles and the aqueous medium.

[0218] Solid-liquid separation to obtain toner particles from the resulting toner particle dispersion can be performed by a general filtration method, and then, in order to remove any foreign matter that has not been completely removed from the toner particle surface, further washing is preferably performed by reslurrying or washing with washing water. After sufficient washing, solid-liquid separation is again performed to obtain a toner cake. Thereafter, the toner cake is dried by a known drying means, and if necessary, particle groups having particle sizes other than the specified particle size are separated by classification to obtain toner particles. The particle groups having particle sizes other than the specified particle size separated at this time may be reused to improve the final yield.

[0219] When forming a surface layer containing an organosilicon polymer, if toner particles are formed in an aqueous medium, the surface layer can be formed by adding a hydrolyzed solution of an organosilicon compound as described above while performing a polymerization process in the aqueous medium.The dispersion of toner particles after polymerization can be used as a core particle dispersion, and the hydrolyzed solution of an organosilicon compound can be added to form the surface layer.In addition, when a medium other than an aqueous medium is used, such as a kneading and grinding method, the obtained toner particles can be dispersed in an aqueous medium and used as a core particle dispersion, and the hydrolyzed solution of an organosilicon compound can be added as described above to form the surface layer.

[0220] [3-2. Methods for measuring various characteristics of toner particles] <Method for measuring adhesion rate of surface particles (external additives) or organosilicon polymers> Add 160 g of sucrose (Kishida Chemical) to 100 mL of ion-exchanged water and dissolve in a hot water bath to prepare a concentrated sucrose solution. 31 g of the above concentrated sucrose solution and 6 mL 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, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) are placed in a centrifuge tube (50 mL capacity) to prepare a dispersion. Add 1.0 g of toner to this dispersion and stir. Use a vacuum cleaner or similar to break up the toner clumps.

[0221] The centrifuge tube is shaken in a shaker at 350 strokes per minute (spm) for 20 minutes. After shaking, the solution is transferred to a glass tube for a swing-out rotor (50 mL capacity) and separated in a centrifuge (H-9R, manufactured by Kokusan Co., Ltd.) at 3500 rpm for 30 minutes. Visually confirm that the toner and aqueous solution are sufficiently separated, and collect the toner that has separated to the top layer with a spatula. The collected aqueous solution containing the toner is filtered through a vacuum filter and then dried in a dryer for at least 1 hour. The dried product is crushed with a spatula, and the adhesion rate (%) is calculated using fluorescent X-rays. Fluorescent X-ray measurements of each element are in accordance with JIS K 0119-1969, specifically as follows:

[0222] The measurement equipment used was a wavelength dispersive X-ray fluorescence analyzer "Axios" (PANalytical) and the accompanying dedicated software "SuperQ ver.4.0F" (PANalytical) for setting measurement conditions and analyzing measurement data. Rh was used as the anode of the X-ray tube, the measurement atmosphere was vacuum, the measurement diameter (collimator mask diameter) was 10 mm, and the measurement time was 10 seconds. Light elements were detected using a proportional counter (PC), and heavy elements were detected using a scintillation counter (SC).

[0223] The measurement sample was prepared by placing approximately 1 g of the washed toner and the initial toner in a special aluminum ring for pressing, 10 mm in diameter, and flattening it. The ring was then pressed at 20 MPa for 60 seconds using a tablet molding compressor "BRE-32" (manufactured by Maekawa Testing Machinery Manufacturing Co., Ltd.) to form a pellet approximately 2 mm thick.

[0224] Fluorescent X-ray analysis was performed under the above conditions, and the adhesion rate of external additives or organosilicon polymers was calculated as follows: It was calculated using the formula:

[0225] Adhesion rate (%) of surface particles (external additives) or organosilicon polymers = (strength of elements derived from external additives or organosilicon polymers in treated toner / strength of elements derived from external additives or organosilicon polymers in untreated toner) x 100

[0226] <Method for calculating the surface coverage of toner particles> (Method for obtaining a backscattered electron image of the surface of toner particles) The coverage of the toner particle surface with the external additive or organosilicon polymer is calculated using a backscattered electron image of the toner particle surface.

[0227] A backscattered electron image of the surface of a toner particle is obtained using a scanning electron microscope (SEM). The backscattered electron image obtained from an SEM is also called a "composition image," and particles with smaller atomic numbers are detected as darker, and particles with larger atomic numbers are detected as brighter.

[0228] Toner particles are generally resin particles that primarily contain carbon-based compositions such as resin components and release agents. When external additives or organosilicon polymers are present on the surface of toner particles, the external additives or organosilicon polymers are observed as bright areas and the toner core particle surfaces as dark areas in backscattered electron images obtained from SEM.

[0229] The SEM equipment and observation conditions are as follows: Equipment used: ULTRAPLUS manufactured by Carl Zeiss Microscopy Co., Ltd. Acceleration voltage: 1.0 kV WD: 2.0mm Aperture Size: 30.0 μm Detection signal: EsB (energy selective backscattered electrons) EsBGrid:800V Magnification: 50,000x Contrast: 63.0±5.0% (reference value) Brightness: 38.0±5.0% (reference value) Image size: 1024 x 768 pixels Pre-treatment: Toner particles are scattered on carbon tape (no deposition is performed)

[0230] Contrast and brightness are set appropriately according to the state of the equipment being used. The accelerating voltage and EsBGrid are set to achieve the following: obtaining structural information on the outermost surface of the toner particles, preventing charging up of undeposited samples, and selectively detecting high-energy reflected electrons. The observation field is selected to be near the vertex where the curvature of the toner particles is smallest.

[0231] (Method to confirm that bright areas in backscattered electron images are derived from external additives or organosilicon polymers) The fact that the bright areas in the observed backscattered electron image are derived from external additives or organosilicon polymers can be confirmed by overlaying the backscattered electron image with an elemental mapping image obtained by energy dispersive X-ray analysis (EDS) using a scanning electron microscope (SEM).

[0232] The SEM / EDS equipment and observation conditions are as follows: Equipment used (SEM): ULTRAPLUS manufactured by Carl Zeiss Microscopy Co., Ltd. Equipment used (EDS): NORAN System 7, Ultra Dry EDS Detector manufactured by Thermo Fisher Scientific Co., Ltd. Acceleration voltage: 5.0 kV WD:7.0mm Aperture Size: 30.0 μm Detection signal: SE2 (secondary electrons) Magnification: 50,000x Mode: Spectral Imaging Pre-treatment: Toner particles are scattered on carbon tape and then platinum sputtered.

[0233] The mapping image of inorganic elements derived from external additives or organosilicon polymers obtained using this method is superimposed on the backscattered electron image, and it is confirmed that the inorganic atomic portions in the mapping image match the bright areas in the backscattered electron image. The areas where both the inorganic atomic portions and the carbon atom portions in the mapping image match the bright areas in the backscattered electron image are identified as external additives or organosilicon polymers.

[0234] The organosilicon polymer and silica can be distinguished by confirming that the portion containing both silicon atoms and carbon atoms is the organosilicon polymer.

