Blade for electrophotography, and image forming apparatus

Abstract

To provide a blade for electrophotography that can maintain a lubricant application function and an image carrier cleaning function over a long period.SOLUTION: A blade for electrophotography comprises an elastic member having a contact surface in contact with a surface of an image carrier. The contact surface is a polyurethane elastomer including a reactant of polytetramethylene ether glycol, aromatic isocyanate, and amine. The Martens hardness of the contact surface is 5.0 N / mm2 or more and 30.0 N / mm2 or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electrophotographic blade and an image forming apparatus. [Background technology]

[0002] Electrophotographic image forming apparatuses are generally equipped with a cleaning device that cleans the surface of the image carrier to remove residual toner remaining on the surface of the image carrier after transfer and to allow the image carrier surface to be used repeatedly for image formation. As such a cleaning device, a device using a cleaning blade made of an elastic material such as polyurethane rubber is generally used because it is simple in structure and has excellent toner removal performance. Also, in order to reduce the coefficient of friction between such a cleaning blade or the like and the surface of the image carrier, an image forming apparatus equipped with a lubricant supplying device that supplies a lubricant such as a fatty acid metal salt to the surface of the image carrier is known. In such an image forming apparatus, if the amount of lubricant supplied to the surface of the image carrier is too small, the coefficient of friction cannot be sufficiently reduced, and problems due to a high coefficient of friction (e.g., curling of the cleaning blade and shortened life of the image carrier) cannot be sufficiently suppressed. On the other hand, if the amount of lubricant supplied to the surface of the image carrier is too large, the amount of lubricant adhering to various members and devices present around the image carrier increases, and problems due to the adhesion of the lubricant (e.g., generation of abnormal images due to the adhesion of the lubricant to a charging member, developer carrier, etc.) become prominent. Therefore, in an image forming apparatus having a configuration for supplying a lubricant to the surface of the image carrier, it is important to control the amount of lubricant supplied to the surface of the image carrier to an appropriate amount.

[0003] Among such image forming devices, there is one that supplies the lubricant to the image carrier surface upstream of the contact point of the cleaning blade in the image carrier surface movement direction. In this configuration, the cleaning blade exerts a function of leveling the lubricant supplied to the image carrier surface by stretching, etc. Therefore, it is possible to level the lubricant supplied to the image carrier surface to some extent without providing a lubricant leveling member for leveling the lubricant separately from the cleaning blade. However, in this configuration, the lubricant enters the contact point of the cleaning blade together with the transfer residual toner, so that the amount of lubricant differs between the area where the transfer residual toner exists and the area where it does not exist, and the lubricant cannot be sufficiently leveled. In this case, there are areas on the image carrier surface where the amount of lubricant is too much or too little, and the above-mentioned problems may occur locally. In addition, in the above configuration, the lubricant adheres to the transfer residual toner and is cleaned together with the toner. In this case, it is difficult to accurately grasp the amount of lubricant that is cleaned, so it becomes difficult to control the supply amount and consumption amount of the lubricant, and as a result, the above-mentioned problems are likely to occur.

[0004] For example, an image forming apparatus has been disclosed in which a lubricant supplying means is provided downstream of the contact point of the cleaning blade in the moving direction of the image carrier surface, and a lubricant leveling blade for leveling the lubricant is provided further downstream. According to such an image forming apparatus, the image carrier surface to which the lubricant is supplied is already cleaned, so the lubricant supplied to the image carrier surface can be sufficiently leveled by the lubricant leveling blade. In addition, since it is possible to prevent the lubricant from adhering to the transfer residual toner and being cleaned together with the toner, it is easy to control the supply amount and consumption amount of the lubricant. The lubricant leveling blade described in Patent Document 1 levels the lubricant supplied to the image carrier surface by contacting the ridge portion with the image carrier surface so that the ridge portion intersects with the surface moving direction of the image carrier surface. This lubricant leveling blade is a right-angle blade, with the blade corners formed by two surfaces that face the image carrier surface on the upstream and downstream sides of the surface movement direction of the image carrier surface, sandwiching a ridge portion that abuts against the image carrier surface, forming a right angle.

[0005] In recent years, image forming apparatuses are required to be maintenance-free for a long period of time, and it is therefore desirable to maintain the functionality of the lubricant leveling blade constant from the beginning over time. In order to maintain the functionality of the lubricant leveling blade, it is necessary to reduce the amount of wear over time at the ridges of the lubricant leveling blade that come into contact with the surface of the image carrier. In Patent Document 2, an obtuse-angle blade is used as a lubricant-leveling blade, in which the blade corner angle formed by two surfaces facing the image carrier surface on the upstream and downstream sides of the surface movement direction of the image carrier surface, sandwiching a ridge portion that abuts against the image carrier surface, is an obtuse angle.

[0006] In image forming apparatuses that are not provided with a lubricant supply mechanism or a lubricant leveling blade, a cleaning blade made of polyurethane rubber having high hardness is generally used so as to minimize friction with the image bearing member.

