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

Abstract

To provide a cleaning blade for electrophotography that is excellent in chipping resistance even in long-term use and can stably exhibit excellent cleaning performance.SOLUTION: Polyurethane has a straight chain part represented by -(CH2)m- (m indicates an integer of 4 or more). When the Martens hardness of the position of P1 is defined as HM1, and the Martens hardness of every 30-μm position is measured from a leading end side edge to a position 100 μm separated from the edge, the Martens hardness of each point is gradually reduced from the leading end side edge toward the position 100 μm separated from the edge. HM1 is 1.0 N / mm2 or more. For an index value Kω determined by the following formula (1) from a scattering profile obtained by making a characteristic X-ray from a Cu bulb incident on a cleaning blade including the point P1 at an incident angle of ω, (1) Kω=[Ic / (Ic+Ia)]×100, an erosion rate E measured by using spherical alumina particles having an average particle diameter (D50) of 3.0 μm is 0.6 μm / g or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This disclosure relates to an electrophotographic cleaning blade, a process cartridge, and an electrophotographic image forming apparatus. [Background technology]

[0002] In electrophotographic image forming apparatuses, cleaning blades are provided to remove toner remaining on image carriers such as photoreceptor drums, transfer belts, and intermediate transfer bodies. Many cleaning blades utilize a thermosetting polyurethane elastomer, at least in the portion that contacts the image carrier. This is because thermosetting polyurethane elastomers are plastically deformable and have excellent wear resistance.

[0003] In recent years, the increasing demand for higher image quality in electrophotographic images has led to further reductions in toner particle size. Therefore, cleaning blades used to remove toner remaining on the image carrier require improved cleaning performance to reliably remove even small-particle toner. To address this, it has been proposed to increase the hardness of the contact area of ​​the cleaning blade, thereby increasing the contact pressure with the image carrier. By increasing the hardness of the contact area, the contact width with the image carrier can be narrowed, resulting in increased contact pressure and thus improving the cleaning performance of small-particle toner.

[0004] Patent Document 1 proposes a cleaning blade in which an isocyanate compound is impregnated into urethane rubber from the surface, and the urethane rubber and the isocyanate compound are reacted to maintain flexibility inside the cleaning blade while increasing the hardness of the contact area.

[0005] However, when the cleaning blade according to Patent Document 1 is used over a long period of time, fine chipping may occur at the contact portion. As a result, the contact state with the contacted member (cleaned member) becomes unstable, toner leakage may occur, and streak images may occur.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] One aspect of the present disclosure is directed to providing a cleaning blade for electrophotography that can stably exhibit excellent cleaning performance even when used over a long period of time. Another aspect of the present disclosure is directed to providing a process cartridge and an electrophotographic image forming apparatus having the above cleaning blade.

Means for Solving the Problems

[0008] According to one aspect of the present disclosure, an elastic member containing polyurethane and a support member for supporting the elastic member, and a cleaning blade for electrophotography that cleans the surface of a moving cleaned member by bringing a part of the elastic member into contact with the surface of the cleaned member, the polyurethane has a linear portion represented by -(CH2)m- (where m represents an integer of 4 or more), when the side of the cleaning blade that contacts the surface of the cleaned member is defined as the tip side of the cleaning blade, the elastic member has a plate shape having a main surface facing the cleaned member and a tip surface forming a tip side edge together with the main surface, at least on the tip side. Assume that a first line segment parallel to the tip-side edge and having a distance of 10 μm from the tip-side edge is drawn on the tip surface. When this is done, Let the length of the first line segment be L. Let P1 be a point on the first line segment that is at a distance of 1 / 2L from one end side in the longitudinal direction of the elastic member. Let the Martens hardness of the elastic member measured at the position of P1 be HM1. On a cross section of the elastic member that is orthogonal to the tip surface and the tip-side edge and includes P1, draw a bisector of the angle formed by the main surface and the tip surface. When measuring the Martens hardness at each position every 30 μm from the tip-side edge on the bisector to a position 100 μm away from the tip-side edge, the Martens hardness at each point gradually decreases from the tip-side edge toward the position 100 μm away from the tip-side edge. HM1 is 1.0 N / mm 2 or more, and Regarding the index value Kω obtained from the scattering profile obtained by irradiating characteristic X-rays from a Cu tube target at an incident angle ω on the evaluation surface region of the cleaning blade including the point P1, when the index value at ω1 = 0.5° is Kω1, the index value at ω2 = 1.0° is Kω2, and the index value at ω3 = 3.0° is Kω3, then Kω1 > Kω2 > Kω3. Kω = [I c / (I c + I a )] × 1**00 (1) (I c is the peak area value at 2θ = 21.0° of the scattering profile, and I a is the peak area value at 2θ = 20.2° of the scattering profile. ), and a cleaning blade is provided in which the erosion rate E measured using spherical alumina particles having an average particle diameter (D50) of 3.0 μm in the evaluation surface region is 0.6 μm / g or less.

[0009] Furthermore, according to other aspects of the present disclosure, a process cartridge having the electrophotographic cleaning blade is provided. Furthermore, according to other aspects of the present disclosure, an electrophotographic image forming apparatus having the electrophotographic cleaning blade is provided. [Effects of the Invention]

[0010] This disclosure provides an electrophotographic cleaning blade that exhibits excellent chipping resistance and stable, superior cleaning performance even after long-term use, due to the crystal structure resulting from the orientation of the main chain portion of the polyol's -(CH2)m- (where m is an integer of 4 or more) group.

[0011] Furthermore, according to other aspects of this disclosure, a process cartridge that contributes to the formation of high-quality electrophotographic images can be obtained. Furthermore, according to yet another aspect of this disclosure, an electrophotographic image forming apparatus capable of stably forming high-quality electrophotographic images can be obtained. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic perspective view of an electrophotographic cleaning blade according to one aspect of the present disclosure. [Figure 2] This figure shows the state in which the edge of the cleaning blade is in contact with the object being cleaned when the process cartridge is stationary. [Figure 3] This figure shows a line segment drawn parallel to the tip edge of an elastic member, at a distance of 10 μm from the tip edge. [Figure 4] This figure shows the locations for measuring grazing incidence X-ray diffraction, Martens hardness, and erosion rate. [Figure 5] This diagram shows the location where the Martens hardness is measured. [Figure 6] This diagram shows the method for measuring the erosion rate. [Figure 7] This diagram shows a method for measuring edge chipping. [Modes for carrying out the invention]

[0013] In this disclosure, unless otherwise specified, the expressions "XX or greater and YY or less" or "XX to YY" that represent a numerical range mean a numerical range that includes the lower and upper limits. Furthermore, when a numerical range is described in steps, the upper and lower limits of each numerical range can be combined in any way. Examples of components to be cleaned that can be cleaned with an electrophotographic cleaning blade according to one aspect of this disclosure (hereinafter also simply referred to as the "cleaning blade") include image carriers such as photoreceptors and endless belts such as intermediate transfer belts. Hereinafter, an embodiment of the cleaning blade according to one aspect of this disclosure will be described in detail, using the case where the component to be cleaned is an image carrier as an example. However, this disclosure is not limited to the example where the component to be cleaned is an image carrier.

