Cleaning blade, cleaning device, process cartridge, and image forming apparatus

Abstract

To provide a cleaning blade that suppresses edge curling and wear, and produces images with reduced color streaks caused by poor cleaning. [Solution] A cleaning blade having a laminated structure including a surface layer and a back layer, wherein the surface layer and the back layer are made of polyurethane material, the 100% modulus of the surface layer is 10 MPa or more and 20 MPa or less, and when the thickness of the surface layer is Tc (mm) and the total thickness is [thickness of the surface layer + thickness of the back layer] Ts (mm), the region A from the end to 4.5% of the blade width satisfies the relationship 0.3 ≤ Tc / Ts ≤ 0.6, the central part B of the blade width satisfies the relationship 0.2 ≤ Tc / Ts ≤ 0.3, and the Tc / Ts of region A is greater than the Tc / Ts of the central part B.

Description

Technical Field

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

Background Art

[0002] In an image forming apparatus (such as a copier, a facsimile machine, a printer, etc.) using an electrophotographic method, a toner image formed on the surface of an image carrier is transferred onto the surface of a recording medium and fixed thereon to form an image.

[0003] For example, Patent Document 1 discloses "an image carrier on which an electrostatic latent image is formed, developing means for forming the electrostatic latent image on the image carrier into a toner image, a first blade member that contacts the image carrier and removes residual toner remaining on the image carrier, the first blade member having a first hardness treatment portion processed to have a high hardness provided at a longitudinal end portion on the side contacting the image carrier, an intermediate transfer member that transfers and holds the toner image from the image carrier, primary transfer means for primarily transferring the toner image on the image carrier to the intermediate transfer member in a primary transfer region, and a second blade member that contacts the intermediate transfer member and removes residual toner remaining on the intermediate transfer member, the second blade member having a second hardness treatment portion processed to have a high hardness provided at a longitudinal end portion on the side contacting the intermediate transfer member, and an image forming apparatus having the above, wherein in the longitudinal direction, the inner end portions of the first and second hardness treatment portions do not overlap, and the inner end portion of the second hardness treatment portion is located outside the inner end portion of the first hardness treatment portion."

[0004] Patent Document 2 describes an electrophotographic cleaning blade comprising an elastic member containing polyurethane and a support member for supporting the elastic member, wherein the elastic member contacts a part of the elastic member with the surface of a moving member to be cleaned to clean the surface of the member to be cleaned, and when the side of the cleaning blade that contacts the surface of the member to be cleaned is defined as the tip side of the cleaning blade, the elastic member has a plate shape having at least the tip side having a main surface facing the member to be cleaned and a tip surface that together with the main surface forms a tip edge, and when it is assumed that a first line segment is drawn on the tip surface parallel to the tip edge and at a distance of 10 μm from the tip edge, the length of the first line segment is L, and a point 1 / 2L from one end of the first line segment is P1, and a square region on the tip surface with P1 as its centroid, having a side length of 20 μm and one side parallel to the first line segment, is scanned using a scanning probe microscope at a scan speed of 1 Hz, with the number of scan points The area is scanned under the conditions of 256 vertical and 256 horizontal pixels, and a 256-level grayscale phase image is obtained as a viscoelastic image of the region. A binarized image is created in which the 93rd lowest level from the luminance frequency distribution obtained from the phase image is used as a threshold, and areas above the threshold are represented as black, and areas below the threshold are represented as white. Furthermore, the binarized image is divided into 100 sections of 2 μm square, and based on the area ratio of the white area in each section, the average value AM of the area ratio of the white area, and the standard deviation Σ of the area ratio of the white area, When the coefficient of variation of the area ratio of the white region is determined, the coefficient of variation is 20.00 or less, and the value obtained by subtracting the Martens hardness HM2 of the elastic member, measured at a distance of 500 μm from the tip edge on the bisector of the angle between the main surface and the tip surface, assuming that a bisector of the angle between the main surface and the tip surface is drawn on the cross section of the elastic member perpendicular to the tip surface and the tip edge including P1, from the Martens hardness HM1 of the elastic member measured at position P1 is 0.10 N / mm 2 A cleaning blade for electrophotography, characterized by being larger, is disclosed.

[0005] Patent Document 3 describes a developing apparatus comprising an image carrier, a developer carrier carrying a developer containing toner, and a cleaning blade for cleaning toner remaining on the image carrier, wherein the cleaning blade has a contact portion that contacts the image carrier, and the contact portion includes a first region located on the central side in the longitudinal direction of the cleaning blade, and regions provided on both ends of the cleaning blade adjacent to the first region in the longitudinal direction of the cleaning blade, and regions located inside the end of the developing region in which the developer carrier carries the developer, and having a higher hardness than the first region. An image forming apparatus is disclosed, comprising: a second region whose surface is hardened with an isocyanate compound, having a first step formed at the boundary with the first region and having a width in the thickness direction of the cleaning blade that is greater than that of the first region; and a third region provided on both ends of the cleaning blade adjacent to the second region in the longitudinal direction of the cleaning blade, having a surface hardened with an isocyanate compound to be harder than that of the second region, having a second step formed at the boundary with the second region and having a width in the thickness direction of the cleaning blade that is greater than that of the second region. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2012-252157 [Patent Document 2] Japanese Patent Publication No. 2022-076463 [Patent Document 1] Japanese Patent Publication No. 2022-083914 [Overview of the project] [Problems that the invention aims to solve]

[0007] The problem of this disclosure is to provide a cleaning blade that has a laminated structure including a surface layer and a back layer, wherein the surface layer and the back layer are made of polyurethane material, the 100% modulus of the surface layer is 10 MPa or more and 20 MPa or less, and when the thickness of the surface layer is Tc (mm) and the total thickness [thickness of the surface layer + thickness of the back layer] Ts (mm), the region A from the edge to 4.5% of the blade width satisfies the relationship 0.3 > Tc / Ts or Tc / Ts > 0.6, and the central part B of the blade width satisfies the relationship 0.2 ≤ Tc / Ts ≤ 0.3, thereby suppressing edge peeling and wear, and providing an image in which the occurrence of color streaks due to poor cleaning is suppressed. [Means for solving the problem]

[0008] The means for solving the above problems include the following embodiments. <1> It has a laminated structure including a surface layer and a back layer, The surface layer and the back layer are made of polyurethane material. The 100% modulus of the aforementioned surface layer is 10 MPa or more and 20 MPa or less. A cleaning blade in which, when the thickness of the surface layer is Tc (mm) and the total thickness is [thickness of the surface layer + thickness of the back layer] Ts (mm), the region A from the end to 4.5% of the blade width satisfies the relationship 0.3 ≤ Tc / Ts ≤ 0.6, the central part B of the blade width satisfies the relationship 0.2 ≤ Tc / Ts ≤ 0.3, and the Tc / Ts of region A is greater than the Tc / Ts of the central part B. <2> The region A satisfies the relationship 0.45 ≤ Tc / Ts ≤ 0.55. <1> The cleaning blade described above. <3> The central part B satisfies the relationship 0.225 ≤ Tc / Ts ≤ 0.275. <1> The cleaning blade described above. <4> The region A satisfies the relationship 0.45 ≤ Tc / Ts ≤ 0.55, and the central region B satisfies the relationship 0.225 ≤ Tc / Ts ≤ 0.275. <1> The cleaning blade described above. <5> The 100% modulus of the surface layer is 12.5 MPa or more and 17.5 MPa or less. <1> The cleaning blade described above. <6> The 100% modulus of the surface layer is 12.5 MPa or more and 17.5 MPa or less, the region A satisfies the relationship 0.45 ≤ Tc / Ts ≤ 0.55, and the central part B satisfies the relationship 0.225 ≤ Tc / Ts ≤ 0.275. <1> The cleaning blade described above. <7> The permanent elongation of the aforementioned surface layer is 4% or less. <1> ~ <6> A cleaning blade as described in one of the following. <8> The aforementioned back layer has a 100% modulus of 4 MPa to 7 MPa and a permanent elongation of 2% or less. <1> ~ <7> A cleaning blade as described in one of the following. <9> <1> ~ <8> A cleaning device equipped with a cleaning blade as described in any one of the following. <10> <9> A process cartridge equipped with the cleaning device described above, which is detachable from the image forming apparatus. <11> Image holder and, A charging device for charging the image holder, An electrostatic latent image forming apparatus for forming an electrostatic latent image on the surface of the charged image holder, A developing apparatus that develops an electrostatic latent image formed on the surface of the image holder with toner to form a toner image, A transfer device for transferring a toner image formed on the surface of the image holder onto a recording medium, The cleaning blade is brought into contact with the surface of the image holder to clean the surface of the image holder. <9> The cleaning device described above, An image forming apparatus equipped with the following features. [Effects of the Invention]

