CLEANING BLADE, PROCESS CARTRIDGE AND IMAGE FORMING APPARATUS

Abstract

To provide a cleaning blade that can suppress increase of torque of a cleaning target member and can provide an excellent cleaning property even immediately after the blade starts to be used.SOLUTION: The present invention relates to a cleaning blade 62 having an elastic material 622 for removing materials remaining on a surface of a cleaning target material 3 by being in contact with the surface. The elastic material 622 has a coating layer 62d containing fluorine-based fine particles and a binding agent including at least fluorine-based oil. The coating layer 62d is formed in at least a part of a contact line where the elastic member 622 and the cleaning target member 3 are in contact with each other.SELECTED DRAWING: Figure 1

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 body in an image forming process is removed by a cleaning means.

[0003] As the cleaning means, a cleaning blade is used because of its simple structure and excellent cleaning performance. The cleaning blade is usually composed of 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 off, and remove the toner remaining on the image carrier surface.

[0004] In the cleaning means using the cleaning blade, the cleaning blade comes into contact with the image carrier, so friction occurs between the cleaning blade and the image carrier, and the torque, which is the force required to rotate the image carrier, increases, which may cause a problem that the image carrier stops. In addition, the contact portion may wear out due to the rubbing between the cleaning blade and the image carrier, causing the contact portion to turn over, and toner to slip through the turned over portion, resulting in a problem of poor cleaning.

[0005] For this reason, it has been proposed to apply a lubricant to the contact portion of the cleaning blade (see, for example, Patent Documents 1 and 2), or to modify the contact portion of the cleaning blade with a curable composition or the like (see, for example, Patent Documents 3 and 4). In addition, when the image forming apparatus is assembled and when the cleaning blade is replaced, a step called touch-up may be performed in which toner or a metal soap such as zinc stearate is applied to the contact portion of the cleaning blade to prevent the above-mentioned problems. Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a cleaning blade that can suppress an increase in torque of a member to be cleaned even immediately after the start of use, and can provide good cleaning performance. [Means for solving the problem]

[0007] The above problem is solved by the following configuration 1). 1) A cleaning blade having an elastic member that comes into contact with the surface of a member to be cleaned to remove residues on the surface of the member to be cleaned, the elastic member has a coating layer containing fluorine-based fine particles and a binding component containing at least a fluorine-based oil, The cleaning blade has a coating layer formed on at least a part of a contact side where the elastic member and the member to be cleaned come into contact with each other. Effect of the Invention

[0008] According to the present invention, it is possible to provide a cleaning blade that can suppress an increase in torque of a member to be cleaned even immediately after the start of use, and can provide good cleaning performance. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view of an example showing a state in which a cleaning blade is in contact with the surface of an image bearing member. [Diagram 2] FIG. 2 is a perspective view showing an example of the cleaning blade of the present invention. [Diagram 3]FIG. 3 is a schematic cross-sectional view showing an example of the image forming apparatus of the present invention. [Figure 4] FIG. 4 is a schematic cross-sectional view showing an example of an image forming unit in the image forming apparatus of FIG. [Diagram 5] FIG. 5 is a schematic diagram for explaining the method of forming the coating layer carried out in the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (cleaning blade) The cleaning blade of the present invention is a cleaning blade having an elastic member that comes into contact with the surface of a member to be cleaned and removes residues adhering to the member to be cleaned. The elastic member has a coating layer containing fluorine-based fine particles and a binding component containing at least a fluorine-based oil, and further has other components as required.

[0011] Usually, a process (commonly known as touch-up) is performed to apply toner or a metal soap such as zinc stearate to the tip of the blade when assembling a unit or replacing a blade, in order to increase the sliding property between the cleaning blade (hereinafter also referred to as "blade") and the image carrier (hereinafter also referred to as "photoconductor") so that the blade does not turn over, or to reduce the torque so that the photoconductor does not stop due to an increase in torque. As the image forming apparatus operates, toner gradually accumulates between the blade and the photoconductor, and when this state is reached, the behavior of the blade becomes stable, so the metal soap (touch-up agent) only needs to function until this state is reached.

[0012] However, conventional touch-up is often performed manually, which can lead to variations in the amount of touch-up agent applied depending on the person performing the touch-up.Furthermore, conventional touch-up agents have a problem in that they come off the cleaning blade before the behavior of the cleaning blade becomes stable. Due to these causes, before the behavior of the cleaning blade becomes stable, poor cleaning may occur due to curling of the cleaning blade, and the torque of the image bearing member may increase.

[0013] In addition, there is a trade-off between preventing torque increase and improving cleaning performance. If the contact portion of the cleaning blade is made smooth in order to prevent the torque increase, particles such as toner will slip through, and cleaning performance will deteriorate. Conversely, if the contact portion of the cleaning blade is made uneven in order to improve cleaning performance, the torque will increase. For this reason, it has been difficult to improve cleaning performance while preventing torque increase.

[0014] As one method for preventing an increase in torque while improving cleaning performance at the same time, a method of disposing particles (fine particles) on the contact portion of the cleaning blade has been proposed (see, for example, Patent Document 1 mentioned above). Patent Document 1 describes a cleaning blade coated with PMMA (polymethyl methacrylic acid) particles, which are dispersed in a fluorine-based solvent and dropped onto the tip of the blade, for the purpose of improving the sliding property between the cleaning blade and the photoreceptor. However, when the particles dispersed in a solvent are simply applied, the fine particles have a low adhesion to the cleaning blade and are therefore easily detached from the cleaning blade, which has left the problems of the cleaning blade turning over before the cleaning blade becomes stable and the torque of the image carrier increasing.

[0015] Therefore, the present inventors have studied a method for preventing the fine particles from being detached from the cleaning blade. As a result, they have found that the fine particles can be prevented from being detached by dispersing the fine particles in a binding component containing a fluorine-based oil, rather than dispersing the fine particles only in a solvent, and applying the dispersion to the cleaning blade. They have also found that the use of a fluorine-based oil can prevent the cleaning blade from curling up and the torque increase of the image carrier, leading to the completion of the present invention.

[0016] <Elastic material> The elastic member has a coating layer and may further have other members as required.

[0017] The elastic member is not particularly limited in shape, material, size, structure, etc., and can be appropriately selected depending on the purpose. Examples of the shape of the elastic member include a flat plate, a strip, a sheet, etc. The size of the elastic member is not particularly limited, and can be appropriately selected depending on the size of the member to be cleaned. The material of the elastic member is not particularly limited and can be appropriately selected depending on the purpose, but polyurethane rubber, polyurethane elastomer, etc. are preferable because they tend to provide high elasticity.

[0018] The elastic member is not particularly limited and can be appropriately selected depending on the purpose. For example, the elastic member can be produced by preparing a polyurethane prepolymer using a polyol compound and a polyisocyanate compound, adding a curing agent and, if necessary, a curing catalyst to the polyurethane prepolymer, crosslinking the polyurethane prepolymer in a specified mold, and then forming the post-crosslinked product in an oven into a sheet by centrifugal molding. The sheet is then left to stand at room temperature for aging, and then cut into a plate of specified dimensions.