[0007] Patent Document 3 discloses an electrophotographic blade in which polyurethanes with different hardness are arranged in the edge portion and the backup portion. Summary of the Invention [Problem to be solved by the invention]

[0008] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an electrophotographic blade capable of maintaining its lubricant application function and image carrier cleaning function for a long period of time. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides a method for manufacturing an image carrier comprising the steps of: the abutment surface is a polyurethane elastomer comprising a reaction product of polytetramethylene ether glycol, an aromatic isocyanate, and an amine; The Martens hardness of the contact surface is 5.0N / mm 2 More than 30.0N / mm 2 The following is an electrophotographic blade. Effect of the Invention

[0010] According to the present invention, it is possible to provide an electrophotographic blade capable of maintaining the lubricant application function and the image carrier cleaning function for a long period of time. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic diagram showing an electrophotographic blade according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing a state in which an electrophotographic blade according to an embodiment of the present invention is disposed in contact with an image carrier. [Diagram 3] 1 is a schematic diagram illustrating an image forming apparatus according to an embodiment of the present invention; [Figure 4] 1 is a schematic configuration diagram showing one of the image forming units in an image forming apparatus according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The electrophotographic blade according to the present invention comprises an elastic member having a contact surface that contacts the surface of an image bearing member, the contact surface being made of a polyurethane elastomer containing a reaction product of polytetramethylene ether glycol, an aromatic isocyanate, and an amine, and having a Martens hardness (hereinafter sometimes referred to as "HM") of 5.0 N / mm 2 More than 30.0N / mm 2 The following is the result.

[0013] Conventional lubricant leveling blades with blunt blade corners have certainly achieved a certain level of performance in terms of preventing curling or deformation of the contact area and applying lubricant to the surface of the image carrier, but there is a problem that they are insufficient to meet the increasing speed and high image quality required in recent image forming devices. Furthermore, in the case of a cleaning blade for an electrophotographic system that does not use a lubricant, if it is made of conventional polyurethane rubber, the friction between the image carrier and the cleaning blade increases, and the cleaning blade is pulled in the moving direction of the image carrier, causing the contact portion (tip ridge portion) of the cleaning blade to curl up. Furthermore, if cleaning is continued with the contact portion of the cleaning blade curled up, local wear occurs at a location several μm away from the contact portion on the tip surface of the cleaning blade, and if cleaning is continued in this state, the local wear increases, and ultimately the contact portion breaks off. When the contact portion is chipped in this way, the frictional force increases and causes poor cleaning, and in particular, there is a problem in that external additives (silica, etc.) in the toner are fixed to the image carrier.

[0014] As a result of intensive research by the present inventors, it was decided that the Martens hardness of the contact surface of the elastic member having a contact surface that contacts the surface of the image carrier should be 5.0 N / mm 2 More than 30.0N / mm 2It has been found that by making the hardness as high as 1000 MPa or less, the behavior of the tip edge portion is stabilized and wear of the tip edge portion due to friction with the image carrier can be suppressed. As a result, it has been found that the lubricant-leveling blade can suppress abnormal images caused by uneven application of lubricant in the sub-scanning direction. Furthermore, when used as a cleaning blade, the electrophotographic blade according to the present invention is advantageous in that it is resistant to edge chipping in low temperature environments, which is a common side effect of high hardness blades, and therefore can maintain a high level of cleaning function for a long period of time.

[0015] The above-mentioned features of the electrophotographic blade of the present invention will be described in detail with reference to the following drawings. Fig. 1 is a schematic diagram showing an electrophotographic blade according to one embodiment of the present invention. As shown in Fig. 1, the electrophotographic blade has a flat support member 6013 made of a rigid material such as metal or hard plastic, and a flat elastic member 601. The elastic member 601 is fixed to one end side of the supporting member 6013 . The elastic member 601 can have either a single-layer structure or a laminated structure, and has an edge layer 6011 with a tip ridge portion and a base layer 6012. In this case, the edge layer 6011 and the base layer 6012 are generally made by laminating urethane rubbers having different Martens hardness, and the base layer 6012 is generally made of rubber that is less susceptible to environmental variations in rubber properties and has small permanent deformation, thereby covering up defects of the edge layer.

[0016] 2 is a schematic diagram showing a state in which an electrophotographic blade according to an embodiment of the present invention is disposed in contact with an image carrier 3. As shown in FIG. 2, the electrophotographic blade contacts the surface of the image carrier 3 via a contact portion 602 of an elastic member 601.

[0017] <Image carrier> The image bearing member is not particularly limited in terms of material, shape, structure, size, etc., and may be appropriately selected depending on the purpose. The shape of the image bearing member is not particularly limited and may be appropriately selected depending on the purpose. Examples of the shape include a drum shape, a belt shape, a flat plate shape, and a sheet shape. The size of the image bearing member is not particularly limited and can be appropriately selected depending on the purpose, but a size that is generally used is preferable. The material of the image bearing member is not particularly limited and can be appropriately selected depending on the purpose. Examples of the material include metal, plastic, and ceramic.

[0018] <Elastic material> The elastic member preferably has an edge layer and a base layer. The edge layer has a tip ridge portion (hereinafter, sometimes referred to as a "contact surface") that contacts the image carrier. The tip edge of the elastic member that comes into contact with the image carrier is made of polyurethane elastomer, and its Martens hardness is 5.0 N / mm 2 More than 30.0N / mm 2 The angle (edge ​​angle) of the tip ridge of the elastic member is preferably 90° or more and 140° or less.

