Electrophotographic cleaning blade, process cartridge, and electrophotographic image forming apparatus

Abstract

To provide a cleaning blade that can stably exhibit excellent cleaning performance over a long period.SOLUTION: A cleaning blade for electrophotography is provided with an elastic member containing polyurethane and a support member supporting the elastic member, and cleans the surface of a moving member to be cleaned by bringing a part of the elastic member into contact with the member to be cleaned. In an 8°C environment, when the storage elastic modulus of the elastic member at an oscillation frequency of 1×10-3 Hz is defined as E'(1), and the storage elastic modulus of the elastic member at an oscillation frequency of 1×104 Hz as E'(2), E'(1) is 12.0-18.0 MPa, and E'(2) is 530.0-1500.0 MPa.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an electrophotographic cleaning blade, a process cartridge, and an electrophotographic image forming apparatus used in an electrophotographic image forming apparatus.

Background Art

[0002] Some electrophotographic image forming apparatuses (hereinafter also referred to as electrophotographic apparatuses) include a cleaning member for removing toner remaining on the surface of an electrostatic latent image carrier such as a photoreceptor or an intermediate transfer body even after transferring a toner image onto a transfer body. One such cleaning member is an electrophotographic cleaning blade (hereinafter also simply referred to as a cleaning blade). Hereinafter, a member whose surface is cleaned by bringing the cleaning blade into contact therewith, for example, an electrostatic latent image carrier or an intermediate transfer body, may be referred to as a member to be cleaned. In recent years, with the further extension of the service life of electrophotographic apparatuses, it has been required that the cleaning blade also exhibits excellent cleaning performance stably over a long period. The applicant of the present application disclosed in Patent Document 1 an electrophotographic cleaning blade provided with an elastic member containing polyurethane, which is excellent in chipping resistance and can stably exhibit excellent cleaning performance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present inventors have conducted further studies on the electrophotographic cleaning blade described in Patent Document 1. In the process, they identified a problem that needed to be solved with the electrophotographic cleaning blade. The electrophotographic cleaning blade uses polymeric MDI as the raw material for polyurethane. This suppresses the aggregation of hard segments in the polyurethane and finely disperses the hard segments, resulting in excellent cleaning performance.

[0005] However, in the electrophotographic cleaning blade described in Patent Document 1, polymeric MDI is used as the raw material, resulting in a relatively high elastic modulus when the cleaning blade is in contact with the material to be cleaned in a stationary state. Therefore, the nip width when the cleaning blade is in contact with the material to be cleaned tends to be narrow, around a few micrometers. While a narrow nip width is advantageous in increasing the contact pressure of the cleaning blade against the material to be cleaned, it has become clear that a narrow nip width can lead to problems when scratches occur on the contact surface of the cleaning blade on the material to be cleaned during the long-term use of the electrophotographic device, resulting in poor cleaning in those scratched areas.

[0006] At least one aspect of this disclosure is toward providing a cleaning blade that can stably exhibit excellent cleaning performance over a long period of time. At least one aspect of this disclosure is toward providing a process cartridge that contributes to the formation of high-quality electrophotographic images. Furthermore, at least one aspect of this disclosure is toward providing an electrophotographic image forming apparatus that can stably form high-quality electrophotographic images. [Means for solving the problem]

[0007] This disclosure relates to an electrophotographic cleaning blade comprising an elastic member containing polyurethane and a support member for supporting the elastic member, wherein a portion of the elastic member is brought into contact with the surface of a moving member to be cleaned to clean the surface of the member to be cleaned, In an 8°C environment, the vibration frequency of the elastic member is 1 × 10⁻⁶. -3 Let E'(1) be the storage modulus at Hz, and the vibration frequency be 1 × 10⁻⁶. 4 When the storage modulus at Hz is E'(2), E'(1) is 12.0~18.0 MPa, The present invention relates to an electrophotographic cleaning blade characterized in that E'(2) is 530.0 to 1500.0 MPa. [Effects of the Invention]

[0008] According to at least one aspect of this disclosure, a cleaning blade capable of stably exhibiting excellent cleaning performance over a long period of time can be obtained. Furthermore, according to at least one aspect of this disclosure, a process cartridge that contributes to the formation of high-quality electrophotographic images can be obtained. Moreover, according to at least one aspect of this disclosure, an electrophotographic image forming apparatus capable of stably forming high-quality electrophotographic images can be obtained. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic perspective view of an electrophotographic cleaning blade according to one aspect of the present disclosure. [Figure 2] This diagram shows the state in which the edge of the cleaning blade is in contact with the object being cleaned when the process cartridge is stationary. [Figure 3] A diagram showing how to measure nip width. [Figure 4] A diagram illustrating the method for measuring stick-slip. [Figure 5] A master curve showing the relationship between the storage modulus of elasticity and the measurement frequency for the elastic members of Example 1 and Comparative Example 1. [Modes for carrying out the invention]

[0010] In this disclosure, descriptions of numerical ranges such as "XX or greater and YY or less" or "XX to YY" mean a numerical range that includes the lower and upper limits, unless otherwise specified. When numerical ranges are described in steps, the upper and lower limits of each numerical range can be combined in any way.

[0011] The inventors of this invention conducted extensive research with the aim of obtaining a cleaning blade that can stably exhibit excellent cleaning performance even when scratches occur on the surface of the object to be cleaned during the course of long-term use. In the process, the inventors considered increasing the nip width between the cleaning blade and the object to be cleaned by reducing the elastic modulus of the elastic member, thereby stabilizing the contact between the cleaning blade and the object to be cleaned. On the other hand, increasing the nip width reduces the contact pressure per unit area at the nip, which leads to a decrease in cleaning performance. Furthermore, reducing the elastic modulus of the cleaning blade makes it easier for so-called stick-slip to occur. Stick-slip refers to the phenomenon where the tip of the elastic member of the cleaning blade is stretched in the direction of movement of the object to be cleaned, and then returns to its original shape due to its elasticity. When this stick-slip occurs, toner and external additives can easily slip past the cleaning blade, leading to poor cleaning.

[0012] Therefore, the inventors conducted further studies to achieve a higher level of balance between ensuring sufficient nip width and excellent cleaning performance. As a result, they found that the storage modulus of the elastic member of the cleaning blade with respect to a specific vibration frequency in a low-temperature environment of 8°C was low frequency (1 × 10⁻⁶). -3 Let E'(1) be the storage modulus at Hz, and let E'(1) be the storage modulus at high frequencies (1 × 1 0 4 When the storage modulus at Hz is E'(2), we found that setting E'(1) to 12.0-18.0 MPa and E'(2) to 530.0-1500.0 MPa is effective in achieving a higher level of balance between ensuring sufficient nip width and excellent cleaning performance.

[0013] The fact that E'(1) is within the range of 12.0 to 18.0 MPa indicates that the elastic member is sufficiently soft in a steady state when the object to be cleaned and the cleaning blade are in stationary contact. This ensures that a sufficient nip width can be secured between the elastic member of the cleaning blade and the object to be cleaned. On the other hand, the fact that E'(2) is within the range of 530.0 to 1500.0 MPa indicates that the elastic member is sufficiently rigid when the member to be cleaned and the cleaning blade are in contact while moving relative to each other and vibration is applied to the elastic member. This improves the ability to scrape off dirt from the surface of the member to be cleaned and suppresses stick-slip caused by the contact portion of the elastic member with the member to be cleaned being stretched in the direction of movement of the member to be cleaned.

[0014] Even in conventional elastic members containing polyurethane, the storage modulus tends to increase as the vibration frequency increases. However, an elastic member containing polyurethane that achieves both a sufficiently low storage modulus at low frequencies and a sufficiently high storage modulus at high frequencies, as described above, is considered unprecedented.

[0015] The following describes a cleaning blade relating to one aspect of this disclosure. Examples of components to be cleaned that can be cleaned with an electrophotographic cleaning blade according to one aspect of this disclosure (hereinafter also simply referred to as the "cleaning blade") include image carriers such as photoreceptors and endless belts such as intermediate transfer belts. Hereinafter, an embodiment of the cleaning blade according to one aspect of this disclosure will be described in detail using an image carrier as an example of a component to be cleaned, but this disclosure is not limited thereto. In the following description, components having the same function may be given the same number in the drawings and their descriptions may be omitted.

