Cleaning blades, imaging devices, and process cartridges

Abstract

A cleaning blade is provided. The cleaning blade includes a strip-shaped elastic blade and a support member that supports the elastic blade. The cleaning blade is configured so that a front ridge portion of the elastic blade contacts a moving cleaning target member and removes residual material from the surface of the cleaning target member. At least a surface layer portion of the elastic blade, including the front ridge portion, is formed of rubber having a hysteresis loss ratio of 15% or less.

Description

Technical Field

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

[0002] In existing electrophotographic imaging devices, a cleaning unit removes any residual toner adhering to the surface of an image carrier (hereinafter, may be referred to as a "cleaning target member"), from which the toner image has been transferred to a recording medium or an intermediate transfer medium in an imaging step. As a cleaning unit, a cleaning blade is used because the cleaning blade has a simple structure and excellent cleaning performance. The cleaning blade generally includes an elastic member and a supporting member formed of, for example, polyurethane rubber. The cleaning blade, in which the base end of the elastic member is supported by the supporting member, presses the contact portion (front end ridge portion) of the elastic member against the surface of the image carrier, blocks any toner remaining on the surface of the image carrier, and scrapes and removes the toner.

[0003] In recent years, energy-saving electrophotographic image forming apparatuses are required, and low-melting-point toners are being used more frequently.

[0004] However, if Figure 1A As shown in FIG. 1 , due to the increase in friction between the image carrier 123 and the cleaning blade 62, the existing polyurethane rubber cleaning blade 62 is pulled toward the moving direction of the image carrier 123, and the contact portion (front end ridge portion) 62c of the cleaning blade 62 is curled. In addition, if the cleaning blade 62 continues cleaning in a state where the contact portion 62c is curled, as shown in FIG. Figure 1B As shown, local wear X occurs at a position where the front end surface 62a of the cleaning blade 62 is separated from the contact portion 62c by some micrometers. If the cleaning blade 62 further continues cleaning in this state, the local wear X grows, and the contact portion 62c eventually chips away, as shown in FIG. Figure 1C If the contact portion 62c peels off, there will be a problem that the frictional force acts more strongly and a cleaning failure occurs. A specific problem is that the external additive adheres to the image carrier.

[0005] In order to provide a cleaning blade configured to appropriately clean polymerized colorant with small particle size even in a low-temperature, low-humidity environment, PTL 1 discloses a cleaning blade for an electrophotographic device, wherein the cleaning blade includes an elastic rubber member and a supporting member, and the elastic rubber member is formed of a material having a double-layer or more-layer structure including an edge layer and a layer other than the edge layer, and the material satisfies a relationship between hysteresis loss due to deflection and bending load of B / A<0.5 in a three-point bending test with the edge layer facing upward.

[0006] PTL 2 discloses a cleaning blade in which the modulus 100 of the surface layer of the elastic blade is set within a specific range.

[0007] The technology disclosed in PTL 1 has a problem in that the elastic blade wears out and becomes malfunctioning during the early stages of use because the technology is insufficient in suppressing damage due to repeated minute deformations of the elastic blade.

[0008] The technology disclosed in PTL 2 also has room for improvement in terms of suppression of wear of the elastic blade and cleaning performance on the cleaning target member.

[0009]

Citation List

[0010] [Patent Document]

[0011] [PTL 1] Japanese Unexamined Patent Application Publication No. 2008-268649

[0012] [PTL 2] Japanese Unexamined Patent Application Publication No. 2014-85595 Summary of the Invention

[0013] Technical issues

[0014] An object of the present disclosure is to provide a cleaning blade that suppresses wear of an elastic blade due to contact with a cleaning target member, suppresses residual matter from slipping through the cleaning blade or adhering to the cleaning target member, and can be used for a long period of time.

[0015] Technical Solution

[0016] According to an embodiment of the present disclosure, a cleaning blade includes a strip-shaped elastic blade and a support member that supports the elastic blade. The cleaning blade is configured so that a front ridge portion of the elastic blade contacts a moving cleaning target member and removes residual material from the surface of the target member. At least a surface layer portion of the elastic blade, including the front ridge portion, is formed from rubber having a hysteresis loss ratio of 15% or less.

[0017] Advantageous Effects of the Invention

[0018] The present disclosure can provide a cleaning blade that can be used for a long period of time by suppressing early wear of the elastic blade due to contact with the cleaning target member and by suppressing residual matter from slipping through the cleaning blade or adhering to the cleaning target member. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] [ Figure 1A ] Figure 1A is a schematic diagram illustrating an example of a conventional cleaning blade.

[0020] [ Figure 1B ] Figure 1B is a schematic diagram illustrating an example of a conventional cleaning blade.

[0021] [ Figure 1C ] Figure 1C is a schematic diagram illustrating an example of a conventional cleaning blade.

[0022] [ Figure 2A ] Figure 2A is a schematic diagram illustrating an example of a cleaning blade according to an embodiment of the present disclosure.

[0023] [ Figure 2B ] Figure 2B is a schematic diagram illustrating an example of a cleaning blade according to an embodiment of the present disclosure.

[0024] [ Figure 3 ] Figure 3 is a schematic diagram illustrating an example of a state in which a front end ridgeline portion of the elastic blade is in contact with a cleaning target member.

[0025] [ Figure 4 ] Figure 4 is a schematic diagram illustrating an example of a configuration of an imaging apparatus according to an embodiment of the present disclosure.

[0026] [ Figure 5 ] Figure 5 is a view illustrating an example of a schematic configuration of one of four imaging units of the imaging device.

[0027] [ Figure 6 ] Figure 6 is a diagram illustrating an example of the average circularity of toner.

[0028] [ Figure 7 ] Figure 7 : is a conceptual diagram showing an example of a hysteresis loss ratio. DETAILED DESCRIPTION

[0029] After careful study, the inventors have found that Figure 1B As shown, the conventional cleaning blade using a material having a high hysteresis loss ratio at the front end ridge line portion wears out at a position slightly away from the edge 62c, and if the cleaning blade continues to Figure 1A If the cleaning blade is used in the deformed state shown, it loses its cleaning ability significantly during the early stage of use and allows any residual matter such as toner to slip past the cleaning blade, or allows toner and external additives to adhere to the cleaning target member.

[0030] The present disclosure can solve the above-mentioned problem by using a material having a hysteresis loss ratio of 15% or less at a front ridgeline portion. Embodiments of the present disclosure will be described in detail below.

[0031] <Cleaning Target Member>

[0032] For example, the material, shape, structure and size of the cleaning target member are not particularly limited, and can be appropriately selected according to the intended purpose. The example of the shape of the cleaning target member includes drum shape, belt shape, flat plate shape and sheet shape. The size of the cleaning target member is not particularly limited, and can be appropriately selected according to the intended purpose, and is preferably a commonly used size.

[0033] The material of the cleaning target member is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the material of the cleaning target member include metals, plastics, and ceramics.

[0034] The cleaning target member is not particularly limited and can be appropriately selected depending on the intended purpose. When a cleaning blade is used in an image forming apparatus, examples of the cleaning target member include an image carrier.

[0035] <Residual substances>

[0036] The residual matter is not particularly limited and can be appropriately selected according to the intended purpose, as long as the residual matter adheres to the surface of the cleaning target member and is suitable as a target to be removed by the cleaning blade. Examples of the residual matter include toner, lubricant, inorganic particles, organic particles, garbage and dust, or a mixture thereof.

[0037] The following description is based on an example in which an image carrier such as a photoreceptor is used as a cleaning target member and the residual matter is toner. However, the present disclosure should not be construed as being limited to the example described below.

[0038] Figure 2A and Figure 2B is a schematic diagram illustrating an example of the cleaning blade of the present disclosure.

[0039] like Figure 2A As shown, the cleaning blade 62 includes a flat support member 621 formed of a rigid material such as metal or hard plastic and a strip-shaped elastic blade 622. The elastic blade 622 is fixed to one end of the support member 621 by, for example, an adhesive. The other end of the support member 621 is suspended on a case of the cleaning device.

[0040] Figure 3 1 is a schematic diagram illustrating a state in which the front end ridgeline portion of the elastic blade 622 is in contact with a cleaning target member (eg, a photoconductor).

[0041] like Figure 3As shown, the strip-shaped elastic scraper 622 has a front end ridge portion on one side of the elastic scraper 622, which is a free end facing the photoreceptor 3. The cleaning scraper 622 is configured to bring the front end ridge portion into contact with the surface of the photoreceptor 3 undergoing surface movement, and to remove and clean powder from the surface of the photoreceptor 3.

[0042] The elastic scraper 622 may be formed of a single layer, such as Figure 2A The elastic scraper 622 may be a laminate having a laminate structure including a base layer 6222 and a surface layer 6221 including a front end ridge line portion, as shown. Figure 2B shown.

[0043] For example, the shape, material, size, and structure of the base layer 6222 are not particularly limited and can be appropriately selected depending on the intended purpose. The size of the elastic blade 622 is not particularly limited and can be appropriately selected depending on the size of the cleaning target member.

[0044] The material of the elastic blade 622 is not particularly limited and can be appropriately selected depending on the intended purpose. For example, urethane rubber and urethane elastomer are suitable because high elasticity tends to be obtained.

[0045] The following method can be proposed as a preferred method of manufacturing the elastic scraper 622.

[0046] First, a polyurethane prepolymer is prepared using a polyol compound and a polyisocyanate compound. Next, a curing agent and, if necessary, a curing catalyst are added to the polyurethane prepolymer and stirred. The resulting product is then injected into a centrifugal molding device, heated and cross-linked, and molded into a cylindrical shape. The resulting product is stripped from the mold and partially cut into sheets. The sheet is stretched on a smooth surface, left to stand at room temperature, and aged. The resulting product is then cut into strips of predetermined size.

[0047] The polyol compound is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the polyol compound include high molecular weight polyols and low molecular weight polyols.

[0048] Examples of high molecular weight polyols include polyester polyols, which are condensates of alkylene glycol and aliphatic dibasic acid; polyester-based polyols, such as polyester polyols of alkylene glycol and adipic acid, such as ethylene adipate polyol, butylene adipate polyol, hexylene adipate polyol, ethylenepropylene adipate polyol, ethylenebutylene adipate polyol, and ethyleneneopentylene adipate polyol; polycaprolactone-based polyols, such as polycaprolactone polyols obtained by ring-opening polymerization of caprolactone; and polyether-based polyols, such as poly(oxytetramethylene) glycol and poly(oxypropylene) glycol. One of these high molecular weight polyols may be used alone, or two or more of these high molecular weight polyols may be used in combination.

[0049] Examples of low molecular weight polyols include divalent 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 trivalent or higher polyvalent alcohols such as 1,1,1-trimethylolpropane, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, trimethylolethane, 1,1,1-tris(hydroxyethoxymethyl)propane, diglycerol, and pentaerythritol. One of these low molecular weight polyols may be used alone, or two or more of these low molecular weight polyols may be used in combination.

