Cleaning blade and method for manufacturing elastic member of cleaning blade

Abstract

The cleaning blade includes an elastic member having an edge in contact with the photoreceptor member. The elastic member has a surface layer formed from a polyurethane rubber containing an isocyanate silane, and a rubber part formed from a polyurethane rubber not containing an isocyanate silane. The surface layer includes at least an edge. The value obtained by subtracting the press-in elastic modulus of the rubber part from the press-in elastic modulus of the surface of the surface layer is-0.01 MPa or less.

Description

Technical Field

[0001] The present invention relates to a cleaning blade used in an image forming apparatus using an electrophotographic method and a method for manufacturing an elastic member of the cleaning blade. Background Art

[0002] In an image forming apparatus using an electrophotographic method (e.g., a copying machine, a printer), a toner image formed on the surface of a photoreceptor member is transferred onto a moving sheet. The toner remaining on the surface of the photoreceptor member is removed by a cleaning blade.

[0003] The cleaning blade has appropriate elasticity to cause moderate deformation, and preferably has appropriate abrasion resistance to ensure a long life. Generally, from the viewpoints of elasticity and abrasion resistance, at least the front end portion of the cleaning blade that contacts the surface of the photoreceptor member is made of thermosetting polyurethane rubber (urethane elastomer).

[0004] Patent Documents 1 and 2 disclose a surface treatment layer having a low coefficient of friction and a high elastic modulus (i.e., high hardness) formed on an elastic member of a cleaning blade.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent No. 6094780 Gazette

[0008] Patent Document 2: Japanese Patent No. 6460358 Gazette Summary of the Invention

[0009] In an image forming apparatus, most of the photoreceptor member and the components around it are provided as a unit. In this case, the life of the unit is determined by the component with the shortest life. The cleaning blade is a component with a short life, and thus it is desired to further extend its life.

[0010] The present invention provides a cleaning blade with high abrasion resistance and a long life, and a method for manufacturing an elastic member of the cleaning blade.

[0011] One aspect of the present invention provides a cleaning blade. The cleaning blade includes an elastic member having an edge that contacts a photoreceptor member. The elastic member has a surface layer formed of a polyurethane rubber containing isocyanate silane and a rubber portion formed of a polyurethane rubber not containing isocyanate silane. The surface layer includes at least the edge. The value obtained by subtracting the indentation elastic modulus of the rubber portion from the indentation elastic modulus of the surface of the surface layer is -0.01 MPa or less.

[0012] Another aspect of the present invention provides a method for manufacturing an elastic member of a cleaning blade. The method for manufacturing an elastic member of a cleaning blade includes forming a surface treatment layer containing isocyanate silane on a raw material made of polyurethane rubber. Forming the surface treatment layer includes: impregnating a treatment liquid containing isocyanate silane into at least a region including a portion corresponding to an edge in contact with a photoreceptor member of the raw material; and drying the treatment liquid to form the surface treatment layer such that a value obtained by subtracting an indentation modulus of elasticity of the surface of the raw material before forming the surface treatment layer from an indentation modulus of elasticity of the surface of the surface treatment layer is -0.01 MPa or less.

[0013] In the aspect of the present invention, it is possible to improve the wear resistance of the front end portion of the elastic member of the cleaning blade and extend the life of the elastic member of the cleaning blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 FIG. is a view showing a cleaning blade in use according to an embodiment of the present invention.

[0015] Figure 2 FIG. is an enlarged view of the elastic member of the cleaning blade when not in use.

[0016] Figure 3 FIG. is a cross-sectional view of an elastic member according to an example of an embodiment of the present invention.

[0017] Figure 4 FIG. is a cross-sectional view of an elastic member according to another example of an embodiment of the present invention.

[0018] Figure 5A FIG. is a table showing the characteristics and test results of samples made to investigate the preferred range of the present invention.

[0019] Figure 5B FIG. is a table showing the characteristics and test results of samples made to investigate the preferred range of the present invention.

[0020] Figure 6 FIG. is a view showing the situation of a wear test of a cleaning blade for investigating the preferred range of the present invention.