[0235] (Method for calculating the coverage of toner particle surfaces by surface particles (external additives) or organosilicon polymers) The coverage is calculated based on the uncoated domain D1, which is not coated with external additives or organosilicon polymers, and the coated domain D2, which is coated with external additives or organosilicon polymers. Domains D1 and D2 are analyzed using the backscattered electron image of the outermost surface of the toner particles obtained by the above method, using the image processing software ImageJ (developed by Wayne Rashand). The procedure is as follows:

[0236] First, convert the backscattered electron image to be analyzed to 8-bit using Type in the Image menu. Next, set the median diameter to 2.0 pixels using Filters in the Process menu to reduce image noise. The observation condition table is displayed below the backscattered electron image. After excluding the displayed area, estimate the center of the image and use the Rectangle tool ( Using the tool, select a 1.5 μm square area from the center of the backscattered electron image.

[0237] Next, use the Freehand selections function in the Image menu to select only the areas where the carbon atom parts of the mapping image match the dark areas of the backscattered electron image, and paint them all black. Also, paint everything except the areas where the carbon atom parts of the mapping image match the dark areas of the backscattered electron image with white. Next, select Threshold from Adjust. Manually, select 128 as the threshold, which is the middle gradation between black and white in an 8-bit image, and click Apply to obtain a binarized image. This operation displays pixels corresponding to the uncoated domain D1 (toner core particles) in black (pixel group A1), and pixels corresponding to the coated domain D2 (external additive or organosilicon polymer) in white (pixel group A2).

[0238] Again, estimate the center of the image after excluding the observation condition display area at the bottom of the backscattered electron image, and use the Rectangle Tool on the toolbar to select a 1.5 μm square area from the center of the backscattered electron image.

[0239] Next, use the straight line tool (Straight Line) on the toolbar to select the scale bar in the observation condition display area below the backscattered electron image. In this state, select Set Scale from the Analyze menu. A new window will open and the pixel distance of the selected straight line will be entered in the Distance in Pixels field.

[0240] Enter the value of the scale bar (for example, 100) in the Known Distance field of the window, enter the unit of the scale bar (for example, nm) in the Unit of Measurement field, and click OK to complete the scale setting.

[0241] Next, select "Set Measurements" from the Analyze menu, check "Area" and "Feret's diameter", select "Analyze Particles" from the Analyze menu, check "Display Result", and click "OK" to perform domain analysis.

[0242] From the newly opened Results window, the area (Area) of each domain corresponding to the uncovered portion domain D1 formed by the pixel group A1 and the covered portion domain D2 formed by the pixel group A2 is obtained.

[0243] The obtained total area of ​​the non-coated domains D1 is S1 (μm2), and the obtained total area of ​​the coated domains D2 is S2 (μm2). The coverage rate S is calculated from the obtained S1 and S2 using the following formula. S(area%)={S2 / (S1+S2)}×100

[0244] The above procedure is carried out for 10 visual fields for the toner particles to be evaluated, and the arithmetic mean value is used as the coverage ratio.

[0245] <Method for measuring the conductivity of surface particles (external additives) or organosilicon polymers> Add 160 g of sucrose (Kishida Chemical) to 100 mL of ion-exchanged water and dissolve in a hot water bath to prepare a concentrated sucrose solution. Place 31 g of the above concentrated sucrose solution and 6 mL 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, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) in a 50 mL centrifuge tube to prepare a dispersion. Add 1.0 g of toner to this dispersion and break up any clumps of toner with a spatula or similar.

[0246] The centrifugation tube is shaken in a shaker (MIGHTYSHAKERAS-1N, AS ONE Corporation) at 300 rpm and a shaking amplitude of 40 mm for 20 minutes.

[0247] After shaking, the solution is transferred to a swing rotor glass tube (50 mL capacity) and separated in a centrifuge (H-9R, manufactured by Kokusan Co., Ltd.) at 3500 rpm for 30 minutes. Visually confirm that the toner and aqueous solution are sufficiently separated, and collect the toner that has separated to the top layer with a spatula. After washing the collected sample with water, the resin component of the toner core particles in the sample is burned under air to collect surface particles (external additives) or organosilicon polymers (hereinafter referred to as "powder"). The volume resistivity of the collected material is measured as follows.

[0248] The capacitance and conductivity of the air and powder are measured by impedance measurement using the parallel plate capacitor method (Figure 10).

[0249] The equipment used is a measurement jig consisting of a four-terminal sample holder SH2-Z (manufactured by Toyo Corporation) (T1) and a torque wrench adapter SH-TRQ-AD (optional) (not shown), and a materials testing system ModuLab XM MTS (manufactured by Solartron) (T2). Also used is a noise-cutting transformer NCT-I3 1.4kVA (manufactured by Denken Seiki Kenkyusho Co., Ltd.) (not shown) to suppress commercial power supply noise, and a shielding box (T3) to suppress electromagnetic noise.

[0250] The measurement jig uses a four-terminal sample holder T3 and the optional torque wrench adapter SH-TRQ-AD (not shown), and uses the upper electrode (Φ25mm solid electrode) SH-H25AU (T4) and the lower electrode for liquids / powder (center electrode Φ10mm; guard electrode Φ26mm) SH-2610AU (T5) as parallel plate electrodes, with a configuration capable of measuring resistances of 0.1Ω to 1TΩ for electrical signals of up to 500Vp-p and DC to 1MHz (Figure 10).

[0251] To adjust the sample pressure, 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 T1. The torque driver used to control the pressure was the torque driver RTD30CN (manufactured by Tohnichi Manufacturing Co., Ltd.) with a 6.35 mm square bit, configured to be able to control the tightening torque to 20.0 cN m.

[0252] The electrical AC characteristics were measured using the ModuLab XM MTS (Solartron) T2 material testing system, which measures impedance. The ModuLab XM MTS (T2) is equipped with a control module XM MAT 1MHz, a high-voltage module XM MHV100, a femtocurrent module XM MFA, and a frequency response analysis module XM MRA. The control software is the company's XM-studio MTS Ver. 3.4. The measurement conditions are Normal Mode, which only performs measurements, 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).

[0253] 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

[0254] Under the above measurement conditions, the impedance characteristics, which are the electrical AC characteristics of powder T6, were measured. implement.

[0255] 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 air and powder T6 can be obtained at a film thickness d corresponding to a 10mm diameter measurement electrode S and pressure torque. From the obtained impedance characteristics of air and powder T6, 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 toner measurement jig (parallel plate electrode size S and sample film thickness), the electrical properties of relative permittivity and conductivity can be calculated.

[0256] When using the four-terminal sample holder SH2-Z(T1) for the first time, two verifications must be carried out to find the optimal measurement conditions, since there are individual differences in the four-terminal sample holder SH2-Z(T1) used in the powder measurement jig.

[0257] The first verification is the film thickness dependency characteristics of the four-terminal sample holder (T1). 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.

[0258] The second verification is the measurement of mechanical error. When measuring the sample, 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.

[0259] The specific sample preparation and measurement procedures are as follows. (1) Powder T6 is piled on the central electrode portion of the lower electrode and formed into a trapezoidal shape with a height of 5 mm. (2) The lower electrode with the powder T6 piled on it is attached to the four-terminal sample holder SH2-Z(T1), and the upper electrode is lowered. (3) At this time, the upper electrode T4 is lowered to the upper end of the powder while keeping it constant so as not to rotate unintentionally. (4) While rotating the upper electrode T4 left and right, smoothing treatment is performed so that the powder T6 becomes smooth. (5) Using a micrometer, adjust the film thickness to a predetermined value while keeping the rotation direction of the upper electrode T4 constant. (6) Apply pressure using a torque driver that is sized to fit powder T6. (7) Measure the sample film thickness using a micrometer. (8) Impedance measurement is carried out under the above conditions.