[0019] The method for measuring the Martens hardness is not particularly limited and may be appropriately selected depending on the purpose. For example, the Martens hardness may be measured using an ultra-microhardness tester HM-2000 manufactured by Fisher Instruments under the following conditions: a Vickers indenter is pressed into the sample surface with a force of 9.8 mN for 30 seconds, held in that position for 5 seconds, and then removed with a force of 9.8 mN over 30 seconds.

[0020] The elastic member is not particularly limited in shape, size, structure, etc., and may be appropriately selected depending on the purpose. The elastic member may have, for example, a flat plate, a rectangular strip, a sheet, or the like. The size of the elastic member is not particularly limited and can be appropriately selected depending on the size of the image bearing member.

[0021] The polyurethane elastomer of the elastic member is a polyurethane elastomer containing a reaction product of polytetramethylene ether glycol, aromatic isocyanate, and amine. Polytetramethylene ether glycol, aromatic isocyanate, and amine react with each other, and the molecules are bonded to each other by urethane bonds, thereby obtaining a hardened reaction product (hereinafter, sometimes referred to as a "hardened product").

[0022] As a result of extensive investigation, it has been found that polytetramethylene ether glycol (PTMG) can be preferably used as the polyol component of the polyurethane elastomer.

[0023] The number average molecular weight of the polytetramethylene ether glycol is not particularly limited and may be appropriately selected depending on the purpose, but is preferably from 850 to 2000. When the number average molecular weight is from 850 to 2000, the Martens hardness of the polyurethane elastomer is 5.0 N / mm 2 More than 30.0N / mm 2 While having a relatively high value of 0.1 to 100%, it is possible to exert elastic function.

[0024] The method for measuring the number average molecular weight is not particularly limited and can be appropriately selected depending on the purpose. For example, the component dissolved in THF can be measured by GPC under the following conditions. GPC equipment: Tosoh Corporation HLC-8120GPC COLUMN: TSK-GEL manufactured by Tosoh Corporation Solvent: THF Solvent concentration: 0.5% by mass Flow rate: 1.0ml / min

[0025] The urethane prepolymer of the elastic member is not particularly limited and can be appropriately selected. However, as a result of extensive investigation, it has been found that a polyurethane elastomer containing a urea bond obtained by reacting a prepolymer in which the hydroxyl group of a polyol is substituted with a difunctional isocyanate and an aromatic diamine is preferred.

[0026] The bifunctional isocyanate is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include dicyclohexylmethane 4,4'-diisocyanate (hydrogenated MDI), 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. Of these, tolylene diisocyanate (TDI) is preferred.

[0027] The aromatic diamine is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include diethylmethylbenzenediamine, dimethylthiotoluenediamine 4,4'-diaminodiphenyl ether, 2,2'bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, 1,3-bis(4-aminophenoxy)benzene, 4,4'-diaminodiphenyl sulfone, 4,4'-methylene-bis(2-chloroaniline), and trimethylene-bis(4-aminobenzoate). These may be used alone or in combination of two or more. Among these, dimethylthiotoluenediamine is preferred.

[0028] The method for preparing the polyurethane elastomer is not particularly limited and may be appropriately selected depending on the purpose. For example, the polyurethane elastomer may be obtained by preparing a polyurethane prepolymer by substituting a hydroxy group of a polyether polyol with a bifunctional isocyanate, adding an aromatic diamine to the polyurethane prepolymer, and reacting the NCO group of the prepolymer with the amino group of the aromatic diamine, which is a curing agent, to form a urea bond.

[0029] The tan δ peak temperature of the polyurethane elastomer is not particularly limited and may be appropriately selected depending on the purpose, but is preferably from 60° C. to 120° C. When the tan δ peak temperature is from 60° C. to 120° C., the Martens hardness and the friction coefficient are unlikely to change in the temperature range in which the electrophotographic system is used, and the function as an elastic member is stable.

[0030] The method for measuring the tan δ peak temperature is not particularly limited and can be appropriately selected depending on the purpose, but it can be measured at a frequency of 10 Hz using DMS6100 manufactured by Hitachi High-Tech Science.

[0031] The base layer of the elastic member is not particularly limited and may be appropriately selected depending on the purpose, but is preferably made of a polyurethane elastomer since high elasticity can be easily obtained. The polyurethane elastomer of the base layer 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.

[0032] 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. The high molecular weight polyol is a polyol having a molecular weight of 500 or more, and examples thereof include polyester polyols which are condensates of alkylene glycol and aliphatic dibasic acid; polyester polyols such as polyester polyols of alkylene glycol 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.

[0033] The low molecular weight polyol is a polyol having a molecular weight of less than 500, and examples thereof 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.

[0034] 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.

[0035] 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 from 0.01% by mass to 0.5% by mass, and more preferably from 0.05% by mass to 0.3% by mass.

[0036] The Martens hardness of the base layer is not particularly limited and can be appropriately selected depending on the purpose. 2 More than 2.0N / mm 2 The Martens hardness is preferably 0.5 N / mm 2 When the Martens hardness is 2.0 N / mm or more, the hardness of the base layer is appropriate, and cutting and other processes after centrifugal molding are easy. 2 If it is equal to or less than this, the environmental change and permanent deformation of the base layer are small.