[0009] <1> According to the invention, a cleaning blade is provided that has a laminated structure including a surface layer and a back layer, wherein the surface layer and the back layer are made of polyurethane material, the 100% modulus of the surface layer is 10 MPa or more and 20 MPa or less, and when the thickness of the surface layer is Tc (mm) and the total thickness [thickness of the surface layer + thickness of the back layer] Ts (mm), compared to the case where the region A from the edge to 4.5% of the blade width satisfies the relationship 0.3 > Tc / Ts or Tc / Ts > 0.6, and the central part B of the blade width satisfies the relationship 0.2 ≤ Tc / Ts ≤ 0.3, the cleaning blade is provided that suppresses edge peeling and wear and suppresses the occurrence of color streaks due to poor cleaning, resulting in an image.

[0010] <2> , <4> , or <6> According to the invention, a cleaning blade is provided that suppresses edge peeling and wear, and suppresses the occurrence of color streaks due to poor cleaning, compared to the case where region A does not satisfy the relationship 0.45 ≤ Tc / Ts ≤ 0.55. <3> , <4> , or <6> According to the invention, a cleaning blade is provided that can produce an image in which the occurrence of color streaks due to poor cleaning is suppressed compared to the case where the central part B does not satisfy the relationship 0.225 ≤ Tc / Ts ≤ 0.275. <5> According to the invention, compared to cases where the 100% modulus of the surface layer is less than 12.5 MPa or greater than 17.5 MPa, a cleaning blade is provided that suppresses edge peeling and wear, and suppresses the occurrence of color streaks due to poor cleaning, resulting in an image.

[0011] <7> According to the invention, a cleaning blade is provided that can produce an image in which the occurrence of color streaks due to poor cleaning is suppressed compared to the case where the permanent elongation of the surface layer exceeds 4%. <8> According to the invention, a cleaning blade is provided that suppresses edge peeling and wear, and reduces the occurrence of color streaks due to poor cleaning, compared to cases where the 100% modulus of the back layer is less than 4 MPa or greater than 7 MPa, resulting in an image with reduced edge peeling and wear.

[0012] According to the invention according to <9>, <10> or <11>, it has a laminated structure including a surface layer and a back layer, the surface layer and the back layer are composed of polyurethane members, the 100% modulus of the surface layer is 10 MPa or more and 20 MPa or less, when the thickness of the surface layer is Tc (mm) and the total thickness [the thickness of the surface layer + the thickness of the back layer] is Ts (mm), the region A from the end to 4.5% of the blade width satisfies the relationship of 0.3 > Tc / Ts or Tc / Ts > 0.6, compared with the case where the central portion B of the blade width satisfies the relationship of 0.2 ≤ Tc / Ts ≤ 0.3, an image is obtained in which end curling and wear are suppressed and the generation of color streaks due to poor cleaning is suppressed, and a cleaning device, a process cartridge, or an image forming apparatus including a cleaning blade is provided.

Brief Description of the Drawings

[0013] [Figure 1] It is a schematic diagram showing an example of the cleaning blade according to the present embodiment. [Figure 2] It is a schematic diagram showing an example of the image forming apparatus according to the present embodiment. [Figure 3] [[ID=​​​​​​​​​​​​​In this embodiment, the term "process" includes not only independent processes but also any process that cannot be clearly distinguished from other processes, as long as its intended purpose is achieved. In this embodiment, when describing embodiments with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. Furthermore, the sizes of the members in each figure are conceptual, and the relative relationships between the sizes of the members are not limited thereto. In this embodiment, each component may contain multiple types of the corresponding substance. In this embodiment, when referring to the amount of each component in the composition, if there are multiple types of the substance corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of those multiple types of substances present in the composition.

[0016] <Cleaning Blade> The cleaning blade according to this embodiment has a laminated structure including a surface layer and a back layer, the surface layer and the back layer are made of polyurethane material, the 100% modulus of the surface layer is 10 MPa or more and 20 MPa or less, when the thickness of the surface layer is Tc (mm) and the total thickness is [thickness of the surface layer + thickness of the back layer] Ts (mm), the region A from the end to 4.5% of the blade width satisfies the relationship 0.3 ≤ Tc / Ts ≤ 0.6, the central part B of the blade width satisfies the relationship 0.2 ≤ Tc / Ts ≤ 0.3, and the Tc / Ts of region A is greater than the Tc / Ts of the central part B.

[0017] In the cleaning blade according to this embodiment, the surface layer is a layer that contacts the image holder, which is the member to be cleaned, and the back layer is a layer that does not contact the image holder, which is the member to be cleaned. Hereafter, "area A from the end to 4.5% of the blade width" will also be simply referred to as "area A," and "the central part B of the blade width" will also be simply referred to as "central part B."

[0018] Normally, in image areas where toner is present on the image holder (e.g., photoreceptor), the friction coefficient with the cleaning blade is reduced due to the lubricating components (silica, zinc stearate, etc.) of the toner's external additives, thereby reducing the load on the cleaning blade. As a result, in the aforementioned image areas, the retraction of the cleaning blade tip and stick-and-slip behavior are suppressed, and the peeling and wear of the cleaning blade are less likely to be accelerated. On the other hand, in non-image areas on the image holder, the lubricating components of the toner's external additives are not supplied, resulting in a higher coefficient of friction between these non-image areas and the ends of the blade in the width direction (also called the longitudinal direction or axial direction) that come into contact with them. Consequently, the ends of the blade in the width direction tend to show peeling or wear more severely. Therefore, in order to suppress the peeling of the cleaning blade and improve its wear resistance, a method has been proposed to increase the hardness of the cleaning blade's surface across its entire width. In addition, a method has been proposed to reduce the coefficient of friction by surface-treating only the ends of the cleaning blade in the width direction. However, even these methods are insufficient to suppress curling (also known as edge curling) and wear at the widthwise ends of the blade, and to obtain images that also suppress the occurrence of color streaks due to poor cleaning.

[0019] The cleaning blade according to this embodiment, with the above configuration, suppresses edge curling and wear, and produces images with reduced color streaks due to poor cleaning. The reason for this is presumed to be as follows. The cleaning blade according to this embodiment has a surface layer with a 100% modulus of 10 MPa to 20 MPa. The ratio Tc / Ts of the surface layer thickness to the total thickness of the cleaning blade [thickness of the surface layer + thickness of the back layer] Ts (mm) is set so that the ends are larger than the center of the blade width. Here, "region A from the end to 4.5% of the blade width" corresponds to the region that contacts the non-image region on the image holder. Also, "the center of the blade width B" corresponds to the region that contacts the image region on the image holder. In this way, for the high modulus surface layer, by making the thickness of the region that contacts the non-image region on the image holder greater than the thickness of the region that contacts the image region on the image holder, the tip behavior of the cleaning blade can be stabilized and retraction can be suppressed. As a result, it is presumed that edge peeling and wear will be suppressed, and an image with suppressed color streaks due to poor cleaning will be obtained.

[0020] The details of the cleaning blade according to this embodiment will be described below.

[0021] An example of a cleaning blade according to this embodiment will be described with reference to Figure 1. As shown in Figure 1, the cleaning blade 10 has a laminated structure consisting of a surface layer 12 and a back layer 14. In Figure 1, the X direction represents the width of the blade, the Y direction represents the thickness of the blade, and the Z direction represents the height of the blade. The thickness of the surface layer 12 is represented by Tc, and the total thickness, i.e., the thickness of the surface layer Tc + the thickness of the back layer, is represented by Ts. Furthermore, the cleaning blade 10 has a region A at both ends, extending from the edge to 4.5% of the blade width, and a central region B in the middle of the blade width. In addition, the cleaning blade 10 has two regions C between region A and central region B, which are regions connecting the two.