[0019] The polyol compound is not particularly limited and can be appropriately selected depending on the purpose. Examples of the polyol compound include high molecular weight polyols and low molecular weight polyols. 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; polyether polyols such as poly(oxytetramethylene) glycol and poly(oxypropylene) glycol, etc. These may be used alone or in combination of two or more.

[0020] Examples of the low molecular weight polyol 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.

[0021] 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.

[0022] The curing catalyst is not particularly limited and can be appropriately selected depending on the purpose. Examples of the curing catalyst include 2-methylimidazole and 1,2-dimethylimidazole. The content of the curing catalyst is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.01% by mass to 0.5% by mass, and more preferably 0.05% by mass to 0.3% by mass.

[0023] The JIS-A hardness of the elastic member is not particularly limited and can be appropriately selected depending on the purpose, but is more preferably 65 degrees to 83 degrees. When the JIS-A hardness is within the preferred range, the following problems can be prevented. This makes it difficult to obtain blade line pressure, which increases the area of ​​contact with the image carrier, resulting in poor cleaning performance. A defect in which the product becomes too hard and is prone to chipping. The elastic member is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable to use a laminate in which two or more types of rubber having different JIS-A hardness are integrally molded, in that it can achieve both abrasion resistance and conformability. Here, the JIS-A hardness of the elastic member can be measured, for example, by using a micro rubber hardness meter MD-1 manufactured by Kobunshi Keiki Co., Ltd.

[0024] The resilience coefficient of the elastic member in accordance with JIS K6255 standard is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 36% to 73%, and more preferably 52% to 73%, at 23° C. If the resilience coefficient is within the preferred range, the following problems can be prevented. The elastic material as a whole loses flexibility, making it unable to follow the vibrations or roughness of the image carrier, resulting in poor cleaning. A problem where the repulsion was too strong, causing the blade to squeal. The resilience coefficient of the elastic member can be measured, for example, in accordance with JIS K6255 standard at 23° C. using a resilience tester No. 221 manufactured by Toyo Seiki Seisakusho Co., Ltd.

[0025] The average thickness of the elastic member is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1.0 mm to 3.0 mm.

[0026] <<Coating layer>> The covering layer (surface covering layer) is formed on at least a part of the contact side where the elastic member contacts a member to be cleaned, which will be described later. The covering layer is preferably formed on the entire contact side, and may be formed on the entire elastic member. The coating layer contains fluorine-based fine particles and a binding component containing at least a fluorine-based oil, and further contains other components as required. The amount of the fluorine-based fine particles in the coating layer is preferably 4 to 8% by mass, and more preferably 4.5 to 5.5% by mass. The content of the binder component in the coating layer is preferably 1.5 to 3 mass %, more preferably 1.8 to 2.2 mass %.

[0027] -Fluorine-based particles- Examples of fluorine-based microparticles (including fluorine-based resin microparticles and fluorine-based resin micropowder) 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), and the like. Among these, PTFE is preferred from the viewpoint of improving the effects of the present invention. Such PTFE fine particles and micropowder can be obtained by emulsion polymerization.

[0028] The fluorine-based fine particles made of polytetrafluoroethylene (PTFE) may be appropriately synthesized or may be commercially available products, such as Dyneon TF Micropowder TF-9201Z, Dyneon TF Micropowder TF-9207Z (both manufactured by 3M), Nano FLON119N, FLUORO E (both manufactured by Shamrock), TLP10F-1 (manufactured by Mitsui-DuPont Fluorochemicals), KTL-500F (manufactured by Kitamura Co., Ltd.), and Algoflon L203F (manufactured by SOLVAY).

[0029] The shape of the fluorine-based fine particles is not particularly limited and may be appropriately selected depending on the purpose, but is preferably spherical. The volume average particle diameter of the fluorine-based microparticles is not particularly limited and can be appropriately selected depending on the purpose, but the volume-based average particle diameter (50% volume diameter, median diameter) measured by a laser diffraction / scattering method, a dynamic light scattering method, an image imaging method, or the like is preferably 1 μm or less, more preferably 0.5 μm or less, and even more preferably 0.3 μm or less. When the volume average particle size is 1 μm or less, the particles tend to settle in the solvent, making it difficult to stably disperse the particles, which can be prevented, whereas when the volume average particle size is 0.5 μm or less, the particles can be more stably dispersed in the solvent. The volume average particle size of the fluorine-based fine particles is preferably 0.1 μm or more. Methods for measuring the volume average particle diameter of the fluorine-based microparticles include, for example, a method in which the microparticles are collected from a cleaning blade and then measured by a laser diffraction / scattering method using a Microtrac (manufactured by Nikkiso Co., Ltd.), and a method in which the microparticles on the cleaning blade are directly observed and measured using a scanning electron microscope (SEM). The volume average particle size of the fluorine-based fine particles is almost the same when they are added to the coating layer during the manufacture of the cleaning blade and when they are present in the coating layer.

[0030] In the present invention, fine particles other than fluorine-based fine particles can be used in combination as necessary, for example, fine particles of inorganic compounds and fine resin particles. Examples of the fine particles of inorganic compounds include silica, alumina, and zirconia. Examples of the fine resin particles include acrylic resins, styrene resins, and vinyl resins. These may be used alone or in combination of two or more.

[0031] -Binding component- The binder component contains at least a fluorine-based oil that can disperse the above-mentioned fluorine-based fine particles uniformly and stably. The fluorine-based oil not only functions as a binder, but can also further improve the sliding function. Examples of the fluorine-based oil include those having a tetrafluoroethylene (TFE) oligomer or perfluoroether as the main skeleton.

[0032] The fluorine-based oil having a perfluoroether as the main skeleton is not particularly limited and can be appropriately selected as long as it has sliding properties and does not inhibit the dispersion of the above-mentioned fluorine-based fine particles, but from the viewpoint of kinetic viscosity, a fluorine-based oil having a weight average molecular weight of about 2,000 to 3,500 is preferable. Examples of perfluoroether-based fluorine-based oils include PT-02 (weight average molecular weight 2000), PT-82 (weight average molecular weight 2800), and PT-53 (weight average molecular weight 3500) manufactured by Nicca Chemical. The weight average molecular weight can be measured by the GPC method (polystyrene equivalent) according to the usual method.

[0033] The binder component in the present invention may be composed of only fluorine-based oil, or may be a mixture of fluorine-based oil and fluorine-based resin. From the viewpoint of improving the effect of the present invention, the fluorine-based resin is preferably a VdF-HFP-TFE ternary copolymer composed of vinylidene fluoride (VdF), hexafluoropropylene (HFP) and tetrafluoroethylene (TFE). In the VdF-HFP-TFE ternary copolymer, from the viewpoint of flexibility as a binder component and solubility in a solvent, the composition of the VdF / HFP / TFE monomers is preferably 30-85 mol% / 10-35 mol% / 5-35 mol%. When the binder component in the present invention is a mixture of a fluorine-based oil and a fluorine-based resin, the proportion of the fluorine-based resin is preferably 90 to 99 mass %, more preferably 95 to 98 mass %, based on the total binder component.