[0014] <Cleaning blade configuration> Figure 1 is a schematic perspective view of a cleaning blade 1 according to one aspect of the present disclosure. The cleaning blade 1 comprises an elastic member 2 and a support member 3 that supports the elastic member 2. Figure 2 is a schematic example of a cross-sectional view of a cleaning blade according to one aspect of the present disclosure in contact with a member to be cleaned. The elastic member 2 is plate-shaped and has a main surface 4 and a tip surface 5. The main surface 4 is the surface facing the member to be cleaned 6. The tip surface 5 is the surface that, together with the main surface 4, forms the tip side edge when the side that contacts the surface of the member to be cleaned 6 is defined as the tip side. R indicates the rotation direction of the member to be cleaned. A part 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.

[0015] The inventors have found that, for example, a cleaning blade in the embodiment described below exhibits excellent chip resistance and continues to provide superior cleaning performance even after prolonged use. In other words, a cleaning blade according to one aspect of the present disclosure comprises an elastic member containing polyurethane and a support member that supports the elastic member. The polyurethane has a linear portion represented by -(CH2)m- (where m represents an integer of 4 or more). Define the side of the cleaning blade that contacts the surface of the member to be cleaned as the tip side of the cleaning blade. Assume that a first line segment with a distance of 10 μm from the tip side edge is drawn parallel to the tip side edge on the tip surface of the elastic member. Let the length of the first line segment be L. Let P1 be a point on the first line segment at a distance of 1 / 2L from one end side in the longitudinal direction of the elastic member. Let HM1 be the Martens hardness of the elastic member measured at the position of P1. On the cross-section of the elastic member that is orthogonal to the tip surface and the tip side edge including P1, draw the bisector of the angle formed by the main surface and the tip surface. When measuring the Martens hardness at each position every 30 μm from the tip side edge on the bisector to a position 100 μm away from the tip side edge, The Martens hardness at each point gradually decreases from the tip side edge toward the position 100 μm away from the tip side edge. Also, HM1 is 1.0 N / mm 2 or more. Furthermore, regarding the index value Kω obtained from the scattering profile obtained by irradiating characteristic X-rays from a Cu tube target at an incident angle ω to the surface region to be evaluated of the cleaning blade including the point P1, by the following formula (1), When the index value at ω1 = 0.5° is Kω1, the index value at ω2 = 1.0° is Kω2, and the index value at ω3 = 3.0° is Kω3, then Kω1 > Kω2 > Kω3: Kω = [I c / (I c +I a )]×100 (1) (I c is the peak area value at 2θ = 21.0° of the scattering profile, and I a is the peak area value at 2θ = 20.2° of the scattering profile.). Furthermore, the erosion rate E measured using spherical alumina particles with an average particle diameter (D50) of 3.0 μm in the surface region being evaluated is 0.6 μm / g or less.

[0016] The elastic member exhibits a gradual decrease in hardness as it moves away from the surface. This allows for the distribution of stress caused by contact. Furthermore, since there is no interface, such as a boundary between a high-hardness layer and a low-hardness layer, within the elastic member, interlayer delamination does not occur. Moreover, because the interior is less hard than the outermost surface, it conforms better to the surface of the image carrier and exhibits superior cleaning performance compared to cases where the interior is as hard as the outermost surface.

[0017] The Martens hardness of the outermost surface of the elastic member is 1.0 N / mm². 2 More than 5.0N / mm 2 The following is preferable: The surface Martens hardness is 1.0 N / mm². 2 If the above is true, it is possible to contact the photoreceptor drum with a high contact pressure of 5.0 N / mm 2 Under the following conditions, the device can flexibly contact the photoreceptor drum even if it develops streaky irregularities after prolonged use. As a result, the occurrence of cleaning problems can be suppressed.

[0018] The erosion rate E is a value calculated by the micro-slurry jet erosion (MSE) test. The MSE test involves pulse-projecting fine particles of approximately the same diameter as toner onto a cleaning blade, and calculating the erosion rate from the depth of wear on the cleaning blade in the projected area and the amount of particles projected. The erosion rate E indicates the depth of wear per unit projection and is a parameter that indicates the brittleness of the material being evaluated. In other words, the larger the value of the erosion rate E, the more brittle the material being evaluated is. Therefore, cleaning blades with a high erosion rate E are more prone to developing fine chips when used over a long period of time. Generally, polyurethane tends to become more brittle as its hardness increases. However, despite its high hardness, the elastic member according to this disclosure exhibits a small brittleness parameter, as calculated by MSE testing. In other words, it is not brittle despite its high hardness. Furthermore, the MSE test can simulate the accelerated durability performance of a cleaning blade in an electrophotographic device. If the erosion rate E, measured using spherical alumina particles with an average particle size (D50) of 3.0 μm, is 0.6 μm / g or less, the cleaning blade has sufficient strength required. In other words, brittle fracture is unlikely to occur. Therefore, chipping is less likely to occur even during long-term use, and the occurrence of cleaning defects due to chipping can be suppressed. An erosion rate E of 0.5 μm / g or less is even more preferable, as it makes the blade more resistant to wear and suppresses the occurrence of fine chipping. MSE testing can be performed using, for example, an MSE-A type testing apparatus (Parmeso Co., Ltd.).

[0019] Next, the index value Kω is calculated using the grazing incidence X-ray method described below. The grazing incidence X-ray method allows for obtaining information about different depths from the surface by slightly changing the incidence angle of the X-rays, and information about deeper parts can be obtained by increasing the incidence angle. By varying the incidence angle from 0.5° to 3.0°, structural information at depths of 10 μm to 65 μm can be obtained with characteristic X-rays from a Cu tube. Using the structural information obtained at each depth, the index value Kω of crystallinity is calculated from the area ratio of the crystalline peak and the amorphous peak. A larger Kω indicates a higher degree of crystallinity (more crystalline components).

[0020] The elastic member according to this disclosure satisfies the following conditions for the index value Kω obtained by formula (1) above from the scattering profile obtained by incidenting characteristic X-rays from a Cu tube at an incident angle ω onto the surface region to be evaluated. In other words, when the angles of incidence are ω1=0.5°, ω2=1.0°, and ω3=3.0°, the calculated K values ​​are Kω1, Kω2, and Kω3, respectively, and the order is Kω1>Kω2>Kω3. This indicates that the crystallinity is highest at the outermost surface, and gradually decreases towards the interior (from the surface in the depth direction). By having a state where the degree of crystallinity gradually decreases toward the interior, the elastic member achieves a structure in which the surface is moderately hard while maintaining flexibility in the interior.

