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

Abstract

To provide a cleaning blade excellent in wear resistance.SOLUTION: A cleaning blade in which a contact portion that comes into contact with a member to be cleaned is formed of a member that contains polyurethane rubber obtained by polymerizing at least a polyol component and a polyisocyanate component, has a ratio (EIT / Re) of an indentation elastic modulus (EIT [MPa]) to a rebound resilience (Re [%]) of 0.65 or more, has a rebound resilience (Re [%]) of less than 25%, and has a tensile stress at 23 °C and 200% strain of 15 [MPa] or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] 2. Description of the Related Art Conventionally, in electrophotographic copying machines, printers, facsimiles and the like, cleaning blades have been used as cleaning means for removing residual toner and the like from the surface of an image carrier such as a photoreceptor.

[0003] For example, Patent Document 1 discloses "a cleaning blade for an electrophotographic device having an elastic rubber member and a support member, the elastic rubber member having a two-layer structure consisting of an edge layer and a base layer, the edge layer being made of polyurethane having a JIS A hardness at 23°C of 65 to 72°, a rebound resilience of 37 to 60%, and a 200% modulus at 23°C of 3 to 8 MPa, and the base layer being made of polyurethane having a JIS A hardness at 23°C of 65 to 70° and a rebound resilience of 5 to 30%."

[0004] Furthermore, Patent Document 2 discloses a cleaning blade that is "made up of a blade member made of an elastic material, the blade tip being brought into contact with the surface of a member to be cleaned and removing deposits from the surface of the member to be cleaned as it moves over the surface, characterized in that the JIS Asker A hardness H35 at 35°C of the material that makes up the blade tip of the blade member and the resilience R35 at 35°C satisfy the relational expression (A): R35≦-1.56×H35+132."

[0005] Furthermore, Patent Document 3 discloses a cleaning blade in which "the contact portion that comes into contact with the member to be cleaned contains polyurethane rubber obtained by polymerizing at least a polyol component containing more than 50 mol % and not more than 75 mol % of 1,4-butanediol relative to the total polyol component, and a polyisocyanate component, and the ratio (M100 / Re) of the 100% modulus (M100 [MPa]) to the rebound resilience (Re [%]) is 0.25 or more, and the rebound resilience (Re [%]) is 25% or more." [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-109369 [Patent Document 2] Japanese Patent Publication No. 2020-016766 [Patent Document 3] Japanese Patent Publication No. 2020-181151 Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to provide a cleaning blade having a contact portion that contacts a member to be cleaned, which is made of a member containing polyurethane rubber obtained by polymerizing at least a polyol component and a polyisocyanate component, and which has excellent abrasion resistance compared to a member having a ratio (M100 / Re) of 100% modulus (M100 [Mpa]) to rebound elasticity (Re [%]) of less than 0.25, a member having a ratio (EIT / Re) of indentation elasticity (EIT [MPa]) to rebound elasticity (Re [%]) of less than 0.65, a member having a rebound elasticity (Re [%]) of 25% or more, and a member having a tensile stress of less than 15 [Mpa] at 200% strain at 23°C. The goal is to provide a ning blade. [Means for solving the problem]

[0008] The means for solving the problems include the following aspects.

[0009] <1> A cleaning blade whose contact portion that comes into contact with the member to be cleaned contains polyurethane rubber obtained by polymerizing at least a polyol component and a polyisocyanate component, and is composed of a member having a ratio (M100 / Re) of 100% modulus (M100 [Mpa]) to rebound elasticity (Re [%]) of 0.25 or more, a rebound elasticity (Re [%]) of less than 25%, and a tensile stress of 15 [Mpa] or more at 200% strain at 23°C. <2> The ratio (M100 / Re) of the 100% modulus (M100 [Mpa]) to the rebound resilience (Re [%]) is 0.28 or more and 1.0 or less. <1> The cleaning blade according to claim 1. <3> A cleaning blade whose contact portion that comes into contact with a member to be cleaned contains polyurethane rubber obtained by polymerizing at least a polyol component and a polyisocyanate component, and whose ratio (EIT / Re) of indentation modulus (EIT [MPa]) to rebound modulus (Re [%]) is 0.65 or more, whose rebound modulus (Re [%]) is less than 25%, and whose tensile stress at 200% strain at 23°C is 15 [MPa] or more. <4> The ratio (EIT / Re) of the indentation elastic modulus (EIT [MPa]) to the rebound elastic modulus (Re [%]) is 0.75 or more and 1.1 or less. <3> The cleaning blade according to claim 1. <5> The rebound resilience (Re [%]) is 10% or more and 22% or less, and the tensile stress at 200% strain at 23°C is 15 [Mpa] or more and 40 [Mpa] or less. <1> ~ <4> 10. The cleaning blade according to claim 9, <6> The polyol component contains 1,4-butanediol in an amount of more than 50 mol% and not more than 75 mol% based on the total polyol component. <1> ~ <5> 10. The cleaning blade according to claim 9, <7> The polyol component contains 1,4-butanediol in an amount of 55 mol % or more and 75 mol % or less based on the total polyol component. <6> The cleaning blade according to claim 1. <8> The polyol component contains 1,4-butanediol in an amount of 55 mol % to 60 mol % based on the total polyol component. <6> The cleaning blade according to claim 1. <9> The polymerization ratio of the polyisocyanate component is 5 mol % or more and 25 mol % or less with respect to the total polymerization components of the polyurethane rubber. <1> ~ <8> 10. The cleaning blade according to claim 9, <10> The polymerization ratio of the polyisocyanate component is 10 mol % or more and 20 mol % or less with respect to the total polymerization components of the polyurethane rubber. <9> The cleaning blade according to claim 1. <11> The crosslink density of the polyurethane rubber is 0.93×10 -3 mol / m 3 Over 1.45 x 10 -3 mol / m 3 is <1> ~ <10> 10. The cleaning blade according to claim 9, <12> The crosslink density of the polyurethane rubber is 1.01 × 10 -3 mol / m 3 Over 1.26 x 10 -3 mol / m 3 is <11> The cleaning blade according to claim 1. <13> The polyurethane rubber has hard segments and soft segments, and the average particle size of the hard segment aggregates is 1 μm or more and 10 μm or less. <1> ~ <12> 10. The cleaning blade according to claim 9, <14> The polyurethane rubber has hard segments and soft segments, and the average particle size of the hard segment aggregates is 1 μm or more and 5 μm or less. <13> The cleaning blade according to claim 1. <15> <1> ~ <14> A cleaning device comprising the cleaning blade according to any one of claims 1 to 4. <16> <15> A process cartridge comprising the cleaning device according to claim 1, which is detachable from an image forming apparatus. <17> an image carrier; a charging device that charges the image carrier; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the image carrier; a developing device that develops the electrostatic latent image formed on the surface of the image carrier with toner to form a toner image; a transfer device that transfers the toner image formed on the image carrier onto a recording medium; The cleaning blade is brought into contact with the surface of the image carrier after the toner image has been transferred by the transfer device to clean it. <15> a cleaning device according to An image forming apparatus comprising: [Effects of the Invention]

[0010] <1> According to the invention, a cleaning blade is provided in which the contact portion that comes into contact with the member to be cleaned is made of a member containing polyurethane rubber obtained by polymerizing at least a polyol component and a polyisocyanate component, and the cleaning blade has excellent wear resistance compared to a cleaning blade in which the ratio (M100 / Re) of the 100% modulus (M100 [Mpa]) to the rebound elasticity (Re [%]) of the member is less than 0.25, the rebound elasticity (Re [%]) of the member is 25% or more, and the tensile stress of the member at 200% strain at 23°C is less than 15 [Mpa]. <2> According to the invention, a cleaning blade having excellent wear resistance is provided, compared to a cleaning blade having a ratio (M100 / Re) of the 100% modulus (M100 [Mpa]) to the rebound resilience (Re [%]) of less than 0.28 or more than 1.0.