[0022] [100% Modulus of the Surface Layer] In the cleaning blade according to this embodiment, the 100% modulus of the surface layer is 10 MPa or more and 20 MPa or less. The 100% modulus of the surface layer is preferably 12.5 MPa to 17.5 MPa, more preferably 13.0 MPa to 17.0 MPa, and even more preferably 13.5 MPa to 16.5 MPa, from the viewpoint of suppressing edge peeling and wear, and obtaining an image in which the occurrence of color streaks due to poor cleaning is suppressed.

[0023] The 100% modulus of the surface layer is measured as follows: First, the cleaning blade is separated into a surface layer and a back layer using a laser cutter or an analytical single-edged knife. The separated surface layer is then measured at a tensile speed of 500 mm / min using a dumbbell-shaped No. 3 test specimen prepared in accordance with JIS K 6251:2010, and the 100% modulus is determined from the stress at 100% strain. The measurements are performed in a 23°C environment. The 100% modulus of the back layer, as described later, is determined using the back layer separated from the surface layer, in the same manner as described above.

[0024] Furthermore, the 100% modulus of the surface layer can be adjusted by selecting the type and amount of each polymerization component of the polyurethane, as well as the manufacturing conditions. Specifically, for example, the 100% modulus of the surface layer can be adjusted by the crosslinking density of the polyurethane (more specifically, the amount of polyisocyanate). Furthermore, the 100% modulus of the back layer, as described later, can be adjusted by selecting the type and amount of each polymerization component of polyurethane, as well as the manufacturing conditions, similar to the surface layer.

[0025] [Tc / Ts] In this embodiment, when the thickness of the surface layer is Tc (mm) and the total thickness [thickness of the surface layer + thickness of the back layer] Ts (mm), the cleaning blade satisfies the relationship 0.3 ≤ Tc / Ts ≤ 0.6 in region A from the end to 4.5% of the blade width, and the central part B of the blade width satisfies the relationship 0.2 ≤ Tc / Ts ≤ 0.3, and the Tc / Ts of region A is greater than the Tc / Ts of central part B. From the perspective of suppressing end curling and wear, and also from the perspective of obtaining an image in which the occurrence of color streaks due to poor cleaning is suppressed, it is preferable that region A satisfies the relationship of 0.4 ≦ Tc / Ts ≦ 0.6, and more preferably satisfies the relationship of 0.45 ≦ Tc / Ts ≦ 0.55. Also, from the perspective of suppressing end curling and wear, and also from the perspective of obtaining an image in which the occurrence of color streaks due to poor cleaning is suppressed, it is preferable that the central part B satisfies the relationship of 0.225 ≦ Tc / Ts ≦ 0.275. From the above, from the perspective of suppressing end curling and wear, and also from the perspective of obtaining an image in which the occurrence of color streaks due to poor cleaning is suppressed, it is preferable that region A satisfies the relationship of 0.45 ≦ Tc / Ts ≦ 0.55, and the central part B satisfies the relationship of 0.225 ≦ Tc / Ts ≦ 0.275. The Tc / Ts of region A is denoted as "A(Tc / Ts)", and the Tc / Ts of the central part B is also denoted as "B(Tc / Ts)".

[0026] Note that region C connecting region A from the end to 4.5% of the blade width and the central part B of the blade width corresponds to the region that contacts the image region on the image holding body. It is preferable that the Tc / Ts of this region C (denoted as "C(Tc / Ts)") increases continuously or stepwise from the central part B towards region A. Also, the Tc / Ts of region C preferably satisfies the range that it is not less than the Tc / Ts of the central part B and is smaller than the Tc / Ts of region A. That is, it is preferable to satisfy B(Tc / Ts) ≦ C(Tc / Ts) < A(Tc / Ts).

[0027] Note that the total thickness [thickness of the surface layer + thickness of the back layer] Ts is preferably 1.8 mm or more and 2.2 mm or less, more preferably 1.9 mm or more and 2.1 mm or less, and still more preferably 1.95 mm or more and 2.05 mm or less.

[0028] The surface layer thickness Tc and the total thickness [surface layer thickness + back layer thickness] Ts are measured as follows. Note that since the total thickness Ts corresponds to the overall thickness of the blade, the overall thickness of the blade may be measured and that value may be used as the total thickness. The blade is cut along the thickness direction to obtain a sample. The cross-section of the sample is observed using a Keyence VK-9500 laser microscope, and the thickness of each region A and region C is measured at three locations from the observed image. The arithmetic mean of these measurements is defined as the surface layer thickness Tc and total thickness Ts for regions A and C. In addition, the thickness of the central part B is measured at one location, and this measurement is defined as the surface layer thickness Tc and total thickness Ts.

[0029] Based on the above, it is preferable that the cleaning blade according to this embodiment has a surface layer with a 100% modulus of 12.5 MPa or more and 17.5 MPa or less, with region A satisfying the relationship 0.45 ≤ Tc / Ts ≤ 0.55 and the central portion B satisfying the relationship 0.225 ≤ Tc / Ts ≤ 0.275.

[0030] [Permanent stretching of the surface layer] In the cleaning blade according to this embodiment, the permanent elongation of the surface layer is preferably 4% or less, and more preferably 3% or less. For example, a lower limit for the permanent elongation of the surface layer is 2%.

[0031] Permanent elongation is measured as follows: First, the cleaning blade is separated into a surface layer and a back layer using a laser cutter or an analytical single-edged knife. For the separated surface layer, a strip-shaped test piece prepared in accordance with JIS K 6273:2018 is used, and a 100% tensile strain is applied and left for 24 hours. The permanent elongation Ts is then determined from the distance between the gauge marks using the following formula. Formula: Ts = (L2 - L0) / (L1 - L0) × 100 Ts: Permanent growth L0: Distance between gauge marks before tensioning L1: Distance between gauge marks when tensile L2: Distance between gauge marks after tensioning Furthermore, the permanent elongation of the back layer, as described later, is determined using the back layer separated from the surface layer, in the same manner as described above.

[0032] Furthermore, the permanent elongation of the surface layer can be adjusted, for example, by the amount of crosslinking agent, the molecular weight of the polyol, etc. Furthermore, the permanent elongation of the back layer, as described later, can be adjusted in the same way as the surface layer, for example, by the amount of crosslinking agent, the molecular weight of the polyol, etc.

[0033] [Preferred physical properties of the back layer] In the cleaning blade according to this embodiment, the back layer preferably has the following physical properties. For example, the 100% modulus of the back layer is preferably 3 MPa to 8 MPa, and more preferably 4 MPa to 7 MPa. Furthermore, the permanent elongation of the back layer is preferably 2% or less, and more preferably 0.7% or less. For example, the lower limit of the permanent elongation of the back layer is 0.5%. Based on the above, it is preferable that the back layer has a 100% modulus of 4 MPa to 7 MPa and a permanent elongation of 2% or less.

[0034] [Structure of each layer] In the cleaning blade according to this embodiment, the surface layer and the back layer are made of polyurethane material. The polyurethane constituting the polyurethane component is a polyurethane obtained by polymerizing at least a polyol component and a polyisocyanate component. The polyurethane may also be a polyurethane obtained by polymerizing a resin having functional groups that can react with the isocyanate groups of the polyisocyanate, in addition to the polyol component, as needed.

[0035] The polyurethane component preferably has hard segments and soft segments. "Hard segments" and "soft segments" refer to segments in the polyurethane material where the material constituting the former is relatively harder than the material constituting the latter, and the material constituting the latter is relatively softer than the material constituting the former. The materials that make up the hard segment (hard segment material) include low molecular weight polyols, polyisocyanates, and resins having functional groups that can react with isocyanate groups among the polyol components. On the other hand, the materials that make up the soft segment (soft segment material) include high molecular weight polyols among the polyol components.

[0036] • Polyol components The polyol component includes both high molecular weight polyols and low molecular weight polyols.

[0037] High molecular weight polyols are polyols with a number average molecular weight of 500 or more (preferably 500 to 5000). Examples of high molecular weight polyols include well-known polyols such as polyester polyols obtained by dehydration condensation of low molecular weight polyols and dibasic acids, polycarbonate polyols obtained by reaction of low molecular weight polyols and alkyl carbonates, polycaprolactone polyols, and polyether polyols. Examples of commercially available high molecular weight polyols include Praxel 205 and Praxel 240 manufactured by Daicel Corporation.

