JP5396778B2 - Image carrier protecting agent, protective layer forming method, protective layer forming apparatus, image forming apparatus, and process cartridge - Google Patents

Description

  The present invention relates to a protective layer forming method, an image carrier protecting agent, a protective layer forming apparatus, an image forming apparatus and a process cartridge using the protective layer forming apparatus, and more particularly to a technique for forming a protective layer on the surface of an image carrier.

  As is well known, in electrophotographic image formation, an electrostatic latent image is formed by an electrostatic charge on an image carrier having a photosensitive layer containing a photoconductive substance and the like, and the electrostatic toner is charged on the electrostatic latent image. Is attached to form a visible image. This visible image is transferred to a recording medium such as paper and then fixed on the recording medium by heat, pressure, solvent gas, etc., and an output image is obtained.

  In such image formation, a two-component development method using frictional charging by stirring and mixing the toner and the carrier and a method of charging the toner without using a carrier by a method of charging the toner for visualization. It is roughly divided into a one-component development system. This one-component development method is further classified into a magnetic one-component development method and a non-magnetic one-component development method depending on whether or not a magnetic force is used to hold toner on the developing roller.

  Conventionally, in a copying machine or a multi-function machine based on a copying machine that requires high speed and image reproducibility, the requirements for charging stability of the toner, start-up property, long-term stability of image quality, etc. Many component development methods are employed. On the other hand, one-component development systems are often used in small printers, facsimiles, and the like, which have great demands for space saving and cost reduction.

  In recent years, in any of the development methods, the colorization of output images has progressed, and the demand for higher image quality and stabilization of image quality has become stronger than ever. In order to achieve such high image quality, the average particle size of the toner is reduced, the particle shape has no angular portion, and the toner has a more round shape.

In addition, an electrophotographic image forming apparatus generally charges a drum-shaped or belt-shaped image carrier uniformly while rotating the image carrier, regardless of the development method, and the image carrier by laser light or the like. A latent image pattern is formed thereon, the latent image pattern is visualized with toner (toner image), and transferred onto a recording medium. Then, the toner component that has not been transferred remains on the image carrier after the toner image is transferred to the recording medium. When these residuals are conveyed to the charging process as they are, the charging of the image carrier is prevented from being uniformly charged. Usually, after the transfer process, the toner remaining on the image carrier is removed by a cleaning blade or the like. Is removed by the cleaning means, and the surface of the image carrier is sufficiently cleaned, and then charging is performed.
As described above, the surface of the image carrier is subjected to various physical stresses and electrical stresses in each process such as charging, development, transfer, and cleaning, and the surface state changes as the usage time elapses. Of these stresses, stress due to friction in the cleaning process wears the image carrier and causes scratches. In order to solve this problem, in order to reduce the frictional force between the image carrier and the cleaning blade, many proposals have been made on various lubricants, supply of lubricating components, and a method of forming a lubricating film. ing.

  For example, in order to extend the life of the photoreceptor and the cleaning blade, it has been proposed to form a lubricant film on the surface of the photoreceptor by supplying a solid lubricant mainly composed of zinc stearate to the surface of the photoreceptor (for example, patents). References 1, 2). In particular, in Patent Document 2, the friction force between the image carrier and the cleaning member is reduced by supplying various lubricants to which inorganic fine particles are added to a solid lubricant mainly composed of zinc stearate on the surface of the photoreceptor. I can do it.

  Furthermore, by supplying various lubricants to which boron nitride is added to a solid lubricant mainly composed of zinc stearate on the surface of the photoreceptor, even if it receives electrical stress on the surface of the image carrier due to the charging process, There has also been proposed a configuration in which the lubricity is hardly lowered and a lubricant film can be formed over the entire surface of the image carrier to maintain high lubricity (for example, Patent Document 3).

  On the other hand, in recent years, a toner using a polymerization method has been put on the market in order to improve image quality and reduce manufacturing energy. These polymerized toners have excellent characteristics such as fewer angular portions and smaller average particle diameters than toners produced by a pulverization method. However, these features are affected by the shape and particle size of a method for cleaning the surface of the image carrier by pressing the edge of a cleaning member represented by rubber blade cleaning against the surface of the image carrier. As a result, it is difficult for the edge portion to be dammed, and the residual toner component tends to be poorly cleaned.

  On the other hand, the above-described lubricant molded product is manufactured by cast molding in which a powder material as a raw material is melted and filled in a mold. Therefore, reduction of manufacturing cost and manufacturing energy by melting has been an issue.

  Therefore, for the purpose of reducing such production cost and production energy, a lubricating powder comprising at least one lubricating compound selected from melamine cyanurate, polytetrafluoroethylene, fatty acid amide, fatty acid metal salt and molybdenum disulfide. The mixture of the body material and the thermoplastic resin particles can maintain a good cleaning property as a protective agent. Moreover, the lubricant molding which solidifies powder by direct compression molding is proposed (for example, patent documents 4-6).

  In addition, a lubricant molded product that directly solidifies powder by compression molding is used, and the lubricant is supplied to the surface of the image carrier only during non-image formation when the developer is not supplied from the developing device to the image carrier. An image forming apparatus characterized by the above has also been proposed (for example, Patent Document 7).

Japanese Patent Publication No.51-22380 JP 2005-171107 A JP 2006-350240 A JP 2000-330441 A JP 2005-99125 A Japanese Patent Laid-Open No. 10-49017

  However, as described above, the stress on the image carrier is not only received from the cleaning process, but the electrical stress particularly in the charging process greatly changes the state of the surface of the image carrier. Such an electrical stress is conspicuous in the contact charging method and the proximity charging method accompanied by a discharge phenomenon near the surface of the image carrier. In these charging methods, many active species and reaction products are generated on the surface of the image carrier, and many active species and reactive organisms generated in the atmosphere in the discharge region are adsorbed on the surface of the image carrier. .

  For this reason, a lubricant using zinc stearate as described in Patent Document 1 covers the surface of the image carrier relatively evenly and gives good lubricity. However, when this lubricating layer repeatedly passes through the charging step, The acid decomposes and may eventually remain on the surface of the image carrier or the charging member as zinc oxide. Residual zinc oxide has hygroscopicity, and the resistance decreases due to moisture adsorption in the atmosphere, so in a high humidity environment, the electrostatic charge on the image carrier cannot be retained, and the electrostatic latent image is obscured, A so-called blurred image, in which an image defect occurs, may occur.

