Cleaning blade for electrophotography, process cartridge, and electrophotographic image forming apparatus

Abstract

The present invention relates to a cleaning blade for electrophotography, a process cartridge, and an electrophotographic image forming apparatus. A cleaning blade is provided, comprising: an elastic member comprising polyurethane; and a supporting member configured to support the elastic member. The polyurethane has a structure consisting of -(CH2) m The elastic member has a plate shape and has a main surface and a front end surface forming a front end edge with the main surface at least on the front end side. The Martens hardness at each position at intervals of 30 μm from the front end edge to a position 100 μm away from the front end edge decreases from the front end edge to the position. The Martens hardness HM1 of the elastic member at position P1 is 1.0 N / mm 2 The elastic layer satisfies Kω1>Kω2>Kω3. Furthermore, the erosion rate E of the cleaning blade is 0.6 μm / g or less.

Description

Technical Field

[0001] The present disclosure relates to a cleaning blade for electrophotography, a process cartridge, and an electrophotographic image forming apparatus. Background Art

[0002] In electrophotographic image forming apparatuses, a cleaning blade is provided to remove toner remaining on an image bearing member such as a photosensitive drum, a transfer belt, or an intermediate transfer member. A cleaning blade comprising a thermosetting polyurethane elastomer, at least in the portion contacting the image bearing member, is commonly used. This is because thermosetting polyurethane elastomers are plastically deformable and have excellent wear resistance.

[0003] In recent years, the demand for further improvement in the image quality of electrophotographic images has driven a drive to further reduce the particle size of toners. Consequently, there is a need to further improve the cleaning performance of cleaning blades used to remove toner remaining on image-bearing members, thereby enabling the stable removal of even small-particle toners. To this end, for example, it has been proposed to increase the hardness of the contact portion of the cleaning blade to increase the contact pressure against the image-bearing member being cleaned. When the hardness of the contact portion is increased, the contact width with the image-bearing member can be reduced. As a result, the contact pressure can be increased, thereby improving the cleaning performance of small-particle toners.

[0004] Japanese Patent Application Laid-Open No. 2010-134310 proposes a cleaning blade in which the hardness of the abutment portion is improved while the interior of the cleaning blade is kept soft by impregnating polyurethane rubber with an isocyanate compound from its surface and reacting the polyurethane rubber and the isocyanate compound with each other.

[0005] However, when the cleaning blade according to Japanese Patent Application Laid-Open No. 2010-134310 is used for a long period of time, fine chipping may occur in its contact portion. As a result, its contact state with the member serving as the contact object (the member to be cleaned) may become unstable, causing toner to escape, resulting in the appearance of streaked images in some cases. Summary of the Invention

[0006] At least one aspect of the present disclosure is to provide a cleaning blade for electrophotography that stably exhibits excellent cleaning performance even when used for a long period of time.

[0007] In addition, another aspect of the present disclosure is directed to providing a process cartridge and an electrophotographic image forming apparatus each including the above-described cleaning blade.

[0008] According to one aspect of the present disclosure, there is provided an electrophotographic cleaning blade comprising: an elastic member comprising polyurethane; and a supporting member configured to support the elastic member, wherein the electrophotographic cleaning blade is configured to clean the surface of a moving member by causing a portion of the elastic member to abut against the surface of the member. The polyurethane has a structure consisting of -(CH2) m -, wherein "m" represents an integer greater than or equal to 4. When the side of the cleaning blade that comes into contact with the surface of the member to be cleaned is defined as the front end side of the cleaning blade, the elastic member has a plate shape having, at least on the front end side, a main surface facing the member to be cleaned and a front end surface forming a front end side edge with the main surface. When a first line segment is drawn on the front end surface so that the first line segment is parallel to the front end side edge at a distance of 10 μm from the front end side edge, and when: the length of the first line segment is represented by L; a point on the first line segment that is 1 / 2L away from one end side of the length direction of the elastic member is represented by P1; the Martens hardness of the elastic member measured at the position of point P1 is represented by HM1; and on a cross section of the elastic member that is perpendicular to the front end surface containing point P1 and the front end side edge, a bisector of the angle formed by the main surface and the front end surface is drawn, and the Martens hardness at each position on the bisector with an interval of 30 μm from the front end side edge to the position 100 μm farthest from the front end side edge is measured, the Martens hardness at each position decreases from the front end side edge to the position 100 μm farthest from the front end side edge, and HM1 is 1.0 N / mm 2 Furthermore, regarding the scattering curve obtained by causing the characteristic X-ray from the Cu tube ball to enter the evaluated surface area of the cleaning blade including the point P1 at an incident angle ω, the index value Kω determined by the following formula (1): satisfies Kω1>Kω2>Kω3, where Kω1 represents the index value when ω1=0.5°, Kω2 represents the index value when ω2=1.0°, and Kω3 represents the index value when ω3=3.0°:

[0009] Kω=[I c / (I c +I a )]×100 (1)

[0010] Among them I c Indicates the peak area value at 2θ = 21.0° in the scattering curve, I a It represents the peak area value at 2θ=20.2° in the scattering curve, and wherein the erosion rate E of the cleaning blade measured on the evaluated surface area using spherical aluminum oxide particles having an average particle size (D50) of 3.0 μm is 0.6 μm / g or less.

[0011] In addition, according to another aspect of the present disclosure, there is provided a process cartridge including a cleaning blade for electrophotography.

[0012] Furthermore, according to another aspect of the present disclosure, there is provided an electrophotographic image forming apparatus including the electrophotographic cleaning blade.

[0013] Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic perspective view of a cleaning blade for electrophotography according to one aspect of the present disclosure.

[0015] Figure 2 It is a diagram for illustrating a state in which the edge of the cleaning blade abuts against the member to be cleaned when the process cartridge is stationary.

[0016] Figure 3 1 is a diagram for illustrating a line segment drawn on the front end surface of the elastic member parallel to the front end edge at a distance of 10 μm from the front end edge.

[0017] Figure 4 Graphs showing measurement positions of grazing incidence X-ray diffraction, Martens hardness, and erosion rate.

[0018] Figure 5 A diagram showing positions at which Martens hardness is measured.

[0019] Figure 6 It is a graph for illustrating the measurement method of the erosion rate.

[0020] Figure 7 is a measurement method used to show edge chipping. DETAILED DESCRIPTION

[0021] In the present disclosure, unless otherwise stated, the description "XX to YY" indicating a numerical range refers to a numerical range including the lower limit and the upper limit as endpoints. In addition, when describing a numerical range in a segmented manner, the upper limit and the lower limit of each numerical range can be arbitrarily combined.

[0022] As a member to be cleaned to which the cleaning blade for electrophotography according to one aspect of the present disclosure (hereinafter sometimes referred to simply as a "cleaning blade") is applied, for example, an image bearing member such as a photosensitive member and an endless belt such as an intermediate transfer belt are given. Below, a cleaning blade according to an embodiment of one aspect of the present disclosure will be described in detail, taking the case where the member to be cleaned is an image bearing member as an example. The present disclosure is not limited to the example in which the member to be cleaned is an image bearing member.