[0011] <3> According to the invention, a cleaning blade is provided in which the contact portion that comes into contact with the member to be cleaned is made of a member containing polyurethane rubber obtained by polymerizing at least a polyol component and a polyisocyanate component, and the cleaning blade has excellent wear resistance compared to a cleaning blade in which the ratio (EIT / Re) of the indentation modulus of elasticity (EIT [MPa]) to the rebound modulus of elasticity (Re [%]) of the member is less than 0.65, the rebound modulus of elasticity (Re [%]) of the member is 25% or more, and the tensile stress of the member at 200% strain at 23°C is less than 15 [MPa]. <4> According to the present invention, a cleaning blade having excellent wear resistance is provided, compared to a cleaning blade having a ratio (EIT / Re) of the indentation elastic modulus (EIT [MPa]) to the rebound elastic modulus (Re [%]) of less than 0.75 or more than 1.1.

[0012] <5> According to the invention relating to (1), a cleaning blade is provided which is superior in abrasion resistance compared to when the rebound resilience (Re [%]) is less than 10% or exceeds 22%, or when the tensile stress at 200% elongation at 23°C is less than 15 [Mpa] or exceeds 40 [Mpa].

[0013] <6> According to the invention, a cleaning blade having excellent wear resistance is provided, compared to when the polyol component contains 1,4-butanediol in an amount of 50 mol % or less or more than 75 mol % based on the total polyol component. <7> According to the invention, a cleaning blade having excellent wear resistance is provided compared to when the polyol component contains 1,4-butanediol in an amount of less than 55 mol % or more than 75 mol % based on the total polyol component. <8> According to the invention, a cleaning blade having excellent wear resistance is provided compared to when the polyol component contains 1,4-butanediol in an amount of less than 55 mol % or more than 60 mol % based on the total polyol component.

[0014] <9> According to the invention, a cleaning blade having excellent abrasion resistance is provided, compared to when the polymerization ratio of the polyisocyanate component is less than 5 mol % or more than 25 mol % relative to the total polymerization ratio of the polyurethane rubber. <10> According to the invention, a cleaning blade having excellent abrasion resistance is provided, compared to when the polymerization ratio of the polyisocyanate component is less than 10 mol % or more than 20 mol % relative to the total polymerization ratio of the polyurethane rubber.

[0015] <11> According to the invention, the crosslink density of the polyurethane rubber is 0.93×10 -3 mol / m 3 Less than or 1.45 x 10 -3 mol / m 3 This provides a cleaning blade with superior wear resistance compared to when the cleaning blade is greater than 100%. <12> According to the invention, the crosslink density of the polyurethane rubber is 1.01×10 -3 mol / m 3 Less than or 1.26 x 10 -3 mol / m 3 This provides a cleaning blade with superior wear resistance compared to when the cleaning blade is greater than 100%.

[0016] <13> According to the invention, a cleaning blade having excellent wear resistance is provided, compared to a cleaning blade having an average particle size of the hard segment aggregates of less than 1 μm or more than 10 μm. <14> According to the invention, a cleaning blade having excellent wear resistance is provided, compared to when the average particle size of the hard segment aggregates is less than 1 μm or exceeds 5 μm.

[0017] <15> , <16> or <17> According to the invention, the cleaning blade has a contact portion that comes into contact with the member to be cleaned, and is made of a member containing polyurethane rubber obtained by polymerizing at least a polyol component and a polyisocyanate component. In this cleaning device, a process cartridge, or an image forming apparatus is provided in which cleaning defects caused by wear of the cleaning blade are suppressed compared to a cleaning blade having a member in which the ratio (M100 / Re) of the 100% modulus (M100 [MPa]) to the rebound resilience (Re [%]) of the member is less than 0.25, the ratio (EIT / Re) of the indentation modulus (EIT [MPa]) to the rebound resilience (Re [%]) of the member is less than 0.65, the rebound resilience (Re [%]) of the member is 25% or more, and the tensile stress of the member at 200% strain at 23°C is less than 15 [MPa]. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2 is a schematic view illustrating an example of a cleaning blade according to the present embodiment. [Figure 2] FIG. 4 is a schematic view showing another example of a cleaning blade according to the present embodiment. [Figure 3] FIG. 4 is a schematic view showing another example of a cleaning blade according to the present embodiment. [Figure 4] 1 is a schematic diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. [Figure 5] FIG. 2 is a schematic cross-sectional view illustrating an example of a cleaning device according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described in detail.

[0020] <Cleaning blade> In the cleaning blade according to this embodiment, the contact portion that comes into contact with the member to be cleaned (hereinafter simply referred to as the "contact portion") is made of a material containing polyurethane rubber obtained by polymerizing at least a polyol component and a polyisocyanate component. The member constituting the contact portion satisfies at least one of the following characteristics (1) and (2). · Property (1): The ratio (M100 / Re) of the 100% modulus (M100 [Mpa]) to the rebound elasticity (Re [%]) is 0.25 or more, the rebound elasticity (Re [%]) is less than 25%, and the tensile stress at 200% strain at 23°C is 15 [Mpa] or more. Property (2): The ratio (EIT / Re) of the indentation modulus (EIT [MPa]) to the rebound modulus (Re [%]) is 0.65 or more, the rebound modulus (Re [%]) is less than 25%, and the tensile stress at 200% strain at 23°C is 15 [MPa] or more.

[0021] The cleaning blade according to this embodiment has excellent wear resistance due to the above-described configuration.

[0022] Here, cleaning blades used in image forming apparatuses and the like perform cleaning by sliding against the member to be cleaned (such as an image carrier), and therefore the contact portion with the member to be cleaned gradually wears out, causing cleaning defects.

[0023] Conventionally, cleaning blades have been known in which the contact portion that comes into contact with the member to be cleaned contains polyurethane rubber, and is made of a material in which the ratio (M100 / Re) of the 100% modulus (M100 [MPa]) to the rebound elasticity (Re [%]) is 0.25 or more, or the ratio (EIT / Re) of the indentation elasticity (EIT [MPa]) to the rebound elasticity (Re [%]) is 0.65 or more, and the rebound elasticity (Re [%]) is 25% or more (Patent Document 3, etc.).