[0021] Figure 7 FIG. shows a state diagram of wear measurement of a cleaning blade. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings. The scale of the drawings is not necessarily accurate, and sometimes a part of the features may be exaggerated or omitted.

[0023] As Figure 1As shown, the cleaning blade 10 of the embodiment is disposed near the photosensitive drum (photosensitive member) 1 of an image forming apparatus using an electrophotographic method. As is well known, a transfer device 2 is disposed near the photosensitive drum 1. During the period when a sheet S of paper conveyed by a conveyance device (not shown) passes through the nip between the photosensitive drum 1 and the transfer device 2, the toner image formed on the photosensitive drum 1 is transferred to the sheet S.

[0024] The toner remaining on the surface of the photosensitive drum 1 without being transferred to the sheet S is removed by the cleaning blade 10. The image forming apparatus has many other components as is well known to those skilled in the art, but descriptions of other components are omitted.

[0025] The cleaning blade 10 has a hard plastic or metal bracket (support member) 11 and an elastic member 12 fixed to the bracket 11. Both the bracket 11 and the elastic member 12 extend parallel to the axial direction of the photosensitive drum 1. The bracket 11 is fixed to a fixed position of the image forming apparatus and supports the elastic member 12. The bracket 11 has high rigidity, and the elastic member 12 has appropriate elasticity. The edge 14 of the front end portion 13 of the elastic member 12 contacts the outer peripheral surface of the photosensitive drum 1. The edge 14 of the front end portion 13 in contact with the photosensitive drum 1 scrapes off the residual toner on the photosensitive drum 1. The elastic member 12, particularly the front end portion 13, is elastically deformed by the reaction force received from the photosensitive drum 1.

[0026] It is preferable to improve the wear resistance of the front end portion 13 of the cleaning blade 10 and extend the life of the cleaning blade 10. The front end portion 13 is worn due to friction with the photosensitive drum 1. It is considered that the wear of the front end portion 13 is caused by the repeated elongation of the edge 14 of the front end portion 13 and the cutting off of the elongated portion. In order to suppress the wear resistance of the front end portion 13, it is preferable that at least the front end portion 13 of the cleaning blade 10, particularly the edge 14, has appropriate mechanical strength and a low coefficient of friction.

[0027] Figure 2 It is an enlarged view of the cleaning blade when not in use, showing the angle α of the edge 14 of the front end portion 13. The angle α is usually 90 to 105 degrees. In Figure 2 the photosensitive drum 1 is represented by a dashed line.

[0028] Figure 3 and Figure 4The cross-section of an example of the elastic member 12 showing an embodiment of the present invention is presented. The elastic member 12 of the embodiment is formed of thermosetting polyurethane rubber. More precisely, the elastic member 12 has a surface treatment layer (surface layer) 12s formed of thermosetting polyurethane rubber containing isocyanate silane and an untreated portion (rubber portion) 12n formed of thermosetting polyurethane rubber not containing isocyanate silane. The surface treatment layer 12s is formed by impregnating a treatment liquid containing isocyanate silane into the raw material of the thermosetting polyurethane rubber and drying the treatment liquid. The untreated portion 12n is an area where the treatment liquid is not impregnated and remains in the state of the raw material of the thermosetting polyurethane rubber.

[0029] The main purpose of forming the surface treatment layer 12s is to reduce the coefficient of friction of the elastic member 12, particularly at the edge 14 and its vicinity.

[0030] In Figure 3 and Figure 4 the dimensions of the elastic member 12 are described. The elastic member 12 is a rectangular plate and has, for example, a thickness of 2 mm and a length of 14 mm. Although not shown, the elastic member 12 has, for example, a width of 350 mm (the length in the direction perpendicular to the plane of the figure). However, these dimensions of the elastic member 12 are merely illustrative for reference and are not intended to limit the present invention. As Figure 3 and Figure 4 shown, the thickness t of the surface treatment layer 12s is, for example, 10 μm to 200 μm, which is less than the thickness of the elastic member 12.

[0031] In Figure 3 the example, the surface treatment layer 12s is formed on all surfaces of the elastic member 12. This is because the surface treatment layer 12s is formed by impregnating the treatment liquid into the entire surface of the elastic member 12 (for example, dipping the elastic member 12 in the treatment liquid). The thickness t of the surface treatment layer 12s is 10 μm to 200 μm, which is less than the thickness of the elastic member 12.