[0260] (9) After the measurement is completed, the upper electrode T4 is raised and the lower electrode T5 is removed. At this time, the lower electrode is removed carefully so that the powder T6 does not get into the contact terminal for the lower electrode of the four-terminal sample holder T1, and the lower electrode is protected with masking tape. (10) Clean the upper and lower electrodes. (11) Remove the masking tape and attach the lower electrode T5. (12) The sample film thickness d obtained in step (7) is adjusted to the air thickness t, taking into account the 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 process Start the process again from step (10) of the cleaning process.

[0261] 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 characteristic that has 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 in this invention is the value at a frequency of 0.01 Hz.

[0262] The toners produced are shown below.

[0263] [3-3. Toner manufacturing example] <Toner 1> (Preparation step of aqueous medium 1) To 1000.0 parts of ion-exchanged water in a reaction vessel, 14.0 parts of sodium phosphate (Rasa Kogyo Co., Ltd., dodecahydrate) was added, and the mixture was kept at 65°C for 1.0 hour while being purged with nitrogen.

[0264] Aqueous medium containing a dispersion stabilizer was prepared by adding an aqueous calcium chloride solution prepared by dissolving 9.2 parts of calcium chloride (dihydrate) in 10.0 parts of ion-exchanged water all at once while stirring at 12,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) Further, 10% by mass of hydrochloric acid was added to the aqueous medium to adjust the pH to 5.0, thereby obtaining aqueous medium 1.

[0265] (Hydrolysis process of organic silicon compounds for surface layer) 60.0 parts of ion-exchanged water was weighed into a reaction vessel equipped with a stirrer and a thermometer, and the pH was adjusted to 3.0 using 10% by mass of hydrochloric acid. This was heated with stirring until the temperature reached 70°C. 40.0 parts of methyltriethoxysilane, an organosilicon compound for the surface layer, was then added and stirred for 2 hours or more to carry out hydrolysis. The end point of the hydrolysis was confirmed by visual inspection when the oil and water were not separated and a single layer was formed, and the mixture was cooled to obtain a hydrolyzed solution of the organosilicon compound for the surface layer.

[0266] (Preparation step of polymerizable monomer composition) Styrene: 60.0 parts Carbon black (Nipex 35): 6.0 parts

[0267] The materials were placed in an attritor (manufactured by Mitsui Miike Chemical Engineering Co., Ltd.), and further dispersed using zirconia particles with a diameter of 1.7 mm at 220 rpm for 5.0 hours to prepare a pigment dispersion. The following materials were added to the pigment dispersion. Styrene: 20.0 parts n-Butyl acrylate: 20.0 parts Crosslinking agent (divinylbenzene): 0.3 parts Saturated polyester resin: 5.0 parts (Polycondensation of propylene oxide modified bisphenol A (2 mole adduct) and terephthalic acid (molar ratio 10:12, glass transition temperature Tg = 68°C, weight average molecular weight Mw = 10,000, molecular weight distribution Mw / Mn = 5.12) Fischer-Tropsch wax (melting point 78°C): 7.0 parts

[0268] The mixture was kept at 65°C and uniformly dissolved and dispersed at 500 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to prepare a polymerizable monomer composition.

[0269] (granulation process) While maintaining the temperature of the aqueous medium 1 at 70°C and the rotation speed of the TK homomixer at 12,000 rpm, the polymerizable monomer composition was charged into the aqueous medium 1, and 9.0 parts of t-butyl peroxypivalate as a polymerization initiator was added. Granulation was continued for 10 minutes while maintaining the stirring speed at 12,000 rpm with the stirring device.

[0270] (Polymerization process) After the granulation process, the agitator was replaced with a propeller agitator and stirred at 150 rpm. Polymerization was carried out at 70°C for 5.0 hours, then the temperature was raised to 85°C and heated for 2.0 hours to complete the polymerization reaction and obtain core particles. The slurry was cooled to 55°C and the pH was measured, which was 5.0. While continuing to stir at 55°C, 15.0 parts of a hydrolyzed solution of an organosilicon compound for the surface layer was added to initiate the formation of the toner surface layer. After holding for 30 minutes, the slurry was adjusted to pH 9.0 using aqueous sodium hydroxide to complete the condensation, and then held for an additional 300 minutes to form the surface layer.

[0271] (Washing and drying process) After the polymerization process was completed, the toner particle slurry was cooled, and hydrochloric acid was added to the toner particle slurry to adjust the pH to 1.5 or less. The mixture was then stirred for 1 hour and then subjected to solid-liquid separation using a pressure filter to obtain a toner cake. This was then reslurried with ion-exchanged water to form a dispersion again, and then subjected to solid-liquid separation using the aforementioned filter. The reslurrying and solid-liquid separation were repeated until the electrical conductivity of the filtrate reached 5.0 μS / cm or less, after which solid-liquid separation was finally performed to obtain a toner cake.

[0272] The obtained toner cake was dried in a flash jet dryer (manufactured by Seishin Enterprises), and further fine and coarse particles were removed using a multi-division classifier utilizing the Coanda effect to obtain toner particles 1. The drying conditions were an inlet temperature of 90°C, a dryer outlet temperature of 40°C, and the toner cake supply rate was adjusted according to the moisture content of the toner cake so that the outlet temperature did not deviate from 40°C. In this production example, the obtained toner particles 1 were used as toner 1 as is without any external additions.

[0273] The evaluation method for Toner 1 is described below. -Method for measuring adhesion rate Measurements were carried out using the method described in <Method for measuring adhesion rate of surface particles (external additives) or organosilicon polymers>. The evaluation results are shown in Tables 14-3 and 14-4.

[0274] -Method for measuring coverage Measurement was carried out by the method described in <Method for measuring the surface coverage of toner particles>. The evaluation results are shown in Tables 14-3 and 14-4.

[0275] Conductivity measurement method Measurements were carried out using the method described in <Method for measuring the conductivity of surface particles (external additives) or organosilicon polymers>. The evaluation results are shown in Tables 14-3 and 14-4.

[0276] Toner irregularity evaluation The irregularity of the toner was evaluated based on the aspect ratio of the toner. The aspect ratio was measured using a flow particle image analyzer, "FPIA-3000" (manufactured by Sysmex Corporation). The measurement was performed under the same measurement and analysis conditions as during the calibration work.

[0277] To 20 mL of ion-exchanged water, an appropriate amount of surfactant, alkylbenzene sulfonate, was added as a dispersant, and then 0.02 g of the measurement sample was added. The mixture was dispersed for 2 minutes using a tabletop ultrasonic cleaner disperser (product name: VS-150, manufactured by Vervoclear Co., Ltd.) with an oscillation frequency of 50 kHz and an electrical output of 150 watts to obtain a dispersion for measurement. The dispersion was then cooled appropriately so that its temperature was between 10°C and 40°C.

[0278] For the measurement, the flow-type particle image analyzer equipped with a standard objective lens (10x) was used, and the particle sheath "PSE-900A" (manufactured by Sysmex Corporation) was used as the sheath liquid. The dispersion prepared according to the above procedure was introduced into the flow-type particle image analyzer, and 3,000 toner particles (particles) were measured in HPF measurement mode and total count mode. The binarization threshold for particle analysis was set to 85%, and the analyzed particle diameter was limited to a circular equivalent diameter of 1.98 μm to 19.92 μm, and the toner aspect ratio was determined.