[0016] <Cleaning blade configuration> The cleaning blade comprises an elastic member containing polyurethane and a support member that supports the elastic member, and cleans the surface of the moving member to be cleaned by bringing a part of the elastic member into contact with the surface of the member to be cleaned. Figure 1 is a schematic perspective view of a cleaning blade 1 according to one aspect of the present disclosure. The cleaning blade 1 comprises an elastic member 2 and a support member 3 that supports the elastic member 2. Figure 2 is a schematic cross-sectional view showing a cleaning blade according to one embodiment of the present disclosure in contact with a member to be cleaned. The elastic member 2 has a main surface 4 facing the member to be cleaned 6 and a tip surface 5 that together with the main surface 4 forms the tip edge. 7 indicates the rotation direction of the member to be cleaned.

[0017] <Analysis of Cleaning Phenomena: Vibration and Cleaning> The inventors conducted a detailed analysis of the behavior of the contact portion (tip of the elastic member) of the elastic member when the cleaning blade is in contact with a stationary member, and the behavior of the tip of the elastic member when the cleaning blade is in contact with a moving member. As a result, they found that the nip width between the cleaning blade and the member to be cleaned, and the cleaning performance, are related to the stored modulus of elasticity of the elastic member at the first and second vibration frequencies described below.

[0018] <Storage modulus E'(1) at the first vibration frequency> With respect to the nip width between the cleaning blade and the object to be cleaned, the vibration frequency is 1 × 10⁻⁶ -3 The storage modulus of elasticity of the elastic component of the cleaning blade at Hz (hereinafter also referred to as the "first vibration frequency") is important.

[0019] Since the cleaning blade remains in contact with the photoreceptor even when not in operation, the nip between the cleaning blade and the object to be cleaned is formed in a state of sufficient stress relief. The first vibration frequency related to the contact in the steady state between the cleaning blade and the member to be cleaned can be obtained by the following method. The elastic member of the cleaning blade is brought into contact with one surface of a transparent flat glass plate, and while moving the glass plate in a direction orthogonal to the longitudinal direction of the cleaning blade, the nip state is observed from the other surface side of the flat glass plate using a laser microscope. At this time, it can be observed that the nip width widens as the contact leaving time between the flat glass plate and the cleaning blade is extended. The widening of this nip converges at about 1×10 -3 Hz. From this, the vibration frequency related to the contact state between the cleaning blade and the member to be cleaned is considered to be 1×10 -3 Hz. Therefore, the storage elastic modulus at 1×10 -3 Hz affects the nip width.

[0020] The nip width is preferably 17 μm or more, more preferably 18 μm or more, and still more preferably 19 μm or more in order to prevent toner and external additives from passing through the nip portion at the site where the damage occurs when the member to be cleaned is damaged. Also, from the viewpoint of ensuring the contact pressure of the cleaning blade against the member to be cleaned, it is preferably 25 μm or less, particularly preferably 24 μm or less, and still more preferably 23 μm or less. Examples of the nip width include preferably the range of 17 to 25 μm, 19 to 24 μm, and 20 to 23 μm.

[0021] <Storage elastic modulus E´(2) at the second vibration frequency> The vibration frequency (second vibration frequency) related to stick-slip at the tip of the cleaning blade that contacts the member to be cleaned is 1×10 4 Hz. The vibration frequency related to stick-slip can be measured by the following method. With the elastic part of the cleaning blade in contact with the electrophotographic photosensitive drum, which is the component to be cleaned, the electrophotographic photosensitive drum was rotated (at a rotation speed of 150 rpm) while a small amount of toner was supplied, and the movement of the tip of the contact part of the cleaning blade was observed using a laser displacement meter. As a result, 1 × 10⁻⁶ 4 Displacement was observed with a period of Hz. This indicates that the tip of the cleaning blade moved 1 × 10⁻⁶ times due to stick-slip. 4 This suggests that it is moving with a period of Hz. Therefore, it relates to stick-slip, 1 × 10⁻⁶. 4 The storage modulus at Hz is thought to influence the stick-slip width.

[0022] When stick-slip occurs, toner and external additives present near the nip may not be completely scraped off and may pass through the cleaning blade. Therefore, by reducing the amount of vibration of the cleaning blade caused by stick-slip, the possibility of toner and external additives passing through the cleaning blade can be reduced, and as a result, cleaning performance can be improved.

[0023] Specifically, the stick-slip width measured under the conditions described in the [Stick-Slip Evaluation] section of the examples described later is preferably 20 μm or less, more preferably 17 μm or less, and even more preferably 15 μm or less. A smaller stick-slip width is preferable, and there is no particular lower limit. For example, preferred ranges include 0 to 15 μm, 0 to 17 μm, and 0 to 20 μm.

[0024] <Dynamic Viscoelasticity and Cleaning> As described above, based on the finding that vibration of the elastic component of the cleaning blade is closely related to the cleaning phenomenon, the inventors focused on the frequency dependence of the dynamic viscoelasticity of the urethane material and proceeded with their investigation. The inventors have found that, for example, a cleaning blade in the form described below can exhibit excellent cleaning performance even in long-life systems.

[0025] Specifically, in an 8°C environment, the elastic member has the following characteristics: The vibration frequency is 1 × 10 ―3 Let E'(1) be the storage modulus of the elastic member at Hz, and the vibration frequency be 1 × 10⁻⁶. 4 When the storage modulus of elastic material at Hz is E'(2), E'(1) is between 12.0 and 18.0 MPa, and E'(2) is between 530.0 and 1500.0 MPa.

[0026] Vibration frequency 1 × 10 ―3 The storage modulus E'(1) of the elastic member at Hz affects the formation of an appropriate nip width. If E'(1) is 18.0 MPa or less, the elastic member is sufficiently soft when it comes into contact with the stationary material to be cleaned and forms a nip, ensuring an appropriate nip width. This allows for maintaining contact even during long-term use and suppresses the leakage of toner and external additives. Furthermore, if E'(2) is 12.0 MPa or more, it prevents the nip width from becoming excessively large due to the elastic member being too soft. As a result, the contact pressure of the cleaning blade against the material to be cleaned at the nip can be properly maintained.

[0027] E'(1) is more preferably 17.5 MPa or less, and even more preferably 17.0 MPa or less. It is also more preferably 12.5 MPa or more, and even more preferably 13.0 MPa or more. For example, it is preferably in the range of 12.5 to 17.5 MPa and 13.0 to 17.0 MPa. The value of E'(1) can be controlled by the molecular motion of the components constituting the elastic member. Specific control methods will be described later.

[0028] Vibration frequency 1 × 10 4 The storage modulus E'(2) of the elastic member at Hz affects the suppression of stick-slip. When E'(2) is within the range of 530.0 MPa to 1500.0 MPa, the cleaning blade is 1 × 10⁻⁶ 4This means that when vibrated at Hz, the tip of the elastic component of the cleaning blade is less likely to move, i.e., it is less likely to be stretched in the direction of movement of the object being cleaned. As a result, stick-slip can be suppressed, and toner and external additives can be prevented from passing through.

[0029] E'(2) must be 750.0 MPa or higher from the standpoint of suppressing stick-slip. It is preferable that it be 950.0 MPa or higher, and more preferably that it be 950.0 MPa or higher. E'(2) is, for example, Preferably, the pressure range is 750.0 to 1500.0 MPa, and particularly preferably, 950.0 to 1500.0 MPa. The value of E'(2) can be controlled by the molecular motion of the components constituting the elastic member. Specific control methods will be described later.

[0030] The elastic member contains polyurethane. The polyurethane (specifically, polyurethane elastomer) consists of, for example, hard segments and soft segments. In this disclosure, the hard segment refers to components with low molecular mobility at and near crosslinking points, such as aggregated crystalline components of urethane bonds, nurate bonds, polymeric MDI, and trimethylolpropane. The soft segment refers to segments with high molecular mobility between crosslinking points.