[0038] Here, the number-average molecular weight is the value measured by gel permeation chromatography (GPC). The same applies hereafter.

[0039] These polymeric polyols may be used individually or in combination of two or more types.

[0040] The polymerization ratio of the polymer polyol can be appropriately determined to obtain the above-mentioned physical properties in both the surface layer and the back layer. For example, when obtaining a surface layer, the polymerization ratio of the polymer polyol is preferably 23 mol% to 50 mol%, and more preferably 42.5 mol% to 47.5 mol%, relative to the total polyol component of the polyurethane. Furthermore, when obtaining a back layer, the polymerization ratio of the high-molecular-weight polyol is preferably 50 mol% to 60 mol% of the total polyol component of the polyurethane. In this specification, "total polyol components" refers to the total amount of polyol components used to obtain polyurethane, i.e., high-molecular-weight polyols and low-molecular-weight polyols. However, this total excludes low-molecular-weight polyols used as crosslinking agents. Low-molecular-weight polyols used as crosslinking agents refer to low-molecular-weight polyols used in amounts of 4.5 mol% or less relative to the total amount of low-molecular-weight polyols. In other words, low-molecular-weight polyols used in amounts of 4.5 mol% or less relative to the total amount of low-molecular-weight polyols are used as crosslinking agents and are excluded from "total polyol components".

[0041] Low molecular weight polyols are polyols with a molecular weight (number average molecular weight) of less than 500. Low molecular weight polyols are materials that function as chain length extenders and / or crosslinking agents.

[0042] Examples of low molecular weight polyols include diols (bifunctional), triols (trifunctional), and tetraols (tetrafunctional), which are well known as chain length extenders and / or crosslinking agents. Examples of diols include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,20-eicosanediol, ethylene glycol, diethylene glycol, neopentyl glycol, and diisopropanolamine. Examples of triols or tetraols include trimethylolpropane, glycerin, diglycerin, triisopropanolamine, triethanolamine, and pentaerythritol.

[0043] Among these, 1,4-butanediol is preferred as the low molecular weight polyol. Furthermore, it is preferable to use a combination of a diol and a triol as the low molecular weight polyol. In this case, trimethylolpropane is preferred as the triol used in combination.

[0044] These low-molecular-weight polyols may be used individually or in combination of two or more types.

[0045] The polymerization ratio of the low molecular weight polyol can be appropriately determined to obtain the above-mentioned physical properties in both the surface layer and the back layer. For example, when obtaining a surface layer, the polymerization ratio of low molecular weight polyols (excluding low molecular weight polyols used as crosslinking agents) is preferably 50 mol% to 77 mol%, and more preferably 52.5 mol% to 57.5 mol%, relative to the total polyol components of the polyurethane. Furthermore, when obtaining a back layer, the polymerization ratio of low molecular weight polyols (excluding low molecular weight polyols used as crosslinking agents) is preferably 40 mol% to 50 mol% of the total polyol components of the polyurethane. When obtaining a surface layer, the polymerization ratio of the low molecular weight polyol used as a crosslinking agent is preferably 0.4 mol% or more and 1.5 mol% or less relative to the total polyol component. When obtaining a back layer, the polymerization ratio of the low molecular weight polyol used as a crosslinking agent is preferably 1.5 mol% or more and 1.8 mol% or less relative to the total polyol component.

[0046] Polyisocyanate Examples of polyisocyanates include 4,4'-diphenylmethane diisocyanate (MDI), 2,6-toluene diisocyanate (TDI), 1,6-hexane diisocyanate (HDI), 1,5-naphthalene diisocyanate (NDI), and 3,3'-dimethylbiphenyl-4,4'-diisocyanate (TODI).

[0047] Among these, 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), and hexamethylene diisocyanate (HDI) are preferred as polyisocyanates.

[0048] These polyisocyanates may be used individually or in combination of two or more types.

[0049] The polymerization ratio of the polyisocyanate can be appropriately determined to obtain the above-mentioned physical properties in both the surface layer and the back layer. For example, when obtaining a surface layer, the polymerization ratio of the polyisocyanate is preferably 21 mol% to 33 mol%, and more preferably 23 mol% to 30 mol%, relative to the total polyol components. Furthermore, when obtaining a back layer, the polymerization ratio of the polyisocyanate is preferably 15 mol% to 23 mol% relative to the total polyol components.

[0050] • Resins having functional groups that can react with isocyanate groups Resins having functional groups that can react with isocyanate groups (hereinafter referred to as "functional group-containing resins") are preferably flexible resins, and more preferably aliphatic resins having a linear structure from the viewpoint of flexibility. Specific examples of functional group-containing resins include acrylic resins containing two or more hydroxyl groups, polybutadiene resins containing two or more hydroxyl groups, and epoxy resins containing two or more epoxy groups.

[0051] Examples of commercially available acrylic resins containing two or more hydroxyl groups include Actflow (grades: UMB-2005B, UMB-2005P, UMB-2005, UME-2005, etc.) manufactured by Soken Chemical Co., Ltd.

[0052] Examples of commercially available polybutadiene resins containing two or more hydroxyl groups include R-45HT, manufactured by Idemitsu Kosan Co., Ltd.

[0053] The epoxy resin having two or more epoxy groups is preferably one that is more flexible and tough than conventional epoxy resins, rather than having the hard and brittle properties of conventional epoxy resins. For example, in terms of molecular structure, the epoxy resin preferably has a structure (flexible skeleton) in its main chain that allows for high main chain mobility. Examples of flexible skeletons include alkylene skeletons, cycloalkane skeletons, and polyoxyalkylene skeletons, with polyoxyalkylene skeletons being particularly preferred. Furthermore, in terms of physical properties, epoxy resins with a lower viscosity relative to their molecular weight are preferred compared to conventional epoxy resins. Specifically, it is desirable that the weight-average molecular weight is within the range of 900 ± 100 and the viscosity at 25°C is within the range of 15000 ± 5000 mPa·s, and more preferably within the range of 15000 ± 3000 mPa·s. Examples of commercially available epoxy resins having these characteristics include EPICLON EXA-4850-150 manufactured by DIC Corporation.

[0054] The polymerization ratio of the functional group-containing resin should be within a range that does not impair the properties of the cleaning blade.

[0055] • Manufacturing of cleaning blades The manufacturing method for the polyurethane component constituting the cleaning blade according to this embodiment can be a general polyurethane manufacturing method such as the prepolymer method or the one-shot method. While the prepolymer method is preferred in this embodiment because it yields polyurethane with excellent strength and abrasion resistance, the invention is not limited to this method. Furthermore, the manufacturing method of the cleaning blade according to this embodiment is not particularly limited, as long as a laminated structure having the surface layer and back layer described above can be obtained.

[0056] The cleaning blade according to this embodiment is manufactured, for example, by the following method. In other words, the manufacturing method involves using a mixture of a prepolymer consisting of polyisocyanate and high-molecular-weight polyol, and a curing agent consisting of low-molecular-weight polyol (chain length extender, crosslinking agent) and a catalyst, and then pouring the mixture into a centrifugal molding drum or mold and heating it. Alternatively, the manufacturing method may involve using a composition containing polyisocyanate, high molecular weight polyol, low molecular weight polyol, and a catalyst, and then casting it into a centrifugal molding drum or a mold and heating it. Furthermore, the heat-molded components may be subjected to cutting or other processing as needed.

[0057] Alternatively, a laminated structure of a surface layer and a back layer may be obtained by preparing a composition for forming a surface layer (hereinafter also referred to as the surface layer composition) and a composition for forming a back layer (hereinafter also referred to as the back layer composition), sequentially pouring each composition into a mold, and then heat-molding it. In this case, it is preferable to pour the back layer composition into the center of the mold in the centrifugal molding machine, heat the mold to a high temperature to heat-cur the back layer composition before it levels (before it is leveled), and then pour the surface layer composition onto the cured back layer composition. The mold temperature when curing the back layer composition is preferably, for example, 140°C to 160°C, and more preferably 150°C to 158°C. Furthermore, it is preferable to heat the back layer composition immediately after pouring it in.