[0023] <Composition of Cleaning Blade>

[0024] Figure 11 is a schematic perspective view of a cleaning blade 1 according to one aspect of the present disclosure. The cleaning blade 1 includes an elastic member 2 and a supporting member 3 configured to support the elastic member 2.

[0025] Figure 2 The present invention schematically illustrates an example of a cross-sectional state in which a cleaning scraper according to one aspect of the present disclosure contacts a member to be cleaned. The elastic member 2 is in the shape of a plate having a main surface 4 and a front end surface 5. The main surface 4 is the surface facing the member to be cleaned 6. The front end surface 5 is the surface that forms a front end side edge with the main surface 4 on the front end side when the side of the cleaning scraper that contacts the surface of the member to be cleaned 6 is defined as the front end side. R represents the rotational direction of the member to be cleaned. A portion of the elastic member 2 is brought into contact with the surface of the moving member to be cleaned 6 to clean the surface of the member to be cleaned 6.

[0026] The present inventors have found that, for example, the cleaning blade of the following aspect has excellent chipping resistance and keeps exhibiting excellent cleaning performance even when used for a long period of time.

[0027] That is, a cleaning blade according to one aspect of the present disclosure includes an elastic member including polyurethane, and a supporting member configured to support the elastic member.

[0028] Polyurethane has -(CH2) m -, wherein "m" represents an integer of 4 or greater.

[0029] The side of the cleaning blade that contacts the surface of the member to be cleaned is defined as the front end side of the cleaning blade, and it is assumed that a first line segment is drawn on the front end surface of the elastic member so that the first line segment is parallel to the front end side edge at a distance of 10 μm from the front end side edge.

[0030] In addition, when: the length of the first line segment is represented by L; the point on the first line segment that is 1 / 2L away from one end side of the length direction of the elastic member is represented by P1; the Martens hardness of the elastic member measured at the position of point P1 is represented by HM1; and on a cross section of the elastic member that is perpendicular to the front end face containing point P1 and the front end side edge, a bisector of the angle formed by the main surface and the front end face is drawn, and the Martens hardness at each position on the bisector from the front end side edge to the position 100 μm farthest from the front end side edge at intervals of 30 μm is measured, the Martens hardness at each position gradually decreases from the front end side edge to the position 100 μm farthest from the front end side edge.

[0031] In addition, HM1 is 1.0N / mm 2 above.

[0032] Furthermore, regarding the index value Kω determined by the following formula (1) from the scattering curve obtained by causing the characteristic X-ray from the Cu tube ball to enter the evaluated surface area of the cleaning blade including the point P1 at the incident angle ω: Kω1>Kω2>Kω3 is satisfied, where Kω1 represents the index value when ω1=0.5°, Kω2 represents the index value when ω2=1.0°, and Kω3 represents the index value when ω3=3.0°:

[0033] Kω=[I c / (I c +I a )]×100 (1)

[0034] Among them I c represents the peak area value at 2θ = 21.0° in the scattering curve, and I a It represents the peak area value at 2θ=20.2° in the scattering curve.

[0035] Furthermore, the erosion rate E of the cleaning blade measured on the surface area to be evaluated using spherical aluminum oxide particles having an average particle size (D50) of 3.0 μm was 0.6 μm / g or less.

[0036] The hardness of the elastic member gradually decreases as the distance from its surface increases. Therefore, the stress caused by the abutment can be dispersed. In addition, there is no interface such as a boundary between the high-hardness layer and the non-hardness layer inside the elastic member, so interlayer peeling does not occur. In addition, compared with the outermost surface, the inner part has a lower hardness. Therefore, compared with the case where the inner part also has a high hardness like the outermost surface, it has better followability to the surface of the image bearing member, and thus can exhibit excellent cleaning performance.

[0037] The Martens hardness of the outermost surface of the elastic member is preferably 1.0 to 5.0 N / mm 2 When the Martens hardness of the outermost surface is 1.0N / mm 2 When the elastic member is above 5.0 N / mm, the elastic member can abut against the photosensitive drum with a high abutting pressure, and when the Martens hardness is 5.0 N / mm 2 When the elastic member is used for a long time, it can softly contact the photosensitive drum even when stripe-shaped concave and convex parts are formed on the photosensitive drum. As a result, the occurrence of poor cleaning can be suppressed.

[0038] The erosion rate E is calculated using a microparticle spray erosion (MSE) test. The MSE test involves pulse-jetting fine particles, each with a diameter roughly the same as the toner, onto a cleaning blade. The erosion rate is calculated based on the depth of erosion of the cleaning blade at the sprayed portion and the amount of fine particles sprayed. The erosion rate E represents the depth of erosion per unit amount sprayed and is a parameter that indicates the fragility of the object being evaluated. Specifically, a larger erosion rate E indicates a more brittle object. Therefore, cleaning blades with a large erosion rate E are prone to micro-fracture during long-term use.

[0039] Typically, polyurethane tends to become more brittle as its hardness increases. However, the elastic member according to the present disclosure, while having increased hardness compared to the related art, has a small parameter indicating brittleness calculated by the MSE test. In other words, the elastic member, despite its high hardness, is not brittle.

[0040] In addition, the MSE test allows for the hypothetical measurement of the accelerated durability performance of a cleaning blade in an electrophotographic device. When the erosion rate E measured using spherical alumina particles having an average particle size (D50) of 3.0 μm is 0.6 μm / g or less, the cleaning blade has sufficient strength required for a cleaning blade. That is, brittle fracture rarely occurs. Therefore, even with long-term use, the occurrence of chipping is reduced, and thus, the occurrence of poor cleaning caused by chipping can be suppressed. When the erosion rate E is 0.6 μm / g or less, even with long-term use, fine chipping rarely occurs on the surface of the blade. In addition, an erosion rate E of 0.5 μm / g or less is more preferred because the cleaning blade has strong wear resistance and can suppress the occurrence of fine chipping.

[0041] The MSE test can be performed using, for example, an MSE-A type tester (Palmeso Co., Ltd.).

[0042] Next, the index value Kω is a value calculated by the grazing incidence X-ray method described below. According to the grazing incidence X-ray method, by measuring while slightly changing the incident angle of the X-ray, information on sites at different depths from the surface can be obtained, and information on deeper parts can be obtained by increasing the incident angle. When the measurement is performed when the incident angle changes from 0.5° to 3°, structural information with a depth of 10 to 65 μm can be obtained using characteristic X-rays from the Cu tube ball. Using the structural information obtained at each depth, the index value Kω of crystallinity is calculated from the area ratio between the crystalline peak and the non-crystalline peak. The larger the Kω, the higher the crystallinity (the greater the amount of crystalline component).

