JP4965217B2 - Image forming apparatus - Google Patents

Description

The present invention relates to an image forming apparatus using an electrophotographic direction, and more particularly relates to an image forming equipment having a charging member for charging by the proximity discharge ZoTanji body.

  An image forming apparatus using an electrophotographic process includes a photoconductor as an image carrier, and charges the surface of the photoconductor by discharging to form an electrostatic latent image by exposing the charged photoconductor surface. A toner is supplied to the electrostatic latent image to make it visible, and the visible image formed on the surface of the photoreceptor is transferred onto the surface of the transfer paper, and then fixed and discharged. Since untransferred toner or the like remains on the surface of the photoconductor after the transfer of the visible image, the photoconductor surface is cleaned by a cleaning device so that they do not adversely affect the next image formation. Be prepared for the forming process. As a cleaning device, a cleaning blade made of an elastic material such as rubber or a cleaning brush in which synthetic resin fibers are formed in a brush shape is rubbed against the surface of the photosensitive member to remove deposits such as untransferred toner. Known.

  However, the cleaning blade and the cleaning brush as described above have a problem that if the rubbing with the photosensitive member is continued, the cleaning blade and the cleaning brush are worn over time and the cleaning performance is deteriorated. In addition, the surface of the photoconductor also decreases in thickness due to wear and reaches the end of its life. Therefore, in order to reduce the frictional resistance acting between the photosensitive member and these cleaning members and extend the life of the cleaning member and the photosensitive member, a technique such as applying a lubricant to the surface of the photosensitive member is employed. . Also, if a lubricant is applied to the surface of the photoconductor, the coefficient of friction on the surface of the photoconductor decreases, so that a fluidizing agent or a charge control agent added to the toner is applied to the surface of the photoconductor by the contact pressure with the cleaning member. It is possible to prevent so-called filming that is fixed in a film form. Transferability of the toner developed on the photoreceptor is also improved by reducing the adhesive force with the surface of the photoreceptor.

  On the other hand, a charging method in which a small gap is formed between the photosensitive member and the charging roller and is used for proximity discharge is generally used because it can obtain a small and uniform charge. It has become clear that the surface of the image carrier is chemically deteriorated by direct exposure to proximity discharge to promote wear of the image carrier. In order to prevent chemical deterioration due to this proximity discharge, it has been found that it is effective to uniformly apply a lubricant such as zinc stearate to the surface of the image carrier (see, for example, Patent Document 1). . In order to apply the lubricant to the image carrier, as described in Patent Document 1, it is common to apply the cleaning blade after applying the lubricant to the image carrier with a fur brush that abuts the lubricant.

  By forming a uniform protective film on the photoreceptor, chemical deterioration due to proximity charging can be reduced and the life of the photoreceptor can be extended. However, if the amount of lubricant applied is too large or unevenly applied, the surface of the charging roller that is close to or in contact with the surface of the photoreceptor will be contaminated, or the lubricant will absorb moisture in a high-temperature, high-humidity environment. As a result, an electrostatic latent image formed on the surface of the photoconductor flows and causes image blurring. Therefore, it is important to uniformly apply an appropriate amount of lubricant to the surface of the photoreceptor. In the lubricant application device, the fiber density of the brush roller for applying the lubricant is specified, the pressure application member for pressing the solid lubricant to the brush roller side is provided, the pressure is specified, the brush roller Proposals have been made to specify the amount of biting into the surface of the photoreceptor (see, for example, Patent Document 2).

  By the way, in recent years, a demand for higher image quality has been increasing, and in order to realize particularly high-definition color image formation, toner particle diameters and spheroidization have been promoted. The reproducibility of dots is improved by reducing the particle size, and the developability and transferability can be improved by making the particles spherical. Since it is very difficult to produce such a small particle size and spherical toner by the conventional kneading and pulverization method, the polymerization produced by suspension polymerization method, emulsion polymerization method, dispersion polymerization method, etc. Toner is being adopted.

  In addition, an organic photoreceptor has been used as the photoreceptor because it is inexpensive. Polycarbonate resins, acrylic resins, and the like have been put to practical use as resins that form organic photoreceptors. However, when these resins are used for the surface layer, the surface layer gradually wears by repeated use, so the life is short. Therefore, in order to increase the durability of the photosensitive member, a surface layer containing a filler such as titanium oxide or alumina has been studied (for example, see Patent Document 3). In addition, it has been studied to use a resin obtained by curing a compound having a chain polymerizable functional group on the surface layer by polymerization or crosslinking (see, for example, Patent Document 4). In particular, an image carrier using a curable resin not only has excellent durability against abrasion by forming a surface layer with high hardness, high elasticity and uniformity, but also foreign matter such as toner and toner additives. It has a very high margin and high reliability with respect to a problem called filming that forms an abnormal image by adhering to the surface of the carrier as a thin film.

JP 2004-341480 A Japanese Patent Laid-Open No. 10-260614 JP 2002-341571 A JP 2004-302450 A

However, several problems occur when these toners and photoconductors are used.
First, spheroidization. When toner having a reduced particle size is used, there are some problems in cleaning on the photoreceptor after image formation. This means that it is difficult to clean the toner having a reduced particle size by using a blade cleaning method generally used. The cleaning blade removes toner while rubbing the surface of the photoconductor, but the edge portion of the cleaning blade is deformed due to frictional resistance with the photoconductor, so that a minute space is generated between the photoconductor and the cleaning blade. The smaller the toner particle size, the easier it is to enter this space. Since the rolling friction force is smaller as the invading toner has a shape close to a spherical shape, it starts to roll in the space between the photosensitive member and the cleaning blade, passes through the cleaning blade, and leads to poor cleaning. As a measure to prevent such a cleaning failure, it has become more important to uniformly apply a lubricant to the surface of the photoreceptor and reduce the coefficient of friction on the surface of the photoreceptor, but the amount of lubricant applied is too large. And the surface of the charging roller that is close to or in contact with the surface of the photoreceptor, it is difficult to control an appropriate amount.

Further, when a curable resin is used for the surface layer of the photosensitive member, the wear life of the photosensitive member becomes long, but there is a problem that the sliding property with the blade is very poor. The minute unevenness on the surface of the image carrier greatly contributes to the sliding property with the blade. The sliding property of the blade is poor for a smooth curable resin with little surface unevenness, and the edge of the blade is It will be drawn in the direction of rotation. It is necessary to apply the lubricant uniformly and at the same time to appropriately roughen the surface of the photoreceptor to improve the sliding property of the blade. In addition, since the photoconductor is hard, there is a possibility of developing problems such as filming unless the deposits on the photoconductor are properly removed. For these purposes, brushes do not work well with fine fibers.
The structure required for the brush is different for the purpose of removing toner and deposits on the photoreceptor and for the purpose of properly applying the lubricant.

  SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a process cartridge and an image forming apparatus provided with a brush capable of performing both proper application of a lubricant on a photoconductor and cleaning of the surface of the photoconductor. And In addition to improving the cleanability of the surface of the photoconductor and applying an appropriate lubricant uniformly, the photoconductor is protected from electrical stress in the charging process, and the life of the photoconductor and the charging member is extended. Provided are an image forming apparatus and a process cartridge that stably output quality images over a long period of time.

According to the first aspect of the present invention, at least an image carrier on which a toner image is carried and conveyed, and a charging member which is provided at a position close to or in contact with the surface of the image carrier and charges the surface of the image carrier by proximity discharge An image forming apparatus comprising: a cleaning member that contacts the image carrier; and a lubricant application unit that applies a lubricant to the surface of the image carrier. The lubricant application unit includes a solid lubricant and a brush roller. The brush roller is composed of two types of fibers having different bristle lengths, and the longer fiber of the brush roller is in contact with both the lubricant and the image carrier while the bristle It is set so that the fiber of the shorter foot does not contact the lubricant but only the image carrier, and the wire diameter of the longer fiber of the bristle is thinner than that of the shorter fiber. Features.
According to a second aspect of the present invention, at least an image carrier on which a toner image is carried and conveyed, and a charging member which is provided at a position close to or in contact with the surface of the image carrier and charges the surface of the image carrier by proximity discharge An image forming apparatus comprising: a cleaning member that contacts the image carrier; and a lubricant application unit that applies a lubricant to the surface of the image carrier. The lubricant application unit includes a solid lubricant and a brush roller. The brush roller is composed of two types of fibers having different bristle lengths, and the longer fiber of the brush roller is in contact with both the lubricant and the image carrier while the bristle The fiber of the shorter foot is not in contact with the lubricant, but only in contact with the image carrier, and the elastic coefficient of the longer fiber of the bristle is smaller than that of the shorter fiber. Features.

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the shorter fiber of the bristle is formed in a loop shape .
According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the fibers having longer hairs are implanted obliquely with respect to the longitudinal direction of the roller shaft. and said that you are.

According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the brush roller includes a plurality of strip-like sheets having different fiber lengths arranged in a spiral shape on the cored bar. It is characterized by a wound configuration .
According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the lubricant is a metal soap .

According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the lubricant comprises a hydrophobic organic compound (A) and an amphiphilic organic compound (B). It is characterized by including .
According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, the image carrier has a protective layer made of a cross-linking curable resin as a surface layer .

  According to the present invention, deposits on the photosensitive member can be removed while applying the lubricant in an appropriate amount and state in order to maintain the cleaning ability on the image carrier. Thereby, the surface of the image carrier can be maintained in a good state for a long time. Lubricant agglomerates do not remain on the photoconductor, so that the lubricant itself does not stain the charging roller or form a film on the photoconductor, resulting in abnormal images and stable high-quality images. Can be provided.

FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus to which the present invention is applied.
In the figure, reference numeral 1 is a photosensitive member, 9 is an exposure device, 51 is a primary transfer roller, 52, 53 and 54 are rollers, 56 is an intermediate transfer belt, 57 is an intermediate transfer belt cleaning device, 61 is a secondary transfer roller, 71 Denotes a fixing belt, 72 denotes a heating roller, 73 denotes a fixing roller, and 74 denotes a pressure roller. Y, M, C, and K are subscripts indicating colors.
The image forming apparatus includes an intermediate transfer belt 56 in the approximate center of the inside thereof. The intermediate transfer belt 56 is an endless belt made of a heat-resistant material such as polyimide or polyamide, and a base body adjusted to a medium resistance. The intermediate transfer belt 56 is supported by being wound around four rollers 52, 53, and 54. It is rotationally driven in the direction. Above the intermediate transfer belt 56, four image forming units corresponding to yellow (Y), magenta (M), cyan (C), and black (K) toners are arranged along the belt surface of the intermediate transfer belt 56. It is out.

FIG. 2 is an enlarged view showing one of the four image forming units.
In the figure, reference numeral 2 denotes a charging device, 3 denotes a lubricant application device, 4 denotes a developing device, and 8 denotes a cleaning device.
Since any image forming unit has the same configuration, Y, M, C, and K indicating color distinction are omitted in this figure. Each image forming unit has a photoreceptor 1, and around each photoreceptor 1, a charging device 2 that applies a charge to the surface of the photoreceptor 1, and a latent image formed on the surface of the photoreceptor 1 is developed with each color toner. A developing device 4 for forming a toner image, a lubricant applying device 3 for applying a lubricant to the surface of the photoreceptor 1, and a cleaning device 8 for cleaning the surface of the photoreceptor 1 after the toner image transfer are arranged.
Referring to FIG. 1, an exposure device 9 is provided above the four image forming units to expose the surface of each charged photoconductor based on the image data of each color to form a latent image. .
A primary transfer roller 51 that primarily transfers a toner image formed on the photoconductor 1 onto the intermediate transfer belt 56 is disposed at a position facing each photoconductor 1 with the intermediate transfer belt 56 interposed therebetween. The primary transfer roller 51 is connected to a power source (not shown) and is applied with a predetermined voltage.

A secondary transfer roller 61 is pressed against the outside of the portion of the intermediate transfer belt 56 supported by the roller 52. The secondary transfer roller 61 is connected to a power source (not shown) and is applied with a predetermined voltage. A contact portion between the secondary transfer roller 61 and the intermediate transfer belt 56 is a secondary transfer portion, and the toner image on the intermediate transfer belt 56 is transferred onto a transfer sheet.
An intermediate transfer belt cleaning device 57 for cleaning the surface of the intermediate transfer belt 56 after the secondary transfer is provided outside the portion of the intermediate transfer belt 56 supported by the roller 53.
A fixing device 70 for fixing the toner image on the transfer paper to the transfer paper semi-permanently is provided downstream of the secondary transfer unit. The fixing device 70 includes a heating roller 72 having a halogen heater therein and an endless fixing belt 71 wound around the fixing roller 73, and a pressurization disposed so as to face and press the fixing roller 73 via the fixing belt 71. And a roller 74.

Hereinafter, the features of the image forming apparatus will be described in more detail.
The photoreceptor 1 is an organic photoreceptor, and a surface protective layer is formed of a polycarbonate-based resin.
The charging device 2 includes a charging roller 2a configured by covering a conductive cored bar with a medium resistance elastic layer as a charging member. The charging roller 2 a is disposed with a small gap with respect to the photoreceptor 1. The minute gap is set by, for example, winding a spacer member having a certain thickness around the non-image forming regions at both ends of the charging roller 2a to bring the surface of the spacer member into contact with the surface of the photoreceptor 1. can do. Further, the charging roller 2a is provided with a charging cleaning member 2b for cleaning in contact with the surface of the charging roller 2a.
The charging roller 2a used in the present invention is of a type in which the surface of the photosensitive member is charged by causing proximity discharge by being placed in contact or non-contact proximity to the photosensitive member.
In the above, contact means that the charging roller is in direct contact with the photosensitive member, and non-contact proximity means that a gap of 200 μm or less exists between the photosensitive member and the charging roller. The non-contact proximity method has an advantage that the surface of the charging member is hardly contaminated by toner remaining on the surface of the photosensitive member.

The charging roller is made of, for example, epichlorohydrin rubber on the outer periphery of a metal core that is, for example, a metal shaft having an outer diameter of 8 mm formed by SUM-Ni plating (steel surface is nickel-plated), and has a volume resistivity of 1 × 10 ^3. The elastic roller portion having a thickness of ˜1 × 10 ⁸ Ω · cm is formed as a layer having a thickness of 1.5 mm, for example. Furthermore, the elastic roller part uses that whose test piece hardness of rubber itself is 60 degrees, for example. Further, specific examples of the charging roller 2a having a hard surface include, for example, a thermoplastic resin composition (polyethylene, polypropylene, polymethyl methacrylate, polystyrene, and their co-polymers) in which a polymer ion conductive agent is dispersed in a resistance adjustment layer. And the like, and the surface of the resistance adjustment layer is subjected to a cured film treatment with a curing agent.

  The cured film treatment is performed, for example, by immersing the resistance adjustment layer in a treatment solution containing an isocyanate-containing compound, but may be performed by forming a cured treatment film layer on the surface of the resistance adjustment layer. In addition, a gap can be created between the photosensitive member and the charging roller by sticking an adhesive sheet having one side made of polyester or polyethylene terephthalate, for example, to each end of the charging roller unit. A contact proximity method can be realized. Then, by applying a DC voltage or a voltage obtained by superimposing an AC voltage and a DC voltage to the charging roller mandrel, the surface of the photoreceptor can be charged by causing a proximity discharge. This makes it possible to significantly suppress the amount of ozone generated during charging as compared to a so-called corotron or scorotron using a discharge wire.

In the developing device 4, a developing sleeve 4 a provided with a magnetic field generating unit is disposed at a position facing the photoconductor 1. Below the developing sleeve 4a, there are provided two screws 4b for mixing toner introduced from a toner bottle (not shown) with the developer and pumping it up to the developing sleeve 4a while stirring. The developer composed of toner and magnetic carrier pumped up by the developing sleeve 4a is regulated to a predetermined developer layer thickness by the doctor blade 4c and is carried on the developing sleeve 4a. The developing sleeve 4a carries and conveys the developer while moving in the same direction at a position facing the photoconductor 1, and supplies toner to the latent image surface of the photoconductor 1.
In FIG. 1, the configuration of the two-component developing type developing device 4 is shown, but the present invention is not limited to this, and a one-component developing type developing device can also be applied.

  The lubricant application device 3 includes a solid lubricant 3 b housed in a fixed case, and a brush roller 3 a that scrapes the lubricant in contact with the solid lubricant 3 b and applies it to the photoreceptor 1. The solid lubricant 3b is formed in a rectangular parallelepiped shape and is urged toward the brush roller 3a by the pressing member 3c. The pressurizing member 3c is preferably a spring such as a leaf spring or a compression spring, and a compression spring can be preferably used as shown in the drawing. The solid lubricant 3b is scraped off and consumed by the brush roller 3a, and the thickness of the solid lubricant 3b decreases with time. However, since the solid lubricant 3b is pressurized by the pressure member 3c, it is always in contact with the brush roller 3a. The brush roller 3 a applies the lubricant scraped off while rotating to the surface of the photoreceptor 1.

A cleaning device 8 is installed downstream of the lubricant application device 3.
The cleaning device 8 includes a cleaning blade 8a, a support member 8b, a toner recovery coil 8c, and a blade pressure spring 8d. The cleaning blade 8a is formed by forming a rubber such as urethane rubber or silicone rubber into a plate shape, and the edge of the cleaning blade 8a is in contact with the surface of the photoconductor 1 to remove the toner on the photoconductor 1 remaining after transfer. To do. The cleaning blade 8 a is attached to and supported by a support member 8 b made of metal, plastic, ceramic, or the like, and is installed at a predetermined angle with respect to the surface of the photoreceptor 1. Further, the blade pressing spring 8d is brought into contact with the surface of the photosensitive member 1 with a predetermined contact pressure and a biting amount.
The cleaning blade 8 a removes the toner on the photoreceptor 1 and also serves as an application blade that extends the lubricant applied on the photoreceptor by the lubricant application device 3 into a thin film.

FIG. 3 is a view showing another embodiment of the lubricant application device.
The lubricant application device 3 includes a solid lubricant 3 b housed in a fixed case, and a brush roller 3 a that scrapes the lubricant in contact with the solid lubricant 3 b and applies it to the photoreceptor 1. The solid lubricant 3b is formed in a rectangular parallelepiped shape and is urged toward the brush roller 3a by the pressure member 3c. The pressurizing member 3c is preferably a spring such as a leaf spring or a compression spring, and a compression spring can be preferably used as shown in the drawing. The solid lubricant 3b is scraped off and consumed by the brush roller 3a, and the thickness of the solid lubricant 3b decreases with time. However, since the solid lubricant 3b is pressurized by the pressure member 3c, it is always in contact with the brush roller 3a. The brush roller 3 a applies the lubricant scraped off while rotating to the surface of the photoreceptor 1. Further, a leveling blade 3d, a support member 3e, and a pressure spring 3f are installed on the downstream side of the brush roller 3a. The granular lubricant applied on the photoconductor by the brush roller 3a is formed into a uniform film on the photoconductor by the leveling blade 3d.