[0050] Polyisocyanate compound is not particularly limited and can be suitably selected according to intended purpose.The example of polyisocyanate compound includes methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), xylene diisocyanate (XDI), naphthalene 1,5-diisocyanate (NDI), tetramethyl xylene diisocyanate (TMXDI), isophorone diisocyanate (IPDI), hydrogenated xylene diisocyanate (H6XDI), dicyclohexylmethane diisocyanate (H12MDI), hexamethylene diisocyanate (HDI), dimer acid diisocyanate (DDI), norbornene diisocyanate (NBDI) and trimethyl hexamethylene diisocyanate (TMDI).One of these polyisocyanate compounds can be used alone, or two or more of these polyisocyanate compounds can be used in combination.

[0051] The curing catalyst is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the curing catalyst include secondary amines such as 2-methylimidazole and salts of secondary amines; tertiary amines such as 1,2-dimethylimidazole, triethylenediamine, and diazabicycloundecene and salts of tertiary amines; alkali metal organic acid salts such as potassium acetate and potassium octoate; and organic metal salts such as dibutyltin dilaurate, bismuth carboxylate, and zirconium complexes.

[0052] The content of the curing catalyst is not particularly limited, may be appropriately selected depending on the intended purpose, and is preferably 0.01% by mass or more but 0.5% by mass or less, more preferably 0.05% by mass or more but 0.3% by mass or less.

[0053] The elastic scraper 622 may have a single-layer structure or a laminated structure including two or more layers. The material of the present disclosure having a hysteresis loss ratio of 15% or less generally has a low hardness. Herein, a laminated structure in which the base layer is formed of a rubber having a high hardness and the surface layer is formed of a material having a hysteresis loss ratio of 15% or less is preferred, because such a laminated structure can suppress the front ridge line from being partially solidified more than necessary and can satisfy wear resistance and followability.

[0054] The JIS-A hardness of the surface layer including the front ridge portion is preferably 50 degrees or more but 65 degrees or less, and the JIS-A hardness of the base layer is preferably 68 degrees or more but 85 degrees or less. The JIS-A hardness of the base layer is more preferably 70 degrees or more but 80 degrees or less. When the JIS-A hardness of the base layer is less than 68 degrees, it is more difficult to obtain a scraper linear pressure, and cleaning failures may occur. On the other hand, when the JIS-A hardness of the base layer is greater than 85 degrees, the base layer is easily plastically deformed, the scraper linear pressure is reduced in the long term, and cleaning failures may occur.

[0055] The JIS-A hardness is measured according to JIS K6253 and can be measured with, for example, a micro rubber hardness meter MD-1 available from Kobunshi Keiki Co., Ltd.

[0056] When the hysteresis loss ratio of the surface layer is greater than 15%, the leading end ridge line portion tends to undergo fatigue wear through repeated deformation during use and loses cleaning ability due to early wear.

[0057] The hysteresis loss rate is measured in accordance with JIS K6400-2 and can be measured using, for example, a texture analyzer EZTEST available from Shimadzu Corporation.

[0058] Specifically, a single-layer rubber sample is first processed into a dumbbell shape according to JIS K6251. The rubber sample is attached to a texture analyzer and extended (loaded) to 100% at the tensile speed specified in JIS K6251 (for example, 500 mm / min for Type 1 dumbbell shape), then returned (unloaded) to 0% extension at the same speed. The hysteresis loss ratio is calculated according to the following formula, where W1 represents the integrated value of the loading stress and W2 represents the integrated value of the unloading stress.

[0059] Hysteresis loss ratio = (W1-W2) / W1[%]

[0060] When the tanδ peak temperature of the surface layer is higher than 2 degrees Celsius, the surface layer has a higher hardness and a higher hysteresis loss ratio in a low-temperature environment. Therefore, in an environment such as winter, the surface layer tends to experience early wear and reduce cleaning ability.

[0061] The tan δ peak temperature can be measured using a strip sample using, for example, DMS6100 available from SII Nanotechnology Inc. under conditions such as a tensile mode, a frequency of 10 Hz, and a heating rate of 2 degrees Celsius / minute.

[0062] The amount of micro-pulp erosion (MSE) wear of the surface layer is effective as an indicator based on which to measure the rate of growth of abrasive wear, which occurs slightly due to the material sliding across the cleaning blade even when the cleaning blade maintains its cleaning performance. It has been found that when the amount of MSE wear exceeds 15 micrometers, wear growth suddenly becomes severe at a certain point in time.

[0063] The amount of MSE wear can be measured under the following conditions, for example, 100 g of a slurry liquid obtained by dispersing aluminum oxide particles having a particle size of 1 micron in water at a mass concentration of 3% is projected onto a smooth portion of a cleaning blade rubber at a speed of 100 m / sec using an MSE tester available from Palmeso Co., Ltd., and the wear depth is measured using a laser microscope (e.g., LEXT OLS4100 available from Olympus Corporation).

[0064] When the Martens hardness of the surface layer is less than 0.45N / mm 2 On the other hand, when the Martens hardness of the surface layer is greater than 0.75 N / mm 2 When the hysteresis loss ratio is greater than 15%, it is usually not desirable.

[0065] Martens hardness can be measured using an ultramicrohardness tester HM-2000 available from Fischer Instruments KK under the following conditions, for example, a Vickers indenter is pressed into the sample surface with a force of 9.8 mN for 30 seconds, held there for 5 seconds, and pulled out with a force of 9.8 mN within 30 seconds.

[0066] The average thickness of the elastic blade 622 is not particularly limited, may be appropriately selected depending on the intended purpose, and is preferably 1.0 mm or more but 3.0 mm or less.

[0067] <Supporting member>

[0068] For example, the shape, size, and material of the support member 621 are not particularly limited and can be appropriately selected according to the intended purpose. Examples of the shape of the support member 621 include a flat plate, a strip, and a sheet. The size of the support member 621 is not particularly limited and can be appropriately selected according to the size of the cleaning target member.

[0069] Examples of the material of the support member 621 include metal, plastic, and ceramic. Among these materials, a metal plate is preferable in terms of strength, and a steel plate such as stainless steel, an aluminum plate, and a phosphor bronze plate are particularly preferable.

[0070] The cleaning blade disclosed herein can maintain excellent cleaning performance over a long period of time because it suppresses curling of the contact portion of the front ridge portion that contacts the surface of the cleaning target member, as well as wear and debris of the contact portion of the front ridge portion during use. Therefore, the cleaning blade disclosed herein can be widely used in various fields. In particular, the cleaning blade disclosed herein can be suitably used in the imaging devices, imaging methods, and process cartridges described below.

[0071] (Imaging apparatus and imaging method)

[0072] The imaging device of the present disclosure includes at least an image carrier, a charging unit, an exposure unit, a developing unit, a transfer unit, a fixing unit, and a cleaning unit, and further includes other units appropriately selected as needed. The charging unit and the exposure unit can be collectively referred to as an electrostatic latent image forming unit.

[0073] The imaging method performed by the imaging device of the present disclosure includes at least a charging step, an exposure step, a developing step, a transferring step, a fixing step, and a cleaning step, and may also include other steps appropriately selected as needed. The charging step and the exposure step may be collectively referred to as an electrostatic latent image forming step.

[0074] The charging step may be performed by a charging unit. The exposing step may be performed by an exposing unit. The developing step may be performed by a developing unit. The transferring step may be performed by a transferring unit. The fixing step may be performed by a fixing unit. The cleaning step may be performed by a cleaning unit. Other steps may be performed by other units.

[0075] For example, the material, shape, structure, and size of the image carrier (hereinafter referred to as "electrophotographic photoreceptor" or "photoreceptor") are not particularly limited and can be appropriately selected from known properties. Examples of the shape of the image carrier include a drum shape and a belt shape. Examples of the material of the image carrier include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors (OPCs) such as polysilane and phthalopolymethine.

[0076] <Charging Step and Charging Unit>

[0077] The charging step is a step of charging the surface of the image carrier, and is performed by a charging unit.

[0078] For example, charging may be performed by applying a voltage to the surface of the image carrier using a charging unit.

[0079] The charging unit is not particularly limited and can be appropriately selected according to the intended purpose. Examples of the charging unit include known contact chargers including, for example, a conductive or semiconductive roller, a brush, a film, or a rubber blade, and non-contact chargers using corona discharge (e.g., a corotron and a scorotron).

[0080] The charging unit can have any form, such as a roller, a magnetic brush, or a fur brush. The form of the charging unit can be selected according to the specifications and form of the electrophotographic imaging device. When using a magnetic brush, it is formed by: various ferrite particles, such as Zn-Cu ferrite, as the charging unit, a non-magnetic conductive sleeve supporting the ferrite particles, and a magnetic roller enclosed within the sleeve. When using a fur brush, the fur is made of carbon, copper sulfide, metal, or metal oxide treated to impart conductivity, and the charger is formed by wrapping or attaching the fur around a core rod treated to impart conductivity using metal or any other substance.

[0081] The charger is not limited to the above-described contact type charger, but the contact type charger has an advantage in that an image forming apparatus with less ozone emission from the charger can be obtained.

[0082] Preferably, the charger is provided in contact with or non-contact with the image carrier, and is configured to charge the surface of the image carrier by applying DC and AC voltages superimposed on each other.

[0083] Preferably, the charger is a charging roller having a gap belt, and is disposed adjacent to the image carrier in a non-contact manner, and is configured to charge the surface of the image carrier when mutually superimposed DC and AC voltages are applied to the charging roller.

[0084] <Exposure Step and Exposure Unit>

[0085] The exposing step is a step of exposing the charged surface of the image carrier to light, and is performed by an exposing unit.

[0086] The exposure can be performed by, for example, exposing the surface of the image carrier to light in an imagewise manner using an exposure unit.

[0087] Optical systems involved in exposure are roughly divided into analog optical systems and digital optical systems.

[0088] An analog optical system is an optical system configured to project an original image directly onto an image carrier through an optical system. A digital optical system is an optical system configured to receive image information in the form of an electrical signal, convert the electrical signal into an optical signal, and expose an electrophotographic photoreceptor to the optical signal to form an image.

[0089] The exposure unit is not particularly limited and can be appropriately selected depending on the intended purpose, as long as the exposure unit can expose the surface of the image carrier charged by the charging unit to light in an imagewise manner into a desired image. Examples of the exposure unit include various exposure units such as a copier optical system, a rod lens array system, a laser optical system, a liquid crystal shutter optical system, and an LED optical system.

[0090] In the present disclosure, a back exposure system may be employed that is configured to imagewise expose the back side of an image carrier to light.

[0091] <Developing Step and Developing Unit>

[0092] The developing step is a step of developing the electrostatic latent image with a toner to form a visible image.