[0043] The elastic member according to the present disclosure satisfies Kω1>Kω2>Kω3, where Kω1, Kω2, and Kω3 represent respective K values calculated when the incident angles are set to ω1=0.5°, ω2=1°, and ω3=3°, respectively, with respect to the index value Kω determined by equation (1) from a scattering curve obtained by causing characteristic X-rays from a Cu tube ball to enter the surface region being evaluated at an incident angle ω. This indicates that the elastic member is in a state in which the crystallinity is highest at the outermost surface and the crystallinity gradually decreases toward the inside (in the depth direction from the surface).

[0044] By being in a state where the crystallinity gradually decreases toward the inner side, the elastic member realizes a structure in which the surface is moderately hard while the inner part remains soft.

[0045] The various physical properties of the elastic member described above can be conceivably exhibited because the polyurethane contained in the elastic member has a structure consisting of -(CH2) m The polyol preferably has a crystalline structure by orienting the main chain portion of the polyol having a linear portion represented by - ("m" represents an integer of 4 or greater). The polyol used as a raw material preferably has a repeating structural unit represented by the following chemical formula (1), and the obtained polyurethane also preferably has a structure represented by the following chemical formula (1).

[0046] Polyurethane having such a repeating structural unit can be more easily crystallized by the intermolecular force acting between the R1 and R2 moieties in the adjacent polyol structures. The polyurethane preferably has two or more structural units each represented by the following chemical formula (1).

[0047]

[0048] In the chemical formula (1), R1 and R2 each represent a linear divalent hydrocarbon group having 4 to 10 carbon atoms, and R1 and R2 may be the same as or different from each other. "n" represents an integer of 1 or greater.

[0049] In the elastic member according to the present disclosure, due to the -(CH2) m The crystal structure formed by the orientation of the main chain portion of the polyol of - ("m" represents an integer greater than or equal to 4) is more developed on the surface side. In other words, the degree of development of the crystal structure decreases from the surface side toward the inside.

[0050] The more developed the crystal structure is, the higher the hardness is, and as the degree of development of the crystal structure becomes less, the hardness becomes lower. In addition, in the elastic member according to the present disclosure, the degree of development of the crystal structure becomes less from the surface toward the inside, and therefore, the hardness decreases continuously from the surface toward the inside. Therefore, the cleaning blade according to the present disclosure can simultaneously achieve both a high abutment pressure on the image bearing member and excellent followability to the image bearing member. As a result, the cleaning blade according to the present disclosure hardly causes poor cleaning. In addition, in the elastic member according to the present disclosure, unlike the cleaning blade having a multilayer structure formed of a low hardness layer and a high hardness layer, there is no interface between the low hardness layer and the high hardness layer in the interior, and therefore, interlayer peeling does not occur even when used for a long time.

[0051] In addition, in the solidified layer formed by impregnation with an isocyanate compound disclosed in Japanese Patent Application Laid-Open No. 2010-134310, there are aggregated hard segments. Therefore, when stress is applied to the cleaning blade including the solidified layer, the front end portion thereof may be broken due to the shedding of the hard segments. At the same time, in the elastic member according to the present disclosure, a high hardness region is formed because the polyurethane has a structure consisting of -(CH2) m The main chains of the polyol represented by - ("m" represents an integer of 4 or greater) are oriented by intermolecular forces. Therefore, the elastic member has excellent impact absorption and is less likely to break even during long-term use due to minor stresses applied by uneven hardness of the toner or photosensitive drum.

[0052] The structure of formula (1) can be determined using a mass spectrometer that involves a direct sample introduction system that ionizes the sample molecules.

[0053] Specifically, M2 / M1 is preferably 0.0001 to 0.1000, where M1 represents the amount of all ions detected when a sample to be sampled is heated in an ionization chamber to be vaporized and heated to 1,000° C. at a temperature increase rate of 10° C. / s by a mass spectrometer using a direct sample introduction system that ionizes sample molecules, and M2 represents the integrated intensity of the peak of the extracted ion thermogram corresponding to the m / z value derived from the chemical formula (1). When the structure of the chemical formula (1) is included in this range, the crystal structure of the surface can be formed more reliably.

[0054] [Elastic member]

[0055] The polyurethane (polyurethane elastomer) used to form the elastic member according to the present disclosure is mainly obtained from raw materials such as polyisocyanate, polyol, chain extender, catalyst and other additives. These components will be described in detail below.

[0056] <Polyisocyanate>

[0057] Examples of the polyisocyanate used may include a mixture containing 4,4′-diphenylmethane diisocyanate (MDI) trimer as a main component, a mixture of 1,5-pentamethylene diisocyanate trimer (isocyanurate form), xylylene diisocyanate trimer (isocyanurate form) and xylylene diisocyanate monomer, 4,4′-diphenylmethane diisocyanate (MDI), 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate, ... ester (2,6-TDI), xylylene 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), tetramethylxylylene diisocyanate (TMXDI), carbodiimide-modified MDI, and polymethylene phenyl polyisocyanate (PAPI).

[0058] The above-mentioned polyisocyanates can be used alone or in combination. In addition, before use, the polyisocyanates can be reacted with any of various polyols to convert them into prepolymers. Among them, a mixture of xylylene diisocyanate trimer (isocyanurate form) and xylylene diisocyanate monomer is preferably used because of its excellent mechanical properties. Such mixtures can be used alone or in combination.

[0059] When the hard segments crystallize, while hardness increases, brittleness tends to decrease. Therefore, to maintain proper hard segment formation, the type and amount of isocyanate should be adjusted to achieve an appropriate amount of chemical bonding. Trimeric isocyanates are particularly preferred because the presence of branched or strained structures in the backbone can reduce hard segment formation.

[0060] <Polyol>

[0061] Examples of the polyol may include polyester polyol, polyether polyol, caprolactone polyol, polycarbonate polyol, and silicone polyol, and a specific example thereof is polyester polyol.

[0062] In order to obtain the effects of the present disclosure, it is necessary that the crystal structure gradually decays from the surface toward the inside. Therefore, the polyester polyol is preferably a polyester polyol that is solid (crystalline) at room temperature, has a structural unit represented by the following chemical formula (1), has a linear alkyl chain, and has a crystallization temperature of 0 to 150°C.

[0063]

[0064] In the chemical formula (1), R1 and R2 each independently represent a linear divalent hydrocarbon group having 4 to 10 carbon atoms, and "n" represents an integer of 1 or greater.

[0065] From the viewpoint of production and crystal structure characteristics, it is preferred to use two or more polyester polyols in which R1 and R2 are different from each other. In addition, the polyester polyol may contain a linear divalent hydrocarbon group having 2 or 3 carbon atoms.