[0058] Examples of catalysts used in the production of polyurethane include amine compounds such as tertiary amines, quaternary ammonium salts, and organometallic compounds such as organotin compounds. Examples of the above-mentioned tertiary amines include trialkylamines such as triethylamine, tetraalkyldiamines such as N,N,N',N'-tetramethyl-1,3-butanediamine, amino alcohols such as dimethylethanolamine, ethoxylated amines, ethoxylated diamines, esteramines such as bis(diethylethanolamine)adipate, cyclohexylamine derivatives such as triethylenediamine (TEDA) and N,N-dimethylcyclohexylamine, morpholine derivatives such as N-methylmorpholine and N-(2-hydroxypropyl)-dimethylmorpholine, and piperazine derivatives such as N,N'-diethyl-2-methylpiperazine and N,N'-bis-(2-hydroxypropyl)-2-methylpiperazine.

[0059] Examples of quaternary ammonium salts include 2-hydroxypropyltrimethylammonium octylate, 1,5-diazabicyclo[4.3.0]nonene-5(DBN)octylate, 1,8-diazabicyclo[5.4.0]undecene-7(DBU)octylate, DBU oleate, DBU-p-toluenesulfonate, DBU formate, and 2-hydroxypropyltrimethylammonium formate.

[0060] Examples of organotin compounds include dialkyltin compounds such as dibutyltin dilaurate and dibutyltin di(2-ethylhexoate), as well as stannous 2-ethylcaproate and stannous oleate.

[0061] Among these catalysts, triethylenediamine (TEDA), a tertiary ammonium salt, is preferred in terms of hydrolysis resistance, while quaternary ammonium salts are preferred in terms of processability. Among quaternary ammonium salts, 1,5-diazabicyclo[4.3.0]nonene-5(DBN)·octylate, 1,8-diazabicyclo[5.4.0]undecene-7(DBU)-octylate, and DBU-formate are preferred due to their high reaction activity.

[0062] These catalysts can be used individually or in combination of two or more. The catalyst content is preferably in the range of 0.0005% by mass or more and 0.03% by mass or less of the total polyurethane, and particularly preferably 0.001% by mass or more and 0.01% by mass or less.

[0063] (impregnated hardened layer) In the cleaning blade according to this embodiment, the surface layer may be an impregnated and hardened layer of an isocyanate compound. The impregnated hardened layer is preferably an impregnated hardened layer of an isocyanate compound and a modified acrylic polymer (preferably a silicone-modified acrylic polymer) in order to improve the lubrication function of the blade. Here, the impregnated hardened layer may be present on the entire surface of the blade, i.e., the front layer and the back layer. The surface layer where the impregnated hardened layer is formed refers to the region from the surface to a depth of 100 μm.

[0064] The impregnated and cured layer is formed by impregnating the surface layer or the entire blade of a cleaning blade with an impregnation treatment solution containing, for example, an isocyanate compound and an organic solvent, or an impregnation treatment solution containing an isocyanate compound, a modified acrylic polymer, and an organic solvent, and curing the isocyanate compound, or the isocyanate compound and the modified acrylic polymer. As a result, the impregnated hardened layer becomes progressively less dense from the surface inward, with respect to the surface layer of each layer. It is formed as a single unit.

[0065] Examples of isocyanate compounds include 2,6-tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), paraphenylenedi diisocyanate (PPDI), 1,5-naphthalene diisocyanate (NDI), and 3,3'-dimethyldiphenyl-4,4'-diisocyanate (TODI), as well as their polymers and modified forms. Examples of modified isocyanate compounds include urethane prepolymers in which isocyanate compounds are prepolymerized together with polyols.

[0066] Examples of modified acrylic polymers include silicone-modified (meth)acrylic polymers (i.e., (meth)acrylic polymers having siloxane bonds) and (meth)acrylic polymers having fluorine atoms. Among these, from the viewpoint of improving the lubrication function of the blade, silicone-modified (meth)acrylic polymer is preferred as the modified acrylic polymer, and silicone-modified acrylic polymer is more preferred. Examples of silicone-modified (meth)acrylic polymers include block copolymers of (meth)acrylic acid esters and (meth)acrylic acid siloxane esters, and their derivatives. Examples of (meth)acrylic polymers containing a fluorine atom include block copolymers of (meth)acrylic acid esters and alkyl fluoride (meth)acrylic acid, and their derivatives. Note that "(meth)acrylic" means either acrylic or methacrylic, or both.

[0067] Here, the content of the modified (meth)acrylic polymer in the impregnation curing solution is 8 parts by mass or more and 13 parts by mass or less per 100 parts by mass of the isocyanate compound, preferably 9 parts by mass or more and 13 parts by mass or less, and more preferably 10 parts by mass or more and 13 parts by mass or less.

[0068] Examples of organic solvents include ethyl acetate, methyl ethyl ketone (MEK), toluene, acetone, and cyclohexanone. Reactive diluents such as 2-hydroxyethyl acrylate, tetrahydrofurfuryl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate, neopentyl glycol diacrylate, hexanediol diacrylate, and trimethylolpropane triacrylate may also be used as organic solvents.

[0069] For example, the impregnation and curing layer is formed by impregnating and coating at least the surface layer of the cleaning blade with the above-mentioned impregnation and curing liquid, removing the organic solvent by drying, and then forming the cured layer by heat treatment. The impregnation treatment is not particularly limited, and conventional coating methods such as blade coating, wire bar coating, spray coating, immersion coating, bead coating, air knife coating, and curtain coating can be applied. If the impregnation treatment is by immersion coating, the immersion time can be in the range of 10 seconds to 60 seconds, for example. Examples of drying conditions after impregnation include a temperature of 20°C to 30°C and a time of 1 minute to 10 minutes. Examples of heat treatment conditions include a temperature of 50°C to 80°C and a time of 60 minutes to 90 minutes.

[0070] (Uses of cleaning blades) When cleaning a member to be cleaned using the cleaning blade according to this embodiment, the member to be cleaned is preferably an image holder (for example, a photoreceptor) in an image forming apparatus. In addition, other members to be cleaned by the cleaning blade according to this embodiment include, for example, an intermediate transfer body, a charging roll, a transfer roll, a transfer material conveying belt, a paper conveying roll, and a detonating roll that further removes toner from the cleaning brush that removes toner from the image holder. Furthermore, the cleaning blade according to this embodiment may be used to clean members other than those for an image forming apparatus.

[0071] <Cleaning equipment, process cartridges, and image forming apparatus> The cleaning device of this embodiment is not particularly limited as long as it is equipped with the cleaning blade of this embodiment as a cleaning blade that contacts the surface of the member to be cleaned and cleans the surface of the member to be cleaned. For example, an example of the configuration of the cleaning device is a cleaning case having an opening on the side of the member to be cleaned, in which the cleaning blade is fixed so that the leading edge of the surface layer faces the opening, and a transport member is provided to guide foreign matter such as waste toner recovered from the surface of the member to be cleaned by the cleaning blade to a foreign matter collection container. Furthermore, the cleaning device of this embodiment may use two or more of the cleaning blades of this embodiment.

[0072] On the other hand, the process cartridge of this embodiment is not particularly limited as long as it is equipped with the cleaning device of this embodiment, which contacts the surface of one or more members to be cleaned, such as an image holder or an intermediate transfer body, and cleans the surface of the members to be cleaned. For example, it may include an image holder and the cleaning device of this embodiment for cleaning the surface of the image holder, and may be detachably attached to the image forming apparatus. For example, in a so-called tandem machine having image holders corresponding to each color of toner, the cleaning device of this embodiment may be provided for each image holder. In addition, cleaning brushes and the like may be used in combination with the cleaning device of this embodiment.

[0073] Furthermore, the image forming apparatus according to this embodiment is not particularly limited as long as it includes an image holder, a charging device for charging the image holder, an electrostatic latent image forming device for forming an electrostatic latent image on the surface of the charged image holder, a developing device for developing the electrostatic latent image formed on the surface of the image holder with toner to form a toner image, a transfer device for transferring the toner image formed on the surface of the image holder onto a recording medium, and a cleaning device of this embodiment for cleaning the surface of the image holder after the toner image has been transferred by the transfer device by bringing a cleaning blade into contact with it.

