Electrophotographic cleaning blade, process cartridge, electrophotographic image forming apparatus, and urethane molded body

Abstract

The invention relates to an electrophotographic cleaning blade, a process cartridge, an electrophotographic image forming apparatus, and a urethane molded body. An electrophotographic cleaning blade includes an elastic member including polyurethane and a support member supporting the elastic member, in which the elastic member has a storage elastic modulus of 12.0 to 18.0 MPa at a vibration frequency of 1 * 10 <-3 > Hz, a segment having a spin-spin relaxation time (T2L) of 250 to 360 [mu] s is present in a pulsed NMR measurement of a sample sampled from the elastic member in an environment of 50 DEG C, and the support member is configured to support the elastic member. The polyurethane includes a polyurethane elastomer including a polysiloxane segment having a specific structure, and the polysiloxane segment is bonded to a polyurethane backbone in the polyurethane elastomer.

Description

Technical Field

[0001] This disclosure relates to cleaning blades, processing cartridges, image forming apparatus, and urethane molded products used in electrophotographic devices. Background Technology

[0002] In electrophotographic devices, cleaning components are provided to remove residual toner from the surfaces of the image carrier or intermediate transfer member after the toner image has been transferred from an image carrier member (e.g., a photosensitive member) and an intermediate transfer member to a target transfer member. Hereinafter, the image carrier member and intermediate transfer member are referred to as the to-be-cleaned member. One of these cleaning components is a cleaning scraper.

[0003] In recent years, with the increase in the number of printable pages due to the extended lifespan of electrophotographic devices, there has been a demand for cleaning blades that can maintain a high level of cleaning performance over a long period. To extend lifespan, it is necessary to reduce the grinding of the portion of the photosensitive drum (the component being cleaned) that comes into contact with the cleaning blade.

[0004] In this regard, Japanese Patent Application Publication No. H07-098558 discloses that using a soft cleaning scraper with a hardness below a certain value can reduce the abrasion of the photosensitive drum. Summary of the Invention

[0005] However, in recent years, toners have become spherical and processing speeds have increased, which may lead to poor cleaning with soft cleaning blades. With this in mind, it is advisable to set the hardness of the cleaning blade to a level that is low enough to reduce the grinding of the photosensitive drum but high enough to prevent toner from slipping.

[0006] Furthermore, the elastic components constituting the cleaning scraper may lose hardness due to moisture absorption in high-humidity environments. Therefore, the hardness of the cleaning scraper needs to be controlled as described above, and the design must take into account the hardness reduction caused by moisture absorption, resulting in a narrow range of usable hardness. Consequently, it is difficult to simultaneously achieve both excellent cleaning performance and reduced drum grinding to extend service life.

[0007] This disclosure aims to provide a cleaning scraper with a long lifespan and the ability to consistently exhibit excellent cleaning performance in high-speed systems. Specifically, this disclosure aims to provide a cleaning scraper that, by reducing moisture absorption, does not easily lose its hardness even in high humidity environments and exhibits excellent cleaning performance.

[0008] Furthermore, this disclosure aims to provide a processing cartridge including a cleaning scraper. Therefore, it can help extend the cartridge's lifespan. Additionally, this disclosure aims to provide an electrophotographic image forming apparatus including a cleaning scraper. Furthermore, this disclosure aims to provide a urethane molded article that is not prone to moisture absorption and exhibits minimal hardness change due to humidity variations.

[0009] According to at least one aspect of this disclosure, an electrophotographic cleaning squeegee is provided, comprising:

[0010] Elastic components containing polyurethane, and

[0011] Supporting members for elastic members

[0012] Electrophotographic cleaning squeegees clean the surface of a component by bringing a portion of a resilient member into contact with the surface of the component being cleaned while it is moving.

[0013] In an environment of 24℃, the elastic component exhibits a strength of 1×10⁻⁶. -3 The storage modulus of elasticity at vibration frequencies of Hz is 12.0 to 18.0 MPa.

[0014] In pulsed NMR measurements of samples taken from elastic members at 50°C, a spin-spin relaxation time (T2) exists. L The segments are 250 to 360 μs long.

[0015] Polyurethane includes polyurethane elastomers.

[0016] Polyurethane elastomers comprise polysiloxane segments having a structure represented by formula (1).

[0017] The polysiloxane segments are bonded to the polyurethane elastomer containing a polyurethane backbone, and

[0018] The number I of structures represented by formula (1) for each polysiloxane segment is between 7 and 195:

[0019]

[0020] According to at least one aspect of this disclosure, a processing box is provided that includes the above-described electrophotographic cleaning squeegee and the component to be cleaned.

[0021] In addition, according to at least one aspect of this disclosure, an electrophotographic image forming apparatus is provided, comprising the above-described electrophotographic cleaning squeegee and the component to be cleaned.

[0022] According to at least one aspect of this disclosure, a urethane molded article comprising polyurethane is provided.

[0023] Among them, in an environment of 24℃, polyurethane has a strength of 1×10⁻⁶. -3 The storage modulus of elasticity at vibration frequencies of Hz is 12.0 to 18.0 MPa.

[0024] In pulsed NMR measurements of samples taken from urethane molded bodies at 50°C, a spin-spin relaxation time (T2) was observed. L The segments are 250 to 360 μs long.

[0025] Polyurethane includes polyurethane elastomers.

[0026] Polyurethane elastomers comprise polysiloxane segments having a structure represented by formula (1).

[0027] The polysiloxane segments are bonded to the polyurethane elastomer containing a polyurethane backbone, and

[0028] The number I of structures represented by formula (1) for each polysiloxane segment is between 7 and 195:

[0029]

[0030] According to one aspect of this disclosure, a cleaning scraper can be provided that does not easily lose hardness even in high humidity environments by reducing moisture absorption and has excellent cleaning performance. Additionally, according to another aspect of this disclosure, a urethane molded article that does not easily absorb moisture and exhibits minimal hardness change due to variations in humidity can be provided.

[0031] In addition, according to another aspect of this disclosure, a processing box including the cleaning scraper and an electrophotographic image forming apparatus may be provided.

[0032] Referring to the accompanying drawings, the features of this disclosure will become apparent from the following description of the embodiments. The following description of the embodiments is given by way of example. Attached Figure Description

[0033] Figure 1 This is a schematic perspective view of an electrophotographic cleaning scraper according to one aspect of this disclosure.

[0034] Figure 2 This is a diagram showing the state in which the edge of the cleaning scraper contacts the component being cleaned when the treatment box is stationary. Detailed Implementation

[0035] In this disclosure, unless otherwise stated, the expressions "from XX to YY" or "XX to (~)YY" indicating a numerical range mean a numerical range that includes both the lower and upper limits as endpoints. Furthermore, when a numerical range is described in a stepped manner, the upper and lower limits of each numerical range can be arbitrarily combined.

[0036] Examples of components to be cleaned using an electrophotographic cleaning blade (hereinafter referred to as "cleaning blade") according to one aspect of this disclosure include, for example, image-bearing components such as photosensitive components and annular belts such as intermediate transfer belts. Hereinafter, embodiments of the cleaning blade according to one aspect of this disclosure are described in detail using an image-bearing component as the component to be cleaned, but this disclosure is not limited thereto. Furthermore, in the following description, components having the same function are labeled with the same reference numerals in the drawings, and in some cases, their description is omitted.

[0037] Composition of a cleaning scraper

[0038] The cleaning squeegee includes an elastic member comprising polyurethane and a support member supporting the elastic member, and the electrophotographic cleaning squeegee cleans the surface of the component being cleaned by bringing a portion of the elastic member into contact with the surface of the component being cleaned in motion. The polyurethane includes a polyurethane elastomer.

[0039] Figure 1 This is a schematic perspective view of a cleaning scraper 1 according to one aspect of the present disclosure. The cleaning scraper 1 includes an elastic member 2 and a support member 3 supporting the elastic member 2.

[0040] Figure 2 This is a schematic cross-sectional view illustrating an example of a cleaning scraper in contact with a member being cleaned according to one aspect of this disclosure. The elastic member 2 has a main surface 4 facing the member being cleaned 6 and a front end surface 5 forming a front end side edge together with the main surface 4. Reference numeral 7 indicates the direction of rotation of the member being cleaned.

