Cleaning blade, process cartridge, and image formation apparatus

Abstract

To provide a cleaning blade that can suppress an increase in torque even immediately after the start of use of an image formation apparatus and can achieve good cleaning performance even when high-density images are continuously printed.SOLUTION: There is provided a cleaning blade that comes into contact with a surface of a member to be cleaned to remove residues on the surface of the member to be cleaned. The cleaning blade includes a cleaning blade base having an elastic member and a cleaning blade support member that supports the cleaning blade base. The elastic member has a coating layer provided on a tip portion that comes into contact with the member to be cleaned. In the coating layer on a lower surface of the cleaning blade base, an average value of a luminance histogram obtained from a luminance image acquired by a confocal laser microscope at a position separated by a distance of 100 [μm] to the inner side from a tip ridge line portion is 15,000 or greater and 25,000 or less.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Conventionally, in electrophotographic image forming apparatuses, residual toner adhering to the surface of an image carrier (sometimes called a member to be cleaned) after a toner image is transferred to a recording medium or an intermediate transfer member in an image forming process is removed by a cleaning means.

[0003] A cleaning blade is typically used as the cleaning means because of its simple structure and excellent cleaning performance. The cleaning blade typically comprises an elastic member made of polyurethane rubber or the like and a support member. The base end of the elastic member is supported by the support member, and the contact portion (tip ridge portion) of the elastic member is pressed against the image carrier surface to intercept, scrape, and remove toner remaining on the image carrier surface. In cleaning means using a cleaning blade, the contact between the cleaning blade and the image carrier generates friction between the cleaning blade and the image carrier, increasing the torque required to rotate the image carrier and potentially causing the image carrier to stop. Furthermore, friction between the cleaning blade and the image carrier can wear the contact portion, causing it to turn over, which can allow toner to slip through the turned-over portion, resulting in poor cleaning performance.

[0004] For example, in recent years, in the case of the cleaning blade, a cleaning blade coated with a lubricant containing a fluorine-based compound has been used for the purpose of reducing the frictional force with the image carrier, and a cleaning blade in which the fluorine-based compound contained in the lubricant is vinylidene fluoride has been proposed (see Patent Documents 1 to 5). Furthermore, in order to impart appropriate flexibility and hardness to the elastic member in the cleaning blade and to prevent the edge of the cleaning blade from turning over or being worn down, it has been proposed that the Martens hardness of the surface at a position 20 μm inward from the edge of the elastic member be 1.0 N / mm 2 ]~15.0[N / mm 2 (See Patent Document 6.) Furthermore, in order to improve the sliding properties of the cleaning blade, a cleaning blade coated with a dispersion liquid in which PMMA (polymethacrylic acid) particles are dispersed in a fluorine-based solvent has been proposed (See Patent Document 7.) Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide a cleaning blade that can suppress an increase in torque even immediately after starting use of an image forming apparatus, and that can provide good cleaning performance even when continuously printing high-density images such as full solid images. [Means for solving the problem]

[0006] The cleaning blade of the present invention, as a means for solving the above-mentioned problems, is a cleaning blade that contacts the surface of a member to be cleaned to remove residues on the surface of the member to be cleaned, and is characterized in that the cleaning blade comprises a cleaning blade substrate having an elastic member and a cleaning blade support member that supports the cleaning blade substrate, the elastic member having a coating layer provided on the tip portion that contacts the member to be cleaned, and the coating layer on the underside of the cleaning blade substrate has an average brightness histogram value of 15,000 or more and 25,000 or less at a position 100 μm inward from the tip ridge portion. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a cleaning blade that can suppress an increase in torque even immediately after starting use of an image forming apparatus, and that can provide good cleaning performance even when continuously printing high-density images such as full solid images. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a state in which a cleaning blade is in contact with the surface of an image bearing member. [Figure 2] FIG. 2 is a perspective view showing an example of the cleaning blade for an image carrier of the present invention. [Figure 3] FIG. 3 is a schematic cross-sectional view showing another example of the cleaning blade for an image carrier of the present invention. [Figure 4] FIG. 4 is a schematic cross-sectional view showing an example of the image forming apparatus of the present invention. [Figure 5] FIG. 5 is a schematic cross-sectional view showing an example of an imaging unit in the image forming apparatus of FIG. [Figure 6] FIG. 6 is a schematic diagram showing the method for forming the coating layer carried out in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the following, as one embodiment of the present invention, a cleaning blade 62 is described, which is composed of a cleaning blade support member 621 and a cleaning blade substrate 622, and the cleaning blade substrate 622 has an elastic edge layer 622a and a base layer 622b, an abutting portion 62c, and a covering layer 623 on at least a portion including the abutting edge of the abutting portion 62c. In the following, the cleaning blade of the present invention will be described in the case where an image bearing member is used as a member to be cleaned. Hereinafter, the "blade substrate in the cleaning blade" may be referred to as the "blade substrate."

[0010] [Cleaning blade] One embodiment of the cleaning blade of the present invention is a cleaning blade that contacts the surface of a member to be cleaned to remove residues on the surface of the member to be cleaned, the cleaning blade has a cleaning blade substrate having an elastic member and a cleaning blade support member that supports the cleaning blade substrate; the elastic member has a coating layer provided on a tip portion that contacts the member to be cleaned, In the coating layer on the lower surface of the cleaning blade substrate, the average value of a luminance histogram at a position 100 μm inward from the tip ridge line is 15,000 or more and 25,000 or less, and other members may be further included as necessary. The cleaning blade of the present invention is a cleaning blade that removes residues adhering to the image bearing member by contacting the surface of the image bearing member.

[0011] The residue is not particularly limited as long as it is attached to the surface of the image bearing member and is a target for removal by the cleaning blade, and examples thereof include toner, lubricant, inorganic fine particles, organic fine particles, paper powder, dirt, dust, and mixtures thereof.

[0012] In conventional cleaning means using a cleaning blade, friction occurs when the cleaning blade comes into contact with the image carrier, increasing the torque required to rotate the image carrier, which causes the image carrier to stop rotating. Furthermore, the friction causes wear at the contact portion of the cleaning blade with the image carrier, which can cause the cleaning blade to turn over or allow toner to slip through, resulting in poor cleaning performance.

[0013] To improve the sliding properties of the cleaning blade and prevent blade curling and torque increase, a process known as touch-up is widely used in which a lubricant, such as a metal soap such as zinc stearate or PMMA (polymethacrylic acid) particles, is applied to the tip of the cleaning blade. Typically, as an image forming apparatus operates, toner gradually accumulates between the cleaning blade and the image carrier, and the toner functions as a lubricant. Therefore, the lubricant only needs to exhibit lubricating properties for the short period between the start of operation of the image forming apparatus and the stabilization of the cleaning blade's behavior. However, the fine particles contained in conventional lubricants have a problem in that they have weak adhesion to the substrate and detach from the cleaning blade before the cleaning blade's behavior stabilizes.