[0031] The modulus of elasticity in the low-frequency region, such as E'(1), reflects the overall mobility of the polyurethane molecule. Therefore, it is affected by both the molecular mobility of the hard segment and the molecular mobility of the soft segment. In the low-frequency region, there is sufficient time for relaxation, allowing the soft segment, which is a component with high molecular mobility, to move freely and thus contributing little to the elastic modulus. However, the hard segment, which is a component with low molecular mobility, cannot move freely, and the magnitude of its molecular mobility contributes to the elastic modulus. In other words, the greater the molecular mobility of the hard segment, the smaller E'(1) becomes, and the smaller the molecular mobility of the hard segment, the larger E'(1) becomes. Therefore, for polyurethane in an elastic member according to one aspect of this disclosure, it is essential to increase the molecular mobility of the hard segment.

[0032] On the other hand, in the high-frequency region, the relaxation time is short, so the soft segments cannot move freely, and the magnitude of their molecular mobility contributes to the elastic modulus. On the other hand, the hard segments cannot move sufficiently. Therefore, when the soft segments become unable to move freely, the entire polymer freezes, and the elastic modulus increases rapidly. Consequently, in the high-frequency region, the molecular mobility of the soft segments has a more significant influence on the storage modulus than the molecular mobility of the hard segments. In other words, the greater the molecular mobility of the soft segments, the smaller E'(2) becomes, and the smaller the molecular mobility of the soft segments, the larger E'(2) becomes. Therefore, for polyurethane in an elastic member according to one aspect of this disclosure, it is important to reduce the molecular mobility of the soft segments.

[0033] As described above, E'(1) can be controlled primarily by adjusting the molecular mobility of the hard segment, and E'(2) can be controlled primarily by adjusting the molecular mobility of the soft segment. The molecular mobility of hard segments decreases as rigid components such as nurate bonds in polyurethane, crosslinking regions derived from polymeric MDI, and crystalline structures formed by interactions between soft segments increase, and increases as the crosslinking points become more flexible.

[0034] Therefore, in order to reduce E'(1), it is preferable to use as little polymeric MDI as possible as a raw material for polyurethane, and in particular, it is preferable to use it completely. Furthermore, in order to prevent the formation of crystalline components due to the interaction of soft segment portions, it is preferable to use trimethylolpropane (TMP) as a crosslinking component. By introducing a crosslinking structure derived from TMP into the polyurethane, the soft segment portions present between these crosslinking structures become less likely to interact with each other due to the steric hindrance of the TMP-derived crosslinking structures. As a result, the formation of crystalline structures (crystalline components), i.e., hard segments, due to the interaction of soft segments is inhibited.

[0035] Furthermore, because trimethylolpropane has a methylene skeleton next to the hydroxyl group, a molecularly flexible crosslinked structure is formed. As a result, the polyurethane according to one aspect of this disclosure has greater molecular mobility of the hard segment and a smaller E'(1) compared to polyurethane having a rigid crosslinked structure derived from polymeric MDI.

[0036] The molecular mobility of soft segments can be controlled by the crosslinking density. A higher crosslinking density results in smaller molecular weights between crosslinking points, reducing the space available for the soft segments to move freely, thus decreasing molecular mobility. Furthermore, maximizing the length of the soft segments between crosslinking points is also effective in suppressing the molecular mobility of soft segments. Furthermore, equalizing the length of the soft segments can make the rise in the storage modulus from the low-frequency range to the high-frequency range in the master curve steeper. Therefore, E'(1) is in the range of 12.0~18.0 MPa, and E'(2) is 530.0~ Elastic members within the range of 1500.0 MPa can be obtained more easily.

[0037] To obtain a polyurethane with a short distance between crosslinking points and a uniform length between crosslinking points, it is preferable, for example, to set the number-average molecular weight of the prepolymer used as a raw material for the polyurethane to within the range of 8,000 to 12,000, and to use as few chain extenders as possible, such as 1,4-butanediol, and in particular, it is preferable to use no chain extenders at all. An example of the measurement conditions for the number-average molecular weight of the prepolymer is as follows: Device: HLC-8320GPC (product name, manufactured by Tosoh) Column: TSKgel SuperMultiporeHZ-N (product name, manufactured by Tosoh; 4.6mm ID x 15cm) Eluent: THF Flow rate: 0.35mL / min Sample: 0.5 wt% THF solution Injection volume: 10μL Detector: RI Temperature: 40℃ Standard material: Polystyrene

[0038] Specifically, by making the molecular mobility of the hard segment large and the molecular mobility of the soft segment small, an elastic member with a small E'(1) and a large E'(2) can be obtained. As a result, an elastic member different from conventional ones can be obtained that can achieve both the formation of an appropriate nip width and the suppression of stick-slip.

[0039] The elastic member of the cleaning blade described in Patent Document 1 uses polymeric MDI as a polyurethane raw material to refine and disperse the hard segments. As a result, the crosslinking points derived from polymeric MDI become rigid, and the molecular mobility of the hard segments decreases. Therefore, it is thought that the value of E'(1) is not as small as that of the cleaning blade described in this disclosure. A specific example will be shown in Comparative Example 1, which will be described later. Consequently, it is thought that the cleaning blade described in Patent Document 1 tends to have a narrower nip width compared to the cleaning blade described in this disclosure. Therefore, there is room for improvement in the cleaning performance of the cleaning blade described in Patent Document 1 when used on a scratched object to be cleaned.

[0040] Furthermore, although the cleaning blade for electrophotographic apparatus described in Patent Document 2 uses trimethylolpropane as a crosslinking component in the examples, the amount added is small. As a result, it is thought that in the polyurethane described in Patent Document 2, a crystalline structure is easily formed due to the aggregation of soft segments, resulting in a large storage modulus in the low-frequency range. In addition, Patent Document 2 discloses the use of a chain extender such as 1,4-butanediol as a raw material for polyurethane. Therefore, it is thought that the length between crosslinking points of the soft segments is non-uniform. As a result, the master curve showing the relationship between vibration frequency and storage modulus does not rise steeply, and it is thought that the storage modulus in the high-frequency range is not sufficiently high. Therefore, the cleaning blade for electrophotographic apparatus described in Patent Document 2 may have a narrow nip width and stick-slip may not be sufficiently suppressed.

[0041] As described above, securing nip width and suppressing stick-slip tend to be contradictory. In contrast, the elastic member used in the cleaning blade according to this disclosure can suppress stick-slip while forming an appropriate nip width by making E'(1) smaller while making E'(2) larger, in other words, by making the master curve showing the relationship between the storage modulus of elasticity and vibration frequency steeper.

[0042] <Method for measuring the storage modulus> E'(1) and E'(2) are obtained by measuring the dynamic viscoelasticity of the sample using a dynamic viscoelastic apparatus under conditions where the frequency and temperature are arbitrarily set, and creating a master curve at a reference temperature of 8°C from the measurement data. The master curve is created based on the temperature-time superposition rule. The horizontal axis represents frequency, and the vertical axis represents the modulus of elasticity. It can be created by shifting the frequency dispersion data measured at each temperature horizontally so that it overlaps with the data at the reference temperature.

[0043] From the obtained master curve, for example, by curve fitting based on a generalized Maxwell model and formulating it mathematically, 1 × 10 ―3 The storage modulus E'(1) of an elastic member at Hz, and 1 × 10⁻⁶ 4 The storage modulus E'(2) of an elastic member at Hz can be calculated. The reason the measurement temperature for the storage modulus was set at 8°C is that when a printer is used in a low-temperature range like 8°C, the toner tends to become electrically charged, increasing its adhesion to the photoreceptor, which makes cleaning more difficult.

[0044] The molecular mobility of soft and hard segments can be evaluated by the spin-spin relaxation time T2 (transverse relaxation time) in pulsed NMR. In pulsed NMR measurements at 50°C, the spin-spin relaxation time (T2) of the soft segment when separated into two components, the hard segment and the soft segment, was observed. L ) is preferably 250 to 320 μs. When the molecular mobility of the soft segment is high, relaxation takes a long time, therefore the spin-spin relaxation time (T2) of the soft segment is long. L ) will become larger.