[0041] Storage elastic modulus

[0042] In an environment of 24°C, the elastic component constituting the cleaning scraper has a strength of 1×10⁻⁶. -3 The storage elastic modulus at a vibration frequency of Hz is 12.0 to 18.0 MPa. It can be measured using a viscoelastic measuring device according to the following method at a vibration frequency of 1×10⁻⁶ MPa. -3 Storage elastic modulus at a vibration frequency of Hz.

[0043] 1×10 -3 The vibration frequency of Hz corresponds to the frequency at which the gap is formed between the cleaning scraper and the cleaned component, and the storage modulus of elasticity at this frequency is related to the gap width. When the storage modulus of elasticity is set to 12.0 to 18.0 MPa, an appropriate gap can be formed and high cleaning performance can be achieved.

[0044] The elastic member in 1×10 -3 The storage modulus at a vibration frequency of Hz is preferably 12.5 to 17.0 MPa, and more preferably 13.0 to 16.0 MPa.

[0045] Reduce moisture absorption

[0046] In high-humidity environments, the elastic components of a cleaning squeegee may become less rigid due to moisture absorption. This reduced rigidity decreases the contact pressure at the squeegee tip and leads to poor cleaning. Therefore, to minimize poor cleaning, it is important to reduce the reduction in rigidity by minimizing moisture absorption by the elastic components.

[0047] The dense cross-linked structure and the coexistence of bonds between the polyurethane and silicone structures in the elastic member can reduce moisture absorption. In other words, the elastic member has a silicone structure within the dense cross-linked structure of polyurethane.

[0048] When the elastic member has a dense cross-linked structure, the space for moisture to enter can be reduced. Furthermore, the reduced compatibility with moisture due to the bonding between the polyurethane and silicone structures makes it difficult for moisture to enter the elastic member. In this case, the dense cross-linked structure narrows the space inside the urethane ester, and the silicone structure bonded to the polyurethane fills this narrow space, synergistically preventing moisture entry and effectively reducing moisture absorption. For example, the elastic member preferably has a structure in which the dense cross-linked structure and the silicone side chain structure coexist.

[0049] Japanese Patent Application Publication No. 2003-186366 discloses a structure in which a siloxane component is fixed in a urethane elastomer. On the other hand, since this disclosure has a structure in which the crosslinking density of the polyurethane is increased and the polyurethane is bonded to the organosilicon structure, a better moisture absorption reduction effect can be obtained compared with a structure in which the siloxane component is simply fixed.

[0050] Crosslinking density

[0051] The crosslinking density of polyurethane can be controlled by the spin-spin relaxation time (T2). L The spin-spin relaxation time is related to the molecular mobility of polyurethane, and the shorter the spin-spin relaxation time, the lower the molecular mobility. Lower molecular mobility indicates a dense cross-linked structure. Therefore, the cross-linking density of polyurethane can be indirectly measured by the spin-spin relaxation time.

[0052] The T2 relaxation curve (free induction decay curve) is obtained by measuring the spin-spin relaxation time T2 (transverse relaxation time) of the scraper rubber using pulse NMR measurements.

[0053] In this disclosure, in pulsed NMR measurements of samples taken from elastic members at 50°C, there exists a spin-spin relaxation time (T2). L The segments are 250 to 360 μs long.

[0054] That is, the elastic member is formed of a polyurethane elastomer containing polyurethane segments with spin-spin relaxation times of 250 to 360 μs.

[0055] The spin-spin relaxation time T2 is measured using a pulsed NMR apparatus via solid-state echo. Specifically, the T2 relaxation curve is obtained during the pulsed NMR measurement. Based on the length of the relaxation time, the obtained T2 relaxation curve is divided into two components. Specifically, the T2 relaxation curve is divided into two components by curve fitting to the formula described below. In the two separated components, T2... L It is the T2 relaxation time of the component with a long relaxation time, and T2 S It is the T2 relaxation time of the component with a short relaxation time.

[0056] Components with long relaxation times are presumed to correspond to soft segments of polyurethane elastomers. Components with short relaxation times are presumed to correspond to hard segments. Here, in this disclosure, hard segments are components with low molecular mobility at or near the crosslinking points, such as aggregated crystalline components with urethane bonds, isocyanurate bonds, polymeric diphenylmethane diisocyanate (polymeric MDI), and trimethylolpropane. Soft segments, on the other hand, are segments with high molecular mobility between crosslinking points.

[0057] The following describes the measurement of T2 using a pulsed NMR device. L A more specific method.

[0058] The elastic component includes polyurethane. Polyurethane may comprise a polyurethane elastomer composed of hard segments and soft segments.

[0059] If the spin-spin relaxation time (T2) L If the crosslinking density is less than 250 μs, the cleaning scraper loses its flexibility and the contact position with the component being cleaned becomes unstable.

[0060] When T2 exists L When the chain segments are 250 to 360 μs, both reduced moisture absorption due to the dense cross-linked structure and stable contact with the component being cleaned can be achieved simultaneously. If T2 L If the value is below 320 μs, it is preferred because it more effectively reduces moisture absorption.

[0061] That is, in pulsed NMR measurements of samples taken from elastic members at 50°C, preferably, a spin-spin relaxation time (T2) exists. L The chain segment is 250 to 320 μs, and more preferably, T2 exists. L The chain segments are 260 to 300 μs long, and more preferably, T2 is present. L The segments are 270 to 290 μs long.

[0062] Spin-spin relaxation time (T2) of soft chain segments L The concentration of the crosslinking agent in the raw material composition of the elastic member can be controlled within the above range, for example, by increasing the concentration of the crosslinking agent.

[0063] Organosilicon side chains

[0064] Polyurethane elastomers comprise polysiloxane segments having a structure represented by the following formula (1).

[0065]

[0066] Polysiloxane segments having the structure represented by formula (1) are bonded to a polyurethane elastomer containing a polyurethane backbone. The number I of the structure represented by formula (1) for each polysiloxane segment is between 7 and 195.

[0067] In the polysiloxane segment, the structure represented by formula (1) can be continuous, or other siloxane structures can exist therein.

[0068] Examples of bonding between the structure represented by formula (1) and the structure containing the polyurethane backbone include the following structures. In the following structures, R represents a hydrocarbon with 1 to 10 carbon atoms (preferably 1 to 5). The -O- on the left is bonded to the structure represented by formula (1), and "*" indicates the bonding site with the polyurethane backbone.

[0069]

[0070] Polyurethane elastomers may have ends that are not bonded to a structure containing a polyurethane backbone. Examples of ends that are not bonded to a structure containing a polyurethane backbone include the following structure. The -O- on the left is bonded to the structure represented by equation (1).

[0071]

[0072] Additionally, the ends not bonded to the polyurethane backbone may have the following structures containing hydroxyl groups. In these structures, R represents a hydrocarbon with 1 to 10 carbon atoms (preferably 1 to 5). This structure illustrates, for example, the state when both ends are made of methanol-modified silicone oil used in a polysiloxane segment and one end is not bonded to the polyurethane backbone.

[0073]

[0074] When a polyurethane elastomer with a highly cross-linked structure contains polysiloxane segments having a structure represented by formula (1), moisture absorption can be reduced.

[0075] The polyurethane elastomer preferably contains 0.5 to 15% by mass of the structure represented by formula (1). More preferably, the polyurethane elastomer contains 0.8 to 12% by mass, and even more preferably 1 to 10% by mass of the structure represented by formula (1).

[0076] Preferably, the polyurethane elastomer contains 0.5% by mass or more of the structure represented by formula (1) because sufficient moisture reduction effect can be obtained. Additionally, it is preferred that the polyurethane elastomer contains 15% by mass or less of the structure represented by formula (1) because the proportion of polyurethane elastomer in the elastic member can be adequately maintained, and the drum following and abrasion resistance required for the cleaning scraper can be obtained.

[0077] In equation (1), I is an integer from 7 to 195. I is preferably an integer from 40 to 160.

[0078] The polysiloxane segments are preferably bonded to the polyurethane backbone via a structure represented by the following formula (2).

[0079]

[0080] (In equation (2), n is an integer from 1 to 5, and "*" indicates the bonding part with the polyurethane skeleton).