  Moreover, zinc stearate has a major problem in terms of cleaning properties. In other words, in a normal image forming process, a cleaning method using a blade is adopted as a means for removing untransferred toner after transfer from the photosensitive member. However, zinc stearate causes the toner to slip through this blade. There is.

  If the toner passes through the cleaning blade, the toner appears directly in the image or the contamination of the charging member is further accelerated. The toner slipping becomes more noticeable as the toner becomes spherical with a small particle diameter. In addition, since a material using zinc stearate has a large amount of toner passing through, the cleaning blade is worn and the image forming apparatus has a short life.

  In Patent Document 2 and Patent Document 3, cleaning properties are improved by adding fine particles to zinc stearate. However, when these lubricants are molded, if they are produced by cast molding in which a molten lubricant is filled in a mold, the molded solid matter becomes very hard and cannot be supplied via a brush roller. Even if the supply is possible due to the strong brush and high pressure, the lubricant cannot be supplied stably over a long period of time.

  In Patent Document 4, Patent Document 5, and Patent Document 6, a lubricant solidified by compression molding is used. However, the lubricant does not sufficiently protect the photoreceptor, and the photoreceptor is scratched. Filming occurs.

  In Patent Document 7, a lubricant solidified by compression molding is used, and the lubricant particle size used for the lubricant is 3 μm to 20 μm. However, the particle size is too small and solidification by compression molding is difficult.

  The first object of the present invention is to realize a stable supply of a protective agent over a long period of time in view of the above-described problems of the present situation, a sufficient protection effect on the surface of the image carrier, and a film filling to the image carrier. An object of the present invention is to provide an image carrier protecting agent that realizes prevention of ming and contamination of a charging member.

The second object of the present invention is to provide a sufficient image carrier surface protecting effect, to prevent the wear and deterioration of the cleaning member, to prevent the toner from slipping out, and to the image carrier by providing the image carrier protective agent. It is an object of the present invention to provide an image forming method that realizes prevention of filming and prevention of contamination of a charging member.
A third object of the present invention is to provide a protective layer forming apparatus for forming a good image carrier protective layer.

  A fourth object of the present invention is to provide an image forming apparatus capable of stably obtaining a good quality image over a long period of time.

  A fifth object of the present invention is to provide a process cartridge capable of stably obtaining a good quality image.

(1) At least image carrier protection used to form a protective layer on the surface of the image carrier by applying or adhering to the surface of the image carrier by a brush roller disposed opposite to the surface of the image carrier. An agent,
The image carrier protective agent is solidified by compression molding by adding fine particles to a fatty acid metal salt, and the following formula (1) is applied to the tip diameter per brush hair of the brush roller.

An image carrier protecting agent, wherein the relationship is established.
( 2 ) The image carrier protective agent according to ( 1), wherein the image carrier protective agent contains a hydrophobic organic compound.
( 3 ) The image bearing member protecting agent according to (1) or (2) , wherein the hydrophobic organic compound used in the image bearing member is a metal salt of a fatty acid.
( 4 ) The method for forming a protective layer according to any one of (1) to (3), wherein a substance having a lamellar crystal is used as the hydrophobic organic compound used in the image carrier protective agent.
( 5 ) A protective layer forming apparatus for forming a protective layer using the image carrier protective agent according to any one of (1) to (4),
An apparatus for forming a protective layer, wherein the protective layer is formed by applying or adhering the image carrier protective agent to the surface of the image carrier.
( 6 ) The protective layer forming apparatus according to ( 5 ), wherein the image carrier protective agent is supplied to the surface of the image carrier through a supply member.
( 7 ) The protective layer forming apparatus according to ( 5 ) or ( 6 ), further comprising a layer forming member that presses the image carrier protective agent supplied to the surface of the image carrier to form a film.
( 8 ) at least an image carrier that has undergone a step of carrying a toner image;
Transfer means for transferring the toner image on the image carrier to a transfer medium;
In an image forming method using a protective layer forming means for applying or adhering an image carrier protective agent to the surface of the image carrier after the toner image is transferred to a transfer medium,
An image forming method comprising using the image carrier protecting agent according to any one of (1) to ( 3 ) as the image carrier protecting agent.
( 9 ) At least an image carrier that has undergone a step of carrying a toner image;
A transfer device for transferring the toner image on the image carrier to a transfer medium;
In an image forming apparatus comprising a protective layer forming device for applying or adhering an image carrier protective agent to the surface of the image carrier after the toner image is transferred to a transfer medium,
An image forming apparatus using the protective layer forming apparatus according to any one of ( 5 ) to ( 7 ) as the protective layer forming apparatus.
( 10 ) A cleaning device is provided on the downstream side of the transfer device and the upstream side of the protective layer forming device to remove toner remaining on the surface of the image carrier from the surface by rubbing against the image carrier. It is Te and wherein the image forming apparatus according to (9) (11) according to claim wherein said image bearing member, characterized in that it comprises a thermosetting resin layer produced on at least the outermost surface (9) or the image forming apparatus according to (10) (12) the image bearing member is characterized in that it is a photosensitive member (9) to (11) the image forming apparatus according to any one of (13) said image bearing ( 9 ) The image forming apparatus ( 14 ) according to any one of ( 9 ) to ( 12 ), characterized by comprising a charging device disposed in contact with or close to the body surface. Voltage to apply voltage with component Any one of which characterized by including a pressurized device (13) The image forming apparatus according to (15) wherein the image bearing member, characterized in that an intermediate transfer medium (9) - (9) The image forming apparatus according to ( 16 ), wherein the toner is represented by the following formula (2):