[0066] The number average molecular weight of this polyester polyol as a whole is preferably 400 to 10,000, particularly preferably 800 to 4,000. A number average molecular weight of 800 or more is particularly preferred because the hardness and chipping resistance of the polyurethane obtained by crystallization of the main chain of the polyol are satisfactory, and a number average molecular weight of 4,000 or less is particularly preferred because the polyester polyol has an appropriate viscosity when used under heating, thereby excelling in handling and providing satisfactory hardness.

[0067] When R1 and R2 in the chemical formula (1) each have 3 or fewer carbon atoms, crystallization hardly proceeds, and thus, it is difficult to improve the surface hardness. In addition, when R1 and R2 each have 11 or more carbon atoms, there is a tendency for excessive crystallization to occur, thereby reducing brittleness.

[0068] At the same time, when R1 and R2 each represent a linear divalent hydrocarbon group having 4 to 10 carbon atoms, the crystal structure formed by the orientation of the main chain portion of the polyol has high hardness, and the hardness decreases as the crystal structure disappears. Therefore, as the crystal structure decays from the surface toward the interior, the hardness can be continuously reduced from the surface toward the interior. Therefore, the cleaning blade according to the present disclosure can increase the abutment pressure against the image bearing member. In addition, it can even enhance the ability to follow the shape of the image bearing member.

[0069] The structure represented by chemical formula (1) can be used alone. However, when the asymmetry of the crystal structure is increased, a structure with better impact resistance can be formed, and a cured layer with better crack resistance can be formed. Therefore, it is preferable to combine two or more polyester polyols each having a linear alkyl chain with 4 to 10 carbon atoms.

[0070] Furthermore, the case where the following first polyester polyol and the following second polyester polyol are used in combination is preferable because the interaction between crystal structures is promoted to further improve impact resistance.

[0071] • First polyester polyol: a polyester polyol having a linear alkyl chain having 4 to 6 carbon atoms.

[0072] Second polyester polyol: a polyester polyol having both a linear alkyl chain having 7 to 10 carbon atoms and a linear alkyl chain having 4 to 6 carbon atoms.

[0073] Examples of suitable polyester polyols include NIPPOLLAN (registered trademark) 164 (manufactured by Tosoh Corporation), NIPPOLLAN (registered trademark) 4073 (manufactured by Tosoh Corporation), NIPPOLLAN (registered trademark) 136 (manufactured by Tosoh Corporation), NIPPOLLAN (registered trademark) 4009 (manufactured by Tosoh Corporation), NIPPOLLAN (registered trademark) 4010 (manufactured by Tosoh Corporation), NIPPOLLAN (registered trademark) 3027 (manufactured by Tosoh Corporation), POLYLITE (registered trademark) OD-X-2555 (manufactured by DIC Corporation), POLYLITE (registered trademark) OD-X-2523 (manufactured by DIC Corporation), and ETERNACOLL (registered trademark) 3000 series (manufactured by Ube Industries, Ltd.).

[0074] The structure of formula (1) can be determined using a mass spectrometer that involves a direct sample introduction system that ionizes the sample molecules.

[0075] Specifically, M2 / Ml is preferably 0.0001 to 0.1000, where Ml represents the amount of all ions detected when the sample to be sampled is heated in an ionization chamber to be vaporized and heated to 1,000°C at a heating rate of 10°C / s by using a mass spectrometer that uses a direct sample introduction system that ionizes the sample molecules, and M2 represents the integrated intensity of the peak of the extracted ion thermogram corresponding to the m / z value derived from the chemical formula (1).

[0076] When the structure of the chemical formula (1) is contained within this range, the surface can be crystallized while suppressing the occurrence of insufficient curing.

[0077] When polyurethane is produced from polyester polyol and isocyanate compounds, urethane bonds are formed by the reaction between the terminal of the polyester polyol and the isocyanate. As a result, hard segments are sometimes generated by hydrogen bonding of the urethane bonds, and the crystalline polyester polyol cannot be fully moved, resulting in insufficient toughness in some cases.

[0078] In view of the above, a polyrotaxane having hydroxyl groups can be included as a polyol component. Among them, polyrotaxanes containing two or more hydroxyl groups in one molecule are preferred. Polyrotaxanes having hydroxyl groups introduced at the end of the side chain of the cyclic molecule are particularly preferred.

[0079] Polyrotaxanes have a structure in which linear molecules penetrate a large number of cyclic molecules, and the cyclic molecules can move freely on the linear molecules. Therefore, polyrotaxanes have a structure in which end-capping groups are bonded to both ends of the linear molecules to prevent the cyclic molecules from detaching from the linear molecules. The cyclic molecules each have a hydroxyl group, so the polyester polyol ends are bonded via an isocyanate compound. As a result, the addition of polyrotaxanes significantly improves the range of movement of the crystalline polyester polyol during deformation. Therefore, fracture during deformation can be effectively suppressed, and the toughness improvement effect is promoted.

[0080] In addition, when a polyrotaxane is added to form a m In the case of a linear urethane structure represented by - ("m" represents an integer of 4 or greater), improvement in toughness can be expected due to crystallization of the linear structure portion.

[0081] An example of the polyrotaxane is "SeRM (registered trademark) Super Polymer" commercially available from Advanced Softmaterials Inc. In this embodiment, the polyrotaxane having a hydroxyl group introduced at the terminal of the side chain of the cyclic molecule is preferably used.

[0082] <Chain Extender>

[0083] For example, glycols are used as chain extenders. Examples of such glycols may 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, benzyl alcohol (p-phenylenediol), and triethylene glycol. In addition, in addition to the above glycols, other polyols may also be used, and examples thereof may include trimethylolpropane, glycerol, pentaerythritol, and sorbitol. These chain extenders may be used alone or in combination.

[0084] <Catalyst>

[0085] As the catalyst, a catalyst commonly used for curing polyurethane elastomers can be used. Examples thereof include tertiary amine catalysts, and specific examples thereof include: dibutyltin dilaurate; amino alcohols such as dimethylethanolamine and N,N,N'-trimethylaminopropylethanolamine; trialkylamines such as triethylamine; tetraalkyldiamines such as N,N,N',N'-tetramethyl-1,3-butanediamine; triethylenediamine, piperazine-based compounds, and triazine-based compounds.

[0086] Alternatively, an organic acid salt of an alkali metal, such as potassium acetate or potassium octoate, may be used. Furthermore, a metal catalyst commonly used for carbamate formation, such as dibutyltin dilaurate, may also be used. These catalysts may be used alone or in combination.

[0087] Additives such as a pigment, a plasticizer, a water-repellent, an antioxidant, an ultraviolet absorber, and a light stabilizer may be further blended as needed.

[0088] [Supporting member]

[0089] There is no particular limitation on the material of the support member for forming the cleaning blade of the present disclosure, and the support member can be made of, for example, a metal material such as a steel plate, a stainless steel plate, a zinc chromate coated steel plate, or a chromium-free steel plate, or a resin material such as 6-nylon or 6,6-nylon.