[0014] A known technique involves applying a lubricant consisting of fine particles and a binder component that fixes the fine particles to the contact area of ​​the cleaning blade with the image carrier, with the aim of preventing the fine particles from detaching from the cleaning blade. The binder component makes it difficult for the fine particles to detach from the cleaning blade, which is effective in preventing an increase in torque. However, the lubricant tends to remain on the cleaning blade, making it difficult for the tip of the cleaning blade to be exposed, reducing the pressure applied to the contact area with the image carrier and deteriorating cleaning performance. This is particularly noticeable when a large amount of toner penetrates the nip between the cleaning blade and the image carrier, as in the case of continuous printing of a full solid image.

[0015] As a result of extensive research, the inventors have found that by making the coating layer made of the lubricant brittle, the coating layer at the tip of the cleaning blade becomes more easily scraped off while still preventing torque increase, causing the tip of the blade to become exposed early and increasing the pressure applied to the contact point with the image carrier, making it possible to maintain cleaning performance even when a large amount of toner penetrates into the nip between the cleaning blade and the image carrier, such as in continuous printing of an all-solid image, and thus making it possible to achieve both prevention of torque increase and cleaning performance.

[0016] Therefore, in the present invention, a cleaning blade for cleaning an image carrier has an edge layer and a coating layer, and the average value of the brightness histogram at a position on the underside of the blade that is 100 μm away from the tip ridge is 15,000 or more and 25,000 or less. This makes it possible to suppress an increase in torque even immediately after starting to use the image forming apparatus, and to obtain a cleaning blade that exhibits good cleaning properties even when a large amount of toner enters the nip portion with the image carrier, such as when continuously printing a full solid image.

[0017] <Coating layer> The coating layer contains fine particles and a binding component incompatible with the fine particles, and further contains other components as necessary. The coating layer refers to a layer provided on one end portion of the peripheral surface of the blade substrate, which will be described later and which serves as the tip of the cleaning blade. The coating layer may be formed on at least a portion of the blade substrate, including the abutment edge where the cleaning blade and the image carrier abut, or may be formed on the entire abutment edge, or may be formed on the entire surface of the blade substrate. Among these, it is preferable that the coating layer be formed on the entire abutment edge. The surface region of the blade substrate on which the coating layer is not provided is sometimes referred to as the uncoated region.

[0018] The average thickness of the coating layer of the cleaning blade is preferably 0.5 μm or more and 10 μm or less. When the average thickness of the coating layer is 0.5 μm or more, a sufficient sliding effect can be obtained, and when the average thickness of the coating layer is 10 μm or less, the coating layer becomes brittle, thereby maintaining cleaning performance. The average thickness of the coating layer can be the average value of thicknesses [μm] measured at three or more locations on the coating layer. Examples of locations for measuring the average thickness of the coating layer include a position 100 μm inward from the edge and the center of the coating layer.

[0019] The average thickness of the coating layer can be measured by scraping off a portion of the coating layer with a spatula or cotton swab, and measuring the shape using a three-dimensional measuring device such as a contact surface roughness meter (Surftest SJ-500, manufactured by Mitutoyo) or a laser microscope (LEXT OLS4100, manufactured by Olympus).

[0020] Here, one embodiment and other embodiments of the cleaning blade of the present invention will be described with reference to the drawings. However, the uses of the cleaning blade of the present invention are not limited to these embodiments. In each drawing, the same components are given the same reference numerals, and duplicated explanations may be omitted. Furthermore, the number, position, shape, etc. of the following components are not limited to this embodiment, and may be any number, position, shape, etc. that is preferable for implementing the present invention.

[0021] FIG. 1 is a schematic cross-sectional view showing one embodiment of the cleaning blade of the present invention, and FIG. 2 shows the cleaning blade in contact with the surface of an image carrier. FIG. 3 is a perspective view of the cleaning blade shown in FIG. 1 and an enlarged view of the vicinity of the contact portion. Cleaning blade 62 is composed of a flat cleaning blade support member 621 made of a rigid material such as metal or hard plastic, and a flat cleaning blade substrate 622 connected at one end to cleaning blade support member 621 and having a predetermined free end at the other end. Cleaning blade substrate 622 is fixed to one end of cleaning blade support member 621 with an adhesive or the like, and the other end of cleaning blade support member 621 is cantilevered and supported by the case of the cleaning device. The cleaning blade substrate 622 has a cleaning blade tip surface 62a, a cleaning blade lower surface 62b, a cleaning blade abutment portion 62c which is one end on the free end side of the cleaning blade substrate 622, and a cleaning blade side surface 62d, and has a coating layer 623 on at least a part including the abutting side of the cleaning blade abutment portion 62c. The cleaning blade 62 is arranged so that the cleaning blade abutment portion 62c abuts against the surface of the photoreceptor 3 along the longitudinal direction. As shown in FIG. 1, the cleaning blade lower surface 62b is the surface of the cleaning blade substrate 622 on which the cleaning blade support member 621 is not provided.

[0022] 4 is a schematic cross-sectional view showing another embodiment of the cleaning blade of the present invention. Cleaning blade 62 is composed of a cleaning blade support member 621 and a cleaning blade substrate 622. The cleaning blade substrate 622 has an elastic edge layer 622a, a base layer 622b, a contact portion 62c, and a covering layer 623 on at least a portion of the contact portion 62c, including the contact side. Note that the cleaning blade tip surface 62a, cleaning blade lower surface 62b, and cleaning blade side surface 62d are omitted from the illustration.

[0023] The coating layer in the present invention is composed of particles and a resin binder component. In one aspect of the present invention, the particles are preferably domains in the sea-island structure of the coating layer. The type and amount of particles added are preferably selected depending on the type of resin binder component so that the particles form domains.

[0024] The shape of the particles is not particularly limited and can be appropriately selected depending on the purpose, and may be regular or irregular. Among these, regular shapes are preferred. When the shape of the domain is regular, it is preferably spherical. Such a shape is preferable because it can prevent problems such as damage to an image carrier or a blade substrate in a cleaning blade caused by particles detached from the coating layer.

[0025] The volume-average particle size (50% volume diameter, median diameter) of the particles is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.1 μm to 1 μm, more preferably 0.1 μm to 0.5 μm, and even more preferably 0.1 μm to 0.3 μm. If the volume-average particle size of the particles is 1 μm or less, the particles tend to settle in the solvent, making it difficult to stably disperse them. Furthermore, if the volume-average particle size of the particles is 0.5 μm or less, they can be more stably dispersed in a non-aqueous solvent.

[0026] The method for measuring the volume-average particle diameter (50% volume diameter, median diameter) is not particularly limited and can be appropriately selected depending on the purpose. For example, it can be measured by laser diffraction / scattering, dynamic light scattering, image imaging, etc. Specific examples of the method for measuring the volume-average particle diameter include a method in which particles collected from the coating layer of the cleaning blade are measured by laser diffraction / scattering using a Microtrac (manufactured by Nikkiso Co., Ltd.), and a method in which fine particles on the cleaning blade are directly observed and measured using a scanning electron microscope (SEM). The volume-average particle diameter of the particles when added to the dispersion liquid to be applied to the cleaning blade is almost the same as that when present in the coating layer.

[0027] The content of the particles in the coating layer is not particularly limited and can be selected depending on the purpose. However, the content is preferably 80% by mass or more and 99% by mass or less, and more preferably 90% by mass or more and 98% by mass or less, based on the total mass of the coating layer, because a sliding effect is obtained and the coating layer becomes brittle and the particles tend to detach because the content is relatively greater than the binding component.