[0081] The number m of the structures represented by formula (2) for each polysiloxane segment is preferably 1 to 10.

[0082] That is, preferably, the structure of formula (2) exists between the structures represented by formula (1), and the polysiloxane segments are bonded to the polyurethane backbone via the structure of formula (2). Here, when m = 1 to 10 and multiple structures of formula (2) exist in the polysiloxane segments, the structure of formula (2) can exist in a block or random manner. For example, the structure represented by formula (1) can be bonded to the left and right sides of the structure represented by formula (2), and the structure of formula (2) can exist continuously.

[0083] The -O- on the left side of the structure represented by equation (2) can be bonded to the Si in the structure represented by equation (1) or the Si in the structure represented by equation (2). The Si in the structure represented by equation (2) can be bonded to the -O- in the structure represented by equation (1) or the -O- in the structure represented by equation (2). The repeating structure of the siloxane can be bonded to both sides of the structure represented by equation (2).

[0084] The polysiloxane segments are bonded to a structure comprising a polyurethane backbone, for example, the structure represented by formula (2). Because this bonding form allows the polydimethylsiloxane segments to insert into the crosslinked structure of the polyurethane elastomer, it can more effectively prevent moisture from entering the polyurethane.

[0085] In equation (2), m is preferably 2 to 10, and n is preferably an integer from 1 to 3.

[0086] Japanese Patent Application Publication No. 2020-024375 discloses a urethane elastomer containing a siloxane component. On the other hand, in this disclosure, when a structure in which a siloxane component is fixed within the urethane elastomer is used, a better moisture-absorbing reduction effect can be obtained.

[0087] When the polysiloxane described later is used as a material for elastic components, a polyurethane elastomer having polysiloxane segments comprising a structure represented by formula (1) can be obtained, wherein the polysiloxane segments are bonded to a structure comprising a polyurethane backbone.

[0088] Various modified silicone oils can be used as polysiloxanes. Among them, methanol-modified silicone oils with primary hydroxyl groups that have high reactivity with isocyanates (described later) and are easily fixed in polyurethane elastomers are preferred.

[0089] There are no particular restrictions on methanol-modified silicone oils, and both end-modified and side-chain modified types can be used.

[0090] For example, when using methanol-modified silicone oil with two ends modified, the structure containing the polyurethane skeleton can be bonded to both ends of the structure represented by formula (1), or the structure containing the polyurethane skeleton can be bonded to only one end.

[0091] Examples of bonding between the structure represented by formula (1) and the structure containing the polyurethane backbone include the following structures. In the following structures, R represents a hydrocarbon with 1 to 10 carbon atoms (preferably 1 to 5). The -O- on the left is bonded to the structure represented by formula (1), and "*" indicates the bonding site with the polyurethane backbone.

[0092]

[0093] On the other hand, examples of structures not bonded to the ends of a structure containing a polyurethane backbone include the following structures.

[0094] The -O- on the left is bonded to the structure represented by equation (1).

[0095]

[0096] Additionally, the ends not bonded to the polyurethane backbone may have the following structures containing hydroxyl groups. In these structures, R represents a hydrocarbon with 1 to 10 carbon atoms (preferably 1 to 5). This structure represents, for example, the state when both ends are made of methanol-modified silicone oil used in a polysiloxane segment, and one end is not bonded to the polyurethane backbone.

[0097]

[0098] When using side-chain modified methanol-modified silicone oil, the structure represented by formula (1) can be bonded to the polyurethane skeleton via the structure represented by formula (2).

[0099] The polysiloxane segments preferably have a polysiloxane forming a urethane structure that includes a structure represented by the following formula (3).

[0100]

[0101] (In equation (3), I and m are the average number of moles added, I is from 7 to 195, m is from 1 to 10, and n is an integer from 1 to 5, representing the siloxane structure represented by (-O-Si(CH3)2-) and the siloxane structure represented by (-O-Si(CH3)((CH2))2-). n The structure represented by OH)-) can be arranged in a block copolymer or random copolymer manner.

[0102] The moisture reduction effect is further improved when the polysiloxane segment has a polysiloxane forming a urethane structure containing the structure represented by formula (3). This is presumably due to the presence of siloxane near the urethane backbone. In formula (3), I is preferably an integer from 40 to 160, m is preferably an integer from 2 to 10, and n is preferably an integer from 1 to 3.

[0103] Polysiloxane segments can be bonded to the polyurethane backbone via a structure represented by the following formula (4).

[0104]

[0105] (In Equation (4), "*" represents the polyurethane skeleton)

[0106] The -O- on the left side of the structure represented by equation (4) is bonded to the Si in the structure represented by equation (1). The Si in the structure represented by equation (4) is bonded to the -O- in the siloxane structure. That is, the repeating structure of the siloxane can be bonded to both sides of the structure represented by equation (4).

[0107] Methods for measuring stored elastic modulus

[0108] The storage modulus can be obtained by measuring the dynamic viscoelasticity of a sample under set frequency and temperature conditions using a dynamic viscoelasticity device, and by plotting the master curve at a reference temperature based on the measurement data.

[0109] The overall curve is plotted based on the time-temperature offset rule. The horizontal axis represents frequency, and the vertical axis represents the elastic modulus. The overall curve can be plotted by shifting the frequency dispersion data measured at each temperature along the horizontal axis so that it overlaps with the reference temperature data.

[0110] From the obtained overall curve, for example, by curve fitting based on the generalized Maxwell model and formulating it, the elastic member in 1×10 can be calculated. -3 Storage elastic modulus at Hz.

[0111] Methods for measuring crosslinking density

[0112] The crosslinking density of polyurethane can be indirectly measured based on the spin-spin relaxation time in pulsed NMR.

[0113] When the crosslinking density is low, the molecular mobility of the chain segments is high and relaxation takes time; therefore, the spin-spin relaxation time (T2) is long. L It gets longer.

[0114] The spin-spin relaxation time (T2) was measured using a pulsed NMR apparatus via solid-state echo method.

[0115] A pulsed NMR apparatus is used to evaluate the mobility of polymer molecules, such as rubber, by measuring the mobility (relaxation time) of hydrogen atoms in the molecular chain. In this embodiment, solid-state echo is used as the sequence. The solid-state echo method using the pulsed NMR apparatus itself can be a known method and is not particularly limited.

[0116] The T2 relaxation curve (free induction decay curve) is obtained by measuring the spin-spin relaxation time T2 (transverse relaxation time) based on pulse NMR measurements.

[0117] In this embodiment, the T2 relaxation curve is divided into two components based on the length of the relaxation time. Specifically, the T2 relaxation curve is divided into two components by curve fitting the following formula, and the T2 relaxation time (T2) of the component with the longer relaxation time is calculated. L ) and the T2 relaxation time (T2) of components with short relaxation times S ).

[0118]

[0119] M(t): Macroscopic magnetization

[0120] A L The intensity of the component with a long relaxation time at t=0

[0121] T2 L T2 relaxation time of components with long relaxation times

[0122] A S The intensity of the component with a short relaxation time at t=0

[0123] T2 ST2 relaxation time of components with short relaxation times

[0124] mi: Weibull coefficient

[0125] Measurement methods for siloxane components

[0126] Analytical methods for siloxane components can be performed as follows. For example, a method using trimethyl orthoformate as a methoxyl derivative is known. Trimethyl orthoformate, methanol, sulfuric acid, and an elastic component are mixed and reacted at reflux temperature for several hours, thus decomposing the siloxane segments into siloxane units. The sample is then analyzed by GC-MS or similar methods, allowing for the analysis and quantification of the structure.

[0127] More specifically, the analysis can be performed as follows.

[0128] The structure represented by equation (1) can be quantified by the following method.

[0129] 524 mg of silicone oil (commercially available from Shin-Etsu Chemical Co., Ltd. as a standard), 272 mg of sulfuric acid, 28.4 g of trimethyl orthoformate, and 8.75 g of methanol were mixed and reacted at reflux temperature for 5 hours. The resulting solution was diluted with solvent to prepare four different concentration levels of samples. The four concentration levels of samples were analyzed by GC-MS, and calibration curves were plotted using the peak intensities and concentrations of the Si-O components.