[0021] The aforementioned physical properties of the elastic member are thought to be due to the polyurethane contained in the elastic member having a crystalline structure determined by the orientation of the main chain portion of a polyol having a linear portion represented by -(CH2)m- (where m is an integer of 4 or more). The polyol used as a raw material preferably has a repeating structural unit shown in the following chemical formula (1), and the obtained polyurethane also preferably has the structure shown in the following chemical formula (1). Polyurethanes having such repeating structural units can crystallize more easily due to intermolecular forces acting between adjacent R1 and R2 portions in the polyol structure. It is preferable that the polyurethane has two or more types of structural units represented by the following chemical formula (1).

[0022] [ka] [In chemical formula (1), R1 and R2 are linear divalent hydrocarbon groups having 4 to 10 carbon atoms. R1 and R2 may be the same or different. n represents an integer of 1 or greater.]

[0023] In the elastic member according to this disclosure, the crystalline structure formed by the orientation of the main chain portion of the polyurethane -(CH2)m- (where m is an integer of 4 or more) polyol is more developed towards the surface. In other words, the degree of crystalline structure development decreases from the surface towards the interior. The harder the part of the material where the crystal structure is more developed, the harder it becomes as the degree of crystal structure development decreases. In the elastic member according to this disclosure, the degree of crystal structure development decreases from the surface to the interior, resulting in a continuous decrease in hardness from the surface to the interior. As a result, the cleaning blade according to this disclosure can achieve both high contact pressure and excellent conformability to the image carrier. Consequently, the cleaning blade according to this disclosure is less prone to cleaning defects. Furthermore, unlike cleaning blades with a multilayer structure consisting of a low-hardness layer and a high-hardness layer, the elastic member according to this disclosure does not have an interface between the low-hardness layer and the high-hardness layer inside, so delamination between layers does not occur even with long-term use.

[0024] Furthermore, in the hardened layer formed by impregnating with an isocyanate compound as disclosed in Reference 1, aggregated hard segments are present. Therefore, when stress is applied to a cleaning blade having this hardened layer, chipping may occur at the tip due to the detachment of the hard segments. On the other hand, in the elastic member according to this disclosure, the polyurethane has a crystalline structure in which the main chains of polyols represented by -(CH2)m- (where m is an integer of 4 or more) are oriented by intermolecular forces, thereby forming a high-hardness region. Therefore, it has excellent shock absorption and is less prone to chipping even when used for a long period of time, due to microscopic stress caused by hardness variations in the toner and photoreceptor drum.

[0025] The structure of chemical formula (1) can be determined using a direct sample introduction type mass spectrometer that ionizes the sample molecule. Specifically, when the sample to be sampled is heated and vaporized in an ionization chamber, and the sample molecules are ionized using a direct sample introduction type mass spectrometer, and the sample is heated to 1000°C at a heating rate of 10°C / s, When M1 is the total amount of ions detected and M2 is the integrated intensity of the peak in the extracted ion thermogram corresponding to the m / z value derived from chemical formula (1), it is preferable that M2 / M1 is between 0.0001 and 0.1000. The inclusion of the structure of chemical formula (1) within this range allows for more reliable formation of the surface crystal structure.

[0026] [Elastic material] The polyurethane (polyurethane elastomer) constituting the elastic member relating to this disclosure is mainly obtained from raw materials such as polyisocyanates, polyols, chain extenders, catalysts, and other additives. These components are described in detail below.

[0027] <Polyisocyanate> Examples of polyisocyanates that can be used include: trimers of 4,4'-diphenylmethane diisocyanate (MDI) as the main component, trimers (isocyanurates) of 1,5-pentamethylene diisocyanate, mixtures of trimers (nurates) and monomers of xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), and xylene diisocyanate. Examples include isocyanates (XDI), 1,5-naphthylene diisocyanate (1,5-NDI), p-phenylenediisocyanate (PPDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI), tetramethylxylene diisocyanate (TMXDI), carbodiimide-modified MDI, polymethylenephenyl polyisocyanate (PAPI), etc. The polyisocyanates described above may be used individually or in combination of two or more types. Alternatively, polyisocyanates may be reacted with various polyols to form prepolymers for use. Among these, a mixture of xylylene diisocyanate trimer (nurate) and xylylene diisocyanate monomer is preferred due to its superior mechanical properties. These may be used individually or in combination of two or more types.

[0028] When hard segments crystallize, their hardness tends to increase, but their brittleness tends to decrease. Therefore, in order to properly maintain the formation of hard segments, the type and amount of isocyanate are appropriately adjusted to achieve a suitable amount of chemical bonding. Among these, trimer isocyanates are particularly preferred because they have a branched structure or a strain structure in their skeleton, which can reduce the formation of hard segments.

[0029] <Polyol> Examples of polyols include polyester polyols, polyether polyols, caprolactone ester polyols, polycarbonate ester polyols, and silicone polyols. Specifically, polyester polyols are a good example. To obtain the effects of this disclosure, it is necessary to gradually decay the crystalline structure from the surface towards the interior. Therefore, as the polyester polyol, a polyester polyol that is solid (crystallized) 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°C to 150°C is preferred.

[0030] [ka] [In chemical formula (1), R1 and R2 are each independently linear divalent hydrocarbon groups having 4 to 10 carbon atoms, and n is an integer greater than or equal to 1.]

[0031] From the viewpoint of manufacturing and crystalline structure characteristics, it is preferable to use two or more polyester polyols with different R1 and R2 values. Furthermore, it may also contain linear divalent hydrocarbon groups having 2 to 3 carbon atoms. The number average molecular weight of the entire polyester polyol is preferably 400 to 10,000, but particularly preferably 800 to 4,000. If it is 800 or higher, the main chain of the polyol crystallizes, resulting in good hardness and chipping resistance of the resulting urethane. If it is 4,000 or lower, the viscosity when heated for use is appropriate, resulting in excellent handling and good hardness, which is particularly preferable.

[0032] When the number of carbon atoms in R1 and R2 in chemical formula (1) is 3 or less, crystallization is difficult to progress, making it difficult to increase the surface hardness. Furthermore, when the number of carbon atoms in R1 and R2 is 11 or more, excessive crystallization occurs, leading to a tendency towards embrittlement. On the other hand, when R1 and R2 are linear divalent hydrocarbon groups having 4 to 10 carbon atoms, the crystalline structure formed by the orientation of the main chain portion of the polyol is highly hard, and the hardness decreases as the crystalline structure disappears. Therefore, when the crystalline structure decays from the surface inward, the hardness can be continuously reduced from the surface inward. As a result, the cleaning blade according to this disclosure can achieve a high contact pressure with the image carrier. It can also improve the ability to conform to the shape of the image carrier.

[0033] The structure represented by chemical formula (1) may be used alone. However, increasing the asymmetry of the crystal structure allows for the formation of a structure with superior impact resistance and a hardened layer with superior chipping resistance. For this reason, it is preferable to combine two or more polyester polyols having linear alkyl chains with 4 to 10 carbon atoms.