[0032] In Figure 4 the example, the surface treatment layer 12s is formed at the edge 14 and its vicinity of the front end portion 13 of the elastic member 12. This is because the surface treatment layer 12s is formed by impregnating the treatment liquid into the area including the portion corresponding to the edge 14 of the elastic member 12. Therefore, in the present invention, the surface treatment layer 12s does not need to be formed on all surfaces of the elastic member 12 but is formed in at least the area including the edge 14. In Figure 4 the example, the area where the surface treatment layer 12s is formed has a range of 2 mm in the length direction of the elastic member 12 and a range of 0.5 mm in the thickness direction of the elastic member 12 starting from the edge 14, but the dimensions of this area are merely illustrative and are not intended to limit the present invention.

[0033] In Figure 4 the example of Figure 4 , the non-treated portion 12n is exposed on the surface of the elastic member 12. By recording the area penetrated by the treatment liquid, the non-treated portion 12n can be distinguished from the surface treatment layer 12s. Therefore, in Figure 4 the example of Figure 4 , it is easy to measure the indentation elastic modulus (described later) of the surface of the non-treated portion 12n, and it is easy to measure the dynamic friction coefficient of the surface of the non-treated portion 12n. The indentation elastic modulus of the surface of the non-treated portion (rubber portion) 12n is equal to the indentation elastic modulus of the surface of the raw material of the elastic member 12 before surface treatment of the surface treatment layer (surface layer) 12s. The dynamic friction coefficient of the surface of the non-treated portion 12n is equal to the dynamic friction coefficient of the surface of the raw material of the elastic member 12 before surface treatment of the surface treatment layer 12s.

[0034] In Figure 3 the example of Figure 3 , the non-treated portion 12n is not exposed on the surface of the elastic member 12. However, by cutting the elastic member 12 and measuring the hardness of a plurality of local portions of the elastic member 12, the non-treated portion 12n can be distinguished from the surface treatment layer 12s. This is because the elastic modulus (in other words, hardness) of the surface treatment layer 12s containing isocyanate silane is different from the elastic modulus of the non-treated portion 12n not containing isocyanate silane. Therefore, in Figure 3 the example of Figure 3 , it is also easy to measure the indentation elastic modulus (described later) of the surface of the non-treated portion 12n. In addition, if the surface roughness of the non-treated portion 12n obtained by cutting the elastic member 12 is the same as the surface roughness of the surface treatment layer 12s (or if the surface of the non-treated portion 12n is processed in the same manner), the dynamic friction coefficient of the surface of the non-treated portion 12n can be measured under the same conditions as the surface of the surface treatment layer 12s.

[0035] The applicant prepared a plurality of samples of the elastic member 12, measured the characteristics of these samples, and conducted a wear test.

[0036] The samples were manufactured according to the following steps.

[0037] First, three types of thermosetting polyurethane rubbers as raw materials of the elastic member 12 were prepared.

[0038] As Figure 5A and Figure 5B shown, the hardnesses of the three polyurethane rubbers are 76, 88, and 63, respectively. The rubber hardness was measured by applying a load of 9.8 N to each test piece in an environment of 23°C and 55% relative humidity using a Type A Durometer manufactured by Teclock Corporation (Nagano, Japan) based on JIS K6301. The thickness of the test piece was 12 mm.

[0039] The polyurethane rubber with a hardness of 76 is manufactured from a mixture containing "POLYLITE CT-4117" (trade name) manufactured by DIC Corporation (Tokyo, Japan) as the polyol, 4,4'-diphenylmethane diisocyanate (MDI) as the isocyanate, and trimethylolethane (TME) as the crosslinking agent. The molecular weight of "POLYLITE CT-4117" is 2000.

[0040] The polyurethane rubber with a hardness of 88 is manufactured from a mixture containing "POLYLITE CT-4117" as the polyol, 4,4'-diphenylmethane diisocyanate (MDI) as the isocyanate, and triethylpropane as the crosslinking agent.