[0045] The spin-spin relaxation time T2 is measured using the solid echo method with a pulsed NMR spectrometer. A pulsed NMR spectrometer is a device used to evaluate the mobility of polymer molecules such as rubber based on the mobility (relaxation time) of hydrogen atoms in the molecular chain. In this embodiment, the solid echo method is used as the sequence. The solid echo method using a pulsed NMR spectrometer is not particularly limited and can be performed using known methods.

[0046] By measuring the spin-spin relaxation time T2 of the elastic component of the cleaning blade using pulsed NMR, a T2 relaxation curve (free induction decay curve) can be obtained. The specific measurement methods will be described later.

[0047] T2 L If the interval is less than 250 μs, E'(1) tends to be large. On the other hand, T2 L When the interval exceeds 320 μs, E'(2) tends to decrease. T2 L The fact that the interval is between 250 and 320 μs makes it easier for E'(1) and E'(2) to satisfy the specific range mentioned above.

[0048] T2 L It is more preferably 260 μs or more, and even more preferably 270 μs or more. It is also more preferably 310 μs or less, and even more preferably 300 μs or less. For example, preferred ranges include 260 to 310 μs and 270 to 300 μs. T2 L This can be controlled by the molecular mobility of the soft segments. Furthermore, the molecular mobility of the soft segments can be controlled by the crosslinking density. The higher the crosslinking density, the smaller the molecular weight between crosslinking points, and the smaller the space in which the soft segments can move freely, thus reducing molecular mobility.

[0049] Furthermore, in pulsed NMR measurements at a 50°C environment, the T2 relaxation time of the hard segment (T2) when the hard segment is separated into two components, the hard segment and the soft segment. S ) is preferably 52 to 85 μs. T2 SIf the interval is less than 52 μs, E'(1) tends to be large. On the other hand, T2 S ga 85 When the value exceeds μs, E'(2) tends to become smaller. T2 S Since the interval is between 52 and 85 μs, E'(1) and E'(2) can satisfy the above specific range.

[0050] <Means of achievement> This paper describes specific means for controlling the molecular mobility of soft and hard segments in order to reduce E'(1) and increase E'(2). <Molecular Motility of Hard Segments> The molecular mobility of hard segments is influenced by the rigid components within the molecule. These rigid components are nurates and crystals, and reducing them can increase the molecular mobility of hard segments. Therefore, it is desirable to minimize nurate bonds and make the molecule urethane-rich. Specifically, this is as follows. In FT-IR measurements of an elastic material using diamond as the ATR crystal, 1415 cm² was obtained. -1 The peak intensity was 1538 cm. -1 The value of the ratio to the peak intensity (1415cm) ―1 Peak intensity / 1538cm ―1 The peak intensity of the signal is preferably 0.50 to 0.65.

[0051] FT-IR analysis of elastic materials using diamond as the ATR crystal at 1415 cm² -1 The peak corresponds to the isocyanurate ring. Meanwhile, at 1538 cm -1 The peak corresponds to the NH angle change of the urethane bond. That is, 1415 cm. ―1 Peak intensity / 1538cm ―1 A peak intensity value in the range of 0.50 to 0.65 indicates that there are few nurate bonds in the elastic member.

[0052] 1415cm -1 Peak intensity / 1538cm -1A peak intensity value (peak intensity ratio) greater than 0.65 indicates the presence of many nurate bonds in the elastic member. Therefore, the rigidity of the nurate reduces the molecular mobility of the hard segment, making E'(1) larger. On the other hand, 1415cm -1 Peak intensity / 1538cm -1 If the peak intensity value is less than 0.50, E'(1) tends to become too small; therefore, a value between 0.50 and 0.65 is preferable. 1415cm -1 Peak intensity / 1538cm -1 The peak intensity value is preferably 0.53 to 0.65.

[0053] 1415cm -1 Peak intensity / 1538cm -1 To bring the peak intensity values ​​within the specific range mentioned above, methods such as reducing the number of nurate bonds and enriching the urethane content can be employed. Specifically, this includes avoiding catalysts that promote nurate formation and using urethane catalysts, bringing the ratio of -NCO to -OH in the prepolymer closer to 1, and keeping the reaction temperature when reacting the prepolymer materials below 100°C.

[0054] Within the limits of satisfying E'(1) and E'(2), polyurethane may have a rigid structure as a constituent component, such as polymeric MDI. Specifically, this is shown below.

[0055] When the side of the cleaning blade that contacts the surface of the member to be cleaned is defined as the tip side of the cleaning blade, the elastic member has a plate shape having at least at the tip side a main surface (4) that faces the member to be cleaned and a tip surface (5) that together with the main surface forms the tip edge. Assume that a third line segment is drawn on the tip surface parallel to the tip edge, with a distance of 0.5 mm from the tip edge. Let the length of the third line segment be L', and let the points 1 / 8L', 1 / 2L', and 7 / 8L' from one end of the third line segment be P0', P1', and P2', respectively. The samples sampled at each of P0', P1', and P2' are heated and vaporized in an ionization chamber, and the sample molecules are ionized using a direct sample introduction type mass spectrometer, which is heated to 1000°C at a heating rate of 10°C / s. The resulting total ion detection amount is M1, and the m / z value derived from polymeric MDI is in the range of 380.5 to 381.5. Let M2 be the integrated intensity of the peak in the extracted ion thermogram corresponding to the area. In this case, it is preferable that M2 / M1 is less than 0.0010.

[0056] It is preferable to use 4,4'-MDI as the isocyanate, which is highly reactive and has two isocyanate groups with equivalent reactivity. On the other hand, as mentioned above, it is preferable to minimize the use of polymeric MDI, which is a trifunctional MDI, and in particular, it is preferable not to use it at all. Specifically, it is preferable that M2 / M1 is less than 0.0010. When M2 / M1 satisfies the above specific range, E'(1) is more likely to satisfy a good range. M2 / M1 is more preferably 0.0009 or less. A smaller M2 / M1 is preferable, and there is no particular lower limit, but it is preferably 0.0000 or more. When M2 / M1 is greater than or equal to 0.0010, E'(1) tends to be large due to the rigidity of polymeric MDI.

[0057] Furthermore, in order to increase the molecular mobility of the hard segments, it is preferable to minimize the amount of crystalline structure. Specifically, it is preferable to minimize materials that easily form crystalline structures, such as 1,4-butanediol, and to enrich the material with a crosslinking agent such as trimethylolpropane. A crosslinking agent such as trimethylolpropane makes it easier to create distance between urethane bonds, making it difficult for crystalline structures to form.

[0058] <Molecular Motility of Soft Segments> The molecular mobility of soft segments is easily influenced by the distance between crosslinking points and the structure between crosslinking points. Therefore, for example, by shortening the distance between crosslinking points and increasing the concentration of ester groups in the polyol, the molecular mobility of soft segments can be reduced. One way to shorten the distance between crosslinking points is to increase the concentration of the crosslinking agent in the raw material composition of the elastic member. The distance between crosslinking points is preferably around 6000 to 9000 g / mol, although this also depends on the ester group concentration. The concentration of the crosslinking agent in the raw material composition of the elastic member is preferably 0.30 to 0.70 mmol / g, more preferably 0.40 to 0.61 mmol / g, and even more preferably 0.50 to 0.60 mmol / g, taking into account the molecular mobility of the hard segment mentioned above.

[0059] The method for calculating the crosslinking agent concentration is described below. For example, it can be quantified by pyrolysis GC / MS. Polyhydric alcohols are detected by pyrolysis GC / MS. The measurement conditions are as follows. Device: Pyrolysis apparatus: EGA / PY-3030D (product name, manufactured by Frontier Lab Co., Ltd.) Gas chromatography apparatus: TRACE1310 gas chromatograph (product name, manufactured by Thermo Fisher Scientific) Mass spectrometer: ISQLT (product name, manufactured by Thermo Fisher Scientific) Pyrolysis temperature: 500℃ GC Column: 0.25mm inner diameter x 30m stainless steel capillary column Stationary phase: 5% phenylpolydimethylsiloxane Heating conditions: Hold at 50°C for 3 minutes, then increase temperature to 300°C at a rate of 8°C / minute. MS conditions: Mass number range m / z10~650 Scan speed: 1 second / scan The type of polyhydric alcohol is qualitatively determined by GC / MS. A calibration curve is created using GC analysis of known concentrations of the qualitatively determined polyhydric alcohol type, and quantification is performed from the GC peak area ratio to calculate the crosslinking agent concentration in the raw material composition.