[0093] The electrostatic latent image can be developed, for example, with toner to form a visible image. This can be performed by a developing unit.

[0094] The developing unit is not particularly limited and can be appropriately selected from known developing units as long as the developing unit can develop an image with toner. Preferred examples of the developing unit include a developing unit including a developing device that stores toner and can apply the toner to the electrostatic latent image in a contact manner or a non-contact manner.

[0095] The developing device may be a dry developing type or a wet developing type, and may be a monochrome developing device or a multi-color developing device. Preferred examples of the developing device include a developing device including: an agitator configured to frictionally stir and charge the toner; and a rotatable magnetic roller.

[0096] For example, in a developing device, toner and carrier (as needed) are mixed and agitated. The resulting friction charges the toner and holds it in a chain-like manner on the surface of a rotating magnetic roller, forming a magnetic brush. Because the magnetic roller is positioned near the image carrier, the toner forming the magnetic brush on the magnetic roller surface is partially displaced onto the image carrier surface by an electrical attraction force. As a result, the electrostatic latent image is developed with the toner, and a visible image formed by the toner is formed on the image carrier surface.

[0097] The toner to be stored in the developing device may be a developer containing toner. The developer may be a single-component developer or a two-component developer.

[0098] -Toner-

[0099] The toner contains toner base particles and external additives, and further contains other components as needed.

[0100] The toner may be a monochrome toner or a color toner.

[0101] The toner base particles contain at least a binder resin and a colorant, and contain other components such as a releasing agent and a charge control agent as needed.

[0102] ---Binder Resin---

[0103] The binder resin is not particularly limited and can be appropriately selected according to the intended purpose. Examples of the binder resin include homopolymers of styrene or homopolymers of substitutes for styrene, such as polystyrene resins and polyvinyl toluene resins, styrene-p-chlorostyrene copolymers, styrene-propylene copolymers, styrene-vinyl toluene copolymers, styrene-methyl acrylate copolymers, styrene-ethyl acrylate copolymers, styrene-butyl acrylate copolymers, styrene-methyl methacrylate copolymers, styrene-ethyl methacrylate copolymers, styrene-butyl methacrylate copolymers, styrene-α-chloromethyl methacrylate copolymers, styrene-acrylonitrile copolymers, styrene-vinyl methyl ether copolymers, styrene-methyl vinyl ketone copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-maleic acid copolymers, styrene-maleic acid ester copolymers, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride resins, polyvinyl acetate resins, polyethylene resins, polypropylene resins, polyester resins, polyurethane resins, epoxy resins, polyvinyl butyral resins, polyacrylic acid resins, rosin, modified rosin, terpene resins, phenol resins, aliphatic hydrocarbons, aromatic petroleum resins, chlorinated paraffins, and paraffin waxes. One of these binder resins may be used alone, or two or more of these binder resins may be used in combination. Among these binder resins, polyester resins are particularly preferred because they can suppress the melt viscosity of the toner while ensuring the storage stability of the toner, compared to styrene-based resins and acrylic-based resins.

[0104] The polyester resin can be obtained by, for example, a polycondensation reaction between an alcohol component and a carboxylic acid component.

[0105] The alcohol component is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the alcohol component include: diols such as polyethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-propylene glycol, neopentyl glycol, and 1,4-butene glycol; etherified bisphenols such as 1,4-bis(hydroxymethyl)cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylene bisphenol A, and polyoxypropylene bisphenol A; and bisphenols obtained by substituting these alcohol components with saturated or unsaturated hydrocarbon groups containing 3 to 22 carbon atoms. Divalent alcohol monomers; other divalent alcohol monomers; trivalent or higher valent polyvalent alcohol monomers, such as sorbitol, 1,2,3,6-hexanetetraol, 1,4-sorbitan, pentaerythritol, dipentaerythritone, tripentaerythrital, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropylene glycol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane and 1,3,5-trihydroxymethylbenzene.

[0106] The carboxylic acid component is not particularly limited and can be appropriately selected according to the intended purpose. Examples of the carboxylic acid component include: monocarboxylic acids such as palmitic acid, stearic acid and oleic acid; maleic acid, fumaric acid, mesaconic acid, citraconic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid and malonic acid, divalent organic acid monomers obtained by substituting these acids with saturated or unsaturated hydrocarbon groups containing 3 to 22 carbon atoms, anhydrides of these acids, and dimer acids formed from lower alkyl esters and linolenic acid; and 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 3,3-dicarboxymethylbutyric acid, tetracarboxymethylmethane and 1,2,7,8-octanetetracarboxylic acid empol trimer acid, as well as trivalent or higher valent polyvalent carboxylic acid monomers, such as anhydrides of these acids.

[0107] ---Colorant---

[0108] Coloring agent is not particularly limited, and can be suitably selected from known dyes and pigments according to the intended purpose.The example of coloring agent comprises carbon black, aniline black dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, iron oxide yellow, ochre yellow, chrome yellow, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), sulfur fast yellow (5G, R), tartrate yellow lake, quinoline yellow lake, anthracene yellow BGL, isoindolinone yellow, iron oxide red, red lead (minium), lead vermilion, cadmium red, cadmium mercury red, antimony vermilion, permanent red 4R, para red (para Red), Fiser Red, p-Chloro-o-nitroaniline Red, Litho Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Sulphur Fast Ruby B, Brilliant Scarlet G, Litho Ruby GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Maroon 5B, Toluidine Maroon (maroon), Permanent Maroon F2K, Helio Maroon BL, Maroon 10B, BON Maroon Light, BON Maroon Medium (maroon medium), eosin lake, rhodamine lake B, rhodamine lake Y, alizarin lake, thioindigo red B, thioindigo maroon, oil red, quinacridone red, pyrazolone red, polyazo red, chrome vermilion, benzidine orange, pyrrolidone orange, oil orange, cobalt blue, azure blue, alkali blue lake, malachite blue lake, Victoria blue lake, metal-free phthalocyanine blue, phthalocyanine blue, fast sky blue, indanthrene blue (RS, BC), indigo, ultramarine, Prussian blue, anthraquinone blue, fast violet B, methyl violet lake, cobalt violet, manganese violet, dimethicone, Alkane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, viridian, emerald green, pigment green B, naphthol green B, green gold, acid green lake, malachite green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc oxide, and lithopone. One of these colorants may be used alone, or two or more of these colorants may be used in combination.

[0109] The content of the colorant in the toner is not particularly limited, may be appropriately selected depending on the intended purpose, and is preferably 1% by mass or more but 15% by mass or less, and more preferably 3% by mass or more but 10% by mass or less.

[0110] Colorants can be used in the form of masterbatches, which are composite materials of colorant and resin.

[0111] The resin is not particularly limited and can be appropriately selected from known resins according to the intended purpose. Examples of resins include polymers of styrene or polymers of substitutes for styrene, styrene-based copolymers, polymethyl methacrylate resins, butyl methacrylate resins, polyvinyl chloride resins, polyvinyl acetate resins, polyethylene resins, polypropylene resins, polyester resins, epoxy resins, epoxy polyol resins, polyurethane resins, polyamide resins, polyvinyl butyral resins, polyacrylic acid resins, rosin, modified rosin, terpene resins, aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, and paraffin waxes. One of these resins can be used alone, or two or more of these resins can be used in combination.

[0112] ---Release agent---

[0113] The releasing agent is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the releasing agent include wax.

[0114] Examples of waxes include carbonyl-containing waxes, polyolefin waxes, and long-chain hydrocarbons. One of these waxes can be used alone, or two or more of these waxes can be used in combination. Among these waxes, carbonyl-containing waxes are preferred.

[0115] Examples of carbonyl-containing waxes include polyalkanoates, polyalkanol esters, polyalkanoic acid amides, polyalkylamides, and dialkyl ketones. Examples of polyalkanoates include carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerol tribehenate, and 1,18-octadecanediol distearate. Examples of polyalkanol esters include tristearyl trimellitate and distearyl maleate. Examples of polyalkanoic acid amides include dibehenylamide. Examples of polyalkylamides include tristearyl trimellitate amide. Examples of dialkyl ketones include distearyl ketone. Among these carbonyl-containing waxes, polyalkanoates are particularly preferred.

[0116] Examples of the polyolefin wax include polyethylene wax and polypropylene wax.

[0117] Examples of long-chain hydrocarbons include paraffin wax and sasol wax.

[0118] The content of the releasing agent in the toner is not particularly limited, may be appropriately selected depending on the intended purpose, and is preferably 5% by mass or more but 15% by mass or less.

[0119] ---Charge Control Agent---

[0120] The charge control agent is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the charge control agent include nigrosine-based dyes, triphenylmethane-based dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine-based dyes, alkoxyamines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus or a phosphorus compound, tungsten or a tungsten compound, a fluorine-based activator, a salicylic acid metal salt, and a metal salt of a salicylic acid derivative.

[0121] The content of the charge control agent is not particularly limited, may be appropriately selected depending on the intended purpose, and is preferably 0.1 parts by mass or more but 10 parts by mass or less, and more preferably 0.2 parts by mass or more but 5 parts by mass or less, relative to 100 parts by mass of the toner.

[0122] --External Additives--

[0123] The external additive is not particularly limited and can be appropriately selected according to the intended purpose, as long as the external additive contains at least silica particles. The external additive may include: inorganic particles, such as inorganic particles of silica, titanium oxide, aluminum oxide, silicon carbide, silicon nitride and boron nitride; and resin particles, such as polymethyl methacrylate particles and polystyrene particles, which are obtained by soap-free emulsion polymerization and have an average particle size of 0.05 microns or more but 1 micron or less. One selected from these inorganic particles and resin particles can be used alone, or two or more selected from these organic particles and resin particles can be used in combination. Among these inorganic particles and resin particles, silica having a hydrophobized surface is particularly preferred.

[0124] Examples of silica include silicone-treated silica. The silicone-treated silica is silica whose surface is surface-treated (hydrophobized) with silicone oil.

[0125] The method of the surface treatment is not particularly limited and can be appropriately selected depending on the intended purpose.

[0126] Examples of silicone oil include dimethyl silicone oil, methyl hydrogen silicone oil, and methylphenyl silicone oil.

[0127] Commercially available products can be used as the siloxane-treated silica. Examples of commercially available products include RY200, R2T200S, NY50, and RY50 (all available from Nippon Aerosil Co., Ltd.).

[0128] --Other components--

[0129] Other components of the toner are not particularly limited and can be appropriately selected depending on the intended purpose. Examples of other components include a fluidity improver, a cleaning property improver, a magnetic material, and a metal soap.

[0130] Flow improvers improve hydrophobicity through surface treatment, preventing degradation of flow and chargeability even in high-humidity environments. Examples of flow improvers include silane coupling agents, silylating agents, silane coupling agents containing fluorinated alkyl groups, organic titanate-based coupling agents, aluminum-based coupling agents, silicone oils, and modified silicone oils.