A cleaning device 8 described below is installed upstream of the lubricant application device 3.
Since the lubricant is applied after the transfer residual toner on the photosensitive member 1 is removed by the cleaning device, the lubricant can be uniformly applied on the photosensitive member regardless of toner input.
The cleaning device 8 includes a cleaning blade 8a, a support member 8b, a toner recovery coil 8c, and a blade pressure spring 8d. The cleaning blade 8a is formed by forming a rubber such as urethane rubber or silicone rubber into a plate shape, and the edge of the cleaning blade 8a is in contact with the surface of the photoconductor 1 to remove the toner on the photoconductor 1 remaining after transfer. To do. The cleaning blade 8 a is attached to and supported by a support member 8 b made of metal, plastic, ceramic, or the like, and is installed at a predetermined angle with respect to the surface of the photoreceptor 1. Further, the blade pressing spring 8d is brought into contact with the surface of the photosensitive member 1 with a predetermined contact pressure and a biting amount.

The lubricant application device 3 will be described in more detail.
As the solid lubricant 3b, a fatty acid metal salt (metal soap), a fluorine resin, or the like can be used, and a fatty acid metal salt is particularly preferable. Examples of the fatty acid metal salt include fatty acid metal salts of linear hydrocarbons such as myristic acid, palmitic acid, stearic acid, and oleic acid. Examples of the metal include lithium, magnesium, calcium, strontium, zinc, cadmium, Examples include aluminum, cerium, titanium, and iron. Among these, zinc stearate, magnesium stearate, aluminum stearate, iron stearate and the like are preferable, and zinc stearate is particularly preferable.
Further, the following configuration is also suitable as the lubricant.

What contains hydrophobic organic compound (A) and amphiphilic organic compound (B) as an essential component.
Examples of the hydrophobic organic compound (A) include aliphatic saturated hydrocarbons, aliphatic unsaturated hydrocarbons, alicyclic saturated hydrocarbons, alicyclic unsaturated hydrocarbons and aromatic hydrocarbons as described above. In addition to the classified hydrocarbons, polytetrafluoroethylene (PTFE), polyperfluoroalkyl ether (PFA), perfluoroethylene-perfluoropropylene copolymer (FEP), polyvinylidene fluoride (PVdF), ethylene -Examples include, but are not limited to, fluorine resins such as tetrafluoroethylene copolymer (ETFE) and fluorine waxes, silicone resins such as polymethyl silicone and polymethyl phenyl silicone, and silicone waxes. .

On the other hand, examples of the amphiphilic organic compound (B) include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant as described above.
Examples of anionic surfactants include alkylbenzene sulfonate, α-olefin sulfonate, alkane sulfonate, alkyl sulfate, alkyl polyoxyethylene sulfate, alkyl phosphate, long chain fatty acid salt, α -Anion (anion) at the end of the hydrophobic site, such as sulfo fatty acid ester salt and alkyl ether sulfate, and alkali metal ions such as sodium and potassium, and alkaline earth metal ions such as magnesium and calcium , Compounds in which metal ions such as aluminum and zinc, ammonium ions, and the like are bonded.
Examples of cationic surfactants include a cation (cation) at the end of a hydrophobic site, such as alkyltrimethylammonium salt, dialkylmethylammonium salt, alkyldimethylbenzylammonium salt, etc., and chlorine, fluorine , Bromine and the like, and compounds in which phosphate ions, nitrate ions, sulfate ions, thiosulfate ions, carbonate ions, hydroxide ions, and the like are bonded.

Examples of amphoteric surfactants include dimethylalkylamine oxide, N-alkylbetaines, imidazoline derivatives, alkyl amino acids and the like.
Examples of nonionic surfactants include alcohol compounds such as long-chain alkyl alcohols, alkyl polyoxyethylene ethers, polyoxyethylene alkyl phenyl ethers, fatty acid diethanolamides, alkyl polyglucooxides, polyoxyethylene sorbitan alkyl esters, ethers Examples thereof include compounds and amide compounds. In addition, long-chain alkyl carboxylic acids such as lauric acid, palmitic acid, stearic acid, behenic acid, lignoceric acid, serotic acid, montanic acid, and melicic acid, and polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, erythritol, and hexitol And ester compounds with these partial anhydrides are also preferred.

More specific examples of ester compounds include glyceryl monostearate, glyceryl distearate, glyceryl monopartic acid, glyceryl dilaurate, glyceryl trilaurate, glyceryl dipartimate, glyceryl tripartinate, glyceryl dimyristate, trimyristate Glyceryl palmitate, glyceryl stearate, glyceryl monoarachidate, glyceryl diarachidate, glyceryl monobehenate, glyceryl stearate, glyceryl stearate, glyceryl monomontanate, and glyceryl monomelinate Sorbitan monostearate, sorbitan tristearate, sorbitan monopartitic acid, sorbitan dipartitic acid, Sorbitan lipartinate, sorbitan dimyristate, sorbitan trimyristate, sorbitan palmitate stearate, sorbitan monoarachidate, sorbitan diarachidate, sorbitan monobehenate, sorbitan behenate stearate, sorbitan stearate sorbitan monomontanate, monomelicine Examples of the alkyl carboxylic acid sorbitan such as sorbitan acid and the substitution thereof are not limited thereto.
These amphiphilic organic compounds may be used in combination.

As a method for molding the image carrier lubricant of the present invention into a fixed shape, for example, a prismatic shape or a cylindrical shape, a method known as a solid material molding method can be used.
Examples include, but are not limited to, melt molding, powder molding, hot press molding, cold isostatic pressing (CIP), hot isostatic pressing (HIP), etc. Absent.
Taking a melt molding method as an example, a specific molding method of the image carrier lubricant will be described.
A predetermined amount of heat-melted glyceryl alkylcarboxylate is poured into a mold having a predetermined shape that has been heated to a temperature equal to or higher than the melting temperature of the image carrier lubricant, and if necessary, maintained at a temperature equal to or higher than the melting point for a certain period of time and then released. A molded body can be obtained by cooling by cooling or slow cooling. In order to remove the internal distortion of the molded product, the cooling proceeds to a temperature lower than the phase transition temperature of the image carrier lubricant component in the course of cooling, and then slowly restarts again to a temperature higher than the phase transition temperature. You may heat.
After cooling to a temperature close to room temperature, the molded body is removed from the mold to obtain a molded body of the image carrier lubricant.
Thereafter, the shape of the image carrier lubricant may be further adjusted by cutting or the like.
As the above-mentioned formwork, metal formwork such as steel, stainless steel, and aluminum is preferable because of good thermal conductivity and good dimensional accuracy. The inner wall surface of the mold is preferably coated with a release agent such as a fluororesin or a silicone resin in order to improve the releasability.

The solid lubricant 3b obtained by molding the fatty acid metal salt as described above into a rectangular parallelepiped shape is fixed to a lubricant holding member (not shown). In the case that accommodates the solid lubricant 3b, a plurality of pressure members 3c that are urged toward the brush roller 3a are provided side by side in the longitudinal direction.
The pressure applied to the brush roller 3a by the solid lubricant 3b is set to be in the range of 200 to 1000 mN as the total pressure of the pressure members 3c. When the total pressure is less than 200 mN, the solid lubricant 3b is not sufficiently scraped off by the brush roller 3a, and the amount of lubricant applied to the surface of the photoreceptor 1 is insufficient. As a result, abrasion of the cleaning blade 8a and the surface of the photosensitive member 1 is promoted, and cleaning defects such as transfer residual toner are likely to occur. When the total pressure exceeds 1000 mN, the amount of lubricant applied to the surface of the photoreceptor 1 becomes excessive. This is because not only the solid lubricant 3b is consumed quickly but also the surface of the photoreceptor 1 is affected by humidity due to excessive application of a lubricant composed of a hygroscopic fatty acid metal salt and the like. This causes a problem that an image flows and image blur occurs. Therefore, the solid lubricant 3b is preferably pressed against the brush roller 3a at a total pressure of 200 to 1000 mN.

In the brush roller, a sheet made of fiber is bonded to a cored bar made of stainless steel or iron. The outer diameter of the metal core is φ6, and the outer diameter of the brush roller is φ14.
As a specific material of the brush fiber, one or more kinds selected from generally known materials can be selected and used. Specifically, polyolefin resins (for example, polyethylene, polypropylene); polyvinyl and polyvinylidene resins (for example, 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, mela Down resins, benzoguanamine resins, urea resins, polyamide resins); Among such, it may be a resin having flexibility.
Also, 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. are used in combination. Also good.

  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 polyvinyl ketone; vinyl chloride-vinyl acetate copolymer; silicone resin composed of an organosiloxane bond or a modified product thereof (for example, alkyd) Modified products with oils, polyester resins, epoxy resins, polyurethane, etc.); Fluorine resins such as perfluoroalkyl ether, polyfluorovinyl, polyfluorovinylidene, polychlorotrifluoroethylene; polyamides; polyesters; polyurethanes; polycarbonates; urea-formaldehyde resins An amino resin such as an epoxy resin or a composite resin thereof.