The image forming apparatus according to any one of ( 9 ) to ( 15 ), wherein the degree of circularity SR indicated by is 0.93 to 1.00.
(17) any the ratio of the weight average diameter (D4) of the toner to a number average diameter (D1) (D4 / D1) is characterized in that it is a 1.00 to 1.40 (9) - (16) the image forming apparatus according to one or.
( 18 ) at least an image carrier that has undergone a step of carrying a toner image;
In a process cartridge integrally provided with a protective layer forming apparatus for applying or adhering an image carrier protective agent to the surface of the image carrier after the toner image is transferred to a transfer medium,
A process cartridge, wherein the protective layer forming apparatus according to any one of ( 5 ) to ( 7 ) is used as the protective layer forming apparatus.
( 19 ) The process cartridge includes a cleaning device that removes toner remaining on the surface of the image carrier from the surface by rubbing against the image carrier on the upstream side of the protective layer forming device. ( 18 ) The process cartridge according to ( 18 ).
(20) in contact with the process cartridge (21) surface of the image bearing member according to the image bearing member is characterized in that it comprises a thermosetting resin layer produced on at least the outermost surface (18) or (19) ( 18 ) A process cartridge ( 22 ) according to any one of ( 18 ) to ( 20 ), further comprising a charging device disposed in the vicinity, wherein the toner includes The following formula (2)

The process cartridge according to any one of ( 18 ) to ( 21 ), wherein the circularity SR indicated by is 0.93 to 1.00.
( 23 ) The ratio (D4 / D1) between the weight average diameter (D4) and the number average diameter (D1) of the toner is 1.00 to 1.40, and any one of ( 18 ) to ( 22 ) The process cartridge according to the above.
( 24 ) An image forming apparatus comprising the process cartridge according to any one of ( 18 ) to ( 23 ).

  According to the first aspect of the present invention, the relationship between the particle size of the image carrier protecting agent and the diameter of the tip of one brush hair of the brush roller for supplying the protective layer is as follows:

By setting the relationship, it is possible to secure a stable consumption because the protective agent particles are aggregated (in a lump of particles) and do not leave the solid lubricant.

  In addition, when molding a lubricant in which fine particles are added to zinc stearate, if it is manufactured by casting molding in which a molten lubricant is filled into a mold, the molded solid becomes very hard and passes through a brush roller. There is a problem that it cannot be supplied, but by solidifying the powder by compression molding, it can be adjusted to an arbitrary strength, and a protective agent can be supplied.

According to the invention described in claims 2 to 4 , the surface of the image carrier is relatively evenly covered with a lubricant using zinc stearate as a hydrophobic organic compound, so that good protection from electrical stress in the charging step can be obtained. give. In addition, a substance with lamellar crystals has a layered structure in which amphiphilic molecules are self-assembled, and when shearing force is applied, the crystal breaks along the layers and is easy to slip, thereby improving lubricity. Can do.

According to the invention described in claims 5 to 7 , the image carrier protecting agent of the present invention exhibits a protective effect by adhering to the surface of the image carrier and forming a film. For this reason, since it is relatively easy to plastically deform, unlike the case of forming a protective layer by directly pressing a block-shaped image carrier protective agent component against the surface of the image carrier, excessive supply can be prevented, By providing a supply member between the image carrier protecting agent and the image carrier, even when a soft image carrier protecting agent is used, it is possible to uniformly supply the surface of the image carrier.

According to the invention described in claim 8, by an image forming method using a protective layer forming apparatus having the image carrier protective agent, too high lubricity between the image carrier and the cleaning member is suppressed, Polishing by the toner and its additive can be prevented. In addition, since a certain level of high lubricity is ensured, the lubricity does not deteriorate due to the effect of charging, and toner and protective agent do not slip through the cleaning member and do not fly to the charging member, thus causing contamination of the charging member. There is nothing wrong. As a result, contamination of the charging member, filming (foreign matter / adhered matter), and blade wear can be prevented at the same time.

According to the invention described in claims 9 to 17 , the image carrier can be used without being exchanged for a very long time by constituting an image forming apparatus using a protective layer forming apparatus having the image carrier protective agent. It is possible to continue. Thereby, in particular, when the image carrier includes a thermosetting resin in at least the layer formed on the outermost surface, by preventing the image carrier from being deteriorated by an electrical stress with an image carrier protective agent, The durability against mechanical stress of the image carrier including the thermosetting resin can be continuously expressed over a long period of time.

  Further, in the charging device disposed in contact with or close to the surface of the image carrier, the electrical stress tends to be large because the discharge region exists in the very vicinity of the image carrier. If the image forming apparatus of the present invention in which is formed, the image carrier can be used without being exposed to electrical stress.

  In addition, the surface of the image carrier can be made to have a very small change in surface state due to the effect of the protective layer formed, so that the quality of the cleaning changes sensitively to the state change of the image carrier. Even a toner having a large degree or a toner having a small average particle diameter can be stably cleaned over a long period of time.

  Furthermore, since the water contact angle on the surface of the image carrier can be improved and the surface of the image carrier can be kept water repellent, moisture absorption on the surface of the image carrier can be prevented and image blur can be suppressed.

According to the invention described in claims 18 to 24, by configuring the process cartridge using the protective layer forming apparatus having the image carrier protecting agent, the replacement interval of the process cartridge can be set extremely long. Therefore, the running cost is reduced and the amount of waste can be greatly reduced. For this reason, it becomes easy to reuse process cartridge components such as an image carrier and a charging member, and the amount of waste can be further reduced.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view showing an example of a protective layer forming apparatus of the present invention.
The protective layer forming devices 2, 4 and 5 disposed opposite to the photosensitive drum 1 serving as an image carrier include a hydrophobic organic compound 21, a protective material supply member 22 for the hydrophobic organic compound, a pressing member. The pressure applying mechanism 23, the protective layer forming mechanism 24, an inorganic lubricant (B) 51, a protective agent supplying member 52 for the inorganic lubricant, a pressing force applying mechanism 53, a protective layer forming mechanism 41, and the like are mainly configured. .

  In the configuration shown in FIG. 1, the protective layer forming device 4 also serves as a cleaning mechanism. That is, when the protective agent for the image carrier applied or attached to the photosensitive drum 1 as the image carrier is deteriorated, the cleaning mechanism together with the components such as the toner remaining on the image carrier by the normal cleaning mechanism. Such a cleaning mechanism may be used also as the protective layer forming member described above, but the function of removing the image carrier surface residue and the function of forming the protective layer are appropriate. Since the rubbing state of the members may be different, the functions are separated, and as shown in FIG. 1, the cleaning mechanism 4 including the cleaning member 41, the cleaning pressing mechanism 42, and the like upstream of the image carrier protective agent supply unit. Is preferably provided.