[0028] The material of the particles is not particularly limited and can be selected depending on the purpose, and examples thereof include polytetrafluoroethylene (PTFE), fluorinated ethylene-propylene copolymer (FEP), perfluoroalkoxy polymer (PFA), chlorotrifluoroethylene copolymer (CTFE), tetrafluoroethylene-chlorotrifluoroethylene copolymer (TFE / CTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), polychlorotrifluoroethylene (PCTFE), etc. Among these, polytetrafluoroethylene (PTFE) is preferred in terms of further improving the sliding properties of the cleaning blade.

[0029] The polytetrafluoroethylene (PTFE) may be suitably synthesized or may be a commercially available product, such as Dyneon TF Micropowder TF-9201Z or Dyneon TF Micropowder TF-9207Z (both manufactured by 3M), Nano FLON119N or FLUORO E (both manufactured by Shamrock), TLP10F-1 (manufactured by DuPont-Mitsui Fluorochemicals), KTL-500F (manufactured by Kitamura Co., Ltd.), or Algoflon L203F (manufactured by Solvay).

[0030] In the present invention, by including a binder component in the coating layer, the adhesion of the particles to the cleaning blade substrate is improved, and detachment of the coating layer can be prevented. Therefore, curling of the cleaning blade and an increase in torque can be prevented. In one aspect of the present invention, the binder component is preferably a matrix in the sea-island structure of the coating layer. It is preferable to select the type and amount of resin added for the binder component relative to the particles so that the binder component forms a matrix.

[0031] The binder component is not particularly limited as long as it can disperse the particles uniformly and stably, and can be appropriately selected depending on the purpose, and examples thereof include vinylidene fluoride (VdF), hexafluoropropylene (HFP), tetrafluoroethylene (TFE), etc. Among these, from the viewpoints of lubricity and adhesion to the blade substrate, copolymers combining these are preferred, and a VdF-HFP-TFE ternary copolymer is more preferred.

[0032] The composition of VdF / HFP / TFE in the terpolymer is preferably 30 mol% to 80 mol% / 10 mol% to 35 mol% / 5 mol% to 35 mol% of the respective monomer units in order to impart flexibility and solubility in a solvent to the blade.

[0033] The particles and the binder component are not limited to the examples given above and can be appropriately selected depending on the purpose, and examples thereof include inorganic compound particles, acrylic resins, styrene resins, vinyl resins, etc. Examples of inorganic compound particles include silica, alumina, zirconia, etc. These may be used alone or in combination of two or more.

[0034] The particles other than the fluorine-based resin are preferably acrylic resins, which have a certain degree of hardness and are therefore expected to have a sliding effect.On the other hand, the shape is not particularly limited and can be appropriately selected depending on the purpose, but spherical is preferred.This shape is preferable because it can prevent problems such as damage to the image carrier or the blade substrate of the cleaning blade caused by the particles other than the fluorine-based resin detached from the coating layer. The acrylic resin is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include polymethyl(meth)acrylic acid, styrene-methyl(meth)acrylate copolymer, styrene-ethyl(meth)acrylate copolymer, etc. The acrylic resin may be in the form of acrylic resin particles.

[0035] The volume average particle diameter (50% volume diameter, median diameter) of the particles other than the fluorine-based resin is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.1 μm or more and 1 μm or less, more preferably 0.5 μm or less, and even more preferably 0.3 μm or less. If the volume average particle diameter of the particles is 1 μm or less, the particles tend to settle in the solvent, making it difficult to stably disperse them. Furthermore, if the volume average particle diameter of the particles is 0.5 μm or less, they can be more stably dispersed in a non-aqueous solvent.

[0036] The method for producing the coating layer is not particularly limited and can be appropriately selected depending on the purpose. For example, the coating layer can be obtained by adding particles to a mixture of a solvent and a binder component, mixing them, and applying the resulting particle dispersion to the blade substrate of the cleaning blade.

[0037] The solvent is not particularly limited and can be appropriately selected depending on the purpose. For example, in the case of fluorine-based particles and a binding component, a fluorine-containing organic solvent can be used. Examples of the fluorine-containing organic solvent include hydrofluoroether (HFE), perfluorocarbon (PFC), and perfluoroether (PFE). These can be used alone or in combination of two or more.

[0038] In the present invention, the average particle size of the particles in the binder component as determined by dynamic light scattering (average particle size determined by cumulant analysis of scattering intensity distribution) is preferably 1 μm or less, more preferably 0.5 μm or less, and even more preferably 0.3 μm or less, in order to obtain a uniform dispersion. Usually, even when fine particles having a volume average particle size of 1 μm or less are used, the particles aggregate to form secondary particles, resulting in fine particles having a volume average particle size of 1 μm or more. By dispersing the aggregated fine particles to form secondary particles to a particle size of 1 μm or less, a stable dispersion can be obtained even when the fluororesin dispersion is stored at a low viscosity for a long period of time. The dispersion method is not particularly limited and can be appropriately selected depending on the purpose. Examples include methods using dispersing machines such as an ultrasonic disperser, a three-roll mill, a ball mill, a bead mill, and a jet mill.

[0039] The method for forming the coating layer is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include dipping, in which the entire blade substrate of the cleaning blade or a part of the blade substrate is immersed in a particle dispersion for treatment. In addition to dipping, coating methods such as spray coating and dispenser coating may also be used.

[0040] <Blade base> In the present invention, the blade substrate of the cleaning blade may be referred to as a "blade substrate" or a "substrate." The shape of the blade substrate may be selected appropriately depending on the purpose as long as it has a structure that can remove the residue on the image carrier, but it is preferable that the contact side at the contact portion between the blade substrate and the image carrier is linear. Examples of the shape of the blade substrate include a plate shape.

[0041] The structure of the blade substrate is not particularly limited and can be appropriately selected depending on the purpose. Examples include a single-layer structure, a laminated structure, and a laminated structure combining multiple components. Among these, a single-layer structure and a laminated structure combining multiple components are preferred from the viewpoint of ease of processing into the cleaning blade. When the blade substrate has a laminated structure, the layer that contacts the image carrier may be referred to as an edge layer, and the layer other than the edge layer may be referred to as a base layer. Note that when the blade substrate is a single layer, the blade substrate only has an edge layer. It is more preferred that the Martens hardness of each of the multiple components in the laminated structure is different from each other.

[0042] The material of the blade substrate is not particularly limited and can be selected appropriately depending on the purpose. However, from the viewpoint of preventing wear of the blade substrate and sufficiently removing the residue from the intermediate transfer body, it is preferable that the material has appropriate elasticity and hardness. Examples of the material of the blade include elastic materials. The elastic material is not particularly limited as long as it has high elasticity and can be selected appropriately depending on the purpose, and examples include polyurethane rubber, silicone rubber, fluororubber, nitrile rubber (NBR), and ethylene propylene diene rubber (EPDM). Among these, polyurethane rubber is preferred from the viewpoints of durability and non-contamination. The size of the blade substrate is not particularly limited and can be selected appropriately depending on the size of the image carrier.