FIG. 4 is a schematic diagram for explaining the configuration of the brush. The figure (a) is a figure which shows the case where the ratio of the fiber with a long bristle is made larger than the fiber with the short bristle, and the figure (b) shows the case where both ratios are made equal.
In the same figure, the code | symbol 3a2 shows the sheet | seat which has a fiber with a long bristle, and 3a3 shows the sheet | seat which has a fiber with short bristle.
The brush roller is composed of two types of fibers having different bristle lengths.
The longer fiber of the brush roller has a bristle length of 5 mm and contacts both the solid lubricant and the image carrier, whereas the shorter fiber of the brush roller has a bristle length of 3 mm. The position of the shaft of the brush with respect to the photosensitive member and the contact pressure of the solid lubricant with respect to the brush are adjusted so that the shorter fiber does not contact with the solid lubricant but only with the image carrier.
The longer fiber is 0.5 to 3 denier, the density of the brush fiber is 100,000 to 600,000 / inch ² , the shorter fiber is thicker, 6 to 20 denier, and the density of the brush fiber is 1. 10,000 to 50,000 pieces / inch ² .
As shown in FIGS. 2A and 2B, the brush roller is formed by arranging two sheets 3a2 and 3a3 having different fiber lengths and sticking them to the cored bar 3a1 in a spiral shape, thereby making the brush rollers having different lengths of bristles. Is made. The ratio of the number of the long fibers 3a2 and the short fibers 3a3 can be adjusted by the ratio of the sheet width.

  As a result of detailed observation of the existence state of the lubricant on the photosensitive member by the present inventors, the lubricant is present in a powdery state immediately after being scraped off with a brush. It was found that when it passed, it was stretched into a film shape and exhibited lubricity. In addition, it has been clarified that the lubricant present in the form of a film does not transfer to the charging member, but the powdery lubricant transfers to the charging member by an electric field and causes contamination. It has been found that when the brush fibers are thick, the granular lump of the lubricant becomes large, and when the brush fibers are thin, the granular lump is small and decreases in number. If the brush fiber is too thick, when the solid lubricant is scraped off with the brush, a granular lump of the lubricant increases and adheres to the surface of the photoreceptor in a granular form. The lump of granular lubricant rubs through the blade, and there is a granular lubricant on the order of several microns on the surface of the photoreceptor. In the present invention, by setting the thickness of the brush fiber in contact with the solid lubricant to 0.5 to 3 denier, the lubricant that becomes granular on the surface of the photoconductor after the lubricant is applied is reduced, and contamination of the charging roller is suppressed. ing.

One shorter fiber has a thicker brush fiber than the longer fiber, a brush fiber thickness of 6 to 20 denier, and a brush fiber density of 10,000 to 50,000 fibers / inch ² . Residual toner on the photoconductor is scattered, and at the same time, the surface of the photoconductor is appropriately roughened and polished so that the lubricant can be easily applied. In a photoconductor having a cross-linked curable resin as a surface layer as in this embodiment, since the hardness is high, the film thickness of the photoconductor is small even if the fiber is thick, and conversely, the thicker fiber makes the photoconductor surface rougher. As a result, irregularities are formed and a uniform film of the lubricant is easily formed. As a method for obtaining the same effect, there is a method using a fiber having a larger elastic modulus. In this case, it is not necessary to increase the thickness of the fiber so much. By combining the fiber thickness and the elastic modulus, more appropriate characteristics can be obtained.

A cleaning blade 8a, a support member 8b, and a pressure spring 8c are installed as a cleaning device downstream of the application brush roller 3a. The toner remaining on the photoconductor is removed by the cleaning blade 8a, and the lubricant applied on the photoconductor by the application brush roller 3a is uniformly extended to form a thin layer. By installing a brush composed of two fibers having different lengths and thicknesses, it is possible to remove toner on the photoreceptor, polish the surface of the photoreceptor, and apply a lubricant with a single brush.
As shown in FIG. 2, the rotation direction of the brush roller 3a is preferably forward with respect to the moving direction of the photosensitive member 1. When the rotation direction of the brush roller 3a is opposite to the moving direction of the photosensitive member 1, the lubricant powder adhering to the brush fibers of the brush roller 3a is repelled by the impact abutting on the surface of the photosensitive member 1, Uniform and efficient application is not possible. Therefore, the rotation direction of the brush roller 3a is preferably the forward direction with respect to the moving direction of the photosensitive member 1.

FIG. 5 is a schematic view showing another embodiment of the brush roller. The figure (a) is a figure which shows the example which changed the angle of flocking, and the figure (b) is a partially abbreviated enlarged view which shows the example which made flocking into loop shape.
As shown in FIG. 5A, only the thin fibers 3a2 having long hairs may be implanted obliquely with respect to the axial direction of the brush. By falling down, the scraping of the solid lubricant becomes softer, and uniform application without a granular lump of lubricant can be performed on the photoreceptor. When configured as shown in FIG. 4, long and short bristle legs are alternately arranged with a narrow interval in one cross section, but when rotated, all the positions in the axial direction are placed on the lubricant and the photoconductor. Since both long and short hairs come into contact with each other, they are shown schematically as shown in the figure.
In still another embodiment, as shown in FIG. 4B, only the short-legged fibers 3a3 are formed in a loop shape. By forming the loop shape, the rigidity is increased and the force to wear the photoconductor as a brush is strong, and the surface of the photoconductor can be appropriately worn to keep the surface rough. In the figure, for the sake of easy understanding, a part of the brush with the longer bristle is omitted.

  By providing the image forming apparatus with the lubricant application device 3 having the above-described configuration, an appropriate amount of lubricant can be uniformly applied to the surface of the photoreceptor 1, and a uniform thin film of lubricant can be formed. . As a result, the cleaning blade 8a and the surface of the photoreceptor 1 can be prevented from being worn, and the charging roller can be prevented from being contaminated by the lubricant, so that a stable image can be obtained over a long period of time.

  The above-described lubricant application device 3 can be used not only for applying a lubricant to the surface of the photoreceptor 1 but also as a device for applying a lubricant to the surface of the intermediate transfer belt 56 in FIG. In this case, the lubricant applying device 3 may be provided adjacent to the intermediate transfer belt cleaning device 57 or may be included in the intermediate transfer belt cleaning device 57. The lubricant application device 3 is provided upstream of the intermediate transfer belt cleaning device 57 in the moving direction of the intermediate transfer belt 56, the lubricant is applied to the surface of the intermediate transfer belt 56, and the cleaning is provided in the intermediate transfer belt cleaning device 57. Stretching with a blade forms a thin layer of lubricant. Thereby, it is possible to satisfactorily clean deposits such as toner remaining on the surface of the intermediate transfer belt 56 without being subjected to secondary transfer at the nip portion with the secondary transfer roller 61.

  Further, the lubricant applying device 3 is integrally supported including the photosensitive member 1 and any means selected from the charging device 2, the developing device 4, and the cleaning device 8, and is detachably attached to the image forming apparatus main body. The process cartridge can be formed. The installation position of the lubricant application device 3 in the process cartridge is upstream of the cleaning device 8 in the moving direction of the photosensitive member 1 as described above when integrated with the cleaning device 8. With this process cartridge, the cleaning performance of the surface of the photoreceptor 1 can be maintained for a long period of time, and a process cartridge that does not cause deterioration in image quality can be obtained.

Here, the photoreceptor used in the present invention will be described in detail.
In the photoreceptor used in the image forming apparatus of the present invention, a photosensitive layer is provided on a conductive support. The photosensitive layer is composed of a single layer type in which a charge generation material and a charge transport material are mixed, a forward layer type in which a charge transport layer is provided on the charge generation layer, or a charge generation layer provided on the charge transport layer. There is a reverse layer type. In addition, a protective layer can be provided on the photosensitive layer in order to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property, and the like of the photoreceptor. An undercoat layer may be provided between the photosensitive layer and the conductive support. In addition, an appropriate amount of a plasticizer, an antioxidant, a leveling agent and the like can be added to each layer as necessary.

Examples of the conductive support for the photoreceptor include those having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, oxidation Metal oxide such as indium by vapor deposition or sputtering, film or cylindrical plastic, paper coated, or plates such as aluminum, aluminum alloy, nickel, stainless steel, etc., and methods such as extrusion and drawing After forming the tube into a drum shape, it is possible to use a tube that has been surface-treated by cutting, superfinishing, polishing, or the like. A drum-shaped support having a diameter of 20 to 150 mm, preferably 24 to 100 mm, and more preferably 28 to 70 mm can be used. If the diameter of the drum-shaped support is 20 mm or less, it is physically difficult to arrange the charging, exposure, development, transfer, and cleaning steps around the drum. If the diameter of the drum-shaped support is 150 mm or more, image formation is performed. The apparatus becomes undesirably large. In particular, when the image forming apparatus is a tandem type, it is necessary to mount a plurality of photoconductors, and therefore the diameter is preferably 70 mm or less, and preferably 60 mm or less. Also, known endless nickel belts and endless stainless steel belts can be used as the conductive support.

  As the undercoat layer of the photoreceptor used in the image forming apparatus of the present invention, a resin, or a material mainly composed of a white pigment and a resin, a metal oxide film obtained by chemically or electrochemically oxidizing the surface of a conductive substrate, etc. However, those containing a white pigment and a resin as main components are preferable. Examples of the white pigment include metal oxides such as titanium oxide, aluminum oxide, zirconium oxide, and zinc oxide. Among them, it is most preferable to contain titanium oxide that is excellent in preventing charge injection from the conductive substrate. As the resin used for the undercoat layer, thermoplastic resins such as polyamide, polyvinyl alcohol, casein, and methyl cellulose, thermosetting resins such as acrylic, phenol, melamine, alkyd, unsaturated polyester, and epoxy, one or various kinds of these Mixtures can be exemplified.