[0130] Next, a measurement sample is cut from the center of the elastic component of the cleaning scraper.

[0131] 524 mg of the sample was mixed with 272 mg of sulfuric acid, 28.4 g of trimethyl orthoformate, and 8.75 g of methanol, and the mixture was reacted at reflux temperature for 5 hours. The supernatant after the reaction was sampled and analyzed by GC-MS. The mass percentage of the structure represented by equation (1) in the polyurethane elastomer was calculated from the peak intensity of the Si-O component and the calibration curve.

[0132] For the structure represented by equation (2), it can be obtained through... 1 H-NMR analysis of the post-reaction sample was used to estimate the structure. When the polyurethane elastomer has a structure represented by formula (2), that is, when a side-chain modified silicone oil is used, two methoxy groups and one methyl group are bonded to the Si at the end of the polyurethane elastomer in the structure.

[0133] On the other hand, when end-modified silicone oil is used, one methoxy group and two methyl groups are bonded to the Si group at the end of the polyurethane elastomer in the structure. The structure can be inferred from the peak intensity ratio of the two bonds.

[0134] isocyanurate bond

[0135] As the crosslinking density of polyurethane increases, the elastic modulus of the elastic component tends to increase, the roller gap in contact with the component being cleaned narrows, and this is detrimental to contact stability. To increase the crosslinking density and prevent the elastic modulus from becoming too high, the amount of rigid component in the polyurethane elastomer can be reduced.

[0136] As a rigid component, it is preferable to minimize the number of isocyanurate bonds and have abundant urethane bonds. Specifically, in FT-IR measurements using diamond as the elastic component of the ATR crystal, 1,415 cm⁻¹ -1 Peak intensity at 1,538 cm⁻¹ -1 The ratio of peak intensity values ​​at (1,415 cm⁻¹) -1 Peak intensity value at 1,538 cm⁻¹ -1 The peak intensity at the specified point is preferably 0.50 to 0.65.

[0137] FT-IR analysis of 1,415 cm⁻¹ using diamond as the elastic component of an ATR crystal -1 The peak at 1538 cm⁻¹ corresponds to the isocyanurate ring. On the other hand, the peak at 1538 cm⁻¹... -1 The peak at 1,415 cm⁻¹ corresponds to the NH deformation angle of the urethane bond. -1 Peak intensity at 1,538 cm⁻¹ -1 A peak intensity value in the range of 0.50 to 0.65 indicates a low number of isocyanurate bonds in the elastic component.

[0138] When 1,415cm -1 Peak intensity at 1,538 cm⁻¹ -1 When the peak intensity value (peak intensity ratio) is greater than 0.65, it indicates that there are a large number of isocyanurate bonds in the elastic component. When the peak intensity ratio is between 0.50 and 0.65, an elastic component with a storage modulus that is not too large and excellent contact stability with the component being cleaned can be obtained.

[0139] In order to make 1,415cm -1 Peak intensity at 1,538 cm⁻¹ -1 Setting the peak intensity value within the specific range mentioned above can illustrate methods for reducing the number of isocyanurate bonds and enriching the product with urethane. Specific examples include using a urethane esterification catalyst instead of a catalyst that promotes isocyanurate formation, making the mixing ratio of -NCO and -OH in the prepolymer close to 1, and maintaining the reaction temperature when the prepolymer material reacts below 100°C.

[0140] Polymer MDI

[0141] When the side of the cleaning squeegee that contacts the surface of the component being cleaned is defined as the front end side of the cleaning squeegee, the elastic member has a plate shape, which has at least a main surface (4) facing the component being cleaned and a front end surface (5) forming the front end edge together with the main surface on the front end side. Here, it is assumed that a third line segment parallel to the front end edge and 0.5 mm away from the front end edge is drawn on the front end surface. Here, the length of the third line segment is denoted as L', and the points on the third line segment that are 1 / 8L', 1 / 2L', and 7 / 8L' away from one end are denoted as P0', P1', and P2', respectively.

[0142] Samples taken at each of P0', P1', and P2' are heated and vaporized in an ionization chamber, and heated to 1,000°C at a heating rate of 10°C / s using a direct sample introduction mass spectrometer that ionizes the sample molecules. The detected amounts of all ions thus obtained are denoted as M1, and the integrated intensity of the peaks in the extracted ion thermograms corresponding to m / z values ​​in the range of 380.5 to 381.5 derived from polymeric MDI is denoted as M2. In this case, M2 / M1 is preferably less than 0.0010.

[0143] As the isocyanate, 4,4'-MDI, which has high reactivity and in which the two isocyanate groups have equal reactivity, is preferred. On the other hand, as mentioned above, it is preferable to minimize the amount of polymeric MDI used as a trifunctional MDI, and particularly preferably to use none at all. Specifically, M2 / M1 is preferably less than 0.0010. When M2 / M1 meets the specific range described above, the storage modulus can fall within a favorable range.

[0144] M2 / M1 is more preferably 0.0009 or less. A smaller M2 / M1 is preferred, and there is no particular limitation on the lower limit, but it is more preferably 0.0000 or more.

[0145] When M2 / M1 is above 0.0010, the storage elastic modulus tends to be large due to the stiffness of polymeric MDI.

[0146] Furthermore, it is preferable to minimize the amount of crystalline structures in the polyurethane. Specifically, it is preferable to minimize the amount of materials that readily form crystalline structures, such as 1,4-butanediol, and to use an abundant amount of crosslinking agents, such as trimethylolpropane. Crosslinking agents, such as trimethylolpropane, facilitate the creation of distances between urethane bonds and make it difficult for crystalline structures to form.

[0147] High cross-linking density

[0148] Examples of methods for increasing crosslinking density include increasing the concentration of the crosslinking agent in the raw material composition of the elastic member. Considering the storage elastic modulus, 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.

[0149] The following describes the method for calculating the crosslinking agent concentration. For example, it can be quantified by pyrolysis GC / MS.

[0150] Polyols were detected by pyrolysis GC / MS. The measurement conditions are as follows.

[0151] Device:

[0152] Pyrolysis apparatus: EGA / PY-3030D (product name, available from Frontier Laboratories Ltd.)

[0153] Gas chromatography apparatus: TRACE 1310 gas chromatograph (product name, commercially available from Thermo Fisher Scientific Inc.)

[0154] Mass spectrometer: ISQLT (product name, commercially available from Thermo Fisher Scientific Inc.)

[0155] Pyrolysis temperature: 500℃

[0156] GC column: 0.25mm inner diameter × 30m stainless steel capillary column

[0157] Stationary phase 5% phenyl polydimethylsiloxane

[0158] Heating conditions: Maintain at 50°C for 3 minutes and then heat to 300°C at a rate of 8°C / min.

[0159] MS conditions: mass range m / z 10 to 650

[0160] Scanning speed: 1 second / scan

[0161] The type of polyol was determined by GC / MS. Calibration curves were plotted by GC analysis of the polyol species at known concentrations, quantification was performed by the GC peak area ratio, and the concentration of crosslinking agent in the feedstock composition was calculated.

[0162] When the elastic member is placed in an environment with a temperature of 24°C and a relative humidity of 50% for more than 24 hours, the hardness is preferably 60.0 to 90.0, and more preferably 70.0 to 80.0. The hardness is the International Rubber Hardness (IRHD) and is a value measured using a hardness tester according to the International Rubber Hardness Test Method M as specified in JIS K 6253.

[0163] When the hardness of the elastic member after being placed in an environment with a temperature of 24°C and a relative humidity of 50% for more than 24 hours is the initial hardness, and the hardness of the elastic member after being moved to an environment with a temperature of 24°C and a relative humidity of 95% and placed for more than 24 hours is the hardness after placement, the hardness reduction rate calculated by the following formula is preferably 0.20 to 0.90%, and more preferably 0.30 to 0.85%.

[0164] Hardness reduction rate (%) = (Initial hardness at 50% relative humidity - Hardness after placement at 95% relative humidity) / Hardness at 50% relative humidity × 100

[0165] The initial hardness and the hardness after placement are the International Rubber Hardness (IRHD) values, and are measured using a hardness tester according to the International Rubber Hardness Test Method M as specified in JIS K6253.