[0034] -solvent- The binder component in the present invention may further contain a solvent. The solvent is not particularly limited and can be appropriately selected depending on the purpose. For example, a fluorine-containing organic solvent can be used. Examples of the fluorine-containing organic solvent include hydrofluoroethers (HFEs), perfluorocarbons (PFCs), and perfluoroethers (PFEs). These may be used alone or in combination of two or more. The proportion of the solvent is preferably 90 to 99 mass %, more preferably 97 to 98 mass %, based on the total amount of the binding components.

[0035] -Method of manufacturing the coating layer- 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 mixing a fluorine-containing organic solvent with a binder component, adding fluorine-based fine particles to the obtained mixture (binder component dispersion), mixing, and applying the mixture to the elastic member. In the present invention, it is desirable that the average particle size of the fluorine-based fine particles in the binder resin dispersion as determined by dynamic light scattering (average particle size as determined by cumulant method analysis in scattering intensity distribution) is 1 μm or less.

[0036] In general, when fine particles having a volume average particle size of 1 μm or less are used, the particles usually aggregate to become fine particles having a particle size of 1 μm or more as secondary particles. In the present invention, by dispersing the fluorine-based fine particles to have a particle diameter of 1 μm or less, a stable dispersion can be obtained even when the binder component dispersion is stored for a long period of time at a low viscosity. Examples of the dispersion method include a method using a dispersing machine such as an ultrasonic disperser, a three-roll mill, a ball mill, a bead mill, or a jet mill. The volume average particle size of the fine particles in the binder component dispersion 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.

[0037] The method for forming the coating layer is not particularly limited and can be appropriately selected depending on the purpose, and can be, for example, a method of treating the elastic member by dipping it into a dispersion of a binder component and fluorine-based fine particles. In addition to dipping, coating methods such as spray coating and dispenser are also usable.

[0038] <Parts to be cleaned> The material, shape, structure, size, etc. of the member to be cleaned are not particularly limited and can be appropriately selected depending on the purpose. Examples of the shape of the member to be cleaned include drum, belt, plate, sheet, etc. The size of the member to be cleaned is not particularly limited and can be appropriately selected depending on the purpose, but a size that is generally used is preferable.

[0039] The material of the member to be cleaned is not particularly limited and may be appropriately selected depending on the purpose, and examples of the material include metal, plastic, and ceramic. The member to be cleaned is not particularly limited and can be appropriately selected depending on the purpose. When the cleaning blade is applied to an image forming apparatus, for example, the member to be cleaned can be an image carrier.

[0040] <Residue> The residue is not particularly limited as long as it is attached to the surface of the member to be cleaned and is a target for removal by the cleaning blade, and may be appropriately selected depending on the purpose. Examples of the residue include toner, lubricant, inorganic fine particles, organic fine particles, dirt, dust, and mixtures thereof.

[0041] <Other materials> The other members are not particularly limited and can be appropriately selected depending on the purpose. For example, a support member can be mentioned. The shape, size, material, etc. of the support member are not particularly limited and can be appropriately selected depending on the purpose. Examples of the shape of the support member include a flat plate, a strip, a sheet, etc. The size of the support member is not particularly limited and can be appropriately selected depending on the size of the member to be cleaned. Examples of materials for the support member include metals, plastics, ceramics, etc. Among these, metal plates are preferred from the viewpoint of strength, and steel plates such as stainless steel, aluminum plates, and phosphor bronze plates are particularly preferred.

[0042] Here, an example of the cleaning blade in the present invention will be described with reference to the drawings. In addition, 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 the present embodiment, and may be any number, position, shape, etc. that is preferable for implementing the present invention.

[0043] FIG. 1 is a schematic cross-sectional view showing a state in which a cleaning blade 62 of the present invention is in contact with the surface of an image carrier 3, and FIG. 2 is a perspective view of the cleaning blade of FIG. 1 and an enlarged view of the vicinity of the contact portion. 1, the cleaning blade 62 is composed of a flat support member 621 made of a rigid material such as metal or hard plastic, and a flat elastic member 622. The elastic member 622 is fixed to one end of the support member 621 by adhesive or the like, and the other end of the support member 621 is supported at one end by a case of the cleaning device. Also shown are a blade tip surface 62a, a blade lower surface 62b, and a contact portion 62c (also referred to as a tip ridge portion, edge portion, etc.).

[0044] As shown in FIG. 2, the cleaning blade 62 is composed of a support member 621 and a flat elastic member 622 having one end connected to the support member 621 and the other end having a free end of a predetermined length, and is arranged so that a contact portion 62c, which is one end on the free end side of the elastic member 622, abuts against the surface of the image carrier along the longitudinal direction. The elastic member 622 has a coating layer 62d on at least a part of the contact portion 62c.

[0045] (Image forming apparatus and image forming method) The image forming apparatus of the present invention comprises at least an image carrier, a charging means for charging the surface of the image carrier, an exposure means for exposing the charged 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 to remove residues on the surface of the image carrier, and further comprises other means appropriately selected as necessary. The charging means and the exposure means may be collectively referred to as an electrostatic latent image forming means.

[0046] 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 further includes other steps appropriately selected as necessary. The charging step and the exposure step may be collectively referred to as an electrostatic latent image forming step.

[0047] 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 means, the exposure step can be performed by the exposure means, the developing step can be performed by the developing means, the transfer step can be performed by the transfer means, the fixing step can be performed by the fixing means, the cleaning step can be performed by the cleaning means, and the other steps can be performed by the other means.

[0048] <Image carrier> The image carrier (hereinafter sometimes referred to as "electrophotographic photoreceptor" or "photoreceptor") is not particularly limited in terms of its material, shape, structure, size, etc., and can be appropriately selected from known ones. Examples of the shape of the image carrier include a drum shape and a belt shape. Examples of the material of the image carrier include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors (OPC) such as polysilane and phthalopolymethine.

[0049] <Charging process and charging means> The charging step is a step of charging the surface of the image bearing member by the charging unit. The charging means is not particularly limited as long as it can charge the surface of the image bearing member, and can be appropriately selected depending on the purpose. Examples of the charging means include a contact charger known per se having a conductive or semiconductive roller, brush, film, rubber blade, etc., and a non-contact charger that utilizes corona discharge such as a corotron or scorotron. The shape of the charging means may be any shape, such as a roller, a magnetic brush, a fur brush, etc., 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 means, and is composed of a non-magnetic conductive sleeve for supporting the magnetic brush and a magnet roll contained therein. When a brush is used, for example, the material of the fur brush is fur that has been treated to be conductive with carbon, copper sulfide, metal, or metal oxide, and this is wound or attached to a metal or other conductive core to form a charger. The charger is not limited to the contact type charger described above, but has the advantage that an image forming apparatus in which ozone generated from the charger is reduced can be obtained. It is preferable that the charger is disposed in contact with or without contact with the image bearing member, and charges the surface of the image bearing member by applying DC and AC voltages in a superimposed manner. It is also preferred that the charger is a charging roller disposed close to the image carrier without contacting the image carrier with a gap tape, and that the surface of the image carrier is charged by applying DC and AC voltages in a superimposed manner to the charging roller.