[0041] The polyurethane rubber with a hardness of 63 is manufactured from a mixture containing "Kuraray Polyol O-2010" (trade name) manufactured by Kuraray Co., Ltd. (Tokyo, Japan) as the polyol, 4,4'-diphenylmethane diisocyanate (MDI) as the isocyanate, and triethylpropane as the crosslinking agent. The molecular weight of "Kuraray Polyol O-2010" is 2000.

[0042] Elastic members 12 equivalent to the samples shown in Figure 5A and Figure 5B are cut out from these rubbers.

[0043] Next, the treatment liquid is permeated into the surface of the elastic member 12 and the treatment liquid is dried, thereby forming a surface treatment layer 12s. Specifically, the treatment liquid is dip-coated on the surface of the elastic member 12. In the obtained samples, as shown in Figure 3 , the surface treatment layer 12s is formed on the entire surface of the elastic member 12. However, the method of permeating the treatment liquid into the elastic member 12 may also be spraying the treatment liquid on the surface of the elastic member 12. In addition, as shown in Figure 4 , the surface treatment layer 12s may also be formed only at the edge 14 of the front end portion 13 of the elastic member 12 and its vicinity.

[0044] As shown in Figure 5A and Figure 5B , two kinds of treatment liquids are used for the formation of the surface treatment layer 12s. However, for comparison, the surface treatment layer 12s is not formed for several samples (Sample 1, 10, 20).

[0045] Treatment liquid 1 contains "Modiper FS700" (trade name) manufactured by Nippon Oil & Fats Co., Ltd. (Tokyo, Japan). "Modiper FS700" contains an acrylic silicone polymer and is a low-viscosity substance (low adhesion component). Treatment liquid 1 contains 8.6 parts by mass of diphenylmethane diisocyanate (MDI) manufactured by Nippon Polyurethane Industry Co., Ltd. (Tokyo, Japan), 2.6 parts by mass of trimethylolpropane (TMP) manufactured by Nippon Polyurethane Industry Co., Ltd., "Modiper FS700", and methyl ethyl ketone (MEK). The molecular weight of MDI is 250.25, and the molecular weight of TMP is 134.17.

[0046] Figure 5A and Figure 5B represents the ratio of the low adhesion component in treatment liquid 1. For samples 2 and 11, "MODIPER FS700" in treatment liquid 1 is 0.1 part by mass, MEK is 88.7 parts by mass, and the ratio of "MODIPER FS700" to the whole of treatment liquid 1 is 0.1 mass%. For sample 3, "MODIPER FS700" in treatment liquid 1 is 0.4 part by mass, MEK is 88.4 parts by mass, and the ratio of "MODIPER FS700" to the whole of treatment liquid 1 is 0.4 mass%.

[0047] Treatment liquid 2 relates to an embodiment of the present invention. Treatment liquid 2 is obtained by dissolving "Orgatix SIC-330" (trade name) manufactured by Matsumoto Fine Chemical Co., Ltd. (Chiba, Japan) in ethyl acetate as a solvent. "Orgatix SIC-330" contains isocyanate silane and is a low-viscosity substance (low adhesion component). Specifically, it contains 5 to 15 mass% of monomethyltriisocyanate silane (CH3Si(NCO3).

[0048] Figure 5A and Figure 5B represents the ratio of the low adhesion component in treatment liquid 2. For example, for sample 6, "Orgatix SIC-330" in treatment liquid 2 is 0.3 part by mass, ethyl acetate is 99.7 parts by mass, and the ratio of "Orgatix SIC-330" to the whole of treatment liquid 2 is 0.3 mass%.

[0049] By immersing the elastic member in treatment liquid 1 or treatment liquid 2 maintained at 23°C for 60 seconds, treatment liquid 1 or treatment liquid 2 penetrates the surface of elastic member 12. Then, by placing elastic member 12 in the internal space of an oven maintained at 50°C for 1 hour, elastic member 12 is heated to cure the surface treatment layer 12s. However, the curing method of the surface treatment layer 12s can be ventilation drying or natural drying.