[0166] Constituent materials

[0167] Supporting components

[0168] The cleaning scraper disclosed herein has a support member that supports an elastic member. There are no particular limitations on the material constituting the support member, and examples include: metallic materials such as steel plate, stainless steel plate, galvanized steel plate, and chromium-free steel plate, and resin materials such as 6-nylon and 6,6-nylon.

[0169] Furthermore, there are no particular restrictions on the shape and structure of the supporting components. For example, such as Figure 2 One end of the elastic member of the cleaning scraper shown is supported by a support member.

[0170] elastic member

[0171] Elastic components include polyurethane elastomers having polysiloxane segments. Besides polysiloxanes, the polyurethane elastomers constituting elastic components are mainly obtained from raw materials such as polyols, chain extenders, crosslinking agents, polyisocyanates, catalysts, and other additives.

[0172] Polyurethane elastomers are the product of the reaction between urethane prepolymers and silicone oils having functional groups that can react with isocyanate groups (or hydroxyl groups). The urethane prepolymers are the product of the reaction between polyols and polyisocyanates.

[0173] The following describes in detail the raw materials used in polyurethane elastomers.

[0174] As polysiloxanes, various modified silicone oils having a dimethylsiloxane structure and reactive groups can be used. Methanol-modified silicone oils are preferred. Examples include terminally modified methanol-modified silicone oils and side-chain modified methanol-modified silicone oils. Among them, methanol-modified silicone oils with primary hydroxyl groups at the end are more preferred because they have high reactivity with isocyanates and are easily fixed in polyurethane elastomers. For example, commercially available products such as "KF-6001" (product name, available from Shin-Etsu Chemical Co., Ltd.), "Silmer OH J10" (product name, available from Siltech Corporation) and "X-22-4039" (product name, available from Shin-Etsu Chemical Co., Ltd.) can be used.

[0175] Examples of polyols include: polyester polyols, such as polyethylene adipate polyol, polybutylene adipate polyol, polyhexane adipate polyol, (ethylene / polypropylene)adipate polyol, (ethylene / polybutylene)adipate polyol, and (ethylene / polyopentylene)adipate polyol; polycaprolactone polyols obtained by ring-opening polymerization of caprolactone; polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; and polycarbonate diols, etc. These can be used alone or in combination of two or more.

[0176] Among these polyols, polyester polyols containing adipate esters are preferred because they produce polyurethane elastomers exhibiting excellent mechanical properties. Polyester polyols containing butylene adipate are even more preferred. For example, commercially available products such as "NIPPOLLAN 3027" (product name, available from Tosoh Corporation) with a number average molecular weight of 2,500 and "NIPPOLLAN 4010" (product name, available from Tosoh Corporation) with a number average molecular weight of 2,000 can be used.

[0177] As chain extenders, diols and polyols with three or more components that can extend the chains of polyurethane elastomers can be used.

[0178] Diols can be exemplified by the following: 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-cyclohexanediol, xylenediol (terephthalic acid diethanol) and triethylene glycol.

[0179] Examples of polyols with three or more nucleotides include trimethylolpropane, glycerol, pentaerythritol, and sorbitol. These can be used alone or in combination of two or more. It is preferred to use these polyols with three or more nucleotides as crosslinking agents. Among the aforementioned polyols, trimethylolpropane is more preferred.

[0180] Examples of polyisocyanates include: 4,4'-diphenylmethane diisocyanate (4,4'-MDI), polymeric MDI (pMDI), 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), xylene diisocyanate (XDI), 1,5-naphthalene 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, which has high reactivity and whose two isocyanate groups have equal reactivity, is preferred.

[0181] Catalysts commonly used for curing polyurethane elastomers can be used as the aforementioned catalysts. Tertiary amine catalysts are examples of such catalysts, and specific examples include: 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. Organoacid salts of metals, such as potassium acetate and basic potassium octanoate, can also be used. Metal catalysts commonly used for urethane esterification, such as dibutyltin dilaurate, can also be used. These can be used alone or in combination of two or more.

[0182] N,N′-dimethylhexanolamine is preferred as a catalyst. Examples include commercially available product Kaolizer No. 25 (available from Kao Corporation). Additionally, an ethylene glycol solution of potassium acetate is also preferred. Examples include commercially available product POLYCAT46 (available from Air Products Japan, KK).

[0183] For example, polyurethane elastomers preferably contain at least one polyol selected from the group consisting of polyester polyols and polyether polyols, ternary or higher polyols, and 4,4'-MDI as constituent components. Additives, such as pigments, plasticizers, waterproofing agents, oxidation inhibitors, ultraviolet absorbers, and light stabilizers, may optionally be blended into the raw material used for elastic components.

[0184] Production method of cleaning scrapers

[0185] The method for producing the cleaning scraper according to this disclosure is not particularly limited, and a suitable method can be selected from known methods.

[0186] There are no particular limitations on the production method of elastic components containing polyurethane elastomers, but it is preferable to include, for example, the following steps. The polyurethane elastomer composition is preferably prepared by a prepolymer method using a prepolymer with a molecular weight distribution that is as uniform as possible. This method preferably first includes a step of reacting a polyol with a polyisocyanate to obtain the prepolymer. The NCO content in the prepolymer is not particularly limited, but is preferably 3.00–15.00% by mass, and more preferably 6.00–10.00% by mass.

[0187] Subsequently, a mixture of polysiloxane, crosslinking agent, and catalyst (curing agent) is added to the obtained prepolymer and mixed to obtain a polyurethane elastomer composition. Polyols may be added to the curing agent.

[0188] After the support member is placed in a mold for forming a cleaning scraper, a polyurethane elastomer composition is injected into the mold cavity, heated, and cured, thereby obtaining a cleaning scraper in which the plate-shaped scraper member and the support member are integrated. A known release agent can be applied to the mold. Alternatively, a polyurethane elastomer sheet can be separately formed from the aforementioned polyurethane raw material composition, cut into strips to obtain elastic members, the bonding area of ​​which can cover the support member that has been coated or bonded with adhesive, and bonding can be achieved by applying heat and pressure.

[0189] In addition, polyurethane elastomer compositions can also be used as materials for urethane molded articles. For example, a polyurethane elastomer composition can be injected into a sheet mold, cured, and then demolded to form a urethane molded article.

[0190] Processing box and electrophotographic image forming equipment

[0191] A cleaning squeegee can be used by introducing it into a processing cartridge removable from the electrophotographic image forming apparatus. Specifically, for example, a cleaning squeegee according to this method can be used as a cleaning squeegee in a processing cartridge that includes an image carrier member as the member to be cleaned and a cleaning squeegee capable of cleaning the surface of the image carrier member. The processing cartridge helps to stably form high-quality electrophotographic images.

[0192] Furthermore, an electrophotographic image forming apparatus according to one aspect of the present invention includes an image-bearing member, such as a photosensitive member, and a cleaning blade configured to clean the surface of the image-bearing member, wherein the cleaning blade is a cleaning blade according to this aspect. The electrophotographic image forming apparatus can stably form high-quality electrophotographic images.

[0193] Example

[0194] The invention will be described below with reference to production examples, embodiments, and comparative examples, but this disclosure is not limited to these embodiments. Reagents or industrial chemicals other than those shown in the embodiments and comparative examples may be used as raw materials.

[0195] In the following Examples 1 to 14 and Comparative Examples 1 to 5, production and evaluation were carried out. Figure 1 The integrated cleaning scraper is shown. Tables 1 and 2 show the formulations of the polyurethane elastomer compositions of the examples and comparative examples, as well as the physical properties and evaluation results of the obtained elastic components.

[0196] Example 1

[0197] Supporting components

[0198] Prepare 1.6mm thick galvanized steel sheets and process them to obtain support components with L-shaped cross-sections, such as... Figure 2 As shown in Figure 3.

[0199] Here, a urethane-metal monolayer adhesive (product name: Chemlok 219, available from LORD Corporation) is applied to the portion of the support member that contacts the elastic member.