[0279] Before starting the measurement, automatic focus adjustment is performed using standard latex particles (for example, 5100A (trade name) manufactured by Duke Scientific diluted with ion-exchanged water). After that, it is preferable to perform focus adjustment every two hours from the start of the measurement. [Table 13-1]

[0280] [Table 13-2]

[0281] <Toner 2, Toner 3> Except for changing the number of parts of hydrolysis liquid added in the polymerization step as shown in Tables 13-1 and 13-2, toners were produced in the same manner as toner 1. The measurement results of toners 2 and 3 obtained are shown in Tables 13-1 and 13-2.

[0282] <Toner 4> Toner particles were prepared in the same manner as Toner 1, except that the hydrolyzed liquid of the surface layer organosilicon compound was not added in the polymerization step. Titanium oxide (average particle size: 30 nm) was externally added to adhere to the toner particles, producing Toner 4. The external addition was carried out by adding the external additives in the amounts shown in Table 2 to 100 parts of toner particles into a SUPERMIXER PICCOLO SMP-2 (manufactured by Kawata Corporation) and mixing at 3,000 rpm for 10 minutes. The measurement results of the obtained toner are shown in Tables 13-1 and 13-2.

[0283] <Toner 5> Toner was produced in the same manner as Toner 4, except that the type of external additive was changed as shown in Table 13. The measurement results of Toner 5 obtained are shown in Tables 13-1 and 13-2.

[0284] 4. Image evaluation and toner irregularity evaluation The developing roller G-1 was attached as the developing roller 31 of the process cartridge 20, and the cartridge was inserted into an image forming apparatus, and image evaluation was performed. The lifespan of the process cartridge 20, including the toner capacity, was set to 5,500 sheets of A4 paper at a 5% print rate.

[0285] [4-1. Kurogo Kaburi] The prepared process cartridge was mounted in the main body of an image forming apparatus and left in an environment of a temperature of 30°C and a relative humidity of 80% for 24 hours. After that, an external high voltage power supply was used to set the potential difference of the developing blade with respect to the developing roller to -150V, and in the same environment, an A4 evaluation paper (GF- On a printer (C081, manufactured by Canon Inc.), a 4-point size "E" letter was printed on 8,000 sheets in succession, with a print coverage rate of 2% of the paper area. The printing speed was set to 150 mm / sec in the normal mode. After printing 8,000 sheets, a white image was output immediately after the black image was output without changing the potential difference of the developing blade with respect to the developing roller or the process speed.

[0286] Using a reflection densitometer (product name: TC-6DS / A, manufactured by Tokyo Denshoku Technology Center Co., Ltd.), the reflection density R1 of the recording material before image formation and the reflection density R2 of the recording material on which a white image was printed immediately after the black image were printed were measured. The increase in reflection density (R2 - R1) was taken as the "fog value" of the developing roller. The reflection density was measured over the entire image printing area of ​​the recording material, and the maximum value was used. Note that the smaller the fog value, the better; typically, toner is not transferred onto the transfer paper on which a solid white image has been formed. If the toner charge is insufficient, toner will migrate onto the photoreceptor even when forming a solid white image, and then be transferred onto the transfer paper, increasing the fog value. The evaluation results are shown in Tables 14-1 and 14-2.

[0287] The criteria for determining fogging are as follows: A: Very good level (fog less than 1.0%) B: Good level (fog 1.0% or more and less than 1.5%) C: Practically acceptable level (fog 1.5% to less than 2.5%) D: Acceptable level (fog 2.5% or more but less than 3.5%) E: Unsuitable for practical use (fog 3.5% or more)

[0288] [4-2. Inverted Coverage] The prepared process cartridge was mounted in the main body of an image forming apparatus and left in an environment of a temperature of 30°C and a relative humidity of 80% for 24 hours. After that, an external high voltage power supply was used to set the potential difference of the developing blade with respect to the developing roller to -150V, and in the same environment, an A4 evaluation paper (GF- An image of a 4-point letter "E" with a print coverage of 2% of the paper area was printed on 8,000 sheets of paper (C081, manufactured by Canon Inc.). The process speed was set to 150 mm / sec in normal mode. After printing 8,000 sheets, a white image with no image (so-called solid white) was printed without changing the potential difference between the developing blade and the developing roller or the process speed.

[0289] Using a reflection densitometer (product name: TC-6DS / A, manufactured by Tokyo Denshoku Technology Center Co., Ltd.), the reflection density R1 of the recording material before image formation and the reflection density R2 of the recording material on which a solid white image was printed were measured, and the increase in reflection density (R2 - R1) was taken as the "fog value" of the developing roller. The reflection density was measured over the entire image printing area of ​​the recording material, and the maximum value was used. The evaluation results are shown in Tables 14-1 and 14-2.

[0290] The criteria for determining fogging are as follows: A: Very good level (fog less than 1.0%) B: Good level (fog 1.0% or more and less than 1.5%) C: Practically acceptable level (fog 1.5% to less than 2.5%) D: Acceptable level (fog 2.5% or more but less than 3.5%) E: Unsuitable for practical use (fog 3.5% or more)

[0291] [4-3. Evaluation of image density stability] The prepared process cartridge was mounted in the main body of an image forming apparatus and left for 24 hours in an environment of 30°C temperature and 80% relative humidity. Then, using an external high-voltage power supply, the potential difference between the developing blade and the developing roller was set to -150V, and one solid black halftone image, 48 solid white images, and one solid black halftone image were successively output onto A4 evaluation paper (GF-C081, manufactured by Canon Inc.). The process speed was 150mm / sec in normal mode. The halftone images obtained on the first and 50th sheets were The density of the image was measured using a spectrodensitometer (product name: 508, manufactured by Xrite) to determine the difference in density between the first and 50th sheets. The smaller the density difference, the better. The evaluation results are shown in Tables 14-1 and 14-2.

[0292] The criteria for determining image density stability are as follows: 〇: Good level (less than 0.1) ×: Not good level (0.1 or more)

[0293] [4-4. Evaluation of Toner Irregularity] The prepared process cartridge was mounted in the main body of an image forming apparatus and left in an environment of a temperature of 30°C and a relative humidity of 80% for 24 hours. After that, an external high voltage power supply was used to set the potential difference of the developing blade with respect to the developing roller to -150V, and in the same environment, an A4 evaluation paper (GF- On a paper (C081, Canon Inc.), 8,000 images of a 4-point letter "E" with a print coverage of 2% of the paper area were continuously printed. The process speed was 150 mm / sec. After printing 8,000 images, the aspect ratio of the toner remaining in the developer container of the process cartridge was evaluated using the method described above. The aspect ratio of the toner after printing the image was then divided by the initial aspect ratio of the toner, and the result was multiplied by 100 to calculate the value used as the evaluation value for the degree of deformation. This value is 100% if there is no change from the initial value, and a smaller value indicates more deformation of the toner. [Table 14-1]

[0294] [Table 14-2] In the table, X is the total amount (mass %) of the compound having the structure represented by structural formula (5) based on the solid content in the coating material for forming a surface layer.

[0295] The impedance value is 1.0 x 10 0 Hz~1.0×101 This indicates the minimum impedance value in Hz. Note that notations such as "9.12E+06" represent "9.12 x 10 6 " indicates that

[0296] [Example 2] Measurements and evaluations were carried out in the same manner as in Example 1, except that the toner filled in the process cartridge 20 was changed to Toner 1. The evaluation results are shown in Tables 14-1 and 14-2.