[0034] Furthermore, when the first polyester polyol and the second polyester polyol described below are used in combination, the interaction between the crystal structures is promoted, which further improves impact resistance and is therefore preferable. • First polyester polyol: A polyester polyol having a linear alkyl chain with 4 to 6 carbon atoms. • Second type of polyester polyol: A polyester polyol having both linear alkyl chains with 7-10 carbon atoms and linear alkyl chains with 4-6 carbon atoms.

[0035] Suitable polyester polyols for the above purpose include the following: NIPPOLAN® 164 (manufactured by Tosoh Corporation), NIPPOLAN® 4073 (manufactured by Tosoh Corporation), NIPPOLAN® 136 (manufactured by Tosoh Corporation), NIPPOLAN® 4009 (manufactured by Tosoh Corporation), NIPPOLAN® 4010 (manufactured by Tosoh Corporation), NIPPOLAN® 3027 (manufactured by Tosoh Corporation), Polylight® OD-X-2555 (manufactured by DIC Corporation), Polylight® OD-X-2523 (manufactured by DIC Corporation), ETERNACOLL® 3000 series (manufactured by Ube Industries, Ltd.), etc.

[0036] The structure of chemical formula (1) can be determined using a direct sample introduction type mass spectrometer that ionizes the sample molecule. Specifically, when the sample to be sampled is heated and vaporized in an ionization chamber, and the sample molecules are ionized using a direct sample introduction type mass spectrometer, and the sample is heated to 1000°C at a heating rate of 10°C / s, When M1 is the total amount of ions detected and M2 is the integrated intensity of the peak in the extracted ion thermogram corresponding to the m / z value derived from chemical formula (1), it is preferable that M2 / M1 is between 0.0001 and 0.1000. If the structure of chemical formula (1) is included within this range, it is possible to crystallize the surface while suppressing the occurrence of curing defects.

[0037] When polyurethane is produced from polyester polyols and isocyanate compounds, urethane bonds are formed through the reaction between the polyester polyol ends and the isocyanate. As a result, hard segments may be formed via hydrogen bonding of the urethane bonds, which can restrict the movement of the crystallized polyester polyol and prevent it from exhibiting sufficient toughness. Therefore, the polyol component may include a polyrotaxane having a hydroxyl group. Among these, it is preferable that the polyrotaxane contains two or more hydroxyl groups per molecule. In particular, it is preferable to use a polyrotaxane in which a hydroxyl group is introduced at the end of the side chain of the cyclic molecule.

[0038] Polyrotaxanes have a structure in which linear molecules penetrate numerous cyclic molecules, and these cyclic molecules can move freely along the linear molecules. Therefore, they have a structure in which sealing groups are bound to both ends of the linear molecules, preventing the cyclic molecules from detaching from the linear molecules. Since the cyclic molecules have hydroxyl groups, the polyester polyol ends are bonded via isocyanate compounds. As a result, when polyrotaxanes are added, the range in which the crystallized polyester polyol can move during deformation is significantly improved. Thus, fracture during deformation is effectively suppressed, and the toughness improvement effect is promoted.

[0039] Furthermore, when a urethane structure having a linear structure represented by -(CH2)m- (where m is an integer of 4 or more) is formed by the addition of polyrotaxane, an improvement in toughness can be expected due to the crystallization of the linear structure portion. Examples of polyrotaxanes include "Celm® Superpolymer," which is commercially available from Advanced Soft Materials Co., Ltd. In this embodiment, it is preferable to use a polyrotaxane in which a hydroxyl group is introduced at the end of the side chain of the above-mentioned cyclic molecule.

[0040] <Chain extender> For example, glycols can be used as the chain extender. Examples of such glycols include: ethylene glycol (EG), diethylene glycol (DEG), propylene glycol (PG), dipropylene glycol (DPG), 1,4-butanediol (1,4-BD), 1,6-hexanediol (1,6-HD), 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, xylylene glycol (terephthalyl alcohol), triethylene glycol, etc. In addition to the glycols mentioned above, other polyhydric alcohols can also be used, such as trimethylolpropane, glycerin, pentaerythritol, sorbitol, etc. These may be used individually or in combination of two or more types.

[0041] <Catalyst> As the catalyst mentioned above, commonly used catalysts for curing polyurethane elastomers can be used. Examples include tertiary amine catalysts, specifically the following: amino alcohols such as dibutyltin dilaurate, dimethylethanolamine, and N,N,N'-trimethylaminopropylethanolamine; trialkylamines such as triethylamine; tetraalkyldiamines such as N,N,N',N'-tetramethyl-1,3-butanediamine; triethylenediamine, piperazine compounds, triazine compounds, etc. Furthermore, alkali metal organic salts such as potassium acetate and potassium octoate can also be used. In addition, metal catalysts commonly used in urethane formation, such as dibutyltin dilaurate, can also be used. These may be used individually or in combination of two or more types. If necessary, additives such as pigments, plasticizers, waterproofing agents, antioxidants, UV absorbers, and light stabilizers may be added.

[0042] [Support member] The materials constituting the support member of the cleaning blade of this disclosure are not particularly limited and can be made from, for example, metal materials such as steel plates, stainless steel plates, galvanized chromate coated steel plates, and chromium-free steel plates, or resin materials such as 6-nylon and 6,6-nylon. Furthermore, the method of joining the support member 3 and the elastic member 2 is not particularly limited, and a suitable method can be selected from known methods. For example, a method of bonding using an adhesive such as phenolic resin can be used.

[0043] <How to manufacture a cleaning blade> A method for manufacturing a cleaning blade according to this disclosure includes a method for manufacturing an elastic member using the polyol described above and satisfying the following curing conditions.

[0044] [Curing conditions] Typically, the temperature and time of polyurethane curing are controlled to ensure that the urethane reaction proceeds reliably and that it hardens sufficiently. However, in this disclosure, by using the following curing conditions, it is possible to prevent the decrease in brittleness associated with increased hardness, which was a problem with conventional polyurethanes. The curing conditions are described in detail below. In conventional polyurethane manufacturing, the polyurethane is heated and cured until crosslinking is complete, and then aged in a predetermined atmosphere. In contrast, in the manufacturing of the elastic member according to this disclosure, curing is stopped before crosslinking of the polyurethane is complete, and then secondary curing is performed by aging in an atmosphere below the crystallization temperature of the polyol.

[0045] In semi-cured polyurethane obtained by stopping the curing reaction before the crosslinking of polyurethane is complete, unreacted polyol molecules exist with high molecular mobility. While maintaining this state, the semi-cured polyurethane is second-cured in an atmosphere below the crystallization temperature of polyol. This creates a temperature gradient from the surface to the interior of the semi-cured polyurethane. As a result, the surface of the semi-cured polyurethane cools rapidly due to the atmosphere, and the crystallization of the remaining polyol main chain portion progresses. On the other hand, the cooling of the interior of the semi-cured polyurethane due to the atmosphere is slower than that of the surface, so the crosslinking of the polyurethane progresses and the crystallization of polyol becomes less likely to progress. As a result, a structure is formed in which the amount of crystallized polyol gradually decreases from the surface to the interior. The elastic member obtained in this way has high hardness near the surface due to the crystallization of the polyol main chain portion. On the other hand, the interior has low hardness because the crystallization of polyol has not progressed relatively well. Therefore, the Martens hardness gradually decreases from the surface to the interior.