[0037] The method for measuring the Martens hardness is not particularly limited and may be appropriately selected depending on the purpose. For example, the Martens hardness may be measured using an ultra-microhardness tester HM-2000 manufactured by Fisher Instruments.

[0038] The base layer 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 Martens hardness are integrally molded, since this can achieve both abrasion resistance and conformability.

[0039] The average thickness of the electrophotographic blade is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 1.0 mm or more and 2.5 mm or less.

[0040] <Supporting member> The shape, size, material, etc. of the support member are not particularly limited and may be appropriately selected depending on the purpose. The shape of the support member is not particularly limited and may be appropriately selected depending on the purpose. Examples of the shape include a flat plate, a strip, and a sheet. The size of the supporting member is not particularly limited and can be appropriately selected depending on the size of the image bearing member. The material of the support member is not particularly limited and may be appropriately selected depending on the purpose, and examples thereof include metal, plastic, ceramic, etc. Among these, metal is preferable from the viewpoint of strength. As the metal, a steel plate such as stainless steel, an aluminum plate, and a phosphor bronze plate are preferable.

[0041] <Lubricant> The lubricant is not particularly limited and may be appropriately selected depending on the purpose, and examples thereof include lamellar crystal powder such as zinc stearate, fatty acid salts, wax, silicone oil, etc. Among these, lamellar crystal powder is preferred.

[0042] The lamellar crystal powder has a layered structure in which amphiphilic molecules are self-organized, and when a shear force is applied, the crystals tend to crack and peel off along the layers. This action is thought to be effective in reducing the friction coefficient. The lamellar crystal powder is not particularly limited and can be appropriately selected depending on the purpose. For example, zinc stearate can be used.

[0043] The fatty acid is not particularly limited and can be appropriately selected depending on the purpose. Examples of the fatty acid include undecylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, pentadecylic acid, stearic acid, heptadecylic acid, arachidic acid, montanic acid, oleic acid, arachidonic acid, caprylic acid, capric acid, and caproic acid. The fatty acid may be a fatty acid metal salt. The metal therefor is not particularly limited and may be appropriately selected depending on the purpose, and examples thereof include zinc, iron, copper, magnesium, aluminum, and calcium.

[0044] (Image forming apparatus and image forming method) The image forming apparatus of the present invention comprises at least an image carrier, a charging means, an exposure means, a visible image forming means, a transfer means, a fixing means, and a removing means, and may further comprise other means appropriately selected as necessary, such as a lubricant leveling means. The charging means and the exposure means may be collectively referred to as an electrostatic latent image forming means. The image forming method used in the present invention includes at least a charging step, an exposure step, a visible image forming step, a transfer step, a fixing step, and a removal step, and further includes other steps appropriately selected as necessary, such as a lubricant leveling means. 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 means, the exposure step can be performed by the exposure means, the visible image forming step can be performed by the visible image forming means, the transfer step can be performed by the transfer means, the fixing step can be performed by the fixing means, the removal step can be performed by the removal means, and the other steps can be performed by the other means.

[0045] The latent 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. A preferred shape is a drum shape, and examples of its material include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors such as polysilane and phthalopolymethine. Examples of the organic photoreceptor include a laminated type 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 type photoreceptor having a single-layer photosensitive layer on a support in which both a charge generation material and a charge transport material are dispersed in a binder resin. In the case of a single-layer type photoreceptor, a hole transport material and an electron transport material can be added as charge transport materials to the photosensitive layer. An undercoat layer may be provided between the support and the multi-layer charge generating layer or the single-layer photosensitive layer.

[0046] <Charging process and charging means> The charging step is a step of charging the surface of the image bearing member, and is carried out by a charging unit. The charging can be carried out, for example, by applying a voltage to the surface of the image bearing member using the charging unit. The charging means is not particularly limited 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 utilizing 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.

[0047] 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 preferable 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.

[0048] <Exposure Step and Exposure Means> The exposure step is a step of exposing the charged surface of the image bearing member to light, and is carried out by the exposure unit. The exposure can be carried out, for example, by exposing the surface of the image bearing member imagewise 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 projects an original directly onto an image carrier by an optical system, while the digital optical system is an optical system that receives image information as an electrical signal, converts it into an optical signal, and exposes an electrophotographic photosensitive member to form an image. The exposure means is not particularly limited as long as it can expose the surface of the image carrier charged by the charging means in the form of an image to be formed, 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.

[0049] <Visible image forming process and visible image forming means> The visible image forming step is a step of developing the electrostatic latent image with the toner to form a visible image. The visible image can be formed, for example, by developing the electrostatic latent image with the toner, and can be formed by the visible image forming unit. The visible image forming means is not particularly limited as long as it can develop an image using the toner, and can be appropriately selected from known visible image forming means. For example, a suitable visible image forming means is one that contains the toner and has at least a developing unit that can apply the toner to the electrostatic latent image in a contact or non-contact manner.

[0050] 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 example is one having an agitator that charges the toner by friction and agitation, 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 a 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 electrical attraction. As a result, the electrostatic latent image is developed by the toner, and a visible image of the toner is formed 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.

