Protective layer forming device and image forming apparatus

Abstract

To provide a protective layer forming device capable of forming an image carrier protective layer which has both a protective property of an image carrier for a long period and a cleaning property.SOLUTION: A protective layer forming device uses a lubricant applying blade contacting an image carrier surface to apply lubricant onto the image carrier surface, and forms an image carrier protective layer. The lubricant is fatty acid metal salt. A contact surface facing the image carrier of the lubricant applying blade consists of a polyurethane elastomer containing a reaction product composed of polytetramethylene ether glycol, aromatic isocyanate and amine. Martens hardness of the contact surface is between 5.0 N / mm2 and 30.0 N / mm2. The fatty acid metal salt is applied onto the image carrier surface so that standardized ionic strength A of an amount of metal ions originated in fatty acid metal salt satisfies the following expression (1) in a time of flight secondary ion mass spectrometer: 1E-4<A<20E-4 (1).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a protective layer forming apparatus and an image forming apparatus. [Background technology]

[0002] Conventionally, electrophotographic images are formed by forming an electrostatic latent image on an image carrier using electrostatic charges, then forming a visible image by attaching charged toner to the electrostatic latent image using a developing means, and then transferring this visible image onto a recording medium.

[0003] After transferring the visible image onto the recording medium, untransferred toner may remain on the image carrier. If an electrostatic latent image is formed with toner remaining on the image carrier, uniform charging of the image carrier may be hindered. For this reason, after transfer, the toner remaining on the image carrier is removed in a cleaning process before charging. In addition, to prevent toner from remaining on the image carrier after transfer, an image carrier protective agent containing a fatty acid metal salt and an inorganic lubricant such as boron nitride is applied to the surface of the image carrier.

[0004] However, the stress caused by friction between the image carrier and the cleaning means in the cleaning process wears the image carrier, causing scratches on the image carrier, and filming on the image carrier cannot be prevented, resulting in poor protection of the image carrier.Furthermore, contamination of the charging means occurs, and furthermore, it is not possible to sufficiently prevent toner from slipping through during the cleaning process.

[0005] Therefore, an image carrier protecting agent has been proposed that contains a fatty acid metal salt and boron nitride, in which the boron nitride has a crystal particle size of 0.1 μm to 1.0 μm and a secondary particle size of 3.0 μm to 14.0 μm (see, for example, Patent Document 1). Also proposed is an image-bearing member protecting agent that contains a fatty acid metal salt and boron nitride, in which the oxygen content of the boron nitride is 0.4% by mass to 4.5% by mass (see, for example, Patent Document 2). Furthermore, a protective layer forming device has been proposed that includes a protective agent block containing a fatty acid metal salt, a core material, and a roller-shaped image carrier protective agent supplying member (see, for example, Patent Document 3). Summary of the Invention [Problem to be solved by the invention]

[0006] However, the use of such protective agents not only consumes a large amount of the protective agent, but also causes significant wear on the cleaning blade, which serves as the cleaning means, and the application blade, which applies the protective agent to the image carrier, resulting in increased frequency of maintenance such as replacement of the protective agent and blade, and also has a negative impact on environmental protection due to increased waste.

[0007] SUMMARY OF THE INVENTION An object of the present invention is to provide a protective layer forming apparatus for forming a protective layer for an image carrier, which has both long-term protection and cleanability for the image carrier. [Means for solving the problem]

[0008] The protective layer forming apparatus of the present invention, which is a means for solving the above problems, has the following configuration. A protective layer forming device for forming an image carrier protective layer by applying a lubricant to the surface of the image carrier using a lubricant application blade that contacts the surface of the image carrier, the lubricant is a fatty acid metal salt, a contact surface of the lubricant application blade that contacts the image bearing member is made of a polyurethane elastomer containing 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 More than 30.0N / mm 2 is as follows: The fatty acid metal salt is applied to the surface of the image bearing member so that the normalized ion intensity A of the amount of metal ions derived from the fatty acid metal salt, as measured by a time-of-flight secondary ion mass spectrometer, satisfies the following formula (1): A protective layer forming apparatus characterized by: 1E -4<A<20E -4 (1)

[0009] The amount of ions formed by the protective layer forming device for an image carrier is measured using a time-of-flight secondary ion mass spectrometer (TOF-SIMS) when sputtering is performed from the outermost surface of the image carrier to the image carrier layer in the depth direction, and the amount of metal ions derived from the fatty acid metal salt is divided by the total amount of ions to form a normalized ion intensity A.

[0010] The application blade is provided with an elastic member having a contact surface that contacts the surface of the image bearing member, and the contact surface is made of a polyurethane elastomer containing a reaction product of polytetramethylene ether glycol, an aromatic isocyanate, and an amine, and has a Martens hardness of 5.0 N / mm 2 More than 30.0N / mm 2 The following is the result. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a protective layer forming apparatus capable of forming an image carrier protective layer that has both long-term protection and cleanability for the image carrier. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a schematic diagram showing a lubricant application blade according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram illustrating a state in which a protective agent application blade according to an embodiment of the present invention is disposed in contact with an image carrier. [Figure 3] 1 is a schematic diagram illustrating the configuration of 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 INVENTION

[0013] The lubricant application blade in the protective layer forming device of the present invention is provided with an elastic member having a contact surface that contacts the surface of the image bearing member, and the contact surface is made of a polyurethane elastomer containing a reaction product of polytetramethylene ether glycol, an aromatic isocyanate, and an amine, and has 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.