[0090] In addition, the method of bonding the support member 3 and the elastic member 2 to each other is not particularly limited, and an appropriate method can be selected from known methods. An example thereof may be a method involving bonding the members to each other using an adhesive such as a phenolic resin.

[0091] <Production Method of Cleaning Blade>

[0092] As a production method of a cleaning blade according to the present disclosure, there is given a method involving producing an elastic member by using the above-mentioned polyol in such a manner as to satisfy the following curing conditions.

[0093] [Curing conditions]

[0094] Typically, to ensure that the urethanization reaction proceeds reliably and fully cures the polyurethane, temperature and time are controlled. Furthermore, in the present disclosure, the following curing conditions are employed to prevent the reduction in brittleness associated with increased hardness, a problem with polyurethanes in the prior art. The curing conditions are described in detail below.

[0095] In the production of polyurethane in the prior art, polyurethane is cured by heating until cross-linking is complete, and then matured in a predetermined atmosphere. On the other hand, in the production of the elastic member according to the present disclosure, curing is terminated before cross-linking of the polyurethane is complete, and then the polyurethane is secondary cured by maturing in an atmosphere at a temperature below the crystallization temperature of the polyol.

[0096] In a semi-cured polyurethane obtained by terminating the curing reaction before crosslinking of the polyurethane is complete, unreacted polyols remain in a state with high molecular mobility. While maintaining this state, the semi-cured polyurethane is subjected to secondary curing in an atmosphere below the crystallization temperature of the polyols. Consequently, a temperature gradient forms from the surface of the semi-cured polyurethane toward its interior. Consequently, the surface of the semi-cured polyurethane cools rapidly due to exposure to this atmosphere, and crystallization of the remaining polyol backbone proceeds. Simultaneously, cooling within the semi-cured polyurethane due to exposure to this atmosphere is delayed compared to the surface, causing crosslinking of the polyurethane to proceed and not allowing significant crystallization of the polyols to proceed. As a result, a structure is formed in which the amount of crystallized polyols gradually decreases from the surface toward the interior. Due to the crystallization of the polyol backbone, the hardness of the resulting elastic member increases near the surface. On the other hand, the hardness within the interior is low because crystallization of the polyols has not progressed relatively smoothly. Consequently, the Martens hardness gradually decreases from the surface toward the interior.

[0097] When polyurethane is cured until crosslinking is complete, as in conventional techniques, the crosslinking structure of the polyurethane is fully developed. Therefore, even if unreacted polyol remains, its molecular mobility is low. Therefore, even if the polyol is subsequently aged at a temperature below the crystallization temperature of the polyol, the main chain of the polyol is hardly oriented, and surface crystallization hardly progresses.

[0098] Furthermore, when the curing reaction is terminated with incomplete polyurethane crosslinking and then aging is performed in an atmosphere above the crystallization temperature of the polyol, the main chain of the polyol does not crystallize, and polyurethane crosslinking proceeds only on the surface. Consequently, it is difficult to increase the Martens hardness of the resulting polyurethane surface.

[0099] In the present disclosure, the urethane undergoes chemical crosslinking, albeit incompletely, during the primary curing process. Consequently, the surface after the secondary curing exhibits a structure in which the crystalline structure of the polyol backbone and the chemical crosslinking of the urethane coexist. If only the crystalline structure of the polyol backbone exists on the surface, the Martens hardness of the surface is excessively high. Consequently, during long-term use, the cleaning blade cannot softly contact the photosensitive drum, which has streaked irregularities formed on its surface, resulting in poor cleaning.

[0100] The crystallization of a polyol can be regulated based on the extent of chemical crosslinking of the carbamate during primary curing, as well as the difference between the ambient temperature during secondary curing and the crystallization temperature of the polyol. Since chemical crosslinking of the carbamate is reduced during primary curing, the molecular mobility of the polyol increases after primary curing, promoting surface crystallization and making it easier for crystallization to reach deeper into the interior. Furthermore, as the difference between the ambient temperature during secondary curing and the crystallization temperature of the polyol increases, crystallization proceeds more easily, promoting both surface and internal crystallization.

[0101] The cleaning blade in which the elastic member and the supporting member are integrated can be obtained by placing the supporting member in a mold for a cleaning blade, then pouring the above-mentioned polyurethane raw material composition into the mold, and performing primary curing and secondary curing as described above.

[0102] Alternatively, the polyurethane elastomer sheet cured under production conditions satisfying the aforementioned curing conditions may be formed, cut into strips, and bonded to the support member. The bonding method may be selected from a method involving applying or pasting an adhesive to the support member and bonding the elastic member thereto; a method involving bonding the elastic member and the support member by stacking the elastic member and applying heat and pressure to the stacked body.

[0103] In addition, after secondary curing, cutting may be performed to adjust the shape of the edge of the cleaning blade so that it abuts against the image bearing member. When a polyurethane elastomer sheet is produced in advance and bonded to a supporting member, cutting may be performed before or after bonding.

[0104] <Process Cartridge and Electrophotographic Image Forming Apparatus>

[0105] The cleaning blade can be used by being incorporated into a process cartridge that is detachably mountable to the electrophotographic image forming apparatus.

[0106] Specifically, the cleaning blade according to the present disclosure can be used, for example, in a process cartridge including an image bearing member serving as a member to be cleaned and a cleaning blade configured to clean the surface of the image bearing member. Such a process cartridge contributes to stable formation of high-quality electrophotographic images.

[0107] In addition, an electrophotographic image forming apparatus according to one aspect of the present disclosure includes an image bearing member such as a photosensitive member and a cleaning blade configured to clean the surface of the image bearing member, and the cleaning blade according to the present disclosure can be used as the cleaning blade. Such an electrophotographic image forming apparatus can stably form high-quality electrophotographic images.

[0108] The present disclosure can provide a cleaning blade for electrophotography, which is obtained by m The crystal structure resulting from the orientation of the main chain portion of - ("m" represents an integer of 4 or greater) has excellent chipping resistance even during long-term use and can stably exhibit excellent cleaning performance.

[0109] According to another aspect of the present disclosure, a process cartridge that facilitates formation of high-quality electrophotographic images can be obtained. According to yet another aspect of the present disclosure, an electrophotographic image forming apparatus that can stably form high-quality electrophotographic images can be obtained.

[0110] Example

[0111] The present disclosure is described below by means of Production Examples, Examples, and Comparative Examples, but the present disclosure is by no means limited thereto. Reagents or industrial chemicals other than those shown in Examples and Comparative Examples were used as raw materials.

[0112] Polyisocyanate component

[0113] (1) A mixture of xylylene diisocyanate trimer (isocyanurate form) and xylylene diisocyanate monomer (molar ratio, trimer:monomer=1:1.2): Product name: "Takenate (registered trademark) XD-131R", manufactured by Mitsui Chemicals, Inc.