[0060] Furthermore, it is preferable that the distance between crosslinking points of the soft segment be as uniform as possible. If the distance between crosslinking points is uneven, variations are likely to occur in the molecular motion of the entire elastic member. For example In some cases, E'(2) may decrease due to some components with high molecular mobility, and E'(1) may increase due to some components with low molecular mobility. Therefore, in order for E'(1) and E'(2) to satisfy the above-mentioned specific range, it is preferable to have fewer rigid components and more cross-linked structures, while making the distance between cross-linking points uniform. The method for making the distance between cross-linking points uniform is not limited, but one example is to use a prepolymer with a molecular weight distribution that is as uniform as possible and produce polyurethane by the prepolymer method. It is also preferable to use a simple material composition with uniform molecular weights so that the molecular weight distribution is uniform, and it is also preferable to minimize the use of chain extenders such as glycols that tend to make the molecular weight distribution non-uniform. In this case, the number-average molecular weight of the prepolymer is preferably 8000 to 12000. The molecular weight can be analyzed by GPC using the method described above.

[0061] [Support members] The cleaning blade of this disclosure has a support member that supports an elastic member. The material constituting the support member is not particularly limited and may include, for example, the following materials: metallic materials such as steel plates, stainless steel plates, galvanized steel plates, and chromium-free steel plates; and resin materials such as 6-nylon and 6,6-nylon. Furthermore, the shape and structure of the support member are not particularly limited. For example, the elastic member of the cleaning blade is supported at one end by a support member, as shown in Figure 2.

[0062] [Elastic material] The elastic component contains polyurethane. Specifically, it contains polyurethane elastomer. The polyurethane elastomer constituting the elastic component is mainly obtained from raw materials such as polyols, chain extenders, crosslinking agents, polyisocyanates, catalysts, and other additives. These raw materials are described in detail below.

[0063] Examples of polyols include: polyester polyols such as polyethylene adipate polyol, polybutylene adipate polyol, polyhexylene adipate polyol, (polyethylene / polypropylene) adipate polyol, (polyethylene / polybutylene) adipate polyol, and (polyethylene / polyneopentylene) adipate polyol; polycaprolactone-based polyols obtained by ring-opening polymerization of caprolactone; polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; and polycarbonate diols. These can be used individually or in combination of two or more. Among the polyols mentioned above, polyester polyols using adipate are preferred because they yield polyurethane elastomers with excellent mechanical properties. Polyester polyols using butylene adipate are even more preferred.

[0064] As the chain extender mentioned above, glycols capable of extending polyurethane elastomer chains, polyhydric alcohols of trivalent or higher valency, etc., can be used. Examples of glycols include: ethylene glycol (EG), diethylene glycol (DEG), propylene glycol (PG), dipropylene glycol (DPG), 1,4-butanediol (1,4-BD), 1,6-hexanediol (1,6-HD), 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, xylylene glycol (terephthalyl alcohol), and triethylene glycol. Examples of polyhydric alcohols with a valency of 3 or higher include trimethylolpropane, glycerin, pentaerythritol, and sorbitol. These can be used individually or in combination of two or more. It is preferable to use these polyhydric alcohols with a valency of 3 or higher as crosslinking agents. Among the above polyhydric alcohols, trimethylolpropane is more preferred.

[0065] Examples of the above polyisocyanates include: 4,4'-diphenylmethane diisocyanate (4,4'-MDI), polymeric MDI, 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), xylene diisocyanate (XDI), 1,5-naphthylene diisocyanate (1,5-NDI), p-phenylene diisocyanate (PPDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), tetramethylxylene diisocyanate (TMXDI), and carbodiimide-modified MDI. Among the above polyisocyanates, 4,4'-MDI is preferred because it is highly reactive and its two isocyanate groups have equivalent reactivity.

[0066] As the catalysts mentioned above, catalysts commonly used for curing polyurethane elastomers can be used. For example, tertiary amine catalysts can be used, and specifically, the following can be cited: amino alcohols such as dimethylethanolamine, N,N,N'-trimethylaminopropylethanolamine, and N,N'-dimethylhexanolamine; trialkylamines such as triethylamine; tetraalkyldiamines such as N,N,N'N'-tetramethyl-1,3-butanediamine; triethylenediamine, piperazine compounds, and triazine compounds. In addition, metal organic salts such as potassium acetate and potassium alkali octate can also be used. Furthermore, metal catalysts commonly used for urethane formation, such as dibutyltin dilaurate, can also be used. These can be used individually or in combination of two or more.

[0067] As a catalyst, N,N'-dimethylhexanolamine is preferred. A commercially available example is Kaolizer No. 25 (trade name), manufactured by Kao Corporation. This catalyst is suitable for prioritizing urethane formation over nurating formation. Furthermore, it has an OH group at its terminal end, and while acting as a catalyst, it also reacts and is incorporated into the structure, thus reducing the possibility of chemical attack due to leaching. In addition, it is preferred because of its good reactivity. A potassium acetate ethylene glycol solution is also preferred. A commercially available example is POLYCAT46 (trade name) (manufactured by Air Products Japan Co., Ltd.).

[0068] For example, the polyurethane elastomer is preferably a cured product of a mixture containing at least one polyol selected from the group consisting of polyester polyols and polyether polyols, a polyhydric alcohol of trivalent or higher, and at least 4,4'-MDI. For example, the polyurethane elastomer is preferably a cured product of a mixture containing at least one polyol selected from the group consisting of polyester polyols and polyether polyols, a polyisocyanate containing 4,4'-MDI, and a polyhydric alcohol of trivalent or higher. In the mixture used as a raw material for polyurethane elastomers, the polyol content is preferably 50 to 80% by mass, and more preferably 55 to 70% by mass. Among the components of the mixture used as a raw material for polyurethane elastomer, the content of polyisocyanate is preferably 15 to 50% by mass, and more preferably 25 to 40% by mass. In the mixture used as a raw material for polyurethane elastomers, the content of trivalent or higher polyhydric alcohols is preferably 3 to 15% by mass, and more preferably 5 to 10% by mass.

[0069] The raw materials that make up the elastic material may contain additives such as pigments, plasticizers, waterproofing agents, antioxidants, UV absorbers, and light stabilizers, as needed.

[0070] <How to manufacture a cleaning blade> The method for manufacturing a cleaning blade relating to this disclosure is not particularly limited and may include known methods. Then you can choose the one that is most suitable. The method for producing an elastic member containing a polyurethane elastomer is not particularly limited, but it is preferable to include the following steps, for example. The polyurethane elastomer composition is preferably produced by a prepolymerization method using a prepolymer with a molecular weight distribution as uniform as possible. First, it is preferable to have a step of reacting a polyol with a polyisocyanate to obtain a prepolymer. The NCO content in the prepolymer is not particularly limited, but is preferably 3.00 to 15.00% by mass, and more preferably 6.00 to 10.00% by mass.

[0071] Next, a mixture of a crosslinking agent and a catalyst (curing agent) is added to the obtained prepolymer and mixed to obtain a polyurethane elastomer composition. A polyol may also be added to the curing agent. From the viewpoint of ensuring uniform crosslinking point distances, it is preferable that the number-average molecular weight of the polyol added to the curing agent be the same as the number-average molecular weight of the polyol used in the prepolymer. For example, it is preferable that the difference in the number-average molecular weights of the two is 500 or less, 200 or less, or 100 or less.

[0072] After placing the support member in the mold for forming the cleaning blade, the polyurethane elastomer composition is injected into the cavity and heated to cure, thereby obtaining a cleaning blade in which the plate-shaped blade member and the support member are integrated. A known release agent may be applied to the mold. Alternatively, a polyurethane elastomer sheet can be separately molded from the above polyurethane raw material composition, cut into strips to prepare elastic members, and the adhesive portion of the elastic members can be placed on top of a support member to which an adhesive has been applied or attached, and then heated and pressed to bond them together.