[0043] The Martens hardness of the polyurethane rubber in the cleaning blade of the present invention is not particularly limited and can be appropriately selected depending on the purpose. 2 ] or more 2[N / mm 2 When the Martens hardness of the polyurethane rubber in the cleaning blade is within the desired range, it is possible to eliminate problems such as poor cleaning caused by difficulty in obtaining blade linear pressure and an increase in the area of ​​contact with the image carrier, and chipping caused by the blade substrate becoming too hard.

[0044] The method for producing the blade substrate is not particularly limited and can be selected appropriately depending on the purpose, but for example, a polyurethane prepolymer is prepared using a polyol compound and a polyisocyanate compound, a curing agent and, if necessary, a curing catalyst are added to the polyurethane prepolymer, the polyurethane prepolymer is centrifuged in a predetermined mold, and the resulting mixture is left to stand at room temperature to mature (cure), and then cut into a flat plate of predetermined dimensions to obtain the blade substrate. The polyol compound is not particularly limited and can be selected appropriately depending on the purpose, and examples thereof include high-molecular-weight polyols and low-molecular-weight polyols.

[0045] Examples of the high molecular weight polyol include polyester polyols, which are condensates of alkylene glycols and aliphatic dibasic acids; polyester polyols such as polyester polyols of alkylene glycols and adipic acid, such as ethylene adipate ester polyol, butylene adipate ester polyol, hexylene adipate ester polyol, ethylene propylene adipate ester polyol, ethylene butylene adipate ester polyol, and ethylene neopentylene adipate ester polyol; polycaprolactone polyols, such as polycaprolactone ester polyol obtained by ring-opening polymerization of caprolactone; and polyether polyols, such as poly(oxytetramethylene) glycol and poly(oxypropylene) glycol. These may be used alone or in combination of two or more.

[0046] Examples of the low-molecular-weight polyols include dihydric alcohols such as 1,4-butanediol, ethylene glycol, neopentyl glycol, hydroquinone-bis(2-hydroxyethyl)ether, 3,3'-dichloro-4,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenylmethane; and trihydric or higher polyhydric alcohols such as 1,1,1-trimethylolpropane, glycerin, 1,2,6-hexanetriol, 1,2,4-butanetriol, trimethylolethane, 1,1,1-tris(hydroxyethoxymethyl)propane, diglycerin, and pentaerythritol. These may be used alone or in combination of two or more.

[0047] The polyisocyanate compound is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include methylene diphenyl diisocyanate (MDI), tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), naphthylene 1,5-diisocyanate (NDI), tetramethyl xylene diisocyanate (TMXDI), isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate (H6XDI), dicyclohexylmethane diisocyanate (H12MDI), hexamethylene diisocyanate (HDI), dimer acid diisocyanate (DDI), norbornene diisocyanate (NBDI), trimethylhexamethylene diisocyanate (TMDI), etc. These may be used alone or in combination of two or more.

[0048] The curing agent is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include amines and alcohols. These may be used alone or in combination of two or more. The curing agent is used, for example, to adjust the hardness of the blade substrate.

[0049] The curing catalyst is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include 2-methylimidazole, 1,2-dimethylimidazole, etc. The content of the curing catalyst is not particularly limited and can be appropriately selected depending on the purpose, and is preferably 0.01% by mass or more and 0.5% by mass or less, and more preferably 0.05% by mass or more and 0.3% by mass or less, based on the total mass of the prepolymer and the curing agent.

[0050] The resilience coefficient of the blade substrate in accordance with JIS K6255 is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 10% to 80% at 23°C. Having the resilience coefficient within the desired range can eliminate problems such as poor cleaning caused by the loss of flexibility of the entire blade substrate and its inability to follow the vibrations or roughness of the image carrier, or blade squeal (abnormal noise) caused by excessive resilience. The resilience coefficient of the blade substrate can be measured, for example, in accordance with JIS K6255 at 23°C using a No. 221 resilience tester manufactured by Toyo Seiki Seisaku-sho, Ltd.

[0051] <Average value of brightness histogram> In the cleaning blade of the present invention, the average value of a luminance histogram at a position 100 μm inward from the edge of the coating layer on the underside of the cleaning blade substrate is 15,000 or more and 25,000 or less. The "position 100 μm inward from the edge" refers to, for example, the measurement point shown in Figure 3. By having the average value of the luminance histogram be 15,000 or more and 25,000 or less, the coating layer can be made sufficiently prone to crumbling. The average value of the luminance histogram can be obtained from a luminance image obtained by a confocal laser microscope. The luminance histogram obtained from the luminance image obtained by the confocal microscope is a histogram of the intensity of reflected light from the surface of the coating layer. The coating layer of the present invention is composed of particles and binder components. The coating layer being prone to crumbling means that there is relatively little binder component around the particles. This means that there are relatively more voids between the particles, which increases the reflected light from the surface of the coating layer and, as a result, increases the average value of the luminance histogram. In the cleaning blade of the present invention, the average value of the luminance histogram at a position 100 μm inward from the tip ridge of the edge layer is preferably 18,000 or more and 22,000 or less, from the viewpoint of achieving both a sliding effect and cleaning performance due to the film being more easily broken down. When the average value of the luminance histogram at a position 100 μm inward from the tip ridge of the edge layer of the cleaning blade is 15,000 or more, the coating layer is more easily broken down, which is preferable because it solves the problem of maintaining cleaning performance even when continuously printing high-density images. When the average value of the luminance histogram at a position 100 μm inward from the tip ridge of the edge layer of the cleaning blade is less than 15,000, the coating layer is less easily broken down, which makes it difficult to maintain cleaning performance when continuously printing high-density images. Conversely, if the average value of the brightness histogram exceeds 25,000, the coating layer will crumble too easily, making it impossible to maintain sliding properties, or the coating layer will fall off the cleaning blade when not in use.In the present invention, the average value of the luminance histogram is measured after processing into a cleaning blade.

[0052] -Measuring the average value of the brightness histogram- A confocal laser microscope (OLS-4100, Olympus) was used to obtain a brightness image of the coating surface using a 100x objective lens. The brightness histogram was obtained at 100 μm from the tip using the attached analysis application, and the average value was used.

[0053] <Measurement of Martens hardness> The location for measuring the Martens hardness of the base layer of the cleaning blade is not particularly limited, but for ease of measurement, it was set at a position 20 μm inward from the edge of the base layer. The Martens hardness was measured at 4 to 6 points at each measurement location, and the median value was shown. The Martens hardness was measured in accordance with ISO 14577 using a nanoindenter (ENT-3100, manufactured by Elionix) by continuously pressing a Berkovich indenter to a maximum load of 1,000 μN over 10 seconds, holding the load for 5 seconds, and then releasing the load at the same loading rate over 10 seconds.