Next, in FIG. 1, the hydrophobic organic compound 21 is brought into contact with, for example, a brush-shaped protective layer forming member 22 by the pressing force from the pressing force applying mechanism 23.
The protective layer forming member 22 is arranged on the downstream side of the protective layer forming apparatus 4 that also serves as a cleaning mechanism in the rotational direction corresponding to the moving direction of the photosensitive drum 1 that is an image carrier, and is connected to the photosensitive drum 1. At this time, the hydrophobic organic compound 21 used as an image carrier protecting agent held on the surface of the protective layer forming member 22 is supplied to the surface of the image carrier.
The protective layer made of the protective material for the image carrier supplied to the surface of the photosensitive drum 1 by the protective material supply member 22 is thinned by the protective layer forming mechanism 24.

  Examples of the hydrophobic organic compound used in the present invention are classified into aliphatic saturated hydrocarbons, aliphatic unsaturated hydrocarbons, alicyclic saturated hydrocarbons, alicyclic unsaturated hydrocarbons and aromatic hydrocarbons. In addition to hydrocarbons, polytetrafluoroethylene (PTFE), polyperfluoroalkyl ether (PFA), perfluoroethylene-perfluoropropylene copolymer (FEP), polyvinylidene fluoride (PVdF), ethylene-tetrafluoro Examples thereof include fluorine resins such as ethylene copolymer (ETFE) and fluorine waxes, silicone resins such as polymethyl silicone and polymethyl phenyl silicone, and silicone waxes. Typical fatty acids from which the above fatty acid metal salts and stable hydrophobic metal salts are extracted include caproic acid, caprylic acid, enanthylic acid, pelargonic acid, undecylic acid, lauric acid, tridecoic acid, myristylic acid, Palmitic acid, margaric acid, stearic acid, non-cyclic acid, arachidic acid, behenic acid, styringic acid, palmitoleic acid, oleic acid, petricerinic acid, vaccenic acid, linoleic acid, linolenic acid, eleostearic acid, ricanin There are acids, valinal acid, gadoleic acid, arachidonic acid, whale oil and mixtures thereof. Typical stable metal salts of fatty acids include barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, cadmium stearate, magnesium stearate , Zinc stearate, zinc oleate, magnesium oleate, iron oleate, cobalt oleate, copper oleate, lead oleate, manganese oleate, zinc palmitate, cobalt palmitate, lead palmitate, magnesium palmitate, palmitate Aluminum oxide, calcium palmitate, lead caprylate, lead caprate, zinc linolenate, cobalt linolenate, calcium linolenate, zinc ricinoleate, cadmium ricinoleate and mixtures thereof There is a thing, but is not limited to this. Moreover, you may mix and use these.

The image carrier protecting agent used in the present embodiment is selected for the following reason.
When a large amount of lubricant is supplied to the surface of the image carrier, the fatty acid metal salt, which is a hydrophobic organic compound that is generally used as a protective agent, increases the amount of the lubricant that passes through the cleaning blade and soils the charging roller. On the other hand, if the supply amount is too small, the surface of the image carrier cannot be protected, and problems such as photoconductor filming occur.

  For this reason, the protective agent must constantly provide an appropriate amount of new lubricant on the surface of the image carrier. Therefore, the lubricant molded product formed into a rod shape is supplied to the image carrier through a brush.

  In addition, such a lubricant molded product is manufactured by cast molding in which a molten fatty acid metal salt is filled into a mold, and reduction of manufacturing cost and manufacturing energy due to melting is a problem. Further, in order to supply a lubricant obtained by adding fine particles or the like to a fatty acid metal salt to the surface of the image carrier through a brush, it is necessary to solidify by compression molding.

From the above viewpoint, it is necessary to stably supply the lubricant solidified by compression molding to the surface of the image carrier through the brush.
In order to stably supply a suitable amount of a lubricant obtained by solidifying a hydrophobic organic compound such as a fatty acid metal salt by compression molding to the surface of the image carrier through a brush roller over a long period of time. In the invention, the relationship of the following formula (1) is set.

  In the setting of this relationship, when the particle size of the protective agent (fatty acid metal salt) is smaller than the tip diameter of one brush hair, the particles of the protective agent are large aggregates when rubbed with a brush. As a result, it is separated from the molded product and supplied to the image carrier. The protective agent cannot be uniformly supplied to the image carrier. Furthermore, it cannot be supplied with stable consumption over a long period of time.

  On the other hand, when the tip diameter of one brush hair is larger than the particle diameter of the protective agent (fatty acid metal salt), the particle size of the protective agent (fatty acid metal salt) is larger than the tip diameter of one brush hair. Therefore, the amount rubbed by the brush is scraped off from the molded product and supplied to the image carrier. Therefore, the protective agent can be uniformly supplied to the image carrier without releasing the aggregated protective agent particles. Furthermore, the protective agent can be supplied with a stable consumption over a long period of time.

  The material of the blade used for the protective layer forming mechanism 24 is not particularly limited. For example, elastic materials such as urethane rubber, hydrin rubber, silicone rubber, and fluorine rubber, which are generally known as cleaning blade materials, may be used alone or in combination. Can be used. Further, these rubber blades may be coated or impregnated with a low friction coefficient material at the contact portion with the image carrier. Further, in order to adjust the hardness of the elastic body, fillers represented by other organic fillers and inorganic fillers may be dispersed.

  These blades are fixed to the blade support by an arbitrary method such as adhesion or fusion so that the tip can be pressed against the surface of the image carrier. The blade thickness cannot be uniquely defined in consideration of the force applied by pressing, but can be preferably used if it is about 0.5 to 5 mm, and more preferably about 1 to 3 mm.

  Further, the length of the cleaning blade that protrudes from the support and can be deflected, that is, the so-called free length, is similarly applied by pressing, and cannot be uniquely defined in terms of the force, but is generally 1 to 15 mm. If it is a grade, it can use preferably, and if it is about 2-10 mm, it can use still more preferably.