[0024] Although this cleaning blade has high wear resistance, further improvement is desired. Therefore, the cleaning blade of this embodiment has a high ratio (M100 / Re) or a high ratio (EIT / Re) while lowering the rebound elasticity and increasing the tensile stress, thereby reducing the pressure fluctuation (i.e., maximum pressure) of the blade, improving the energy absorption capacity of the blade, and further stabilizing the behavior of the blade.

[0025] It is presumed that this improves the wear resistance of the cleaning blade according to this embodiment. The cleaning blade according to the present embodiment suppresses cleaning defects (e.g., image defects such as color streaks) caused by wear of the cleaning blade.

[0026] The M100 / Re ratio, EIT / Re ratio, rebound resilience, and tensile stress of a member containing polyurethane rubber are adjusted within the above ranges by selecting the type and amount of each polymerization component of the polyurethane rubber and the production conditions.

[0027] The configuration of the cleaning blade according to this embodiment will be described below.

[0028] The cleaning blade of this embodiment contains polyurethane rubber and satisfies the above characteristics. It is sufficient that the cleaning device has a contact member (hereinafter referred to as "contact member") at least in the area that comes into contact with the member to be cleaned. That is, it may have a two-layer structure with a first layer made of the contact member and in contact with the surface of the member to be cleaned, and a second layer as a backing layer provided on the back side of the first layer, or a three-layer or more structure. Also, it may have a structure in which only the corners of the part that comes into contact with the member to be cleaned are made of the contact member, and the surrounding area is made of another material.

[0029] Next, the configuration of the cleaning blade according to this embodiment will be described in more detail with reference to the drawings. Fig. 1 is a schematic diagram showing a cleaning blade according to a first embodiment, showing a state in which it is in contact with the surface of a member to be cleaned (for example, an image carrier). Fig. 2 is a diagram showing a cleaning blade according to a second embodiment, showing a state in which it is in contact with the surface of a member to be cleaned (for example, an image carrier). Fig. 3 is a diagram showing a cleaning blade according to a third embodiment, showing a state in which it is in contact with the surface of a member to be cleaned (for example, an image carrier).

[0030] First, each part of the cleaning blade will be described with reference to Fig. 1. As shown in Fig. 1, the cleaning blade has a contact part (contact angle part) 3A that comes into contact with a moving image carrier (photosensitive drum) 31 to clean the surface of the image carrier 31, a tip surface 3B where the contact angle part 3A forms one side and faces upstream in the direction of the drive (direction of arrow A), a ventral surface 3C where the contact angle part 3A forms one side and faces downstream in the direction of the drive (direction of arrow A), and a back surface 3D that shares one side with the tip surface 3B and faces the ventral surface 3C. In addition, the direction parallel to the contact angle portion 3A is called the depth direction, the direction from the contact angle portion 3A toward the side where the tip surface 3B is formed is called the thickness direction, and the direction from the contact angle portion 3A toward the side where the belly surface 3C is formed is called the width direction.

[0031] The cleaning blade 342A according to the first embodiment shown in FIG. 1 is entirely made of a single material, including the portion (contact angle portion) 3A that comes into contact with the photosensitive drum 31, i.e., it is an embodiment that consists of only a contact member.

[0032] The cleaning blade of this embodiment may have a two-layer structure, as in the second embodiment shown in Figure 2, including a portion (contact angle portion) 3A that contacts the photosensitive drum 31, and includes a first layer 3421B formed over the entire ventral surface 3C side and made of a contact member, and a second layer 3422B as a back layer formed on the back surface 3D side of the first layer and made of a material different from the contact member.

[0033] Furthermore, the cleaning blade of this embodiment may be configured to include, as in the third embodiment shown in Figure 3, a contact member (edge ​​member) 3421C made of a contact member, which includes a portion that contacts the photosensitive drum 31, i.e., a contact angle portion 3A, and has the shape of a cylinder cut into quarters and extending in the depth direction, with the right-angle portion of the shape forming the contact angle portion 3A, and a back member 3422C made of a material different from the contact member, which covers the back surface 3D side of the contact member 3421C in the thickness direction and the side opposite to the tip surface 3B in the width direction, i.e., which constitutes the portion other than the contact member 3421C. 3 shows an example of a contact member having a cylindrical shape cut into 1 / 4, but the contact member is not limited to this. The contact member may have, for example, a shape of an elliptical cylinder cut into 1 / 4, a square prism, a rectangular prism, etc.

[0034] In addition, the cleaning blade is usually used by being adhered to a rigid plate-like support material.

[0035] -Composition of contact materials- The contact member of the cleaning blade according to this embodiment contains polyurethane rubber. The contact member satisfies at least one of the above characteristics (1) and (2). There are.

[0036] Polyurethane rubber The polyurethane rubber is a polyurethane rubber obtained by polymerizing at least a polyol component and a polyisocyanate component. If necessary, the polyurethane rubber may be a polyurethane rubber obtained by polymerizing a resin having a functional group capable of reacting with an isocyanate group of the polyisocyanate in addition to the polyol component.

[0037] Polyol component The polyol component includes, for example, a high molecular weight polyol and a low molecular weight polyol.

[0038] The polymer polyol component is a polyol having a number average molecular weight of 500 or more (preferably 500 or more and 5000 or less). Examples of the polymer polyol component 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 with alkyl carbonates, polycaprolactone polyols, and polyether polyols. Commercially available polymer polyols include PLACCEL 205 and PLACCEL 240 manufactured by Daicel Chemical Industries, Ltd.

[0039] Here, the number average molecular weight is a value measured by gel permeation chromatography (GPC). The same applies hereinafter.

[0040] These polymer polyols may be used alone or in combination of two or more.

[0041] The polymerization ratio of the high molecular weight polyol component is preferably 30 mol % or more and 50 mol % or less, and more preferably 40 mol % or more and 50 mol % or less, based on the total polymerization components of the polyurethane rubber.

[0042] The low-molecular-weight polyol component is a polyol having a molecular weight (number average molecular weight) of less than 500. The low-molecular-weight polyol is a material that functions as a chain extender and a crosslinking agent.

[0043] A suitable example of the low-molecular-weight polyol component is 1,4-butanediol, which is present in an amount of more than 50 mol% and not more than 75 mol% (preferably 52 mol% to 75 mol%, more preferably 55 mol% to 75 mol%, and even more preferably 55 mol% to 60 mol%) of the total polyol components (high-molecular-weight polyol and low-molecular-weight polyol). When the proportion of 1,4-butanediol is within the above range, the abrasion resistance is improved. The proportion of 1,4-butanediol in all low-molecular-weight polyol components is preferably 80 mol % or more, more preferably 90 mol % or more, and even more preferably 100 mol %. In other words, it is most preferable to use 1,4-butanediol as all low-molecular-weight polyol components.

[0044] Examples of the low molecular weight polyol component include, in addition to 1,4-butanediol, diols (bifunctional), triols (trifunctional), and tetraols (tetrafunctional), which are well known as chain extenders and crosslinking agents. These polyols other than 1,4-butanediol may be used alone or in combination of two or more kinds.