[0054] [Image forming apparatus and image forming method] The image forming apparatus of the present invention comprises at least an image carrier, a charging unit for charging the surface of the image carrier, an exposure unit for exposing the charged image carrier to light to form an electrostatic latent image, a developing unit for developing the electrostatic latent image with toner to form a visible image, a transfer unit for transferring the visible image to a recording medium via an intermediate transfer member, a fixing unit for fixing the transferred image to the recording medium, and a cleaning unit for removing toner remaining on the intermediate transfer member, and may further comprise other units appropriately selected as necessary. The charging unit and the exposure unit may be collectively referred to as an electrostatic latent image forming unit. Each of the cleaning units includes the cleaning blade of the present invention. The image forming method used in the present invention includes at least a charging step, an exposure step, a development step, a transfer step, a fixing step, and a cleaning step, and may further comprise other units appropriately selected as necessary. The charging step and the exposure step may be collectively referred to as an electrostatic latent image forming step. The image forming method used in the present invention can be suitably carried out by the image forming apparatus of the present invention, and the charging step can be performed by the charging unit, the exposing step can be performed by the exposing unit, the developing step can be performed by the developing unit, the transferring step can be performed by the transferring unit, the fixing step can be performed by the fixing unit, the cleaning step can be performed by the cleaning unit, and the cleaning unit has the cleaning blade of the present invention. The other steps can be performed by the other units.

[0055] <Image carrier> The image carrier is not particularly limited in structure, size, etc., and can be appropriately selected from known ones. The shape of the image carrier is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a drum shape and a belt shape. The material of the image carrier is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include inorganic photoconductors such as amorphous silicon and selenium, and organic photoconductors (OPCs) such as polysilane and phthalopolymethine. Examples of the organic photoreceptor include a laminated photoreceptor having a laminated structure in which a layer (charge generation layer) in which a charge generation material such as metal-free phthalocyanine or titanyl phthalocyanine is dispersed in a binder resin and a layer (charge transport layer) in which a charge transport material is dispersed in a binder resin are stacked on a support such as an aluminum drum, and a single-layer photoreceptor having a single-layer photosensitive layer in which both a charge generation material and a charge transport material are dispersed in a binder resin on a support. In the single-layer photoreceptor, a hole transport material and an electron transport material can also be added to the photosensitive layer as charge transport materials. An undercoat layer may be provided between the support and the multilayer charge generating layer or the single-layer photosensitive layer.

[0056] <Charging Process and Charging Means> The charging step is a step of charging the surface of the image carrier, and is carried out by the charging device. The charging device is not particularly limited as long as it can charge the surface of the image carrier, and can be appropriately selected depending on the purpose. Examples include known contact chargers equipped with conductive or semiconductive rollers, brushes, films, rubber blades, etc., and non-contact chargers using corona discharge such as corotrons and scorotrons. The shape of the charging device may be any form, such as a roller, magnetic brush, or fur brush, and can be selected according to the specifications and shape of the electrophotographic image forming apparatus. When a magnetic brush is used, the magnetic brush uses various ferrite particles, such as Zn-Cu ferrite, as the charging device, and is composed of a nonmagnetic conductive sleeve for supporting the charging device and a magnet roll enclosed in the conductive sleeve. When a brush is used, for example, fur treated with a conductive material such as carbon, copper sulfide, metal, or metal oxide can be used as the material for the fur brush, and the charger can be made by wrapping or attaching it to a metal or other conductive core.

[0057] The charger is not limited to the contact-type charger described above, but is preferred in that it can provide an image forming apparatus in which ozone generation from the charger is reduced. The charger is preferably arranged in contact with or out of contact with the image carrier, and charges the surface of the image carrier by applying a superimposed DC and AC voltage. It is also preferred that the charger is a charging roller that has a gap tape on the image carrier and is arranged close to the image carrier but not in contact with it, and charges the surface of the image carrier by applying a superimposed DC and AC voltage to the charging roller.

[0058] <Exposure process and exposure means> The exposure step is a step of exposing the charged surface of the image carrier, and is performed by the exposure unit. The exposure can be performed, for example, by imagewise exposing the surface of the image carrier using the exposure unit. The optical systems used in the exposure are broadly classified into analog optical systems and digital optical systems. The analog optical system is an optical system that directly projects an original onto the surface of the image carrier. The digital optical system is an optical system that receives image information as an electrical signal, converts the electrical signal into an optical signal, and exposes the image carrier to form an image. The exposure unit is not particularly limited as long as it can expose the charged image carrier to form an electrostatic latent image, and can be appropriately selected depending on the purpose. Examples of the exposure unit include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, a liquid crystal shutter optical system, and an LED optical system. Note that the present invention may also employ a backlight system in which imagewise exposure is performed from the back side of the image carrier.

[0059] <Developing step and developing means> The developing process is a process of developing the electrostatic latent image into the toner image, and is carried out by the developing unit. The developing unit is not particularly limited as long as it can develop the electrostatic latent image into a toner image and can be appropriately selected depending on the purpose. For example, it can include a developing unit that contains the toner and can apply the toner to the electrostatic latent image in a contact or non-contact manner. The developing unit may be a dry or wet developing unit, and may be a monochromatic or multicolor developing unit. For example, it can include a developing unit that has an agitator that charges the toner by friction and a rotatable magnetic roller. In the developing unit, for example, the toner and, if necessary, a carrier are mixed and agitated, and the toner is charged by friction and held in a spiked state on the surface of the rotating magnetic roller, forming a magnetic brush. Since the magnetic roller is located near the image carrier, a portion of the toner constituting the magnetic brush formed on the surface of the magnetic roller moves to the surface of the image carrier due to the electrical attraction of the electrostatic latent image. As a result, the electrostatic latent image is developed with the toner, forming a toner image on the surface of the image carrier. The toner contained in the developing device may be a developer containing the toner, and the developer may be a one-component developer or a two-component developer. The toner may also be a one-component magnetic toner that does not use a carrier, or a non-magnetic toner. A premix development method may be adopted, in which a premix developer in which toner and carrier are premixed is replenished. In the premix development method, the excess carrier in the developing device is discharged as excess developer. This gradually refreshes the developer in the developing device. This can extend the replacement cycle due to deterioration of the developer and reduce the effort required for developer replacement.

[0060] <Transfer process and transfer means> The transfer step is a step of transferring the toner image to a recording medium and is performed by the transfer unit. The transfer step preferably includes, for example, a primary transfer step using an intermediate transfer member to transfer the toner image to the surface of the intermediate transfer member to form a composite transfer image, and a secondary transfer step of transferring the composite transfer image to a recording medium. The transfer unit is not particularly limited as long as it can transfer the toner image to a recording medium and can be appropriately selected depending on the purpose. A preferred embodiment includes a primary transfer unit that transfers the toner image to the surface of the intermediate transfer member to form a composite transfer image, and a secondary transfer unit that transfers the composite transfer image to a recording medium. The primary transfer unit and the secondary transfer unit preferably include, for example, a transfer device that peels and charges the toner image formed on the surface of the image carrier onto the recording medium. The transfer device is not particularly limited and can be appropriately selected depending on the purpose. Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device. The number of transfer devices may be one or more.

[0061] The recording medium is not particularly limited as long as it is capable of transferring the unfixed toner image after development, and can be appropriately selected depending on the purpose. A typical example is plain paper, but for example, a PET base for an OHP can also be used.

[0062] <Fixing process and fixing means> The fixing step is a step of fixing the toner image transferred to the recording medium, and is performed by the fixing device. When two or more colors of toner are used, each color of toner may be fixed as it is transferred to the recording medium, or all colors of toner may be transferred to the recording medium and fixed in a stacked state. The fixing device is not particularly limited as long as it can fix the toner image transferred to the recording medium and can be appropriately selected depending on the purpose, and a thermal fixing method using a known heating and pressurizing device can be used. The heating and pressurizing device is not particularly limited and can be appropriately selected depending on the purpose, and examples include a combination of a heating roller and a pressure roller, or a combination of a heating roller, a pressure roller, and an endless belt. The heating temperature is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 80°C to 200°C. If necessary, a known optical fixing device, for example, may be used together with the fixing device.