[0050] Then, the elastic member 12 with the cured surface treatment layer 12s is bonded to the bracket 11 to complete each sample of the cleaning blade 10. On the other hand, the elastic member 12 without the surface treatment layer 12s is bonded to the bracket 11 to complete samples 1, 10, and 20 of the cleaning blade 10.

[0051] Before and after the formation of the surface treatment layer 12s, the indentation elastic modulus of the surface of the sample was measured. On the other hand, the indentation elastic modulus of the surface of samples 1, 10, and 20 without the surface treatment layer 12s was also measured. The indentation elastic modulus was measured according to ISO14577 using the "Dynamic Ultra Micro Hardness Tester DUH-211R" (trade name) manufactured by Shimadzu Corporation (Kyoto, Japan) in an environment of 23°C and 55% relative humidity through a load-unload test. The indenter used was a triangular pyramid indenter with a vertex angle of 115 degrees, and the vertex was pressed into the sample. Specifically, the indenter was pressed into the sample at a load rate of 0.14 mN / s until the load applied by the indenter to the sample reached the maximum load of 0.98 mN. After maintaining the maximum load for 5 seconds, the load was reduced at a load rate of -0.14 mN / s. The indentation depth of the indenter into the sample under the maximum load was 3 μm to 10 μm, which was less than or equal to the thickness t of the surface treatment layer 12s.

[0052] The indentation elastic modulus A, B of the surface of the sample before and after the formation of the surface treatment layer 12s and their difference A - B are shown in Figure 5A and Figure 5B . The indentation elastic modulus B of the surface of samples 1, 10, and 20 without the surface treatment layer 12s is also shown in Figure 5A and Figure 5B . It can be seen from Figure 5A and Figure 5B that in samples 2, 3, and 11, the indentation elastic modulus, that is, the hardness, increased significantly due to the formation of the surface treatment layer 12s. On the other hand, in samples 5 - 9, 12 - 19, 21, and 22, the indentation elastic modulus, that is, the hardness, decreased due to the formation of the surface treatment layer 12s. For sample 4, the indentation elastic modulus, that is, the hardness, did not change.

[0053] In addition, before and after the formation of the surface treatment layer 12s, the dynamic friction coefficient of the surface of the sample was measured. On the other hand, the dynamic friction coefficients of the surfaces of samples 1, 10, and 20 without the surface treatment layer 12s were also measured. The dynamic friction coefficient was measured in an environment with a temperature of 23°C and a relative humidity of 55% in accordance with JIS K7125 (ISO 8295) using a "HEIDON Friction and Wear Tester Tribogear" (trade name) manufactured by Shinto Kagaku Co., Ltd. (Tokyo, Japan). However, as the slider, a ball indenter made of stainless steel SUS304 with a diameter of 10 mm was used, and the load applied by the ball indenter to the sample was 0.98 N. The ball indenter was moved back and forth at a moving speed of 50 mm / min over a length of 50 mm to measure the dynamic friction coefficient.

[0054] The dynamic friction coefficients C and D of the surfaces of the samples before and after the formation of the surface treatment layer 12s and their ratio C / D are shown in Figure 5A and Figure 5B . The dynamic friction coefficients D of the surfaces of samples 1, 10, and 20 without the surface treatment layer 12s are also shown in Figure 5A and Figure 5B . From Figure 5A and Figure 5B , it can be seen that except for samples 1, 10, and 20 where the surface treatment layer 12s was not formed and sample 4 where the difference A - B was zero, in other samples, the dynamic friction coefficient can be significantly reduced by forming the surface treatment layer 12s. In other words, assuming the same surface roughness, the dynamic friction coefficient of the surface of the surface treatment layer 12s is significantly lower than that of the non-treated part 12n.

[0055] For each sample, the wear amount of the front end 13 of the elastic member 12 was measured through the following experiments shown in Figure 6 and Figure 7 . The wear amount was measured in an environment with a temperature of 23°C and a relative humidity of 55%. The length of the sample of the elastic member 12 was 14 mm, the protruding length L of the sample protruding from the end of the bracket 11 was 9 mm, and the thickness T of the sample was 2 mm. The width of the sample (the length in the direction perpendicular to the plane of the figure) was 50 mm. The angle α of the edge 14 (refer to Figure 2 ) was 90 degrees. Among them, the length L was measured when the elastic member 12 was straight.