[0074] -Specific examples of image forming apparatus and cleaning apparatus- Next, specific examples of an image forming apparatus and a cleaning apparatus using the cleaning blade of this embodiment will be described in more detail with reference to the drawings. Figure 2 is a schematic diagram showing an example of an image forming apparatus according to this embodiment, and illustrates a so-called tandem type image forming apparatus. In Figure 2, 21 is the main housing, 22, 22a to 22d are the image-forming units, 23 is the belt module, 24 is the recording medium supply cassette, 25 is the recording medium transport path, 30 is each photoreceptor unit, 31 is the photoreceptor drum (an example of an image holder), 32 is the charging roll (an example of a charging device), 33 is each developing unit (an example of a developing device), 34 is the cleaning device (an example of a cleaning device), 35, 35a to 35d are the toner cartridges, 40 is the exposure unit (an example of an electrostatic latent image forming device), and 41 is the unit case. -42 represents the polygon mirror, 51 the primary transfer device, 52 the secondary transfer device, 53 the belt cleaning device, 61 the feed roll, 62 the transport roll, 63 the alignment roll, 66 the fixing device, 67 the discharge roll, 68 the paper discharge section, 71 the manual feed device, 72 the feed roll, 73 the double-sided recording unit, 74 the guide roll, 76 the transport path, 77 the transport roll, 230 the intermediate transfer belt, 231 and 232 the support rolls, 521 the secondary transfer roll, and 531 the cleaning blade. A unit comprising a primary transfer device, a secondary transfer device, and an intermediate transfer belt is an example of a transfer device.

[0075] The tandem image forming apparatus shown in Figure 2 has four image forming units 22 (specifically 22a to 22d) of four colors (yellow, magenta, cyan, and black in this embodiment) arranged within the main housing 21. Above these, a belt module 23 is provided, which includes an intermediate transfer belt 230 that circulates and transports along the direction of arrangement of each image forming unit 22. Below the main housing 21, a recording medium supply cassette 24 is provided, which contains a recording medium such as paper (not shown). A recording medium transport path 25, which serves as the transport path for the recording medium from the recording medium supply cassette 24, is arranged vertically.

[0076] In this embodiment, each image-forming unit 22 (22a to 22d) forms toner images in order from the upstream side in the circulation direction of the intermediate transfer belt 230, for example, for yellow, magenta, cyan, and black (the order is not necessarily limited to this order), and comprises each photoreceptor unit 30, each developing unit 33, and one common exposure unit 40. Here, the photoreceptor unit 30 is a sub-cartridge that integrates, for example, a photoreceptor drum 31, a charging device (charging roll) 32 for pre-charging the photoreceptor drum 31, and a cleaning device 34 for removing residual toner from the photoreceptor drum 31.

[0077] Furthermore, the developing unit 33 develops the electrostatic latent image formed by exposure in the exposure unit 40 on the charged photoreceptor drum 31 with the corresponding color toner (for example, negative polarity in this embodiment), and is integrated with a sub-cartridge consisting of, for example, the photoreceptor unit 30 to form a process cartridge (a so-called Customer Replaceable Unit). It goes without saying that the photoreceptor unit 30 may be separated from the developing unit 33 and used as a standalone process cartridge. Also, in Figure 2, reference numerals 35 (35a to 35d) are toner cartridges for supplying each color component toner to each developing unit 33 (the toner supply path is not shown).

[0078] On the other hand, the exposure unit 40 houses, for example, four semiconductor lasers (not shown), one polygon mirror 42, an imaging lens (not shown), and mirrors (not shown) corresponding to each photoreceptor unit 30 within a unit case 41. The light from the semiconductor lasers for each color component is deflected and scanned by the polygon mirror 42, and guided via the imaging lens and mirrors to the corresponding exposure point on the photoreceptor drum 31 to form an optical image.

[0079] In this embodiment, the belt module 23 is, for example, an intermediate transfer belt 230 stretched between a pair of support rolls (one of which is a drive roll) 231 and 232. A primary transfer device (primary transfer roll in this example) 51 is provided on the back surface of the intermediate transfer belt 230 corresponding to the photoreceptor drum 31 of each photoreceptor unit 30. By applying a voltage with the opposite polarity to the charging polarity of the toner to this primary transfer device 51, the toner image on the photoreceptor drum 31 is electrostatically transferred to the intermediate transfer belt 230. Furthermore, a secondary transfer device 52 is provided at the portion of the intermediate transfer belt 230 corresponding to the downstream support roll 232 of the downstream image-making unit 22d, and performs secondary transfer (bulk transfer) of the primary transfer image on the intermediate transfer belt 230 to a recording medium.

[0080] In this embodiment, the secondary transfer apparatus 52 includes a secondary transfer roll 521 that is pressed against the toner image holding surface side of the intermediate transfer belt 230, and a back roll (which also serves as a support roll 232 in this example) that is positioned on the back side of the intermediate transfer belt 230 and forms the opposing electrode of the secondary transfer roll 521. For example, the secondary transfer roll 521 is grounded, and a bias of the same polarity as the charging polarity of the toner is applied to the back roll (support roll 232). Furthermore, a belt cleaning device 53 is provided upstream of the uppermost imaging unit 22a of the intermediate transfer belt 230 to remove any residual toner on the intermediate transfer belt 230.

[0081] Furthermore, the recording medium supply cassette 24 is equipped with a feed roll 61 for feeding out the recording medium, and immediately behind this feed roll 61 is a transport roll 62 for feeding out the recording medium. Additionally, a registration roll (alignment roll) 63 is provided in the recording medium transport path 25 located immediately before the secondary transfer area to supply the recording medium to the secondary transfer area at a predetermined timing. On the other hand, a fixing device 66 is provided in the recording medium transport path 25 located downstream of the secondary transfer area, and a discharge roll 67 for discharging the recording medium is provided downstream of this fixing device 66, and the discharged recording medium is housed in a paper discharge section 68 formed in the upper part of the main body housing 21.

[0082] Furthermore, in this embodiment, a manual feed device (MSI) 71 is provided on the side of the main housing 21, and the recording medium on this manual feed device 71 is fed toward the recording medium transport path 25 by a feed roll 72 and a transport roll 62. Furthermore, the main housing 21 is also equipped with a double-sided recording unit 73. When the double-sided mode is selected to record images on both sides of the recording medium, the double-sided recording unit 73 reverses the discharge roll 67 and takes in the recording medium that has already been recorded on one side using the guide roll 74 just before the entrance. The transport roll 77 then transports the recording medium along the internal recording medium return transport path 76 and supplies it again to the alignment roll 63.

[0083] Next, we will describe in detail the cleaning device 34 located within the tandem-type image forming apparatus shown in Figure 2. Figure 3 is a schematic cross-sectional view showing an example of the cleaning apparatus of this embodiment, and shows the photoreceptor drum 31, charging roll 32, and developing unit 33, which are all integrated into a sub-cartridge, along with the cleaning apparatus 34 shown in Figure 2. In Figure 3, 32 represents a charging roll (an example of a charging device), 331 a unit case, 332 a developing roll, 333 a toner transport member, 334 a transport paddle, 335 a trimming member, 341 a cleaning case, 342 a cleaning blade, 344 a film seal, and 345 a transport member.

[0084] The cleaning device 34 has a cleaning case 341 that contains residual toner and has an opening facing the photoreceptor drum 31. A cleaning blade 342, which is positioned in contact with the photoreceptor drum 31, is attached to the lower edge of the opening of the cleaning case 341 via a bracket (not shown), while a film seal 344 is attached to the upper edge of the opening of the cleaning case 341 to maintain an airtight seal with the photoreceptor drum 31. Reference numeral 345 denotes a transport member that guides the waste toner contained in the cleaning case 341 to a waste toner container on the side.

[0085] In this embodiment, the cleaning blade of this embodiment is used as the cleaning blade 342 in all cleaning devices 34 of each imaging unit 22 (22a to 22d), and the cleaning blade 531 used in the belt cleaning device 53 may also be the cleaning blade of this embodiment.

[0086] Furthermore, the developing unit (developing device) 33 used in this embodiment has a unit case 331 that houses the developer and has an opening facing the photoreceptor drum 31, as shown in Figure 3, for example. Here, a developing roll 332 is arranged in the part of the unit case 331 facing the opening, and a toner transport member 333 for agitating and transporting the developer is arranged inside the unit case 331. In addition, a transport paddle 334 may be arranged between the developing roll 332 and the toner transport member 333. During development, after supplying developer to the developing roll 332, the developer layer thickness is controlled, for example by a trimming member 335, and then the roll is transported to the developing area facing the photoreceptor drum 31.