[0045] The polymerization ratio of the low molecular weight polyol component is preferably more than 50 mol% and 75 mol% or less, more preferably 52 mol% or more and 75 mol% or less, more preferably 55 mol% or more and 75 mol% or less, and even more preferably 55 mol% or more and 60 mol% or less, based on the total polymerization components of the polyurethane rubber. .

[0046] Polyisocyanate component Examples of the polyisocyanate component 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] As the polyisocyanate component, 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), and hexamethylene diisocyanate (HDI) are more preferred.

[0048] These polyisocyanate components may be used alone or in combination of two or more.

[0049] The polymerization ratio of the polyisocyanate component is preferably 5 mol % or more and 25 mol % or less, and more preferably 10 mol % or more and 20 mol % or less, based on the total polymerization components of the polyurethane rubber. When the polymerization ratio of the polyisocyanate component is within the above range, the above properties (1) and (2) are more likely to be satisfied (particularly, the 100% modulus, indentation modulus, tensile stress, and elongation at break are more likely to be within the above ranges), and the abrasion resistance is further improved.

[0050] Resins with functional groups that can react with isocyanate groups The resin having a functional group capable of reacting with an isocyanate group (hereinafter referred to as "functional group-containing resin") is preferably a flexible resin, and from the viewpoint of flexibility, is more preferably an aliphatic resin having a linear structure. 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] Commercially available acrylic resins containing two or more hydroxyl groups include, for example, Actflow (grades: UMB-2005B, UMB-2005P, UMB-2005, UME-2005, etc.) manufactured by Soken Chemical & Engineering Co., Ltd.

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

[0053] The epoxy resin having two or more epoxy groups is preferably one that is not hard and brittle like conventional general epoxy resins, but is more flexible and tough than conventional epoxy resins. For example, in terms of molecular structure, the epoxy resin preferably has a structure (flexible skeleton) in its main chain structure that can increase the mobility of the main chain. Examples of flexible skeletons include alkylene skeletons, cycloalkane skeletons, and polyoxyalkylene skeletons, and polyoxyalkylene skeletons are particularly preferred. In terms of physical properties, epoxy resins with a lower viscosity relative to their molecular weight than conventional epoxy resins are preferred. Specifically, the weight-average molecular weight is preferably within the range of 900±100, and the viscosity at 25°C is preferably within the range of 15,000±5,000 mPa·s, and more preferably within the range of 15,000±3,000 mPa·s. Commercially available epoxy resins with these properties include, for example, EPLICON EXA-4850-150 manufactured by DIC.

[0054] The polymerization ratio of the functional group-containing resin is preferably set within a range that does not impair the effects of the cleaning blade according to this embodiment.

[0055] Crosslink density of polyurethane rubber The cross-linking density of polyurethane rubber is 0.93 x 10 -3 mol / m 3 Over 1.45 x 10 -3 mol / m 3 Less than or equal to 1.01 x 10 is preferable. -3 mol / m 3 Over 1.26 x 10 -3 mol / m 3 Less than or equal to 1.07 × 10 -3 mol / m 3 Over 1.22 x 10 -3 mol / m 3 The following is the result. When the crosslink density of the polyurethane rubber is within the above range, it becomes easier to satisfy the above properties (1) and (2) (particularly, the 100% modulus, indentation modulus, and tensile stress tend to fall within the above ranges), and the abrasion resistance is further improved.

[0056] The crosslink density of the polyurethane rubber is calculated by the following formula. Formula:n=E' / 3RT n; crosslinking density (mol / m 3 ) R: gas constant (8.31 J / K mol = N m / k mol = 10 7 dyne cm / k mol) T: Absolute temperature of parallel (storage) modulus of elasticity (k) E': Plateau storage modulus (dyne / cm 2 ) 1Pa=9.8(dyne / cm 2 )

[0057] The storage modulus is measured by the following method. The storage modulus is a property resulting from dynamic viscoelasticity. When a sinusoidal strain τ expressed as τ=τoeiωt is applied to a viscoelastic body in a steady vibrational manner, the stress σ is expressed as σ=σoei(ωt+δ). The dynamic elastic modulus at this time, that is, the complex If the elemental elastic modulus is E*, then it can be expressed as E*=σ / τ=σ0 / τ0·cosδ+i·σ0 / τ0·sinδ=E'+iE'', where E' is the storage modulus and E" is the loss modulus. Furthermore, the loss tangent is expressed as tanδ=E" / E', and these dynamic viscoelastic properties are measured using a dynamic viscoelasticity measuring instrument. The storage modulus is measured at 1 Hz using EXSTAR6000 (manufactured by SII Corporation).

[0058] Polyurethane rubber segment The polyurethane rubber preferably has hard segments and soft segments. The terms "hard segment" and "soft segment" refer to segments in which 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. Examples of materials constituting the hard segments (hard segment materials) include low-molecular-weight polyol components among polyol components, resins having functional groups capable of reacting with the isocyanate groups of polyisocyanates, etc. On the other hand, examples of materials constituting the soft segments (soft segment materials) include high-molecular-weight polyol components among polyol components.

[0059] Here, the average particle size of the hard segment aggregates is preferably 1 μm or more and 10 μm or less, and more preferably 1 μm or more and 5 μm or less. When the hard segment aggregates are within the above ranges, the above properties (1) and (2) are more easily satisfied (particularly, the 100% modulus, indentation modulus, and tensile stress are more easily satisfied within the above ranges), and the abrasion resistance is further improved.

[0060] The average particle size of the hard segment aggregates is measured as follows: Using a polarizing microscope (Olympus BX51-P), an image is taken at a magnification of 20x, and the image is binarized by image processing. The particle size (circle equivalent diameter) of the aggregates is measured at five points per cleaning blade (the particle size of five aggregates per point is measured), for 20 cleaning blades, for a total of 5 Calculate the average particle size from 00 pieces. The images were binarized using the image processing software OLYMPUS Stream essentials (Olympus Corporation), and the hue / saturation / brightness thresholds were adjusted so that the crystalline portion and hard segment aggregates were black and the amorphous portion (corresponding to the soft segment) was white.

[0061] Weight average molecular weight of polyurethane rubber The weight average molecular weight of the polyurethane rubber is preferably 1,000 or more and 4,000 or less, and more preferably 1,500 or more and 3,500 or less.

[0062] -Method of manufacturing polyurethane rubber The polyurethane rubber is produced by a general polyurethane production method such as a prepolymer method or a one-shot method. The prepolymer method is suitable for this embodiment because it can produce polyurethane with excellent abrasion resistance, but the production method is not limited thereto. The cleaning blade is produced by forming the cleaning blade composition prepared by the above method into a sheet using, for example, centrifugal molding or extrusion molding, and then cutting the sheet.

[0063] Examples of catalysts used in the production of polyurethane rubber include amine compounds such as tertiary amines, quaternary ammonium salts, and organometallic compounds such as organotin compounds. Examples of the tertiary amine include trialkylamines such as triethylamine, tetraalkyldiamines such as N,N,N',N'-tetramethyl-1,3-butanediamine, aminoalcohols such as dimethylethanolamine, ethoxylated amines, ethoxylated diamines, ester amines such as bis(diethylethanolamine) adipate, triethylenediamine (TEDA), cyclohexylamine derivatives such as 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.