[0056] As shown in Figure 6As shown, a packaging film 20 with a thickness of 0.3 μm is wound around the outer circumference of a rotatable cylinder 19. The cylinder 19 is formed by coating the surface of a glass material cylinder with polycarbonate, imitating the photosensitive drum 1. The abrasive film 20 is "Abrasive Film Abrasive Material #15000A3 - 0.3SHT" available from 3M Japan Co., Ltd. (Tokyo, Japan). The reason for winding the abrasive film 20 around the cylinder 19 is to accelerate the wear of the front end portion 13 of the elastic member 12 by the abrasive.

[0057] Next, the elastic member 12 of the cleaning blade 10 is brought into contact with the cylinder 19 wound with the packaging film 20 at a contact angle θ and a contact load of 0.18 N / cm. The contact angle θ is 20 degrees. Then, the cylinder 19 and the packaging film 20 are rotated together at a circumferential speed of 460 mm / s, and the packaging film 20 on the cylinder 19 is slid relative to the elastic member 12 by a distance of 1485 mm (the total length of 5 sheets of A4 size paper).

[0058] Then, the wear amount of the front end portion 13 of the elastic member 12 is measured. In the measurement of the wear amount, a laser microscope "VK - X250" (trade name) of Keyence Corporation (Osaka, Japan) is used, and an objective lens with a magnification of 150 times is used to photograph the edge 14 of the front end portion 13, and the area of the worn portion 22 is calculated in the photographed image. The photographing direction is inclined with respect to the longitudinal direction of the elastic member 12 ( Figure 7 the arrow P in shows the photographing direction), but through calculation correction, the area of the worn portion 22 observed from the direction orthogonal to the longitudinal direction of the elastic member 12 ( Figure 7 the direction of the arrow Q in) can be calculated. Photographing is performed at 3 locations in the longitudinal direction of the elastic member. The value obtained by averaging the areas obtained at the 3 locations is recorded in Figure 5A and Figure 5B .

[0059] According to the wear test results, for samples 1, 10, and 20 without surface treatment, the wear amount is 30 μm2 or more. In addition, for samples 2, 3, and 11 on which the surface treatment layer 12s is formed using treatment liquid 1, the wear amount is 28 μm2 or more, which is larger than that of samples 5 - 9, 12 - 19, 21, and 22. For samples 2, 3, and 11, through surface treatment (formation of the surface treatment layer 12s), the indentation elastic modulus of the surface increases (i.e., the surface is cured).

[0060] Therefore, it is preferable to form the surface treatment layer 12s using the treatment liquid 2 containing isocyanate silane. Among samples 5 to 9, 12 to 19, 21, and 22 in which the surface treatment layer 12s is formed using the treatment liquid 2 with a small wear amount, the indentation elastic modulus A of the surface of the surface treatment layer 12s varies. Additionally, for samples 4 and 5 in which the surface treatment layer 12s is formed using the treatment liquid 2, although the indentation elastic modulus A of the surface of the surface treatment layer 12s is close, the wear amounts are significantly different. Therefore, the reduction in the wear amount is not caused only by the indentation elastic modulus A of the surface of the surface treatment layer 12s.

[0061] Therefore, attention is paid to the difference between the indentation elastic modulus A of the surface of the surface treatment layer 12s and the indentation elastic modulus B of the surface before surface treatment. Considering samples 5 to 9, 12 to 19, 21, and 22, and further considering the difference in the wear amounts of samples 4 and 5, the difference A - B is preferably -0.01 MPa or less. This is contrary to the teachings of the prior art (Patent Documents 1 and 2), meaning that it is preferable to reduce the indentation elastic modulus of the surface (i.e., soften the surface) through surface treatment.

[0062] In this regard, the applicant makes the following investigation. In the case where the elastic modulus (i.e., hardness) of the surface of the edge 14 of the elastic member 12 is high, it has been conventionally considered that the wear of the edge 14 is small. However, in this case, the contact area between the photosensitive drum 1 and the elastic member 12 is small ( Figure 1 ). In the case of a small contact area, the stress concentrated on the edge 14 is large, which may cause fine cracking and peeling of the edge 14. However, in the case where the elastic modulus (i.e., hardness) of the surface of the edge 14 of the elastic member 12 is low, the contact area between the photosensitive drum 1 and the elastic member 12 is large, so the stress applied to the edge 14 is small, and the edge 14 is less likely to crack and peel.