[0050] <Exposure Step and Exposure Means> The exposure step is a step of exposing the charged surface of the image carrier to light, and is performed by the exposure unit. The exposure step can be performed, for example, by exposing the surface of the image carrier to light in an imagewise manner using the exposure unit. The optical system in the exposure is roughly divided into an analog optical system and a digital optical system. The analog optical system is an optical system that directly projects an original onto the surface of the image carrier by an optical system, while 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 means is not particularly limited as long as it can expose the charged image carrier to light to form an electrostatic latent image, and can be appropriately selected depending on the purpose. Examples of the exposure means 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. In the present invention, a backlight system in which exposure is performed imagewise from the back side of the image carrier may be adopted.

[0051] <Developing step and developing means> The developing step is a step of developing the electrostatic latent image into the toner image by the developing unit. The developing means 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, a developing means that contains the toner and has at least a developing unit that can apply the toner to the electrostatic latent image by contact or non-contact is preferably used. The developing device may be of a dry developing type or a wet developing type, and may be a single-color developing device or a multi-color developing device. For example, a suitable developing device includes an agitator that charges the toner by friction stirring, and a rotatable magnetic roller. In the developing device, for example, the toner and, if necessary, a carrier are mixed and stirred, and the toner is charged by friction during this process and held in a standing state on the surface of the rotating magnet roller to form a magnetic brush. Since the magnet roller is disposed in the vicinity of the image carrier, a part of the toner constituting the magnetic brush formed on the surface of the magnet roller moves to the surface of the image carrier by the electrical attraction force of the electrostatic latent image. As a result, the electrostatic latent image is developed by the toner to form the 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 can be used as a one-component magnetic toner that does not use a carrier, or as a non-magnetic toner.

[0052] <Transfer process and transfer means> The transfer step is a step of transferring the toner image onto a recording medium by the transfer unit. The transfer step preferably includes, for example, a primary transfer step in which an intermediate transfer body is used and the toner image is transferred to the surface of the intermediate transfer body to form a composite transfer image, and a secondary transfer step in which the composite transfer image is transferred to a recording medium. The transfer means is not particularly limited as long as it can transfer the toner image onto a recording medium, and can be appropriately selected depending on the purpose. A preferred embodiment has a primary transfer means that transfers the toner image onto the surface of the intermediate transfer body to form a composite transfer image, and a secondary transfer means that transfers the composite transfer image onto a recording medium. The primary transfer unit and the secondary transfer unit preferably have at least a transfer device that peels and charges the toner image formed on the surface of the image carrier onto a recording medium, for example. The transfer device is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, an adhesive transfer device, etc. The number of the transfer devices may be one or more.

[0053] 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.

[0054] <Fixing process and fixing means> The fixing step is a step of fixing the toner image transferred onto the recording medium by the fixing unit. When toners of two or more colors are used, the toners of each color may be fixed as they are transferred onto the recording medium, or the toners of all colors may be fixed in a laminated state after being transferred onto the recording medium. The fixing means 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. A thermal fixing method using a known heating and pressurizing means can be adopted. The heating and pressing means may be 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 may be appropriately selected depending on the purpose, but is preferably 80° C. to 200° C. If necessary, a known optical fixing device may be used together with the fixing means.

[0055] <Cleaning process and cleaning means> The cleaning step is a step of removing the toner remaining on the surface of the image bearing member by the cleaning means. As the cleaning means, the cleaning blade of the present invention fixed to a supporting member is used.

[0056] The linear pressure applied by the elastic member to the surface of the image carrier is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 N / m to 100 N / m, more preferably 10 N / m to 50 N / m. When the linear pressure is 10 N / m to 100 N / m, cleaning failure due to the toner slipping through between the contact portion and the member to be cleaned is unlikely to occur, and curling of the elastic body can be easily suppressed. The linear pressure can be measured, for example, by using a measuring device incorporating a small compression load cell manufactured by Kyowa Electric Industry Co., Ltd.

[0057] The angle between the tangent to the member to be cleaned at the position where the contact portion of the elastic member contacts and the tip surface of the free end of the elastic member (hereinafter referred to as the "cleaning angle") is not particularly limited and can be selected appropriately depending on the purpose, but it is preferably 65° or more and 85° or less. When the cleaning angle is 65° or more and 85° or less, the occurrence of curling of the elastic member can be easily suppressed, and the occurrence of cleaning defects can be easily reduced.

[0058] <Other steps and other means> Examples of the other steps include a static elimination step, a recycling step, and a control step. Examples of the other means include a static elimination means, a recycling means, and a control means.

[0059] -Static charge removal process and static charge removal means- The charge removing step is a step of removing electricity by applying a charge removing bias voltage to the image bearing member, and is performed by the charge removing unit. The charge removing means is not particularly limited as long as it can apply a charge removing bias voltage to the image bearing member, and can be appropriately selected depending on the purpose. For example, a charge removing lamp can be used.

[0060] -Recycling process and methods- The recycling step is a step of recycling the toner removed in the cleaning step to the developing means, and is performed by the recycling means. The recycling means is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include known transport means.

[0061] -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 movement of each of the means, and can be appropriately selected depending on the purpose. Examples of the control means include devices such as a sequencer and a computer.

[0062] Here, an example of an image forming apparatus of the present invention will be described with reference to the drawings. 3 is a schematic diagram showing an example of an image forming apparatus 500 of the present invention. This image forming apparatus 500 is equipped with four imaging units 1Y, 1C, 1M, and 1K for yellow, magenta, cyan, and black (hereinafter sometimes referred to as Y, C, M, and K). These units use different colors of Y, C, M, and K toner as image forming substances for forming images, but otherwise have the same configuration.

[0063] A transfer unit 60 including an intermediate transfer belt 14 as an intermediate transfer body is disposed above the four image forming units 1. The toner images of the respective colors formed on the surfaces of the photoconductors 3Y, 3C, 3M, and 3K included in the image forming units 1Y, 1C, 1M, and 1K, which will be described in detail later, are transferred onto the surface of the intermediate transfer belt 14 in a superimposed manner. An optical writing unit 40 is disposed below the four imaging units 1. The optical writing unit 40, which is a latent image forming means, irradiates the photoconductors 3Y, 3C, 3M, and 3K of the imaging units 1Y, 1C, 1M, and 1K with laser light L emitted based on image information. As a result, electrostatic latent images for Y, C, M, and K are formed on the photoconductors 3Y, 3C, 3M, and 3K. The optical writing unit 40 irradiates the laser light L emitted from a light source onto the photoconductors 3Y, 3C, 3M, and 3K through a plurality of optical lenses and mirrors while polarizing the laser light L by a polygon mirror 41 that is driven to rotate by a motor. Instead of the above configuration, an optical scanning unit using an LED array may be used.