[0064] 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.

[0065] Examples of organotin compounds include dialkyltin compounds such as dibutyltin dilaurate and dibutyltin di(2-ethylhexoate), stannous 2-ethylcaproate, and stannous oleate.

[0066] Among these catalysts, the tertiary ammonium salt triethylenediamine (TEDA) is used due to its hydrolysis resistance, while quaternary ammonium salts are preferred due to their 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 reactivity.

[0067] The content of the catalyst is preferably in the range of 0.0005% by mass to 0.03% by mass, and particularly preferably 0.001% by mass to 0.01% by mass, of the entire polyurethane rubber constituting the contact member. These may be used alone or in combination of two or more.

[0068] -Physical properties of contact materials- The M100 / Re ratio (ratio of 100% modulus (M100 [MPa]) to impact resilience (Re [%])) of the contact member is 0.25 or more, preferably 0.28 or more, and more preferably 0.3 or more. From the viewpoint of wear resistance, the upper limit of the M100 / Re ratio of the contact member is preferably 1.0 or less, and more preferably 0.9 or less. That is, the M100 / Re ratio of the contact member is preferably 0.28 or more and 1.0 or less, and more preferably 0.3 or more and 0.9 or less.

[0069] The EIT / Re ratio (ratio of indentation elastic modulus (EIT [MPa]) to rebound elastic modulus (Re [%])) of the contact member is 0.65 or more, preferably 0.75 or more, and more preferably 0.85 or more. From the viewpoint of wear resistance, the upper limit of the EIT / Re ratio of the contact member is preferably 1.1 or less, and more preferably 1.0 or less. That is, the EIT / Re ratio of the contact member is preferably 0.75 or more and 1.1 or less, and more preferably 0.85 or more and 1.0 or less.

[0070] The rebound resilience (Re [%]) of the contact member is less than 25%, preferably 22% or less, and more preferably 20% or less. The lower limit of the rebound resilience (Re [%]) of the contact member is preferably 10% or more, and more preferably 13% or more, from the viewpoints of suppressing blade squeal and wear resistance. That is, the modulus of resilience (Re [%]) of the contact member is preferably 10% or more and 22% or less, and more preferably 13% or more and 20% or less.

[0071] The 100% modulus (M100 [MPa]) of the contact member is preferably 4 MPa or more and 10 MPa or less, more preferably 5 MPa or more and 9 MPa or less, from the viewpoint of wear resistance.

[0072] The indentation elastic modulus (EIT [MPa]) of the contact member is preferably 10 MPa or more and 30 MPa or less, more preferably 15 MPa or more and 25 MPa or less, from the viewpoint of wear resistance.

[0073] The tensile stress of the contact member at 23°C and 200% strain is 15 MPa or more, but from the viewpoint of wear resistance, it is preferably 21 MPa or more, more preferably 26 MPa or more. From the viewpoint of wear resistance, the upper limit of the tensile stress of the contact member is preferably 40 MPa or less, more preferably 35 MPa or less. That is, the tensile stress of the contact member is preferably 21 [Mpa] or more and 40 [Mpa] or less, and more preferably 26 [Mpa] or more and 35 [Mpa] or less.

[0074] Here, the 100% modulus (M100 [MPa]), indentation modulus (EIT [MPa]), rebound modulus (Re [%]), and tensile stress are values ​​measured by the methods described in the Examples section below.

[0075] -Composition of non-contact components- Next, we will explain the composition of the non-contact member when the cleaning blade according to this embodiment is made of different materials for the contact member and the area other than the contact member (non-contact member), as in the second embodiment shown in Figure 2 and the third embodiment shown in Figure 3.

[0076] The non-contact member is not particularly limited and can be made of any known material as long as it has the function of supporting the contact member. Specific examples of materials used for the non-contact member include polyurethane rubber, silicone rubber, fluororubber, propylene rubber, and butadiene rubber. Among these, polyurethane rubber is preferred. Examples of polyurethane rubber include ester-based polyurethane and ether-based polyurethane, with ester-based polyurethane being particularly preferred.

[0077] -Manufacturing of cleaning blades- In the case of a cleaning blade consisting of only the contact member shown in FIG. 1, the cleaning blade is manufactured by the above-mentioned method for molding the contact member.

[0078] In the case of a cleaning blade having a multi-layer structure, such as the two-layer structure shown in Fig. 2, the cleaning blade is produced by bonding together a first layer as a contact member and a second layer as a non-contact member (or multiple layers in the case of a three- or more-layer structure). Suitable methods for bonding include double-sided tape and various adhesives. Alternatively, multiple layers may be bonded by pouring the materials for each layer into a mold at different times during molding and bonding the materials together without providing an adhesive layer.

[0079] In the case of a configuration having a contact member (edge ​​member) and a non-contact member (back member) as shown in FIG. 3, a first mold having a cavity (a region into which a contact member-forming composition is poured) corresponding to the shape of two contact members 3421C shown in FIG. 3 stacked together with their ventral surfaces 3C facing each other, and a second mold having a cavity corresponding to the shape of two contact members 3421C and two non-contact members 3422C stacked together with their ventral surfaces 3C facing each other are prepared. A contact member-forming composition is poured into the cavity of the first mold and cured to form a first molded product having two overlapping contact members 3421C. Next, after removing the first mold, a second mold is installed so that the first molded product is placed inside the cavity of the second mold. Thereafter, a non-contact member-forming composition is poured into the cavity of the second mold so as to cover the first molded product and cured to form a second molded product having two contact members 3421C and two non-contact members 3422C stacked together with their ventral surfaces 3C facing each other. Next, the formed second molded product is cut in the middle, i.e., at the part that will become the ventral surface 3C, so that the semi-cylindrical contact member is divided in the middle and cut into 1 / 4 of a cylindrical shape, and then further cut to specified dimensions to obtain the cleaning blade shown in Figure 3.

[0080] -Cleaning blade uses- When the cleaning blade according to the present embodiment is used to clean a member to be cleaned, the member to be cleaned is not particularly limited as long as it is a member in an image forming apparatus whose surface requires cleaning, and examples thereof include an intermediate transfer body, a charging roll, a transfer roll, a transfer material transport belt, a paper transport roll, a detoning roll that removes toner from a cleaning brush that removes toner from an image carrier, and the like, but in the present embodiment, an image carrier is particularly preferred. Note that the cleaning blade according to the present embodiment may also be used to clean a member other than a member for an image forming apparatus as the member to be cleaned.

[0081] (Cleaning device, process cartridge and image forming apparatus) Next, a cleaning device, a process cartridge, and an image forming apparatus using the cleaning blade of this embodiment will be described. The cleaning device of this embodiment is not particularly limited as long as it includes the cleaning blade of this embodiment as the cleaning blade that contacts the surface of the member to be cleaned and cleans the surface of the member to be cleaned. For example, the cleaning device may be configured such that the cleaning blade is fixed in a cleaning case having an opening on the side of the member to be cleaned, with the tip of the cleaning blade facing the opening, and the cleaning device includes a conveying member that guides foreign matter, such as waste toner, collected 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 include two or more cleaning blades of this embodiment.