[0063] At least the surface treatment layer 12s of the edge 14 and its vicinity thinly extends around the non-treated portion 12n with a higher elastic modulus. It is considered that if the difference between the indentation elastic modulus A of the surface of the surface treatment layer 12s and the indentation elastic modulus B (the indentation elastic modulus of the non-treated portion 12n) of the surface before surface treatment is appropriate, the stress applied to the edge 14 is small, and the edge 14 is not easily cracked and peeled. Based on the results of samples 5 to 9, 12 to 19, 21, and 22 and the difference in the wear amounts of samples 4 and 5, the value obtained by subtracting the indentation elastic modulus B of the non-treated portion (rubber portion) 12n from the indentation elastic modulus A of the surface of the surface treatment layer (surface layer) 12s is preferably -0.01 MPa or less. In the formation process of the surface treatment layer 12s, it is preferable to form the surface treatment layer 12s such that the value obtained by subtracting the indentation elastic modulus of the raw material made of polyurethane rubber before forming the surface treatment layer 12s from the indentation elastic modulus of the surface of the surface treatment layer 12s is -0.01 MPa or less.

[0064] Further, it is more preferably that the value obtained by subtracting the indentation elastic modulus B of the non-treated portion (rubber portion) 12n from the indentation elastic modulus A of the surface of the surface treatment layer (surface layer) 12s is -0.30 MPa or less. In the formation process of the surface treatment layer 12s, it is more preferably formed in such a manner that the value obtained by subtracting the indentation elastic modulus of the surface of the raw material made of polyurethane rubber before forming the surface treatment layer 12s from the indentation elastic modulus of the surface of the surface treatment layer 12s is -0.30 MPa or less. In this case, as in Samples 8, 9, 16 to 19, the wear amount can be made 20 μm2 or less.

[0065] The test is only carried out when the difference A - B is -5.31 MPa or more. However, when the difference A - B is smaller, it may also be possible to reduce the wear amount.

[0066] In addition, in addition to the above condition of the difference A - B ≤ -0.01 MPa, according to the results of Samples 5 to 9, 12 to 19, 21, 22 and the difference in wear amount between Samples 4 and 5, it is preferably that the ratio of the dynamic friction coefficient C of the surface of the surface treatment layer (surface layer) 12s to the dynamic friction coefficient D of the non-treated portion (rubber portion) 12n is 74% or less. In the formation process of the surface treatment layer 12s, it is preferably formed in such a manner that the ratio of the dynamic friction coefficient C of the surface of the surface treatment layer 12s to the dynamic friction coefficient D of the surface of the raw material made of polyurethane rubber before forming the surface treatment layer 12s is 74% or less.

[0067] Furthermore, in addition to the above condition of the difference A - B ≤ -0.01 MPa, considering Samples 5 to 9, 13 to 19, 21, 22, it is more preferably that the ratio of the dynamic friction coefficient C of the surface of the surface treatment layer (surface layer) 12s to the dynamic friction coefficient D of the non-treated portion (rubber portion) 12n is less than 21%. In the formation process of the surface treatment layer 12s, it is more preferably formed in such a manner that the ratio of the dynamic friction coefficient C of the surface of the surface treatment layer 12s to the dynamic friction coefficient D of the surface of the raw material made of polyurethane rubber before forming the surface treatment layer 12s is less than 21%. In this case, the wear amount can be made less than 24 μm2. The test is only carried out when the ratio C / D is 73% or more. However, when the ratio C / D is smaller, it may also be possible to reduce the wear amount.