[0073] <Process cartridges and electrophotographic image forming apparatus> The cleaning blade can be incorporated into a process cartridge that is detachably configured for use in an electrophotographic image forming apparatus. Specifically, for example, in a process cartridge comprising an image carrier as a member to be cleaned and a cleaning blade positioned to clean the surface of the image carrier, the cleaning blade according to this embodiment can be used as the cleaning blade. The above-mentioned process cartridge contributes to the stable formation of high-quality electrophotographs.

[0074] Furthermore, an electrophotographic image forming apparatus according to one aspect of the present invention comprises an image carrier such as a photoreceptor and a cleaning blade arranged to clean the surface of the image carrier, wherein the cleaning blade is the cleaning blade according to this aspect. The above-described electrophotographic image forming apparatus is capable of stably forming high-quality electrophotographic images. [Examples]

[0075] The present invention will be described below with reference to manufacturing examples, examples, and comparative examples, but this disclosure is not limited in any way by these examples. In the examples and comparative examples, raw materials other than those indicated were reagents or industrial chemicals.

[0076] In the following examples and comparative examples, the integrally molded cleaning blade shown in Figure 1 was manufactured and evaluated. The formulations, physical properties of the obtained elastic members, and evaluation results for each example and comparative example are shown in Tables 1 and 2.

[0077] <Example 1> [Support members] A 1.6 mm thick galvanized steel sheet was prepared and processed to obtain a support member with an L-shaped cross-section, as indicated by reference numeral 3 in Figure 2. Furthermore, a single-layer urethane-metal adhesive (product name: Chemlock 219, manufactured by Road Corporation) was applied to the areas of the support member that come into contact with the elastic member.

[0078] [Preparation of raw materials for elastic components] (Prepolymer) • As an isocyanate, 4,4'-diphenylmethane diisocyanate (product name: Myrionate MT, manufactured by Tosoh Corporation) (hereinafter referred to as 4,4'-MDI) 327.0g • As a polyol, 673.0g of butylene adipate polyester polyol with a number average molecular weight of 2500 (product name: Nipponran 3027, manufactured by Tosoh Corporation) (hereinafter referred to as PBA2500) The above materials were reacted at 80°C for 3 hours to obtain a prepolymer with an NCO content of 8.80% by mass.

[0079] (Hardening agent) Trimethylolpropane (manufactured by Tokyo Chemical Industry Co., Ltd.) (hereinafter referred to as TMP) 84.3g • N,N'-dimethylhexanolamine (product name: Kaolizer No. 25, manufactured by Kao Corporation) (hereinafter referred to as No. 25) 0.25g The above materials were mixed to prepare a hardening agent.

[0080] A polyurethane elastomer composition was obtained by mixing a curing agent with the resulting prepolymer. The adhesive-coated portion of the support member was positioned to protrude into the cavity of the mold for the cleaning blade. A polyurethane elastomer composition was injected into the mold for the cleaning blade, cured at 130°C for 5 minutes, and then demolded to obtain an integral molded body of polyurethane and the support member.

[0081] The mold used was coated with release agent A before injecting the polyurethane elastomer composition. Release agent A was a mixture of ELEMENT14 PDMS 1000-JC 5.06g (product name, manufactured by Momentive Performance Materials), ELEMENT14 PDMS 10K-JC 6.19g (product name, manufactured by Momentive Performance Materials), SR1000 3.75g (product name, manufactured by Momentive Performance Materials), and EXXSOL DSP145 / 160 85g.

[0082] The tip end of this integrally molded polyurethane elastomer was appropriately cut to obtain a plate-shaped elastic member having a main surface and a tip surface that together with the main surface constitutes the tip edge. The angle of the tip edge was set to 90 degrees, and the distances in the short, thickness, and longitudinal directions of the elastic member were set to 7.5 mm, 1.8 mm, and 240 mm, respectively. The obtained cleaning blades were evaluated using the following method.

[0083] [Method for calculating the storage modulus] The storage moduli E'(1) and E'(2) of the elastic members were measured using a dynamic viscoelastic device with temperature-frequency dispersion, and a master curve was created and calculated at a reference temperature of 8°C based on the temperature-time conversion rule. The obtained master curve is shown in Figure 5.

[0084] The measurement conditions for dynamic viscoelasticity are described below. Equipment: Dynamic viscoelasticity measuring device (product name: DMA EXPLEXOR 500N, manufactured by NETZSCH) Measurement mode: Pull Static distortion: 2% Dynamic distortion: 0.5% Measurement temperature: -30℃ to 80℃ (2℃ increments, 56 points) Measurement frequency: 0.1~100Hz (5 points)

[0085] Based on the obtained dynamic viscoelasticity measurement results, a master curve at a reference temperature of 8°C was created using the in-device software. From the obtained master curve, a mathematical approximation was performed based on the generalized Maxwell model. The generalized Maxwell model is as follows:

number

[0086] When the above generalized Maxwell model is separated into the storage modulus E' and the loss modulus E'', it becomes as follows.

number

[0087] In mathematical approximations, the number of terms in the generalized Maxwell model is the elastic term (E e )1 + viscoelastic term (E i )20 (i=1~20). τi is 10 ―8 ~10 5 Twenty points were arbitrarily selected within that range. The GRG nonlinear (generalized reduced gradient method) is used to minimize the difference between E' and E'' in the generalized Maxwell model and E' and E'' in the master curve. e and E i We optimized it. Specifically, we used Excel's Solver function. From the obtained master curve approximation formula, E'(1)(1×10 ―3 E') and E'(2)(1 × 10⁻¹⁰ Hz 4 We obtained E' at Hz.

[0088] The sample for measurement was prepared as follows. Samples were prepared to include the corners (e.g., the tip edge) of the elastic member at the contact point with the member to be cleaned. They were cut into strips 50 mm long, 2 mm wide, and 1.8 mm thick.

[0089] [Measurement of T2 relaxation time] The spin-spin relaxation time (T2) was measured using the solid echo method in pulsed NMR analysis. For the sample, the elastic component of the cleaning blade was cut from the measurement position described later, and then finely chopped into pieces measuring 1 mm x 1 mm. 1 g of these pieces was then prepared in a test tube.

[0090] The measurement conditions for pulsed NMR are described below. Equipment: JNM-MU25 (manufactured by JEOL) Condition: Solid echo method Measurement environment: 50℃ Number of measurements: 128 The measurement results are separated into two components (soft segment and hard segment) using the least squares method in the instrument's software, and the spin-spin relaxation time (T2) of each component is calculated.L and T2 S ) was obtained. In this disclosure, the obtained T2 relaxation curve is divided into hard segments and according to the length of the relaxation time. The soft segment is separated into two components. Specifically, the T2 relaxation curve is curve-fitted to the following equation to separate it into two components, the hard segment and the soft segment, and the spin-spin relaxation time (T2) of the soft segment is calculated. L ), hard segment spin-spin relaxation time (T2 S Calculate ).

number

[0091] [FT-IR analysis of elastic members using the ATR method] 1415cm of the elastic member -1 The peak intensity and 1538 cm -1 The peak intensity values ​​were measured using the ATR method with FT-IR. The sample used was an elastic component of a cleaning blade, cut from the measurement location described later.

[0092] The measurement conditions for FT-IR are described below. Equipment: FT / IR-4700 (manufactured by JASCO) Measurement mode: ATR method (crystal: diamond) Total number of times: 64 Measurement locations: The length of the tip edge of the cleaning blade was defined as L, and measurements were taken at positions 1 / 8L, 1 / 2L, and 7 / 8L from one end of the edge. From the obtained peak intensity, 1415 cm -1 Peak intensity / 1538cm -1 The peak intensity values ​​were calculated, and their arithmetic mean values ​​are shown in Table 1.

[0093] [Measurement methods for M1 and M2] Measurements of M1 and M2 were performed using the direct sample introduction method (DI method), in which the sample was introduced directly into the ion source without passing through a gas chromatograph (GC). The apparatus used was a POLARIS Q manufactured by Thermo Fisher Scientific K.K., employing a Direct Exposure Probe (DEP). Assuming that a line segment is drawn parallel to the tip edge of the elastic member, with a distance of 0.5 mm from the tip edge, the length of the line segment is denoted as L', and points P0', P1', and P2' are designated as 1 / 8L', 1 / 2L', and 7 / 8L' from one end of the line segment, respectively. Polyurethane was then scraped off from P0', P1', and P2' using a bio-cutter.