  Examples of the charge generating material for the photoreceptor used in the image forming apparatus of the present invention include azo pigments such as monoazo pigments, bisazo pigments, trisazo pigments, tetrakisazo pigments, triarylmethane dyes, thiazine dyes, Oxazine dyes, xanthene dyes, cyanine dyes, styryl dyes, pyrylium dyes, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, bisbenzimidazole pigments, indanthrone pigments, squarylium Organic pigments and dyes such as pigments, phthalocyanine pigments, inorganic materials such as selenium, selenium-arsenic, selenium-tellurium, cadmium sulfide, zinc oxide, titanium oxide, amorphous silicon, etc. can be used, and charge generating substances Can be used alone or in combination. The undercoat layer may be a single layer or a plurality of layers.

  Examples of the charge transport material for the photoreceptor used in the image forming apparatus of the present invention include anthracene derivatives, pyrene derivatives, carbazole derivatives, tetrazole derivatives, metallocene derivatives, phenothiazine derivatives, pyrazoline compounds, hydrazone compounds, styryl compounds, styryl hydrazone compounds, Enamine compounds, butadiene compounds, distyryl compounds, oxazole compounds, oxadiazole compounds, thiazole compounds, imidazole compounds, triphenylamine derivatives, phenylenediamine derivatives, aminostilbene derivatives, triphenylmethane derivatives, etc. can do.

  The binder resin used for forming the photosensitive layer of the charge generation layer and the charge transport layer is an electrically insulating and known per se thermoplastic resin, thermosetting resin, photocurable resin, and light. Conductive resins can be used, and suitable binder resins include, for example, polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymers. , Ethylene-vinyl acetate copolymer, polyvinyl butyral, polyvinyl acetal, polyester, phenoxy resin, (meth) acrylic resin, polystyrene, polycarbonate, polyarylate, polysulfone, polyethersulfone, ABS resin and other thermoplastic resins, phenol Resin, epoxy resin, urethane resin, melamine resin, isocyanate resin, alkyd tree Examples thereof include thermosetting resins such as silicone resins and thermosetting acrylic resins, and one kind of binder resins such as photoconductive resins such as polyvinyl carbazole, polyvinyl anthracene, and polyvinyl pyrene, and mixtures of various kinds of binder resins. However, the present invention is not particularly limited to these.

As antioxidant, the following are used, for example.
Monophenol compounds 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di- t-butyl-4-hydroxyphenyl) propionate, 3-t-butyl-4-hydroxynisol and the like.
Bisphenol compounds 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2′-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4 ′ -Thiobis- (3-methyl-6-t-butylphenol), 4,4'-butylidenebis- (3-methyl-6-t-butylphenol) and the like.

-High molecular phenol compound 1,1,3-tris- (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3, 5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3 '-Bis (4'-hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, tocophenols, and the like.
Paraphenylenediamines N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N′-di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.

Hydroquinones 2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- ( 2-octadecenyl) -5-methylhydroquinone and the like.
Organic sulfur compounds Dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like.
Organic phosphorus compounds Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine and the like.

As the plasticizer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is about 0 to 30 parts by weight with respect to 100 parts by weight of the binder resin. Is appropriate.
A leveling agent may be added to the charge transport layer. As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain are used, and the amount used is 100 parts by weight of the binder resin. 0 to 1 part by weight is suitable.

  As described above, the surface layer is provided to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property, etc. of the photoreceptor. Examples of the surface layer include a polymer having a mechanical strength higher than that of the photosensitive layer and a polymer in which an inorganic filler is dispersed. The polymer used for the surface layer may be either a thermoplastic polymer or a thermosetting polymer, but the thermosetting polymer has a high mechanical strength and does not wear due to friction with the cleaning blade. It is very preferable because of its extremely high ability to suppress. If the surface layer has a thin film thickness, there is no problem even if it does not have the charge transport capability. However, 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 use the above-mentioned charge transporting substance in the surface layer, or to use a polymer having charge transporting ability for the protective layer.

  When the surface layer is provided, the mechanical strength of the photosensitive layer and the surface layer is generally greatly different, and therefore the protective layer is worn away due to friction with the cleaning blade. It is important that the surface layer has a sufficient film thickness, and is 0.01 to 12 μm, preferably 1 to 10 μm, more preferably 2 to 8 μm. If the film thickness of the surface layer is 0.1 μm or less, it is not preferable because it is too thin and easily disappears due to friction with the cleaning blade, and wear of the photosensitive layer proceeds from the disappeared portion. When the film thickness of the surface layer is 12 μm or more, the sensitivity is lowered, the potential after exposure is increased, and the residual potential is easily increased. In particular, when a polymer having charge transport capability is used, the cost of the polymer having charge transport capability is high. This is not preferable.

  The polymer used for the surface layer is preferably a material that is transparent to the writing light during image formation and has excellent insulation, mechanical strength, and adhesiveness. ABS resin, ACS resin, olefin-vinyl monomer copolymer , Chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethyl Examples include resins such as bentene, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polyvinylidene chloride, and epoxy resin. . These polymers may be thermoplastic polymers, but in order to increase the mechanical strength of the polymers, they are crosslinked with a crosslinking agent having a polyfunctional acryloyl group, carboxyl group, hydroxyl group, amino group, etc. By using a curable polymer, the mechanical strength of the surface layer is increased, and wear due to friction with the cleaning blade can be greatly reduced.

As described above, it is preferable that the surface layer has a charge transport capability. In order to provide the surface layer with a charge transport capability, a polymer used for the surface layer and the above-described charge transport material are mixed. A method of using a polymer having a charge transporting capability for the surface layer is conceivable, and the latter method is preferable because it can obtain a photoconductor with high sensitivity and little increase in potential after exposure and little increase in residual potential.
Examples of the polymer having a charge transport layer ability include a group having a charge transport ability in the polymer; chemical formula (1).
In the formula, Ar ₁ represents a substituted or unsubstituted arylene group. Ar ₂ and Ar ₃ represent a substituted or unsubstituted aryl group, and may be the same or different.
The group having the charge transporting ability is preferably added to a side chain of a polymer having high mechanical strength such as a polycarbonate resin or an acrylic resin, and the monomer can be easily produced, and the acrylic having excellent coatability and curability. It is preferable to use a resin.

  An acrylic resin having a charge transporting ability may form a surface layer having high mechanical strength, excellent transparency, and high charge transporting ability by polymerizing an unsaturated carboxylic acid having a group of chemical formula (1). The acrylic resin forms a crosslinked structure by mixing a polyfunctional unsaturated carboxylic acid, preferably a tri- or higher functional unsaturated carboxylic acid, with the unsaturated carboxylic acid having a monofunctional chemical formula (1) group. It becomes a thermosetting polymer, and the mechanical strength of the surface layer becomes extremely high. Although the group of the chemical formula (1) may be added to the polyfunctional unsaturated carboxylic acid, since the production cost of the monomer becomes high, the polyfunctional unsaturated carboxylic acid has a group of the chemical formula (1). Usually, it is preferable to use a photocurable polyfunctional monomer.

Examples of the monofunctional unsaturated carboxylic acid having a group represented by the chemical formula (1) include the chemical formula (2) and the chemical formula (3).
In both formulas, R ₁ represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a cyano group, a nitro group, Group, alkoxy group, —COOR ₇ (R ₇ is a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent or an aryl group which may have a substituent), halogen Carbonyl group or CONR ₈ R ₉ (R ₈ and R ₉ may have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent or a substituent. Represents a good aryl group, which may be the same or different from each other, and Ar ₁ and Ar ₂ represent a substituted or unsubstituted arylene group, which may be the same or different. Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group, and may be the same or different. X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group. Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, or an alkyleneoxycarbonyl divalent group. m and n represent an integer of 0 to 3.

The proportion of the polyfunctional unsaturated carboxylic acid is 5 to 75% by weight, preferably 10 to 70% by weight, more preferably 20 to 60% by weight, based on the entire surface layer. When the ratio of the polyfunctional unsaturated carboxylic acid is 5% by weight or less, the mechanical strength of the surface layer is insufficient, and when it is 75% or more, cracks are likely to occur when a strong force is applied to the surface layer, resulting in sensitivity deterioration. Is also not preferable because it is likely to occur.
When an acrylic resin is used for the surface layer, the surface layer is formed by applying the unsaturated carboxylic acid to the photoreceptor and then irradiating with an electron beam or actinic rays such as ultraviolet rays to cause radical polymerization. Can do. When performing radical polymerization with actinic rays, a solution obtained by dissolving a photopolymerization initiator in an unsaturated carboxylic acid is used. As the photopolymerization initiator, materials used for photocurable paints can be used.
In the surface layer, fine particles of metal or metal oxide can be dispersed in order to increase the mechanical strength of the surface layer. Examples of the metal oxide include titanium oxide, tin oxide, potassium titanate, TiO, TiN, zinc oxide, indium oxide, and antimony oxide. In addition, fluorine resins such as polytetrafluoroethylene, silicone resins, and those obtained by dispersing inorganic materials in these resins can be added for the purpose of improving wear resistance.