[0051] <Transfer process and transfer means> The transfer step is a step in which a transfer device transfers the toner image to a recording medium. An example of the transfer step is an intermediate transfer step. The intermediate transfer step includes a primary transfer step and a secondary transfer step. In the primary transfer step, a plurality of primary transfer means sequentially transfer toner images formed on a plurality of image carriers to an intermediate transfer body, forming a full-color toner image on the intermediate transfer body. In the secondary transfer step, a secondary transfer means transfers the full-color toner image from the intermediate transfer body to a recording medium. The transfer step is not limited to the intermediate transfer step, and may be a direct transfer step. Examples of transfer means including a primary transfer means and a secondary transfer means include a corona discharger, a transfer belt, a transfer roller, and a pressure transfer roller. The recording medium is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include plain paper and OHP sheets.

[0052] <Fixing process and fixing means> In the fixing step, the fixing means fixes the toner transferred to the recording medium onto the recording medium. For example, the fixing means may be a heater, a fixing belt, a pressure roller, etc. The heater heats the fixing belt to a fixing target temperature set within a range of 80°C to 200°C. The pressure roller is pressed toward the fixing belt to form a fixing nip. The recording medium passes through this fixing nip, and heat and pressure are applied to the toner on the recording medium, fixing the toner to the recording medium. There are various types of fixing means that can be used.

[0053] <Removal step and removal means> The removing step is a step of removing the toner remaining on the image bearing member, and can be suitably performed by a removing unit. As the removing means, the cleaning blade of the present invention is used. The elastic member of the cleaning blade is not particularly limited and can be appropriately selected according to the purpose, but it is preferable that the cleaning blade is brought into contact with the surface of the image carrier with a pressing force of 10 N / m or more and 100 N / m or less. When the pressing force is 10 N / m or more, cleaning failure due to toner passing through the contact portion where the elastic member of the cleaning blade contacts the surface of the image carrier is unlikely to occur, and when the pressing force is 100 N / m or less, an increase in the friction force at the contact portion can be suppressed, and the cleaning blade does not roll up. The pressing force is preferably 10 N / m to 50 N / m. The pressing force can be measured, for example, by using a measuring device incorporating a small compression load cell manufactured by Kyowa Electric Industries, Ltd. The angle θ between the tangent line at the point where the elastic member of the cleaning blade contacts the surface of the image carrier and the end face of the cleaning blade is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 65° or more and 85° or less. When the angle θ is 65° or more, the cleaning blade does not curl up, and when the angle is 85° or less, poor cleaning does not occur.

[0054] The lubricant leveling step is a step of applying a lubricant to the surface of the image bearing member and leveling the lubricant, and is performed by a lubricant leveling unit. The lubricant leveling can be performed by molding the lubricant into a solid form, pressing it against the fur brush using a pressure spring, rotating the fur brush to apply the lubricant to the surface of the image bearing member, and then applying the lubricant uniformly with a lubricant leveling blade.

[0055] <Other steps and other means> The other means include, for example, a static elimination means, a recycling means, a control means, and the like. Examples of the other steps include a static elimination step, a recycling step, and a control step.

[0056] -Static charge removal process and static charge removal means- In the charge removing process, a charge removing unit such as a charge removing lamp uniformly reduces the potential of the image carrier. The charge removing unit is not limited to a charge removing lamp, and may be a corona discharger or the like.

[0057] -Recycling process and methods- The recycling step is a step of recycling the toner removed in the removing step to the visible image forming means, and can be suitably carried out by a recycling means. The recycling means is not particularly limited, and examples thereof include known transport means.

[0058] -Control process and control means- The control step is a step of controlling each of the steps, and can be suitably performed 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. For example, the control means includes devices such as a sequencer and a computer.

[0059] 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 image forming apparatus according to an embodiment of the present invention. The 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. A transfer unit 60 equipped with 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 equipped 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.

[0060] 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, 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, the top recording medium P in the second paper feed cassette 152 is discharged toward the paper feed path 153.

[0061] 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. 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.

[0062] FIG. 4 is a schematic diagram showing one of the image forming units in the image forming apparatus according to one embodiment of the present invention. 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.

[0063] Around the photoreceptor 3, a charging roller 4, a developing device 5, a primary transfer roller 7, a cleaning device 6, a lubricant leveling device 10, a static electricity removal lamp, and the like are arranged. The charging roller 4 is a charging member provided in the charging device as a charging means, and the developing device 5 is a visible image forming means that develops an electrostatic latent image formed on the surface of the photoreceptor 3 with toner to form a visible image. The primary transfer roller 7 is a primary transfer member provided in the primary transfer device as a primary transfer means that transfers the toner image on the surface of the photoreceptor 3 to the intermediate transfer belt 14. The cleaning device 6 is a removing means that cleans the toner remaining on the photoreceptor 3 after the toner image is transferred to the intermediate transfer belt 14. The lubricant leveling device 10 is a lubricant leveling means that applies a lubricant to the surface of the photoreceptor 3 after cleaning by the cleaning device 6, and levels the lubricant. The static electricity removal lamp is a static electricity removal means that removes the surface potential of the photoreceptor 3 after cleaning.

[0064] 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. 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.

[0065] The cleaning device 6 includes a fur brush 101 and a cleaning blade 62. The cleaning blade 62 is a cleaning blade of the present invention, and contacts the photoconductor 3 in a counter direction to the surface movement direction of the photoconductor 3. 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.