[0064] Below the optical writing unit 40, a first paper feed cassette 151 and a second paper feed cassette 152 are arranged so as to be stacked vertically. In each of these paper feed cassettes, a plurality of recording media P are stored in a stack of paper, and a first paper feed roller 151a and a second paper feed roller 152a are in contact with the top recording medium P. When the first paper feed roller 151a is driven to rotate counterclockwise in FIG. 3 by a driving means (not shown), the top recording medium P in the first paper feed cassette 151 is discharged toward a paper feed path 153 disposed to extend vertically on the right side of the cassette in FIG. 3. When the second paper feed roller 152a is driven to rotate counterclockwise in FIG. 3 by a driving means (not shown), the top recording medium P in the second paper feed cassette 152 is discharged toward the paper feed path 153.

[0065] A plurality of conveying roller pairs 154 are disposed in the paper feed path 153. The recording medium P sent into the paper feed path 153 is conveyed in the paper feed path 153 from the lower side to the upper side in FIG. 3 while being sandwiched between the rollers of the conveying roller pairs 154.

[0066] A pair of registration rollers 55 is disposed at the downstream end in the transport direction of the paper feed path 153. As soon as the pair of registration rollers 55 sandwiches the recording medium P fed from the pair of transport rollers 154 between the rollers, the pair of registration rollers 55 temporarily stops the rotation of both rollers. Then, the pair of registration rollers 55 sends the recording medium P toward a secondary transfer nip, which will be described later, at an appropriate timing.

[0067] FIG. 4 is a schematic diagram showing the configuration of one of the four image forming units 1. As shown in FIG. 4, the imaging unit 1 includes a drum-shaped photoconductor 3 serving as an image carrier. Although the photoconductor 3 is shown in a drum-like shape, it may be in the form of a sheet or an endless belt. Around the photoconductor 3, a charging roller 4, a developing device 5, a primary transfer roller 7, a cleaning device 6, a lubricant application device 10, and a discharging lamp (not shown) are arranged. The charging roller 4 is a charging member provided in a charging device as a charging means, and the developing device 5 is a developing means for converting a latent image formed on the surface of the photoconductor 3 into a toner image. The primary transfer roller 7 is a primary transfer member provided in a primary transfer device as a primary transfer means for transferring a toner image on the surface of the photoconductor 3 to an intermediate transfer belt 14. The cleaning device 6 is a cleaning means for cleaning toner remaining on the photoconductor 3 after the toner image is transferred to the intermediate transfer belt 14. The lubricant application device 10 is a lubricant application means for applying a lubricant to the surface of the photoconductor 3 after cleaning by the cleaning device 6. The discharging lamp (not shown) is a discharging means for discharging the surface potential of the photoconductor 3 after cleaning.

[0068] The charging roller 4 is disposed at a predetermined distance from the photoconductor 3 in a non-contact manner, and charges the photoconductor 3 to a predetermined polarity and a predetermined potential. The surface of the photoconductor 3 that has been uniformly charged by the charging roller 4 is irradiated with laser light L from an optical writing unit 40, which is a latent image forming means, based on image information, and an electrostatic latent image is formed. The developing device 5 has a developing roller 51 as a developer carrier. A developing bias is applied to the developing roller 51 from a power source (not shown). A supply screw 52 and an agitating screw 53 are provided in a casing of the developing device 5 to agitate the developer contained in the casing while transporting the developer in opposite directions. A doctor 54 is also provided to regulate the developer carried by the developing roller 51. The toner in the developer agitated and transported by the two screws, the supply screw 52 and the agitating screw 53, is charged to a predetermined polarity. The developer is then pumped up onto the surface of the developing roller 51, and the pumped up developer is regulated by the doctor 54, and the toner adheres to the latent image on the photoconductor 3 in a development area facing the photoconductor 3.

[0069] The cleaning device 6 includes a fur brush 101 and a cleaning blade 62. The cleaning blade 62 contacts the photoreceptor 3 in a counter direction to the surface movement direction of the photoreceptor 3. The details of the cleaning blade 62 are as described above. The lubricant applicator 10 includes a solid lubricant 103, a lubricant pressure spring 103a, etc., and uses a fur brush 101 as an applicator brush that applies the solid lubricant 103 onto the photoreceptor 3. The solid lubricant 103 is held by a bracket 103b, and is pressed toward the fur brush 101 by the lubricant pressure spring 103a. The solid lubricant 103 is scraped off by the fur brush 101, which rotates in the same direction as the rotation direction of the photoreceptor 3, and the lubricant is applied onto the photoreceptor 3. By applying the lubricant to the photoreceptor, the friction coefficient of the surface of the photoreceptor 3 is maintained at 0.2 or less during non-image formation.

[0070] The charging device is a non-contact close-by arrangement type in which the charging roller 4 is placed close to the photoconductor 3, but the charging device may be of any known configuration, including a corotron, scorotron, or solid-state charger. Of these charging methods, the contact charging method or the non-contact close-by arrangement method is more desirable, and has the advantages of high charging efficiency, low ozone generation, and the ability to miniaturize the device.

[0071] The light source for the laser light L of the optical writing unit 40 and the light source for the discharge lamp can be any light-emitting material such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light-emitting diode (LED), a semiconductor laser (LD), or an electroluminescence (EL). In order to irradiate only light in a desired wavelength range, various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used. Of these light sources, light emitting diodes and semiconductor lasers are preferably used since they have high irradiation energy and emit light with a long wavelength of 600 nm or more and 800 nm or less.

[0072] The transfer unit 60 as a transfer means shown in FIG. 3 includes the intermediate transfer belt 14, a belt cleaning unit 162, a first bracket 63, a second bracket 64, and the like. It also includes four primary transfer rollers 7Y, 7C, 7M, and 7K, a secondary transfer backup roller 66, a drive roller 67, an auxiliary roller 68, and a tension roller 69. The intermediate transfer belt 14 is endlessly moved counterclockwise in FIG. 3 by the rotational drive of the drive roller 67 while being stretched around these eight roller members. The four primary transfer rollers 7Y, 7C, 7M, and 7K sandwich the intermediate transfer belt 14 thus endlessly moved between the photoconductors 3Y, 3C, 3M, and 3K to form primary transfer nips. A transfer bias of the opposite polarity (for example, positive) to that of the toner is applied to the back surface (loop inner peripheral surface) of the intermediate transfer belt 14. As the intermediate transfer belt 14 moves endlessly, it passes through the primary transfer nips for Y, C, M, and K in sequence, and the Y, C, M, and K toner images on the photoconductors 3Y, 3C, 3M, and 3K are primarily transferred onto the front surface of the intermediate transfer belt 14 in a superimposed manner. As a result, a four-color superimposed toner image (hereinafter sometimes referred to as a four-color toner image) is formed on the intermediate transfer belt 14.