In the image forming apparatus of the present invention, the toner used in the developing device 4 has a volume average particle diameter of 3 to 6 μm, and the ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn). Is preferably in the range of 1.00 to 1.40.
By using a toner having a small particle diameter, the toner can be densely attached to the latent image. However, when the volume average particle size is smaller than the above range, in the case of a two-component developer, the toner is fused to the surface of the magnetic carrier during a long period of stirring in the developing device, and the charging ability of the magnetic carrier is lowered. When used as an agent, toner filming on the developing roller and toner fusion to a member such as a blade for thinning the toner are likely to occur. Conversely, when the volume average particle diameter of the toner is larger than the above range, it becomes difficult to obtain a high-resolution and high-quality image, and the toner in the developer is balanced. In many cases, the variation in the particle size of the particles increases.

By narrowing the particle size distribution, the toner charge amount distribution becomes uniform, a high-quality image with little background fogging can be obtained, and the transfer rate can be increased. However, it is not preferable that Dv / Dn exceeds 1.40 because the charge amount distribution becomes wide and the resolving power decreases.
The average particle size and particle size distribution of the toner can be measured using a Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). Specifically, a Coulter counter TA-II type was used, connected to an interface (manufactured by Nikka Giken Co., Ltd.) for outputting the number distribution and volume distribution, and a personal computer (PC9801: manufactured by NEC) and measured.

  In the toner as described above, the ratio of the wax added to the toner to improve the releasability or the inorganic fine particles to improve the fluidity is small in the particle size. As a result, it is higher than the conventional toner. These additives are the cause of the adhered substances generated on the photoreceptor 1. Therefore, by mounting the lubricant application device 3 of the present invention, a uniform thin film of lubricant can be formed over the entire surface of the photoreceptor 1 and the adhesion force of these adhered substances to the surface of the photoreceptor 1 can be reduced. it can. In addition, the frictional force acting between the surface of the photosensitive member 1 and the cleaning blade 8a of the cleaning device 8 can be reduced so that the cleaning can be performed satisfactorily.

FIG. 6 is a diagram schematically illustrating the shape of the toner in order to explain the shape factor.
The toner used in the developing device 4 preferably has a shape factor SF-1 in the range of 100 to 150 and a shape factor SF-2 in the range of 100 to 150.
Here, the shape factor SF-1 indicates the ratio of the roundness of the toner shape, and is represented by the following formula (1). A value obtained by dividing the square of the maximum length Lmax of the shape formed by projecting the toner onto a two-dimensional plane by the figure area A and multiplying by 100π / 4. This represents the ratio of the area of a circle whose diameter is Lmax to a perfect circle having an area A.
SF-1 = {(Lmax) ² / A} × (100π / 4) Expression (1)
When the value of SF-1 is 100, the shape of the toner becomes a true sphere, and becomes larger as the value of SF-1 increases.

The shape factor SF-2 indicates the ratio of unevenness in the shape of the toner, and is represented by the following formula (2). This is a value obtained by dividing the square of the perimeter Lper of the figure formed by projecting the toner on the two-dimensional plane by the figure area A and multiplying by 100 / 4π. This represents the ratio of the area of a circle having a circumference equal to the figure circumference Lper to the area of a perfect circle having area A.
SF-2 = {(Lper) ² / A} × (100 / 4π) (2)
When the value of SF-2 is 100, there is no unevenness on the toner surface, and as the value of SF-2 increases, the unevenness of the toner surface becomes more prominent.

When the shape of the toner is close to a sphere, the contact between the toner and the toner, or the contact between the toner and the photoreceptor 1 becomes close to a point contact, so that the adsorbing force between the toners becomes weak, and thus the fluidity becomes high. Also, the adsorption force between the photosensitive member 1 and the photosensitive member 1 is weakened, and the transfer rate is increased. On the other hand, since spherical toner tends to enter the gap between the cleaning blade 8a and the photoreceptor 1, the toner shape factor SF-1 or SF-2 is preferably large to some extent. Further, when SF-1 and SF-2 are increased, toner is scattered on the image and the image quality is lowered. For this reason, it is preferable that SF-1 and SF-2 do not exceed 150.
Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.), and introducing it into an image analyzer (LUSEX 3: manufactured by Nireco) for analysis. And calculated.

  The toner suitably used in the image forming apparatus of the present invention is, for example, a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent are dispersed in an organic solvent. Is a toner obtained by performing a crosslinking and / or elongation reaction (at least one of crosslinking and elongation) in an aqueous solvent. Hereinafter, description will be given with examples of toner constituent materials and manufacturing methods.

-Modified polyester The toner according to the present invention contains a modified polyester (i) as a binder resin. The modified polyester (i) refers to a state in which a bonding group other than an ester bond is present in the polyester resin, or resin components having different configurations are bonded to the polyester resin by a covalent bond, an ionic bond, or the like. Specifically, the polyester terminal is modified by introducing a functional group such as a carboxylic acid group or an isocyanate group that reacts with a hydroxyl group into the polyester terminal and further reacting with an active hydrogen-containing compound.

  Examples of the modified polyester (i) include urea-modified polyester obtained by a reaction between a polyester prepolymer (A) having an isocyanate group and amines (B). As the polyester prepolymer (A) having an isocyanate group, a polyester having a polycondensate of a polyhydric alcohol (PO) and a polyvalent carboxylic acid (PC) and having an active hydrogen group is further added to a polyvalent isocyanate compound (PIC). And those reacted with. Examples of the active hydrogen group possessed by the polyester include hydroxyl groups (alcoholic hydroxyl groups and phenolic hydroxyl groups), amino groups, carboxyl groups, mercapto groups, and the like. Among these, alcoholic hydroxyl groups are preferred.

The urea-modified polyester is produced as follows.
Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable. Examples of the dihydric alcohol (DIO) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide bisphenol (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. The trihydric or higher polyhydric alcohol (TO) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

  Examples of the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) with a small amount of (TC) Mixtures are preferred. Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polyvalent carboxylic acid (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). In addition, as polyhydric carboxylic acid (PC), you may make it react with polyhydric alcohol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.).

  The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

  Examples of the polyvalent isocyanate compound (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.) ); Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanates; phenol derivatives, oximes, polyisocyanates; Those blocked with caprolactam or the like; and combinations of two or more of these.

  The ratio of the polyvalent isocyanate compound (PIC) is usually 5/1 to 1/1, preferably as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1, when a urea-modified polyester is used, the urea content in the ester is lowered and hot offset resistance is deteriorated.

The content of the polyvalent isocyanate compound (PIC) component in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40 wt%, preferably 1 to 30 wt%, more preferably 2 to 20 wt%. . If it is less than 0.5 wt%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40 wt%, the low-temperature fixability deteriorates.
The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

  Next, as amines (B) to be reacted with the polyester prepolymer (A), a divalent amine compound (B1), a trivalent or higher polyvalent amine compound (B2), an amino alcohol (B3), an amino mercaptan (B4) ), Amino acid (B5), and amino acid block of B1 to B5 (B6).

  Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexyl). Methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like. Examples of the trivalent or higher polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of the compound (B6) obtained by blocking the amino group of B1 to B5 include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

The ratio of amines (B) is equivalent to the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). Is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] is more than 2 or less than 1/2, the molecular weight of the urea-modified polyester is lowered, and the hot offset resistance is deteriorated.
The urea-modified polyester may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

The modified polyester (i) used above is produced by a one-shot method or a prepolymer method. The weight average molecular weight of the modified polyester (i) is usually 10,000 or more, preferably 20,000 to 10,000,000, more preferably 30,000 to 1,000,000. The peak molecular weight at this time is preferably 1000 to 10,000, and if it is less than 1000, the elongation reaction hardly occurs and the elasticity of the toner is small, and as a result, the hot offset resistance deteriorates. On the other hand, if it exceeds 10,000, the problem in production becomes high in the case where the fixing property is lowered, the particles are formed or pulverized. The number average molecular weight of the modified polyester (i) is not particularly limited when the unmodified polyester (ii) described later is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. (I) When used alone, the number average molecular weight is usually 20000 or less, preferably 1000 to 10000, and more preferably 2000 to 8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color apparatus are deteriorated.
In the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B) to obtain the modified polyester (i), a reaction terminator is used as necessary to adjust the molecular weight of the resulting urea-modified polyester. be able to. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).
In addition, the molecular weight of the produced | generated polymer can be measured using THF as a solvent using gel permeation chromatography (GPC).

Unmodified polyester In the present toner, not only the modified polyester (i) is used alone, but also the unmodified polyester (ii) can be contained as a binder resin component together with the (i). By using (ii) in combination, the low-temperature fixability and the gloss when used in a full-color device are improved, which is preferable to the single use. Examples of (ii) include polycondensates of a polyhydric alcohol (PO) and a polyvalent carboxylic acid (PC), which are the same as the polyester component (i), and preferred ones are also the same as (i). . Further, (ii) is not limited to unmodified polyester, but may be modified with a chemical bond other than a urea bond, for example, may be modified with a urethane bond. It is preferable that (i) and (ii) are at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Accordingly, the polyester component (i) and (ii) preferably have similar compositions. In the case of containing (ii), the weight ratio of (i) to (ii) is usually 5/95 to 80/20, preferably 5/95 to 30/70, more preferably 5/95 to 25/75, Particularly preferred is 7/93 to 20/80. If the weight ratio of (i) is less than 5%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The peak molecular weight of (ii) is 1000-10000 normally, Preferably it is 2000-8000, More preferably, it is 2000-5000. If it is less than 1000, heat-resistant storage stability will deteriorate, and if it exceeds 10,000, low-temperature fixability will deteriorate. The hydroxyl value of (ii) is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If it is less than 5, it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. As for the acid value of (ii), 1-5 are preferable, More preferably, it is 2-4. Since a high acid value wax is used as the wax, the low acid value binder leads to electrification and high volume resistance, so that it is easy to match the toner used for the two-component developer.