[0066] 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 to 800 nm.

[0067] 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.

[0068] 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 image.

[0069] 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. 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 solenoid is driven. When forming a monochrome image, the image forming apparatus 500 rotates the first bracket 63 slightly counterclockwise in FIG. 3 by driving the 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 image forming units 1Y, 1C, 1M, and 1K, only the image forming unit 1K for K is driven to form a monochrome image. This makes it possible to avoid wear and tear on the members constituting the image forming unit 1 due to unnecessary driving of the image forming units 1 for Y, C, and M during monochrome image formation.

[0070] 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, 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 place 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.

[0071] A temperature sensor is disposed outside the loop of the fixing belt 84 so as to face the front surface of the fixing belt 84 with a specified 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 supply circuit. The fixing power supply circuit controls the on / off of the power supply 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. 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.

[0072] The recording medium P that has been subjected to the fixing process in this manner is discharged outside the 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 apparatus by the discharge roller pair 87 is stacked in this stack section 88 in order. 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.

[0073] 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 or the like, a predetermined voltage or current is sequentially and at a predetermined timing applied to the charging roller 4 and the developing roller 51. Similarly, a predetermined voltage or current is sequentially and at a predetermined timing applied to the optical writing unit 40 and light sources such as the static electricity removal lamp. In synchronization with this, the photoconductor 3 is rotated in the direction of the arrow in FIG. 3 by a photoconductor drive motor serving as a drive means. 3, 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.

[0074] 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. 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, as the recording medium P onto which the toner image has been transferred passes through the fixing unit 80, 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.

[0075] 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, and after lubricant is applied by a lubricant leveling device 10, the surface is neutralized by a neutralization lamp.

[0076] 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 leveling device 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 application device 10 are replaced as a unit with new ones.

[0077] From the viewpoint of improving image quality, it is preferable to use a polymerized toner produced by a suspension polymerization method, an emulsion polymerization method, or a dispersion polymerization method, which can easily achieve a high circularity and a small particle size, as the toner used in the image forming apparatus 500. Among these, it is preferable to use a polymerized toner having a volume average particle size of 5.5 μm or less from the viewpoint of forming a high resolution image.

[0078] The electrophotographic blade can be manufactured by, for example, a sheet molding method, a direct molding method, or the like.

[0079] The sheet molding method includes the following steps (1) and (2). (1) The reaction liquid composition is cast into a sheet shape and reacted and cured to form a raw sheet, which is then cut into a blade (cutting step). In forming the sheet, a centrifugal molding method is generally used. (2) The blade is attached by adhesion or the like to a support member (such as a metal fitting) for mounting the blade to the image forming apparatus to form a blade unit.

[0080] The direct molding method includes the following steps. A mold having a cavity in the shape of the blade to be molded is provided with a support member (such as a metal fitting) for mounting the blade to an image forming apparatus as necessary, and a reactant liquid composition is poured into the molding cavity to mold a blade or blade unit. EXAMPLES

[0081] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples, "parts" and "%" are "parts by mass" and "% by mass" unless otherwise specified.

[0082] (Base layer creation example 1) A polyurethane elastomer base layer 1 was produced by centrifugal molding using urethane rubber A as a material, and the thickness and Martens hardness measured by the following method were the following values. Film thickness: 0.9mm Martens hardness: 0.60N / mm 2

[0083] -Method of measuring Martens hardness- The Martens hardness was measured using a Fisher Instruments HM-2000 ultra-microhardness tester under the following conditions: a Vickers indenter was pressed into the sample surface with a force of 9.8 mN for 30 seconds, held in that position for 5 seconds, and then removed with a force of 9.8 mN over 30 seconds.

[0084] -How to measure film thickness- The thickness of the base layer was measured at five points on the cross section of the obtained base layer using a VHX-8000 (manufactured by KEYENCE Corporation), and the average value was regarded as the thickness of the base layer.

[0085] (Base layer creation example 2) Base layer 2 was produced in the same manner as in base layer production example 1, except that the material in base layer production example 1 was changed from urethane rubber A to urethane rubber B. The film thickness and Martens hardness were measured in the same manner as in base layer production example 1, and the values ​​were as follows. Film thickness: 0.9mm Martens hardness: 2.00N / mm 2

[0086] (Base layer creation example 3) Base layer 3 was produced in the same manner as in base layer production example 1, except that the material in base layer production example 1 was changed from urethane rubber A to urethane rubber C. The film thickness and Martens hardness were measured in the same manner as in base layer production example 1, and the values ​​were as follows. Film thickness: 0.9mm Martens hardness: 1.50N / mm 2

[0087] (Base layer creation example 4) Base layer 4 was produced in the same manner as in base layer production example 1, except that the material in base layer production example 1 was changed from urethane rubber A to urethane rubber D. The film thickness and Martens hardness were measured in the same manner as in base layer production example 1, and the values ​​were as follows. Film thickness: 0.9mm Martens hardness: 1.00N / mm 2

[0088] (Edge layer creation example 1) An edge layer (contact surface) forming liquid was prepared by adding 10 parts by mass of Ethacure 300 (dimethylthiotoluenediamine: DMTDA) manufactured by Mitsui Fine Chemicals as a curing agent to 100 parts by mass of Takenate L-2360 manufactured by Mitsui Chemicals and stirring the mixture. The edge layer (contact surface) forming liquid was poured onto the surface of the base layer 1 in a centrifugal molding machine maintained at a temperature of 120°C, and an edge layer (contact surface) was formed, producing a two-layer polyurethane elastomer sheet (sheet thickness 1.3 mm) with a surface layer thickness of 0.4 mm. After post-curing, the sheet was processed (including obtuse angle cutting) into a lubricant leveling blade to produce the lubricant leveling blade of Example 1. In addition, the Martens hardness, tan δ peak temperature, and edge angle were measured by the following methods.