[0063] <Cleaning Process and Cleaning Means> The cleaning step is a step of removing the toner remaining on the surface of the image bearing member, and is carried out by the cleaning means, which is a cleaning blade of the present invention fixed to a support member.

[0064] The linear pressure applied by the blade substrate of the cleaning blade of the present invention to the surface of the image carrier is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 to 100 N / m, and more preferably 10 to 50 N / m. When the linear pressure is 10 to 100 N / m, cleaning defects caused by the toner slipping through the gap between the contact portion and the image carrier are less likely to occur, and curling of the elastic body can be more easily suppressed. The linear pressure can be measured, for example, using a measuring device incorporating a small compression load cell manufactured by Kyowa Electronics Co., Ltd.

[0065] In the cleaning blade of the present invention, the angle formed by the tangent to the image carrier at the position where the contact portion of the blade substrate contacts the tip surface of the free end of the blade substrate (hereinafter referred to as the "cleaning angle") is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 65° to 85°. When the cleaning angle is 65° to 85°, curling of the blade substrate can be easily suppressed and the occurrence of cleaning defects can be easily reduced.

[0066] <Other steps and other means> Examples of the other steps include a static elimination step, a recycling step, a control step, etc. Examples of the other means include a static elimination unit, a recycling unit, a control unit, etc.

[0067] (Static removal process and static removal means) The charge removal step is a step of removing static electricity by applying a static removal bias voltage to the image bearing member, and is performed by the static removal unit. The static removal unit is not particularly limited as long as it can apply a static removal bias voltage to the image bearing member, and can be appropriately selected depending on the purpose, and examples thereof include a static removal lamp.

[0068] (Recycling process and recycling means) The recycling step is a step of recycling the toner removed by the cleaning step to the developing unit, and is carried out by the recycling unit. The recycling unit is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include known conveying units.

[0069] (Control process and control means) The control step is a step of controlling each of the steps, and is carried out by a control means. The control means is not particularly limited as long as it can control the operation of each of the steps, and can be appropriately selected depending on the purpose, and examples thereof include devices such as a sequencer and a computer.

[0070] Here, an example of an image forming apparatus according to the present invention will be described with reference to the drawings. However, the use of the cleaning blade of the present invention is not limited to these embodiments. In each drawing, the same components are denoted by the same reference numerals, and duplicated explanations may be omitted. Furthermore, the number, position, shape, etc. of the following components are not limited to this embodiment, and may be any number, position, shape, etc. that is preferable for implementing the present invention.

[0071] 5 is a schematic diagram showing an example of an image forming apparatus of the present invention. This image forming apparatus is equipped with four imaging units for yellow, magenta, cyan, and black (hereinafter sometimes referred to as Y, M, C, and BK). These units use different colors of Y, M, C, and K toner as image-forming substances to form images, but are otherwise similar in configuration.

[0072] Each imaging unit includes a photosensitive drum 21 (cyan photosensitive drum 21C, yellow photosensitive drum 21Y, magenta photosensitive drum 21M, and black photosensitive drum 21BK), a charging unit that uniformly charges the photosensitive drum 21, an exposure device 12 that exposes the photosensitive drum 21 to light based on image information for each color and forms a latent image of that color on the photosensitive drum 21, a developing unit that develops the latent image with a developer of that color to form a toner image of that color (cyan developing device 20C, yellow developing device 20Y, magenta developing device 20M, and black developing device 20BK), a transfer charger that transfers the toner image onto the intermediate transfer belt 22, a cleaning device 13, and a de-electrification lamp. The charging unit is a charging member provided in the charging device as charging means, and the developing device 20 is developing means that converts the latent image formed on the surface of the photosensitive drum 21 into a toner image. The cleaning device 13 is a cleaning means for cleaning toner remaining on the photosensitive drum 21 after the toner image has been transferred to the intermediate transfer belt 22. A discharging lamp (not shown) is a discharging means for removing the surface potential of the photosensitive drum 21 after cleaning. Although the photosensitive drum 21 is shown in the form of a drum, it may also be in the form of a sheet or an endless belt. [Example]

[0073] Examples and Reference Examples of the present invention will be described below, but the present invention is not limited to these Examples. However, "parts" means "parts by mass" unless otherwise specified. Below, an embodiment in which the cleaning blade substrate shown in Figure 4 is composed of an elastic edge layer and a base layer will be described.

[0074] (Preparation of particle dispersion for forming coating layer) -Preparation of particle dispersion A- Particle Dispersion A was prepared by placing 6.8 parts of polytetrafluoroethylene (PTFE) micropowder (TF9201Z, manufactured by 3M, volume average particle diameter 200 nm) as particles, 0.2 parts of a VdF-HFP-TFE ternary copolymer consisting of vinylidene fluoride (VdF), hexafluoropropylene (HFP), and tetrafluoroethylene (TFE) as a binder component, and 93.0 parts of 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether (HFE-347; manufactured by Tokyo Chemical Industry Co., Ltd.) as a fluorine-based dispersion solvent in a screw tube and stirring with a stirrer or the like.

[0075] - Preparation of particle dispersion B - [Particle Dispersion B] was prepared by placing 6.9 parts of polytetrafluoroethylene (PTFE) micropowder (TF9201Z, manufactured by 3M, volume average particle diameter 200 nm) as particles, 0.1 parts of a VdF-HFP-TFE ternary copolymer as a binder component, and 93.0 parts of 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether (HFE-347; manufactured by Tokyo Chemical Industry Co., Ltd.) as a fluorine-based dispersion solvent in a screw tube and stirring with a stirrer or the like.

[0076] - Preparation of particle dispersion C - Particle dispersion C was prepared by placing 5.8 parts of polytetrafluoroethylene (PTFE) micropowder (TF9201Z, manufactured by 3M, volume average particle diameter 200 nm) as particles, 1.2 parts of a VdF-HFP-TFE ternary copolymer as a binder component, and 93.0 parts of 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether (HFE-347, manufactured by Tokyo Chemical Industry Co., Ltd.) as a fluorine-based dispersion solvent in a screw tube and stirring with a stirrer or the like.

[0077] -Preparation of particle dispersion D- Particle dispersion D was prepared by placing 97.0 parts of a polymethyl methacrylate (PMMA) aqueous dispersion (MX100W, manufactured by Nippon Shokubai Co., Ltd., volume average particle diameter 150 nm) as particles and 3.0 parts of a polyvinyl butyral (PVB) resin (S-LEC KW-10, manufactured by Sekisui Chemical Co., Ltd., acetalization degree 9±2 mol%) as a binding component in a screw tube and stirring with a stirrer or the like.

[0078] -Preparation of particle dispersion E- Particle dispersion E was prepared by placing 95.0 parts of a polymethyl methacrylate (PMMA) aqueous dispersion (MX100W, manufactured by Nippon Shokubai Co., Ltd., volume average particle diameter 150 nm) as particles and 5.0 parts of a polyvinyl alcohol (PVA) resin (Poval JP-03, manufactured by Nippon Acetic Acid Vinyl Poval Co., Ltd., saponification degree 88±2 mol%) as a binding component in a screw tube and stirring with a stirrer or the like.