[0297] In addition, under the same conditions as when measuring reversal fog, printing of a solid white image was forcibly stopped while it was being printed, and the toner charge amount per unit area on the developer carrier (Q / S) was determined using the following method. The evaluation results are shown in Figures 13 and 14.

[0298] <Method for measuring the amount of charge of toner per unit area on a developer carrier (Q / S)> The amount of toner carried on the developer carrier is calculated by suction-collecting the toner on the developer carrier using a metal cylindrical tube and a cylindrical filter. The amount of triboelectric charge of the toner on the developer carrier is calculated using the Faraday curve. It can be measured using a Faraday cage. A Faraday cage is a coaxial double cylinder, with the inner and outer cylinders insulated by insulating materials. If a charged body with a charge Q is placed inside this inner cylinder, electrostatic induction will create the same effect as if a metal cylinder with a charge Q were present. In practice, a suction nozzle is placed on the developer carrier, and the toner carried between the contact area with the developing blade and the contact area with the photosensitive drum is sucked in by a suction device. The sucked in toner is collected by a cylindrical filter paper (cylindrical filter) placed inside the inner cylinder. The amount of induced charge is measured with an electrometer (Kesley 6517A, manufactured by Kesley), and the amount of charge Q (nC) is divided by the sucked area S (cm2) to determine the toner charge per unit area. Let's say. Toner charge per unit area (nC / cm2) = Q / S

[0299] [Example 3] Developing roller G-2 was produced in the same manner as in Example 1, except that the surface layer-forming coating material (F-2) shown in Tables 14-3 and 14-4 was used. Except that the developing roller 31 attached to the process cartridge 20 was changed to developing roller G-2 and the toner to be filled was changed to toner 5, measurements and evaluations were carried out in the same manner as in Example 1. The evaluation results are shown in Tables 14-1 and 14-2. [Table 14-3]

[0300] [Table 14-4] In the table, Me represents a methyl group, Et represents an ethyl group, and Bu represents a butyl group.

[0301] [Examples 4 and 6] Measurements and evaluations were carried out in the same manner as in Example 3, except that the toner filled in the process cartridge 20 was changed to Toner 4 or Toner 1. The evaluation results are shown in Tables 14-1 and 14-2.

[0302] [Example 5] A developing roller G-3 was produced in the same manner as in Example 1, except that the surface layer-forming paint (F-3) shown in Tables 14-3 and 14-4 was used. A developing roller G-3 was used as the developing roller 31 attached to the process cartridge 20, and other measurements and evaluations were carried out in the same manner as in Example 2. The evaluation results are shown in Tables 14-1 and 14-2.

[0303] [Examples 7 to 11] When evaluating the image and the toner irregularity, measurements and evaluations were carried out in the same manner as in Example 2, except that the process speed and the potential difference of the developing blade relative to the developing roller were changed to those shown in Tables 14-1 and 14-2. The evaluation results are shown in Tables 14-1 and 14-2, and in Figures 13 and 14.

[0304] [Example 12] An image of a 4-point letter "E" with a print coverage of 2% of the paper area was continuously printed on 100 sheets at a process speed of 150 mm / sec in normal mode, and then the same image was continuously printed at a process speed of 50 mm / sec, which is one-third the normal mode speed, repeating this process until a total of 8,000 images were printed. The potential difference between the developing blade and the developing roller when printing at a process speed of 150 mm / sec was -100 V, and the potential difference between the developing blade and the developing roller when printing at a process speed of 50 mm / sec was -150 V. All other conditions were the same as in Example 2, and measurements and evaluations were performed. The evaluation results are shown in Tables 14-1 and 14-2.

[0305] [Examples 13 and 14] Measurements and evaluations were carried out in the same manner as in Example 1, except that the toner filled in the process cartridge 20 was changed to Toner 2 or Toner 3. The evaluation results are shown in Tables 14-1 and 14-2.

[0306] [Comparative Example 1] The types and amounts of materials listed in Table 15 below were added to a reaction vessel and stirred. Next, 2-butanone (MEK) was added so that the total solids ratio was 30% by mass, and the mixture was mixed using a sand mill. Next, 2-butanone (MEK) was added to adjust the viscosity of the liquid to within the range of 6 to 10 mPa·s, thereby producing resin layer-forming paint F-4. Developing roller G-4 was produced in the same manner as in Example 1, except that resin layer-forming paint F-1 was replaced with resin layer-forming paint F-4.

[0307] Toner was produced in the same manner as Toner 4, except that the type of external additive was changed as shown in Table 16. The measurement results of Toner 8 obtained are shown in Table 16.

[0308] Measurements and evaluations were carried out in the same manner as in Example 1, except that the developing roller 31 attached to the process cartridge 20 was changed to developing roller G-4 and the toner to be filled was changed to toner 8. The evaluation results are shown in Tables 17-1 and 17-2. [Table 15]

[0309] [Table 16]

[0310] [Table 17-1]

[0311] [Table 17-2] In the table, X is the total amount (mass %) of the compound having the structure represented by structural formula (5) based on the solid content in the coating material for forming a surface layer.

[0312] The impedance value is 1.0 x 10 0 Hz~1.0×10 1 Indicates the minimum impedance value in Hz.

[0313] [Comparative Examples 2, 4, and 6] Measurements and evaluations were carried out in the same manner as in Comparative Example 1, except that the toner filled in the process cartridge 20 was changed to Toner 4, Toner 5, and Toner 1. The evaluation results are shown in Tables 17-1 and 17-2.

[0314] [Comparative Examples 3 and 5] Except for changing the developing roller 31 attached to the process cartridge 20 to the developing roller G-1 or the developing roller G-2, measurements and evaluations were carried out in the same manner as in Comparative Example 1. The evaluation results are shown in Tables 17-1 and 17-2.

[0315] Comparative Example 5 Except for changing the developing roller 31 attached to the process cartridge 20 to the developing roller G-2, measurements and evaluations were carried out in the same manner as in Comparative Example 1. The evaluation results are shown in Tables 17-1 and 17-2.

[0316] [Comparative Examples 7 and 8] When evaluating the image and the toner irregularity, the process speed and the potential difference of the developing blade with respect to the developing roller were changed to those shown in Tables 17-1 and 17-2, respectively, and the same procedures were carried out as in Example 2. The evaluation results are shown in Tables 17-1 and 17-2, Figures 13 and 14.

[0317] Comparative Example 9 Resin layer-forming paint F-5 and developing roller G-5 were prepared in the same manner as in Example 1, except that the additives used in resin layer-forming paint F-1 were changed to the materials and parts by mass shown in Table 18 below. Except that the developing roller 31 attached to the process cartridge 20 was changed to developing roller G-5, measurements and evaluations were carried out in the same manner as in Example 1. The evaluation results are shown in Tables 17-1 and 17-2. [Table 18]

[0318] [Comparative Example 10] [Toner 6] Toner was produced in the same manner as Toner 1, except that the number of parts of hydrolysis liquid added in (polymerization step) was changed as shown in Table 16. The measurement results of Toner 6 obtained are shown in Table 16.

[0319] Measurements and evaluations were carried out in the same manner as in Example 1, except that the toner filled in the process cartridge 20 was changed to Toner 6. The evaluation results are shown in Tables 17-1 and 17-2.