[0046] When polyurethane is cured until crosslinking is complete, as in conventional methods, the crosslinked structure of the polyurethane is well developed, and even if unreacted polyol remains, its molecular mobility is low. Therefore, even if aging is performed below the crystallization temperature of the polyol, the main chain portion of the polyol is unlikely to orient, and surface crystallization is unlikely to progress significantly. Furthermore, if the curing reaction is stopped before the polyurethane crosslinking is complete, and then aging is performed under a temperature atmosphere exceeding the crystallization temperature of the polyol, the crystallization of the polyol main chain will not proceed, and the crosslinking of the polyurethane will proceed on the surface. Therefore, it is difficult to increase the Martens hardness of the surface of the resulting polyurethane.

[0047] In this disclosure, since chemical crosslinking of the urethane is performed during the primary curing, even though it is not yet complete, the surface after secondary curing has a structure in which the crystalline structure of the polyol main chain portion and the chemical crosslinking of the urethane are mixed. If only the crystalline structure of the polyol main chain portion is present on the surface, the Martens hardness of the surface becomes excessively high, and when used for a long period of time, it is not possible to flexibly contact the surface of the photoreceptor drum, which may have streaky irregularities, resulting in cleaning problems.

[0048] The crystallization of polyols can be controlled by the degree of chemical crosslinking of the urethane during primary curing and by the difference between the ambient temperature during secondary curing and the crystallization temperature of the polyol. Reducing the chemical crosslinking of the urethane during primary curing increases the molecular mobility of the polyol after primary curing, making it easier for the surface to crystallize and for crystallization to penetrate deeper into the material. Furthermore, increasing the difference between the ambient temperature during secondary curing and the crystallization temperature of the polyol promotes crystallization, accelerating crystallization both on the surface and in the interior.

[0049] After placing the support member in the mold for the cleaning blade, the polyurethane raw material composition is injected into the mold, and by performing primary and secondary curing as described above, a cleaning blade in which the elastic member and the support member are integrated can be obtained.

[0050] Alternatively, a polyurethane elastomer sheet cured under manufacturing conditions that satisfy the above curing requirements may be molded, cut into strips, and then bonded onto the support member. Bonding methods can be selected from options such as applying or attaching an adhesive to the support member to bond the elastic member, or overlapping the elastic member and the support member and bonding them by heating and pressurizing. Furthermore, after secondary curing, cutting may be performed to adjust the shape of the edge that contacts the image carrier of the cleaning blade. Note that if the polyurethane elastomer sheet is prepared in advance and bonded to the support member, the cutting can be done either before or after bonding.

[0051] <Process cartridges and electrophotographic image forming apparatus> The above-mentioned cleaning blade can be incorporated into a process cartridge that is detachably configured for use with an electrophotographic image forming apparatus. Specifically, for example, the cleaning blade according to this disclosure can be used in a process cartridge comprising an image carrier as a component to be cleaned and a cleaning blade positioned to clean the surface of the image carrier. Such a process cartridge contributes to the stable formation of high-quality electrophotographs.

[0052] Furthermore, an electrophotographic image forming apparatus according to one aspect of the present disclosure comprises an image carrier such as a photoreceptor and a cleaning blade arranged to clean the surface of the image carrier, 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. [Examples]

[0053] The present disclosure will be explained below with reference to manufacturing examples, examples, and comparative examples, but the present disclosure is not limited in any way by these examples. In the examples and comparative examples, raw materials other than those indicated were reagents or industrial chemicals.

[0054] Polyisocyanate components (1) A mixture of xylylene diisocyanate trimer (nurate) and xylylene diisocyanate monomer (molar ratio - trimer:monomer = 1:1.2): Trade name "Takenate (registered trademark) XD-131R", manufactured by Mitsui Chemicals, Inc. (2) A trimer whose main component is 4,4'-diphenylmethane diisocyanate (MDI): Trade name "Millionate (registered trademark) MR-200", manufactured by Tosoh Corporation (3) Trimer of 1,5-pentamethylene diisocyanate (isocyanurate): Trade name "Stabio® D-370N" manufactured by Mitsui Chemicals, Inc. (4) Xylylene diisocyanate: Product name "XDI", manufactured by Tokyo Chemical Industry Co., Ltd. (5) 4,4'-Diphenylmethane diisocyanate: Trade name "MDI", manufactured by Tosoh Corporation

[0055] Polyol components (1) Polyester polyol: Product name "Nipporan (registered trademark) 164" manufactured by Tosoh Corporation The combinations of R1 and R2 in chemical formula (1) are 4 and 6 carbon atoms, respectively. (2) Polyester polyol: Product name "Nipporan (registered trademark) 4009" manufactured by Tosoh Corporation In chemical formula (1), R1 and R2 have 4 carbon atoms. (3) Polyester polyol: Product name "Polylight (registered trademark) OD-X-2555" manufactured by DIC Corporation The combinations of R1 and R2 in chemical formula (1) are 6 and 10 carbon atoms, respectively. (4) Polyrotaxane: Product name "SH1300P-B" manufactured by ASM Co., Ltd.

[0056] Chain extender 1,4-Butanediol (1,4-BD): Manufactured by Tokyo Chemical Industry Co., Ltd. catalyst (1) Dibutyltin dilaurate: Manufactured by Tokyo Chemical Industry Co., Ltd. (2) Tertiary amine catalyst: Trade name "RZETA (registered trademark)" manufactured by Tosoh Corporation

[0057] Examples of urethane polymer preparation [Example 1] The polyol component, chain extender, and urethane catalyst were blended in the masses listed in Table 1. Each component was heated under reduced pressure and dehydrated as needed. The blended mixture was stirred under reduced pressure for 5 minutes to obtain a homogeneous solution mainly composed of polyol. A polyisocyanate component was added to the solution mainly composed of the polyol in the mass shown in Table 1, and after stirring again under reduced pressure for 3 minutes, the mixture was poured into a mold (thickness 2 mm, height 40 mm, width 200 mm) heated to 130°C. After primary curing for 3 minutes, the mold was rapidly cooled to 25°C and held in the mold for 12 hours for secondary curing. After that, the mold was demolded to obtain an integral molded body 1 of polyurethane and support member.