[0082] When the cleaning blade of this embodiment is used to clean an image carrier, In order to suppress image deletion during image formation, the force NF (Normal Force) with which the cleaning blade is pressed against the image carrier is preferably in the range of 1.3 gf / mm or more and 2.3 gf / mm or less, and more preferably in the range of 1.6 gf / mm or more and 2.0 gf / mm or less. The length of the tip of the cleaning blade that bites into the image carrier is preferably in the range of 0.8 mm to 1.2 mm, and more preferably in the range of 0.9 mm to 1.1 mm. The angle W / A (Working Angle) at the contact point between the cleaning blade and the image carrier is preferably in the range of 8° to 14°, more preferably in the range of 10° to 12°.

[0083] 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 as a cleaning device that contacts the surface of one or more members to be cleaned, such as an image carrier or an intermediate transfer member, and cleans the surface of the member to be cleaned. For example, it may include an image carrier and a cleaning device of this embodiment that cleans the surface of this image carrier, and be detachable from the image forming apparatus. For example, in a so-called tandem machine having image carriers corresponding to toners of each color, a cleaning device of this embodiment may be provided for each image carrier. In addition, a cleaning brush or the like may be used in addition to the cleaning device of this embodiment.

[0084] Furthermore, the image forming apparatus according to this embodiment is not particularly limited as long as it includes an image carrier, a charging device that charges the image carrier, an electrostatic latent image forming device that forms an electrostatic latent image on the surface of the charged image carrier, a developing device that develops the electrostatic latent image formed on the surface of the image carrier with toner to form a toner image, a transfer device that transfers the toner image formed on the image carrier onto a recording medium, and a cleaning device according to this embodiment that cleans the surface of the image carrier by contacting the cleaning blade with the surface after the toner image has been transferred by the transfer device.

[0085] -Specific examples of image forming devices and cleaning devices- Next, specific examples of an image forming apparatus and a cleaning device using the cleaning blade of this embodiment will be described in more detail with reference to the drawings. FIG. 4 is a schematic diagram showing an example of the image forming apparatus of this embodiment, which is a so-called tandem type image forming apparatus. In FIG. 4, 21 denotes a main body housing, 22, 22a to 22d denote imaging units, 23 denotes a belt module, 24 denotes a recording medium supply cassette, 25 denotes a recording medium transport path, 30 denotes each photosensitive unit, 31 denotes a photosensitive drum, 33 denotes each developing unit, 34 denotes a cleaning device, 35, 35a to 35d denote toner cartridges, 40 denotes an exposure unit, 41 denotes a unit case, 42 denotes a polygon mirror, 51 denotes a primary transfer device, 52 denotes a secondary transfer device, 53 denotes a belt cleaning device, 61 denotes a feed roll, 62 denotes a transport roll, 63 denotes an alignment roll, 66 denotes a fixing device, 67 denotes a discharge roll, 68 denotes a paper discharge section, 71 denotes a manual feed device, 72 denotes a feed roll, 73 denotes a double-sided recording unit, 74 denotes a guide roll, 76 denotes a transport path, 77 denotes a transport roll, 230 denotes an intermediate transfer belt, 231 and 232 denote support rolls, 521 denotes a secondary transfer roll, and 531 denotes a cleaning blade.

[0086] The tandem image forming apparatus shown in FIG. 4 has imaging units 22 (specifically, 22a to 22d) of four colors (yellow, magenta, cyan, and black in this embodiment) arranged inside a main housing 21, and above them is arranged a belt module 23 including an intermediate transfer belt 230 that is circulated and transported along the arrangement direction of each imaging unit 22, while below the main housing 21 is arranged a recording medium supply cassette 24 that contains recording media (not shown) such as paper, and a recording medium transport path 25 that serves as a transport path for the recording media from this recording medium supply cassette 24 is arranged vertically.

[0087] In this embodiment, each image-forming unit 22 (22a to 22d) forms a toner image, for example, for yellow, magenta, cyan, or black (the arrangement is not necessarily in this order), in order from the upstream side in the circulation direction of the intermediate transfer belt 230, and is equipped with each photosensitive unit 30, each developing unit 33, and one common exposure unit 40. Here, the photosensitive unit 30 is a sub-cartridge that integrates, for example, a photosensitive drum 31, a charging device (charging roll) 32 that pre-charges the photosensitive drum 31, and a cleaning device 34 that removes residual toner from the photosensitive drum 31.

[0088] The developing unit 33 develops the electrostatic latent image formed by exposure on the charged photosensitive drum 31 by the exposure unit 40 with a corresponding color toner (negative polarity in this embodiment), and is integrated with a subcartridge consisting of the photosensitive unit 30 to form a process cartridge (a so-called customer replaceable unit). Of course, the photosensitive unit 30 may be separated from the developing unit 33 to form a standalone process cartridge. In Fig. 4, reference numeral 35 (35a to 35d) denotes a toner cartridge for replenishing each color component toner to each developing unit 33 (toner replenishing path is not shown).

[0089] On the other hand, the exposure unit 40 stores, within a unit case 41, for example, four semiconductor lasers (not shown), one polygon mirror 42, an imaging lens (not shown), and mirrors (not shown) corresponding to each photosensitive unit 30, and is arranged so that the light from the semiconductor laser for each color component is deflected and scanned by the polygon mirror 42, and the light image is directed to an exposure point on the corresponding photosensitive drum 31 via the imaging lens and mirror.

[0090] 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, 232, and a primary transfer device (in this example, a primary transfer roll) 51 is disposed on the back surface of the intermediate transfer belt 230 corresponding to the photosensitive drum 31 of each photosensitive unit 30, and a voltage of a polarity opposite to the charge polarity of the toner is applied to this primary transfer device 51, thereby electrostatically transferring the toner image on the photosensitive drum 31 to the intermediate transfer belt 230. Furthermore, a secondary transfer device 52 is disposed on the intermediate transfer belt 230 at a position corresponding to the support roll 232 on the downstream side of the most downstream image forming unit 22d, and performs secondary transfer (collective transfer) of the primary transfer image on the intermediate transfer belt 230 to a recording medium.

[0091] In this embodiment, the secondary transfer device 52 includes a secondary transfer roll 521 that is placed in pressure contact with the toner image bearing surface side of the intermediate transfer belt 230, and a back roll (which also serves as the support roll 232 in this example) that is placed on the back side of the intermediate transfer belt 230 and serves as an opposing electrode to 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 disposed upstream of the most upstream image forming unit 22 a of the intermediate transfer belt 230 to remove residual toner from the intermediate transfer belt 230 .