[0089] -Method of measuring Martens hardness- The Martens hardness was measured using a Fisher Instruments HM-2000 ultra-microhardness tester under the following conditions: a Vickers indenter was pressed into the sample surface with a force of 9.8 mN for 30 seconds, held in that position for 5 seconds, and then removed with a force of 9.8 mN over 30 seconds.

[0090] -Method for measuring tan δ peak temperature- The tan δ peak temperature was measured using DMA7100 (manufactured by Hitachi High-Tech Science Corporation) under conditions of a tensile mode, a heating rate of 2° C. / min, and a frequency of 10 Hz.

[0091] -How to measure edge angle- The edge angle means the angle of the contact portion 602 shown in FIG. 1, and was measured using a VHX-8000 (manufactured by KEYENCE Corporation).

[0092] <Examples 2 to 5, Comparative Examples 1 to 2> Using the same procedure as in Example 1, lubricant leveling blades for Examples 2 to 5 and Comparative Examples 1 and 2 were produced under the conditions shown in Table 1. The Martens hardness of the edge layer was adjusted by changing the amount of Ethacure 300 added.

[0093] <Comparative Example 3> The edge layer was made of 1,4-butanediol (BD) and trimethylolpropane (TMP) instead of Ethacure 300, resulting in a Martens hardness of 0.80 N / mm 2 A polyurethane elastomer sheet was produced by centrifugal molding. Other than that, the same procedures as in Examples 1 to 5 were carried out.

[0094] <Comparative Example 4> The edge layer is made of Daicel Plaxel 220 instead of Takenate L-2360, and 1,4-butanediol (BD) and trimethylolpropane (TMP) instead of Ethacure 300, and the Martens hardness is 1.0 N / mm 2 A polyurethane elastomer sheet was produced by centrifugal molding. Other than that, the same procedures as in Examples 1 to 5 were carried out.

[0095] <Examples 6 to 10 and Comparative Examples 5 to 6> A cleaning blade was produced in the same manner as in Examples 1 to 5, except that the amount of injected raw material was changed and the thickness was adjusted to 2.0 mm. In the same manner as in Example 1, the Martens hardness and tan δ peak temperature of the edge layer (contact surface) of each cleaning blade were measured.

[0096] <Comparative Example 7> A cleaning blade was produced in the same manner as in Comparative Example 3, except that the amount of injected raw material was changed to adjust the thickness to 2.0 mm.

[0097] <Comparative Example 8> A cleaning blade was produced in the same manner as in Comparative Example 4, except that the amount of injected raw material was changed to adjust the thickness to 2.0 mm.

[0098] The "cleaning performance" and "applicability" were evaluated for each of the lubricant leveling blades of Examples 1 to 5 and Comparative Examples 1 to 4, and the cleaning blades of Examples 6 to 10 and Comparative Examples 5 and 6. The evaluation results are shown in Tables 1 to 4 below.

[0099] <Evaluation of Coatability> The lubricant leveling blades prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were attached to the process cartridge of a color multifunction printer (imagio MP C4500, manufactured by Ricoh Co., Ltd.) (the printer section has the same configuration as the image forming apparatus 500 shown in Figure 4) with a linear pressure of 10 N / m and a cleaning angle of approximately 79°. One million sheets (A4 landscape size) were printed continuously using the evaluation toner in a room temperature environment (23°C / 55% RH, chart with an image area ratio of 5%), and then a halftone image was printed and evaluated for the occurrence of white or black streaks on the image. The black streaks are an image defect that occurs when the lubricant leveling function of the lubricant leveling blade is reduced due to wear at the tip of the lubricant leveling blade, and the white streaks are an image defect that occurs when the lubricant is applied unevenly in the longitudinal direction of the image carrier. Both of these defects occur due to insufficient function of the lubricant leveling blade. [Evaluation Criteria] A: No white or black streaks are observed on the image. ◯: Slight white or black streaks are observed on the image, but are within the acceptable range. Δ: A few white or black streaks are observed on the image, and the number of streaks is large, but within the acceptable range. ×: White or black streaks are observed on the image, and it is not suitable for practical use.