[0073] The secondary transfer backup roller 66 sandwiches the intermediate transfer belt 14 between itself and a secondary transfer roller 70 disposed outside the loop of the intermediate transfer belt 14 to form a secondary transfer nip. The registration roller pair 55 described above sends the recording medium P sandwiched between the rollers toward the secondary transfer nip at a timing that allows synchronization with the four-color toner image on the intermediate transfer belt 14. The four-color toner image on the intermediate transfer belt 14 is collectively secondarily transferred to the recording medium P in the secondary transfer nip by the influence of the secondary transfer electric field formed between the secondary transfer roller 70 to which a secondary transfer bias is applied and the secondary transfer backup roller 66, and the nip pressure. Then, combined with the white color of the recording medium P, it becomes a full-color toner image.

[0074] After passing through the secondary transfer nip, residual toner that has not been transferred to the recording medium P adheres to the intermediate transfer belt 14. This is cleaned by a belt cleaning unit 162. The belt cleaning unit 162 brings a belt cleaning blade 162a into contact with the front surface of the intermediate transfer belt 14, thereby scraping off and removing the residual toner on the intermediate transfer belt 14.

[0075] The first bracket 63 of the transfer unit 60 is adapted to swing at a predetermined rotation angle around the rotation axis of the auxiliary roller 68 as the drive of a solenoid (not shown) is turned on and off. When forming a monochrome image, the image forming apparatus 500 rotates the first bracket 63 slightly counterclockwise in FIG. 3 by driving the above-mentioned solenoid. This rotation causes the primary transfer rollers 7Y, 7C, and 7M for Y, C, and M to revolve around the rotation axis of the auxiliary roller 68 counterclockwise in FIG. 3, thereby separating the intermediate transfer belt 14 from the photoconductors 3Y, 3C, and 3M for Y, C, and M. Then, of the four imaging units 1Y, 1C, 1M, and 1K, only the imaging unit 1K for K is driven to form a monochrome image. This makes it possible to avoid wear and tear of each member constituting the imaging unit 1 due to unnecessary driving of the imaging units 1 for Y, C, and M during monochrome image formation.

[0076] A fixing unit 80 is disposed above the secondary transfer nip in FIG. 3. The fixing unit 80 includes a pressure heating roller 81 containing a heat source such as a halogen lamp, and a fixing belt unit 82. The fixing belt unit 82 includes a fixing member, a heating roller 83 containing a heat source such as a halogen lamp, a tension roller 85, a driving roller 86, a temperature sensor (not shown), and the like. The endless fixing belt 84 is stretched by the heating roller 83, the tension roller 85, and the driving roller 86 and moves endlessly in the counterclockwise direction in FIG. 3. During this endless movement, the fixing belt 84 is heated from the back side by the heating roller 83. The pressure heating roller 81, which is driven to rotate in the clockwise direction in FIG. 3, abuts on the front side of the fixing belt 84, which is heated in this way, at the portion where the fixing belt 84 is wrapped around the heating roller 83. As a result, a fixing nip is formed where the pressure heating roller 81 and the fixing belt 84 abut on each other.

[0077] A temperature sensor (not shown) is disposed outside the loop of the fixing belt 84 so as to face the front surface of the fixing belt 84 with a predetermined gap therebetween, and detects the surface temperature of the fixing belt 84 immediately before it enters the fixing nip. The detection result is sent to a fixing power circuit (not shown). The fixing power circuit controls the on / off supply of power to the heat source contained in the heating roller 83 and the heat source contained in the pressure heating roller 81 based on the detection result by the temperature sensor.

[0078] The recording medium P that has passed through the secondary transfer nip described above is separated from the intermediate transfer belt 14 and then sent into the fixing unit 80. Then, in the process of being conveyed from the bottom to the top in FIG. 3 while being sandwiched in the fixing nip inside the fixing unit 80, the recording medium P is heated and pressed by the fixing belt 84, whereby the full-color toner image is fixed onto the recording medium P.

[0079] The recording medium P thus subjected to the fixing process is discharged outside the image forming apparatus after passing between the rollers of the discharge roller pair 87. A stack section 88 is formed on the upper surface of the housing of the main body of the image forming apparatus 500, and the recording medium P discharged outside the image forming apparatus by the discharge roller pair 87 is stacked in this stack section 88 in order.

[0080] Four toner cartridges 100Y, 100C, 100M, and 100K containing Y, C, M, and K toners are disposed above the transfer unit 60. The Y, C, M, and K toners in the toner cartridges 100Y, 100C, 100M, and 100K are appropriately supplied to the developing devices 5Y, 5C, 5M, and 5K of the image forming units 1Y, 1C, 1M, and 1K. These toner cartridges 100Y, 100C, 100M, and 100K are detachable from the image forming apparatus main body independently of the image forming units 1Y, 1C, 1M, and 1K.

[0081] Next, the image forming operation in the image forming apparatus 500 will be described. First, when a print execution signal is received from an operation unit (not shown) or the like, a predetermined voltage or current is sequentially applied at a predetermined timing to the charging roller 4 and the developing roller 51. Similarly, a predetermined voltage or current is sequentially applied at a predetermined timing to the optical writing unit 40 and light sources such as a static electricity removal lamp. Synchronously with this, the photoconductor 3 is rotated in the direction of the arrow in FIG. 3 by a photoconductor drive motor (not shown) serving as a drive means.

[0082] 4, the surface of the photoreceptor 3 is first uniformly charged to a predetermined potential by the charging roller 4. Then, laser light L corresponding to image information is irradiated onto the photoreceptor 3 from the optical writing unit 40, and the portion on the surface of the photoreceptor 3 irradiated with the laser light L is neutralized to form an electrostatic latent image. The surface of the photoconductor 3 on which the electrostatic latent image is formed is rubbed by a magnetic brush of developer formed on the developing roller 51 at the portion facing the developing device 5. At this time, the negatively charged toner on the developing roller 51 moves to the electrostatic latent image side by a predetermined developing bias applied to the developing roller 51, and is turned into a toner image (developed). A similar image forming process is performed in each imaging unit 1, and a toner image of each color is formed on the surface of each photoconductor 3Y, 3C, 3M, 3K of each imaging unit 1Y, 1C, 1M, 1K. In this manner, in the image forming apparatus 500, the electrostatic latent image formed on the photoconductor 3 is reverse-developed by the developing device 5 with negatively charged toner. In the present embodiment, an example using an N / P (negative / positive: toner adheres to areas with low potential) non-contact charging roller method has been described, but the present invention is not limited to this.