[0092] Further, the recording medium supply cassette 24 is provided with a delivery roll 61 that delivers the recording medium, and a transport roll 62 that delivers the recording medium is disposed immediately behind this delivery roll 61, and a registration roll (alignment roll) 63 that supplies the recording medium to the secondary transfer region at a predetermined timing is disposed in the recording medium transport path 25 located immediately before the secondary transfer region. Meanwhile, a fixing device 66 is provided in the recording medium transport path 25 located downstream of the secondary transfer region, and a discharge roll 67 for discharging the recording medium is provided downstream of this fixing device 66, and the discharged recording medium is stored in a paper discharge section 68 formed in the upper part of the main body housing 21.

[0093] Furthermore, in this embodiment, a manual sheet feeder (MSI) 71 is provided on the side of the main body housing 21, and the recording medium on this manual sheet feeder 71 is sent out toward the recording medium transport path 25 by a delivery roll 72 and a transport roll 62. Furthermore, a double-sided recording unit 73 is attached to the main body housing 21. When a double-sided mode is selected in which images are recorded on both sides of the recording medium, this double-sided recording unit 73 reverses the discharge roll 67 of the recording medium that has already been recorded on one side, takes it inside with a guide roll 74 just before the entrance, and transports the recording medium along the internal recording medium return transport path 76 with a transport roll 77, and supplies it again to the alignment roll 63 side.

[0094] Next, the cleaning device 34 disposed in the tandem image forming apparatus shown in FIG. 4 will be described in detail. FIG. 5 is a schematic cross-sectional view showing an example of the cleaning device of this embodiment, and also shows the photosensitive drum 31, charging roll 32, and developing unit 33, which are sub-cartridges, together with the cleaning device 34 shown in FIG. In FIG. 5, 32 denotes a charging roll (charging device), 331 denotes a unit case, 332 denotes a developing roll, 333 denotes a toner transport member, 334 denotes a transport paddle, 335 denotes a trimming member, 341 denotes a cleaning case, 342 denotes a cleaning blade, 344 denotes a film seal, and 345 denotes a transport member.

[0095] The cleaning device 34 has a cleaning case 341 that contains residual toner and has an opening facing the photosensitive drum 31. A cleaning blade 342 that is placed in contact with the photosensitive drum 31 is attached to the lower edge of the opening of this cleaning case 341 via a bracket (not shown), while a film seal 344 that maintains an airtight space between the cleaning case 341 and the photosensitive drum 31 is attached to the upper edge of the opening. Reference numeral 345 denotes a conveying member that guides the waste toner contained in the cleaning case 341 to a waste toner container on the side.

[0096] Next, the cleaning blade provided in the cleaning device 34 will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of a cleaning blade according to the present embodiment, and shows the cleaning blade 342 shown in FIG. 5 together with the photosensitive drum 31 that comes into contact with it.

[0097] 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.

[0098] 5, the developing unit (developing device) 33 used in this embodiment has a unit case 331 that contains a developer and has an opening facing the photosensitive drum 31. A developing roll 332 is disposed at a location facing the opening of the unit case 331, and a toner transport member 333 for stirring and transporting the developer is disposed within the unit case 331. Furthermore, a transport paddle 334 may be disposed between the developing roll 332 and the toner transport member 333. During development, the developer is supplied to the developing roll 332, and then the developer is transported to a development area facing the photosensitive drum 31 while the developer layer thickness is regulated by, for example, a trimming member 335.

[0099] In this embodiment, the developing unit 33 is a two-component developing unit made of, for example, toner and carrier. Although a component developer is used, a single component developer consisting of only toner may also be used.

[0100] Next, the operation of the image forming apparatus according to this embodiment will be described. First, each imaging unit 22 (22a to 22d) forms a monochromatic toner image corresponding to each color. The monochromatic toner images of each color are sequentially superimposed and primarily transferred onto the surface of intermediate transfer belt 230 so as to match the original document information. Next, the color toner images transferred onto the surface of intermediate transfer belt 230 are transferred onto the surface of a recording medium by secondary transfer device 52. The recording medium onto which the color toner images have been transferred is fixed by fixing device 66 and then discharged to paper discharge section 68. Meanwhile, in each of the image forming units 22 (22a to 22d), residual toner on the photosensitive 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 image forming process, the remaining toner is removed by the cleaning device 34 (or the belt cleaning device 53).

[0101] The cleaning blade 342 may be fixed via a spring member instead of being directly fixed to the frame member in the cleaning device 34 as shown in FIG. [Example]

[0102] The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In the following description, "parts" means "parts by mass."

[0103] <Examples 1 to 12 and Comparative Examples 1 to 3> The types and molar ratios of the high molecular weight polyol component, low molecular weight polyol component and isocyanate component, as well as the curing conditions, were changed according to Table 1 to prepare cleaning blades of various examples.

[0104] First, adipic acid (HOOC-C4H8-COOH) and 1,4-butanediol were polymerized in a 1:1 molar ratio, and the polymer was treated to have -OH groups at the ends to obtain a polyester polyol polymerized with a linear diol (butanediol) having four carbon atoms. The number-average molecular weight of the resulting polyester polyol was 3,000.

[0105] Next, in accordance with Table 1, a high molecular weight polyol component, a chain extender and a crosslinking agent as a low molecular weight polyol, and an isocyanate component were reacted in the amounts shown in Table 1 (molar ratio relative to the total polymer components) at 80°C for 2 hours under a nitrogen atmosphere to prepare a cleaning blade-forming composition A1. Next, the cleaning blade-forming composition A1 was poured into a centrifugal molding machine with a mold adjusted to 140°C, and cured under the curing and maturation conditions shown in Table 1, followed by maturation heating. The cooled cured product was then cut to obtain a cleaning blade having a width of 8 mm and a thickness of 2 mm.

[0106] The hardening maturity conditions A to E shown in Table 1 are as follows. Curing condition A: After 1 hour of curing reaction at 100℃, heat at 110℃ for 24 hours. Curing condition B: After 1 hour of curing reaction at 110℃, heat for 24 hours at 110℃. Curing condition C: After 2 hours of curing reaction at 110°C, heat for 48 hours at 110°C. Curing condition D: After 40 minutes of curing reaction at 100°C, heat at 110°C for 24 hours. Curing condition E: After 40 minutes of curing reaction at 100°C, heat for 24 hours at 100°C

[0107] <Evaluation> The physical properties of the contact portion of the cleaning blade obtained in each example were measured as follows, and the results are shown in Table 1.

[0108] (Physical properties of contact area) -100% Modulus (M100)- 100% Modulus: The 100% modulus was determined from the stress at 100% strain using a dumbbell-shaped No. 3 test piece, measured at a temperature of 23°C and a tensile speed of 500 mm / min, in accordance with JIS K6251 (2010). The measuring device used was a Strograph AE Elastomer manufactured by Toyo Seiki Co., Ltd.