[0068] Alternatively, in addition to the condition of the difference A - B ≤ about 0.01 MPa described above, when considering Samples 5 to 9 and 13 to 19, it is preferable that the kinetic friction coefficient C of the surface of the surface treatment layer (surface layer) 12s is less than 0.41. In the forming step of the surface treatment layer 12s, it is preferable to form the surface treatment layer 12s such that the kinetic friction coefficient C of the surface of the surface treatment layer 12s is less than 0.41. In this case, the wear amount can be made less than 24 μm2. The test is performed only when the kinetic friction coefficient C is 0.08 or more. However, it is also possible to reduce the wear amount when the kinetic friction coefficient C is smaller.

[0069] As described above, the present invention has been illustrated and described with reference to the preferred embodiments of the present invention. However, those skilled in the art should understand that various forms and details can be changed without departing from the scope of the invention described in the claims. Such changes, alterations, and modifications should be included within the scope of the present invention.

[0070] For example, in the above-described embodiment, the cleaning blade contacts the outer peripheral surface of the photosensitive drum 1 to clean the photosensitive drum 1. However, the cleaning blade of the present invention may contact the photoreceptor belt wound around a plurality of rollers instead of the photosensitive drum 1 to clean the belt.

[0071] Description of reference numerals:

[0072] 10 Cleaning blade

[0073] 11 Bracket (support member)

[0074] 12 Elastic member

[0075] 12s Surface treatment layer (surface layer)

[0076] 12n Non-treated portion (rubber portion)

[0077] 13 Front end portion

[0078] 14 Edge

Claims

1. A cleaning blade includes an elastic member having an edge that contacts a photoreceptor member. The elastic member has: a surface layer formed of a polyurethane rubber containing an isocyanate silane; and a rubber portion formed of a polyurethane rubber not containing an isocyanate silane, wherein the surface layer includes at least the edge, and a value obtained by subtracting an indentation elastic modulus of the rubber portion from an indentation elastic modulus of the surface of the surface layer is -0.01 MPa or less.

2. The cleaning blade according to claim 1, wherein, The value is -0.30 MPa or less.

3. The cleaning blade according to claim 1, wherein, The value is -5.31 MPa or more.

4. The cleaning blade according to any one of claims 1 to 3, wherein, A ratio of a dynamic friction coefficient of the surface of the surface layer to a dynamic friction coefficient of the rubber portion is 74% or less.

5. The cleaning blade according to claim 4, wherein, The ratio is less than 21%.

6. The cleaning blade according to claim 4, wherein, The ratio is 7% or more.

7. The cleaning blade according to any one of claims 1 to 3, wherein, The dynamic friction coefficient of the surface of the surface layer is less than 0.

41.

8. A method for manufacturing an elastic member of a cleaning blade, comprising a step of forming a surface treatment layer containing an isocyanate silane on a raw material made of a polyurethane rubber, wherein the step of forming the surface treatment layer has: a step of allowing a treatment liquid containing an isocyanate silane to penetrate into a region including at least a portion corresponding to an edge that contacts a photoreceptor member of the raw material; and a step of drying the treatment liquid, wherein the surface treatment layer is formed such that a value obtained by subtracting an indentation elastic modulus of the surface of the raw material before forming the surface treatment layer from an indentation elastic modulus of the surface of the surface treatment layer is -0.01 MPa or less.

9. The manufacturing method according to claim 8, wherein, When forming the surface treatment layer, the surface treatment layer is formed such that the value is -0.30 MPa or less.

10. The manufacturing method according to claim 8, wherein, When forming the surface treatment layer, the surface treatment layer is formed such that the value is -5.31 MPa or more.

11. The manufacturing method according to any one of claims 8 to 10, wherein, When forming the surface treatment layer, the surface treatment layer is formed such that a ratio of a dynamic friction coefficient of the surface of the surface treatment layer to a dynamic friction coefficient of the surface of the raw material before forming the surface treatment layer is 74% or less.

12. The manufacturing method according to claim 11, wherein, When forming the surface treatment layer, the surface treatment layer is formed such that the ratio is less than 21%.

13. The manufacturing method according to claim 11, wherein, When forming the surface treatment layer, the surface treatment layer is formed such that the ratio is 7% or more.

14. The manufacturing method according to any one of claims 8 to 10, wherein, When forming the surface treatment layer, the surface treatment layer is formed such that the dynamic friction coefficient of the surface of the surface treatment layer is less than 0.41.

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