The glass transition point (Tg) of the binder resin is usually 35 to 70 ° C, preferably 55 to 65 ° C. If the temperature is lower than 35 ° C., the heat-resistant storage stability of the toner deteriorates, and if it exceeds 70 ° C., the low-temperature fixability becomes insufficient. Since urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the present toner tends to have good heat-resistant storage stability even when the glass transition point is low, as compared with known polyester-based toners.
The glass transition point (Tg) can be measured with a differential scanning calorimeter (DSC).

-Colorant As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow oxidation Iron, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Faisa Red, Parachlor Ortho Nitroaniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carnmin BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Tolujing Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake , Thioindigo red B, thioindigo maroon, oil red, quinacridone red, pyrazo Red, polyazo red, chrome vermillion, benzidine orange, perinone orange, oil orange, cobalt blue, cerulean blue, alkali blue rake, peacock blue rake, Victoria blue rake, metal free phthalocyanine blue, phthalocyanine blue, fast sky blue, indance Ren Blue (RS, BC), Indigo, Ultramarine Blue, Bitumen, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chrome Oxide, Pyridian, Emerald Green , Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green A rk, phthalocyanine green, anthraquinone green, titanium oxide, zinc white, lithopone and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the toner.

  The colorant can also be used as a master batch combined with a resin. As a binder resin to be kneaded together with the production of a master batch or a master batch, a polymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyl toluene or the like, or a copolymer of these and a vinyl compound, Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax and the like can be mentioned, and these can be used alone or in combination.

Charge control agents Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (Including fluorine-modified quaternary ammonium salt), alkylamide, phosphorus alone or compound, tungsten alone or compound, fluorine-based activator, salicylic acid metal salt, metal salt of salicylic acid derivative, and the like. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.

  The amount of the charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the flowability of the developer is lowered, and the image density is lowered. Invite.

Release agent As the release agent, a low melting point wax having a melting point of 50 to 120 ° C. works more effectively as a release agent in the dispersion with the binder resin between the fixing roller and the toner interface, As a result, it is effective against high temperature offset without applying a release agent such as oil to the fixing roller. Examples of such a wax component include the following. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, and rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, and petrolatum. And petroleum wax. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .
The charge control agent and the release agent can be melt-kneaded together with the master batch and the binder resin, and of course, they may be added when dissolved and dispersed in the organic solvent.

External additive Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × ¹⁰ -3 ~2μm, it is particularly preferably 5 × ¹⁰ -3 ~0.5μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The use ratio of the inorganic fine particles is preferably 0.01 to 5 wt% of the toner, and particularly preferably 0.01 to 2.0 wt%.
Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. In particular, when stirring and mixing are performed using particles having an average particle diameter of 5 × 10 ⁻² μm or less, the electrostatic force and van der Waals force with the toner are remarkably improved. Even when stirring and mixing inside the developing device is performed to obtain a good image quality that does not cause the release of the fluidity imparting agent from the toner and does not generate firefly, etc., and further reduces the residual toner. It is done.

  Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rise characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, this side effect is affected. It can be considered large. However, when the addition amount of the hydrophobic silica fine particles and the hydrophobic titanium oxide fine particles is in the range of 0.3 to 1.5 wt%, the charge rising characteristics are not greatly impaired, and the desired charge rising characteristics can be obtained. That is, stable image quality can be obtained even when copying is repeated.

Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.
Toner production method 1) A toner material liquid is prepared by dispersing a colorant, unmodified polyester, a polyester prepolymer having an isocyanate group, and a release agent in an organic solvent.
The organic solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal after toner base particle formation. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles.
The aqueous medium may be water alone or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included.
The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 2000 parts by weight, it is not economical.

Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added.
As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, fatty acid amide derivatives, polyhydric alcohols Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkyl carboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctane sulfonic acid diethanolamide, N-propyl-N- ( 2-hydroxyethyl) Perfluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Is mentioned.

  Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Daikin Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).

  Cationic surfactants include aliphatic primary, secondary or secondary amine acids having fluoroalkyl groups, aliphatic quaternary ammonium salts such as perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts, and benzas. Luconium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (manufactured by Asahi Glass), Florard FC-135 (manufactured by Sumitomo 3M), Unidyne DS-202 (manufactured by Daikin Industries) Megafac F-150, F-824 (manufactured by Dainippon Ink, Inc.), Xtop EF-132 (manufactured by Tochem Products), and Footgent F-300 (manufactured by Neos).

The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium. For this reason, it is preferable to add so that the coverage existing on the surface of the toner base particles is in the range of 10 to 90%. For example, polymethyl methacrylate fine particles 1 μm and 3 μm, polystyrene fine particles 0.5 μm and 2 μm, poly (styrene-acrylonitrile) fine particles 1 μm, trade names are PB-200H (manufactured by Kao Corporation), SGP (manufactured by Soken Co., Ltd.), Techno Examples include polymer SB (manufactured by Sekisui Chemical Co., Ltd.), SGP-3G (manufactured by Sokensha), and micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.).
In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

  As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, the high-speed shearing method is preferable in order to make the particle size of the dispersion 2 to 20 μm. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C.

3) At the same time as the preparation of the emulsion, the amines (B) are added to cause a reaction with the polyester prepolymer (A) having an isocyanate group.
This reaction involves molecular chain crosslinking and / or elongation. The reaction time is selected depending on the reactivity between the isocyanate group structure of the polyester prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.

4) After completion of the reaction, the organic solvent is removed from the emulsified dispersion (reactant), washed and dried to obtain toner base particles.
In order to remove the organic solvent, the temperature of the entire system is gradually raised in a laminar stirring state, and after giving strong stirring in a certain temperature range, the solvent base is removed to produce spindle-shaped toner base particles. . Further, when an acid such as calcium phosphate salt or an alkali-soluble material is used as the dispersion stabilizer, the calcium phosphate salt is dissolved from the toner base particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. Remove. It can also be removed by operations such as enzymatic degradation.

5) A charge control agent is injected into the toner base particles obtained above, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are externally added to obtain a toner.
The injection of the charge control agent and the external addition of the inorganic fine particles are performed by a known method using a mixer or the like.
Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained. Furthermore, by giving strong agitation in the process of removing the organic solvent, the shape between the true spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.

FIG. 7 is a diagram schematically showing the shape of the toner used in the present invention.
The toner used in the present invention has a substantially spherical shape, and can be represented by the following shape rule.
In the figure, when a substantially spherical toner is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), the toner used in the present invention has a major axis and a minor axis. (R2 / r1) (see FIG. 5B) is 0.5 to 1.0, and the ratio of thickness to short axis (r3 / r2) (see FIG. 3C) is 0.7. It is preferable that it exists in the range of -1.0. If the ratio of the major axis to the minor axis (r2 / r1) is less than 0.5, the dot reproducibility and transfer efficiency are inferior because of the separation from the true spherical shape, and high-quality image quality cannot be obtained. On the other hand, if the ratio of thickness to minor axis (r3 / r2) is less than 0.7, the shape is close to a flat shape, and a high transfer rate like a spherical toner cannot be obtained. In particular, when the ratio of the thickness to the minor axis (r3 / r2) is 1.0, the rotating body has a major axis as a rotation axis, and the fluidity of the toner can be improved.
Note that r1, r2, and r3 were measured with a scanning electron microscope (SEM) while changing the angle of field of view and taking pictures.

The toner produced as described above can also be used as a one-component magnetic toner that does not use a magnetic carrier or a non-magnetic toner.
When used in a two-component developer, it may be used by mixing with a magnetic carrier, and the magnetic carrier is a ferrite containing a divalent metal such as iron, magnetite, Mn, Zn, Cu, A volume average particle size of 20 to 100 μm is preferred. When the average particle size is less than 20 μm, carrier adhesion is likely to occur on the photoreceptor 1 during development. Cheap. In addition, Cu ferrite containing Zn is preferable because of high saturation magnetization, but can be appropriately selected according to the process of the image forming apparatus. The resin for coating the magnetic carrier is not particularly limited, and examples thereof include silicone resin, styrene-acrylic resin, fluorine-containing resin, and olefin resin. In the manufacturing method, the coating resin may be dissolved in a solvent, sprayed into a fluidized bed and coated on the core, or the resin particles are electrostatically attached to the core particles and then thermally melted for coating. It may be a thing. The resin to be coated has a thickness of 0.05 to 10 μm, preferably 0.3 to 4 μm. EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example, this invention is not limited only to these Examples. In addition, "part" showing the quantity in the following sentence means a weight part.