As another configuration of the blade member used in the protective layer forming mechanism 24, the surface of the elastic metal blade such as a spring plate is coated with a layer of resin, rubber, elastomer or the like through a coupling agent or a primer component if necessary. The film may be formed by a method such as dipping, heat-cured if necessary, and further subjected to surface polishing if necessary.
The thickness of the elastic metal blade is preferably about 0.05 to 3 mm, and more preferably about 0.1 to 1 mm.
Moreover, in an elastic metal blade, in order to suppress the twist of a braid | blade, you may perform processes, such as a bending process, in the direction substantially parallel to a spindle after attachment.

  As a material for forming the surface layer of the blade member, fluorine resin such as PFA, PTFE, FEP, PVdF, or silicone elastomer such as fluorine rubber or methylphenyl silicone elastomer may be used together with a filler if necessary. Yes, but not limited to this.

  Further, the force that presses the photosensitive drum 1 that is the image carrier by the protective layer forming mechanism 24 is sufficient as the force that the image carrier protective agent spreads to form a protective layer or a protective film, and the linear pressure is 5 gf. / Cm or more and 80 gf / cm or less is preferable, and 10 gf / cm or more and 60 gf / cm or less is more preferable.

  A brush-like member is preferably used as the protective layer forming member 22. In this case, it is preferable that the brush fibers have flexibility in order to suppress mechanical stress on the surface of the image carrier.

  As a specific material of the flexible brush fiber, one or more kinds can be selected and used from generally known materials. Specifically, polyolefin resins (eg, polyethylene, polypropylene); polyvinyl and polyvinylidene resins (eg, polystyrene, acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, and Polyvinyl chloride); vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; styrene-butadiene resin; fluorine resin (for example, polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene); Polyester; Nylon; Acrylic; Rayon; Polyurethane; Polycarbonate; Phenol resin; Amino resin (eg urea-formaldehyde resin, melamine) Fat, benzoguanamine resins, urea resins, polyamide resins); Among such, may be a resin having flexibility.

  In order to adjust the degree of bending, diene rubber, styrene-butadiene rubber (SBR), ethylene propylene rubber, isoprene rubber, nitrile rubber, urethane rubber, silicone rubber, hydrin rubber, norbornene rubber, etc. may be used in combination. .

In FIG. 1, the support for the protective layer forming members 22 and 52 includes a fixed mold and a rotatable roll. As the roll-shaped supply member, for example, there is a roll brush in which a tape having brush fibers piled is wound around a metal core in a spiral shape. The brush fiber has a fiber diameter of about 10 to 500 μm, the length of the brush fiber is 1 to 15 mm, and the brush density is 10,000 to 300,000 per square inch (1.5 × 10 ^{7 to} 4.5 × 10 per square meter). ⁸ ) are preferably used.

  The protective layer forming member 22 is preferably made of a material having a very high brush density in terms of supply uniformity and stability, and one fiber is made from several to several hundreds of fine fibers. It is also preferable. For example, bundling 50 fine fibers of 6.7 decitex (6 denier), such as 333 decitex = 6.7 decitex × 50 filament (300 denier = 6 denier × 50 filament), and implanting as one fiber Is also possible.

  Moreover, you may provide a coating layer in the brush surface for the purpose of stabilizing the surface shape of a brush, environmental stability, etc. as needed. As a component constituting the coating layer, it is preferable to use a coating layer component that can be deformed according to the bending of the brush fiber, and these are not limited as long as the material can maintain flexibility. Polyolefin resins such as polyethylene, polypropylene, chlorinated polyethylene, chlorosulfonated polyethylene, etc .; polystyrene, acrylic (for example, polymethyl methacrylate), polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, Polyvinyl and polyvinylidene resins such as polyvinyl carbazole, polyvinyl ether, and polybiliketones; vinyl chloride-vinyl acetate copolymers; silicone resins composed of organosiloxane bonds or modified products thereof (for example, alkyd resins, Modified products by reester resin, epoxy resin, polyurethane, etc.); Fluororesin such as perfluoroalkyl ether, polyfluorovinyl, polyfluorovinylidene, polychlorotrifluoroethylene; polyamide; polyester; polyurethane; polycarbonate; urea-formaldehyde resin, etc. Amino resins; epoxy resins, composite resins of these, and the like.

  An example of an image forming apparatus provided with the above-described protective layer forming apparatus is shown in FIG.

  An image forming apparatus 100 shown in FIG. 2 is a tandem type color printer in which a plurality of image forming stations capable of forming different color images are juxtaposed along the extended surface of an intermediate transfer body 60 used in the transfer apparatus.

  The image forming apparatus 100 includes a protective layer forming device 2, a charging device 3, a latent image forming device 8, a developing device 50, a transfer device 6, and a cleaning device around drum-shaped image carriers 1Y, 1M, 1C, and 1K, respectively. The apparatus 4 is arranged, and image formation is performed by the following operation.

Hereinafter, a series of processes for image formation will be described with a negative-positive process.
An image carrier represented by a photoconductor (OPC) having an organic photoconductive layer is neutralized by a neutralizing lamp (not shown) or the like, and is uniformly negatively charged by a charging device 3 having a charging member.

  The photoreceptor used in the present invention is provided with an outermost surface layer, and improves the mechanical strength, abrasion resistance, gas resistance, cleaning property and the like of the photoreceptor. As the outermost surface layer, a polymer having a mechanical strength higher than that of the photosensitive layer and a material in which an inorganic filler is dispersed in the polymer are suitable. The resin used for the outermost surface layer may be either a thermoplastic resin or a thermosetting resin, but the thermosetting resin has high mechanical strength and suppresses abrasion due to friction with the cleaning blade. This is particularly preferable because of its extremely high capacity. If the surface layer is thin, there is no problem even if it does not have the charge transport capability, but if the surface layer without the charge transport capability is formed thick, the sensitivity of the photoreceptor decreases, the potential increases after exposure, and the residual layer Since the potential rise is likely to occur, it is preferable to include the above-described charge transport material in the surface layer or to use a polymer having charge transport ability as the polymer used in the surface layer.

  When the image carrier is charged by the charging device, an appropriate voltage suitable for charging the image carriers 1Y, 1M, 1C, and 1K to a desired potential from a voltage application mechanism (not shown) to the charging member. A large voltage or a charging voltage obtained by superimposing an AC voltage thereon is applied.