[0320] [Comparative Example 11] [Toner 7] The step (hydrolysis step of the surface layer organosilicon compound) was not performed. Instead, 20 parts of methyltriethoxysilane, an organosilicon compound for the surface layer, was added as a monomer (polymerizable monomer composition preparation step). In the polymerization step, after cooling to 70°C and measuring the pH, no hydrolysis liquid was added. While continuing to stir at 70°C, the slurry was adjusted to pH 9.0 using aqueous sodium hydroxide to complete the condensation, and then held for an additional 300 minutes to form a surface layer. Except for this, Toner 7 was prepared in the same manner as Toner 1. The evaluation results of the obtained Toner 7 are shown in Table 16.

[0321] Measurements and evaluations were carried out in the same manner as in Example 1, except that the toner filled in the process cartridge 20 was changed to Toner 7. The evaluation results are shown in Tables 17-1 and 17-2.

[0322] Examples 1 to 14 showed good results in the evaluations of black after-image fogging, reverse fogging, and image density stability. The evaluation values ​​for toner irregularity also showed good results. This result is believed to be due to the fact that even if the toner deforms due to long-term friction between components and becomes difficult to triboelectrically charge, charge is injected into the toner from the development blade, and leakage of the injected charge to the development roller is suppressed, thereby stabilizing the charge amount of the toner. Toner with low charge tends to be difficult to coat on the development roller. However, by stabilizing the charge amount of the deformed toner, the deformed toner is coated on the development roller, and is consumed on paper through the development process and transfer process, thereby suppressing accumulation in the development container. This is also believed to be the reason for the good results in black after-image fogging and reverse fogging.

[0323] The influence of the developing roller and the toner was compared between Example 1 and Comparative Examples 1 to 3. In Example 1, the conductivity of the external additive as the surface particle was 1×10 -15 S / m or more toner, and and impedance is 1.00×10 6On the other hand, in Comparative Example 2, the conductivity of the external additive as the surface particle is 1×10 -15 Toner of S / m or more and Impedance The ratio is 1.00 x 10 6 In Comparative Example 3, the conductivity of the external additive as the surface particle is 1×10 -15 Toner less than S / m, and impedance is 1. 00×10 6 A developing roller with a resistance of Ω or more was used. Both Comparative Examples 2 and 3 showed poor results in the evaluation value of the toner irregularity, black after fog, and reverse fog. From the above results, it was found that both the conductivity of the toner and the impedance of the developing roller are important characteristics in order to realize the effects of the present invention.

[0324] Examples 1 to 6 and Comparative Examples 1 to 6 show the results of detailed investigations into the conductivity of the external additives or organosilicon polymers used as surface particles, and the impedance of the developing roller, in order to achieve the effects of the present invention. The conductivity of the external additives or organosilicon polymers used as surface particles is 1×10 -15 S / m or more, and the impedance of the developing roller is 1.00 x 1 0 6 By satisfying both Ω or more, good results were obtained in terms of after-black fogging and reverse fogging.

[0325] The evaluation results are shown in Figure 11. Figure 11 is a diagram showing the influence of the impedance of the developing roller and the conductivity of the surface particles on black after-fog and reverse fog. In the figure, conditions under which black after-fog and reverse fog are good are plotted with a circle, and conditions under which black after-fog and reverse fog are bad are plotted with an x. The results show that when the conductivity of the external additive or organosilicon polymer used as the surface particles is 1 x 10 -15 Below S / m, external additives as surface particles or organosilicon polymers form the conductive path. It is presumed that this is because the surface particles do not function as a charge carrier, and the charge is not injected into the toner from the developing blade. In addition, the conductivity of the external additives or organosilicon polymers as surface particles is 1×10 -15 S / m By setting the above, even when a charge is injected into the toner from the developing blade, the impedance of the developing roller is 1.00×10 6 If the resistance is less than Ω or more, it is presumed that the charge injected into the toner will leak to the developing roller side, and the charge will not be imparted to the toner.

[0326] Examples 2, 7 to 11, and Comparative Examples 7 and 8 show the results of a detailed study of the process speed and the potential difference of the developing blade relative to the developing roller in order to achieve the effects of the present invention.

[0327] The evaluation results of the toner irregularity under each condition are shown in Figure 12. Figure 12 is a diagram showing the effect of the potential difference of the developing blade with respect to the developing roller on the evaluation value of the toner irregularity depending on the process speed. When the process speed was slower at 50 mm / sec than at 150 mm / sec, the evaluation value of the toner irregularity in the developing container was smaller, indicating a poor result.

[0328] Furthermore, a separate study showed that the toner charge per unit area (Q / S) was smaller when the process speed was slower at 50 mm / sec than at 150 mm / sec (Figure 13). Figure 13 shows the effect of process speed differences on the charge per unit area due to the potential difference between the developing roller and the developing blade. As mentioned above, this result suggests that when the toner passes through the area facing the developing blade as the developing roller rotates, if the rotational speed of the developing roller is slow, the toner particles pass through in a relatively sparse state, making it difficult for charge to be transferred between the toner particles, and a higher blade voltage must be applied to impart charge to the entire toner. On the other hand, if the rotational speed of the developing roller is fast, toner circulation is more likely to occur in the area just before passing through the area facing the developing roller and the developing blade, and the toner particles pass through in a relatively dense state, making it difficult for charge to be transferred between the toner particles. It is speculated that this may allow the entire toner to be charged even at a low blade voltage.

[0329] Examples 8 and 10 show results obtained at different process speeds when the potential difference between the developing roller and the developing blade was -100V. Faster process speeds resulted in better results in terms of black after-fog and reversed fog (Tables 14-1 and 14-2). The particle size of the deformed toner tended to be approximately 20% smaller than the particle size of the non-deformed toner. Therefore, the inventors considered that in order to impart sufficient charge to the deformed toner, it was necessary to increase the charge amount (Q / S) of the toner per unit area (Q / S) by approximately 20% compared to when there was no potential difference between the developing roller and the developing blade.

[0330] FIG. 14 shows the effect of the potential difference between the developing roller and the developing blade on the charge amount per unit area as a function of process speed. The vertical axis in FIG. 12 is normalized by Q / S when the potential difference between the developing roller and the developing blade is 0 V. As shown in FIG. 14, when the process speed is as fast as 150 mm / sec, the toner charge amount per unit area (Q / S) is more than 1.2 times that when there is no potential difference when the potential difference between the developing roller and the developing blade is -100 V. However, this is not the case when the process speed is 50 mm / sec. Therefore, in order to increase the toner charge amount per unit area (Q / S) to more than 1.2 times that when there is no potential difference between the developing roller and the developing blade under the condition of a process speed of 50 mm / sec, Example 11 is an example in which the potential difference between the developing roller and the developing blade is increased to -150 V with reference to FIG. 14. Example 11 showed better results in terms of black after-image fogging and reverse fogging, even when the process speed was as slow as 50 mm / sec.

[0331] In Example 12, the image was output while varying the potential difference between the developing blade and the developing roller in accordance with the process speed during printing. Good results were obtained for both black after-fog and reversed fog.

[0332] Examples 2, 13, and 14 show the results of examining the effect of the coverage of the organosilicon polymer on the toner particle surface. Better results were obtained by increasing the coverage of the toner particle surface to 45% or more. It is believed that these results are due to the fact that, by satisfying this condition, the organosilicon polymer, which functions as a charging site, significantly increases the opportunities for contact between toner particles, resulting in more effective transfer of charge between toner particles.

[0333] On the other hand, Comparative Examples 1 to 13 show poor results in the evaluation of fogging and the evaluation of image density stability.