[0200] Preparation of raw materials for elastic components

[0201] prepolymer

[0202] • As an isocyanate, 4,4'-diphenylmethane diisocyanate (product name: Millionate MT, available from Tosoh Corporation) (hereinafter referred to as 4,4'-MDI) 327.0g

[0203] • As a polyol, 673.0g of butylene adipate polyester polyol (product name: NIPPOLLAN 3027, commercially available from Tosoh Corporation) (hereinafter referred to as PBA2500) with a number average molecular weight of 2,500.

[0204] The material was reacted at 80°C for 3 hours to obtain a prepolymer with an NCO content of 8.80% by mass.

[0205] curing agent

[0206] • Trimethylolpropane (commercially available from Tokyo Chemical Industry Co., Ltd.) (hereinafter referred to as TMP) 84.3g

[0207] ·N,N'-Dimethylhexanolamine (product name: Kaolizer No. 25, available from Kao Corporation) (hereinafter referred to as No. 25) 0.25g

[0208] • Methanol-modified silicone oil (product name: KF-6001, commercially available from Shin-Etsu Chemical Co., Ltd.) (hereinafter referred to as KF-6001) 8.7g

[0209] The materials are mixed to prepare a curing agent.

[0210] The curing agent is mixed with the obtained prepolymer to obtain a polyurethane elastomer composition.

[0211] The support member is configured such that the adhesive application portion protrudes into the mold cavity of the mold used to shape the cleaning scraper. A polyurethane elastomer composition is injected into the mold used to shape the cleaning scraper, cured at 130°C for 5 minutes, and then demolded to obtain an integral molded body of the polyurethane and the support member.

[0212] As a mold, a mold coated with release agent A is used before injecting the polyurethane elastomer composition. Release agent A is a mixture of 5.06 g of ELEMENT14 PDMS1000-JC (product name, available from Momentive Performance Materials), 6.19 g of ELEMENT14 PDMS 10K-JC (product name, available from Momentive Performance Materials), 3.75 g of SR1000 (product name, available from Momentive Performance Materials), and 85 g of EXXSOL DSP145 / 160.

[0213] The front end of the polyurethane elastomer of the integrally molded body is appropriately cut to obtain a plate-shaped elastic member having a main face and a front end edge formed together with the main face. The angle of the front end edge is 90 degrees, and the distances in the short side direction, thickness direction, and long side direction of the elastic member are 7.5 mm, 1.8 mm, and 240 mm, respectively.

[0214] The obtained cleaning scraper was evaluated using the following methods.

[0215] Method for calculating the storage elastic modulus

[0216] The stored elastic modulus of the elastic component was calculated by measuring temperature-frequency changes using a dynamic viscoelastic device and plotting the overall curve at a reference temperature of 24°C based on the time-temperature offset rule.

[0217] The dynamic viscoelasticity measurement conditions are as follows:

[0218] Apparatus: Dynamic viscoelasticity measuring device (product name: DMA EXPLEXOR 500N, available from NETZSCH Group)

[0219] Measurement mode: Tension

[0220] Static strain: 2%

[0221] Dynamic strain: 0.5%

[0222] Temperature measurement: -30℃ to 80℃ (in 2℃ increments, 56 points)

[0223] Measurement frequency: 0.1 to 100 Hz (5 points)

[0224] The overall curve was plotted at a reference temperature of 24°C using the software within the device, based on the obtained dynamic viscoelasticity measurement results.

[0225] The obtained total curve is mathematically approximated based on the generalized Maxwell model.

[0226] The generalized Maxwell model is as follows:

[0227]

[0228] The generalized Maxwell model is divided into storage elastic modulus E' and loss elastic modulus E as follows.

[0229]

[0230] In the mathematical approximation, the number of terms in the generalized Maxwell model is set as the elastic term (Ee)1 + the viscoelastic term (Ei)20 (i = 1 to 20). τi is at 10 -8 and 10 5 Set 20 points between them.

[0231] The nonlinear generalized reduced gradient (GRG) method is used to optimize Ee and Ei, minimizing the differences between E' and E” of the generalized Maxwell model and E' and E” in the overall curve. Specifically, the solver function of Excel is used.

[0232] From the obtained approximate expression of the total curve, calculate E'(1)(1×10 -3 E' at Hz), and used as an elastic member at 1×10 -3 Storage elastic modulus at a vibration frequency of Hz.

[0233] Here, the sample for measurement is prepared as follows.

[0234] The sample is prepared such that it includes the angle (e.g., the front edge) of the portion of the elastic member that contacts the member being cleaned. The sample is prepared by cutting it into strips with a length of 50 mm, a width of 2 mm, and a thickness of 1.8 mm.

[0235] Measurement of T2 relaxation time

[0236] The spin-spin relaxation time (T2) was measured using the solid-state echo method in pulsed NMR analysis.

[0237] The sample used is either an elastic component of a cleaning scraper cut from the measurement location as described below, or a urethane molded body as described below. The sample is cut into small pieces with a size of 1 mm × 1 mm, and 1 g of the cut pieces is placed in a test tube.

[0238] The pulse NMR measurement conditions are as follows:

[0239] Device: JNM-MU25 (available from JEOL Ltd.)

[0240] Conditions: Solid-state echo method

[0241] Measurement environment: 50℃

[0242] Number of measurements: 128

[0243] The measurement results were divided into two components using the least squares method through the software within the device, and the corresponding spin-spin relaxation times (T2) were obtained. L and T2 S ).

[0244] In this disclosure, the obtained T2 relaxation curve is divided into two components based on the length of the relaxation time. Specifically, the T2 relaxation curve is divided into two components by curve fitting to the following formula, and the spin-spin relaxation time (T2) of the component with the longer relaxation time is calculated. L ) and the spin-spin relaxation time (T2) of components with short relaxation timesS ).

[0245]

[0246] M(t): Macroscopic magnetization

[0247] A L The intensity of the component with a long relaxation time at t=0

[0248] T2 L T2 relaxation time of components with long relaxation times

[0249] A S The intensity of the component with a short relaxation time at t=0

[0250] T2 S T2 relaxation time of components with short relaxation times

[0251] mi: Weibull coefficient

[0252] Measurement locations: When the length of the front edge of the cleaning scraper is L, samples are taken and measured at positions 1 / 8L, 1 / 2L, and 7 / 8L away from one end of the edge, as described above. The arithmetic mean is shown in Table 1.

[0253] FT-IR analysis of elastic components using the ATR method

[0254] The elastic member at 1,415 cm was measured using the ATR method with FT-IR. -1 The peak intensity values ​​at 1,538 cm⁻¹ and at 1,538 cm⁻¹ -1 The value of the peak intensity at that location.

[0255] Use the sample cut from the elastic component of the cleaning scraper at the measurement location described below.

[0256] The FT-IR measurement conditions are as follows.

[0257] Device: FT / IR-4700 (available commercially from JASCO Corporation)

[0258] Measurement mode: ATR method (crystal: diamond)

[0259] Total number of measurements: 64

[0260] Measurement location: When the length of the front edge of the cleaning scraper is L, measurements are taken at positions 1 / 8L, 1 / 2L, and 7 / 8L away from one end of the edge.

[0261] Calculate 1,415 cm⁻¹ from the obtained peak intensity. -1 Peak intensity at 1,538 cm⁻¹ -1The peak intensity values ​​at the specified locations are shown in Table 1, and their arithmetic mean is also presented.

[0262] Measurement methods for M1 and M2

[0263] M1 and M2 are measured by the direct sample introduction method (DI method), in which the sample is introduced directly into the ion source without gas chromatography (GC).

[0264] The device used was a POLARIS Q (commercially available from Thermo Fisher Scientific Inc.), and a direct exposure probe (DEP) was used.

[0265] Assume a line segment is drawn on the front surface of an elastic member parallel to the front edge, at a distance of 0.5 mm from the front edge. When the length of the line segment is L', the points 1 / 8L', 1 / 2L', and 7 / 8L' away from one end of the line segment are defined as P0', P1', and P2', respectively. Use a bio-cutter to scrape away the polyurethane at P0', P1', and P2'.

[0266] μg of sample taken at each of P0', P1', and P2' was fixed to a filament located at the tip of the probe and directly inserted into the ionization chamber. The sample was then rapidly heated from room temperature to 1,000°C at a controlled heating rate (10°C / s), and the vaporized gas was detected by mass spectrometry.