[0014] Conventional lubricant application blades with blunted blade corners have certainly achieved a certain level of performance in preventing curling or deformation of the contact area and applying lubricant to the surface of the image carrier, but they have had the problem of being insufficient to meet the increasing speed and high image quality required in recent image forming devices.

[0015] Furthermore, in electrophotographic systems that do not use lubricants, cleaning blades made of conventional polyurethane rubber have the problem that the friction between the image carrier and the cleaning blade increases, causing the cleaning blade to be pulled in the direction of movement of the image carrier, resulting in the cleaning blade's contact portion (tip ridge portion) being curled up. Furthermore, if cleaning is continued with the contact portion of the cleaning blade curled up, local wear occurs at a location on the tip surface of the cleaning blade several μm away from the contact portion, and if cleaning is continued in this state, the local wear increases, eventually causing the contact portion to break off. When the contact portion is chipped off in this way, the frictional force increases further, causing poor cleaning, and in particular, there is a problem that external additives (silica, etc.) in the toner adhere to the image carrier.

[0016] Therefore, as a result of intensive research by the present inventors, it was found that the Martens hardness of the contact surface of the elastic member having a contact surface that contacts the surface of the image carrier is 5.0 N / mm 2 More than 30.0N / mm 2It was found that by making the hardness as high as or less, the behavior of the tip ridge line can be stabilized and furthermore, the tip ridge line can be prevented from wearing down due to friction with the image carrier, and as a result, the lubricant application blade can prevent abnormal images caused by uneven application of lubricant in the sub-scanning direction.

[0017] The features of the lubricant application blade of the present invention will be described in detail with reference to the drawings. Fig. 1 is a schematic diagram showing a lubricant application blade according to one embodiment of the present invention. As shown in Fig. 1, the lubricant application 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 of the support member 6013 . The elastic member 601 can have either a single-layer structure or a laminated structure. Fig. 1 shows an elastic member 601 having a laminated structure. The elastic member 601 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 typically made by laminating urethane rubbers with different Martens hardnesses, and the base layer 6012 is typically made of rubber with small environmental variations in rubber properties and small permanent deformation, thereby covering up any shortcomings of the edge layer.

[0018] 2 is a schematic diagram showing a state in which a lubricant application blade according to an embodiment of the present invention is disposed in contact with an image carrier 3. As shown in FIG. 2, the lubricant application blade contacts the surface of the image carrier 3 via a contact surface 602 of an elastic member 601. 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 photosensitive member 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 fur brush 101, which rotates in the same direction as the rotation of the photosensitive member 3, scrapes off the solid lubricant 103, and the lubricant is applied onto the photosensitive member 3.

[0019] <Elastic material> The elastic member preferably has an edge layer and a base layer. The edge layer has a tip edge portion (hereinafter, sometimes referred to as a "contact surface") that contacts the image carrier. The edge of the elastic member that contacts 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 following is the result.

[0020] The method for measuring the Martens hardness is not particularly limited and can be appropriately selected depending on the purpose. For example, the Martens hardness can 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 place for 5 seconds, and then removed with a force of 9.8 mN over 30 seconds.

[0021] The shape, size, structure, etc. of the elastic member are not particularly limited and can be appropriately selected depending on the purpose. The elastic member may have, for example, a flat plate, a strip, or a sheet shape. The size of the elastic member is not particularly limited and can be appropriately selected depending on the size of the image bearing member.

[0022] The polyurethane elastomer of the elastic member is preferably a polyurethane elastomer containing a reaction product of polytetramethylene ether glycol, aromatic isocyanate, and amine. The polytetramethylene ether glycol, aromatic isocyanate, and amine react to bond the molecules together through urethane bonds, resulting in a cured reaction product (hereinafter sometimes referred to as a "cured product").

[0023] 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.

[0024] The number average molecular weight of the polytetramethylene ether glycol is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 850 or more and 2000 or less. When the number average molecular weight is 850 or more and 2000 or less, 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% or less, it is possible to exert elastic function.

[0025] 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 soluble in THF can be measured by GPC under the conditions shown below. 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

[0026] The urethane prepolymer for the elastic member is not particularly limited and can be selected as appropriate. However, as a result of extensive investigation, it has been found that a polyurethane elastomer containing urea bonds formed by the reaction of a prepolymer in which the hydroxyl groups of a polyol are substituted with a bifunctional isocyanate and an aromatic diamine is preferred.

[0027] The bifunctional isocyanate is not particularly limited and can be appropriately selected depending on 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), tetramethylxylene 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. Among these, tolylene diisocyanate (TDI) is preferred.

[0028] The aromatic diamine is not particularly limited and can be appropriately selected depending on the purpose. Examples 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.

[0029] The method for preparing the polyurethane elastomer is not particularly limited and can be appropriately selected depending on the purpose. For example, the polyurethane elastomer can be obtained by preparing a polyurethane prepolymer by substituting the hydroxy groups of a polyether polyol with a bifunctional isocyanate, adding an aromatic diamine to the polyurethane prepolymer, and reacting the NCO groups of the prepolymer with the amino groups of the aromatic diamine, which is a curing agent, to form urea bonds.

[0030] The base layer of the elastic member is not particularly limited and can be appropriately selected depending on the purpose, but polyurethane elastomer is preferred because it is easy to obtain high elasticity. 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 prepolymer in a predetermined 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 flat plate of predetermined dimensions.

[0031] The polyol compound is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof 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 glycols and aliphatic dibasic acids; polyester polyols such as polyester polyols of alkylene glycols and adipic acid, such as ethylene adipate ester polyol, butylene adipate ester polyol, hexylene adipate ester polyol, ethylene propylene adipate ester polyol, ethylene butylene adipate ester polyol, and ethylene neopentylene adipate ester polyol; polycaprolactone polyols such as polycaprolactone ester polyol obtained by ring-opening polymerization of caprolactone; and polyether polyols such as poly(oxytetramethylene) glycol and poly(oxypropylene) glycol. These may be used alone or in combination of two or more.