[0109] - Elastic Indentation Modulus (EIT) - The indentation elastic modulus (EIT) was measured in accordance with ISO14577 (2002) from the slope of the unloading curve obtained during unloading from the load-penetration curve of the indenter in the load range of 65% to 95% of the maximum load. The measurement conditions were as follows: Measuring equipment: Nanoindentation method dynamic ultra-microhardness tester "Product name PICODENTOR HM500 (manufactured by Fisher Instruments)" Indenter: Berkovich-type conical diamond indenter with a 120° face angle Indenter depth: 20 μm Indenter pressing speed: 12.5 μm / sec Indenter unloading speed: 12.5 m / s ·Temperature: 23℃

[0110] -Rebound resilience (Re)- The rebound resilience was determined in accordance with JIS K6255 (1996) using a Lupke rebound resilience tester in a 23°C environment.

[0111] -Tensile stress- The tensile stress was measured using a Strograph AE Elastomer manufactured by Toyo Seiki Co., Ltd., and the stress at 200% strain was defined as the tensile stress. The measurement conditions were as follows: Sample: Dumbbell-shaped No. 3 test piece Pulling speed: 500mm / min ·Temperature: 23℃

[0112] -Average particle size of hard segment aggregates (average particle size of HS aggregates)- The average particle size of the hard segment aggregates was measured according to the method described above.

[0113] -Crosslink density of urethane rubber (crosslink density of rubber)- The crosslink density of the urethane rubber was measured according to the method already described.

[0114] (evaluation) The cleaning blade obtained in each example was mounted on a "DocuCentre-IV C5575" manufactured by Fujifilm Business Innovation Co., Ltd., and the NF (Normal Force) was set to 2.0 gf / mm and the W / A (Working Angle) to 11°.

[0115] -Blade wear resistance- The resulting image forming device was used to print 20,000 sheets at high temperature and high humidity (28°C / 85%RH), and then 20,000 sheets in a low temperature and low humidity environment (10°C / 15%), for a total of 40,000 prints. The amount of wear at the blade tip was measured by observing the cross-sectional profile using a Keyence VK-9500 laser microscope and measuring the cross-sectional area of ​​the worn area.

[0116] -Cleaning ability- Furthermore, using the obtained image forming apparatus, an image was printed with an image density of 1% (6.2 mm on A4 size paper). The image formation was repeated 2,000 times on paper (C2r paper, manufactured by Fujifilm Business Innovation Co., Ltd.) with a 1000×1mm solid image. After that, the occurrence of image quality defects such as color streaks was visually evaluated according to the following criteria. A: No color streaks are observed B: Slight color streaks are visible in the image, but within the acceptable range. C: Color streaks are observed in the image and are unacceptable.

[0117] The abbreviations in Table 1 are as follows: -High molecular weight polyol component- PEPO: Polyester polyol (number average molecular weight = 3000) PTMG: Polytetramethylene ether glycol (number average molecular weight = 2000) -Low molecular weight polyol component (chain extender)- 1.4BD: 1,4-butanediol -Low molecular weight polyol component (crosslinking agent)- TMP: Trimethylolpropane (TMP, manufactured by Mitsubishi Gas Chemical Company, Inc.) -Polyisocyanate component- MDI: 4,4'-diphenylmethane diisocyanate (Millionate MT, manufactured by Nippon Polyurethane Industry Co., Ltd.)

[0118] [Table 1-1]

[0119] [Table 1-2]

[0120] The above results show that the cleaning blade of this example has higher wear resistance than the cleaning blade of the comparative example, and therefore the cleaning blade of this example also suppresses image defects caused by cleaning blade wear compared to the cleaning blade of the comparative example. [Explanation of symbols]

[0121] 21 main body housing, 22, 22a to 22d imaging units, 23 belt module, 24 recording medium supply cassette, 25 recording medium transport path, 30 photosensitive unit, 31 Photosensitive drum (image carrier), 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 double-sided 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 member, 334 transport paddle, 335 trimming member, 341 cleaning case, 342, 342A, 342B, 342C Cleaning blade, 344 film seal, 345 conveying member, 521 secondary transfer roll, 531 cleaning blade, 3421B first layer, 3422B second layer, 3421C contact member, 3422C back member

Claims

1. A cleaning blade is constructed of a member whose contact portion that comes into contact with a member to be cleaned contains polyurethane rubber obtained by polymerizing at least a polyol component and a polyisocyanate component, and whose ratio (EIT / Re) of indentation modulus (EIT [MPa]) to rebound modulus (Re [%]) is 0.65 or more, whose rebound modulus (Re [%]) is less than 25%, and whose tensile stress at 200% strain at 23°C is 15 [MPa] or more.

2. 2. The cleaning blade according to claim 1, wherein the ratio (EIT / Re) of the indentation elastic modulus (EIT [MPa]) to the rebound elastic modulus (Re [%]) is 0.75 or more and 1.1 or less.

3. 3. The cleaning blade according to claim 1, wherein the rebound resilience (Re [%]) is 10% or more and 22% or less, and the tensile stress at 200% strain at 23°C is 15 [MPa] or more and 40 [MPa] or less.

4. 4. The cleaning blade according to claim 1, wherein the polyol component contains 1,4-butanediol in an amount of more than 50 mol % and not more than 75 mol % based on the total amount of the polyol component.

5. 5. The cleaning blade according to claim 4, wherein the polyol component contains 1,4-butanediol in an amount of 55 mol % to 75 mol % based on the total amount of the polyol component.

6. 5. The cleaning blade according to claim 4, wherein the polyol component contains 1,4-butanediol in an amount of 55 mol % to 60 mol % based on the total amount of the polyol component.

7. 7. The cleaning blade according to claim 1, wherein the polymerization ratio of the polyisocyanate component is 5 mol % or more and 25 mol % or less with respect to all polymerization components of the polyurethane rubber.

8. 8. The cleaning blade according to claim 7, wherein the polymerization ratio of the polyisocyanate component is 10 mol % or more and 20 mol % or less with respect to the total polymerization ratio of the polyurethane rubber.

9. The crosslink density of the polyurethane rubber is 0.93×10 －３ mol / m ３ The above is 1.45 x 10 －３ mol / m ３ The cleaning blade according to any one of claims 1 to 8, wherein:

10. The crosslink density of the polyurethane rubber is 1.01 × 10 －３ mol / m ３ 1.26 x 10 －３ mol / m ３ 10. The cleaning blade according to claim 9, wherein:

11. The polyurethane rubber has a hard segment and a soft segment, 11. The cleaning blade according to claim 1, wherein the average particle size of the aggregate of the segments is 1 μm or more and 10 μm or less.

12. 12. The cleaning blade according to claim 11, wherein the polyurethane rubber has a hard segment and a soft segment, and the average particle size of the hard segment aggregates is 1 μm or more and 5 μm or less.

13. A cleaning device comprising the cleaning blade according to any one of claims 1 to 12.

14. A process cartridge comprising the cleaning device according to claim 13, and being detachable from an image forming apparatus.

15. an image carrier; a charging device that charges the image carrier; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the image carrier; a developing device that develops the electrostatic latent image formed on the surface of the image carrier with toner to form a toner image; a transfer device that transfers the toner image formed on the image carrier onto a recording medium; the cleaning device according to claim 13, wherein the cleaning blade is brought into contact with the surface of the image carrier after the toner image has been transferred by the transfer device to clean the surface; An image forming apparatus comprising:

Images