[0334] It is believed that Comparative Examples 1 to 6 did not satisfy either the developing roller characteristics or the toner characteristics, or both, and therefore could not stably impart a charge to the toner that had deformed due to long-term use. The developing roller G-4 used in Comparative Examples 1, 2, 4, and 6 uses polyether diol and polycarbonate diol, and both an ether structure and a polycarbonate structure are incorporated into the polyurethane structure. As a result, it is believed that the electrical properties of the polycarbonate structure are inhibited by the ether structure, and the desired impedance value cannot be obtained.

[0335] In Comparative Examples 7 and 8, the potential difference between the developing blade and the developing roller was 0 V, and poor results were obtained in the fogging evaluation and image density stability evaluation. This is presumably because the potential difference between the developing blade and the developing roller was 0 V, so no charge was injected into the toner.

[0336] In Comparative Example 9, the surface potential was too high, and therefore poor results were not obtained in the evaluation of fogging and image density stability. It is believed that the carbon black was coated with an insulating silane coupling agent, which increased the surface potential, resulting in poor results in after-black fogging, reverse fogging, and image density stability.

[0337] In Comparative Example 10, the coverage of the organosilicon polymer was low, resulting in low results in the evaluation of fogging and the evaluation of image density stability. It is believed that the low coverage of the organosilicon polymer prevented sufficient charge from being injected from the developing blade into the entire toner, resulting in poor results in black after-fog, reverse fog, and image density stability.

[0338] In Comparative Example 11, the adhesion rate of the organosilicon polymer was low, resulting in low results for the fog evaluation and image density stability evaluation. This is because the fog worsened with use. It is thought that the low adhesion rate of the organosilicon polymer caused the organosilicon polymer to detach from the toner particles over long-term use, making it impossible for the developing blade to sufficiently inject charge into the entire toner, resulting in black after-fog, reverse fog, and poor image density stability.

[0339] [Configuration 1] a developer carrier that carries a developer; a developer container that contains the developer carrier and a developer containing developer particles; a developing blade that regulates the developer on the developer carrier; an image carrier that carries a developer image; a charging member for charging the image bearing member; A process cartridge comprising: the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface of the substrate, the resin layer contains polyurethane having a polycarbonate structure, A metal film was provided directly on the outer surface of the developer carrier, and a DC voltage of 50 V was applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%. 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 1.00 x 10 6 is greater than or equal to Ω, and 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 disposed so that the distance between the grid portion and the outer surface of the developer carrier was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developer carrier, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier, and the maximum value of the potential of the outer surface was measured 0.06 seconds after the grid portion had passed, and the maximum value of the potential was less than 20.0 V, The surface of the developer particles has a conductivity of 1×10 -15 S / m or more The surface is coated with surface particles, the surface particle coverage is 35% or more, and the surface particle adhesion rate is 80% or more; applying a voltage to the developing blade with a predetermined potential difference relative to the developer bearing member, the predetermined potential difference being the same polarity as the normal charging polarity of the developer; A process cartridge characterized by: [Configuration 2] a developer carrier that carries a developer; a developer container that contains the developer carrier and a developer containing developer particles; a developing blade that regulates the developer on the developer carrier; an image carrier that carries a developer image; a charging member for charging the image bearing member; A process cartridge comprising: the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface of the substrate, the resin layer contains polyurethane having a polycarbonate structure, A metal film was provided directly on the outer surface of the developer carrier, and a DC voltage of 50 V was applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%. 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 × 100 ~1.0×10 1 Impedance at Hz is 1.00 x 10 6 is greater than or equal to Ω, and 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 disposed so that the distance between the grid portion and the outer surface of the developer carrier was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developer carrier, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier, and the maximum value of the potential of the outer surface was measured 0.06 seconds after the grid portion had passed, and the maximum value of the potential was less than 20.0 V, The surface of the developer particles has a conductivity of 1×10 -15 S / m or more The substrate is coated with an organosilicon polymer, the coverage of the organosilicon polymer being 35% or more, and the adhesion rate of the organosilicon polymer being 80% or more. applying a voltage to the developing blade with a predetermined potential difference relative to the developer bearing member, the predetermined potential difference being the same polarity as the normal charging polarity of the developer; A process cartridge characterized by: [Configuration 3] 3. The process cartridge according to claim 2, wherein the covering rate of the surface of the developer particles with the organosilicon polymer is 45% or more. [Configuration 4] 4. The process cartridge according to any one of Configurations 1 to 3, wherein the predetermined potential difference is 150 V or more. [Configuration 5] 5. The process cartridge according to any one of Configurations 1 to 4, wherein the predetermined potential difference is changed in accordance with the process speed. [Configuration 6] 6. The process cartridge according to any one of Configurations 1 to 5, wherein the maximum value of the electric potential of the outer surface of the developer carrier is 10.0 V or less. [Configuration 7] A process cartridge; an exposure device that exposes an image carrier included in the process cartridge; a transfer member for transferring a developer image formed in the process cartridge; An image forming apparatus having 7. An image forming apparatus, wherein the process cartridge is the process cartridge according to any one of configurations 1 to 6. [Configuration 8] a developer carrier that carries a developer; a developer container that contains the developer carrier and a developer containing developer particles; a developing blade that regulates the developer on the developer carrier; an image carrier that carries a developer image; a charging member for charging the image bearing member; an exposure device that exposes the image carrier; a transfer member for transferring the developer image formed on the image carrier; An image forming apparatus comprising: the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface of the substrate, the resin layer contains polyurethane having a polycarbonate structure, a metal film is provided directly on the outer surface of the developer carrier, and when a DC voltage of 50 V is applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%, and an AC voltage having an amplitude of 50 V is applied while changing the frequency between 1.0×10 Hz and 1.0×10 Hz, the impedance at a frequency of 1.0×10 Hz to 1.0×10 Hz is 1.00×10 Ω or more; and 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 disposed so that the distance between the grid portion and the outer surface of the developer carrier was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developer carrier, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier, and the maximum value of the potential of the outer surface was measured 0.06 seconds after the grid portion had passed, and the maximum value of the potential was less than 20.0 V, The surface of the developer particles has a conductivity of 1×10 −15 S / m or more, which is different from that of the developer matrix. The surface is coated with surface particles, the surface particle coverage is 35% or more, and the surface particle adhesion rate is 80% or more; applying a voltage to the developing blade with a predetermined potential difference relative to the developer bearing member, the predetermined potential difference being the same polarity as the normal charging polarity of the developer; An image forming apparatus characterized by: [Configuration 9] a developer carrier that carries a developer; a developer container that contains the developer carrier and a developer containing developer particles; a developing blade that regulates the developer on the developer carrier; an image carrier that carries a developer image; a charging member for charging the image bearing member; an exposure device that exposes the image carrier; a transfer member for transferring the developer image formed on the image carrier; An image forming apparatus comprising: the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface of the substrate, the resin layer contains polyurethane having a polycarbonate structure, a metal film is provided directly on the outer surface of the developer carrier, and when a DC voltage of 50 V is applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%, and an AC voltage having an amplitude of 50 V is applied while changing the frequency between 1.0×10 Hz and 1.0×10 Hz, the impedance at a frequency of 1.0×10 Hz to 1.0×10 Hz is 1.00×10 Ω or more; and 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 disposed so that the distance between the grid portion and the outer surface of the developer carrier was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developer carrier, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier, and the maximum value of the potential of the outer surface was measured 0.06 seconds after the grid portion had passed, and the maximum value of the potential was less than 20.0 V, The surface of the developer particles has a conductivity of 1×10 −15 S / m or more, which is different from that of the developer matrix. The substrate is coated with an organosilicon polymer, the coverage of the organosilicon polymer being 35% or more, and the adhesion rate of the organosilicon polymer being 80% or more. applying a voltage to the developing blade with a predetermined potential difference relative to the developer bearing member, the predetermined potential difference being the same polarity as the normal charging polarity of the developer; An image forming apparatus characterized by: [Explanation of symbols]