[0032] 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.

[0033] 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.

[0034] The curing catalyst is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof 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 or more and 0.5% by mass or less, and more preferably 0.05% by mass or more and 0.3% by mass or less.

[0035] 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 or less. 2 When the Martens hardness is 2.0 N / mm or more, the hardness of the base layer is appropriate, and cutting processing after centrifugal molding is easy. 2 If it is less than this, the environmental fluctuation and permanent distortion of the base layer are reduced.

[0036] The method for measuring the Martens hardness is not particularly limited and can be appropriately selected depending on the purpose. For example, the Martens hardness can be measured using an ultra-microhardness tester HM-2000 manufactured by Fisher Instruments.

[0037] The base layer is not particularly limited and can be selected appropriately depending on the purpose, but it is preferable to use a laminate in which two or more types of rubber with different Martens hardnesses are integrally molded, as this can achieve both abrasion resistance and conformability.

[0038] The average thickness of the lubricant application blade is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1.0 mm or more and 2.5 mm or less.

[0039] The angle (edge ​​angle) of the ridgeline at the tip of the lubricant application blade is preferably 90° or more and 140° or less.

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

[0041] <Lubricant as an image carrier protecting agent> In addition to the fatty acid metal salt, other lubricants may be appropriately selected and used depending on the purpose, such as wax and silicone oil.

[0042] It is preferable to use a lamellar crystal powder as the fatty acid metal salt. The lamellar crystal powder has a layered structure in which amphiphilic molecules are self-assembled, and when shear force is applied, the crystals break along the interlayers, making the powder slippery. This effect is thought to be effective in reducing the coefficient of friction. The lamellar crystal powder is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include zinc stearate.

[0043] The fatty acid is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof 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 metal in the fatty acid metal salt is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include zinc, iron, copper, magnesium, aluminum, and calcium.

[0044] The fatty acid metal salt is applied to the surface of the image carrier so that the normalized ion intensity A of the amount of metal ions derived from the fatty acid metal salt, as measured by a time-of-flight secondary ion mass spectrometer, satisfies the following formula (1): 1E -4 <A<20E -4 (1) In addition, the above "1E-4 <A<20E -4 " is "1 x 10 -4 <A<20×10 -4 " means. Ionic strength A is 1E ―4 From 20E ―4 It is preferable that the range is 1E -4 From 10E ―4 The range is 100%. If the amount is too small, the image carrier will not be adequately protected, resulting in early wear and scratches. Conversely, if the amount is too large, white streaks known as "blur" will likely occur in high humidity environments such as those with temperatures of 28°C and humidity levels of 85% or higher. Blur is said to occur when nitrogen oxides (NOX) generated by the image carrier's charger (charging roller, scorotron charger, etc.) are absorbed into the protective layer, preventing the image carrier from being properly charged. The thicker the protective layer, the higher the risk of blur. Furthermore, if the difference in the longitudinal direction is greater than 50%, white streak images similarly occur due to the protective layer.

[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, 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 protective layer forming means, etc. 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 may further include other appropriately selected steps such as a protective layer forming means, etc. 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 carried out by the charging means, the exposure step can be carried out by the exposure means, the visible image forming step can be carried out by the visible image forming means, the transfer step can be carried out by the transfer means, the fixing step can be carried out by the fixing means, the removal step can be carried out by the removal means, and the other steps can be carried out by the other means.

[0046] <Image carrier> The image carrier (hereinafter, sometimes referred to as "electrophotographic photoreceptor" or "photoreceptor") is not particularly limited in terms of material, shape, structure, size, etc., and can be appropriately selected from known ones. A preferred shape is a drum, and examples of the 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 photoreceptor having a laminated structure in which a layer (charge generation layer) in which a charge generation material such as metal-free phthalocyanine or titanyl phthalocyanine is dispersed in a binder resin and a layer (charge transport layer) in which a charge transport material is dispersed in a binder resin are stacked on a support such as an aluminum drum, and a single-layer photoreceptor having a single-layer photosensitive layer in which both a charge generation material and a charge transport material are dispersed in a binder resin on a support. In the single-layer type photoreceptor, a hole transport material and an electron transport material can be added to the photosensitive layer as charge transport materials. An undercoat layer may be provided between the support and the multilayer charge generating layer or the single-layer photosensitive layer.

[0047] <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 means. The charging means is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a known contact charger equipped with 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 charging means may take any form, such as a roller, a magnetic brush, or a fur brush, and can be selected according to the specifications and configuration 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 particles and a magnet roll enclosed within the sleeve. When a brush is used, the fur brush may be made of fur treated with conductive materials such as carbon, copper sulfide, metal, or metal oxide, and the fur brush may be wound or attached to a metal or other conductive core to form a charger.

[0048] The charger is not limited to the contact type charger described above, but there is an advantage in 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 out of 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 it with a gap tape, and that the surface of the image carrier is charged by applying DC and AC voltages superimposed on the charging roller.

[0049] <Exposure process 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 systems used in the exposure are broadly divided into analog optical systems and digital optical systems. The analog optical systems project an original directly onto an image carrier, while the digital optical systems receive image information as an electrical signal, convert it into an optical signal, and expose 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 may be employed in which image exposure is performed from the back side of the image carrier.