[0058] The mold used was coated with a release agent before the polyurethane elastomer composition was injected. The release agent was a mixture of the following materials. ELEMENT14 PDMS 1000-JC (product name, manufactured by Momentive Performance Materials) 5.06g ELEMENT14 PDMS 10K-JC (product name, manufactured by Momentive Performance Materials) 6.19g SR1000 (product name, manufactured by Momentive Performance Materials) 3.75g EXXSOL® DSP145 / 160 (product name, manufactured by ExxonMobil) 85g This integrally molded body was cut as needed to obtain cleaning blades 1. The edge angle was 90 degrees, and the distances in the short, thickness, and longitudinal directions of the polyurethane were set to 7.5 mm, 1.8 mm, and 240 mm, respectively. The obtained cleaning blades 1 were evaluated by the following method.

[0059] [Method for measuring polyol components] The polyol components were measured using the direct sample introduction method (DI method), in which the sample was directly introduced into the ion source without passing it through a gas chromatograph (GC). The apparatus used was a POLARIS Q manufactured by Thermo Fisher Scientific K.K., employing a Direct Exposure Probe (DEP). Assuming that a first line segment is drawn on the tip surface parallel to the tip edge, at a distance of 10 μm from the tip edge, let the length of this first line segment be L, polyurethane was scraped off with a bio-cutter from a point P1 located 1 / 2L from one end of the first line segment.

[0060] Approximately 0.1 μg of the sample collected at P1 was fixed to a filament located at the tip of the probe and directly inserted into the ionization chamber. Subsequently, it was rapidly heated from room temperature to 1000°C at a constant heating rate (10°C / s), and the vaporized gas was detected by a mass spectrometer. The detection amount M1 for all ions was defined as the sum of the integrated intensities of all peaks in the obtained total ion current thermogram. The detection amount M2 for the polyol component was defined as the integrated intensity within the range of m / z values ​​calculated using formula (2). m / z value range {200 + [14 × (x - 4) + 14 × (y - 4)] + 1} ± 0.5 Equation (2) (x and y are the number of carbon atoms in R1 and R2, respectively, in chemical formula (1)) The arithmetic mean values ​​obtained from samples scraped from five points starting from point P1 were used as the M2 / M1 values ​​in this disclosure.

[0061] [Analysis of crystallinity] The degree of crystallinity was measured by grazing incidence X-ray diffraction (XRD) using an X-ray diffractometer (product name: ATX-G; manufactured by Rigaku Corporation). The X-ray incidence angles were set to ω1 = 0.5°, ω2 = 1.0°, and ω3 = 3.0°, and the crystal peak areas measured at each angle were respectively I c1 , I c2 , I c3 Let the amorphous peak area be I a1 , I a2 , I a3 This indicates that a smaller X-ray incidence angle represents the condition of the surface.

[0062] The measurement conditions are as follows: Tube: Cu (40kV20mA) Slitting conditions: S2 (1mm vertical, 0.1mm horizontal) RS, GS: open, Soller slit=0.41

[0063] For peak area analysis, we used Origin 2016 (developed by Origin Lab Corporation, USA). First, the background was determined and subtracted from the XRD pattern. Next, the peak was separated into a crystalline peak at 2θ=21° and a peak due to the amorphous component at 2θ=20°. The position of the crystalline peak was fixed, and numerical fitting was performed by numerically constraining the integral value of each component to be a positive value and the peak's FWHM to be an appropriate value. The area value Ic of the crystalline peak was taken as the area value obtained by integrating from the baseline in the region 2θ=13°~30°, when the baseline was drawn from 2θ=3°~40°, for the peak with the peak top at 2θ=21°. The area value Ia of the amorphous peak was taken as the area value obtained by integrating from the baseline in the region 2θ=13°~30°, when the baseline was drawn from 2θ=3°~40°, for the peak with the peak top at 2θ=20.2°. c1 , I a1 Substituting this into equation (1) below, we obtained the index Kω1 of crystallinity. Similarly, I c2 , I a2 Substitute the following equation (1) to obtain the index Kω2, I c3 , I a3 Substituting this into equation (1) below, we obtained the index Kω3. Kω=[I c / ( I c +I a )] × 100 (1) The obtained values ​​of Kω1, Kω2, and Kω3 were evaluated to see if they satisfied the following relationship. Then, in the "Crystallization Analysis" column of Tables 2A and 2B, "Y" was written if the relationship was satisfied, and "N" if it was not. Crystallinity: If Y satisfies Kω1 > Kω2 > Kω3 If N:Kω1>Kω2>Kω3 is not satisfied

[0064] If Kω1, Kω2, and Kω3 satisfy the relationship Kω1>Kω2>Kω3, it indicates that the proportion of crystal peaks at 2θ=21° decreases from the surface towards the interior. In other words, it indicates that the degree of crystallinity decreases as you move from the surface of the cleaning blade towards the interior. As shown in Figures 3 and 4, the measurement point was defined as point P1, which is 1 / 2L from one end of the first line segment, assuming that a first line segment is drawn parallel to the tip edge on the tip surface 5, with a distance of 10 μm from the tip edge. The length of this first line segment is denoted as L.

[0065] [Martens hardness] Martens hardness was measured using the Shimadzu Dynamic Microhardness Tester "DUH-W211S" manufactured by Shimadzu Corporation. The measurement environment was 23°C and 55% relative humidity. A triangular pyramidal diamond indenter with a 115° ridge spacing was used, and the Martens hardness was calculated using the following formula (3). Martens hardness: HM = α × P / D 2 Formula (3)

[0066] In equation (3), α is a constant determined by the indenter shape, P is the test force (mN), and D is the amount the indenter penetrates the sample (indentation depth) (μm). The measurement conditions are as follows. α:3.8584 D: 2.0 μm Load speed: 0.03mN / sec Hold time: 5 seconds

[0067] Measurement point: Assuming that a first line segment is drawn parallel to the tip edge, with a distance of 10 μm from the tip edge, as shown in Figure 3, As shown in Figure 4, the length of the first line segment was defined as L, and point P1 was defined as a point 1 / 2L from one end of the first line segment. The Martens hardness HM1 was measured at position P1. Furthermore, as shown in Figure 5, the angle θ between the main surface 4 and the tip surface is in the cross section of the elastic member that is perpendicular to the tip surface 5 including P1 and the tip side edge. 4-5 A bisector was drawn. Then, the Martens hardness HM2, HM3, and HM4 were measured at positions (P2, P3, and P4) 30 μm, 60 μm, and 90 μm from the tip edge on the bisector.

[0068] [Erosion rate E] The erosion rate was measured using the "MSE-A type test apparatus" manufactured by Parmeso Co., Ltd. Spherical alumina powder with an average particle size of 3.0 μm (product name "AX3-15," manufactured by Nippon Steel & Sumitomo Metal Materials Corporation, Micro Company) was dispersed in water to prepare a slurry containing 3% by mass of spherical alumina relative to the total mass of the slurry.