[0114] (2) A mixture containing 4,4′-diphenylmethane diisocyanate (MDI) trimer as a main component: Product name: "Millionate (registered trademark) MR-200", manufactured by Tosoh Corporation

[0115] (3) 1,5-Pentamethylene diisocyanate trimer (isocyanurate form): Product name: "STABiO (registered trademark) D-370N", manufactured by Mitsui Chemicals, Inc.

[0116] (4) Xylylenediisocyanate: Product name: "XDI", manufactured by Tokyo Chemical Industry Co., Ltd.

[0117] (5) 4,4′-diphenylmethane diisocyanate: Product name: "MDI", manufactured by Tosoh Corporation

[0118] Polyol components

[0119] (1) Polyester polyol: Product name: "NIPPOLLAN (registered trademark) 164", manufactured by Tosoh Corporation

[0120] In the chemical formula (1), the carbon numbers of R1 and R2 are 4 and 6, respectively.

[0121] (2) Polyester polyol: Product name: "NIPPOLLAN (registered trademark) 4009", manufactured by Tosoh Corporation

[0122] The carbon number of R1 and R2 in the chemical formula (1) is 4 each.

[0123] (3) Polyester polyol: Product name: "POLYLITE (registered trademark) OD-X-2555", manufactured by DIC Corporation

[0124] In the chemical formula (1), R1 and R2 have carbon numbers of 6 and 10, respectively.

[0125] (4) Polyrotaxane: Product name: "SH1300P-B", manufactured by ASM Inc.

[0126] Chain Extender

[0127] 1,4-Butanediol (1,4-BD): manufactured by Tokyo Chemical Industry Co., Ltd.

[0128] catalyst

[0129] (1) Dibutyltin dilaurate: manufactured by Tokyo Chemical Industry Co., Ltd.

[0130] (2) Tertiary amine catalyst: Product name: "RZETA (registered trademark)", manufactured by Tosoh Corporation

[0131] Preparation Example of Urethane Polymer

[0132] [Example 1]

[0133] The polyol component, chain extender, and urethanization catalyst were blended in the amounts shown in Table 1. Each component was dried by heating under reduced pressure as needed. The resulting liquid mixture was stirred under reduced pressure for 5 minutes to obtain a uniform solution containing the polyol as a main component.

[0134] A solution containing a polyol as a main component was blended with a polyisocyanate component in the mass shown in Table 1, and the mixture was stirred again for 3 minutes under reduced pressure, and then poured into a mold (thickness: 2 mm, height: 40 mm, width: 200 mm) heated to 130°C. Primary curing was performed for 3 minutes, and then the mold was quickly cooled to 25°C. The resultant was kept in the mold for 12 hours for secondary curing. Afterwards, the resultant was removed from the mold. Thus, an integral molded body 1 of polyurethane and a supporting member was obtained.

[0135] The mold used had a release agent applied thereto before the polyurethane elastomer composition was poured therein. A mixture of the following materials was used as the release agent.

[0136] ELEMENT14 PDMS 1000-JC (product name, manufactured by Momentive Performance Materials) 5.06 g

[0137] ELEMENT14 PDMS 10K-JC (product name, manufactured by Momentive Performance Materials) 6.19 g

[0138] SR1000 (product name, manufactured by Momentive Performance Materials) 3.75 g

[0139] EXXSOL (registered trademark) DSP145 / 160 (product name, manufactured by Exxon Mobil Corporation) 85g

[0140] The integrally formed body was appropriately cut to obtain a cleaning blade 1. The angle of its edge was set to 90°, and the distances in the short side direction, thickness direction, and long side direction of the polyurethane were set to 7.5 mm, 1.8 mm, and 240 mm, respectively. The obtained cleaning blade 1 was evaluated by the following method.

[0141] [Measurement method of polyol component]

[0142] The measurement of the polyol components was performed by a direct injection method (DI method) involving introducing a sample directly into an ion source without passing through a gas chromatograph (GC).

[0143] POLARIS Q manufactured by Thermo Fisher Scientific KK was used as an apparatus, and a direct exposure probe (DEP) was used.

[0144] Assume that a first line segment is drawn on the front end surface parallel to the front end side edge at a distance of 10 μm from the front end side edge, the length of the first line segment is represented by L, and polyurethane is scraped from point P1 on the first line segment at a distance of 1 / 2L from one end side using a biological cutter.

[0145] Approximately 0.1 μg of sample, taken at P1, was attached to a thin filament at the tip of the probe for direct insertion into the ionization chamber. The sample was then rapidly heated from room temperature to 1000°C at a constant heating rate (10°C / s) to vaporize it, and the resulting gas was detected by a mass spectrometer.

[0146] The detected amount M1 of all ions is defined as the sum of the integrated intensities of all peaks in the obtained total ion current thermogram. In addition, the detected amount M2 of the polyol component is defined as the integrated intensity within the m / z value range calculated by calculation formula (2).

[0147] Range of m / z values

[0148] {200+[14×(x-4)+14×(y-4)]+1}±0.5 Formula (2)

[0149] "x" and "y" represent the carbon numbers of R1 and R2, respectively, in the chemical formula (1).

[0150] In the present disclosure, the arithmetic mean value of the samples scraped from 5 sites starting from point P1 is used as the M2 / M1 value.

[0151] [Crystallinity Analysis]

[0152] The crystallinity was measured by grazing incidence X-ray diffraction (XRD) using an X-ray diffractometer (product name: ATX-G; manufactured by Rigaku Corporation).

[0153] The X-ray incident angles were set to ω1 = 0.5°, ω2 = 1°, and ω3 = 3°, and the crystal peak areas measured at each angle were set as I c1 , I c2 and I c3 , and the non-crystalline peak areas are set as I a1 , I a2 and I a3 As the X-ray incident angle becomes smaller, the display becomes closer to the surface side.

[0154] The measurement conditions are described below.

[0155] Tube: Cu (40kV, 20mA)

[0156] Slit condition: S2 (length: 1mm, width: 0.1mm)

[0157] RS, GS: On

[0158] Soller slit = 0.41

[0159] Origin 2016 (developer: OriginLab Corporation, USA) is used as software for peak area analysis. First, the background is determined and subtracted from the XRD pattern. Then, the peak is separated into a crystalline peak at 2θ = 21 ° and a peak derived from a non-crystalline component at 2θ = 20 °. When the position of the crystalline peak is fixed, and numerical constraints are imposed so that the integral value of each component takes a positive value and the half-peak width of each peak becomes an appropriate value, numerical fitting is implemented. The area value Ic of the crystalline peak is defined as the area value obtained by integrating the peak with a peak top at 2θ = 21 ° from the baseline in the region of 2θ = 13 ° to 30 ° when a baseline is drawn for 2θ = 3 to 40 °. The area value Ia of the non-crystalline peak is defined as the area value obtained by integrating the peak with a peak top at 2θ = 20.2 ° from the baseline in the region of 2θ = 13 ° to 30 ° when a baseline is drawn for 2θ = 3 to 40 °. I c1 and I a1 Substitute into the following formula (1) to obtain the crystallinity index Kω1. Similarly, I c2 and I a2 Substitute into the following formula (1) to obtain the index Kω2, and I c3 and I a3 Substitute into the following formula (1) to obtain the index Kω3.