  The charged image carriers 1Y, 1M, 1C, and 1K form a latent image with a laser beam irradiated by a latent image forming device 8 such as a laser optical system (the absolute value of the exposed portion potential is the absolute value of the non-exposed portion potential). Is lower than the value).

  Laser light is emitted from a semiconductor laser, and the surfaces of the image carriers 1Y, 1M, 1C, and 1K are scanned in the direction of the rotation axis of the image carrier by a polygonal polygonal mirror (polygon) that rotates at high speed.

  The latent image formed in this way is described in detail in FIG. 3, but is formed from toner particles or a mixture of toner particles and carrier particles supplied onto a developing sleeve 50 </ b> A that is a developer carrier in the developing device 50. A toner visible image is formed by developing with the developer. In FIG. 3, reference numeral 50A denotes a developing sleeve, and reference numerals 50B and 50C denote stirring transport members.

  At the time of developing the latent image, a voltage of an appropriate magnitude or a voltage between the exposed portion and the non-exposed portion of the image carrier 1Y, 1M, 1C, 1K is applied to the developing sleeve from a voltage application mechanism (not shown). A developing bias superimposed with an AC voltage is applied.

  In the present invention, the toner used for development has the following characteristics.

  The toner preferably has an average circularity of 0.93 to 1.00, more preferably 0.95 to 0.99, which is an average value of the circularity SR represented by the following formula (2). This average circularity is an index of the degree of unevenness of toner particles, and indicates 1.00 when the toner is a perfect sphere, and the average circularity becomes smaller as the surface shape becomes more complicated.

  When the average circularity is in the range of 0.93 to 1.00, the surface of the toner particles is smooth, and the toner particles and the contact area between the toner particles and the photosensitive member are small, so that the transferability is excellent. Further, since the toner particles have no corners, the developer agitation torque in the developing device is small, and the agitation drive is stabilized, so that no abnormal image is generated. In addition, since there are no angular toner particles in the toner that forms the dots, the pressure is uniformly applied to the entire toner that forms the dots when pressed against the recording medium during transfer, and the transfer is not easily lost. Further, since the toner particles are not angular, the abrasive power of the toner particles themselves is small, and the surface of the image carrier is not damaged or worn.

  The circularity SR can be measured using, for example, a flow particle image analyzer (manufactured by Toa Medical Electronics Co., Ltd., FPIA-1000).

  First, 0.1 to 0.5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance. Add ~ 0.5g. The suspension in which the sample is dispersed is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the shape and particle size of the toner are measured by the above apparatus with a dispersion concentration of 3000 to 10000 / μl (liter).

  The toner has a mass average particle diameter (D4) of preferably 3 to 10 μm, and more preferably 4 to 8 μm. In this range, since the toner particles have a sufficiently small particle size with respect to the minute latent image dots, the dot reproducibility is excellent. When the mass average particle diameter (D4) is less than 3 μm, phenomena such as a decrease in transfer efficiency and a decrease in blade cleaning properties may occur, and when it exceeds 10 μm, it is difficult to suppress scattering of characters and lines. is there.

  The toner has a mass average particle diameter (D4) to number average particle diameter (D1) ratio (D4 / D1) of preferably 1.00 to 1.40, and more preferably 1.00 to 1.30. The closer the ratio (D4 / D1) is to 1, the sharper the particle size distribution of the toner. In the range of (D4 / D1) from 1.00 to 1.40, selective development depending on the toner particle size. Since image quality does not occur, the image quality is excellent. In addition, since the toner particle size distribution is sharp, the triboelectric charge amount distribution is also sharp and the occurrence of fog is suppressed. Further, when the toner particle diameter is uniform, the latent image dots are developed so as to be arranged densely and orderly, so that the dot reproducibility is excellent.

  Here, the mass average particle diameter (D4) and the particle size distribution of the toner are measured by, for example, a Coulter counter method. Examples of the measuring device for the particle size distribution of toner particles by the Coulter counter method include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter).

  First, 0.1 to 5 ml of a surfactant (preferably alkyl benzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as the aperture. Volume distribution and number distribution are calculated. From the obtained distribution, the mass average particle diameter (D4) and the number average particle diameter (D1) of the toner can be obtained.

  As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

  As the toner having such a substantially spherical shape, a toner composition containing a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent is crosslinked in the presence of resin fine particles in an aqueous medium. It can be prepared by an extension reaction. The toner produced by this reaction can reduce the hot offset by curing the toner surface, and can prevent the fixing device from becoming dirty and appearing on the image.

The toner images formed on the image carriers 1Y, 1M, 1C, and 1K corresponding to the respective colors are transferred onto the intermediate transfer member 60 by the primary transfer device 6A facing the image carrier with the intermediate transfer member 60 interposed therebetween. The toner image is transferred by the transfer device 6 onto a recording medium such as paper fed from the paper feeding mechanism 200.
At this time, it is preferable that a potential having a polarity opposite to the polarity of toner charging is applied to the transfer device 6 as a transfer bias. Thereafter, the intermediate transfer member 60 is separated from the image carrier to obtain a transfer image.
Further, the toner particles remaining on the image carrier are collected by the cleaning member into the toner collecting chamber in the cleaning device 4.

  As the image forming apparatus, an apparatus in which a plurality of the developing devices described above are arranged is used, and a plurality of toner images, which are sequentially produced by the plurality of developing devices, are sequentially transferred onto a transfer material, and then sent to a fixing mechanism to be heated. Even after a plurality of toner images prepared in the same manner are sequentially sequentially transferred onto an intermediate transfer member and then transferred to a recording medium such as paper, Similarly, a fixing device may be used.

  The charging device 3 is preferably a charging device arranged in contact with or close to the surface of the image carrier, and a discharge wire is used. This makes it possible to significantly suppress the amount of ozone generated during charging as compared with a corona discharger that corresponds to a so-called corotron or scorotron type.

  In a charging device that charges such a charging member in contact with or close to the surface of the image carrier, as described above, the discharge is performed in a region near the surface of the image carrier, so that electrical stress is applied to the image carrier. Tends to grow. However, by using the protective layer forming apparatus using the protective agent for an image carrier of the present invention, the image carrier can be maintained for a long time without deterioration. Fluctuations can be greatly suppressed, and stable image quality can be ensured.