[0267] M1 is the sum of the integrated intensities of all peaks in the obtained total ion current thermogram, representing the amount of all detected ions.

[0268] The integrated intensity of the peak in the extracted ionothermal spectrum corresponding to the m / z value in the range of 380.5 to 381.5 derived from polymeric MDI is defined as M2, and M2 / M1 is calculated. Here, the arithmetic mean of the values ​​obtained at each of P0', P1', and P2' is taken as the value of M2 / M1 in this disclosure.

[0269] Evaluation of moisture absorption rate

[0270] A 7.5mm wide x 30mm long and 1.8mm thick sheet is cut from the center of the elastic component of the cleaning scraper. This sheet is then placed in an environment with a temperature of 24°C and a relative humidity of 50% for at least 24 hours, and the initial weight is measured. The 30mm length of the sheet refers to the portion of the cleaning scraper along its long side.

[0271] Next, the sample was placed in an environment with a temperature of 24°C and a relative humidity of 95% for more than 24 hours. The weight after placement was then measured, and the moisture absorption rate was calculated using the following formula.

[0272] Moisture absorption rate (%) = (Weight after placement at 95% relative humidity - Initial weight at 50% relative humidity) / Initial weight at 50% relative humidity × 100

[0273] Evaluation of hardness reduction rate

[0274] A sheet measuring 7.5 mm wide, 10 mm long, and 1.8 mm thick is cut from the center of the elastic component of the cleaning scraper and placed in an environment with a temperature of 24°C and a relative humidity of 50% for more than 24 hours. The initial hardness (IRHD) is then measured under the following conditions. The 30 mm length of the sheet is the portion of the cleaning scraper along its length.

[0275] Apparatus: Wallace hardness tester (available from Wallace Instruments)

[0276] Conditions: International Rubber Hardness Test Method M as specified in JIS K 6253

[0277] Hardness: International Rubber Hardness (IRHD)

[0278] Next, the sample was moved to an environment with a temperature of 24°C and a relative humidity of 95% and left for more than 24 hours. Then, the hardness after placement was measured under the same conditions as above, and the hardness reduction rate was calculated using the following formula.

[0279] Hardness reduction rate (%) = (Initial hardness at 50% relative humidity - Hardness after placement at 95% relative humidity) / Hardness at 50% relative humidity × 100

[0280] Evaluation of cleaning performance

[0281] Modify the motor of the color laser beam printer (product name: HP Color LaserJet Enterprise 5700dn, commercially available from HP Inc.) to double the drive speed. Introduce the cleaning blade obtained by the above method into the cyan cartridge of the printer as a cleaning blade for the photosensitive component to be cleaned. Additionally, replace all the toner in the cyan cartridge's developer with toner 1 described later.

[0282] Next, the printer was placed in a high humidity environment (temperature 24°C and relative humidity 95%) for 24 hours, then moved to an environment with a temperature of 24°C and relative humidity of 80%, and images were formed on 10,000 sheets. After forming images on 10,000 sheets, halftone images were output as evaluation images. The images were visually inspected for image defects (stripes on the image) caused by the cleaning blade, and the images were evaluated.

[0283] A: No image defects occurred.

[0284] B: Image corruption occurred.

[0285] Production method of colorant 1

[0286] As an evaluation toner, toner 1 produced by the following method is used. Here, unless otherwise stated, all "parts" are based on mass.

[0287] Preparation steps of aqueous medium 1

[0288] 650.0 parts of deionized water were placed in a reaction vessel including a stirrer, thermometer, and reflux tube. 14.0 parts of sodium phosphate (12-hydrate, commercially available from Rasa Industries, Ltd.) were added, and the mixture was kept at 65°C for 1.0 hour while purging with nitrogen. Using a TK homogenizer (commercially available from Tokushu Kika Kogyo Co., Ltd.), the mixture was stirred at 15,000 rpm while adding 9.2 parts of calcium chloride (dihydrate) dissolved in 10.0 parts of deionized water to prepare an aqueous medium containing a dispersion stabilizer. Additionally, 10% by mass hydrochloric acid was added to the aqueous medium to adjust the pH to 5.0, thus obtaining aqueous medium 1.

[0289] Preparation steps of polymerizable monomer compositions

[0290] • Styrene: 60.0 parts

[0291] • CI Pigment Blue 15:3 6.5 parts

[0292] These materials were added to a grinder (commercially available from Mitsui Miike Machinery Co., Ltd.) and further dispersed at 220 rpm for 5.0 hours using zirconia particles with a diameter of 1.7 mm to prepare a pigment dispersion. The following materials were added to the pigment dispersion.

[0293] Styrene: 20.0 parts

[0294] · 20.0 parts of n-butyl acrylate

[0295] • Crosslinking agent (divinylbenzene) 0.3 parts

[0296] 5.0 parts of saturated polyester resin

[0297] (The polycondensation product of propylene oxide-modified bisphenol A (2 molar adduct) and terephthalic acid (molar ratio 10:12), glass transition temperature Tg = 68℃, weight-average molecular weight Mw = 10,000, molecular weight distribution Mw / Mn = 5.12)

[0298] • Fischer-Tropsch wax (melting point 78°C) 7.0 parts

[0299] These materials were kept at 65°C and fully dissolved and dispersed at 500 rpm using a TK homogenizer (commercially available from Tokushu Kika Kogyo Co., Ltd.) to prepare a polymerizable monomer composition.

[0300] Granulation steps

[0301] While maintaining the temperature of aqueous medium 1 at 70°C and the rotation speed of the TK homogenizer at 15,000 rpm, the polymerizable monomer composition was added to aqueous medium 1, along with 10.0 parts of tert-butyl peroxypentanoate as a polymerization initiator. Granulation was carried out directly for 10 minutes while maintaining the stirring speed at 15,000 rpm.

[0302] Polymerization and distillation steps

[0303] After the granulation step, the agitator was replaced with a propeller agitator blade, and polymerization was carried out for 5.0 hours while stirring at 150 rpm and maintaining 70°C. The temperature was then raised to 85°C and heated for 2.0 hours to induce the polymerization reaction.

[0304] Then, the reflux tube of the reaction vessel was replaced with a cooling tube, the slurry was heated to 100°C, and distilled for 6 hours to distill off unreacted polymerizable monomers, in order to obtain a toner-based particle dispersion.

[0305] Polymerization of organosilicon compounds

[0306] Weigh 60.0 parts of deionized water into a reaction vessel including a stirrer and a thermometer, and adjust the pH to 4.0 using 10% hydrochloric acid by mass. Heat while stirring until the temperature reaches 40°C.

[0307] Then, 40.0 parts of methyltriethoxysilane as an organosilicon compound were added, and the mixture was stirred for more than 2 hours to carry out hydrolysis. When the oil and water no longer separated and remained in a monolayer, the endpoint of hydrolysis was visually confirmed, and the mixture was cooled to obtain a hydrolysate containing the organosilicon compound.

[0308] The obtained toner base particle dispersion was cooled to 55°C, and then 25.0 parts of a hydrolysate solution of the organosilicon compound were added to initiate the polymerization of the organosilicon compound. After holding the mixture constant for 15 minutes, the pH was adjusted to 5.5 using a 3.0% by weight aqueous solution of sodium bicarbonate. The mixture was held at 55°C for 60 minutes while continuing to stir, and then the pH was adjusted to 9.5 using a 3.0% by weight aqueous solution of sodium bicarbonate. The mixture was then held for an additional 240 minutes to obtain the toner particle dispersion.

[0309] Washing and drying steps

[0310] After the polymerization step is completed, the toner particle dispersion is cooled, hydrochloric acid is added to the toner particle dispersion to adjust the pH to below 1.5, and the mixture is stirred and left to stand for 1 hour. Then, solid-liquid separation is performed using a pressure filter to obtain a toner filter cake. The mixture is then re-slurryed using deionized water to prepare a dispersion again, and then solid-liquid separation is performed using the same filter to obtain the toner filter cake.

[0311] The obtained toner filter cake was dried at 40°C in a constant temperature room and graded for 72 hours to obtain toner 1.