[0083] The toner images of each color formed on the surface of each of the photoconductors 3Y, 3C, 3M, and 3K are sequentially primarily transferred so as to be superimposed on the surface of the intermediate transfer belt 14. As a result, a four-color toner image is formed on the intermediate transfer belt 14. The four-color toner image formed on the intermediate transfer belt 14 is transferred onto the recording medium P, which is fed from the first paper feed cassette 151 or the second paper feed cassette 152 and passes between the rollers of the registration roller pair 55 and is fed to the secondary transfer nip. At this time, the recording medium P is stopped once while being sandwiched between the registration roller pair 55, and is fed to the secondary transfer nip in synchronization with the leading edge of the image on the intermediate transfer belt 14. The recording medium P onto which the toner image has been transferred is separated from the intermediate transfer belt 14 and conveyed to the fixing unit 80. Then, the recording medium P onto which the toner image has been transferred passes through the fixing unit 80, whereby the toner image is fixed onto the recording medium P by the action of heat and pressure, and the recording medium P onto which the toner image has been fixed is discharged outside the image forming apparatus 500 and stacked in the stack section 88.

[0084] On the other hand, the surface of the intermediate transfer belt 14 from which the toner image has been transferred to the recording medium P at the secondary transfer nip is cleaned by a belt cleaning unit 162 to remove any residual toner remaining on the surface. In addition, the surface of the photoconductor 3, from which the toner images of each color have been transferred to the intermediate transfer belt 14 at the primary transfer nip, has residual toner removed by a cleaning device 6, has lubricant applied to it by a lubricant application device 10, and is then de-electrified by a de-electrification lamp.

[0085] 4, the imaging unit 1 of the image forming apparatus 500 includes a photoconductor 3 and, as process means, a charging roller 4, a developing device 5, a cleaning device 6, a lubricant applicator 10, etc., housed in a frame 2. The imaging unit 1 is detachable as a process cartridge from the main body of the image forming apparatus 500. In the image forming apparatus 500, the imaging unit 1 is configured so that the photoconductor 3 and the process means as a process cartridge are replaced as a whole, but the imaging unit 1 may be configured so that the photoconductor 3, the charging roller 4, the developing device 5, the cleaning device 6, and the lubricant applicator 10 are replaced as a unit with new ones.

[0086] (Process cartridge) The process cartridge of the present invention comprises at least an image carrier and cleaning means for removing toner remaining on the image carrier, and may further comprise other means as required. As the cleaning means, the cleaning blade of the present invention is used. The process cartridge is a device (component) that incorporates an image carrier and the cleaning blade of the present invention, and also has at least one of a charging means, an exposure means, a developing means, and a transfer means, and is detachably attached to an image forming apparatus. EXAMPLES

[0087] Examples of the present invention will be described below, but the present invention is not limited to these examples. However, "parts" refers to "parts by mass" unless otherwise specified.

[0088] Example 1 <Elastic material> As the elastic member, a polyurethane elastomer sheet having an average thickness (film thickness), JIS-A hardness, 23°C resilience modulus, and Martens hardness (HM) as follows was produced by centrifugal molding and used. Average thickness: 1.8 mm JIS-A hardness: 70 degrees 23°C resilience modulus: 50% Martens hardness (HM): 1.0 N / mm 2

[0089] <Measurement of JIS-A hardness> The JIS-A hardness of the elastic member was measured at 23°C in accordance with JIS K6253 using a micro rubber hardness meter (MD-1, manufactured by Kobunshi Keiki Co., Ltd.).

[0090] <Measurement of the resilience modulus of the elastic member> The resilience modulus of the elastic member was measured at 23°C in accordance with JIS K6255 using a resilience tester (No. 221, manufactured by Toyo Seiki Seisakusho Co., Ltd.). As the sample, a stack of 2-mm-thick sheets was used so that the thickness was 4 mm or more.

[0091] <Measurement of Martens hardness> The Martens hardness (HM) of the elastic member was measured based on ISO14577 using a nanoindenter (ENT-3100, manufactured by Elionix Inc.). A Berkovich indenter was pressed in at a load of 1,000 μN for 10 seconds, held for 5 seconds, and then pulled out at the same loading rate for 10 seconds. The measurement location was set at a position 20 μm from the tip edge of the sheet after molding that had been cut into a blade shape.

[0092] <Processing into a cleaning blade> The obtained polyurethane elastomer sheet was subjected to post-curing to complete the curing reaction in the urethane sheet and eliminate unreacted substances in the urethane sheet, and conditioning to stabilize the physical properties, and then adhered to a holder and processed into a cleaning blade.

[0093] <Production of the coating layer> A fine particle dispersion was prepared using 4 parts of polytetrafluoroethylene (PTFE) micropowder (TF9201Z, manufactured by 3M, volume average particle diameter 200 nm) as fluorine-based fine particles, 1.9 parts of a ternary copolymer copolymerized in a ratio of VdF:HFP:TFE=80 mol%:10 mol%:10 mol%, 0.1 parts of a perfluoroether-based fluorine oil (PT-53, manufactured by Nicca Chemical, molecular weight 3500), and 94 parts of a fluorine-containing organic solvent 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether: HFE-347 (T3057, manufactured by Tokyo Chemical Industry Co., Ltd.). This preparation was carried out by thoroughly dissolving the terpolymer and fluorinated oil in HFE-347, adding fluorine-based fine particles, and further stirring and mixing to obtain a fine particle dispersion. Next, the cleaning blade was immersed in the microparticle dispersion to a depth of 2 mm from the tip surface of the blade, and pulled up at a pulling speed of 1 mm / s. As shown in Figure 5, the cleaning blade was tilted at about 45° and dried at room temperature for 30 minutes in order to collect the fluorine-based microparticles made of PTFE at the blade tip 62c (part including the abutment edge) necessary for the cleaning function, thereby producing the cleaning blade of Example 1.

[0094] (Examples 2 to 6, Comparative Examples 1 to 4) Cleaning blades of Examples 2 to 6 and Comparative Examples 1 to 4 were produced in the same manner as in Example 1, except that the conditions in Example 1 were changed to those shown in Table 1. It should be noted that Comparative Example 1 is a cleaning blade that is made of only an elastic member without a coating layer. Comparative Example 2 is a cleaning blade having only spherical fine particles (PMMA, average particle size 1.5 μm) in the coating layer. Comparative Example 3 is a cleaning blade having only oil (silicone oil KF-96-50cs manufactured by Shin-Etsu Chemical Co., Ltd.) in the coating layer. Comparative Example 4 is a cleaning blade produced with reference to Example 1 described in Japanese Patent No. 3201949, in which polyvinylidene fluoride (PVdF) was used as the fluorine-based resin and xylene hexafluoride (HCFC-225) was used as the fluorine-containing organic solvent.

[0095] [Table 1]

[0096] <Assembly of image forming device> The produced cleaning blade was attached to a process cartridge of a color multifunction printer (imagio MP C4500, manufactured by Ricoh Co., Ltd.) (the printer unit has a similar configuration to the image forming apparatus 500 shown in FIG. 3) to assemble the image forming apparatus. The cleaning blade was attached to the image forming apparatus so that the linear pressure was 20 g / cm and the cleaning angle was 79°.