[0079] Example 1 (Preparation of Blade Substrate for Cleaning Blade) The edge layer and base layer were made of polyurethane elastomer sheets molded by centrifugal molding, cured, and post-crosslinked. The average thickness and Martens hardness (HM) of the edge layer and base layer were as follows: Average thickness: 2.0 mm Martens hardness (HM) of the edge layer: 0.5 [N / mm 2 ] Martens hardness (HM) of the base layer: 1.1 [N / mm2 ] The edge layer and the base layer were bonded together to form a blade substrate, which was then bonded to a metal plate.

[0080] (Formation of coating layer: dipping) One end surface of the peripheral side surface to be used as the tip of the cleaning blade (hereinafter sometimes referred to as the cleaning blade tip surface) was immersed in the Particle Dispersion A at a right angle to the horizontal plane to a depth of 2 mm from the tip surface of the cleaning blade, and then pulled up at a pulling speed of 1 mm / s. In order to collect PTFE particles necessary for cleaning function in the part of the tip surface of the cleaning blade including the contact edge, the cleaning blade was tilted at about 45° as shown in Figure 6 and dried at room temperature (25°C) for 30 minutes to produce the cleaning blade of Example 1. The average thickness of the coating layer was 0.5 μm.

[0081] <Examples 2 to 7 and Comparative Examples 1 to 3> Cleaning blades of Examples 2 to 7 and Comparative Examples 1 to 3 were produced in the same manner as in Example 1, except that the type of particle dispersion, the Martens hardness of the base layer, and the average thickness of the coating layer were changed as shown in Table 1. The thickness of the coating layer was controlled by the pulling speed during dipping. The thickness increased as the pulling speed increased. Comparative Example 1 is a cleaning blade having a blade substrate with no coating layer.

[0082] <Assembly of image forming device> The cleaning blades obtained in Examples 1 to 7 and Comparative Examples 1 to 3 were attached to the image carrier unit of a color multifunction printer (imagio MP C4500, manufactured by Ricoh Co., Ltd.) (the printer section has a similar configuration to the image forming apparatus 500 shown in FIG. 5) to assemble an image forming apparatus. The cleaning blades were attached to the image forming apparatus so that the linear pressure was 20 g / cm and the cleaning angle was 81°.

[0083] <Measurement of the average value of the brightness histogram> The average values ​​of the brightness histograms were measured for the cleaning blades obtained in Examples 1 to 7 and Comparative Examples 1 to 3. The method for measuring the average values ​​of the brightness histograms was the same as that described in the "Average Value of Brightness Histograms" section above. The average values ​​of the brightness histograms shown in Table 1 are the median values ​​of values ​​measured at 4 to 6 points at each measurement location.

[0084] <Measurement of Martens hardness> The Martens hardness of the base layer of the cleaning blades obtained in Examples 1 to 7 and Comparative Examples 1 to 3 was measured. The Martens hardness (HM) was measured under the same conditions as in the "Martens hardness measurement" described above. Specifically, in accordance with ISO 14577, a nanoindenter (ENT-3100, manufactured by Elionix) was used to continuously press a Berkovich indenter to a maximum load of 1,000 μN over 10 seconds, hold the load for 5 seconds, and then release the load at the same loading rate over 10 seconds. The results are shown in Table 1. The Martens hardness of the base layer was measured at a position 20 μm inward from the edge of the base layer. The Martens hardness was measured at each measurement location, and is the median of values ​​measured at 4 to 6 points.

[0085] <Measurement of the average thickness of the coating layer> The average thickness of the coating layer was measured for the cleaning blades obtained in Examples 1 to 7 and Comparative Examples 1 to 3. The results are shown in Table 1. The average thickness was measured by scraping off a portion of the coating layer with a spatula or cotton swab, and measuring the shape using a contact surface roughness meter (Surftest SJ-500, manufactured by Mitutoyo).

[0086] <Evaluation of torque increase rate> Using the image forming apparatus, printing was performed under the following conditions, and the rate of change in the increase in drive torque of the image carrier was measured. After printing, the tip of the cleaning blade was observed with a laser microscope (LEXT OLS4100, manufactured by Olympus Corporation), and the rate of increase in torque was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 1. Note that "initial" in the evaluation criteria refers to the period from the first sheet to the 500th sheet. Environment: 23℃ / 45%RH Paper feeding conditions: Blank chart Output quantity: 5,000 sheets (A4 landscape size) -Evaluation criteria- ⊚: The rate of change in torque increase was within 50% of the initial value, and the image carrier did not stop due to the increase in driving torque. Furthermore, when the tip of the cleaning blade was observed after output, there was no sign of peeling. ○: The rate of change in torque increase was within 50% of the initial value, and the image carrier did not stop due to the increase in drive torque. However, when the tip of the cleaning blade was observed after output, there were traces of peeling, but this was not enough to remove toner, so it does not pose a problem in actual use. x: The image carrier stopped due to an increase in torque, and when the tip of the cleaning blade was observed after output, there was a trace of turning over to the extent that toner was removed, which was problematic in practical use.

[0087] <Image quality evaluation (cleaning ability)> Using the image forming apparatus, output was performed under the following conditions. Thereafter, the tip of the cleaning blade and the surface of the image carrier were observed with a laser microscope (LEXT OLS4100, manufactured by Olympus Corporation) and evaluated based on the following evaluation criteria. The evaluation results are shown in Table 1. Environment: 27℃ / 80%RH Paper feeding conditions: All solid images continuously Output quantity: 2,000 sheets (A4 landscape size) -Evaluation criteria- ⊚: Toner that has slipped through due to poor cleaning cannot be visually confirmed on the printed paper or the image carrier, and no streaks of toner can be confirmed even when the image carrier is observed longitudinally with a microscope. ◯: Toner that has slipped through due to poor cleaning cannot be visually confirmed on the printed paper or the image carrier, but when the image carrier is observed in the longitudinal direction with a microscope, streaks of toner that have slipped through can be confirmed. x: Toner that has slipped through due to poor cleaning can be visually confirmed on the printed paper and on the image carrier.