[0069] As shown in Figure 6, the cleaning blade was fixed to a stand (not shown) so that the slurry 62 projected from the projection nozzle 61 was projected 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 projection nozzle 61 was set to 4 mm, and the slurry 62, in which spherical alumina 64 was dispersed in water 65, was projected. The measurement environment was set to a temperature of 23°C and a relative humidity of 55%, with a slurry projection speed of 100 m / sec. The cutting depth was measured using a stylus-type surface shape measuring instrument manufactured by Kosaka Laboratory Co., Ltd., with a diamond stylus having a tip radius of R10 μm. The projection conditions were adjusted using the following method. Prior to the measurement, the slurry projection conditions were adjusted in the aforementioned measurement environment using an existing hardness reference sample (product name "HRC-45", manufactured by Yamamoto Scientific Instruments Research Institute Co., Ltd.) so that 6.0 μm of slurry was removed when 6.0 g of slurry was projected. The erosion rate E in this case was 1.0 μm / g.

[0070] Assuming that a first line segment is drawn parallel to the tip edge, with a distance of 10 μm from the tip edge, as shown in Figure 3, the length of the first line segment is denoted as L, and a point on the first line segment at a distance of 1 / 2 L from one end is defined as P1. At P1, slurry is projected until the cutting depth reaches 20 μm, and the erosion rate E is calculated from the amount of slurry used using the following formula (3). Erosion rate E (μm / g) = Cutting depth 20 μm / Projection amount of spherical alumina particles (g) (3)

[0071] [Evaluation of cleaning performance] Cleaning blade 1 was incorporated into the process cartridge of a color laser beam printer (product name: HP LaserJet Enterprise Color M553dn, manufactured by Hewlett-Packard) as a cleaning blade for the photosensitive drum, which is the component to be cleaned. Next, 10,000 images were formed under normal temperature conditions (temperature 23°C, relative humidity 55%) and then evaluated (hereinafter referred to as "normal evaluation"). Furthermore, the developing machine used was replaced with a new one containing a completely replaced toner cartridge, and the image processing was repeated for 10,000 images before evaluation (hereinafter referred to as "double evaluation").

[0072] Furthermore, waste toner was periodically extracted by puncturing the back of the cartridge during the evaluation. The performance of the obtained images was ranked according to the following evaluation criteria. Then, in the "Cleaning Performance Evaluation Rank" column of Tables 2A and 2B, "A," "B," "C," "D," or "E" were written according to the evaluation result. Rank A: Image defects (streaks on the image) caused by the cleaning blade do not occur in either the normal or double-checked evaluation. Rank B: Image defects (streaks on the image) caused by the cleaning blade do not occur in normal evaluation, but occur very slightly in double evaluation (streaks with a length of 5 mm or less on the image occur). Rank C: Image defects (streaks on the image) caused by the cleaning blade do not occur in normal evaluation, but occur slightly in double evaluation (streaks exceeding 5mm in length but not exceeding 10mm on the image). Rank D: Image defects caused by the cleaning blade (streaks on the image) do not occur in normal evaluation, but do occur in double evaluation (streaks with a length exceeding 10 mm appear on the image). Rank E: Image defects (streaks on the image) caused by the cleaning blade occur in both normal and double-checked settings.

[0073] [Evaluation of edge chipping in cleaning blades] After the above cleaning performance evaluation (2x evaluation) was completed, the cleaning blade was removed from the cartridge and observed under 1000x magnification using a digital microscope (product name: main unit VHX-5000, lens VH-ZST, manufactured by Keyence Corporation). As shown in Figure 7, the cleaning blade was placed below the digital microscope 7 with the support member 3 tilted at a 45° angle to the horizontal, so that the support member 3 was above and the tip surface 5 of the elastic member was below. The entire longitudinal area (length L) of the tip (the part closest to the tip surface 5) of the main surface 4 of the elastic member of the cleaning blade was then observed.

[0074] As shown in the enlarged section of Figure 7, the maximum distance in the short-side direction of the chipped edge (distance from the imaginary line representing the main surface assuming no chipping occurred) was measured as the "edge chipping amount" and evaluated according to the following criteria. Then, in the "Edge Chip Evaluation Rank" column of Tables 2A and 2B, "A" was entered according to the evaluation result. + ”, “A”, “B”, “C”, “C ― It was written as "" or "D". Rank A + The edge chipping amount is less than 0.1 μm. Rank A: Edge chipping is between 0.1 μm and less than 0.5 μm. Rank B: Edge chipping is between 0.5 μm and less than 1.0 μm. Rank C: Edge chipping is between 1.0 μm and less than 3.0 μm. Rank C ― The edge chipping amount is 3.0 μm or more and less than 3.5 μm. Rank D: Edge chipping is 3.5 μm or larger.

[0075] [Examples 2-12] Cleaning blades 2 to 12 were obtained in the same manner as in Example 1, except that the formulation 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 Tables 2A and 2B.

[0076] [Comparative Examples 1-2] Cleaning blades 13-14 were obtained in the same manner as in Example 1, except that the formulation 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. [Comparative Example 3] The impregnation agent was prepared by mixing the following materials. Polymeric MDI (Product name: MR-100, manufactured by Nippon Polyurethane) 10g Silicone resin (product name: Modiper FS-700, manufactured by NOF Corporation) 2g 2. Butanone (manufactured by Tokyo Chemical Industry Co., Ltd.) 88g The 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 in an environment of 23°C / 55% relative humidity to obtain the cleaning blade 15. The same evaluation as in Example 1 was performed, and the evaluation results are shown in Table 2B.

[0077] [Table 1]

[0078] [Table 2A]

[0079] [Table 2B]

[0080] This disclosure is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of this disclosure.

[0081] This disclosure includes the following components. [Configuration 1] An electrophotographic cleaning blade comprising an elastic member containing polyurethane and a support member for supporting the elastic member, wherein a part of the elastic member is brought into contact with the surface of a moving member to be cleaned to clean the surface of the member to be cleaned, The polyurethane has a linear portion represented by -(CH2)m- (where m is an integer of 4 or more), When the side of the cleaning blade that contacts the surface of the member to be cleaned is defined as the tip side of the cleaning blade, The elastic member has a plate shape, at least at the tip end, having a main surface that faces the member to be cleaned and a tip surface that together with the main surface forms the tip edge. Assuming that a first line segment is drawn on the tip surface parallel to the tip edge, with a distance of 10 μm from the tip edge, Let the length of the first line segment be L. Let P1 be a point on the first line segment that is at a distance of 1 / 2L from one end of the elastic member in the longitudinal direction. Let HM1 be the Martens hardness of the elastic member measured at position P1. When the Martens hardness is measured at every 30 μm intervals between the tip surface and the tip edge, in a cross section of the elastic member perpendicular to the tip surface and the tip edge including P1, a bisector of the angle between the main surface and the tip surface is drawn, and the angle between the tip edge and a position 100 μm away from the tip edge is measured, The Martens hardness at each point gradually decreases from the tip edge toward a position 100 μm away from the tip edge. The HM1 is 1.0 N / mm 2 That is all, and, For the index value Kω obtained from the scattering profile obtained by incidenting characteristic X-rays from a Cu tube at an incident angle ω onto the surface region of the cleaning blade to be evaluated, including point P1, using the following formula (1): When ω1 = 0.5°, the index value is Kω1; when ω2 = 1.0°, the index value is Kω2; and when ω3 = 3.0°, the index value is Kω3. Then Kω1 > Kω2 > Kω3. Kω=[I c / ( I c +I a )] × 100 (1) (I c I is the peak area value of the scattering profile at 2θ = 21.0°. aThis is the peak area value of the scattering profile at 2θ = 20.2°. ), and, A cleaning blade characterized in that the erosion rate E measured using spherical alumina particles with an average particle diameter (D50) of 3.0 μm in the surface region to be evaluated is 0.6 μm / g or less.