[0094] A 0.1 μg sample was attached to a filament located at the tip of the probe at each of points P0', P1', and P2', and inserted directly into the ionization chamber. The chamber was then rapidly heated from room temperature to 1000°C at a constant heating rate (10°C / s), and the vaporized gas was detected by a mass spectrometer. The detection amount M1 for all ions was calculated by summing the integrated intensities of all peaks in the obtained total ion current thermogram. M2 was defined as the integrated intensity of the peaks in the extracted ion thermogram corresponding to m / z values ​​in the range of 380.5 to 381.5, derived from polymeric MDI, and M2 / M1 was calculated. The arithmetic mean of the numerical values ​​obtained in each of P0', P1', and P2' was used as the value of M2 / M1 in this disclosure.

[0095] [Nip width evaluation] As shown in Figure 3, the elastic member 2 of the cleaning blade 1 was brought into contact with a glass 8 coated with an anti-reflective film. While moving the glass in the direction indicated by arrow 10, the contact point (nip) between the glass and the elastic member of the cleaning blade was observed using a laser microscope 9, and the nip width was measured by analyzing the obtained images with image analysis software (Image-Pro Plus). Observation: Laser microscope Glass movement speed: 10 mm / s Penetration amount: 0.8mm Setting angle: 25° Measurement location: The length of the tip edge of the cleaning blade was defined as L, and the nip width was measured at positions 1 / 8L, 1 / 2L, and 7 / 8L from one end of the edge. Because light is blocked at the contact point, it appears black when observed with a laser microscope. This allows for the identification of the contact and non-contact points and measurement of their width. The average value of the measurement results at the above measurement position was evaluated as the nip width. The results are shown in Table 1.

[0096] [Stick-Slip Evaluation] As shown in Figure 4, the photoreceptor 6, which is the member to be cleaned, was brought into contact with the elastic member 2 of the cleaning blade 1. The photoreceptor 6 was rotated in the direction indicated by arrow 7, and the displacement of the contact point was measured by a laser displacement meter 11. The amount of displacement of the contact point was evaluated as the stick-slip width. The measurement conditions were as follows. An electrophotographic photosensitive drum with a diameter of 24 mm and a surface layer containing polyarylate resin was used as the photoreceptor. • Cleaning blade penetration depth: 0.8mm • Setting angle: 25 degrees • Rotation speed of the electrophotographic drum: 150 rpm When stick-slip occurs, the distance from the laser displacement meter 11 to the contact point between the elastic member 2 of the cleaning blade 1 and the photoreceptor 6 changes, allowing the laser displacement meter to evaluate the stick-slip width. Equipment: Laser displacement meter (LJV-7000, manufactured by Keyence Corporation) Sampling frequency: 64kHz Number of measurement points: 10,000 Measurement location: The length of the tip edge of the cleaning blade was defined as L, and the stick-slip width was measured at positions 1 / 8L, 1 / 2L, and 7 / 8L from one end of the edge. The average value of the measurement results at the above measurement locations was evaluated as the stick-slip width. The results are shown in Table 1.

[0097] <Evaluation of cleaning performance> The cleaning blade obtained by the method described above was incorporated into the cyan cartridge of a color laser beam printer (product name: HP LaserJet Enterprise Color M554dn, manufactured by HP) as a cleaning blade for the photoreceptor, which is the component to be cleaned. In addition, the toner in the developer of the cyan cartridge was completely replaced with toner 1, which will be described later. Next, the samples were left in a low-temperature environment (8°C) for 24 hours, and then 10,000 images were formed under the same conditions. Furthermore, the developing machine used was replaced with a separate developing machine equipped with a new cyan cartridge, and another 10,000 images were processed. This process was repeated, resulting in a total of 150,000 images being processed. Every 50,000 images, a halftone image was output as an evaluation image, and a cleaning brake was applied. We visually inspected the image for any defects (streaks on the image) caused by the image sensor and performed an image evaluation. The cleaning performance was evaluated by ranking the products according to the following evaluation criteria. The results are shown in Table 1. Rank A: No image defects occur after 150,000 image formations. Rank B: Image defects occurred after 100,000 image formations. Rank C: Image defects occurred after 50,000 image formations. Rank D: Image defects occurred before 50,000 images had been formed.

[0098] <Manufacturing method for toner 1> In the following, unless otherwise specified, "part" refers to a mass-based unit. (Preparation process for aqueous medium 1) 650.0 parts of deionized water were added to a reaction vessel equipped with a stirrer, thermometer, and reflux tubing, and 14.0 parts of sodium phosphate (decadohydrate, manufactured by Rasa Industries Co., Ltd.) were added. The mixture was then kept warm at 65°C for 1.0 hour while purging with nitrogen. Using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), a calcium chloride aqueous solution, prepared by dissolving 9.2 parts of calcium chloride (dihydrate) in 10.0 parts of deionized water, was added all at once while stirring at 15,000 rpm to prepare an aqueous medium containing a dispersion stabilizer. Furthermore, 10% by mass hydrochloric acid was added to the aqueous medium to adjust the pH to 5.0 to obtain aqueous medium 1.

[0099] (Preparation process for polymerizable monomer composition) • Styrene: 60.0 parts CI Pigment Blue 15:3 : 6.5 parts The aforementioned materials were placed in an attritor (manufactured by Mitsui Miike Chemical Machinery Co., Ltd.), and further dispersed using 1.7 mm diameter zirconia particles 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 (Polycondensate of propylene oxide-modified bisphenol A (2 molar adduct) and terephthalic acid (molar ratio 10:12), glass transition temperature Tg = 68°C, weight-average molecular weight Mw = 10000, molecular weight distribution Mw / Mn = 5.12) Fischer-Tropsch wax (melting point 78°C): 7.0 parts This was kept warm 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.

[0100] (granulation process) While maintaining the temperature of aqueous medium 1 at 70°C and the rotation speed of the TK homomixer at 15,000 rpm, a polymerizable monomer composition was added to aqueous medium 1, and 10.0 parts of t-butyl peroxypivalate, a polymerization initiator, were added. Granulation was then carried out for 10 minutes while maintaining a stirring speed of 15,000 rpm with the same stirring device.

[0101] (Polymerization and distillation process) After the granulation process, the stirrer was replaced with a propeller-type stirring blade, and polymerization was carried out for 5.0 hours while stirring at 150 rpm and maintaining a temperature of 70°C. The polymerization reaction was then carried out by raising the temperature to 85°C and heating for 2.0 hours. Subsequently, the reflux tubing of the reaction vessel was replaced with a condenser, and the slurry was heated to 100°C. Distillation was carried out for 6 hours to remove unreacted polymerizable monomers, yielding a toner mother particle dispersion.

[0102] (Polymerization of organosilicon compounds) 60.0 parts of deionized water were weighed into a reaction vessel equipped with a stirrer and thermometer, and the pH was adjusted to 4.0 using 10% by mass hydrochloric acid. This was heated while stirring until the temperature reached 40°C. Subsequently, 40.0 parts of methyltriethoxysilane, an organosilicon compound, were added and the mixture was stirred for more than 2 hours to carry out hydrolysis. The endpoint of hydrolysis was confirmed by visual inspection when the oil and water no longer separated into a single layer, and the mixture was cooled to obtain the hydrolyzed solution of the organosilicon compound. The obtained toner mother particle dispersion was cooled to 55°C, and then 25.0 parts of hydrolyzed organosilicon compound solution were added to initiate polymerization of the organosilicon compound. After holding for 15 minutes, the pH was adjusted to 5.5 with a 3.0% by mass sodium bicarbonate aqueous solution. The mixture was held at 55°C for 60 minutes while stirring was continued, then the pH was adjusted to 9.5 with a 3.0% by mass sodium bicarbonate aqueous solution, and the mixture was held for a further 240 minutes to obtain the toner particle dispersion.