[0050] <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 by, for example, developing the electrostatic latent image with the toner, and can be performed 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 has at least a developing unit that stores the toner and can apply the toner to the electrostatic latent image in a contact or non-contact manner.

[0051] The developing device may be a dry developing device or a wet developing device, 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 agitation, and a rotatable magnetic roller.

[0052] In the developing unit, for example, the toner and, if necessary, a carrier are mixed and stirred, and the toner becomes charged by friction during this process and is held in a standing state on the surface of a rotating magnet roller, forming a magnetic brush. Because the magnet roller is located near the image carrier, a portion 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 with the toner, and a visible toner image 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.

[0053] Alternatively, a premix development method may be used, in which a premix developer, in which toner and carrier are mixed in advance, is replenished. In the premix development method, the excess carrier in the developing device is discharged as excess developer. This gradually refreshes the developer in the developing device. This can extend the replacement cycle associated with developer deterioration and eliminate the effort required for developer replacement.

[0054] <Transfer process and transfer means> The transfer step is a step of transferring the visible image onto a recording medium. A preferred embodiment is one in which an intermediate transfer body is used, the visible image is primarily transferred onto the intermediate transfer body, and then the visible image is secondarily transferred onto the recording medium. A more preferred embodiment is one in which two or more colors, preferably full-color toner, are used as the toner, and the transfer step includes a primary transfer step in which the visible image is transferred onto the intermediate transfer body to form a composite transfer image, and a secondary transfer step in which the composite transfer image is transferred onto a recording medium.

[0055] The transfer can be performed, for example, by charging the image carrier using a transfer unit, and can be performed by the transfer unit. The transfer unit preferably has a primary transfer unit that transfers the visible image onto an intermediate transfer body to form a composite transfer image, and a secondary transfer unit that transfers the composite transfer image onto a recording medium. The intermediate transfer member is not particularly limited and can be appropriately selected from known transfer members depending on the purpose, and examples thereof include a transfer belt.

[0056] The transfer means (the primary transfer means, the secondary transfer means) preferably has at least a transfer device that peels and charges the visible image formed on the image carrier onto the recording medium. The number of transfer devices may be one or more. Examples of the transfer device include a corona transfer device that uses corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device. The recording medium is typically plain paper, but is not particularly limited as long as it can be used to transfer the unfixed image after development, and can be selected appropriately depending on the purpose. PET base for overhead projectors can also be used.

[0057] <Fixing process and fixing means> The fixing step is a step of fixing the toner image transferred to the recording medium, and can be performed using a fixing device. When two or more colors of toner are used, each color of toner may be fixed as it is transferred to the recording medium, or all colors of toner may be transferred to the recording medium and fixed in a stacked state. The fixing device is not particularly limited, and a thermal fixing method using a known heating and pressurizing device can be used. Examples of the heating and pressurizing device include a combination of a heating roller and a pressure roller, and a combination of a heating roller, a pressure roller, and an endless belt. The heating temperature is not particularly limited and can be selected appropriately depending on the purpose, but a temperature of 80°C to 200°C is preferred. If necessary, a known optical fixing device, for example, may be used together with the fixing device.

[0058] <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 carried out by a removing unit. The removing means may be a cleaning blade. The elastic member of the cleaning blade is not particularly limited and can be appropriately selected depending on the purpose.

[0059] The protective layer forming step is a step of applying a lubricant to the surface of the image bearing member and leveling the lubricant, and is carried out by a protective layer forming unit. The protective layer is formed by pressing the solid lubricant 103 of the lubricant application device 10 against the fur brush 101 using the lubricant pressure spring 103a, rotating the fur brush 101 to apply the lubricant to the surface of the image carrier 3, and then applying the lubricant evenly using the lubricant application blade 104.

[0060] The lubricant application blade is preferably pressed against the image bearing member with a contact linear pressure of 0.5 N / m to 10.0 N / m.

[0061] <Other steps and other means> Examples of the other means include a static elimination means, a recycling means, and a control means. Examples of the other steps include a static elimination step, a recycling step, and a control step.

[0062] -Static removal process and static removal means- The charge removal step is a step of removing electricity by applying a charge removal bias to the image bearing member, and can be suitably performed by a charge removal unit. The charge eliminating means is not particularly limited as long as it can apply a charge eliminating bias to the image bearing member, and can be appropriately selected from known charge eliminating devices, and a suitable example is a charge eliminating lamp.

[0063] -Recycling process and means- 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.

[0064] -Control process and control means- The control step is a step of controlling each of the steps, and can be suitably 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.

[0065] An example of the image forming apparatus of the present invention will now be described with reference to the drawings. 3 is a schematic diagram showing the configuration of an image forming apparatus according to one embodiment of the present invention. Image forming apparatus 500 includes 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 to form 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 each color formed on the surfaces of the photosensitive members 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 an overlapping manner. In this embodiment, an elastic intermediate transfer belt can also be used as the intermediate transfer belt 14. As the elastic intermediate transfer belt, for example, one in which a flexible elastic layer is laminated on a rigid base layer that can provide relatively flexibility can be used. Additionally, a guide member for preventing the intermediate transfer belt 14 from meandering may be provided on the inner peripheral surface of the intermediate transfer belt 14. An optical writing unit 40 is disposed below the four imaging units 1. The optical writing unit 40, which serves as a latent image forming means, emits laser light L based on image information and irradiates the photoconductors 3Y, 3C, 3M, and 3K of the imaging units 1Y, 1C, 1M, and 1K with the laser light L. This forms electrostatic latent images for Y, C, M, and K on the photoconductors 3Y, 3C, 3M, and 3K. The optical writing unit 40 polarizes the laser light L emitted from a light source using a polygon mirror 41, which is driven to rotate by a motor, and irradiates the laser light L onto the photoconductors 3Y, 3C, 3M, and 3K via multiple optical lenses and mirrors. Alternatively, an LED array for optical scanning may be used.