  As described above, the image forming apparatus of the present invention has an excellent tolerance for fluctuations in the surface state of the image carrier, particularly the presence of a low resistance portion, and highly suppresses fluctuations in the charging performance of the image carrier. Therefore, when used in combination with the toner having the above-described configuration, an extremely high-quality image can be stably formed over a long period of time.

On the other hand, each image forming station is equipped with a process cartridge described later.
The image forming apparatus using the protective layer forming apparatus of the present invention is equipped with a process cartridge in each image forming unit.
The process cartridge includes at least an image carrier and the protective layer forming unit of the present invention, and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a discharging unit, and the like as necessary. It has the means of.

  The process cartridge of the present invention can be detachably provided in various electrophotographic apparatuses, and is preferably provided detachably in the above-described image forming apparatus of the present invention.

FIG. 3 is a schematic view for explaining an outline of a process cartridge configuration example using the protective layer forming apparatus of the present invention.
In FIG. 3, the process cartridge includes a protective layer forming apparatus 2 disposed opposite to the photosensitive drum 1 that is an image carrier, and includes an image carrier protective agent 21, a protective layer forming member 22, and a pressing force applying member. 23, the protective layer forming member 24 and the like.

  Further, the image carrier (indicated by reference numeral 1 for convenience) has a surface on which the protective agent for the image carrier and the toner component partially deteriorated after the transfer process remain, but is provided in the cleaning device 4. The remaining surface is cleaned and cleaned by the cleaning member 41.

  In FIG. 3, the cleaning member is abutted at an angle similar to a so-called counter type (leading type).

  From the protective layer forming member 22 intended for the hydrophobic organic compound, the image carrier protective agent is applied to the surface of the image carrier from which the residual toner on the surface and the deteriorated protective agent for the image carrier are removed by the cleaning mechanism. 21 is supplied, and the protective layer forming member 24 forms a film-like protective layer. At this time, the protective agent for the image carrier used in the present invention has a better adsorptivity to the portion of the surface of the image carrier that is highly hydrophilic due to electrical stress. Even if a large electrical stress is applied and the surface of the image carrier starts to deteriorate partially, the progress of the deterioration of the image carrier itself can be prevented by adsorption of the protective agent.

  The image bearing member thus formed with the protective layer is charged, and then an electrostatic ray image is formed by exposure L such as a laser, developed by the developing device 50 to be visualized, and a transfer roller outside the process cartridge. 6 or the like.

As described above, the process cartridge of the present invention has an excellent tolerance for fluctuations in the surface state of the image carrier, particularly the presence of a low-resistance portion, and has a configuration in which fluctuations in charging performance to the image carrier are highly suppressed. Therefore, when used in combination with the toner having the above structure, an extremely high quality image can be stably formed over a long period of time.
(Example)
Examples of experiments using the image carrier protecting agent according to the present invention are as follows.
In the experiment, the protective layer forming apparatus shown in FIG. 1 was installed on the image forming unit of imgio MP3000 manufactured by Ricoh Co., Ltd., and an image carrier protective agent by compression molding was applied to the photosensitive drum 1. It was broken.

Table 1 and FIG. 4 are diagrams showing a comparison result between a result of applying a protective agent containing a hydrophobic organic compound by compression molding and a comparative example with respect to the example.
The conditions under which the results shown in Table 1 were obtained are as follows. In addition, the tip diameter of one brush hair was measured under the condition of an acceleration voltage of 3 KV using the SEM (JEOL Electrolytic Radiation Scanning Electron Microscope JSM-7400F).

As an image carrier protecting agent in Comparative Examples and Examples, zinc stearate, one of fatty acid metal salts, was used as a hydrophobic organic compound.
The average particle diameter of the protective agent was a value of D50 using a laser diffraction particle size distribution analyzer SALD-2200 (manufactured by Shimadzu Corporation).

In Comparative Example 1 and Examples 1-3, a brush roller having a tip diameter of one brush hair of 20 μm is used. In Comparative Examples 2, 3, and 3, a brush having a tip diameter of one brush hair of 100 μm is used. A roller was used.
Example 1
As the image carrier protective agent, a protective agent obtained by compression-molding a hydrophobic organic compound having an average particle diameter of 20 μm was used, and a protective layer supplying brush roller having a tip diameter of 20 μm was used. The relationship represented by the equation (1) at this time is as follows.
The average particle diameter of the image carrier protective agent is 20 μm ≧ the diameter of the tip of one protective layer supplying brush hair is 20 μm.
(Example 2)
As the image carrier protective agent, a protective agent obtained by compression molding a hydrophobic organic compound having an average particle diameter of 90 μm was used, and a brush roller for supplying a protective layer having a diameter of 20 μm at the tip of one brush hair was used. The relationship represented by the equation (1) at this time is as follows.
The average particle size of the image carrier protective agent is 90 μm ≧ the diameter of the tip of one brush for supplying the protective layer is 20 μm.
(Example 3)
As the image carrier protective agent, a protective agent obtained by compression-molding a hydrophobic organic compound having an average particle size of 300 μm was used, and a brush roller for supplying a protective layer having a diameter of 20 μm at the tip of one brush hair was used. The relationship represented by the equation (1) at this time is as follows.
The average particle diameter of the protective agent for the image carrier 300 μm ≧ the diameter of the tip of one protective layer supply brush hair 20 μm
Example 4
As the image carrier protective agent, a protective agent obtained by compression-molding a hydrophobic organic compound having an average particle diameter of 300 μm was used, and a protective layer supplying brush roller having a tip of one brush hair having a diameter of 100 μm was used. The relationship represented by the equation (1) at this time is as follows.
The average particle size of the image carrier protecting agent is 300 μm ≧ the diameter of the tip of one brush for supplying the protective layer is 100 μm.
On the other hand, in Comparative Example 1 for Examples, a protective agent obtained by compression-molding a hydrophobic organic compound having an average particle diameter of 10 μm is used as the image carrier protective agent, and the diameter of the tip of one brush hair is 20 μm. A layer supply brush roller was used. The relationship at this time is as follows.
Average particle size of protective agent for image carrier 10 μm ≦ diameter 20 μm at the tip of one brush for supplying protective layer
In Comparative Example 2, a protective layer supply brush roller in which a protective agent obtained by compression-molding a hydrophobic organic compound having an average particle diameter of 20 μm is used as the image carrier protective agent, and the diameter of one brush bristle tip is 100 μm. It was used. The relationship at this time is as follows.
Average particle diameter of the image carrier protective agent 90 μm ≦ the diameter of the tip of one brush hair of the protective layer supply 100 μm
For each of the above-mentioned protective agents, a continuous paper passing test of 5,000 sheets each of A4 size and 6% image area ratio was performed twice.
Before and after the continuous paper feeding test, the weight of the protective agent was measured with a precision electronic balance, and the consumption of the protective agent was calculated. Further, the result of visual determination of the contamination state of the charging roller is the result shown in Table 1 and FIG.