[0088] [Table 1]

[0089] The present invention includes, for example, the following aspects. (1) A cleaning blade that contacts the surface of a member to be cleaned to remove residue from the surface of the member to be cleaned, the cleaning blade has a cleaning blade substrate having an elastic member and a cleaning blade support member that supports the cleaning blade substrate; the elastic member has a coating layer provided on a tip portion that contacts the member to be cleaned, A cleaning blade characterized in that the average value of a brightness histogram at a position 100 μm inward from the tip ridge line in the coating layer on the lower surface of the cleaning blade substrate is 15,000 or more and 25,000 or less. (2) A cleaning blade as described in (1) above, characterized in that the average value of a brightness histogram at a position 100 μm inward from the tip ridge line in the coating layer on the lower surface of the cleaning blade substrate is 18,000 or more and 22,000 or less. (3) A cleaning blade according to (1) or (2) above, wherein the thickness of the coating layer on the underside of the cleaning blade substrate is 0.5 μm or more and 10 μm or less at a position 100 μm inward from the tip ridge of the cleaning blade. (4) The cleaning blade according to any one of (1) to (3) above, wherein the coating layer is composed of particles and a resin that functions as a binding component between the particles and the elastic member. (5) The cleaning blade according to any one of (1) to (4) above, wherein the coating layer is a coating film made of PTFE particles and a fluorine-based resin, or a coating film made of acrylic particles and a polyvinyl alcohol resin or a polyvinyl acetal resin. (6) A cleaning blade according to any one of (1) to (5) above, wherein the substrate of the cleaning blade has a single layer structure of polyurethane rubber or a laminate structure in which multiple polyurethane rubber layers having different Martens hardnesses are laminated. (7) The substrate of the cleaning blade has a single layer structure of polyurethane rubber, and the Martens hardness of the polyurethane rubber is 0.5 [N / mm 2 ] or more 2[N / mm 2 ] or less. (8) A process cartridge comprising an image carrier, a charging means for charging the surface of the image carrier, an exposure means for exposing the charged surface of the image carrier to light to form an electrostatic latent image, at least one of a developing means for developing the electrostatic latent image into a toner image, and a transfer means for transferring the toner image to a recording medium, and a cleaning means for contacting the surface of the image carrier and removing residues on the surface of the image carrier, wherein the cleaning means has a cleaning blade described in any one of (1) to (7) above. (9) An image forming apparatus comprising: an image carrier; a charging means for charging the surface of the image carrier; an exposure means for exposing the charged surface of the image carrier to light to form an electrostatic latent image; a developing means for developing the electrostatic latent image into a toner image; a transfer means for transferring the toner image to a recording medium; a fixing means for fixing the toner image transferred to the recording medium; and a cleaning means for contacting the surface of the image carrier and removing residues from the surface of the image carrier, wherein the cleaning means has a cleaning blade described in any one of (1) to (7) above. [Explanation of symbols]

[0090] 1 Imaging unit 1Y Imaging unit (for yellow) 1C Imaging unit (for cyan) 1M Imaging unit (for magenta) 1K Imaging unit (for black) 10 Lubricant application device 100Y Toner cartridge (for yellow) 100C Toner cartridge (for cyan) 100M Toner cartridge (for magenta) 100K Toner cartridge (for black) 101 Fur brush 103 Solid lubricant 103a Lubricant pressure spring 103b Bracket 14 Intermediate transfer belt 151 First paper feed cassette 152 Second paper feed cassette 151a First paper feed roller 152a Second paper feed roller 153 Paper feed path 154 Pair of transport rollers 162 Belt cleaning unit 162a Belt cleaning blade 2 Frame 3 Image carrier 3Y Image carrier (for yellow) 3C Image carrier (for cyan) 3M Image carrier (for magenta) 3K Image carrier (for black) 4 Charging roller 40 Optical writing unit 41 Polygon mirror 5 Developing device 5Y Developing device (for yellow) 5C Developing device (for cyan) 5M Developing device (for magenta) 5K Developing device (for black) 51 Developing roller 52 Supply screw 53 Agitating screw 54 Doctor 55 Pair of registration rollers 6 Cleaning device 60 Transfer unit 62 Cleaning blade 62a Cleaning blade tip surface 62b Cleaning blade lower surface 62c Cleaning blade contact portion 62d Cleaning blade side surface 621 Cleaning blade support member 622 Cleaning blade base 622a Edge layer 622b Base layer 623 Covering layer 63 First bracket 64 Second bracket 66 Secondary transfer backup roller 67 Drive roller 68 Auxiliary roller 69 Tension roller 7 Primary transfer roller 7Y Primary transfer roller (for yellow) 7C Primary transfer roller (for cyan) 7M Primary transfer roller (for magenta) 7K Primary transfer roller (for black) 70 Secondary transfer roller 8 Charging roller cleaner 80 Fusing unit 81 Pressure heating roller 82 Fusing belt unit 83 Heating roller 84 Fusing belt 85 Tension roller 86 Drive roller 87 Pair of paper ejection rollers 88 Stack unit 500 Image forming deviceL Laser light P Recording medium [Prior art documents] [Patent documents]

[0091] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-147972 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-101551 [Patent Document 3] Patent No. 3278733 [Patent Document 4] Japanese Patent Application Publication No. 10-214009 [Patent Document 5] Japanese Patent Application Publication No. 6-348193 [Patent Document 6] Japanese Patent Application Laid-Open No. 2017-16083 [Patent Document 7] Patent No. 2853598

Claims

1. A cleaning blade that contacts the surface of a member to be cleaned to remove residue from the surface of the member to be cleaned, the cleaning blade has a cleaning blade substrate having an elastic member and a cleaning blade support member that supports the cleaning blade substrate; the elastic member has a coating layer provided on a tip portion that contacts the member to be cleaned, A cleaning blade characterized in that the average value of a luminance histogram at a position 100 μm inward from the tip ridge line of the coating layer on the lower surface of the cleaning blade substrate is 15,000 or more and 25,000 or less.

2. 2. The cleaning blade according to claim 1, wherein the average value of a luminance histogram at a position 100 μm inward from a tip ridge line of the coating layer on the lower surface of the cleaning blade substrate is 18,000 or more and 22,000 or less.

3. 3. The cleaning blade according to claim 1, wherein the coating layer on the lower surface of the cleaning blade substrate has a thickness of 0.5 μm to 10 μm at a position 100 μm inward from a tip ridge of the cleaning blade.

4. 3. The cleaning blade according to claim 1, wherein the coating layer is made up of particles and a resin that functions as a binding component between the particles and the elastic member.

5. 3. The cleaning blade according to claim 1, wherein the coating layer is a coating film made of PTFE particles and a fluorine-based resin, or a coating film made of acrylic particles and a polyvinyl alcohol resin or a polyvinyl acetal resin.

6. 3. The cleaning blade according to claim 1, wherein the substrate of the cleaning blade has a single layer structure of polyurethane rubber or a laminate structure in which a plurality of polyurethane rubber layers having different Martens hardnesses are laminated.

7. The substrate of the cleaning blade has a single layer structure of polyurethane rubber, and the Martens hardness of the polyurethane rubber is 0.5 [N / mm ２ ] or more 2 [N / mm ２ 6. The cleaning blade according to claim 5, wherein the surface roughness is equal to or less than 100 nm.

8. A process cartridge comprising an image carrier, at least one of a charging means for charging the surface of the image carrier, an exposure means for exposing the charged surface of the image carrier to light to form an electrostatic latent image, a developing means for developing the electrostatic latent image into a toner image, and a transfer means for transferring the toner image to a recording medium, and a cleaning means for contacting the surface of the image carrier and removing residues on the surface of the image carrier, wherein the cleaning means has the cleaning blade described in claim 1 or 2.

9. 3. An image forming apparatus comprising: an image carrier; charging means for charging the surface of said image carrier; exposure means for exposing the charged surface of said image carrier to light to form an electrostatic latent image; developing means for developing said electrostatic latent image into a toner image; transfer means for transferring said toner image to a recording medium; fixing means for fixing said toner image transferred to said recording medium; and cleaning means for contacting the surface of said image carrier to remove residue from the surface of said image carrier, said cleaning means having the cleaning blade according to claim 1 or 2.

Images