[0066] 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. Each of these paper feed cassettes contains a stack of recording media P, and a first paper feed roller 151a and a second paper feed roller 152a abut against the topmost recording medium P. When the first paper feed roller 151a is driven to rotate counterclockwise in FIG. 3 by a drive unit, the topmost recording medium P in the first paper feed cassette 151 is ejected toward a paper feed path 153, which is arranged 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 drive unit, the topmost recording medium P in the second paper feed cassette 152 is ejected toward the paper feed path 153.

[0067] A plurality of conveying roller pairs 154 are arranged in the paper feed path 153. The recording medium P sent into the paper feed path 153 is sandwiched between the rollers of these conveying roller pairs 154 and conveyed within the paper feed path 153 from the bottom to the top in FIG. A pair of registration rollers 55 is disposed at the downstream end in the conveying direction of the paper feed path 153. The pair of registration rollers 55 temporarily stops the rotation of both rollers as soon as they sandwich the recording medium P fed from the pair of conveying rollers 154 between their rollers. Then, they send the recording medium P toward the secondary transfer nip, which will be described later, at an appropriate timing.

[0068] FIG. 4 is a schematic diagram showing one of the image forming units in an image forming apparatus according to one embodiment of the present invention. 4, the imaging unit 1 includes a drum-shaped photosensitive member 3 as an image carrier. Although the photosensitive member 3 is shown as being drum-shaped, it may also be sheet-shaped or endless belt-shaped.

[0069] Around the photoreceptor 3, there are arranged a charging roller 4, a developing device 5, a primary transfer roller 7, a cleaning device 6, a protective layer forming device 10, a static elimination lamp, etc. The charging roller 4 is a charging member provided in a charging device as 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 a primary transfer device as primary transfer means that transfers the toner image on the surface of the photoreceptor 3 to an intermediate transfer belt 14. The cleaning device 6 is a removal means that cleans off toner remaining on the photoreceptor 3 after the toner image has been transferred to the intermediate transfer belt 14. The protective layer forming device 10 is a protective layer forming means that applies a lubricant to the surface of the photoreceptor 3 after cleaning by the cleaning device 6 and smooths out the lubricant. The static elimination lamp is a static elimination means that eliminates the surface potential of the photoreceptor 3 after cleaning.

[0070] The charging roller 4 is disposed at a predetermined distance from the photoreceptor 3 without contacting it, and charges the photoreceptor 3 to a predetermined polarity and a predetermined potential. The surface of the photoreceptor 3, which 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.

[0071] The developing device 5 has a developing roller 51 as a developer carrier. A developing bias is applied to this developing roller 51 from a power source. A supply screw 52 and an agitating screw 53 are provided inside the casing of the developing device 5, which agitate the developer contained in the casing while transporting it in opposite directions. A doctor 54 is also provided to regulate the developer carried on the developing roller 51. The toner in the developer agitated and transported by the twin 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, where it is regulated by the doctor 54, and the toner adheres to the latent image on the photoconductor 3 in the development area facing the photoconductor 3.

[0072] The cleaning device 6 has a fur brush 101, a cleaning blade 62, etc. The cleaning blade 62 is the cleaning blade of the present invention, and is in contact with the photoreceptor 3 in the counter direction to the direction in which the surface of the photoreceptor 3 moves. The charging device is a non-contact close-contact type in which the charging roller 4 is placed close to the photosensitive member 3, but known configurations such as a corotron, scorotron, or solid-state charger can be used as the charging device. Of these charging methods, the contact charging method or the non-contact close-contact type is particularly desirable, as it has advantages such as high charging efficiency, little ozone generation, and the ability to miniaturize the device.

[0073] The light source for the laser light L of the optical writing unit 40 and the light source for the de-electrification 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 electroluminescent (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 because they have high irradiation energy and emit light with a long wavelength of 600 nm to 800 nm.

[0074] The transfer unit 60 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 stretched across these eight rollers and endlessly moves counterclockwise in FIG. 3 by the rotation of the drive roller 67. The four primary transfer rollers 7Y, 7C, 7M, and 7K sandwich the endlessly moving intermediate transfer belt 14 between themselves and the photoreceptors 3Y, 3C, 3M, and 3K, forming primary transfer nips. A transfer bias of the opposite polarity (e.g., positive) to that of the toner is applied to the back surface (inner peripheral surface of the loop) 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 photoreceptors 3Y, 3C, 3M, and 3K are primarily transferred and superimposed onto the front surface of the intermediate transfer belt 14. 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.

[0075] 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, forming a secondary transfer nip. The registration roller pair 55 described above sends the recording medium P sandwiched between them toward the secondary transfer nip at a timing that synchronizes it 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 due to 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. This, combined with the white color of the recording medium P, forms a full-color toner image.

[0076] 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 the belt cleaning unit 162. The belt cleaning unit 162 abuts against the front surface of the intermediate transfer belt 14, thereby scraping off and removing the residual toner on the intermediate transfer belt 14. It is also possible to provide a collecting means for receiving the toner and the like removed by the belt cleaning unit 162. A dish-shaped tray or the like can be used as the collecting means.