[0160] Kω=[I c / (I c +I a )]×100 (1)

[0161] The crystallinity was evaluated by the evaluation criteria of whether the obtained Kω1, Kω2, and Kω3 satisfied the following relationship.

[0162] Crystallinity:

[0163] Y: satisfies the condition of Kω1>Kω2>Kω3

[0164] N: does not satisfy the situation where Kω1>Kω2>Kω3

[0165] When Kω1, Kω2, and Kω3 satisfy the relationship Kω1>Kω2>Kω3, the ratio of the crystallization peak at 2θ=21° decreases from the surface toward the inside. That is, the crystallinity decreases from the surface toward the inside of the cleaning blade.

[0166] like Figure 3 and Figure 4 As shown, it is assumed that a first line segment is drawn on the front end face 5 at a distance of 10 μm from the front end side edge and parallel to the front end side edge, the length of the first line segment is represented by L, and the measurement point is set at point P1 on the first line segment at a distance of 1 / 2L from one end side.

[0167] [Martens hardness]

[0168] Martens hardness was measured using a "Shimadzu Dynamic Ultra Microhardness Tester "DUH-W211S" manufactured by Shimadzu Corporation. The measurement environment was set to a temperature of 23° C. and a relative humidity of 55%. The indenter used was a triangular pyramid diamond indenter with an edge spacing of 115°, and the Martens hardness was determined by the following calculation formula (3).

[0169] Martens hardness: HM = α × P / D 2 Formula (3)

[0170] In formula (3), α represents a constant based on the shape of the indenter, P represents the test force (mN), and D represents the amount of indentation (indentation depth) (μm) of indentation into the sample. The measurement conditions are as follows.

[0171] α:3.8584

[0172] D: 2.0 μm

[0173] Load speed: 0.03mN / sec

[0174] Hold time: 5 seconds

[0175] Measuring point:

[0176] Assume that Figure 3 As shown, a first line segment is drawn parallel to the front end side edge at a distance of 10 μm from the front end side edge. Figure 4 As shown, when the length of the first line segment is represented by L and a point on the first line segment that is 1 / 2L away from one end side is represented by P1, the Martens hardness HM1 is measured at the position of P1.

[0177] In addition, if Figure 5 As shown, the angle θ formed by the main surface 4 and the front end surface is drawn on the cross section of the elastic member including P1 and perpendicular to the front end surface 5 and the front end side edge. 4-5 Then, the Martens hardness HM2, HM3 and HM4 were measured at respective positions (P2, P3 and P4) at 30 μm, 60 μm and 90 μm from the front end side edge on the bisector.

[0178] [Erosion rate E]

[0179] The erosion rate was measured using "MSE-A Type Tester" manufactured by Palmeso Co., Ltd.

[0180] Spherical alumina powder having an average particle size of 3.0 μm (product name: “AX3-15”, manufactured by Nippon Steel & Sumikin Materials Co., Ltd. Micron Co.) was dispersed in water to prepare a slurry containing 3% by mass of spherical alumina relative to the total mass of the slurry.

[0181] like Figure 6 As shown, the cleaning blade 63 is fixed on a table (not shown) so that the slurry 62 sprayed from the spray nozzle 61 is sprayed perpendicularly to the surface of the cleaning blade 63. The distance between the surface of the cleaning blade 63 and the lower end of the spray nozzle 61 is set to 4 mm, and the slurry 62 in which the spherical aluminum oxide 64 is dispersed in the water 65 is sprayed.

[0182] The measurement environment was set to a temperature of 23° C. and a relative humidity of 55%, the slurry jetting speed was set to 100 m / sec, and the cutting depth was measured using a probe-type surface shape measuring apparatus manufactured by Kosaka Laboratory Ltd. using a probe having a diamond needle with a tip radius R of 10 μm. The jetting conditions in this case were adjusted by the following method.

[0183] The slurry spraying conditions were pre-adjusted in the above-mentioned measurement environment using an existing hardness standard sheet (product name: "HRC-45", manufactured by Yamamoto Scientific Tool Laboratory Co., Ltd.) so that when 6.0 g of slurry was sprayed, a 6.0 μm cut was made. The erosion rate E in this case was 1.0 μm / g.

[0184] Assume that Figure 3 As shown, a first line segment is drawn parallel to the front end side edge at a distance of 10 μm from the front end side edge, as shown in FIG. Figure 4 As shown, the length of the first line segment is represented by L, and a point on the first line segment that is 1 / 2L away from one end side is represented by P1. The slurry is sprayed until a cutting depth of 20 μm is reached at P1, and the erosion rate E is determined from the amount of slurry used by using the following formula (3).

[0185] Erosion rate E (μm / g) = cutting depth (20 μm) / injection amount of spherical aluminum oxide particles (g) (3)

[0186] [Evaluation of cleaning performance]

[0187] The cleaning blade 1 was incorporated into a process cartridge of a color laser beam printer (product name; HP LaserJet Enterprise Color M553dn, manufactured by Hewlett-Packard Company) as a cleaning blade for a photosensitive drum serving as a member to be cleaned.

[0188] Then, under a normal temperature environment (temperature: 23° C., relative humidity: 55%), image formation was performed on 10,000 sheets, and then evaluation was performed (hereinafter referred to as “normal evaluation”).

[0189] Furthermore, the developing machine used was replaced with a developing machine in which the entire amount of toner cartridge had been replaced, and image formation was performed again on 10,000 sheets, followed by evaluation (hereinafter referred to as "double evaluation").

[0190] In addition, the evaluation was performed while the waste toner was appropriately sucked out through the hole opened at the back of the cartridge. With respect to the obtained images, the performance was rated by the following evaluation criteria.

[0191] Rank A: No image failure (streaks on the image) due to the cleaning blade occurred in both the normal evaluation and the double evaluation.

[0192] Rank B: Image failure (streaks on the image) due to the cleaning blade did not occur in the normal evaluation, and occurred to a very slight extent in the double evaluation (streaks with a streak length of 5 mm or less occurred on the image).

[0193] Rank C: Image failure (streaks on the image) due to the cleaning blade did not occur in the normal evaluation, but slightly occurred in the double evaluation (streaks with a length of more than 5 mm but 10 mm or less occurred on the image).

[0194] Rank D: Image failure (streaks on the image) due to the cleaning blade did not occur in the normal evaluation, but occurred in the double evaluation (streaks with a length of more than 10 mm occurred on the image).

[0195] Rank E: Image failure (streaks on the image) due to the cleaning blade occurred in both the normal evaluation and the double evaluation.