[0082] [Configuration 2] The aforementioned HM1 is 1.0 N / mm 2 More than 5.0N / mm 2 The cleaning blade described in Configuration 1 below. [Configuration 3] The cleaning blade according to configuration 1 or 2, wherein the polyurethane has a structural unit represented by the following chemical formula (1). [ka] [In chemical formula (1), R1 and R2 are each independently linear divalent hydrocarbon groups having 4 to 10 carbon atoms, and n is an integer greater than or equal to 1.] [Structure 4] The cleaning blade according to configuration 3, wherein the polyurethane is a polyurethane having two or more structural units represented by the chemical formula (1). [Composition 5] A cleaning blade according to configuration 3 or 4, wherein when a sample sampled from the elastic member is heated and vaporized in an ionization chamber and the sample molecules are ionized using a direct sample introduction type mass spectrometer, and the sample is heated to 1000°C at a heating rate of 10°C / second, the total amount of ions detected is M1, and the integrated intensity of the peaks of the extracted ion thermogram corresponding to the range of m / z values ​​derived from the chemical formula (1) is M2, and M2 / M1 is 0.0001 to 0.10000.

[0083] [Composition 6] A process cartridge characterized by having a cleaning blade as described in any of configurations 1 to 5. [Composition 7] The process cartridge according to configuration 6, wherein the process cartridge further comprises a photoreceptor, and at least a portion of the elastic member of the electrophotographic cleaning blade is in contact with the photoreceptor. [Structure 8] An electrophotographic image forming apparatus characterized by having a cleaning blade as described in any of configurations 1 to 5. [Composition 9] The electrophotographic image forming apparatus according to configuration 8, further comprising an intermediate transfer belt, wherein at least a portion of the elastic member of the electrophotographic cleaning blade is in contact with the surface of the intermediate transfer belt. [Explanation of Symbols]

[0084] 1: Cleaning blade, 2: Elastic member, 3: Support member, 4: Main surface facing the member to be cleaned, 5: Tip surface that forms the tip edge together with the main surface, 6: Member to be cleaned, 7: Digital microscope, R: Rotational direction of the member to be cleaned

Claims

1. An electrophotographic cleaning blade comprising an elastic member containing polyurethane and a support member for supporting the elastic member, wherein a part of the elastic member is brought into contact with the surface of a moving member to be cleaned to clean the surface of the member to be cleaned, The polyurethane is -(CH ２ It has a linear portion represented by m - (where m is an integer greater than or equal to 4), When the side of the cleaning blade that contacts the surface of the member to be cleaned is defined as the tip side of the cleaning blade, The elastic member has a plate shape, at least at the tip end, having a main surface that faces the member to be cleaned and a tip surface that together with the main surface forms the tip edge. Assuming that a first line segment is drawn on the tip surface parallel to the tip edge, with a distance of 10 μm from the tip edge, Let the length of the first line segment be L. Let P1 be a point on the first line segment that is at a distance of 1 / 2L from one end of the elastic member in the longitudinal direction. Let HM1 be the Martens hardness of the elastic member measured at position P1. When the Martens hardness is measured at each position every 30 μm between the tip surface and the tip edge, in a cross section of the elastic member perpendicular to the tip surface and the tip edge including P1, a bisector of the angle between the main surface and the tip surface is drawn, and the angle between the tip edge and a position 100 μm away from the tip edge is measured, The Martens hardness at each point gradually decreases from the tip edge toward a position 100 μm away from the tip edge. The HM1 is 1.0 N / mm ２ That is all, and, The index value Kω obtained from the scattering profile obtained by incidenting characteristic X-rays from a Cu tube at an incident angle ω onto the surface region of the cleaning blade to be evaluated, including point P1, is as follows: ω１ Let the index value when θ = 0.5° be K ω１ , ω２ let the index value when θ = 1.0° be K ω２ , ω３ let the index value when θ = 3.0° be K ω３ When this is the case, K ω１ > K ω２ > K ω３ and K ω =[I ｃ / (I ｃ +I ａ )]×100 (1) (I ｃ I is the peak area value of the scattering profile at 2θ = 21.0°. ａ This is the peak area value of the scattering profile at 2θ = 20.2°, and, In the surface region being evaluated, the average particle diameter (D ５０ A cleaning blade characterized in that its erosion rate E, measured using 3.0 μm spherical alumina particles, is 0.6 μm / g or less.

2. The aforementioned HM1 is 1.0 N / mm ２ Above, 5.0N / mm ２ The cleaning blade according to claim 1, which is as follows:

3. The cleaning blade according to claim 1, wherein the polyurethane has a structural unit represented by the following chemical formula (1). 【Chemistry 1】 [In chemical formula (1), R １ , R ２ Each of these is an independent linear divalent hydrocarbon group having 4 to 10 carbon atoms, and n is an integer greater than or equal to 1.

4. The cleaning blade according to claim 3, wherein in the chemical formula (1), R1 is a linear divalent hydrocarbon group having 4 carbon atoms, and R2 is a linear divalent hydrocarbon group having 6 carbon atoms.

5. The cleaning blade according to claim 3, wherein the polyurethane is a polyurethane having two or more structural units represented by the chemical formula (1).

6. The cleaning blade according to claim 3, wherein when a sample sampled from the elastic member is heated and vaporized in an ionization chamber and the sample molecules are ionized using a direct sample introduction type mass spectrometer, and the sample is heated to 1000°C at a heating rate of 10°C / second, the total amount of ions detected is M1, and the integrated intensity of the peaks of the extracted ion thermogram corresponding to the range of m / z values ​​derived from the chemical formula (1) is M2, and M2 / M1 is 0.0001 to 0.10000.

7. A process cartridge characterized by having a cleaning blade as described in any one of claims 1 to 6.

8. The process cartridge according to claim 7, wherein the process cartridge further comprises a photoreceptor, and at least a portion of the elastic member of the cleaning blade is in contact with the photoreceptor.

9. An electrophotographic image forming apparatus characterized by having a cleaning blade according to any one of claims 1 to 6.

10. The electrophotographic image forming apparatus according to claim 9, further comprising an intermediate transfer belt, wherein at least a portion of the elastic member of the cleaning blade is in contact with the surface of the intermediate transfer belt.

Images