[0097] <Torque rating> Using the above-mentioned imaging device, printing was performed under the following conditions. During printing, the driving torque of the photoconductor was measured. After printing, the tip of the cleaning blade was observed with a laser microscope (LEXT OLS4500, manufactured by Olympus Corporation) and the torque was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 2. In the evaluation criteria, "initial" refers to the 1st sheet to the 500th sheet. Environment: 23℃ / 45%RH Paper feed conditions: Blank chart Output quantity: 5,000 sheets (A4 size landscape) -Evaluation criteria- ⊚: The rate of change in torque increase was within 50% of the initial value, and the photoconductor did not stop due to the increase in drive torque. Furthermore, even after printing, there was no trace of the blade being turned over when observed. ○: The rate of change in torque increase is within 50% of the initial value, and the photoconductor does not stop due to the increase in drive torque. However, when the blade was observed after printing, there were traces of turning, but the level was not so high that the toner was removed, so there is no problem in practical use. ×: The photoconductor stopped due to an increase in torque, and when the blade was observed after printing, there were traces of the blade having been turned up to the extent that the toner had fallen out, which was problematic in practical use.

[0098] <Cleaning evaluation> Using the above image forming apparatus, output was performed under the following conditions. Thereafter, the edge of the cleaning blade and the surface of the photoreceptor were observed with the above laser microscope and evaluated based on the following evaluation criteria. The evaluation results are shown in Table 2. Environment: 27℃ / 80%RH Paper feed conditions: 5% image area ratio chart printed 3 times / job Output quantity: 50,000 sheets (A4 size landscape) -Evaluation criteria- ◎: The toner that has slipped through due to poor cleaning cannot be visually confirmed on the printed paper or on the photoconductor, and no streaks of toner can be confirmed even when observing the photoconductor longitudinally with a microscope. ○: No toner that has slipped through due to poor cleaning is visible on the printed paper or on the photoconductor. ×: Toner that has slipped through due to poor cleaning can be visually confirmed on the printed paper and on the photoconductor.

[0099] [Table 2]

[0100] With regard to Example 1 and Example 2, the ratio of HFP is higher in Example 2 than in Example 1. As the ratio of HFP increases, the hardness decreases, making it softer as a binding component, which works against the torque evaluation, resulting in a ◯ instead of an ⊚. Example 6 was the softest binding component and was rated ◯ for torque, but was rated ⊚ for cleaning because its softness allowed it to more easily follow the movement of the cleaning blade tip and maintain its effectiveness. On the other hand, with regard to the comparative examples, Comparative Example 1 was a cleaning blade made of only a simple elastic member, and since μ was high, it was rated as × in both evaluations. In Comparative Example 2, although fine particles were present, there was no binding component, and therefore the low sliding effect could not be maintained, and therefore both evaluations were rated as ×. In Comparative Example 3, although only silicone oil was present, there was no binding component for the same reason as in Comparative Example 2, and therefore it was rated x in both evaluations. Comparative Example 4 contains PTFE particles and PVdF resin as a binding component, but PVdF is a crystalline resin that cracks and peels off depending on the behavior of the tip of the cleaning blade, making it difficult to maintain the low friction effect, and both evaluations were negative. [Explanation of symbols]

[0101] 1 Imaging unit 2 frame 3Y, 3C, 3M, 3K photoreceptor 3 Image carrier 4. Charging roller 5. Developing device 6 Cleaning device 7 Primary transfer roller 10 Lubricant application device 14 Intermediate transfer belt 40 Optical writing unit 41 Polygon Mirror 51 Developing roller 52 Supply screw 53 Mixing screw 54 Doctor 55 Registration roller pair 60 Transcription Unit 62 Cleaning blade 62a Blade tip surface 62b Underside of blade 62c Contact part 62d coating layer 162 Belt cleaning unit 162a Belt cleaning blade 621 Support member 622 Elastic Members 63 First bracket 64 Second Bracket 66 Secondary transfer backup roller 67 Drive roller 68 Auxiliary roller 69 Tension roller 70 Secondary transfer roller 80 Fuser unit 81 Pressure and heating roller 82 Fixing belt unit 83 Heating Roller 84 Fixing belt 85 Tension roller 86 Drive roller 87 Paper ejection roller pair 88 Stack Section 100 toner cartridges 101 Fur Brush 103 Solid Lubricants 103a Lubricant pressure spring 103b Bracket 151 First paper feed cassette 151a First feed roller 152 Second paper feed cassette 152a Second feed roller 153 Paper feed path 154 Transport roller pair 500 Image forming device L Laser light P Recording medium [Prior art documents] [Patent documents]

[0102] [Patent Document 1] Japanese Patent Application Publication No. 8-220962 [Patent Document 2] JP 2000-147972 A [Patent Document 3] Japanese Patent Application Publication No. 6-348193 [Patent Document 4] JP 2017-16083 A

Claims

1. A cleaning blade having an elastic member 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 elastic member has a coating layer containing fluorine-based fine particles and a binding component containing at least a fluorine-based oil, The cleaning blade has a coating layer formed on at least a part of a contact side where the elastic member and the member to be cleaned come into contact with each other.

2. 2. The cleaning blade according to claim 1, wherein the fluorine-based fine particles include polytetrafluoroethylene (PTFE) fine particles.

3. 3. The cleaning blade according to claim 2, wherein the polytetrafluoroethylene (PTFE) fine particles have a volume average particle size of 1 [mu]m or less.

4. 4. The cleaning blade according to claim 1, wherein the binder component is a fluorine-based oil or a mixture of a fluorine-based oil and a fluorine-based resin.

5. 5. The cleaning blade according to claim 1, wherein the fluorine-based oil has a perfluoroether as a main skeleton and a weight average molecular weight of 2,000 to 3,500.

6. 5. The cleaning blade according to claim 4, wherein the fluorine-based resin is a ternary copolymer of vinylidene fluoride (VdF), hexafluoropropylene (HFP) and tetrafluoroethylene (TFE), ie, VdF-HFP-TFE.

7. 7. The cleaning blade according to claim 6, wherein the VdF-HFP-TFE terpolymer has a composition of VdF / HFP / TFE of 30-85 mol % / 10-35 mol % / 5-35 mol %.

8. 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; 8. A process cartridge, wherein the cleaning means comprises the cleaning blade according to claim 1.

9. the image carrier; charging means for charging the surface of the image carrier; exposure means for exposing the charged image carrier to light to form an electrostatic latent image; developing means for developing the electrostatic latent image into a toner image; transfer means for transferring the toner image to a recording medium; fixing means for fixing the toner image transferred to the recording medium; and cleaning means for contacting the surface of the image carrier to remove residues on the surface of the image carrier; 8. An image forming apparatus, wherein the cleaning means comprises the cleaning blade according to claim 1.

Images