-Preparation of photoconductor By coating and drying an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution in the following composition on a φ30 mm aluminum cylinder in sequence. A 5 μm subbing layer, a 0.2 μm charge generation layer, and an 18 μm charge transport layer were formed to produce a photoreceptor.
[Coating liquid for undercoat layer]
・ Alkyd resin 6 parts (Beccosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
Melamine resin 4 parts (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals)
・ Titanium oxide 40 parts ・ Methyl ethyl ketone 50 parts [Coating liquid for charge generation layer]
-Bisazo pigment of the following structural formula (1) 2.5 parts-Polyvinyl butyral (XYHL, manufactured by UCC) 0.5 part-Cyclohexanone 200 parts-Methyl ethyl ketone 80 parts

[Coating liquid for charge transport layer]
・ 10 parts of bisphenol Z polycarbonate (Panlite TS-2050, manufactured by Teijin Chemicals)
-7 parts of low molecular charge transport material (D-1) of the following structural formula (2)-100 parts of tetrahydrofuran-1 part of tetrahydrofuran solution of 1% silicone oil (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

Evaluation Evaluation device used was a modified black station of MFP image Neo Neo C600 manufactured by Ricoh Co., Ltd. The process cartridge is configured as shown in FIG. 2, a hard resin roller having a diameter of 11 mm is used as the charging member, and the gap with the photosensitive member is adjusted to 50 μm. As the charging condition, an alternating electric field in which a sinusoidal wave with Vpp = 2 kV and frequency = 2.1 kHz was superimposed as an AC component on a DC component of −600 V was applied. In addition, zinc stearate molded in a rectangular parallelepiped shape as the lubricant 3b is brought into contact with the brush roller 3a with a pressure of 800 mN, and zinc stearate is supplied onto the photosensitive member via a brush. As for the fiber of the brush roller, the fiber with a long bristle has a bristle length of 5 mm, the fiber thickness is 2 denier, and the fiber density is 150,000 fibers / inch ² . The shorter fiber has a hair length of 3 mm, a fiber thickness of 15 denier, and a fiber density of 20,000 fibers / inch ² . The material is polyester. The area ratio of long fibers and short fibers is 1: 1.
The fibers with long hairs are in contact with both the lubricant and the photoconductor, whereas the fibers with short hairs are in contact only with the photoconductor. Using this modified evaluation machine, the photoconductor produced as described above was mounted and 100,000 sheets were run. If black streaks occur on the image during running, count the number of sheets until the black streaks occur, and measure the amount of photoconductor wear and lubricant consumption after evaluation for those with no black streaks up to 100,000. It was decided to. The results are shown in Table 1.

In the same manner as in Example 1, an undercoat layer, a charge generation layer, and a charge transport layer were applied.
On this charge transport layer, a surface layer coating solution having the following composition is spray-coated, and light irradiation is performed under the conditions of a metal halide lamp: 160 W, irradiation distance: 120 mm, irradiation intensity: 200 mW / cm ² , and irradiation time: 20 seconds. Then, drying was performed at 130 ° C. for 20 minutes to provide a protective layer of 4 μm, and a photoconductor was prepared, and mounted on a process cartridge having the same configuration as in Example 1, and the same evaluation was performed.

[Coating liquid for protective layer]
-Radical polymerizable monomer that does not have a charge transporting structure 10 parts Caprolactone-modified dipentaerythritol hexaacrylate
(KAYARAD DPCA-120, Nippon Kayaku)
Molecular weight: 1947, number of functional groups: 6 functions, molecular weight / number of functional groups = 325
10 parts of radically polymerizable compound having a charge transporting structure (Exemplary Compound No. 54)
-Photopolymerization initiator 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
・ 100 parts of tetrahydrofuran

  Using the photoreceptor of Example 2, the same evaluation was performed with the configuration shown in FIG. The cleaning brush roller 8e has the same configuration as in the first and second embodiments.

Using the photoreceptor of Example 2, the same evaluation was performed with the configuration shown in FIG. However, the fibers of the cleaning brush roller are both 3 denier, the fiber density is 100,000 fibers / inch ² and the long fibers are straight hairs with a hair length of 5 mm, and the short fibers are 3 mm with a hair length of 3 mm. A brush roller with a loop shape was used. The material is polyester. The area ratio of long fibers and short fibers is 1: 1.

  Using the photoreceptor of Example 2, the same evaluation was performed with the configuration of FIG. However, the fibers of the cleaning brush roller were the same as those in Example 1, and only a fiber having a bristles length of 5 mm was a brush roller that fell down in an oblique direction as shown in FIG. 5a.

The same evaluation as in Example 2 was performed except that the following compounds were used as the lubricant.
A composition comprising 60% normal paraffin (weight average molecular weight Mw 640) and 40% sorbitan tristearate (HLB = 1.5) as a hydrophobic organic compound (A) is melted at 120 ° C. and poured into a mold. A rectangular parallelepiped lubricant was prepared.
The HLB value was calculated by the so-called Kawakami equation of Equation (3).
HLB = 7 + 11.7 log (Mw / Mo) Formula (3)
Here, Mw is the molecular weight of the hydrophilic portion, Mo is the molecular weight of the lipophilic group, and log is the common logarithm.

<Comparative Example 1>
In Example 2, the same evaluation was performed with the same configuration except that the brush roller 3a was a polyester brush roller having a bristle length of 3 mm, a fiber thickness of 15 denier, and a fiber density of 20,000 fibers / inch ^2. It was.

<Comparative example 2>
In Example 2, the same evaluation was performed with the same configuration except that the brush roller 3a was a polyester brush roller having a bristle length of 3 mm, a fiber thickness of 2 denier, and a fiber density of 150,000 fibers / inch ^2. It was.

<Comparative Example 3>
In Example 2, the brush roller 3a has two kinds of lengths of hairs, the length of hairs is 3 mm, the thickness is 2 denier, the fiber density is 150,000 fibers / inch ² and the length of the hairs is 5 mm, and the thickness is 15 deniers. The same evaluation was performed with the same configuration except that a brush roller in which polyester fibers having a fiber density of 20,000 fibers / inch ² were bonded at an area ratio of 1: 1 was used.
Table 2 shows the results of Examples 2 to 6 and Comparative Examples 1 to 3.

As described above, in Examples 1 to 6, the charging member is soiled by uniformly applying a lubricant on the photoconductor by combining long and thin fibers with short hairs and short and thick fibers. Since the surface of the photoconductor was adequately polished with a brush, a good image free from black streaks due to charging stains and image blur due to filming could be maintained over a long period of time.
On the other hand, in the comparative example, black streaks due to contamination of the charging member and image blur due to filming occur at an early stage.
In Example 2, since a crosslinkable resin was included in the surface layer of the photoconductor, a more excellent effect on photoconductor wear was obtained.
In Example 4, as in Examples 1 to 3, no abnormal image was generated and the durability was satisfied.
In Example 5, the photoreceptor wear amount and the lubricant consumption amount are smaller than those in Examples 1 to 4.
In Example 6, as in Examples 1 to 5, no abnormal image was generated and the durability was satisfied.

1 is a diagram illustrating a schematic configuration of an image forming apparatus to which the present invention is applied. It is a figure which expands and shows one of four image formation units. It is a figure showing other embodiments of a lubricant application device. It is a figure for demonstrating the structure of a brush. It is a figure which shows other embodiment of a brush roller. FIG. 3 is a diagram schematically illustrating the shape of a toner for explaining a shape factor. It is a figure which shows typically the shape of the toner used for this invention.

Explanation of symbols

1 Photoconductor (image carrier)
2 Charging device 3 Lubricant coating device 4 Developing device 7 Fixing device 8 Cleaning device 9 Exposure device

Claims (8)

  At least an image carrier on which a toner image is carried and conveyed, a charging member provided near or in contact with the surface of the image carrier to charge the surface of the image carrier by proximity discharge, and on the image carrier In an image forming apparatus comprising a cleaning member that abuts and a lubricant application unit that applies a lubricant to the surface of the image carrier, the lubricant application unit includes a solid lubricant and a brush roller, and the brush roller is a bristle. Composed of two types of fibers having different foot lengths, the longer fiber of the brush roller contacts the lubricant and the image carrier, whereas the shorter fiber of the foot has the lubricant. An image forming apparatus that is set so as to be in contact with only an image carrier without being in contact with the fiber, and the diameter of the longer fiber of the bristle is thinner than that of the shorter fiber.   At least an image carrier on which a toner image is carried and conveyed, a charging member provided near or in contact with the surface of the image carrier to charge the surface of the image carrier by proximity discharge, and on the image carrier In an image forming apparatus comprising a cleaning member that abuts and a lubricant application unit that applies a lubricant to the surface of the image carrier, the lubricant application unit includes a solid lubricant and a brush roller, and the brush roller is a bristle. Composed of two types of fibers having different foot lengths, the longer fiber of the brush roller contacts the lubricant and the image carrier, whereas the shorter fiber of the foot has the lubricant. An image forming apparatus that is set so as to be in contact with only the image carrier without contacting with the image carrier, and the elastic coefficient of the longer fiber of the bristles is smaller than that of the shorter fiber.   3. The image forming apparatus according to claim 1, wherein the fibers having shorter hairs are formed in a loop shape. 4.   4. The image forming apparatus according to claim 1, wherein the fibers having longer hairs are planted obliquely with respect to the longitudinal direction of the roller shaft. 5. .   5. The image forming apparatus according to claim 1, wherein the brush roller has a configuration in which a plurality of strip-like sheets having different fiber lengths are arranged and wound around a metal core in a spiral shape. Image forming apparatus.   6. The image forming apparatus according to claim 1, wherein the lubricant is a metal soap.   7. The image forming apparatus according to claim 1, wherein the lubricant contains a hydrophobic organic compound (A) and an amphiphilic organic compound (B). .   8. The image forming apparatus according to claim 1, wherein the image carrier has a protective layer made of a cross-linking curable resin as a surface layer.

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