It is the schematic which shows an example of the protective layer formation apparatus of this invention. 1 is a schematic diagram illustrating an example of an image forming apparatus of the present invention. It is the schematic which shows an example of the process cartridge of this invention. It is a figure which shows the result of having experimented on the relationship between the particle size in the protective agent used for the protective layer forming apparatus of this invention, and the front-end | tip diameter of one brush hair.

Explanation of symbols

1 Image carrier (photosensitive drum)
DESCRIPTION OF SYMBOLS 2 Protective layer forming apparatus 3 Charging roller 4 Cleaning mechanism 5 Developing apparatus 6 Transfer roller 8 Latent image forming apparatus 21 Inorganic lubricant used as one of protective materials for image carrier 22 Protective layer forming member 23 Pressure applying member 24 Protective layer forming member 41 Cleaning member 42 Cleaning pressing member 60 Intermediate transfer member 100 Image forming apparatus 200 Paper feed mechanism L Exposure

Claims (24)

An image carrier protecting agent used to form a protective layer on the surface of the image carrier by applying or adhering to the surface of the image carrier by a brush roller disposed opposite to the surface of the image carrier. And
The image carrier protective agent is added to the fatty acid metal salt by adding fine particles or the like and solidified by compression molding. When the tip diameter per brush hair of the brush roller is 10 to 500 μm , the following formula ( 1)

An image carrier protecting agent, wherein the relationship is established. The image carrier protecting agent according to claim 1, wherein the image carrier protecting agent contains a hydrophobic organic compound . The protective agent for an image carrier according to claim 1 or 2, wherein the hydrophobic organic compound used for the image carrier is a metal salt of a fatty acid . A method for forming a protective layer using the image carrier protective agent according to any one of claims 1 to 3, wherein a substance having a lamellar crystal is used as a hydrophobic organic compound used in the image carrier protective agent. A method for forming a protective layer . A protective layer forming apparatus for forming a protective layer using the image carrier protective agent according to any one of claims 1 to 3,
An apparatus for forming a protective layer, wherein the protective layer is formed by applying or adhering the image carrier protective agent to the surface of the image carrier. 6. The protective layer forming apparatus according to claim 5 , wherein the image carrier protecting agent is supplied to the surface of the image carrier through a supply member . 7. The protective layer forming apparatus according to claim 5 , further comprising a layer forming member that presses the image carrier protective agent supplied to the surface of the image carrier to form a film . At least an image carrier through which a toner image is carried; and
  Transfer means for transferring the toner image on the image carrier to a transfer medium;
  In an image forming method using a protective layer forming means for applying or adhering an image carrier protective agent to the surface of the image carrier after the toner image is transferred to a transfer medium,
  An image forming method comprising using the image carrier protecting agent according to claim 1 as the image carrier protecting agent. At least an image carrier through which a toner image is carried; and
A transfer device for transferring the toner image on the image carrier to a transfer medium;
In an image forming apparatus comprising a protective layer forming device for applying or adhering an image carrier protective agent to the surface of the image carrier after the toner image is transferred to a transfer medium,
An image forming apparatus using the protective layer forming apparatus according to claim 5 as the protective layer forming apparatus. A cleaning device is provided on the downstream side of the transfer device and the upstream side of the protective layer forming device to remove toner remaining on the surface of the image carrier from the surface by rubbing against the image carrier. the image forming apparatus according to claim 9, characterized in. The image forming apparatus according to claim 9, wherein the image carrier includes a thermosetting resin in at least a layer formed on the outermost surface . The image forming apparatus according to claim 9, wherein the image carrier is a photoconductor . The image forming apparatus according to claim 9, further comprising a charging device disposed in contact with or close to the surface of the image carrier. The image forming apparatus according to claim 13 , wherein the charging device includes a voltage applying device that applies a voltage having an AC component. The image forming apparatus according to claim 9, wherein the image carrier is an intermediate transfer medium . The toner is represented by the following formula (2)

The image forming apparatus according to any one of claims 9 to 15 , wherein a degree of circularity SR represented by the formula is 0.93 to 1.00 . The ratio (D4 / D1) of the weight average diameter (D4) to the number average diameter (D1) of the toner is 1.00 to 1.40, according to any one of claims 9 to 16. Image forming apparatus. At least an image carrier through which a toner image is carried; and
In a process cartridge integrally provided with a protective layer forming apparatus for applying or adhering an image carrier protective agent to the surface of the image carrier after the toner image is transferred to a transfer medium,
A process cartridge, wherein the protective layer forming apparatus according to claim 5 is used as the protective layer forming apparatus . The process cartridge includes a cleaning device that removes toner remaining on the surface of the image carrier from the surface upstream of the protective layer forming device by rubbing against the image carrier. The process cartridge according to claim 18 . 20. The process cartridge according to claim 18, wherein the image carrier includes a thermosetting resin in at least a layer formed on the outermost surface . 21. The process cartridge according to claim 18, further comprising a charging device disposed in contact with or close to the surface of the image carrier. A container containing toner, wherein the toner is represented by the following formula (2)

The process cartridge according to any one of claims 18 to 21 , wherein the circularity SR indicated by the formula is 0.93 to 1.00 . According to any one of claims 18 to 22 in which the ratio of the weight average particle diameter (D4) of the toner to a number average diameter (D1) (D4 / D1) is characterized in that it is a 1.00 to 1.40 Process cartridge. An image forming apparatus comprising the process cartridge according to claim 18 .

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