[0087] In this embodiment, the developing unit 33 uses, for example, a two-component developer consisting of toner and a carrier, but it is also acceptable to use a one-component developer consisting only of toner.

[0088] Next, the operation of the image forming apparatus according to this embodiment will be described. First, each image forming unit 22 (22a to 22d) forms a monochrome toner image corresponding to each color, and the monochrome toner images of each color are sequentially superimposed onto the surface of the intermediate transfer belt 230 in a manner that matches the original document information and are transferred in a primary transfer. Subsequently, the color toner images transferred to the surface of the intermediate transfer belt 230 are transferred to the surface of the recording medium by the secondary transfer device 52, and the recording medium on which the color toner images have been transferred undergoes a fixing process by the fixing device 66 before being discharged to the paper discharge unit 68. Meanwhile, in each imaging unit 22 (22a to 22d), residual toner on the photoreceptor drum 31 is cleaned by the cleaning device 34, and residual toner on the intermediate transfer belt 230 is cleaned by the belt cleaning device 53. During this imaging process, any remaining toner is cleaned by the cleaning device 34 (or belt cleaning device 53).

[0089] Furthermore, the cleaning blade 342 may be fixed via a spring rather than directly to the frame member within the cleaning device 34, as shown in Figure 3. [Examples]

[0090] The following describes embodiments of this disclosure, but this disclosure is not limited to these embodiments. In the following description, unless otherwise specified, "parts" and "%" all refer to mass.

[0091] <Example 1> Adipic acid (HOOC-C4H8-COOH) and 1,4-butanediol were polymerized in a 1:1 molar ratio, and the process was carried out to ensure that the terminal ends were -OH, thereby obtaining a polymerized polyester polyol (high molecular weight polyol) in which a linear diol (butanediol) with 4 carbon atoms was polymerized. The weight-average molecular weight of the obtained polyester polyol was 2000. The obtained polyester polyol was used as the soft segment component, and 1,4-butanediol (denoted as "1,4-BD", low molecular weight polyol, chain length extender), 4,4'-diphenylmethane diisocyanate (denoted as "MDI", polyisocyanate, manufactured by Nippon Polyurethane Industries Co., Ltd., Myrionate MT), and trimethylolpropane (denoted as "TMP", low molecular weight polyol, crosslinking agent, manufactured by Mitsubishi Gas Chemical Company, Inc.) were used as hard segment components. The amounts were adjusted according to the molar ratios shown in Table 1 below, and the mixtures were reacted at 80°C for 2 hours under a nitrogen atmosphere to prepare surface layer composition A1 and back layer composition A2, respectively.

[0092] Next, composition A2 for the back layer was poured into the center of the prepared centrifugal molding machine mold (mold temperature 100°C), and the mold temperature was immediately raised to 140°C. Ten minutes after the mold temperature reached 140°C, composition A1 for the surface layer was poured onto composition A2 for the back layer in the mold, and then cured for one hour while maintaining the mold temperature at 140°C. Subsequently, it was aged and heated at 110°C for 24 hours, cooled, and then cut to the specified dimensions to obtain a cleaning blade with a laminated structure of a surface layer and a back layer, measuring 16.8 mm × 348.5 mm × total thickness 2 mm.

[0093] <Examples 2-12, Comparative Examples 1-4> Composition A1 for the surface layer and composition A2 for the back layer were prepared by changing the types and molar ratios of high molecular weight polyols, low molecular weight polyols (chain length extender, crosslinking agent), and polyisocyanate according to the formulations shown in Table 1. Next, a cleaning blade was obtained in the same manner as in Example 1, except that the mold temperature after pouring back layer composition A2 into the center of the mold was adjusted to the temperature shown in Table 1.

[0094] <Measurement> Using the method described above, the 100% modulus and permanent elongation of each layer in the cleaning blade, as well as the Tc / Ts ratio in each region, were measured. The results are shown in Table 2. For the 100% modulus measurement, a Stroggraph AE elastomer manufactured by Toyo Seiki Co., Ltd. was used as the measuring device.

[0095] <Rating> (Measurement of wear amount) The cleaning blades obtained in each example were mounted on a Fujifilm Business Innovation DocuCentre-IV C5575. At this time, the NF (Normal Force) was set to 2.0 gf / mm and the W / A (Working Angle) to 11°. Under high temperature and high humidity conditions (28°C / 85%RH), 200,000 images with 100% image density were repeatedly formed using A4 paper (210 x 297 mm, Fujifilm Business Innovation P paper) without a transfer process. Then, under low temperature and low humidity conditions (10°C / 15%RH), 200,000 images with 30% halftone were printed on A4 paper (same as above), resulting in a total of 400,000 images formed. The amount of wear on the blade tip after image formation was observed by observing the cross-sectional profile using a Keyence VK-9500 laser microscope, and the cross-sectional area (μm²) of the worn part was measured. 2 The cross-sectional area (μm²) of the worn portion was measured. Here, the cross-sectional profile is that of the Y-axis-Z-axis cross-section of the cleaning blade in Figure 1. Based on the cross-sectional profile, the area of ​​the part that was chipped (disappeared) due to wear was determined and this was called the "cross-sectional area of ​​the worn portion (μm²)". 2 )” Blade wear (i.e., the cross-sectional area of ​​the worn part) is 3 μm. 2 If the following conditions are met, toner leakage will not occur, and the size is 3μm. 2 Slippage was observed beyond a certain point. The results are shown in Table 2.

[0096] (Evaluation of blade peeling) The cleaning blades obtained in each example were mounted on a Fujifilm Business Innovation DocuCentre III C3300 monochrome printer. The pressing force (NF) was set to 2.0 gf / mm and the working angle (W / A) to 10°. A test print (5% area per color) of an image was printed using A4 paper (210 x 297 mm, Fujifilm Business Innovation P paper). The area A at the blade edge was visually observed and evaluated according to the following criteria. The results are shown in Table 2. The evaluation results are categorized as follows: A is the best, and C is the worst. Furthermore, the closer the evaluation result is to A, the more effectively the cleaning blade is prevented from curling. • Evaluation criteria A: No blade peeling was observed even after exceeding 50,000 blades. B: Blade peeling was observed in between 30,000 and 50,000 blades. Blade peeling was observed before 30,000 blades were produced.

[0097] (Image evaluation) Using the same image forming apparatus as used for measuring wear, image formation with an image density of 1% (a solid image of 6.2 mm x 1 mm on an A4 size sheet of paper) was repeated 200,000 times on paper (C2r paper manufactured by Fujifilm Business Innovation). The deformation of the cleaning blade and the occurrence of color streaks (image quality defects) were then visually evaluated according to the following criteria. The results are shown in Table 2. • Evaluation criteria A: No color streaks were observed. B: Slight color streaks are visible in the image, but within acceptable limits. C: Color streaks are visible in the image, which is unacceptable.

[0098] [Table 1]

[0099] [Table 2]

[0100] From the above results, it can be seen that the cleaning blade of this embodiment suppresses edge peeling and wear compared to the cleaning blade of the comparative example, and produces images with reduced color streaks due to poor cleaning.

[0101] This embodiment includes the following aspects. (((1))) Having a laminated structure including a surface layer and a back layer, The surface layer and the back layer are made of polyurethane material. The 100% modulus of the aforementioned surface layer is 10 MPa or more and 20 MPa or less. A cleaning blade in which, when the thickness of the surface layer is Tc (mm) and the total thickness is [thickness of the surface layer + thickness of the back layer] Ts (mm), the region A from the end to 4.5% of the blade width satisfies the relationship 0.3 ≤ Tc / Ts ≤ 0.6, the central part B of the blade width satisfies the relationship 0.2 ≤ Tc / Ts ≤ 0.3, and the Tc / Ts of region A is greater than the Tc / Ts of the central part B.

[0102] (((2))) The cleaning blade described in (((1))) wherein the region A satisfies the relationship 0.45 ≤ Tc / Ts ≤ 0.55. (((3))) The cleaning blade described in (((1))) wherein the central portion B satisfies the relationship 0.225 ≤ Tc / Ts ≤ 0.275. (((4))) The cleaning blade according to (((1))), wherein the region A satisfies the relationship 0.45 ≤ Tc / Ts ≤ 0.55 and the central portion B satisfies the relationship 0.225 ≤ Tc / Ts ≤ 0.275.