[0196] [Evaluation of edge chipping of cleaning blade]

[0197] After the above cleaning performance evaluation (2-fold evaluation) was completed, the cleaning blade was taken out from the box and observed at a magnification of 1,000 times with a digital microscope (product name: main body: VHX-5000, lens: VH-ZST, manufactured by Keyence Corporation).

[0198] like Figure 7As shown in FIG. 1 , the cleaning blade is placed under a digital microscope 7 with the support member 3 tilted at an angle of 45° relative to the horizontal direction so that the support member 3 faces upward and the front end surface 5 of the elastic member faces downward. Then, the entire longitudinal direction (length L) of the front end portion (the portion close to the front end surface 5) of the main surface 4 of the cleaning blade elastic member is observed.

[0199] like Figure 7 As shown in the partially enlarged view of the part, the maximum value of the distance in the short side direction of the edge chipping portion (the distance from the dotted line representing the main surface assuming that no chipping occurs) is measured as the "edge chipping amount" and evaluated according to the following standards.

[0200] Level A + : The edge fragmentation is less than 0.1μm.

[0201] Rank A: The amount of edge chipping is 0.1 μm or more and less than 0.5 μm.

[0202] Rank B: The amount of edge chipping is 0.5 μm or more and less than 1.0 μm.

[0203] Rank C: The amount of edge chipping is 1.0 μm or more and less than 3.0 μm.

[0204] Level C - : The edge chipping amount is 3.0 μm or more and less than 3.5 μm.

[0205] Grade D: The amount of edge chipping is 3.5 μm or more.

[0206] [Examples 2 to 12]

[0207] Cleaning blades 2 to 12 were obtained in the same manner as in Example 1, except that the blending and curing conditions were changed as shown in Table 1. The same evaluation as in Example 1 was performed, and the evaluation results are shown in Table 2A and Table 2B.

[0208] [Comparative Examples 1 and 2]

[0209] Cleaning blades 13 and 14 were obtained in the same manner as in Example 1, except that the blending and curing conditions were changed as shown in Table 1. The same evaluation as in Example 1 was performed, and the evaluation results are shown in Table 2B.

[0210] [Comparative Example 3]

[0211] Prepare the impregnant by mixing the following materials.

[0212] Polymeric MDI (product name: MR-100, manufactured by Nippon Polyurethane Industry Co., Ltd.) 10 g

[0213] Silicone resin (product name: MODIPER FS-700, manufactured by NOF Corporation) 2 g

[0214] 2-Butanone (manufactured by Tokyo Chemical Industry Co., Ltd.) 88 g

[0215] Cleaning Blade 8 obtained in the same manner as in Example 8 was immersed in the prepared impregnating agent for 180 seconds and then aged for 3 hours at 23°C and 55% relative humidity to obtain Cleaning Blade 15. The same evaluation as in Example 1 was performed and the evaluation results are shown in Table 2B.

[0216] Table 1

[0217]

[0218] Table 2A

[0219]

[0220] Table 2B

[0221]

[0222] While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the present disclosure is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A cleaning blade for electrophotography, characterized in that It includes: an elastic member comprising polyurethane; and a supporting member configured to support the elastic member, The electrophotographic cleaning blade is configured to clean the surface of the member being cleaned while the member is moving by causing a portion of the elastic member to abut against the surface of the member being cleaned. The polyurethane has -(CH2) m -, wherein "m" represents an integer greater than 4, wherein When the side of the cleaning blade that contacts the surface of the member to be cleaned is defined as the front end side of the cleaning blade, The elastic member has a plate shape and has, at least on the front end side, a main surface facing the member to be cleaned and a front end surface forming a front end side edge with the main surface. Assume that a first line segment is drawn on the front end surface so that the first line segment is parallel to the front end side edge at a distance of 10 μm from the front end side edge. When: The length of the first line segment is represented by L; A point on the first line segment that is 1 / 2L away from one end side of the elastic member in the longitudinal direction is represented by P1; The Martens hardness of the elastic member measured at the point P1 is denoted by HM1; and On a cross section of the elastic member perpendicular to the front end surface including the point P1 and the front end side edge, a line bisects the angle formed by the main surface and the front end surface, and the Martens hardness is measured at each position on the bisector at intervals of 30 μm from the front end side edge to a position 100 μm farthest from the front end side edge. The Martens hardness at each position decreases from the front end side edge to the position 100 μm away from the front end side edge. The HM1 is 1.0 N / mm 2 Above, and Regarding the scattering curve obtained by causing characteristic X-rays from a Cu tube ball to enter the evaluated surface area of the cleaning blade including the point P1 at an incident angle ω, the index value Kω is determined by the following formula (1): It satisfies Kω1>Kω2>Kω3, where Kω1 represents the index value when ω1=0.5°, Kω2 represents the index value when ω2=1.0°, and Kω3 represents the index value when ω3=3.0°: Kω=[I c / (I c +I a )]×100 (1) Among them I c represents the peak area value at 2θ=21.0° in the scattering curve, and I a represents the peak area value at 2θ=20.2° in the scattering curve, and The erosion rate E of the cleaning blade measured using spherical aluminum oxide particles having an average particle size D50 of 3.0 μm on the evaluated surface area is 0.6 μm / g or less.

2. The cleaning blade according to claim 1, wherein the HM1 is 1.0 to 5.0 N / mm 2 .

3. The cleaning blade according to claim 1, wherein the polyurethane has a structural unit represented by the following chemical formula (1): In the chemical formula (1), R1 and R2 each independently represent a linear divalent hydrocarbon group having 4 to 10 carbon atoms, and "n" represents an integer of 1 or greater. 4 . The cleaning blade according to claim 3 , wherein the polyurethane is a polyurethane having two or more structural units each represented by the chemical formula (1).

5. The cleaning blade according to claim 3 , wherein M2 / M1 is 0.0001 to 0.1000, wherein M1 represents the detected amount of all ions obtained when a sample sampled from the elastic member is heated in an ionization chamber to be vaporized by a mass spectrometer using a direct sample introduction system involving ionizing sample molecules and heated to 1,000° C. at a temperature increase rate of 10° C. / s, and M2 represents the integrated intensity of a peak in a thermogram of ions extracted from a range of m / z values corresponding to the chemical formula (1).

6. A processing cartridge, characterized in that: It includes the cleaning blade according to any one of claims 1 to 5. 7 . A process cartridge according to claim 6 , further comprising a photosensitive member, wherein at least a portion of the elastic member of the cleaning blade abuts against the photosensitive member.

8. An electrophotographic image forming apparatus, characterized in that: It includes the cleaning blade according to any one of claims 1 to 5. 9 . The electrophotographic image forming apparatus according to claim 8 , further comprising an intermediate transfer belt, wherein at least a portion of the elastic member of the cleaning blade abuts against a surface of the intermediate transfer belt.

Images