[0077] The first bracket 63 of the transfer unit 60 swings at a predetermined rotation angle around the rotation axis of the auxiliary roller 68 as the solenoid is turned on and off. When forming a monochrome image, the image forming apparatus 500 slightly rotates the first bracket 63 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 counterclockwise in FIG. 3 around the rotation axis of the auxiliary roller 68, 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 prevents wear on the components of the imaging unit 1 due to unnecessary driving of the imaging units 1 for Y, C, and M during monochrome image formation.

[0078] A fixing unit 80 is disposed above the secondary transfer nip in FIG. 3. The fixing unit 80 includes a pressure / heat roller 81 incorporating 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 incorporating a heat source such as a halogen lamp, a tension roller 85, a drive 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 drive roller 86 and moves counterclockwise in FIG. 3. During this endless movement, the fixing belt 84 is heated from its backside by the heating roller 83. The pressure / heat roller 81, which rotates clockwise in FIG. 3, contacts the front side of the heated fixing belt 84 at the location where it is wrapped around the heating roller 83. This forms a fixing nip where the pressure / heat roller 81 and the fixing belt 84 come into contact.

[0079] 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 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 supply circuit. Based on the detection result from the temperature sensor, the fixing power supply circuit controls the on / off of power supply to the heat source contained in the heating roller 83 and the heat source contained in the pressure heating roller 81. After passing through the secondary transfer nip, the recording medium P 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.

[0080] The recording medium P that has been subjected to the fixing process in this way is discharged outside the apparatus after passing between the rollers of the discharge roller pair 87. A stack section 88 is formed on the top surface of the housing of the main body of the image forming apparatus 500, and the recording medium P that has been 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 supplied as needed to the developing devices 5Y, 5C, 5M, and 5K of the imaging 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 imaging 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 or the like, a predetermined voltage or current is applied sequentially and at a predetermined timing to the charging roller 4 and the developing roller 51. Similarly, a predetermined voltage or current is applied sequentially and at a predetermined timing to the optical writing unit 40 and the light source such as the static elimination 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.

[0082] 3, the surface of the photoreceptor 3 is first uniformly charged to a predetermined potential by the charging roller 4. Then, a laser beam L corresponding to image information is irradiated onto the photoreceptor 3 from the optical writing unit 40, and the portion of the surface of the photoreceptor 3 irradiated with the laser beam L is neutralized, forming 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 toward the electrostatic latent image 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 toner images of each color are formed on the surfaces of the photoconductors 3Y, 3C, 3M, and 3K of the imaging units 1Y, 1C, 1M, and 1K.

[0083] In this way, in the image forming apparatus 500, the electrostatic latent image formed on the photosensitive member 3 is reverse-developed with negatively charged toner by the developing device 5. In this 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 photoreceptor 3Y, 3C, 3M, and 3K are sequentially transferred (primary transfer) 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 a recording medium P, which is fed from a first paper feed cassette 151 or a second paper feed cassette 152, passes between the rollers of a pair of registration rollers 55, and is fed to the secondary transfer nip. At this time, the recording medium P stops temporarily while sandwiched between the pair of registration rollers 55, and is then 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 with the transferred toner image is separated from the intermediate transfer belt 14 and transported to a fixing unit 80. Then, as the recording medium P with the transferred toner image 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 with the fixed toner image is ejected to the outside of the image forming apparatus 500 and stacked in a stacking unit 88.

[0084] On the other hand, the surface of the intermediate transfer belt 14 from which the toner image has been transferred onto 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 photosensitive member 3, which has transferred the toner images of each color to the intermediate transfer belt 14 at the primary transfer nip, has residual toner removed by a cleaning device 6 after transfer, and after a lubricant is applied by a protective layer forming device 10, it is de-electrified by a de-electrification lamp.

[0085] 4, the imaging unit 1 of the image forming apparatus 500 includes a photosensitive member 3 and, as process means, a charging roller 4, a developing device 5, a cleaning device 6, a protective layer forming device 10, and the like, 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 photosensitive member 3 and the process means as a process cartridge are replaced as a whole, but the imaging unit 1 may also be configured so that each of the photosensitive member 3, charging roller 4, developing device 5, cleaning device 6, and lubricant applying device 10 can be replaced with a new one.

[0086] From the viewpoint of improving image quality, it is preferable to use polymerized toner produced by suspension polymerization, emulsion polymerization, or dispersion polymerization, which can easily achieve high circularity and small particle size, as the toner used in the image forming apparatus 500. Among these, it is preferable to use polymerized toner having a volume average particle size of 5.5 μm or less from the viewpoint of forming high-resolution images.

[0087] The lubricant application blade can be produced by, for example, a sheet molding method, a direct molding method, or the like.

[0088] The sheet forming method includes the following steps (1) and (2). (1) The reaction stock solution 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 sheet formation, a centrifugal molding method is generally used. (2) The blade is attached to a support member (such as a metal fitting) for mounting on the image forming apparatus by adhesive or the like to form a blade unit.

[0089] 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 on an image forming apparatus as needed, and the reactant liquid composition is poured into the molding cavity to mold a blade or blade unit. [Example]

[0090] The present invention will be explained in more detail below by showing examples and comparative examples of lubricant application blades, but the present invention is not limited to these examples. In the examples, "parts" and "%" mean "parts by mass" and "% by mass" unless otherwise specified.

[0091] [Example 1] (Base layer production example 1) To 100 parts of Mitsui Chemicals' Takenate L-2390, 16 parts by weight of Hodogaya Chemical's PTG650SN as a curing agent and 3 parts of Kishida Chemical's trimethylolpropane were added and stirred to prepare a base layer forming liquid, which was then placed in a centrifugal molding machine maintained at a temperature of 120°C to produce a [base layer 1] made of urethane rubber A with the following film thickness and Martens hardness values ​​measured by the following method. Film thickness: 0.9 mm Martens hardness: 0.6N / mm 2

[0092] -Method for measuring Martens hardness- 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 for 5 seconds, and then removed with a force of 9.8 mN over 30 seconds.