[0131] A cleanability improver is added to the toner to remove any toner remaining on the image carrier or intermediate transfer medium after transfer. Examples of cleanability improvers include fatty acid metal salts, such as zinc stearate, calcium stearate, and stearic acid; and polymer particles produced by soap-free emulsion polymerization, such as polymethyl methacrylate particles and polystyrene particles. The polymer particles preferably have a relatively narrow particle size distribution, preferably having a volume average particle diameter of 0.01 micrometers or greater but 1 micrometer or less.

[0132] The magnetic material is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the magnetic material include iron powder, magnetite, and ferrite. Among these magnetic materials, white magnetic materials are preferred in terms of color tone.

[0133] —Method for producing toner—

[0134] The method for producing the toner is not particularly limited and can be appropriately selected from known toner production methods depending on the intended purpose. Examples of the method include a kneading pulverization method, a polymerization method, a dissolution suspension method, and a spray granulation method.

[0135] Among these methods, polymerization methods capable of producing a toner having high circularity and a small particle size, such as suspension polymerization, emulsion polymerization, and dispersion polymerization, are preferred in order to improve image quality.

[0136] ---Kneading and crushing method---

[0137] The kneading pulverization method is a method of, for example, melting and kneading a toner material including at least a binder resin and a colorant, and pulverizing and classifying the obtained kneaded product to produce base particles of the toner.

[0138] In the melting and kneading, the toner material is mixed, and the mixture is fed to a melt kneader to be melted and kneaded. As the melt kneader, for example, a single-axis or double-axis continuous kneader or a roller mill batch type kneader can be used. For example, the KTK type twin-axis extruder available from Kobe Steel, Ltd., the TEM type extruder available from Toshiba Machine Co., Ltd., the twin-axis extruder available from KCK Engineering Co., Ltd., the PCM type twin-axis extruder available from Ikegai Corp. and the co-kneader available from Buss AG can be appropriately used. It is preferred to carry out melting and kneading under appropriate conditions in which the molecular chains of the binder resin are not disconnected. Specifically, the melt kneading temperature is set based on the softening point of the binder resin. When the melt kneading temperature is excessively higher than the softening point, the molecular chains may be severely disconnected. When the melt kneading temperature is excessively lower than the softening point, dispersion may not be carried out.

[0139] In the pulverization, the kneaded product obtained by melting and kneading is pulverized. In the pulverization, it is preferred to first coarsely pulverize the kneaded product and then finely pulverize the kneaded product. Here, a method of pulverizing the kneaded product by causing it to collide with an impact plate in a jet, a method of pulverizing the kneaded product by causing particles of the kneaded product to collide with each other in a jet, and a method of pulverizing the kneaded product in a narrow gap between a mechanically rotating rotor and stator are preferably used.

[0140] In the classification, the pulverized product obtained in the pulverization is classified and adjusted into particles having a predetermined particle size. The classification can be performed by removing fine particles using, for example, a cyclone separator, a decanter, and a centrifuge.

[0141] After the pulverization and classification are completed, the pulverized product is classified in an air flow by, for example, centrifugal force. In this way, toner base particles having a predetermined particle size can be produced.

[0142] Next, an external additive is added to the toner base particles from the outside. When the toner base particles and the external additive are mixed and stirred using a mixer, the surface of the toner base particles is coated with the external additive while the external additive is being crushed. Here, in terms of durability, it is important that the external additive, such as silica particles, is uniformly and firmly attached to the toner base particles.

[0143] ---Polymerization method---

[0144] In a method for producing toner by polymerization, for example, a toner material comprising at least a modified polyester-based resin capable of forming urea or urethane bonds and a colorant is dissolved or dispersed in an organic solvent. The dissolved or dispersed product is then dispersed in an aqueous medium and subjected to a polyaddition reaction. The solvent of the dispersion is removed, and the resultant is washed. In this manner, a toner is obtained.

[0145] Examples of modified polyester-based resins capable of forming urea or urethane bonds include isocyanate-containing polyester prepolymers obtained by reacting terminal carboxyl or hydroxyl groups of polyester with polyvalent isocyanate compounds (PICs). Through a reaction between the polyester prepolymer and, for example, an amine, the molecular chains of the polyester prepolymer undergo one or both of crosslinking and elongation. The resulting modified polyester resin can improve hot offset printing performance while maintaining low-temperature fixability.

[0146] Examples of polyvalent isocyanate compounds (PICs) include aliphatic polyvalent isocyanates (e.g., tetramethylene diisocyanate, hexamethylene diisocyanate, and 2,6-diisocyanatomethyl hexanoate); alicyclic polyisocyanates (e.g., isophorone diisocyanate and cyclohexylmethane diisocyanate); aromatic diisocyanates (e.g., toluene diisocyanate and diphenylmethane diisocyanate); aromatic aliphatic diisocyanates (e.g., α,α,α',α'-tetramethylxylene diisocyanate); isocyanates; and products obtained by blocking polyisocyanates with, for example, phenol derivatives, oximes, and caprolactams. One of these polyvalent isocyanate compounds may be used alone, or two or more of these polyvalent isocyanate compounds may be used in combination.

[0147] The proportion of the polyvalent isocyanate compound (PIC) is not particularly limited and can be appropriately selected depending on the intended purpose. The equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] to the hydroxyl group [OH] of the hydroxyl group-containing polyester is preferably 5 / 1 to 1 / 1, more preferably 4 / 1 to 1.2 / 1, and even more preferably 2.5 / 1 to 1.5 / 1.

[0148] The number of isocyanate groups contained per molecule of the isocyanate group-containing polyester prepolymer (A) is not particularly limited, can be appropriately selected depending on the intended purpose, and is preferably 1 or more, more preferably 1.5 to 3 on average, and still more preferably 1.8 to 2.5 on average.

[0149] Examples of the amine (B) to be reacted with the polyester prepolymer include divalent amine compounds (B1), trivalent or higher-valent polyvalent amine compounds (B2), amino alcohols (B3), aminothiols (B4), amino acids (B5), and products obtained by blocking the amino groups of B1 to B5 (B6).

[0150] Examples of the divalent amine compound (B1) include aromatic diamines (e.g., phenylenediamine, diethyltoluenediamine, and 4,4′-diaminodiphenylmethane); alicyclic diamines (e.g., 4,4′-diamino-3,3′-dimethyldicyclohexylmethane, diaminecyclohexane, and isophoronediamine); and aliphatic diamines (e.g., ethylenediamine, tetramethylenediamine, and hexamethylenediamine).

[0151] Examples of the trivalent or higher-valent polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine.

[0152] Examples of the amino alcohol (B3) include ethanolamine and hydroxyethylaniline.

[0153] Examples of the aminomercaptan (B4) include aminoethylmercaptan and aminopropylmercaptan.

[0154] Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid.

[0155] Examples of the product (B6) obtained by blocking the amino groups of B1 to B5 include ketimine compounds obtained from the amines of B1 to B5 and ketones (e.g., acetone, methyl ethyl ketone, and methyl isobutyl ketone), and Among these amines (B), B1 and a mixture of B1 and a small amount of B2 are particularly preferred.

[0156] The proportion of the amine (B) is not particularly limited and can be appropriately selected depending on the intended purpose. The equivalent ratio [NCO] / [NHx] of the isocyanate groups [NCO] in the isocyanate group-containing polyester prepolymer (A) to the amino groups [NHx] in the amine (B) is preferably 1 / 2 to 2 / 1, more preferably 1.5 / 1 to 1 / 1.5, and even more preferably 1.2 / 1 to 1 / 1.2.

[0157] The method of producing a toner by the above-mentioned polymerization method can produce a toner having a small particle size and a spherical shape at low cost with low environmental impact.

[0158] The disperser used for dispersion is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the disperser include a low-speed shearing disperser, a high-speed shearing disperser, a friction disperser, a high-pressure jet disperser, and an ultrasonic disperser.

[0159] Among these dispersers, a high-speed shearing disperser is preferable because the high-speed shearing disperser can control the particle size of the dispersion (oil droplets) to 2 μm or more but 20 μm or less.

[0160] When a high-speed shearing disperser is used, conditions such as the number of rotations, dispersion time, and dispersion temperature may be appropriately selected depending on the intended purpose.

[0161] The rotation speed is not particularly limited and can be appropriately selected depending on the intended purpose, and is preferably 1,000 rpm or more but 30,000 rpm or less, more preferably 5,000 rpm or more but 20,000 rpm or less.

[0162] The dispersion time is not particularly limited and may be appropriately selected depending on the intended purpose, and is preferably 0.1 minute or longer but 5 minutes or shorter for a batch type.

[0163] The dispersion temperature is not particularly limited and may be appropriately selected depending on the intended purpose, and is preferably 0° C. or higher but 150° C. or lower, more preferably 40° C. or higher but 98° C. or lower under pressure. Generally, dispersion is easier at a higher dispersion temperature.

[0164] The amount of the aqueous medium used when dispersing the toner material in the aqueous medium is not particularly limited, may be appropriately selected depending on the intended purpose, and is preferably 50 parts by mass or more but 2,000 parts by mass or less, more preferably 100 parts by mass or more but 1,000 parts by mass or less, relative to 100 parts by mass of the toner material.

[0165] The method for removing the organic solvent from the dispersion liquid is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the method include a method of gradually raising the temperature of the entire reaction system and evaporating the organic solvent in the oil droplets, and a method of spraying the dispersion liquid into a dry atmosphere and removing the organic solvent in the oil droplets.

[0166] When the organic solvent is removed, toner base particles are formed. The toner base particles may be subjected to, for example, washing and drying, and further subjected to, for example, classification. Classification may be performed by removing fine particles using, for example, a cyclone separator, a decanter, and centrifugation in a liquid, or may be performed after drying.

[0167] The obtained toner base particles can be mixed with particles of an external additive and, if necessary, with, for example, a charge control agent. Here, applying a mechanical impact can suppress, for example, the detachment of particles of an external additive from the surface of the toner base particles.

[0168] The method of applying mechanical impact is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the method include a method of applying impact to the mixture using a scraper rotating at high speed, and a method of supplying the mixture to a high-speed air flow and accelerating the mixture so that the particles collide with each other or collide with the particles on an appropriate impact plate.

[0169] The device used in this method is not particularly limited and can be appropriately selected according to the intended purpose. The example of the device includes ONGMILL (available from Hosokawa Micron Corporation), an I-type mill (available from Nippon Pneumatic Mfg. Co., Ltd.) modified to have a lower pulverizing air pressure, a hybridization system (available from Nara Machinery Co., Ltd.), a KRYPTRON system (available from Kawasaki Heavy Industries, Ltd.), and an automatic mortar.