[0340] 20: Process cartridge, 21: Photosensitive drum, 23: Charging roller, 30: Developing device, 31: Developing roller, 32: Developing container, 35: Developing blade

Claims

1. a developer carrier that carries a developer; a developer container that contains the developer carrier and a developer containing developer particles; a developing blade that regulates the developer on the developer carrier; an image carrier that carries a developer image; a charging member for charging the image bearing member; A process cartridge comprising: the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface of the substrate, the resin layer contains polyurethane having a polycarbonate structure, A metal film was provided directly on the outer surface of the developer carrier, and a DC voltage of 50 V was applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%. An AC voltage of 50 V amplitude was applied at a frequency of 1.0×10 －１ ~1.0 x 10 ５ When applied while changing between 1.0 x 10 Hz, ０ ~1.0 x 10 １ Impedance at Hz is 1.00 x 10 ６ is greater than or equal to Ω, and 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 disposed so that the distance between the grid portion and the outer surface of the developer carrier was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developer carrier, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier, and the maximum value of the potential of the outer surface was measured 0.06 seconds after the grid portion had passed, and the maximum value of the potential was less than 20.0 V, The surface of the developer particles has a conductivity different from that of the developer matrix of 1×10 -１５ S / m or more The surface is coated with surface particles, the coverage of the surface particles is 35% or more, and the adhesion rate of the surface particles is 80% or more, applying a voltage to the developing blade with a predetermined potential difference relative to the developer bearing member, the predetermined potential difference being the same polarity as the normal charging polarity of the developer; A process cartridge characterized by:

2. a developer carrier that carries a developer; a developer container that contains the developer carrier and a developer containing developer particles; a developing blade that regulates the developer on the developer carrier; an image carrier that carries a developer image; a charging member for charging the image bearing member; A process cartridge comprising: the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface of the substrate, the resin layer contains polyurethane having a polycarbonate structure, A metal film was provided directly on the outer surface of the developer carrier, and a DC voltage of 50 V was applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%. An AC voltage of 50 V amplitude was applied at a frequency of 1.0×10 －１ ~1.0 x 10 ５ When applied while changing between 1.0 x 10 Hz, ０ ~1.0 x 10 １ Impedance at Hz is 1.00 x 10 ６ is greater than or equal to Ω, and 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 disposed so that the distance between the grid portion and the outer surface of the developer carrier was 1.0 mm and the width direction of the grid portion coincided with the axial direction of the developer carrier. A voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier. The potential of the outer surface was measured 0.06 seconds after the grid portion had passed. The maximum value of the potential is less than 20.0 V, The surface of the developer particles has a conductivity different from that of the developer matrix of 1×10 -１５ S / m or more The substrate is coated with an organosilicon polymer, the coverage of the organosilicon polymer being 35% or more, and the adhesion rate of the organosilicon polymer being 80% or more; applying a voltage to the developing blade with a predetermined potential difference relative to the developer bearing member, the predetermined potential difference being the same polarity as the normal charging polarity of the developer; A process cartridge characterized by:

3. 3. The process cartridge according to claim 2, wherein the coating rate of the organosilicon polymer with respect to the surface of the developer particles is 45% or more.

4. 4. A process cartridge according to claim 1, wherein said predetermined potential difference is 150 V or more.

5. 4. The process cartridge according to claim 1, wherein the predetermined potential difference is changed in accordance with a process speed.

6. 4. The process cartridge according to claim 1, wherein the maximum value of the potential of the outer surface of said developer carrying member is 10.0 V or less.

7. A process cartridge; an exposure device that exposes an image carrier included in the process cartridge; a transfer member for transferring a developer image formed in the process cartridge; An image forming apparatus having 4. An image forming apparatus, wherein the process cartridge is the process cartridge according to claim 1.

8. a developer carrier that carries a developer; a developer container that contains the developer carrier and a developer containing developer particles; a developing blade that regulates the developer on the developer carrier; an image carrier that carries a developer image; a charging member for charging the image bearing member; an exposure device that exposes the image carrier; a transfer member for transferring the developer image formed on the image carrier; An image forming apparatus comprising: the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface of the substrate, the resin layer contains polyurethane having a polycarbonate structure, a metal film is provided directly on the outer surface of the developer carrier, and when a DC voltage of 50 V is applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%, and an AC voltage having an amplitude of 50 V is applied while changing the frequency between 1.0×10 Hz and 1.0×10 Hz, the impedance at a frequency of 1.0×10 Hz to 1.0×10 Hz is 1.00×10 Ω or more; 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 disposed so that the distance between the grid portion and the outer surface of the developer carrier was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developer carrier, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier, and the maximum value of the potential of the outer surface was measured 0.06 seconds after the grid portion had passed, and the maximum value of the potential was less than 20.0 V, The surface of the developer particles has a conductivity of 1×10 −15 S / m or more, which is different from that of the developer base. The surface is coated with surface particles, the coverage of the surface particles is 35% or more, and the adhesion rate of the surface particles is 80% or more, applying a voltage to the developing blade with a predetermined potential difference relative to the developer bearing member, the predetermined potential difference being the same polarity as the normal charging polarity of the developer; An image forming apparatus characterized by:

9. a developer carrier that carries a developer; a developer container that contains the developer carrier and a developer containing developer particles; a developing blade that regulates the developer on the developer carrier; an image carrier that carries a developer image; a charging member for charging the image bearing member; an exposure device that exposes the image carrier; a transfer member for transferring the developer image formed on the image carrier; An image forming apparatus comprising: the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface of the substrate, the resin layer contains polyurethane having a polycarbonate structure, a metal film is provided directly on the outer surface of the developer carrier, and when a DC voltage of 50 V is applied between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%, and an AC voltage having an amplitude of 50 V is applied while changing the frequency between 1.0×10 Hz and 1.0×10 Hz, the impedance at a frequency of 1.0×10 Hz to 1.0×10 Hz is 1.00×10 Ω or more; 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 disposed so that the distance between the grid portion and the outer surface of the developer carrier was 1.0 mm and the direction of the width of the grid portion coincided with the axial direction of the developer carrier, a voltage of 8 kV was applied to the grid portion, and the corona discharger was moved relatively along the axial direction of the developer carrier at a speed of 400 mm / sec to charge the outer surface of the developer carrier, and the maximum value of the potential of the outer surface was measured 0.06 seconds after the grid portion had passed, and the maximum value of the potential was less than 20.0 V, The surface of the developer particles has a conductivity of 1×10 −15 S / m or more, which is different from that of the developer base. The substrate is coated with an organosilicon polymer, the coverage of the organosilicon polymer being 35% or more, and the adhesion rate of the organosilicon polymer being 80% or more; applying a voltage to the developing blade with a predetermined potential difference relative to the developer bearing member, the predetermined potential difference being the same polarity as the normal charging polarity of the developer; An image forming apparatus characterized by:

Images