[0093] -Method for measuring 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 taken as the thickness of the base layer.

[0094] (Edge layer production example 1) An edge layer (contact surface) forming liquid was prepared by adding 10 parts of Mitsui Chemicals' Takenate L-2390 (manufactured by Mitsui Chemicals) Ethacure 300 (dimethylthiotoluenediamine: DMTDA) as a curing agent to 100 parts of Mitsui Chemicals' Takenate L-2390 and stirring the mixture. The edge layer (contact surface) forming liquid was poured onto the surface of base layer 1 in a centrifugal molding machine maintained at a temperature of 120°C, forming [edge layer 1] (contact surface), and a two-layer polyurethane elastomer sheet (sheet thickness 1.3 mm) with a surface layer thickness of 0.4 mm was produced. After post-curing, the sheet was processed (including obtuse angle cutting) into a lubricant application blade to produce [lubricant application blade 1]. In addition, the Martens hardness and edge angle were measured by the following methods.

[0095] -Method for measuring Martens hardness- 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 for 5 seconds, and then removed with a force of 9.8 mN over 30 seconds.

[0096] -Method for measuring edge angle- The edge angle refers to the angle θ shown in FIG. 1, and was measured using a VHX-8000 (manufactured by KEYENCE Corporation).

[0097] <Evaluation of ionic strength A of protective layer> The lubricant application blade 1 obtained above was attached to a 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) so ​​that the linear pressure was 0.5 N / m to 10 N / m. The lubricant application device used had the structure shown in FIG. 2, and the fatty acid metal salt used was a mixture of zinc stearate and zinc palmitate. One million sheets (A4 size landscape) were continuously printed using the evaluation toner in a room temperature environment (23°C / 55% RH, chart with an image area ratio of 5%), and the total amount of the surface protection layer of the image carrier was then evaluated as follows: That is, the amount of ions when sputtered from the outermost surface of the image carrier to the image carrier layer in the depth direction under the following conditions was measured using a time-of-flight secondary ion mass spectrometer (TOF-SIMS manufactured by IONTOF Inc.), and the normalized ion intensity A was calculated by dividing the amount of metal ions derived from the fatty acid metal salt by the total amount of ions. Ion measurement conditions Ion Gun: Bi3++ Acceleration voltage: 30 kV ·Charge neutralization: On ·Polarity: Posi Raster: 300μm Sputtering conditions Ion gun: Ar-GCIB Acceleration voltage: 5kv Raster: 1000μm Number of scans: 64

[0098] <Evaluation of Coatability> The lubricant application blade 1 was attached to a 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) so ​​that the linear pressure was 0.5 N / m to 10 N / m. One million sheets (A4 size landscape) 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 image defects that occur when the protective layer forming function of the lubricant application blade is reduced due to wear at the tip, etc., of the lubricant application blade, and the white streaks are image defects that occur when the lubricant is applied unevenly in the longitudinal direction of the image carrier. Both of these are caused by insufficient function of the lubricant application blade. [Evaluation criteria] ⊚: No white or black streaks are observed on the image. ◯: A slight amount of white or black streaks are observed on the image, but are within the acceptable range. △: 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.

[0099] <Evaluation of cleaning ability> The produced [lubricant application blade 1] was attached to a color multifunction printer (RICOH IM C6000) so that the line pressure was 0.5 N / m to 10 N / m. The color multifunction printer (RICOH IM C6000) was loaded with the above-mentioned toner for evaluation, and a chart (A4 size landscape) with an image area ratio of 0.5% and vertical bands was printed 3 times per job, for a total of 50,000 sheets, in a room temperature environment (23°C / 55%RH). After that, an evaluation was made to see whether black streaks had occurred on the images. [Evaluation criteria] ⊚: No black streaks are visible on the image. ◯: A slight black streak is observed on the image, but is 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 are observed on the image, and it is not suitable for practical use.

[0100] [Examples 2 to 5, Comparative Examples 1 and 2] (Base layer production examples 2 to 4) In base layer production example 1, [Base layer 2] to [Base layer 4] were produced in the same manner as in production example 1 of [Base layer 1], except that the material urethane rubber A was changed to urethane rubbers B to D with different curing agent addition ratios. In addition, the thickness and Martens hardness of [Base Layer 2] to [Base Layer 4] were measured in the same manner as [Base Layer 1]. The measurement results are shown in Table 1.

[0101] Using the same procedure as in the preparation of [Lubricant Application Blade 1] in Example 1, [Lubricant Application Blade 2] to [Lubricant Application Blade 7] were prepared by forming [Edge Layer 2] to [Edge Layer 7] on the surface of the base layer under the conditions listed in Table 1. The Martens hardness of the edge layer was adjusted by changing the amount of Ethacure 300 added. [Lubricant application blade 2] to [Lubricant application blade 7] were used to form protective layer forming devices for Examples 2 to 5 and Comparative Examples 1 and 2, and evaluations similar to those in Example 1 were carried out.

[0102] <Comparative Example 3> 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, resulting in a Martens hardness of 1.0 N / mm 2 A [lubricant application blade 8] was prepared under the conditions shown in Table 1 in the same manner as in Example 1, except that a polyurethane elastomer sheet was formed on the surface of the base layer 1 by centrifugal molding. The [lubricant application blade 8] was used as the protective layer forming device of Comparative Example 3, and evaluations were carried out in the same manner as in Example 1.