[0170] The average circularity of the toner is not particularly limited and may be appropriately selected depending on the intended purpose, and is preferably 0.97 or greater, more preferably 0.97 or greater but 0.98 or less. When the average circularity is less than 0.97, the toner may not have satisfactory transferability, or a high-quality image free of dust particles may not be obtained.

[0171] The average circularity of the toner can be measured with, for example, a flow-type particle image analyzer FPIA-1000 available from Sysmex Corporation.

[0172] The volume average particle diameter of the toner is not particularly limited and can be appropriately selected depending on the intended purpose, and is preferably 5.5 μm or less.

[0173] The ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is not particularly limited and can be appropriately selected depending on the intended purpose, and is preferably 1.00 or greater but 1.40 or less. A ratio (Dv / Dn) closer to 1.00 indicates a sharper particle size distribution. Toners having such a small particle size and a narrow particle size distribution have a uniform charge level distribution and can produce high-quality images with little background fog, and the transfer rate of the toner in an electrostatic transfer method is high.

[0174] The volume average particle diameter and particle size distribution of the toner can be measured with, for example, a Coulter counter TA-II and a Coulter multisizer (both available from Beckman Coulter Inc.), which are toner particle size distribution measuring instruments based on the Coulter counting method.

[0175] The toner may be mixed with a magnetic carrier and used as a two-component developer. In this case, the mass ratio between the carrier and the toner in the two-component developer is not particularly limited and can be appropriately selected depending on the intended purpose. The toner is preferably present in an amount of 1 part by mass or more but 10 parts by mass or less relative to 100 parts by mass of the carrier.

[0176] Examples of the magnetic carrier include iron powder, ferrite powder, magnetite powder, and magnetic resin carriers having a particle size of about 20 μm or more but 200 μm or less.

[0177] The coating resin is not particularly limited and can be appropriately selected according to the intended purpose. Examples of coating resins include: halogenated olefin resins such as urea-formaldehyde resins, melamine resins, benzoguanamine resins, urea resins, polyamide resins, epoxy resins, polyethylene and polyvinylidene resins, acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, polystyrene resins, styrene-acrylic acid copolymer resins, and polyvinyl chloride; polyester-based resins such as polyethylene terephthalate resins and polybutylene terephthalate resins; and polycarbonate-based resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene resins, polyhexafluoropropylene resins, copolymers of ethylene difluoride and acrylic monomers, copolymers of vinylidene fluoride and vinyl fluoride, fluorine terpolymers of tetrafluoroethylene, vinylidene fluoride, and non-fluorinated monomers, and silicone resins.

[0178] For example, conductive powder can be added to the coating resin as needed. Examples of conductive powders include metal powder, carbon black, titanium oxide, tin oxide, and zinc oxide. The average particle size of these conductive powders is preferably 1 micron or less. When the average particle size of the conductive powder is greater than 1 micron, it may be difficult to control the resistance.

[0179] The toner may also be used as a one-component magnetic toner or a non-magnetic toner containing no carrier.

[0180] <Transfer Step and Transfer Unit>

[0181] The transfer step is a step of transferring the visible image to a recording medium. In a preferred embodiment, an intermediate transfer medium is used, and the visible image is primarily transferred to the intermediate transfer medium, and then secondarily transferred to the recording medium. A more preferred embodiment includes a primary transfer step of transferring the visible image to the intermediate transfer medium using two or more color toners (preferably a full-color toner) to form a composite transfer image, and a secondary transfer step of transferring the composite transfer image to the recording medium.

[0182] For example, the transfer can be performed by charging the visible image on the image carrier using a transfer unit. This can be performed by the transfer unit. In a preferred embodiment, the transfer unit includes a primary transfer unit configured to transfer the visible image to an intermediate transfer medium to form a composite transfer image, and a secondary transfer unit configured to transfer the composite transfer image to a recording medium.

[0183] The intermediate transfer medium is not particularly limited and can be appropriately selected from known transfer media depending on the intended purpose. Examples of the intermediate transfer medium include a transfer belt.

[0184] Preferably, the transfer unit (primary transfer unit and secondary transfer unit) includes at least a transfer device configured to charge the visible image formed on the image carrier so that it is peeled off to the recording medium side. A single transfer unit may be used, or two or more transfer units may be used. Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.

[0185] A representative example of the recording medium is plain paper. However, the recording medium is not particularly limited and can be appropriately selected according to the intended purpose, as long as the unfixed developed image can be transferred to the recording medium. For example, a PET substrate for OHP can also be used.

[0186] <Fixing Step and Fixing Unit>

[0187] The fixing step is a step of fixing the toner image transferred to the recording medium. A fixing unit can be used to fix the toner image. When two or more colors of toner are used, the toner image can be fixed each time a toner of any color is transferred to the recording medium, or the toner images of all colors can be fixed after all the toner images of all colors are transferred to the recording medium and superimposed on each other. The fixing unit is not particularly limited, and a heat fixing type using a known heating and pressing unit can be used. Examples of heating and pressing units include a combination of a heating roller and a pressing roller, and a combination of a heating roller, a pressing roller and an endless belt. The heating temperature is not particularly limited and can be appropriately selected according to the intended purpose, and is preferably 80 degrees Celsius or higher but 200 degrees Celsius or lower. As needed, for example, a known optical fixing device can be used in combination with the fixing unit.

[0188] <Cleaning Step and Cleaning Unit>

[0189] The cleaning step is a step of removing toner remaining on the image carrier, and may be appropriately performed by a cleaning unit.

[0190] As the cleaning unit, the cleaning blade of the present disclosure is used.

[0191] The elastic member of the cleaning blade preferably contacts the surface of the image carrier with a pressing force of 10 N / m or greater but 100 N / m or less. If the pressing force is less than 10 N / m, toner may pass through the contact portion of the cleaning blade where the elastic member contacts the surface of the image carrier, potentially causing cleaning failure. If the pressing force is greater than 100 N / m, the cleaning blade may curl due to increased friction at the contact portion. The pressing force is preferably 10 N / m or greater but 50 N / m or less.

[0192] The pressing force can be measured with a measuring instrument available from Kyowa Electronic Instruments Co., Ltd. in which a small-sized compression type load cell is embedded.

[0193] An angle θ formed between a tangent line extending along a portion of the cleaning blade where the elastic member contacts the surface of the image carrier and the end surface of the cleaning blade is not particularly limited, may be appropriately selected depending on the intended purpose, and is preferably 65 degrees or more but 85 degrees or less.

[0194] When the angle θ is less than 65 degrees, the cleaning blade may curl. When the angle θ is greater than 85 degrees, cleaning failure may occur.

[0195] <Other steps and other units>

[0196] Examples of other units include a charge eliminating unit, a recycling unit, and a control unit.

[0197] Examples of other steps include a charge elimination step, a recovery step, and a control step.

[0198] - Charge Eliminating Step and Charge Eliminating Unit -

[0199] The charge-eliminating step is a step of applying a charge-eliminating bias to the image carrier to eliminate charges from the image carrier, and may be suitably performed by a charge-eliminating unit.

[0200] The charge-eliminating unit is not particularly limited and needs to be able to apply a charge-eliminating bias to the image carrier. The charge-eliminating unit can be appropriately selected from known charge-eliminating devices. Preferred examples of the charge-eliminating unit include a charge-eliminating lamp.

[0201] -Recycling steps and recycling units-

[0202] The recycling step is a step of recycling the toner removed in the cleaning step to the developing unit, and may be appropriately performed by a recycling unit.

[0203] The recovery unit is not particularly limited. Examples of the recovery unit include known conveying units.

[0204] -Control steps and control unit-

[0205] The control step is a step of controlling each step and can be appropriately performed by the control unit.

[0206] The control unit is not particularly limited and can be appropriately selected depending on the intended purpose, as long as the control unit can control the operation of each unit. Examples of the control unit include devices such as a sequencer and a computer.

[0207] Examples of the imaging apparatus of the present disclosure will be described with reference to the accompanying drawings.

[0208] Figure 4 1 is a schematic diagram illustrating a configuration example of an image forming apparatus 500 of the present disclosure. The image forming apparatus 500 includes four image forming units 1Y, 1C, 1M, and 1K for yellow, magenta, cyan, and black (hereinafter referred to as Y, C, M, and K). These image forming units use Y, C, M, and K toners having different colors as image forming materials for forming images, but are otherwise identical to each other.

[0209] A transfer unit 60 including an intermediate transfer belt 14 serving as an intermediate transfer medium is provided above the four image forming units 1. In this configuration, toner images of respective colors formed on the surfaces of photoreceptors 3Y, 3C, 3M, and 3K included in the image forming units 1Y, 1C, 1M, and 1K, which will be described in detail below, are transferred onto the surface of the intermediate transfer belt 14 in an overlapping manner.

[0210] An optical writing unit 40 is provided below the four imaging units 1. The optical writing unit 40, serving as a latent image forming unit, irradiates the photoreceptors 3Y, 3C, 3M, and 3K of the imaging units 1Y, 1C, 1M, and 1K with laser light L generated based on image information. As a result, electrostatic latent images of Y, C, M, and K are formed on the photoreceptors 3Y, 3C, 3M, and 3K. While the laser light L emitted from the light source is deflected by a polygonal mirror 41 driven by a motor for rotation, the optical writing unit 40 irradiates the photoreceptors 3Y, 3C, 3M, and 3K with the laser light L via a plurality of optical lenses and reflective mirrors. Instead of this configuration, a configuration for performing laser scanning using an LED array may be employed.

[0211] The first paper feed cassette 151 and the second paper feed cassette 152 are arranged in a vertically stacked state below the optical writing unit 40. A plurality of recording media P stacked in the form of a paper bundle is stored in each paper feed cassette. The first paper feed roller 151a and the second paper feed roller 152a are in contact with the uppermost recording medium P, respectively. When the first paper feed roller 151a is driven by the driving unit to Figure 4When the first paper feed cassette 151 rotates counterclockwise, the uppermost recording medium P in the first paper feed cassette 151 is fed to the paper feed path 153, which is arranged in a manner extending in the vertical direction. Figure 4 When the second paper feed roller 152a is driven by the driving unit to Figure 4 When the cassette 152 rotates counterclockwise, the uppermost recording medium P in the second paper feed cassette 152 is fed to the paper feed path 153 .

[0212] A plurality of pairs of conveying rollers 154 are provided in the paper feeding path 153. The recording medium P fed to the paper feeding path 153 is sandwiched between the rollers of the paired conveying rollers 154 and is passed from the paper feeding path 153 to the recording medium P. Figure 4 The bottom of the transmission upwards.

[0213] A pair of registration rollers 55 is provided at the downstream end of the paper feed path 153 in the conveying direction. The pair of registration rollers 55 stops rotating immediately after the registration rollers 55 catch the recording medium P fed out from the pair of conveying rollers 154 between the registration rollers 55. The pair of registration rollers 55 then sends the recording medium P to a secondary transfer nip described below at an appropriate timing.