[0103] (((5))) The cleaning blade according to (((1))), wherein the 100% modulus of the surface layer is 12.5 MPa or more and 17.5 MPa or less. (((6))) The cleaning blade according to (((1))), wherein the 100% modulus of the surface layer is 12.5 MPa or more and 17.5 MPa or less, the region A satisfies the relationship 0.45 ≤ Tc / Ts ≤ 0.55, and the central part B satisfies the relationship 0.225 ≤ Tc / Ts ≤ 0.275. (((7))) A cleaning blade according to any one of (((1))) to (((6))), wherein the permanent elongation of the surface layer is 4% or less. (((8))) The back layer is a cleaning blade according to any one of (((1))) to (((7))) whose 100% modulus is 4 MPa or more and 7 MPa or less, and whose permanent elongation is 2% or less.

[0104] A cleaning device equipped with a cleaning blade as described in any one of (((9))) (((1))) to (((8))). A process cartridge equipped with the cleaning device described in (((10))) (((9))) and which is detachable from the image forming apparatus. (((11))) Image holder and, A charging device for charging the image holder, An electrostatic latent image forming apparatus for forming an electrostatic latent image on the surface of the charged image holder, A developing apparatus that develops an electrostatic latent image formed on the surface of the image holder with toner to form a toner image, A transfer device for transferring a toner image formed on the surface of the image holder onto a recording medium, A cleaning device as described in (((9))) that cleans the surface of the image holder by bringing the cleaning blade into contact with the surface of the image holder, An image forming apparatus equipped with the following features.

[0105] The effects of the above embodiment are as follows: According to the invention of (((1))), a cleaning blade is provided that has a laminated structure including a surface layer and a back layer, wherein the surface layer and the back layer are made of polyurethane material, the 100% modulus of the surface layer is 10 MPa or more and 20 MPa or less, and when the thickness of the surface layer is Tc (mm) and the total thickness [thickness of the surface layer + thickness of the back layer] Ts (mm), the region A from the edge to 4.5% of the blade width satisfies the relationship 0.3 > Tc / Ts or Tc / Ts > 0.6, and the central part B of the blade width satisfies the relationship 0.2 ≤ Tc / Ts ≤ 0.3, thereby suppressing edge peeling and wear, and providing an image in which the occurrence of color streaks due to poor cleaning is suppressed.

[0106] According to the inventions of (((2))), (((4))), or (((6))), a cleaning blade is provided that can produce an image in which the occurrence of color streaks due to poor cleaning is suppressed compared to the case in which region A does not satisfy the relationship 0.45 ≤ Tc / Ts ≤ 0.55. According to the inventions of (((3))), (((4))), or (((6))), a cleaning blade is provided that suppresses wear and produces an image in which color streaks due to poor cleaning are suppressed, compared to the case where the central part B does not satisfy the relationship 0.225 ≤ Tc / Ts ≤ 0.275. According to the invention of (((5))), a cleaning blade is provided that suppresses edge peeling and wear, and suppresses the occurrence of color streaks due to poor cleaning, compared to cases where the 100% modulus of the surface layer is less than 12.5 MPa or greater than 17.5 MPa, and yields an image in which color streaks due to poor cleaning are suppressed.

[0107] According to the invention of (((7))), a cleaning blade is provided that can produce an image in which the occurrence of color streaks due to poor cleaning is suppressed compared to the case in which the permanent elongation of the surface layer is more than 4%. According to the invention of (((8))), a cleaning blade is provided that suppresses edge peeling and wear, and suppresses the occurrence of color streaks due to poor cleaning, compared to cases where the 100% modulus of the back layer is less than 4 MPa or greater than 7 MPa, and produces an image.

[0108] According to the inventions of (((9))), (((10))), or (((11))), a cleaning apparatus, process cartridge, or image forming apparatus is provided, which has a laminated structure including a surface layer and a back layer, wherein the surface layer and the back layer are made of polyurethane material, the 100% modulus of the surface layer is 10 MPa or more and 20 MPa or less, and when the thickness of the surface layer is Tc (mm) and the total thickness [thickness of the surface layer + thickness of the back layer] Ts (mm), the region A from the edge to 4.5% of the blade width satisfies the relationship 0.3 > Tc / Ts or Tc / Ts > 0.6, and the central part B of the blade width satisfies the relationship 0.2 ≤ Tc / Ts ≤ 0.3, thereby suppressing edge peeling and wear and providing an image in which the occurrence of color streaks due to poor cleaning is suppressed. [Explanation of symbols]

[0109] 10 Cleaning blade, 12 Front layer, 14 Back layer, 21 Main housing, 22, 22a to 22d Image-making unit, 23 Belt module, 24 Recording medium supply cassette, 25 Recording medium transport path, 30 Photoconductor unit, 31 Photoconductor drum (image holder), 32 Charging roll, 33 Developing unit, 34 Cleaning device, 35, 35a to 35d Toner cartridge, 40 Exposure unit, 41 Unit case, 42 Polygon mirror, 51 Primary transfer device, 52 Secondary transfer device, 53 Belt cleaning device, 61 Feed roll, 62 Transport roll, 63 Alignment roll, 66 Fixing device, 67 Discharge roll, 68 Paper discharge section, 71 Manual feed device, 72 Feed roll, 73 Duplex recording unit, 74 Guide roll, 76 Transport path, 77 Transport roll, 230 Intermediate transfer belt, 231, 232; support roll, 331; unit case, 332; developing roll, 333; toner transport component, 334; transport paddle, 335; trimming component, 341; cleaning case, 342; cleaning blade, 344; film seal, 345; transport component, 521; secondary transfer roll, 531; cleaning blade

Claims

1. It has a laminated structure including a surface layer and a back layer, The surface layer and the back layer are made of polyurethane material. The 100% modulus of the surface layer is 10 MPa or more and 20 MPa or less. A cleaning blade in which, when the thickness of the surface layer is Tc (mm) and the total thickness [thickness of the surface layer + thickness of the back layer] Ts (mm), the region A from the end to 4.5% of the blade width satisfies the relationship 0.3 ≤ Tc / Ts ≤ 0.6, the central part B of the blade width satisfies the relationship 0.2 ≤ Tc / Ts ≤ 0.3, and the Tc / Ts of region A is greater than the Tc / Ts of the central part B.

2. The cleaning blade according to claim 1, wherein the region A satisfies the relationship 0.45 ≤ Tc / Ts ≤ 0.

55.

3. The cleaning blade according to claim 1, wherein the central portion B satisfies the relationship 0.225 ≤ Tc / Ts ≤ 0.

275.

4. The cleaning blade according to claim 1, wherein the region A satisfies the relationship 0.45 ≤ Tc / Ts ≤ 0.55, and the central portion B satisfies the relationship 0.225 ≤ Tc / Ts ≤ 0.

275.

5. The cleaning blade according to claim 1, wherein the 100% modulus of the surface layer is 12.5 MPa or more and 17.5 MPa or less.

6. The cleaning blade according to claim 1, wherein the 100% modulus of the surface layer is 12.5 MPa or more and 17.5 MPa or less, the region A satisfies the relationship 0.45 ≤ Tc / Ts ≤ 0.55, and the central portion B satisfies the relationship 0.225 ≤ Tc / Ts ≤ 0.

275.

7. The cleaning blade according to claim 1, wherein the permanent elongation of the surface layer is 4% or less.

8. The cleaning blade according to claim 1, wherein the back layer has a 100% modulus of 4 MPa or more and 7 MPa or less, and a permanent elongation of 2% or less.

9. A cleaning device comprising a cleaning blade according to any one of claims 1 to 8.

10. A process cartridge comprising the cleaning device described in claim 9, which is detachable from an image forming apparatus.

11. Image holder and, A charging device for charging the image holder, An electrostatic latent image forming apparatus for forming an electrostatic latent image on the surface of the charged image holder, A developing apparatus that develops an electrostatic latent image formed on the surface of the image holder with toner to form a toner image, A transfer device for transferring a toner image formed on the surface of the image holder onto a recording medium, A cleaning device according to claim 9, wherein the cleaning blade is brought into contact with the surface of the image holder to clean the surface of the image holder, An image forming apparatus equipped with the following features.

Images