[0103] The lubricant application blades of Examples 2 to 5 and Comparative Examples 1 to 3 were evaluated for "normalized ionic strength A of protective layer," "cleaning ability," and "application ability" in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0104] [Table 1]

[0105] In Comparative Example 1, the Martens hardness of the edge layer was low, so the protective layer was formed non-uniformly in the longitudinal direction, which appeared as white streaks on the image. In Comparative Example 2, the Martens hardness of the edge layer was too high, causing the edge to wear early, resulting in areas where the protective layer could not be applied, which hindered toner cleaning and resulted in black streaks appearing on the image. In Comparative Example 3, the Martens hardness of the edge layer was forcibly increased by using polyol as the curing agent, which caused the edge of the lubricant application blade to chip early, resulting in areas where the protective layer could not be applied, which interfered with toner cleaning and appeared as black and white streaks on the image.

[0106] Based on these results, it is concluded that the lubricant application blade for forming a thin and uniform protective layer on the image carrier has a contact surface made of polyurethane elastomer containing a reaction product of polytetramethylene ether glycol, aromatic isocyanate, and amine, and has a Martens hardness of 5.0 N / mm 2 More than 30.0N / mm 2 It turns out that the following is necessary:

[0107] For example, embodiments of the present invention are as follows. (1) A protective layer forming device for forming a protective layer on an image carrier by applying a lubricant to the surface of the image carrier using a lubricant application blade that contacts the surface of the image carrier, the lubricant is a fatty acid metal salt, a contact surface of the lubricant application blade that contacts the image bearing member is made of a polyurethane elastomer containing 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 More than 30.0N / mm 2 is as follows: The fatty acid metal salt is applied to the surface of the image bearing member so that the normalized ion intensity A of the amount of metal ions derived from the fatty acid metal salt, as measured by a time-of-flight secondary ion mass spectrometer, satisfies the following formula (1): A protective layer forming apparatus characterized by: 1E -4 <A<20E -4 (1) (2) The protective layer forming device according to (1) above, wherein the lubricant application blade has a laminated structure of at least two layers, that is, an edge layer and a base layer. (3) The protective layer forming device according to (1) or (2) above, wherein the edge angle of the ridgeline of the tip of the lubricant application blade is 90° or more and 140° or less. (4) The lubricant application blade 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, and the Martens hardness of the base layer is 0.5 N / mm 2 More than 2.0N / mm 2The protective layer forming apparatus according to any one of (1) to (3) above, wherein the polyurethane elastomer is: (5) The protective layer forming device according to any one of (1) to (4) above, wherein the lubricant application blade is pressed against the image carrier with a contact linear pressure of 0.5 N / m or more and 10.0 N / m or less. (6) an image carrier; The protective layer forming apparatus according to any one of (1) to (5) above, an electrostatic latent image forming means for forming an electrostatic latent image by exposing a charged image carrier; a visible image forming means for developing the electrostatic latent image with 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 means for removing toner remaining on the image carrier; An image forming apparatus comprising: [Explanation of symbols]

[0108] 1, 1Y, 1C, 1M, 1K imaging unit 2 frame 3, 3Y, 3C, 3M, 3K image carrier 4 Charging roller 5, 5Y, 5C, 5M, 5K developing device 6 Cleaning Device 7, 7Y, 7C, 7M, 7K 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 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 Fusing 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 application blade 151 First paper feed cassette 151a First paper feed roller 152 Second paper feed cassette 152b Second paper feed roller 153 Paper feed path 154 Delivery Roller Pair 162 Belt cleaning unit 162a Belt cleaning blade 500 Image forming device 601 Elastic member 602 Contact surface 6011 Edge layer 6012 base layer 6013 Support member 6014 Contact area between lubricant application blade and image carrier L laser light P Recording medium [Prior art documents] [Patent documents]

[0109] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-300861 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-39304 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-58539

Claims

1. A protective layer forming device for forming an image carrier protective layer by applying a lubricant to the surface of the image carrier using a lubricant application blade that contacts the surface of the image carrier, the lubricant is a fatty acid metal salt, a contact surface of the lubricant application blade that contacts the image bearing member is made of a polyurethane elastomer containing 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 is as follows: The fatty acid metal salt is applied to the surface of the image bearing member so that the normalized ion intensity A of the amount of metal ions derived from the fatty acid metal salt, as measured by a time-of-flight secondary ion mass spectrometer, satisfies the following formula (1): A protective layer forming apparatus characterized by: 1E －４ <A<20E －４ (1)

2. 2. The protective layer forming device according to claim 1, wherein the lubricant application blade has a laminated structure of at least two layers, that is, an edge layer and a base layer.

3. 3. The protective layer forming apparatus according to claim 1, wherein the lubricant application blade has a tip ridgeline having an edge angle of 90 degrees or more and 140 degrees or less.

4. The lubricant application blade 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 bearing member, and the Martens hardness of the base layer is 0.5 N / mm ２ 2.0N / mm or more ２ 3. The protective layer forming apparatus according to claim 1, wherein the polyurethane elastomer is one of the following:

5. 3. The protective layer forming apparatus according to claim 1, wherein the lubricant application blade is pressed against the image bearing member with a contact linear pressure of 0.5 N / m or more and 10.0 N / m or less.

6. an image carrier; The protective layer forming apparatus according to claim 1 or 2; an electrostatic latent image forming means for forming an electrostatic latent image by exposing a charged image carrier; a visible image forming means for developing the electrostatic latent image with 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 means for removing toner remaining on the image carrier; An image forming apparatus comprising:

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