[0214] Figure 5 is a view showing a schematic configuration of one of the four imaging units 1 .

[0215] like Figure 5 As shown, the image forming unit 1 includes a drum-shaped photoreceptor 3 serving as an image carrier. Although the photoreceptor 3 has a drum shape, the photoreceptor 3 may have a sheet shape or an endless belt shape.

[0216] For example, a charging roller 4, a developing device 5, a primary transfer roller 7, a cleaning device 6, a lubricant applying device 10, and a charge eliminating lamp are disposed around the photoreceptor 3. The charging roller 4 is a charging member included in the charging device serving as a charging unit. The developing device 5 is a developing unit configured to convert a latent image formed on the surface of the photoreceptor 3 into a toner image. The primary transfer roller 7 is a primary transfer member included in the primary transfer device serving as a primary transfer unit configured to transfer the toner image on the surface of the photoreceptor 3 to the intermediate transfer belt 14. The cleaning device 6 is a cleaning unit configured to clean any toner remaining on the photoreceptor 3 after the toner image is transferred to the intermediate transfer belt 14. The lubricant applying device 10 is a lubricant applying unit configured to apply lubricant to the surface of the photoreceptor 3 after cleaning by the cleaning device 6. The charge eliminating lamp is a charge eliminating unit configured to eliminate the surface potential on the cleaned photoreceptor 3.

[0217] The charging roller 4 is disposed in a non-contact manner at a predetermined distance from the photoreceptor 3 and is configured to charge the photoreceptor 3 to a predetermined polarity and a predetermined potential. Based on image information from an optical writing unit 40 serving as a latent image forming unit, the surface of the photoreceptor 3, which has been uniformly charged by the charging roller 4, is irradiated with laser light L, and an electrostatic latent image is formed on the surface of the photoreceptor 3.

[0218] The developing device 5 includes a developing roller 51 serving as a developer carrier. A developing bias is applied to the developing roller 51 from a power source. In the housing of the developing device 5, a supply screw 52 and a stirring screw 53 are provided, which are configured to stir the developer stored in the housing of the developing device 5 while conveying the developer in directions opposite to each other. A doctor 54 is also provided, which is configured to adjust the developer carried on the developing roller 51. The toner in the developer stirred and conveyed by the two screws, namely the supply screw 52 and the stirring screw 53, is charged to a predetermined polarity. The developer is scraped onto the surface of the developing roller 51. The scraped developer is regulated by the doctor 54, and the toner adheres to the latent image on the photoreceptor 3 at the developing area facing the photoreceptor 3.

[0219] The cleaning device 6 includes, for example, a cleaning blade 62. The cleaning blade 62 contacts the photoconductor 3 in a direction opposite to a direction in which the surface of the photoconductor 3 moves.

[0220] The lubricant applying device 10 includes, for example, a solid lubricant 103 and a lubricant pressure spring 103a, and uses a fur brush 101 as an application brush for applying the solid lubricant 103 to the photoreceptor 3. The solid lubricant 103 is held on a holder 103b and is pressurized toward the fur brush 101 by the lubricant pressure spring 103a. As the photoreceptor 3 rotates in its rotational direction, the solid lubricant 103 is scraped off by the fur brush 101, which rotates in the direction in which the fur brush 101 is removed, and is applied to the photoreceptor 3. During non-image forming operations, the lubricant applied to the photoreceptor maintains a coefficient of friction of 0.2 or less on the surface of the photoreceptor 3.

[0221] The charging device is a non-contact adjacent arrangement type, in which the charging roller 4 is arranged adjacent to the photoreceptor 3. As the charging device, known configurations such as a gridless corotron, a grid corotron, and a solid-state charger can be used. Of these charging methods, the contact charging method or the non-contact adjacent arrangement method is particularly preferred, and has advantages such as high charging efficiency, low ozone emissions, and device miniaturization.

[0222] As the light source of the laser L of the optical writing unit 40 and the light source such as the charge eliminating lamp, all kinds of light-emitting articles such as fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium vapor lamps, light-emitting diodes (LEDs), laser diodes (LDs) and electroluminescence (EL) can be used.

[0223] In order to enable illumination with only light in a desired wavelength range, various filters such as a sharp cutoff filter, a bandpass filter, a near-infrared cutoff filter, a dichroic filter, an interference filter, and a color conversion filter may be used.

[0224] Among these light sources, light emitting diodes and laser diodes that have high irradiation energy and are capable of emitting long-wavelength light of 600 nm or longer but 800 nm or shorter are suitably used.

[0225] Used as Figure 4 The transfer unit 60 shown in FIG. 1 includes, in addition to the intermediate transfer belt 14, a belt cleaning unit 162, a first bracket 63, and a second bracket 64. The transfer unit 60 also includes, for example, 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 driven by the drive roller 67 to move in a continuous manner. Figure 4 The intermediate transfer belt 14 is a circularly moving belt that rotates in a counterclockwise direction in the middle of the photosensitive body 3Y, 3C, 3M, and 3K, and is suspended on these eight roller members in a tensioned state. The four primary transfer rollers 7Y, 7C, 7M, and 7K form a primary transfer nip by clamping the cyclically moving intermediate transfer belt 14 between them and the photoreceptors 3Y, 3C, 3M, and 3K. The primary transfer rollers apply a transfer bias with a polarity opposite to that of the toner (e.g., positive) to the back side (inner peripheral surface of the loop) of the intermediate transfer belt 14. As the intermediate transfer belt 14 circulates, it passes through the primary transfer nip 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 transferred to the outer surface of the intermediate transfer belt in an overlapping state. As a result, a four-color overlapping toner image (hereinafter, may be referred to as a four-color toner image) is formed on the intermediate transfer belt 14.

[0226] The secondary transfer backup roller 66 forms a secondary transfer nip by sandwiching the intermediate transfer belt 14 between itself and a secondary transfer roller 70 positioned outside the intermediate transfer belt loop. At a point in time when the recording medium P can synchronize with the four-color toner image on the intermediate transfer belt 14, the pair of registration rollers 55 deliver the recording medium P, sandwiched between the registration rollers 55, to the secondary transfer nip. Due to the secondary transfer electric field formed between the secondary transfer roller 70, which applies a secondary transfer bias, and the secondary transfer backup roller 66, as well as the nip pressure, the four-color toner image on the intermediate transfer belt 14 is collectively secondary-transferred to the recording medium P in the secondary transfer nip. The four-color toner image then blends with the white color of the recording medium P, resulting in a full-color toner image.

[0227] The remaining toner that has not been transferred to the recording medium P adheres to the intermediate transfer belt 14 that has passed through the secondary transfer nip. The remaining toner is cleaned by the belt cleaning unit 162. The belt cleaning unit 162 is configured to scrape and remove the remaining toner on the intermediate transfer belt 14 by a belt cleaning blade 162a that contacts the outer surface of the intermediate transfer belt 14.

[0228] The first bracket 63 of the transfer unit 60 is configured to swing at a predetermined rotation angle around the rotation axis of the auxiliary roller 68 as the solenoid is driven on and off. When forming a monochrome image, the image forming apparatus 500 swings the first bracket 63 at a predetermined rotation angle by driving the solenoid. Figure 4 By this rotation, the primary transfer rollers 7Y, 7C and 7M for Y, C and M rotate slightly counterclockwise around the rotation axis of the auxiliary roller 68. Figure 4 The intermediate transfer belt 14 is rotated counterclockwise in the middle to separate the intermediate transfer belt 14 from the photoreceptors 3Y, 3C, and 3M for Y, C, and M. Then, among the four imaging units 1Y, 1C, 1M, and 1K, only the imaging unit 1K for K is driven to form a monochrome image. This makes it possible to avoid wear of each member constituting the imaging units 1 for Y, C, and M due to wasteful driving of these imaging units 1 during the formation of a monochrome image.

[0229] The fixing unit 80 is provided at Figure 4 The fixing unit 80 includes a pressure heating roller 81 including a heat source such as a halogen lamp inside and a fixing belt unit 82. The fixing belt unit 82 includes, for example, a fixing belt 84 serving as a fixing member, a heating roller 83 including a heat source such as a halogen lamp inside, a tension roller 85, a driving roller 86, and a temperature sensor. The fixing belt 84 having an endless shape is formed with a plurality of rollers. Figure 4 The fixing belt 84 is moved in a counterclockwise circular motion and is suspended on the heating roller 83, the tension roller 85 and the driving roller 86 in a tensioned state. As the fixing belt 84 is moved in a circular motion, the back side is heated by the heating roller 83. Figure 4 The pressing and heating roller 81 rotating clockwise contacts the outer surface of the fixing belt 84 heated in this manner at the portion of the fixing belt 84 suspended on the heating roller 83. As a result, a fixing nip is formed where the pressing and heating roller 81 and the fixing belt 84 contact each other.

[0230] A temperature sensor is positioned outside the loop of fixing belt 84, facing the outer surface of fixing belt 84 with a predetermined gap therebetween. It is configured to sense the surface temperature of fixing belt 84a immediately before entering the fixing nip. The sensing result is transmitted to the fixing power supply circuit. Based on the temperature sensor's sensing result, the fixing power supply circuit controls whether power is supplied to the heat source included in the heating roller 83 and the heat source included in the pressure heating roller 81.

[0231] The recording medium P that has passed through the secondary transfer nip is separated from the intermediate transfer belt 14 and then fed into the fixing unit 80. The recording medium P is heated and pressurized by the fixing belt 84 and is nipped by the fixing nip in the fixing unit 80. Figure 4 As a result, the full-color toner image is fixed on the recording medium P.

[0232] The recording medium P that has undergone the fixing process in this manner passes between the rollers of the pair of paper discharge rollers 87 and is then discharged to the outside of the apparatus. A stacking portion 88 is formed on the upper surface of the housing of the main body of the imaging apparatus 500. The recording medium P discharged to the outside of the apparatus by the pair of paper discharge rollers 87 is sequentially stacked on the stacking portion 88.

[0233] Four toner cartridges 100Y, 100C, 100M, and 100K storing Y, C, M, and K toners are arranged 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 imaging units 1Y, 1C, 1M, and 1K. These toner cartridges 100Y, 100C, 100M, and 100K are attachable to and detachable from the imaging apparatus main body independently of the imaging units 1Y, 1C, 1M, and 1K.

[0234] Next, the imaging operation of the imaging apparatus 500 will be described.

[0235] First, when a print execution signal is received from, for example, an operating unit, a predetermined voltage or current is sequentially applied to the charging roller 4 and the developing roller 51 at a predetermined timing. Similarly, a predetermined voltage or current is sequentially applied to the light sources such as the optical writing unit 40 and the charge eliminating lamp at a predetermined timing. Synchronously, the photoreceptor 3 is driven by a photoreceptor driving motor serving as a driving unit to generate a signal. Figure 5 Rotate in the direction of the arrow.