[0103] (Washing and drying process) After the polymerization process was completed, the toner particle dispersion was cooled, hydrochloric acid was added to adjust the pH to 1.5 or lower, and the mixture was stirred and left for 1 hour before solid-liquid separation was performed using a pressure filter to obtain the toner cake. This was then re-slurred with deionized water to obtain another dispersion, and solid-liquid separation was performed using the aforementioned filter to obtain the toner cake again. The resulting toner cake was dried and classified in a constant temperature bath at 40°C for 72 hours to obtain toner 1.

[0104] <Examples 2-10 and Comparative Examples 1-7> As shown in Tables 1 and 2, a prepolymer and curing agent were prepared in the same manner as in Example 1, except that the materials and quantities of the formulation were changed, to obtain a polyurethane elastomer composition. A cleaning blade was made using the obtained polyurethane elastomer composition, and the obtained cleaning blade was evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 1 and 2. Furthermore, Figure 5 shows the master curve for the elastic member related to Comparative Example 1, showing the relationship between the storage modulus (E') and the measurement frequency obtained in the same manner as in Example 1.

[0105] Details of the materials used other than those shown in Example 1 are shown below. Polybutylene adipate polyester polyol with a number-average molecular weight of 1000 (product name: Nipponran 4009, manufactured by Tosoh Corporation) (hereinafter referred to as PBA1000). Polybutylene adipate polyester polyol with a number-average molecular weight of 2000 (product name: Nipponran 4010, manufactured by Tosoh Corporation) (hereinafter referred to as PBA2000). Polyhexylene adipate polyester polyol with a number-average molecular weight of 2600 (product name: Nipponran 136, manufactured by Tosoh Corporation) (hereinafter referred to as PHA2600). Polyhexylene adipate polyester polyol with a number-average molecular weight of 1000 (product name: Nipponran 164, manufactured by Tosoh Corporation) (hereinafter referred to as PHA1000). Polytetramethylene ether glycol with a number-average molecular weight of 1000 (product name: PTG-1000SN, manufactured by Hodogaya Chemical Co., Ltd.) (hereinafter referred to as PTMG1000). Polymeric MDI (product name: Millionate MR-400, manufactured by Tosoh Corporation) (hereinafter referred to as pMDI). 1,4-Butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) (hereinafter referred to as 1,4-BD) POLYCAT46 (manufactured by Air Products Japan Co., Ltd.) (hereinafter referred to as PC46) TOYOCAT-RX5 (manufactured by Tosoh Corporation) (hereinafter referred to as RX5) TEDA (triethylenediamine) (manufactured by Tosoh Corporation) K-KAT XK-627 (manufactured by Kusumoto Kasei) (hereinafter referred to as K-KAT) [Table 1] [Table 2]

[0106] This disclosure relates to the following configuration. (Composition 1) It comprises an elastic member containing polyurethane and a support member that supports the elastic member, An electrophotographic cleaning blade that cleans the surface of a moving member to be cleaned by bringing a part of the elastic member into contact with the surface of the member to be cleaned, In an 8°C environment, the vibration frequency of the elastic member is 1 × 10⁻⁶. -3 Let E'(1) be the storage modulus at Hz, and the vibration frequency be 1 × 10⁻⁶. 4 When the storage modulus at Hz is E'(2), E'(1) is 12.0~18.0 MPa, An electrophotographic cleaning blade characterized in that E'(2) is 530.0 to 1500.0 MPa. (Configuration 2) The polyurethane is a polyurethane elastomer consisting of a hard segment and a soft segment. In pulsed NMR measurements at a 50°C environment, when the hard segment and the soft segment are separated into two components, the spin-spin relaxation time (T2) of the soft segment is measured. LThe electrophotographic cleaning blade described in Configuration 1 has a pulse duration of 250-320 μs. (Composition 3) In the FT-IR measurement of the elastic member using diamond as the ATR crystal, 1415 cm -1 The peak intensity was 1538 cm. -1 An electrophotographic cleaning blade according to configuration 1 or 2, wherein the ratio value of to the peak intensity is 0.50 to 0.65. (Composition 4) When the side of the electrophotographic cleaning blade that contacts the surface of the member to be cleaned is defined as the tip side of the electrophotographic cleaning blade, The elastic member has a plate shape, at least at the tip end, having a main surface that faces the member to be cleaned and a tip surface that together with the main surface forms the tip edge. Assuming that a third line segment is drawn on the tip surface parallel to the tip edge, with a distance of 0.5 mm from the tip edge, Let the length of the third line segment be L'. Let P0', P1', and P2' be the points 1 / 8L', 1 / 2L', and 7 / 8L' from one end of the third line segment, respectively. The sample sampled at each of P0', P1', and P2' is heated and vaporized in an ionization chamber, and the sample molecules are ionized using a direct sample introduction type mass spectrometer, which is heated to 1000°C at a heating rate of 10°C / s. Let M1 be the total amount of ions detected. When M2 is defined as the integrated intensity of the peaks in the extracted ion thermogram corresponding to m / z values ​​in the range of 380.5 to 381.5, derived from polymeric MDI, An electrophotographic cleaning blade as described in any of configurations 1 to 3, wherein M2 / M1 is less than 0.0010. (Composition 5) A process cartridge having an electrophotographic cleaning blade as described in any of configurations 1 to 4. (Composition 6) An electrophotographic image forming apparatus having an electrophotographic cleaning blade as described in any of configurations 1 to 5. [Explanation of Symbols]

[0107] 1 Cleaning blade, 2 Elastic member, 3 Support member, 4 Main surface facing the member to be cleaned, 5 Tip surface forming the tip edge together with the main surface, 6 Member to be cleaned, 7 Rotational direction of the member to be cleaned, 8 Glass, 9 Laser microscope, 10 Direction of movement of the glass, 11 Laser displacement meter

Claims

1. It comprises an elastic member containing polyurethane and a support member that supports the elastic member, An electrophotographic cleaning blade that cleans the surface of a moving member to be cleaned by bringing a part of the elastic member into contact with the surface of the member to be cleaned, In an 8°C environment, the vibration frequency of the elastic member is 1 × 10⁻⁶. －３ Let E'(1) be the storage modulus at Hz, and the vibration frequency be 1 × 10⁻⁶. ４ When the storage modulus at Hz is E'(2), E'(1) is 12.0 to 18.0 MPa, An electrophotographic cleaning blade characterized in that E'(2) is 530.0 to 1500.0 MPa.

2. The polyurethane is a polyurethane elastomer consisting of a hard segment and a soft segment. In pulsed NMR measurements in a 50°C environment, when the hard segment and the soft segment are separated into two components, the spin-spin relaxation time (T2) of the soft segment is measured. Ｌ The electrophotographic cleaning blade according to claim 1, wherein the interval is 250 to 320 μs.

3. In the FT-IR measurement of the elastic member using diamond as the ATR crystal, 1415 cm⁻¹ －１ The peak intensity was 1538 cm². －１ The electrophotographic cleaning blade according to claim 2, wherein the ratio value to the peak intensity is 0.50 to 0.

65.

4. When the side of the electrophotographic cleaning blade that contacts the surface of the member to be cleaned is defined as the tip side of the electrophotographic cleaning blade, The elastic member has a plate shape, at least at the tip end, having a main surface that faces the member to be cleaned and a tip surface that together with the main surface forms the tip edge. Assuming that a third line segment is drawn on the tip surface parallel to the tip edge, with a distance of 0.5 mm from the tip edge, Let the length of the third line segment be L'. Let P0', P1', and P2' be points 1 / 8L', 1 / 2L', and 7 / 8L' from one end of the third line segment, respectively. The sample sampled at each of P0', P1', and P2' is heated and vaporized in an ionization chamber, and the sample molecules are ionized using a direct sample introduction type mass spectrometer, which is heated to 1000°C at a heating rate of 10°C / s. Let M1 be the total amount of ions detected. When M2 is defined as the integrated intensity of the peaks in the extracted ion thermogram corresponding to m / z values ​​in the range of 380.5 to 381.5, derived from polymeric MDI, The electrophotographic cleaning blade according to claim 3, wherein M2 / M1 is less than 0.0010.

5. A process cartridge having an electrophotographic cleaning blade according to any one of claims 1 to 4.

6. An electrophotographic image forming apparatus having an electrophotographic cleaning blade according to any one of claims 1 to 4.

Images