[0100] <Evaluation of cleaning ability> The cleaning blades of Examples 6 to 10 and Comparative Examples 5 and 6 were attached to a color multifunction printer (RICOH IM C6000) with a predetermined tip penetration (linear pressure: 20 N / m) and attachment angle (approximately 79°). The tip penetration is defined as the length from the imaginary position of the cleaning blade tip to the surface of the image carrier when the image carrier is not present. The above-mentioned evaluation toner was loaded into the color multifunction printer (RICOH IM C6000), and a chart (A4 size landscape) with an image area ratio of 0.5% and vertical bands was printed 3 times per job at room temperature (23°C / 55% RH) for a total of 50,000 sheets. After that, an evaluation was made as to whether black streaks occurred on the image. The black streaks occur when the edge of the cleaning blade has minute chips or localized wear, causing toner to partially slip through. [Evaluation Criteria] A: No black streaks are observed on the image. B: Slight black streaks are observed on the image, but are within the acceptable range. △: A few black streaks are observed on the image, and the number of streaks is large, but within the acceptable range. ×: Black streaks were observed on the image, and it was not suitable for practical use.

[0101] [Table 1]

[0102] [Table 2]

[0103] [Table 3]

[0104] [Table 4]

[0105] The aspects of the embodiment of the present invention are as follows, for example. <1> an elastic member having a contact surface that contacts the surface of the image carrier; the abutment surface is a polyurethane elastomer comprising a reaction product of polytetramethylene ether glycol, an aromatic isocyanate, and an amine; The Martens hardness of the contact surface is 5.0N / mm 2 More than 30.0N / mm 2 1. An electrophotographic blade, characterized in that: <2> The tan δ peak temperature of the polyurethane elastomer is 60° C. or higher. <1> 2. An electrophotographic blade according to claim 1 . <3> The elastic member has a laminated structure of at least two layers, that is, an edge layer and a base layer. <1> from <2> 2. The blade for electrophotography according to claim 1 , <4> The angle of the tip edge of the elastic member is 90° or more and 140° or less. <1> from <3> 2. The blade for electrophotography according to claim 1 , <5> the elastic member has a base layer and an edge layer on the base layer, the edge layer having a contact surface that contacts the surface of the image carrier, The base layer has a Martens hardness of 0.5 N / mm 2 More than 2.0N / mm 2 The polyurethane elastomer is <1> from <4> 2. The blade for electrophotography according to claim 1 , <6> An image carrier; a charging means for charging the surface of the image carrier; an electrostatic latent image forming means for forming an electrostatic latent image by exposing the charged image carrier; a visible image forming means for developing the electrostatic latent image with a toner to form a visible image; a transfer means for transferring the visible image onto a recording medium; a fixing means for fixing the transferred image on the recording medium; a removing unit for removing toner remaining on the image carrier, 6. An image forming apparatus, wherein the removing means is the electrophotographic blade according to claim 1. [Explanation of symbols]

[0106] 601 Elastic members 6011 Edge layer 6012 Base layer 6013 Support member 602 Contact part 3 Image carrier 1, 1Y, 1C, 1M, 1K Imaging unit 2 frame 3, 3Y, 3C, 3M, 3K photoreceptor 4. Charging roller 5, 5Y, 5C, 5M, 5K developing device 6 Cleaning device 7, 7Y, 7C, 7M, 7K Primary transfer roller 10 Lubricant leveling 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 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 100Y, 100C, 100M, 100K toner cartridges 101 Fur Brush 103 Solid lubricants 103a Lubricant pressure spring 103b Bracket 104 Lubricant leveling blade 151 First paper feed cassette 151a First paper feed roller 152 Second paper feed cassette 152b Second feed roller 153 Paper feed path 154 Delivery Roller Pair 162 Belt cleaning unit 162a Belt cleaning blade 500 Image forming device L Laser light P Recording medium [Prior art documents] [Patent documents]

[0107] [Patent Document 1] JP 2000-330443 A [Patent Document 2] Patent No. 5505784 [Patent Document 3] Patent No. 5860393

Claims

1. an elastic member having a contact surface that contacts the surface of the image carrier; the abutment surface is a polyurethane elastomer comprising a reaction product of polytetramethylene ether glycol, an aromatic isocyanate, and an amine; The Martens hardness of the contact surface is 5.0 N / mm ２ 30.0N / mm or more ２ 1. An electrophotographic blade, comprising:

2. 2. The electrophotographic blade according to claim 1, wherein the polyurethane elastomer has a tan .delta. peak temperature of 60.degree. C. or higher.

3. 3. The electrophotographic blade according to claim 1, wherein said elastic member has a laminated structure of at least two layers, namely, an edge layer and a base layer.

4. 3. The blade for electrophotography according to claim 1, wherein an angle of a ridgeline of a tip of said elastic member is from 90 degrees to 140 degrees.

5. the elastic member has a base layer and an edge layer on the base layer, the edge layer having a contact surface that contacts the surface of the image carrier, The base layer has a Martens hardness of 0.5 N / mm ２ 2.0N / mm or more ２ 3. The electrophotographic blade according to claim 1, wherein the polyurethane elastomer is one selected from the group consisting of the following polyurethane elastomers:

6. An image carrier; a charging means for charging the surface of the image carrier; an electrostatic latent image forming means for forming an electrostatic latent image by exposing the charged image carrier; a visible image forming means for developing the electrostatic latent image with a toner to form a visible image; a transfer means for transferring the visible image onto a recording medium; A fixing unit for fixing the transferred image on the recording medium; a removing unit for removing toner remaining on the image carrier, 6. An image forming apparatus, wherein said removing means is an electrophotographic blade as defined in claim 1.

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