[0236] When the photoreceptor 3 Figure 4 When rotating in the direction of the arrow in the figure, first, the surface of the photoreceptor 3 is uniformly charged to a predetermined potential by the charging roller 4. Then, the optical writing unit 40 irradiates the photoreceptor 3 with laser light L corresponding to image information, and eliminates the charge from the portion of the surface of the photoreceptor 3 irradiated with the laser light L to form an electrostatic latent image.

[0237] The surface of the photoreceptor 3, on which the electrostatic latent image is formed, is rubbed in a sliding manner by a magnetic brush of developer formed on the developing roller 51 in the area where the photoreceptor 3 faces the developing device 5. Here, the negatively charged toner on the developing roller 51 is moved toward the electrostatic latent image by a predetermined developing bias applied to the developing roller 51, thereby being transformed into a toner image (or developed). Each imaging unit 1 performs the same imaging process, and toner images of respective colors are formed on the surfaces of the photoreceptors 3Y, 3C, 3M, and 3K of the imaging units 1Y, 1C, 1M, and 1K.

[0238] In the above-described manner, in the image forming apparatus 500, the developing device 5 reversely develops the electrostatic latent image formed on the photoreceptor 3 using toner charged to a negative polarity. In this embodiment, an example of a non-contact charging roller method using an N / P type (negative / positive, toner adheres to a location with a low potential) has been described. However, this is a non-limiting example.

[0239] The toner images of the respective colors formed on the surfaces of the photoreceptors 3Y, 3C, 3M, and 3K are sequentially primarily transferred so that the toner images overlap one after another 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.

[0240] The four-color toner image formed on the intermediate transfer belt 14 is transferred to a recording medium P, which is then fed from the first paper feed cassette 151 or the second paper feed cassette 152 to the secondary transfer nip via the pair of registration rollers 55. Once the recording medium P stops while being sandwiched between the pair of registration rollers 55, it is adjusted to align with the leading edge of the image on the intermediate transfer belt 14 and fed to the secondary transfer nip. The recording medium P, to which the toner image has been transferred, is separated from the intermediate transfer belt 14 and conveyed to the fixing unit 80. The recording medium P, to which the toner image has been transferred, then passes through the fixing unit 80, where the toner image is fixed to the recording medium P using heat and pressure. The recording medium P, to which the toner image has been fixed, is discharged outside the imaging apparatus 500 and stacked on the stacking section 88.

[0241] At the same time, the belt cleaning unit 162 removes untransferred residual toner from 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.

[0242] The cleaning device 6 removes any remaining toner that has not been transferred from the surface of the photoreceptor 3, from which the toner images of the respective colors have been transferred to the intermediate transfer belt 14 at the primary transfer nip. Then, the lubricant applying device 10 applies lubricant to the surface of the photoreceptor 3, and the charge eliminating lamp eliminates the charge from the surface of the photoreceptor 3.

[0243] like Figure 5 As shown, as an imaging unit 1 of an imaging device 500, a photoreceptor 3 and, for example, a charging roller 4, a developing device 5, a cleaning device 6, and a lubricant applying device 10 serving as a process unit are housed within a frame 2. In this manner, the imaging unit 1 serving as a process cartridge can be attached to and removed from the main body of the imaging device 500 as a whole. In the imaging device 500, the photoreceptor 3 and the process unit of the imaging unit 1 serving as a process cartridge are replaced as a whole with new ones. However, the photoreceptor 3, the charging roller 4, the developing device 5, the cleaning device 6, and the lubricant applying device 10 can be replaced with new ones unit by unit. The lubricant applying device is not essential.

[0244] As the toner to be used in the image forming apparatus 500, in order to improve image quality, a polymerized toner produced by a suspension polymerization method, an emulsion polymerization method, or a dispersion polymerization method (which can produce a toner having high circularity and a small particle size) is preferably used. In general, in terms of forming a high-resolution image, a polymerized toner having a volume average particle size of 5.5 μm or less is preferred.

[0245] (Processing Cartridge)

[0246] The process cartridge of the present disclosure includes at least an image carrier and a cleaning unit configured to remove toner remaining on the image carrier, and further includes other units as necessary.

[0247] As the cleaning unit, the cleaning blade of the present disclosure is used.

[0248] A processing cartridge is a device (component) which internally includes the image carrier and cleaning blade of the present disclosure, and further includes at least one unit selected from a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge elimination unit, and can be attached to and detached from an imaging device.

[0249] Example

[0250] The present disclosure will be described below by way of examples and comparative examples. The present disclosure should not be construed as being limited to the following examples. Unless otherwise specifically provided, any values ​​expressed in parts represent values ​​in parts by mass.

[0251] <Hysteresis Loss Ratio>

[0252] According to JIS K6400-2, the hysteresis loss ratio of the surface layer including the front end ridge line portion is measured as follows: a sample cut into a dumbbell shape type 7 is stretched 100% at a tensile speed of 200 mm / min using a texture analyzer obtained from Shimadzu Corporation and the sample is relaxed to 0% at the same speed, and the integral value of the stress during the test is calculated.

[0253] <JIS-A hardness of elastic member>

[0254] The JIS-A hardness of the surface layer and the base layer was measured using a micro rubber hardness meter MD-1 obtained from Kobunshi Keiki Co., Ltd. in accordance with JIS K6253.

[0255] <Tanδ peak temperature>

[0256] The tanδ peak temperature of the surface layer was measured in tensile mode at a frequency of 10 Hz and a heating rate of 2 °C / min using a bar sample and a DMS6100 obtained from SII Nanotechnology Inc. in accordance with JIS K6394.

[0257] <MSE wear amount>

[0258] 100 g of a slurry liquid obtained by dispersing alumina particles with a particle size of 1 μm in water at a mass concentration of 3% was projected onto the smooth part of a clean blade rubber at a speed of 100 m / s at a projection rate of 2 g / min using an MSE tester obtained from Palmeso Co., Ltd., and the wear depth was measured using a laser microscope (e.g., LEXT OLS4100 obtained from Olympus Corporation).

[0259] <Martens hardness>

[0260] The Martens hardness was measured using a super microhardness meter HM-2000 obtained from Fischer Instruments K.K. under the condition that the Vickers indenter was brought into contact with a position 20 μm away from the front ridge line part of the surface layer, pressed into this position with a force of 8 mN for 30 s, held there for 5 s, and pulled out with a force of 9.8 mN within 30 s.

[0261] <Average roundness of toner>

[0262] The average circularity of the toner is measured with a flow-type particle image analyzer (FPIA-2000, obtained from Sysmex Corporation). Specifically, 0.1 mL to 0.5 mL of a surfactant (alkylbenzene sulfonate) used as a dispersant is added to water (100 mL to 150 mL) previously removed from impurity solids in a container, and further about 0.1 g to 0.5 g of a measurement sample (toner) is added to the resultant. Subsequently, an ultrasonic disperser is used to disperse the suspension in which the toner is dispersed for 1 minute to 3 minutes so that the concentration of the dispersion is 3,000 particles / microliter to 10,000 particles / microliter. The resultant is set in the above-mentioned analyzer, and the shape and distribution of the toner are measured. Based on the measurement results, C2 / C1 is calculated, where C1 represents a particle size having a particle size of 3,000 particles / microliter to 10,000 particles / microliter. Figure 6 (A) represents the perimeter of the actual projected shape of the toner with the projected area S shown, and C2 represents the perimeter of the toner with the same projected area S. Figure 6 (B) The circumference of the true circle shown. The average value of the C2 / C1 value was obtained as the average circularity.

[0263] <Volume Average Particle Diameter of Toner>

[0264] The volume average particle size of toner is measured by Coulter counter method. Specifically, the number distribution and volume distribution data of the toner measured by Coulter counter 2E type (obtained from Beckman Coulter Inc.) are sent to a personal computer via an interface (obtained from Nikkaki Bios Co., Ltd.) and analyzed. More specifically, a 1% by mass NaCl aqueous solution obtained by using primary sodium chloride (primary sodium chloride) is prepared as an electrolyte solution. 0.1mL to 5mL of a surfactant (alkylbenzene sulfonate) used as a dispersant is added to an electrolyte aqueous solution (100mL to 150mL). 2mg to 20mg of the toner used as a test sample is further added to the resulting mixture, and an ultrasonic disperser is used to disperse the resulting mixture for 1 minute to 3 minutes. 100mL to 200mL of the electrolyte aqueous solution is poured into another beaker, and the solution through dispersion treatment is added to the resulting mixture with a predetermined concentration. The resulting mixture is fed into a Coulter counter 2E type.

[0265] The particle sizes of 50,000 toner particles are measured using a 100 micrometer aperture. Toner particles having a particle size of 2.00 microns or greater but 32.0 microns or less are measured using the following thirteen channels: 2.00 microns or greater but less than 2.52 microns; 2.52 microns or greater but less than 3.17 microns; 3.17 microns or greater but less than 4.00 microns; 4.00 microns or greater but less than 5.04 microns; 5.04 microns or greater but less than 6.35 microns; 6.35 microns or greater but less than 8.00 microns; 8.00 microns or greater but less than 10.08 microns; 10.08 microns or greater but less than 12.70 microns; 12.70 microns or greater but less than 16.00 microns; 16.00 microns or greater but less than 20.20 microns; 20.20 microns or greater but less than 25.40 microns; 25.40 microns or greater but less than 32.00 microns; and 32.00 microns or greater but less than 40.30 microns.

[0266] Then, the volume average particle diameter is calculated according to the relationship "volume average particle diameter = ∑XfV / ∑fV", where "X" represents the representative diameter in each channel, "V" represents the equivalent volume at the representative diameter in each channel, and "f" represents the number of particles in each channel.

[0267] (Example 1)

[0268] <Toner Production Example>

[0269] Toner base particles having an average circularity of 0.98 and a volume average particle diameter of 4.9 μm were produced by a polymerization method. The obtained toner base particles (100 parts by mass) were mixed with silica particles having a small diameter (H2000 obtained from Clariant AG) (1.5 parts by mass), titanium oxide particles having a small diameter (MT-150AI obtained from TAYCA Corporation) (0.5 parts by mass), and silica particles having a large particle diameter (UFP-30H obtained from Denka Company Limited) using a HENSCHEL mixer to produce a toner.

[0270] <Cleaning Blade Production Example>

[0271] Prepare urethane rubber (obtained from Nitta Chemical Industrial Products Co., Ltd.) and cut into predetermined sizes, wherein a polyester-based urethane rubber adjusted to a hardness of 61 degrees by a centrifugal molding method and a polyester-based urethane rubber adjusted to a hardness of 74 degrees are sequentially laminated as the surface layer and the base layer, respectively. The resultant is assembled with a supporting member having a predetermined size to prepare a cleaning blade. The thickness of the surface layer is 0.5 mm, and the thickness of the base layer is 1.5 mm. By adjusting the prescription, such as the amount of isocyanate added and the type and mixing ratio of the crosslinking agent, a rubber with a desired hysteresis loss ratio is obtained in a manner that simultaneously satisfies the hardness and tan δ peak temperature shown in the table.