[0312] Examples 2 to 14 and Comparative Examples 1 to 5

[0313] Except for changes in the formulation materials and their amounts as shown in Tables 1 and 2, the prepolymer, curing agent, and polysiloxane were prepared and mixed in the same manner as in Example 1, thereby obtaining a polyurethane elastomer composition. Cleaning squeegees were prepared using the obtained polyurethane elastomer composition, and the obtained cleaning squeegees were evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 1 and 2.

[0314] In addition to the materials shown in Example 1, details of the materials used are as follows.

[0315] Polybutylene adipate polyester polyol with a number average molecular weight of 2,000 (product name: NIPPOLLAN 4010, commercially available from Tosoh Corporation) (hereinafter referred to as PBA2000).

[0316] Polyhexyl adipate polyester polyol with a number average molecular weight of 1,000 (product name: NIPPOLLAN 164, commercially available from Tosoh Corporation) (hereinafter referred to as PHA1000).

[0317] Polymerized MDI (product name: Millionate MR-400, available commercially from Tosoh Corporation) (hereinafter referred to as pMDI)

[0318] 1,4-Butanediol (commercially available from Tokyo Chemical Industry Co., Ltd.) (hereinafter referred to as 1,4-BD)

[0319] POLYCAT46 (available from Air Products Japan, KK) (hereinafter referred to as PC46)

[0320] Silmer OH J10 (available from Siltech Corporation)

[0321] X-22-4039 (available from Shin-Etsu Chemical Co., Ltd.)

[0322] KF-96A-100cs (available commercially from Shin-Etsu Chemical Co., Ltd.)

[0323] In Comparative Example 1, since it did not contain a siloxane component, the moisture reduction effect was small, and poor image quality occurred. In Comparative Example 2, although it contained a siloxane component, since it was not fixed in the polyurethane elastomer, the moisture reduction effect was small, and poor image quality occurred. In Comparative Example 3, although it contained siloxane segments, due to T2... L The large storage modulus and low crosslinking density result in a small moisture absorption reduction effect and poor image quality. In Comparative Example 4, the small storage modulus leads to low contact force and poor image quality. In Comparative Example 5, the large storage modulus results in unstable roll gap formation and poor image quality.

[0324] Example 15

[0325] A polyurethane elastomer composition having the same formulation as in Example 9 was injected into a sheet mold with a thickness of 2 mm and cured at 130°C for 5 minutes, and then demolded to obtain a urethane molded body with a thickness of 2 mm. Here, a mold coated with the above-mentioned release agent A was used as the sheet mold.

[0326] The moisture absorption and hardness reduction of the obtained urethane molded articles were measured in the same manner as in Example 1. The evaluation results are shown in Table 3.

[0327]

[0328] In the table, the content of the structure represented by equation (1) indicates the content (mass%) of the structure represented by equation (1) in the polyurethane elastomer. Additionally, a value of 0 for m in equation (2) indicates that the polyurethane elastomer does not have the structure represented by equation (2). Hardness (IRHD) represents the hardness (initial hardness) of the elastic member after being placed in an environment with a temperature of 24°C and a relative humidity of 50% for 24 hours.

[0329]

[0330] [Table 3]

[0331]

[0332] While this disclosure has been described with reference to exemplary embodiments, it should be understood that this disclosure is not limited to the disclosed exemplary embodiments. The scope of the appended claims is to be given the broadest interpretation in order to cover all such modifications and equivalent structures and functions.

Claims

1. An electronic photographic cleaning squeegee, comprising: Elastic components including polyurethane, and Supporting member that supports the elastic member; The electrophotographic cleaning squeegee cleans the surface of the component being cleaned by bringing a portion of the elastic member into contact with the surface of the moving component being cleaned. In an environment of 24°C, the elastic member exhibits a strength of 1×10⁻⁶. -3 The storage modulus of elasticity at vibration frequencies of Hz is 12.0 to 18.0 MPa. In pulsed NMR measurements of samples taken from the elastic member at 50°C, a spin-spin relaxation time T2 exists. L Chain segments ranging from 250 to 360 μs, The polyurethane includes a polyurethane elastomer. The polyurethane elastomer comprises polysiloxane segments having a structure represented by the following formula (1). The polysiloxane segments are bonded to the polyurethane elastomer containing a polyurethane backbone, and The number I of the structures represented by formula (1) for each of the polysiloxane segments is from 7 to 195:

2. The electrophotographic cleaning scraper according to claim 1, The polysiloxane segments thereon are bonded to the polyurethane backbone via a structure represented by the following formula (2), and The number m of structures represented by equation (2) for each of the polysiloxane segments is 1 to 10: In equation (2), n is an integer from 1 to 5, and "*" indicates the bonding part with the polyurethane skeleton.

3. The electrophotographic cleaning scraper according to claim 1 or 2, in, In pulsed NMR measurements of samples taken from the elastic member at 50°C, a spin-spin relaxation time T2 exists. L The segments range from 250 μs to 320 μs.

4. The electrophotographic cleaning scraper according to claim 2, Where m is an integer from 2 to 10.

5. The electrophotographic cleaning scraper according to claim 1 or 2, The polyurethane elastomer contains 0.5 to 15% by mass of the structure represented by formula (1).

6. The electrophotographic cleaning scraper according to claim 1 or 2, The polysiloxane segments therein have a structure in which a polysiloxane having a structure represented by the following formula (3) forms a urethane ester: In equation (3), I and m are the average number of moles added, where I is from 7 to 195, m is from 1 to 10, and n is an integer from 1 to 5. The siloxane structure is represented by -O-Si(CH3)2- and the structure is represented by -O-Si(CH3)((CH2)2-. n The structure represented by OH)- can be arranged in block copolymer or random copolymer.

7. The electrophotographic cleaning scraper according to claim 1 or 2, in, In the FT-IR measurement of the elastic component using diamond as the ATR crystal, 1,415cm -1 Peak intensity at 1,538 cm⁻¹ -1 The ratio of peak intensities at each location ranges from 0.50 to 0.

65.

8. The electrophotographic cleaning scraper according to claim 1 or 2, in, When the side of the electrophotographic cleaning blade that contacts the surface of the component being cleaned is defined as the front end side of the electrophotographic cleaning blade, The elastic member is plate-shaped, and the plate shape has at least a main surface facing the member being cleaned and a front surface that forms the front edge together with the main surface on the front end side. Suppose a third line segment is drawn on the front end surface, parallel to the front end side edge and 0.5mm away from the front end side edge. Let the length of the third line segment be L', and let the points on the third line segment that are 1 / 8L', 1 / 2L', and 7 / 8L' away from one end be P0', P1', and P2', respectively. Samples taken at each of P0', P1', and P2' were heated and vaporized in an ionization chamber, and heated to 1,000°C at a heating rate of 10°C / s using a direct sample introduction mass spectrometer that ionizes sample molecules. The detected amounts of all ions obtained are denoted as M1, and When the integrated intensity of the peak corresponding to the m / z value in the range of 380.5 to 381.5 of the extracted ion thermogram is expressed as M2, M2 / M1 is less than 0.0010.

9. A processing box comprising an electrophotographic cleaning scraper according to any one of claims 1 to 8 and a component to be cleaned.

10. An electrophotographic image forming apparatus comprising an electrophotographic cleaning blade and a cleaning component according to any one of claims 1 to 8.

11. A urethane molded article comprising polyurethane, The polyurethane described therein, in an environment of 24°C, has a content of 1×10 -3 The storage modulus of elasticity at vibration frequencies of Hz is 12.0 to 18.0 MPa. In pulsed NMR measurements of samples taken from the urethane molded body at 50°C, a spin-spin relaxation time T2 was observed. L Chain segments ranging from 250 to 360 μs, The polyurethane includes a polyurethane elastomer. The polyurethane elastomer comprises polysiloxane segments having a structure represented by the following formula (1). The polysiloxane segments are bonded to the polyurethane elastomer containing a polyurethane backbone, and The number I of the structures represented by formula (1) for each of the polysiloxane segments is from 7 to 195:

12. The urethane molded article according to claim 11, The polysiloxane segments thereon are bonded to the polyurethane backbone via a structure represented by the following formula (2), and The number m of structures represented by equation (2) for each of the polysiloxane segments is 1 to 10: In equation (2), n is an integer from 1 to 5, and "*" indicates the bonding part with the polyurethane skeleton.

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