[0272] <Evaluation of Cleaning Blade>

[0273] Next, the cleaning blade 1 produced as above was attached to a color multifunction peripheral (RICOH IM C6000) at a predetermined attachment angle (about 79 degrees) by a predetermined amount of leading end engagement (under a linear pressure of 20 N / m).

[0274] Using a color multifunction peripheral (RICOH IM C6000) loaded with the above-described toner, a chart (A4 size, latitudinally long) having an image area ratio of 0.5% and including a longitudinal band portion was output on 100,000 sheets in an environment of 23 degrees Celsius and 55% RH, with three prints / job. Subsequently, the cleaning ability, the wear depth of the leading edge ridge portion, the local wear on the leading edge ridge portion, and the MSE wear depth in the surface layer were evaluated in the following manner.

[0275] <Cleaning ability>

[0276] After outputting this chart on 100,000 sheets of paper, an evaluation image (4A size, long in latitude) representing a three-band chart with a longitudinal band pattern of 43 mm width (relative to the sheet running direction) was output on 20 sheets of paper. The output image was then visually observed and the cleaning ability was evaluated according to the following criteria. Abnormal images were defined as images that appeared in the form of streaks or bands in the printed image, or as white spot images.

[0277] <Evaluation Criteria>

[0278] A: No abnormal images.

[0279] B: Minor abnormality was observed, but there is no quality problem.

[0280] C: There is an abnormal image.

[0281] <Wear Depth of the Front Ridge Line Portion, Local Wear of the Front Ridge Line, and MSE Wear Depth in the Surface Layer>

[0282] These properties were calculated by measuring the shape of the front end ridgeline portion of the cleaning blade using a laser microscope (LEXT OLS4100 available from Olympus Corporation) Any local wear (such as chipping) of the front end ridgeline portion was observed.

[0283] (Examples 2 to 15 and Comparative Examples 1 to 7)

[0284] These Examples and Comparative Examples are the same as Example 1, except that the cleaning blades used were formed of a single layer of urethane rubber (obtained from Nitta Chemical Industrial Products Co., Ltd.) or a combination of a surface layer and a base layer having different formulations laminated therein (both obtained from Nitta Chemical Industrials Products Co., Ltd.). The performance values ​​and evaluation results of each cleaning blade are shown in Tables 1-1-1 to 1-3-2 below.

[0285] The compounds represented by abbreviations in the table are as follows.

[0286] -MDI: 4,4'-diphenylmethane diisocyanate

[0287] -TDI: 2,4-toluene diisocyanate

[0288] [Table 1-1-1]

[0289]

[0290]

[0291] [Table 1-1-2]

[0292]

[0293]

[0294] [Table 1-2-1]

[0295]

[0296]

[0297] [Table 1-2-2]

[0298]

[0299]

[0300] [Table 1-3-1]

[0301]

[0302] [Table 1-3-2]

[0303]

[0304] It can be seen from the results in Table 1-1-1 to Table 1-3-2 that the cleaning ability and wear performance of the cleaning scraper of the embodiment having a hysteresis loss ratio of 15% or less in the surface layer including the front end ridge line part are better than the cleaning ability and wear performance of the cleaning scraper of the comparison example that does not meet this condition.

[0305] These results indicate that the cleaning blade of the present disclosure suppresses curling due to contact with the photoreceptor, as well as powder slipping and adhesion, and can be used for a long period of time.

[0306] For example, aspects of the present disclosure are as follows.

[0307] <1> A cleaning scraper comprising:

[0308] an elastic scraper having a strip shape; and

[0309] a supporting member that supports the elastic scraper,

[0310] wherein the cleaning blade is configured to bring a front end ridge portion of the elastic blade into contact with a moving cleaning target member and remove residual matter from a surface of the cleaning target member, and

[0311] At least a surface layer portion of the elastic blade including the front end ridge line portion is formed of rubber having a hysteresis loss ratio of 15% or less.

[0312] <2> according to <1> The cleaning scraper,

[0313] The surface layer portion including the front end ridgeline portion to be in contact with the cleaning target member is formed of rubber having a tan δ peak temperature of 2 degrees Celsius or lower.

[0314] <3> according to <1> or <2> The cleaning scraper,

[0315] The surface layer portion including the leading end ridgeline portion to be in contact with the cleaning target member is formed of rubber having an MSE wear amount of 15 μm or less.

[0316] <4> according to <1> to <3> Any one of the cleaning blades,

[0317] The surface layer portion including the front end ridgeline portion to be in contact with the cleaning target member is formed of rubber having a JIS-A hardness of 50 degrees or more but 65 degrees or less.

[0318] <5> according to <1> to <4> Any one of the cleaning blades,

[0319] The cleaning blade is a laminate formed of a plurality of rubber layers having different JIS-A hardnesses.

[0320] <6> according to <1> to <5> Any one of the cleaning blades,

[0321] wherein the surface layer portion including the front end ridge line portion to be in contact with the cleaning target member is subjected to a pressure of 0.45 N / mm 2 or greater but 0.75N / mm 2 The rubber is formed with a Martens hardness of 1000 nm or less.

[0322] <7> An imaging device comprising:

[0323] Image carrier;

[0324] a charging unit configured to charge a surface of the image carrier;

[0325] an exposure unit configured to expose the charged image carrier to light to form an electrostatic latent image;

[0326] a developing unit configured to develop the electrostatic latent image with toner to form a visible image;

[0327] a transfer unit configured to transfer the visible image to a recording medium;

[0328] a fixing unit configured to fix the transfer image transferred to the recording medium; and

[0329] a cleaning unit configured to remove any toner remaining on the image carrier,

[0330] The cleaning unit is based on <1> to <6> The cleaning blade according to any one of the preceding claims.

[0331] <8> A process cartridge comprising at least:

[0332] Image carrier; and

[0333] a cleaning unit configured to remove any toner remaining on the image carrier,

[0334] The cleaning unit is based on <1> to <6> The cleaning blade according to any one of the preceding claims.

[0335] according to <1> to <6> Any one of the cleaning blades, according to <7> The imaging device, and according to <8> The processing cartridge can solve various problems in the related technical field and achieve the objectives of the present disclosure.

[0336]

Reference Symbol List

[0337] 1. 1Y, 1C, 1M, 1K: Imaging unit

[0338] 2: Framework

[0339] 3. 3Y, 3C, 3M, 3K: Photoreceptors

[0340] 4: Charging roller

[0341] 5. 5Y, 5C, 5M, 5K: Development device

[0342] 6: Cleaning device

[0343] 7, 7Y, 7C, 7M, 7K: Primary transfer roller

[0344] 10: Lubricant application device

[0345] 14: Intermediate transfer belt

[0346] 40: Optical writing unit

[0347] 41: Polyhedron

[0348] 51: Developing roller

[0349] 52: Supply screw

[0350] 53: Mixing screw

[0351] 54: Scraper

[0352] 55: Paired registration rollers

[0353] 60: Transfer unit

[0354] 62: Cleaning scraper

[0355] 62a: Front surface

[0356] 62b: Clean the scraper surface

[0357] 62c: Front ridge

[0358] 63: First bracket

[0359] 64: Second bracket

[0360] 66: Secondary transfer support roller

[0361] 67: driving roller

[0362] 68: Auxiliary roller

[0363] 69: Tension roller

[0364] 70: Secondary transfer roller

[0365] 80: Fusing unit

[0366] 81: Pressurized heating roller

[0367] 82: Fusing belt unit

[0368] 83: Heating roller

[0369] 84: Fusing belt

[0370] 85: Tension roller

[0371] 86: driving roller

[0372] 87: Pair of paper ejection rollers

[0373] 88: Stacking part

[0374] 100Y, 100C, 100M, 100K: Toner cartridge

[0375] 101: Brush

[0376] 103: Solid lubricant

[0377] 103a: Lubricant pressure spring

[0378] 103b: Bracket

[0379] 123: Image carrier

[0380] 151: First paper feeder

[0381] 151a: First paper feed roller

[0382] 152: Second paper feeder

[0383] 152a: Second paper feed roller

[0384] 153: Paper feed path

[0385] 154: Pair of conveyor rollers

[0386] 162: With cleaning unit

[0387] 162a: With cleaning scraper

[0388] 500: Imaging equipment

[0389] 621: Supporting members

[0390] 622: Elastic scraper (single layer)

[0391] 6221: Surface layer including front ridge portion (laminate)

[0392] 6222: Base layer (laminate)

[0393] L: Laser

[0394] P: Recording medium

[0395] X: Wear

Claims

1. A cleaning scraper, comprising: An elastic scraper having a strip shape; and a supporting member that supports the elastic scraper, wherein the cleaning blade is configured to bring a front end ridge portion of the elastic blade into contact with a moving cleaning target member and remove residual matter from a surface of the cleaning target member, and At least a surface layer portion of the elastic blade including the front end ridge line portion is formed of rubber having a hysteresis loss ratio of 15% or less.

2. The cleaning blade according to claim 1, The surface layer portion including the front end ridgeline portion to be in contact with the cleaning target member is formed of rubber having a tan δ peak temperature of 2 degrees Celsius or lower.

3. The cleaning blade according to claim 1 or 2, The surface layer portion including the leading end ridgeline portion to be in contact with the cleaning target member is formed of rubber having an MSE wear amount of 15 μm or less.

4. The cleaning blade according to any one of claims 1 to 3, The surface layer portion including the front end ridgeline portion to be in contact with the cleaning target member is formed of rubber having a JIS-A hardness of 50 degrees or more but 65 degrees or less.

5. The cleaning blade according to any one of claims 1 to 4, The cleaning blade is a laminate formed of a plurality of rubber layers having different JIS-A hardnesses.

6. The cleaning blade according to any one of claims 1 to 5, wherein the surface layer portion including the front end ridge line portion to be in contact with the cleaning target member is subjected to a pressure of 0.45 N / mm 2 or greater but 0.75N / mm 2 The rubber is formed with a Martens hardness of 1000 nm or less.

7. An imaging device comprising: Image carrier; a charging unit configured to charge a surface of the image carrier; an exposure unit configured to expose the charged image carrier to light to form an electrostatic latent image; a developing unit configured to develop the electrostatic latent image with toner to form a visible image; a transfer unit configured to transfer the visible image to a recording medium; a fixing unit configured to fix the transferred image transferred to the recording medium; and a cleaning unit configured to remove any toner remaining on the image carrier, The cleaning unit is a cleaning blade according to any one of claims 1 to 6.

8. A process cartridge comprising: Image carrier; and a cleaning unit configured to remove any toner remaining on the image carrier, The cleaning unit is a cleaning blade according to any one of claims 1 to 6.

Images